Anyone familiar with the new Rotamax rotary engine company?SELLER REI at http://rotaryaircraftengines.com/enginemodels2.htm
FACTORY Rotamax at http://www.rotamax.net/history.html
USER Airgryo Aviation at http://www.airgyro.com/latestnews.htm
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New rotary engine out.
- Thread starter Garth
- Start date
Anyone familiar with the new Rotamax rotary engine company?SELLER REI at http://rotaryaircraftengines.com/enginemodels2.htm
FACTORY Rotamax at http://www.rotamax.net/history.html
USER Airgryo Aviation at http://www.airgyro.com/latestnews.htm
Well it looks like they've got aluminum rotor housings. That is great for weight and hopefully they wear ok. No Mazda parts except seals. That is probably good.
I don't buy some of their comparisons to the EJ25 Subaru. More low end torque? Near equal power? Nope. Where do they get their info from? Latest EJ25 is 173hp at 6000 and 166 lb./ft. at 4400 rpm. Seems they are short about 40hp and 40 lb./ft. Since when does an EJ25 weigh 390 pounds? Please just publish facts guys.
They do appear very light and compact.
I do wish these guys well. These are the kinds of things the Wankel has needed in aviation. Looks good on the computer. Now they just need about 10,000 flight hours to prove what they say.
I'll wait and see what kind of muffler they have to supply that lasts and keeps this puppy from ripping out eardrums.
Very interesting and hope to see more info on these.
I don't buy some of their comparisons to the EJ25 Subaru. More low end torque? Near equal power? Nope. Where do they get their info from? Latest EJ25 is 173hp at 6000 and 166 lb./ft. at 4400 rpm. Seems they are short about 40hp and 40 lb./ft. Since when does an EJ25 weigh 390 pounds? Please just publish facts guys.
They do appear very light and compact.
I do wish these guys well. These are the kinds of things the Wankel has needed in aviation. Looks good on the computer. Now they just need about 10,000 flight hours to prove what they say.
I'll wait and see what kind of muffler they have to supply that lasts and keeps this puppy from ripping out eardrums.
Very interesting and hope to see more info on these.
gmcjetpilot
Well Known Member
Ross said that?
You sound like me. I noticed they did not address fuel consumption or noise.
WHAT? I can't believe you said they "need about 10,000 flight hours to prove what they say".
You sound like me. I noticed they did not address fuel consumption or noise.been in use for years
See at http://rotaryaircraftengines.com/enginemodels.htm the Rotamax 1300 CC turbocharged is 180 HP at 6000 RPM and in another article is says it is 170Toque HP at 5000 RPM cruise, and it is only 150 lbs. Also listen to news cast from last air show at Oshkosh, http://www.mefeedia.com/entry/3204436/
In which Paul Plack talks with Eric Barger, president of RotaMax Rotary Engines, and how his company is introducing a line of aviation rotaries based on a long-established, non-automotive design from OMC. They also describe how, along with the history article in their website, the engine already has over 10,000 hours in snow machines and other applications from years of mass production at OMC. It has always been aluminum and is well known as "run forever" motors. OMC went out of business years ago but not because of the rotary engine. They produced a ton of recreation equipment from Motor-homes to boats and snowmobiles, farm and lawn equipment etc.
The snowmobiles had good muffler systems, these are not as loud as Mazda's anyway and no where near the rpm either, which is the main reason for the noise difference. Rotamax peaks at 6,000 rpm instead of 8 to 10 grand on the Mazda engines.
See at http://rotaryaircraftengines.com/enginemodels.htm the Rotamax 1300 CC turbocharged is 180 HP at 6000 RPM and in another article is says it is 170Toque HP at 5000 RPM cruise, and it is only 150 lbs. Also listen to news cast from last air show at Oshkosh, http://www.mefeedia.com/entry/3204436/
In which Paul Plack talks with Eric Barger, president of RotaMax Rotary Engines, and how his company is introducing a line of aviation rotaries based on a long-established, non-automotive design from OMC. They also describe how, along with the history article in their website, the engine already has over 10,000 hours in snow machines and other applications from years of mass production at OMC. It has always been aluminum and is well known as "run forever" motors. OMC went out of business years ago but not because of the rotary engine. They produced a ton of recreation equipment from Motor-homes to boats and snowmobiles, farm and lawn equipment etc.
The snowmobiles had good muffler systems, these are not as loud as Mazda's anyway and no where near the rpm either, which is the main reason for the noise difference. Rotamax peaks at 6,000 rpm instead of 8 to 10 grand on the Mazda engines.
Fuel consumption is listed in the specs but I'll wait and see what the real world says.
Since these don't use Mazda core parts, the whole design is relatively unproven unlike say the Subaru EJs which have 250,000+ flight hours cumulatively not to mention billions of hours on the ground. I did not see mention of flight hours on their site but could have missed that.
Since these don't use Mazda core parts, the whole design is relatively unproven unlike say the Subaru EJs which have 250,000+ flight hours cumulatively not to mention billions of hours on the ground. I did not see mention of flight hours on their site but could have missed that.
Good to know there is some ground history behind these.
I just don't believe, ready to run weights like this. Longblock maybe but not as installed with ancillaries. The big thing again is the cost. Most gyro guys will not drop this kind of dough on an engine when a Sube is $500. If you need good power to weight ratios, the EJ255 (STI) does 300hp with a 215 lb. longblock. The Rotamax 1300 only puts out 130hp so their comparison to the EJ25 is not valid.
I do think it is cool that these guys are offering engines for aviation use. Another choice for those so inclined.
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cjensen
Well Known Member
The double asterick at the bottom says-
** Weight does not include PSRU, starting, charging, exhaust, cooling, or other accessory systems.
Probably double the weight to about 300 or so? Still in the ballpark to 180hp Lyc...
Also, on a side note related...Mazda unveiled the 16x recently with aluminum end housings. Should shave 20 or so pounds from the current Renesis...
Yep so why does a Sube weigh 160 pounds more in the rest of their data? A Lycoming also weighs "hundreds" of pounds more?
All engine kit suppliers can do themselves a favor and get their facts straight when comparing their engines to others. They just look foolish and it hurts their credibility right off the bat.
Might as well list the total weight with drive, coolant, starter, alternator, exhaust, rads, turbo etc. Engine weight alone is not very meaningful. I think you are right, ready to run at around 300 lbs. which is quite good and comparable to a 360.
Shades of the 50% less fuel flows, lower weight, hp claimed by some of the Sube vendors in the past or Deltahawk's Lycoming comparison fuel flow numbers. Headwinds, prop, weather affect fuel flow in their notes at the bottom? News to me.
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See at http://rotaryaircraftengines.com/PDF/RotarySpecSheet.pdf The weight for the 180 HP (170 continuous torque HP to prop at 5500 cruise RPM) is only 165 lbs with all acc not on the factory unit.
The Australian aircraft company using it in all their planes verified this and its stated performance, which is why they adopted it as their engine in all their airplane models they make.
This is not an adapted auto engine and has no similarity to a Mazda engine except the seal, and is closer to the Wankel design than Mazda's. The porting and coatings and aluminum body are all unique to the Rotamax Rotary and is what makes it a low RPM, cool running with water jacket cooling on only the hot side of the engine, no oil crankcase or oil/filter to change ever, engine that puts out more power at FAR lower temps and RPM than any auto conversion unit and IS much lighter.
However I am not trying to argue with a car engine in a aircraft enthusiast, while I would not consider it myself, to each his own, I just wish to hear from someone with direct input on knowledge and experience with Rotamax engines specifically as it is so dissimilar to the auto engines, even the accessories they use, they to are so much lighter than the auto stuff as car manufacturers don't need to save weight much. All I have so far in my search supports all their claims and then some.
The engine I need for my Seastar is 450 HP which is to be out in a year or two, and diesel version in two or three years, which is my time frame. The 450 HP will be in the 375 pound wet with all acc range and with 430 plus "continuous" HP to the prop at cruise, outperforms (blows away really) any non racing engine out there, lyconie's included. This engine is not full blown or maxed. It could do over twice it's rating as a race engine, in OMC's hands it was a race winner years in a row. Undefeated even for some years.
But I see a huge potential as a aircraft engine from an aircraft engine manufacturer, as opposed to used car engines modified by various mechanics using a verity of third party parts and aftermarket elements and hope it all does well.
Someone said 10,000 hours on it, well their is not a single aircraft rotary out their that can make that claim unless you just apply it to the all the combined cases and what guts that are not modified, of various year and model of used car engines, and very radically depending on what shop one used to do it all, or if he did it all himself in his garage.
Many buy a Lyconey for just this reason, but I have had my share of problems with them in over 500 hours flying, mostly in a Lake and Cessna's, and they are dinosaurs anyway and one must baby an air cooled engine so much to, gets to hot, to cool etc. But I am not quick to go to auto conversions either, no matter who does it.
My other choice would be Crossflow Subaru for the same reason, and aircraft version built new from scratch. Aerocat has had a 250 in the cat for 2 years now and has selected it as the engine they will use. Their past is horrible but new owners and revamped factory may make the difference.
Kirk Creelman (designed and started the Seawind and now is doing the new Aerocat) is well aware of their past, but has been to their plant and worked with them and says they are now the real thing. Go figure. So Aerocat has agreed to use them exclusively as they are only a 100 or so miles away. Crossflow will be putting out a large power unit shortly also.
The Australian aircraft company using it in all their planes verified this and its stated performance, which is why they adopted it as their engine in all their airplane models they make.
This is not an adapted auto engine and has no similarity to a Mazda engine except the seal, and is closer to the Wankel design than Mazda's. The porting and coatings and aluminum body are all unique to the Rotamax Rotary and is what makes it a low RPM, cool running with water jacket cooling on only the hot side of the engine, no oil crankcase or oil/filter to change ever, engine that puts out more power at FAR lower temps and RPM than any auto conversion unit and IS much lighter.
However I am not trying to argue with a car engine in a aircraft enthusiast, while I would not consider it myself, to each his own, I just wish to hear from someone with direct input on knowledge and experience with Rotamax engines specifically as it is so dissimilar to the auto engines, even the accessories they use, they to are so much lighter than the auto stuff as car manufacturers don't need to save weight much. All I have so far in my search supports all their claims and then some.
The engine I need for my Seastar is 450 HP which is to be out in a year or two, and diesel version in two or three years, which is my time frame. The 450 HP will be in the 375 pound wet with all acc range and with 430 plus "continuous" HP to the prop at cruise, outperforms (blows away really) any non racing engine out there, lyconie's included. This engine is not full blown or maxed. It could do over twice it's rating as a race engine, in OMC's hands it was a race winner years in a row. Undefeated even for some years.
But I see a huge potential as a aircraft engine from an aircraft engine manufacturer, as opposed to used car engines modified by various mechanics using a verity of third party parts and aftermarket elements and hope it all does well.
Someone said 10,000 hours on it, well their is not a single aircraft rotary out their that can make that claim unless you just apply it to the all the combined cases and what guts that are not modified, of various year and model of used car engines, and very radically depending on what shop one used to do it all, or if he did it all himself in his garage.
Many buy a Lyconey for just this reason, but I have had my share of problems with them in over 500 hours flying, mostly in a Lake and Cessna's, and they are dinosaurs anyway and one must baby an air cooled engine so much to, gets to hot, to cool etc. But I am not quick to go to auto conversions either, no matter who does it.
My other choice would be Crossflow Subaru for the same reason, and aircraft version built new from scratch. Aerocat has had a 250 in the cat for 2 years now and has selected it as the engine they will use. Their past is horrible but new owners and revamped factory may make the difference.
Kirk Creelman (designed and started the Seawind and now is doing the new Aerocat) is well aware of their past, but has been to their plant and worked with them and says they are now the real thing. Go figure. So Aerocat has agreed to use them exclusively as they are only a 100 or so miles away. Crossflow will be putting out a large power unit shortly also.
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Im curious about the cooling system and other claims (not a lot of detail in the dwgs)- the btu's generated by an engine to produce x hp is going to be similar to other engines at the same power/fuel flow. The lower weight is interesting, but it is unclear just what is included. FWIW, My renesis shipping weight was just under 200 lbs dry with the big/heavy OEM intake manifold, wiring harness, and a welded steel pallet that have been discarded. The thing that I really like is the new modular design- just add another rotor assembly to increase power. Im guessing the advertised flat torque curve is a function of turbocharger's boost at low rpm and that power tapers off after 6000 rpm (possibly due to intake flow restrictions, similar to the older 13B's ???).
The 2-rotor turbocharged output seems to be very close to the NA Mazda renesis engine (also 2-rotor) at the same rpm: 180hp @ 6000 and 160hp @ 5000, peak torque 160 ft/lb at 5000. The biggest difference (I believe) is that the Mazda is capable of higher rpm and additional HP (up to 210 @ 7200 rpm); probably because of a slightly better fuel delivery/intake porting.
BTW, the "new/ slightly used for emissions testing" renesis motor cost $2000 complete, shipped to California from Australia. Id guess the normal renesis cost is closer to $5000 for used motors, but they are still hard to find. If one takes the effort to change an older/ much cheaper used 13B to peripheral intake ports, the power output is as good as the renesis or better. Depending on the actual weight difference, I'm not convinced that these motors are better than the Mazdas, given the huge difference in cost. Cooling is not a problem with well designed rads/ducting. BTW, you can get aluminum end housings from the Mazda racing after market, but they are expensive and not really needed, assuming that "equivalent to O-320/360" is our weight target in RV's.
The 2-rotor turbocharged output seems to be very close to the NA Mazda renesis engine (also 2-rotor) at the same rpm: 180hp @ 6000 and 160hp @ 5000, peak torque 160 ft/lb at 5000. The biggest difference (I believe) is that the Mazda is capable of higher rpm and additional HP (up to 210 @ 7200 rpm); probably because of a slightly better fuel delivery/intake porting.
BTW, the "new/ slightly used for emissions testing" renesis motor cost $2000 complete, shipped to California from Australia. Id guess the normal renesis cost is closer to $5000 for used motors, but they are still hard to find. If one takes the effort to change an older/ much cheaper used 13B to peripheral intake ports, the power output is as good as the renesis or better. Depending on the actual weight difference, I'm not convinced that these motors are better than the Mazdas, given the huge difference in cost. Cooling is not a problem with well designed rads/ducting. BTW, you can get aluminum end housings from the Mazda racing after market, but they are expensive and not really needed, assuming that "equivalent to O-320/360" is our weight target in RV's.
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My understanding was that Crossflow was defunct? Yes, no?
You're right, their past is horrible. I helped a couple ex customers fix multiple oversights and poor "engineering" with the turbos and EFI. I hope if they rise from the ashes, lots of things have been changed, especially their attitude towards customers. Retaining the name will make future prospects an uphill battle.
The new rotary stuff sounds promising. We'll be waiting for that RV flight test at Van's side by side with the Lycosaurus. If engine vendors are serious and confident in their products, this should be their first stop IMO.
Ya Harvey, its Airgyro at http://www.airgyro.com/latestnews.htm
They have some neet stuff. And thats one cool Gyrocopter for sure.
They have some neet stuff. And thats one cool Gyrocopter for sure.
Agreed for sure.
gmcjetpilot
Well Known Member
Where is the real Ross?
You mean the Gold standard is the Lycoming!!
I'm just tickled you agree, the Lycoming is the standard by which all others are compared.
(Folks and this is from a dyed in the wool auto-engine, alternative-engine proponent!)
Ross I assume you'll encourage Eggenfellner to do Van administered, observed, side-by fly-offs with Lyc powered RV's, proving and quantifying the performance of his subie kit engine product? What is good for rotary gang is good for the Subaru.
As far as cross-flow? its easy to build them up and exaggerate the product, but as far as I know few if any flew? Why do you all think it would be so much better than any other Subaru based engine installation like Eggenfellner? Yea there engine kit pictures looked nice, but besides pretty pictures and being a bad business, there's no proof, in my opinion, it was great, just pretty in pictures.
What happened to my ROSS? Was he abducted by aliens?
You mean the Gold standard is the Lycoming!!
I'm just tickled you agree, the Lycoming is the standard by which all others are compared.
(Folks and this is from a dyed in the wool auto-engine, alternative-engine proponent!)
Ross I assume you'll encourage Eggenfellner to do Van administered, observed, side-by fly-offs with Lyc powered RV's, proving and quantifying the performance of his subie kit engine product? What is good for rotary gang is good for the Subaru.
As far as cross-flow? its easy to build them up and exaggerate the product, but as far as I know few if any flew? Why do you all think it would be so much better than any other Subaru based engine installation like Eggenfellner? Yea there engine kit pictures looked nice, but besides pretty pictures and being a bad business, there's no proof, in my opinion, it was great, just pretty in pictures.
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Not sure how George figured this out but I'm being held on Proxima Centauri. The aliens are attempting to erase my memory of Subaru specs and replace them with ghastly images of some horrifying 360 cubic inch monster with 4 heads and cooling fins.
I've heard many rumors about Crossflow and them trying to certify their engines, major cash infused from wealthy backers, a new team, new state of the art facility, that they are gone, gone, gone and now they are back- it goes on.
Does anyone really know what is happening with them?
The Lycoming is the standard by which all other engine installations are judged since it works ok, warts and all and is the choice of the vast majority of RV builders. I'm not sure I ever disputed that. Much.
I'm just helping Jan whenever I can to sort out technical issues. He and Gary are pretty sharp dudes when it comes to engines and systems. I find it very interesting to be involved in some small way with their packages. I let Jan run his company as he sees fit, I'm just a lucky technical consultant (unpaid).
I do think all the vendors should take up Van's open invitation to fly head to head against their demo RVs. If they do manage to equal or outperform the Lycos, sales would be helped considerably I'd think. The new Wankel guys could prove their claims by flying a rotary RV up to Aurora and make us all believers.
I've heard many rumors about Crossflow and them trying to certify their engines, major cash infused from wealthy backers, a new team, new state of the art facility, that they are gone, gone, gone and now they are back- it goes on.
Does anyone really know what is happening with them?
The Lycoming is the standard by which all other engine installations are judged since it works ok, warts and all and is the choice of the vast majority of RV builders. I'm not sure I ever disputed that. Much.
I'm just helping Jan whenever I can to sort out technical issues. He and Gary are pretty sharp dudes when it comes to engines and systems. I find it very interesting to be involved in some small way with their packages. I let Jan run his company as he sees fit, I'm just a lucky technical consultant (unpaid).
I do think all the vendors should take up Van's open invitation to fly head to head against their demo RVs. If they do manage to equal or outperform the Lycos, sales would be helped considerably I'd think. The new Wankel guys could prove their claims by flying a rotary RV up to Aurora and make us all believers.
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Well its in the design and coating both. The plasma coating is a thermal-barrier coating developed by NASA for rotary engines, ceramic coatings resulting in the ability to withstand surface temperatures beyond the capability of conventional
metals or hydrocarbon lubricants, and further protects the metal from the hot side also.
The PS200 plasma-applied coating, developed at the NASA Lewis Research Center as an unlubricated wear coating consisting of chromium carbide with silver, and a fluoride eutectic for high temperature lubricity. Its applied over a thermal barrier coating in a plasma applied coating process and can permit engine operation without external lubrication. Runs much cooler and aids in the combustion process also to get better fuel economy, power output and much cleaner and greener emissions.
They also have a specially designed porting system for a charged cooling system that removes heat and makes it much more efficient than other rotary designs, see http://www.nasatech.com/Spinoff/spinoff2001/t2.html for a NASA article on Freedoms version of the OMC rotary http://www.freedom-motors.com/ (he has the rights to all non aircraft engine versions and works with Rotamax in the engines development.) A 10 HP rotary that fits in the palm of your hand, 160 HP that fits in a 5 gal paint bucket and you can put the lid on. He is Mr. Moller who makes the Sky car (see at http://www.moller.com/skyc.htm ) and they both use the same basic engine and coatings developed by NASA and the old OMC Corp.
Also if you listen to the newscast at http://www.mefeedia.com/entry/3204436/ where ANN's Paul Plack talks with Eric Barger, president of RotaMax Rotary Engines, it is explained pretty well, and when they were challenged by a septic saying “What are you doing different than other rotary engines with the charge-cooled?” , their design engineer replied with Charge-Cooling 101: Increasing load causes us (via human intervention or governor throttle response), to increase incoming air fuel which is drawn through the side of the rotor in a way that decreases the heat in the rotor (and E-shaft), while preheating the incoming air fuel mix, which results in the water jacket of our engine registering a lower temperature under heavier load and higher rpm settings. I know it sounds counter-intuitive, but its true. The heat is extracted from the rotor into the incoming air/fuel mix, then used in the combustion chamber and is sent out the exhaust.
Controlling ports, controlling fuel delivery, and controlling emissions, all are controlled by MotoTron electronics. That is what is different about our charge cooling. RotaMax routes the flow of the incoming air/fuel mix through the side of the E-Shaft and rotor (yes our E-Shaft and rotor both has holes, Mazda’s are solid) to extract heat from the rotor before reintroducing this newly preheated and turbulent air fuel stream to the combustion chamber. Mazda uses an oil splash to remove heat and that is nowhere near as efficient as this process.
Charge Cooling is a simpler, more efficient approach, but what is different is we’re controlling our charge cooling by the ECU as described above. Here is just one indication that Charge Cooling is more efficient than oil cooling of the rotor: Our engine liquid jacket is only around part of our engine center housing (from the spark to the exhaust) while the Mazda requires a water jacket all the way around the engine. His challenge would be true, if like a two stroke, our incoming air fuel only went directly into the combustion chamber. but It doesn't.
He’s right in thinking that the heat has to go somewhere, It does: out the exhaust. But, since he doesn't understand our intake runner’s path, he doesn't understand how the heat can leave the rotor in this convoluted, but important way. He just has not stood at our dyno and seen us add heavy load and throttle to an operating engine, and watch the water jacket temperature go down. The benefit of the ported body and the NASA coating work together to perform miracles. The smaller cooling system, radiator and no crankcase, filter or oil (the injector system uses much less oil) also reduce weight further.
This outfit ( http://www.powersportaviation.com/Home/Testing/Testing.htm ) has a good product line also, with PSRU's, (see at http://www.powersportaviation.com/Home/Reduction drive/Reduction drive.htm ) exhaust systems etc, and are for ALL rotaries including Mazda's. Really cool is the 20 pound no Governor or controls NASA designed prop, called the QCS (see it at the NASA site at http://sbir.gsfc.nasa.gov/SBIR/successes/ss/3-085text.html ) that Power Sport Aviation is also doing. Super efficient, no pilot burden at all, no controls, full self adjusted with no moving parts. Its high output design (based on the new turbine prop technologies) carbon fiber construction is a quarter the weight of its Constant speed counterpart, whose prop controls and the oil to drive it makes it 60 lbs heaver and it is still not as fast or powerful in thrust or output) So much new stuff coming on-line, way cool.
metals or hydrocarbon lubricants, and further protects the metal from the hot side also.
The PS200 plasma-applied coating, developed at the NASA Lewis Research Center as an unlubricated wear coating consisting of chromium carbide with silver, and a fluoride eutectic for high temperature lubricity. Its applied over a thermal barrier coating in a plasma applied coating process and can permit engine operation without external lubrication. Runs much cooler and aids in the combustion process also to get better fuel economy, power output and much cleaner and greener emissions.
They also have a specially designed porting system for a charged cooling system that removes heat and makes it much more efficient than other rotary designs, see http://www.nasatech.com/Spinoff/spinoff2001/t2.html for a NASA article on Freedoms version of the OMC rotary http://www.freedom-motors.com/ (he has the rights to all non aircraft engine versions and works with Rotamax in the engines development.) A 10 HP rotary that fits in the palm of your hand, 160 HP that fits in a 5 gal paint bucket and you can put the lid on. He is Mr. Moller who makes the Sky car (see at http://www.moller.com/skyc.htm ) and they both use the same basic engine and coatings developed by NASA and the old OMC Corp.
Also if you listen to the newscast at http://www.mefeedia.com/entry/3204436/ where ANN's Paul Plack talks with Eric Barger, president of RotaMax Rotary Engines, it is explained pretty well, and when they were challenged by a septic saying “What are you doing different than other rotary engines with the charge-cooled?” , their design engineer replied with Charge-Cooling 101: Increasing load causes us (via human intervention or governor throttle response), to increase incoming air fuel which is drawn through the side of the rotor in a way that decreases the heat in the rotor (and E-shaft), while preheating the incoming air fuel mix, which results in the water jacket of our engine registering a lower temperature under heavier load and higher rpm settings. I know it sounds counter-intuitive, but its true. The heat is extracted from the rotor into the incoming air/fuel mix, then used in the combustion chamber and is sent out the exhaust.
Controlling ports, controlling fuel delivery, and controlling emissions, all are controlled by MotoTron electronics. That is what is different about our charge cooling. RotaMax routes the flow of the incoming air/fuel mix through the side of the E-Shaft and rotor (yes our E-Shaft and rotor both has holes, Mazda’s are solid) to extract heat from the rotor before reintroducing this newly preheated and turbulent air fuel stream to the combustion chamber. Mazda uses an oil splash to remove heat and that is nowhere near as efficient as this process.
Charge Cooling is a simpler, more efficient approach, but what is different is we’re controlling our charge cooling by the ECU as described above. Here is just one indication that Charge Cooling is more efficient than oil cooling of the rotor: Our engine liquid jacket is only around part of our engine center housing (from the spark to the exhaust) while the Mazda requires a water jacket all the way around the engine. His challenge would be true, if like a two stroke, our incoming air fuel only went directly into the combustion chamber. but It doesn't.
He’s right in thinking that the heat has to go somewhere, It does: out the exhaust. But, since he doesn't understand our intake runner’s path, he doesn't understand how the heat can leave the rotor in this convoluted, but important way. He just has not stood at our dyno and seen us add heavy load and throttle to an operating engine, and watch the water jacket temperature go down. The benefit of the ported body and the NASA coating work together to perform miracles. The smaller cooling system, radiator and no crankcase, filter or oil (the injector system uses much less oil) also reduce weight further.
This outfit ( http://www.powersportaviation.com/Home/Testing/Testing.htm ) has a good product line also, with PSRU's, (see at http://www.powersportaviation.com/Home/Reduction drive/Reduction drive.htm ) exhaust systems etc, and are for ALL rotaries including Mazda's. Really cool is the 20 pound no Governor or controls NASA designed prop, called the QCS (see it at the NASA site at http://sbir.gsfc.nasa.gov/SBIR/successes/ss/3-085text.html ) that Power Sport Aviation is also doing. Super efficient, no pilot burden at all, no controls, full self adjusted with no moving parts. Its high output design (based on the new turbine prop technologies) carbon fiber construction is a quarter the weight of its Constant speed counterpart, whose prop controls and the oil to drive it makes it 60 lbs heaver and it is still not as fast or powerful in thrust or output) So much new stuff coming on-line, way cool.
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gmcjetpilot
Well Known Member
Fuel Econ and Noise Two challenges as always for Wankels
One, the shape of the combustion area, rather large (low compression), long and skinny. This affects fuel efficiency. You're just going to have to blow some unburnt fuel out the pipes as part of doing business in a Wankel engine. There is a cost to not having valves.
Two, the exhaust velocities and temps are high thus making the exhaust noise and exhaust design a real challenge, especially in a plane where weight, room and drag are issues.
There is so much you can do about ONE & TWO in the "paradigm" or design of a Wankel to overcome them.
I'm not buying coating or there are significant breakthrough's to over come the inherent drawback, low fuel efficiency compared to a 4-stroke piston engine. As well, I see no change in the basic Wankel concept, just small changes. Many people have designed Wankel engines for cars, motorcycles, marine and even aircraft use (Curtiss-Wright RC2-60 Wankel rotary engine). They all had an attraction to draw designers to incorporate them, but in the end, they suffered mostly from low efficiency relative to pistons. What happend to all the promise of Mistral?
There was Power Sports Rotary kit which proved to be good performing, expensive but good. It basically matched the performance of the 180HP Lyc, using an expensive electrical constant speed MT prop. However it did this at the expense of fuel burn, which was eye watering. Also the subjective topic of noise by ground observers where definitive, the rotary was obtrusive. The Power Sports did have resonable weight but still more than a typical 180HP Lyc installation.
I not negative just for fun. I'm just saying what we know today and what this company "promises" does not match what we as a experimental aircraft community have observed. We're like the state of Missouri, "show me".
Hopeful but I'm still skeptical until like Ross said, they PROVE their numbers in controlled, independent test, side-by-side with Lycoming powered planes. I really think the Rotary is great (owned two rotary Mazda's), but it still has TWO main drawbacks, fuel economy and exhaust noise/temp and probably always will. Turbo-charging is a good idea with rotary engines, because of the extra exhaust energy to capture. It also slightly helps the low compression issue and lowers noise, but as always, turbos add more weight and complexity.
PS Any reference to "Mr. Moller who makes the Sky car" is a RED FLAG of pure bogosity to me. There is nothing I would believe that this guy says about aviation or technology. He is a salesman and apparently a good one. He has been keeping this "Sky Car" thing going for a long time and still gets people to invest money.
Garth no offense, it all sounds impressive, but inherent in the rotary design, besides positives, are two drawbacks which are part of the design and inescapable.
One, the shape of the combustion area, rather large (low compression), long and skinny. This affects fuel efficiency. You're just going to have to blow some unburnt fuel out the pipes as part of doing business in a Wankel engine. There is a cost to not having valves.
Two, the exhaust velocities and temps are high thus making the exhaust noise and exhaust design a real challenge, especially in a plane where weight, room and drag are issues.
There is so much you can do about ONE & TWO in the "paradigm" or design of a Wankel to overcome them.
I'm not buying coating or there are significant breakthrough's to over come the inherent drawback, low fuel efficiency compared to a 4-stroke piston engine. As well, I see no change in the basic Wankel concept, just small changes. Many people have designed Wankel engines for cars, motorcycles, marine and even aircraft use (Curtiss-Wright RC2-60 Wankel rotary engine). They all had an attraction to draw designers to incorporate them, but in the end, they suffered mostly from low efficiency relative to pistons. What happend to all the promise of Mistral?
There was Power Sports Rotary kit which proved to be good performing, expensive but good. It basically matched the performance of the 180HP Lyc, using an expensive electrical constant speed MT prop. However it did this at the expense of fuel burn, which was eye watering. Also the subjective topic of noise by ground observers where definitive, the rotary was obtrusive. The Power Sports did have resonable weight but still more than a typical 180HP Lyc installation.
I not negative just for fun. I'm just saying what we know today and what this company "promises" does not match what we as a experimental aircraft community have observed. We're like the state of Missouri, "show me".
Hopeful but I'm still skeptical until like Ross said, they PROVE their numbers in controlled, independent test, side-by-side with Lycoming powered planes. I really think the Rotary is great (owned two rotary Mazda's), but it still has TWO main drawbacks, fuel economy and exhaust noise/temp and probably always will. Turbo-charging is a good idea with rotary engines, because of the extra exhaust energy to capture. It also slightly helps the low compression issue and lowers noise, but as always, turbos add more weight and complexity.
PS Any reference to "Mr. Moller who makes the Sky car" is a RED FLAG of pure bogosity to me. There is nothing I would believe that this guy says about aviation or technology. He is a salesman and apparently a good one. He has been keeping this "Sky Car" thing going for a long time and still gets people to invest money.
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Well you may be correct, but I hope not. I have only got substantiation so far and can find nothing to disprove their climes. Only negatives at all is auto engine enthusiast saying they don't see how it can be so different than they are, when the Rotamax (OMC engine actually) is quit different in many big ways, resulting in a lot of benefits. Yes, all rotaries are inherently low economy engines as your right, a product of no valves, but it does have big offsets also. Its circular motion and low moving parts do a lot, porting and coatings help.
But I do not intend to nor have I, compare it to another rotary. I said earlier I will never use a homebuilt engine. I compare only to factory manufactured brand new in a crate, full aircraft engine, not something made for a used car motor modified by 3rd party's from aftermarket and retrofitted, or from other car parts etc. Not saying thats bad, but am saying I will never do that.
The muffler exhaust system on the Powersport site is 81 DB on this engine, quieter than a similar Lyc, and the pitch is like a quiet turbine they say, and is the same on the Mazda engine too.
So like so many others out there, its a new Lycoming or this or the Crossflow for me, and a new twin turbocharged TIO-720 8 cyl Lycoming is 450 HP, weighs 725 lbs in full dress, has a cowl of 28"X36"X52" (minimum, needs a lot of air on 8 cyl's) and costs over a hundred grand... but its certified! It **** well better be. At 75% it burns 25 GPH at about 340 torque HP to the prop.
The 450 HP Rotamax is going to weigh 375 lbs with PSRU and all acc in full dress also, will burn 16.5 GPH at 5500 RPM cruise (its rated standard cruise setting) and is putting 435 torque HP to the prop, and is only 18" round (the cowling, 16" motor, not much bigger than the spinner) and 49" long (of course with PSRU) and cost about $40,000.00
The net result is almost 100 more HP to the prop, near 10 GPH less burn, 350 pounds lighter and the cross section performance gains make this a true winner at a $50,000.00 savings. So if it is even close to what they say, compared to other "true aircraft engines" it is a god send.
Your right on the Mollier Skycar, what a lose, any failure and the glide ratio is that of an anvil. Need the chute system on that one for sure, IF it ever gets off the tether line. But I understand its his money mostly, some grants, but a news article said he has over 200 million of his own money in it. However his rotary motor and equipment manufacturing business is going good I understand. See it at http://www.freedom-motors.com/ for jet boats and motorboats and equipment etc, at that 10 HP rotary that fits in the palm of your hand is sure impressive. See it on the NASA site at http://www.nasatech.com/Spinoff/spinoff2001/t2.html
Also the Mistral is something I am following, but it has no new design like Rotamax, coating, porting etc and is very heavy , foreign and expensive, but may be cool we'll see.
But I do not intend to nor have I, compare it to another rotary. I said earlier I will never use a homebuilt engine. I compare only to factory manufactured brand new in a crate, full aircraft engine, not something made for a used car motor modified by 3rd party's from aftermarket and retrofitted, or from other car parts etc. Not saying thats bad, but am saying I will never do that.
The muffler exhaust system on the Powersport site is 81 DB on this engine, quieter than a similar Lyc, and the pitch is like a quiet turbine they say, and is the same on the Mazda engine too.
So like so many others out there, its a new Lycoming or this or the Crossflow for me, and a new twin turbocharged TIO-720 8 cyl Lycoming is 450 HP, weighs 725 lbs in full dress, has a cowl of 28"X36"X52" (minimum, needs a lot of air on 8 cyl's) and costs over a hundred grand... but its certified! It **** well better be. At 75% it burns 25 GPH at about 340 torque HP to the prop.
The 450 HP Rotamax is going to weigh 375 lbs with PSRU and all acc in full dress also, will burn 16.5 GPH at 5500 RPM cruise (its rated standard cruise setting) and is putting 435 torque HP to the prop, and is only 18" round (the cowling, 16" motor, not much bigger than the spinner) and 49" long (of course with PSRU) and cost about $40,000.00
The net result is almost 100 more HP to the prop, near 10 GPH less burn, 350 pounds lighter and the cross section performance gains make this a true winner at a $50,000.00 savings. So if it is even close to what they say, compared to other "true aircraft engines" it is a god send.
Your right on the Mollier Skycar, what a lose, any failure and the glide ratio is that of an anvil. Need the chute system on that one for sure, IF it ever gets off the tether line. But I understand its his money mostly, some grants, but a news article said he has over 200 million of his own money in it. However his rotary motor and equipment manufacturing business is going good I understand. See it at http://www.freedom-motors.com/ for jet boats and motorboats and equipment etc, at that 10 HP rotary that fits in the palm of your hand is sure impressive. See it on the NASA site at http://www.nasatech.com/Spinoff/spinoff2001/t2.html
Also the Mistral is something I am following, but it has no new design like Rotamax, coating, porting etc and is very heavy , foreign and expensive, but may be cool we'll see.
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I might buy the power and weight of these new Wankels and see there are many major differences between these and the Madza engines. I don't buy the SFCs of these engines however. Highly unlikely from an engine design and thermodynamics perspective. This would be in diesel territory.
If they can do all this, I'll buy one and give up on piston engines forever and I suspect so will thousands of other builders.
I'll keep an open mind and watch for some independent tests.
If they can do all this, I'll buy one and give up on piston engines forever and I suspect so will thousands of other builders.
I'll keep an open mind and watch for some independent tests.
gmcjetpilot
Well Known Member
Don't believe the hype
The actually did some noise dB meter test. The Rotaries where louder (83, 84 and 94 peek on takeoff) verses a 360 Lyc that was a full 11 dB less, in the 69-73 dB range. The proof is in the ear bleeding. Note, fuel burn, 30% to 45% or more for the powersport v Lycoming. Do you think these guys made that much improvement? There is no getting around low compression and long, skinny, shallow combustion areas where the flame front is severely limited. It's just inherent to the Wankel design. I wish it where true and I was 1/10th as smart as Dr. Wankel who invented the engine.
First - They have a picture of a "test stand" engine (and a gyro copter & motorcycle). They also have pretty computer drawings. I've followed many "test stand" engines. The birth rate is nil to zero. Also, don't forget to include the extra 1000-1500 hours you'll spend, not to mention money, to fabricate little parts like the engine mount? At least the Real World Solution (RWS) guys have parts, experience and are flying planes.
Second, @ 75% power a IO-540 will burn much less than 25 gph if you lean it, as you should of course. You can easily get it to 14-16 gph (or less).
Third HP - Direct drive Lycs always outperform alternative engine with the same claimed HP. Look at the Powersports. They claim 215HP, but where doing about what the 180HP Lyc was doing. RWS 13B based rotary claims a 180HP, but he raced in the 160HP class at sun-N-fun? He does OK in the 160HP class, but what's up with 180HP? Well when you don't dyno it's easy to say what ever you want. Also the PSRU tends to waste HP. Most all of these set-ups must use less than optimal fixed pitch props or expensive electric MT props, which we know are "smooth" but many MPH slower than a Hartzell. Work that $10,000 MT prop into your equation and the loss of 5-10 mph just from a prop choice standpoint.
Fourth Price - Even their $20,000 lower price comparison to a Lyc is an exaggeration. A brand new direct drive 260HP Lyc is $40,000. They charge $30,000 for 255 claimed HP (may be 200 HP at the prop). Apparently math is hard for them? (excuse the sarcasm but there is a pattern of exaggeration in their promotions.)
Last Weight - Their weight is suspect. Again until they have an installation (flying) its an "estimate" subject to reality. Every empty weight of every RV powered by an alternative engine weighs MORE. The Powersport's where 20 to 40 lbs more than the 200HP angle valve powered RV', and the Powesport's weigh 50-60 lbs more than the RV with the 180HP parallel valve Lycs. The Powersport powered RV's had performance of a 180HP Lyc but extra weight. Does this company you lust after really include the radiators, fluids, fuel pumps and extra battery to keep the electrically dependant EFI going at all time in their wild guess of total weight? I doubt it because they have none flying, do they? That is sad. Van never published performance numbers for any of his models until he had a flying prototype fully tested.
Did you know one of the powersport planes in the above Van's article was lost in a accident, sadly. It was due to a simple electrical problem. Mechanical carbs & FI with magnetos may be farm tractor technology, but they work without electrons.
Bottom line specific fuel burn is suspect and I would add weight to the list of claims I doubt. Also have you figured out what to do with the radiators. In fact do they have an installation, engine mount and all the systems to install it in a RV? Probably not. So how do they KNOW anything? They don't and they have not tested it. Beware!
Not true. Van tested this and the Powersport's "made enough noise to prompt a visit from the airport manager". Click below last par right side.
The actually did some noise dB meter test. The Rotaries where louder (83, 84 and 94 peek on takeoff) verses a 360 Lyc that was a full 11 dB less, in the 69-73 dB range. The proof is in the ear bleeding.
Note, fuel burn, 30% to 45% or more for the powersport v Lycoming. Do you think these guys made that much improvement? There is no getting around low compression and long, skinny, shallow combustion areas where the flame front is severely limited. It's just inherent to the Wankel design. I wish it where true and I was 1/10th as smart as Dr. Wankel who invented the engine.
Look no offense but I don't believe everything I hear. I mean prove it, or have they tested this in a RV-?. How do they know unless they have a full tested installation? It's propaganda to me at this point.
First - They have a picture of a "test stand" engine (and a gyro copter & motorcycle). They also have pretty computer drawings. I've followed many "test stand" engines. The birth rate is nil to zero. Also, don't forget to include the extra 1000-1500 hours you'll spend, not to mention money, to fabricate little parts like the engine mount? At least the Real World Solution (RWS) guys have parts, experience and are flying planes.
Second, @ 75% power a IO-540 will burn much less than 25 gph if you lean it, as you should of course. You can easily get it to 14-16 gph (or less).
Third HP - Direct drive Lycs always outperform alternative engine with the same claimed HP. Look at the Powersports. They claim 215HP, but where doing about what the 180HP Lyc was doing. RWS 13B based rotary claims a 180HP, but he raced in the 160HP class at sun-N-fun? He does OK in the 160HP class, but what's up with 180HP? Well when you don't dyno it's easy to say what ever you want. Also the PSRU tends to waste HP. Most all of these set-ups must use less than optimal fixed pitch props or expensive electric MT props, which we know are "smooth" but many MPH slower than a Hartzell. Work that $10,000 MT prop into your equation and the loss of 5-10 mph just from a prop choice standpoint.
Fourth Price - Even their $20,000 lower price comparison to a Lyc is an exaggeration. A brand new direct drive 260HP Lyc is $40,000. They charge $30,000 for 255 claimed HP (may be 200 HP at the prop). Apparently math is hard for them?
(excuse the sarcasm but there is a pattern of exaggeration in their promotions.)Last Weight - Their weight is suspect. Again until they have an installation (flying) its an "estimate" subject to reality. Every empty weight of every RV powered by an alternative engine weighs MORE. The Powersport's where 20 to 40 lbs more than the 200HP angle valve powered RV', and the Powesport's weigh 50-60 lbs more than the RV with the 180HP parallel valve Lycs. The Powersport powered RV's had performance of a 180HP Lyc but extra weight. Does this company you lust after really include the radiators, fluids, fuel pumps and extra battery to keep the electrically dependant EFI going at all time in their wild guess of total weight? I doubt it because they have none flying, do they? That is sad. Van never published performance numbers for any of his models until he had a flying prototype fully tested.
Did you know one of the powersport planes in the above Van's article was lost in a accident, sadly. It was due to a simple electrical problem. Mechanical carbs & FI with magnetos may be farm tractor technology, but they work without electrons.
If its too good to be true........... its probably not true. I would hold on to your money and make them prove it. Better get a lawyer to write up a contract to make them guarantee performance. If they don't sign it, run, don't walk. I guarantee you they will not guarantee squat. They will say it depends on your installation.
Well good, I'm happy for him. I don't wish the company ill, but the skycar is ridiculous. With 4 separate engines in each corner, when one goes TU it will be ugly. The Osprey V-22 tilt rotor and Chinook helicopter have interconnected drive shafts to keep both rotors going on one engine. It may need to descend on a single engine, but it will not do it a** over tea kettle out of control. Actually Mollier says it will fly with one engine out. I doubt it and again he has never tested it.
We have been waiting for years and its been quite for some time. I understand from they are trying to get certification with the FAA. Their market is towards retrofitting GA planes.
Bottom line specific fuel burn is suspect and I would add weight to the list of claims I doubt. Also have you figured out what to do with the radiators. In fact do they have an installation, engine mount and all the systems to install it in a RV? Probably not. So how do they KNOW anything? They don't and they have not tested it. Beware!
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cjensen
Well Known Member
The actually did some noise dB meter test. The Rotaries where louder (83, 84 and 94 peek on takeoff) verses a 360 Lyc that was a full 11 dB less, in the 69-73 dB range. The proof is in the ear bleeding.
Ear bleeding? C'mon! I know this comparison was fair, but I don't get what the big deal is. I mean, how much noise does a P-51 make on takeoff? LOUD!! They're about as common as a rotary RV. There are more and more rotary RV's taking flight all the time, and will soon be a little more commonplace, but how is it different? The noise is "better" out of a -51? I agree, but that is left to the individual. I happen to like the sound of a rotary and a P-51...my dad likes the Corsair's sound better...
It's noise either way, and so what if one RV is louder than another?
Just my opinion...
I think the aluminum rotor housings and no lubrication system would swing the weight issue to be on par with a Lycoming installation.
I'd be interested in how they get rid of all the heat on this design however even with the help of barrier and anti-friction coatings. Also of interest is how the rotor gearsets are lubricated?
Finally what is the basis for the very high TBOs mentioned? Have any engines run to say 3-4000 hours in an aviation applications? The overhaul costs would seem to be a real advantage compared to piston engines since the parts required would no doubt be a lot cheaper.
I'd be interested in how they get rid of all the heat on this design however even with the help of barrier and anti-friction coatings. Also of interest is how the rotor gearsets are lubricated?
Finally what is the basis for the very high TBOs mentioned? Have any engines run to say 3-4000 hours in an aviation applications? The overhaul costs would seem to be a real advantage compared to piston engines since the parts required would no doubt be a lot cheaper.
Podcast
A new podcast on the Rotamax engine...
http://www.aero-news.net/podcasts/casts/1/ann-special-feature-2007-10-12.mp3
--
Michael
A new podcast on the Rotamax engine...
http://www.aero-news.net/podcasts/casts/1/ann-special-feature-2007-10-12.mp3
--
Michael
cjensen
Well Known Member
RESOUNDING YES! I agreed with myself in my post, in case ya missed it...
But...it's still subjective.I listened to this. My goodness, I hope this guy is not an engineer.
The RX8 gets good fuel economy? Huh?
Machining technology doomed the Mazda rotary? Huh? Mazda had no problem building engines for their cars. Low sales as a result of poor fuel economy and pricing these cars out of existence doomed these engines and cars from Mazda.
He has no concept of torque and hp obviously. HP is work, torque is force.
Belt drives have a certain amount of damping? This is a commonly held misconception.
Now they are operating at similar air fuel ratios as piston engines. I'm wondering how SFCs will be better then with the high surface to volume ratio of the Wankel chamber?
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You obviously do not like rotaries or new engine designs. Most of your comments relate to the auto engines, not even similar to Rotamax other than they both spin in a circle. Powersport has a Rotamax I understand, just recently, but test stand only, not in any airplane yet, and the article was on auto engines (how old?) without their new muffler system their site says is 81 db on the rotaries.
I was comparing the Rotamax upcoming 450 HP 5 rotor engine when talking about the lycoming 450 HP IO-750 when I said 25 GPH, and 15 GPH on it wont even keep the plane I want airborne. I never even mentioned the little Lyc's you were talking about.
The price of aftermarket Lyc's on the IO-540 you mentioned was from $50 to $70 grand plus plus and were not even turbo's, those were all over a hundred grand plus plus. (plus plus is for adds of freight/ins/tax/etc) You must have found a fire sale or used engines somewhere, not a fair comparison to any new engine and their engines I spoke of were all turbocharged, fuel injected and had (Lyco's FADEC) type electronic engine controls. See at http://www.lycoming.textron.com/utility/global-resources/2007-Lycoming-Service-Engine-Price-List.pdf
But no one will ever win against someone defending their choice in something, you have one, you will defend it to the bitter end, human nature. My experience with Lyconies is not good, I had two blow up on me in Alaska, literally, blew a jug in flight, had to be rescued and all. But I just want to hear from someone with this engine or who knows someone who has one that can comment on it. I guess no one has them on this web site.
I was comparing the Rotamax upcoming 450 HP 5 rotor engine when talking about the lycoming 450 HP IO-750 when I said 25 GPH, and 15 GPH on it wont even keep the plane I want airborne. I never even mentioned the little Lyc's you were talking about.
The price of aftermarket Lyc's on the IO-540 you mentioned was from $50 to $70 grand plus plus and were not even turbo's, those were all over a hundred grand plus plus. (plus plus is for adds of freight/ins/tax/etc) You must have found a fire sale or used engines somewhere, not a fair comparison to any new engine and their engines I spoke of were all turbocharged, fuel injected and had (Lyco's FADEC) type electronic engine controls. See at http://www.lycoming.textron.com/utility/global-resources/2007-Lycoming-Service-Engine-Price-List.pdf
But no one will ever win against someone defending their choice in something, you have one, you will defend it to the bitter end, human nature. My experience with Lyconies is not good, I had two blow up on me in Alaska, literally, blew a jug in flight, had to be rescued and all. But I just want to hear from someone with this engine or who knows someone who has one that can comment on it. I guess no one has them on this web site.
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Not quite sure who's post you're referring to but let's correct some things here:
I see a 4 rotor engine on the site, maybe I missed the 5 rotor.
An IO-540 burns around 15 GPH at 75% power LOP. New price is just over $41K with new clones to be a bit cheaper. The 720s are obscenely expensive and few people would ever use a new one in an experimental. They are using about 20-22 gal./hr. in cruise LOP 75%.
Yes, jugs do blow up and crack on Lycomings, cranks sometimes break, cams go bad, valves stick, cases crack and some people are soured on them because they have had these experiences. Many are looking for alternatives these days. The Wankel may be it for some but these new ones have virtually no flight time to speak of and a lot of what is purported on their site is nonsense to the trained eye.
When I'm proved wrong, I'll eat my words. In the meantime, anyone is welcome to lay down their cash and be the first one with one in their aircraft to prove me wrong.
If anyone has any flight time on these engines, please pipe in and give us your thoughts.
I see a 4 rotor engine on the site, maybe I missed the 5 rotor.
An IO-540 burns around 15 GPH at 75% power LOP. New price is just over $41K with new clones to be a bit cheaper. The 720s are obscenely expensive and few people would ever use a new one in an experimental. They are using about 20-22 gal./hr. in cruise LOP 75%.
Yes, jugs do blow up and crack on Lycomings, cranks sometimes break, cams go bad, valves stick, cases crack and some people are soured on them because they have had these experiences. Many are looking for alternatives these days. The Wankel may be it for some but these new ones have virtually no flight time to speak of and a lot of what is purported on their site is nonsense to the trained eye.
When I'm proved wrong, I'll eat my words. In the meantime, anyone is welcome to lay down their cash and be the first one with one in their aircraft to prove me wrong.
If anyone has any flight time on these engines, please pipe in and give us your thoughts.
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Jconard
Well Known Member
Garth,
You really are willing to take predictions as proven fact. Fact...the fuel power ratios you quote would put the specific fuel consumption somewhere in the range of a stationary turbocharged diesel...in other words, a level NEVER EVEN APPROXIMATED BY A WANKEL.
Second....the sound level is something never experienced in a rotary and the level you described for a Lyc is much higher than I have ever experienced.
Third...you blew a jug off a lycoming...twice...how? The only similar failures I am aware of are super high tuned engines..11.5 to 1 compression, etc.
Fourth...your dissertation on charge cooling indicates that as more power is being made...more fuel, and more cooling, and yet there is a claim of thermal efficiency requiring a better than stoichometric mixture, so it seems that there would be tesion between those two propositions. In other words, if it IS charge cooled, would not a lean mixture run hotter?
You describe the engine's capabilities as "we do this" and "we can achieve that"...are you associated with the engine? Or have you simply decided, before a single example has flown, that this is a viable or even existant option?
It is not that no one ON THIS WEBPAGE has flown one. It is that no one ANYWHERE has flown one. This is because, although the solidworks drawing are pretty, they are not engines, and solid works drawings do not fly.
You really are willing to take predictions as proven fact. Fact...the fuel power ratios you quote would put the specific fuel consumption somewhere in the range of a stationary turbocharged diesel...in other words, a level NEVER EVEN APPROXIMATED BY A WANKEL.
Second....the sound level is something never experienced in a rotary and the level you described for a Lyc is much higher than I have ever experienced.
Third...you blew a jug off a lycoming...twice...how? The only similar failures I am aware of are super high tuned engines..11.5 to 1 compression, etc.
Fourth...your dissertation on charge cooling indicates that as more power is being made...more fuel, and more cooling, and yet there is a claim of thermal efficiency requiring a better than stoichometric mixture, so it seems that there would be tesion between those two propositions. In other words, if it IS charge cooled, would not a lean mixture run hotter?
You describe the engine's capabilities as "we do this" and "we can achieve that"...are you associated with the engine? Or have you simply decided, before a single example has flown, that this is a viable or even existant option?
It is not that no one ON THIS WEBPAGE has flown one. It is that no one ANYWHERE has flown one. This is because, although the solidworks drawing are pretty, they are not engines, and solid works drawings do not fly.
First was on a Super Cub 150 in Denali Alaska with a big game outfitter in 1963. The Other one was near Anchorage in a Wilbur Flight School Cessna 150 on 6/15/1977.
They were standard engines. I do not know what caused the cubs but my 150 was a high time engine but the actual cause was never determined to my knowledge. I had just bought the plane (N2628J) from Wilbur's Flight School and they gave me my money back and took the plane back (totaled as it went up on its nose when the nose gear came down and fell over on the wing which bent it a little) My reference to the 5 rotor engine is not on their site, but I got it from them direct as something they are working on for Airgryo (see reference to it on Airgyro's site on the high speed twin pusher 6 place they plan)
I don't know where you get these prices, I guess the link I sent from Lycoming on their engines and prices is worthless, but it seams you keep quoting non turbo, standard carburetor engines from 3rd parties, but in any case this is my last attempt to defend my observations on the Rotamax. If they and others are just boldfaced lying and grossly overstating their product and misstating facts it will show soon enough, most stretch their claims a little, hard to come near stated cruise speed on any airplane or get the stated MPG of any cars window sticker, but everyone says they are off a mile not just stretching it and I don't see them being that irresponsible and outright shysters.
Course you all don't have one, or know of anyone who has, but are experts in the science and engineering of rotary engine designs to shoot their claims down no problem. I will take their word for now as all I have been able to verify so far has held up well. Two users (one a aircraft factory) claim the product did better than they expected, I just want more with that kind of findings, or as I said, I will move on to....Crosswind?
Buy the way, I was replying to post #22, but once again, I am not here to stand toe to toe with a Lyconie lover. I cannot defend what I don't have. I will not attempt to defend them again. Sorry for the apparent rubs. Over and out.
They were standard engines. I do not know what caused the cubs but my 150 was a high time engine but the actual cause was never determined to my knowledge. I had just bought the plane (N2628J) from Wilbur's Flight School and they gave me my money back and took the plane back (totaled as it went up on its nose when the nose gear came down and fell over on the wing which bent it a little) My reference to the 5 rotor engine is not on their site, but I got it from them direct as something they are working on for Airgryo (see reference to it on Airgyro's site on the high speed twin pusher 6 place they plan)
I don't know where you get these prices, I guess the link I sent from Lycoming on their engines and prices is worthless, but it seams you keep quoting non turbo, standard carburetor engines from 3rd parties, but in any case this is my last attempt to defend my observations on the Rotamax. If they and others are just boldfaced lying and grossly overstating their product and misstating facts it will show soon enough, most stretch their claims a little, hard to come near stated cruise speed on any airplane or get the stated MPG of any cars window sticker, but everyone says they are off a mile not just stretching it and I don't see them being that irresponsible and outright shysters.
Course you all don't have one, or know of anyone who has, but are experts in the science and engineering of rotary engine designs to shoot their claims down no problem. I will take their word for now as all I have been able to verify so far has held up well. Two users (one a aircraft factory) claim the product did better than they expected, I just want more with that kind of findings, or as I said, I will move on to....Crosswind?
Buy the way, I was replying to post #22, but once again, I am not here to stand toe to toe with a Lyconie lover. I cannot defend what I don't have. I will not attempt to defend them again. Sorry for the apparent rubs. Over and out.
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I know this about Wankels but I know of at least 2 instances where standard Lyco jugs departed the engine and one more here recently where a jug cracked wide open. The results were forced landings in each case.
Yes, this does really happen on occasion- fortunately not frequently.
I'd always buy new jugs at overhaul time if I was flying one of these.
gmcjetpilot
Well Known Member
There are no facts just philosophy
Garth:
Wayne here (ha ha just kidding wanted to say that). Good luck and I think folks are just watching out for you. No one hates Wankel's. I was driving the first rotaries in the USA in the 70's . (My parents bought it, I was a kid). The new RX8 Mazda is a cool car, but it needs expensive oil, uses oil between changes and has gas milage like high performance sports car do, poor to horible. I understand embarrassing the cool parts of the Wankel design, but you have to take the bad with the good. If you understand that you will be happy.
However in my opinion the info from that site is optimistic and is pegging my bogosity meter. They have shown success with little engines on Gyro copters. However a big engine on a plane is a different deal. There is no need to repeat myself, but how many built and flying?
BTW, A Lyc is a purpose built air-cooled piston aircraft gasoline engine. The Wankel is well a Wankel. Apples and oranges. Wankels have failed. Nothing mechaincal is imune, thus my first phylisophical qutoe: "S**t Happens".
No need to debate facts any more, because there are really few facts to speak of, in regards to this company or their products.
As usual all debates digress to becoming philosophical: If its too good to be true.........than its probably not true.
There ain't no such thing as a free lunch:
If you go for it because it turns you on great, but don't do it because it will be cheaper, it will not. Don't do it get more performance, it will likely not out perform a Lyc powered plane unless turboed and flown at altitude. Performance will be limited by prop, cooling drag and real HP at prop not sales brochure HP.
Installation issues: THEY HAVE INSTALLATION, just a note to ask about installation. The REAL genius will be in incorporating their engine into the airframe: engine mount, cooling, radiators, cowl, induction, oil cooler'(s) and so on. With out a complete integrated installation for the airframe, their engine is a drawing dream or test stand queen.
Garth:
Wayne here (ha ha just kidding wanted to say that). Good luck and I think folks are just watching out for you. No one hates Wankel's. I was driving the first rotaries in the USA in the 70's . (My parents bought it, I was a kid). The new RX8 Mazda is a cool car, but it needs expensive oil, uses oil between changes and has gas milage like high performance sports car do, poor to horible. I understand embarrassing the cool parts of the Wankel design, but you have to take the bad with the good. If you understand that you will be happy.
However in my opinion the info from that site is optimistic and is pegging my bogosity meter.
They have shown success with little engines on Gyro copters. However a big engine on a plane is a different deal. There is no need to repeat myself, but how many built and flying? BTW, A Lyc is a purpose built air-cooled piston aircraft gasoline engine. The Wankel is well a Wankel. Apples and oranges. Wankels have failed. Nothing mechaincal is imune, thus my first phylisophical qutoe: "S**t Happens".
No need to debate facts any more, because there are really few facts to speak of, in regards to this company or their products.
As usual all debates digress to becoming philosophical: If its too good to be true.........than its probably not true.
There ain't no such thing as a free lunch:
more weight?
higher fuel burn,
more cooling drag,
more ground noise,
less selection of Prop's
None are fatal, just the way it is. In exchange you get the rotary engine that goes round and hummmmm. higher fuel burn,
more cooling drag,
more ground noise,
less selection of Prop's
If you go for it because it turns you on great, but don't do it because it will be cheaper, it will not. Don't do it get more performance, it will likely not out perform a Lyc powered plane unless turboed and flown at altitude. Performance will be limited by prop, cooling drag and real HP at prop not sales brochure HP. Installation issues: THEY HAVE INSTALLATION, just a note to ask about installation. The REAL genius will be in incorporating their engine into the airframe: engine mount, cooling, radiators, cowl, induction, oil cooler'(s) and so on. With out a complete integrated installation for the airframe, their engine is a drawing dream or test stand queen.
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