Van's Air Force
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Geared Drives LS1 for RV-10
- Thread starter gipsowh
- Start date
David-aviator
Well Known Member
Kevin Horton
Well Known Member
What would the mpg of the Vette be at 185 kt (213 mph)?
11.7 gph at 185 kt, as reported earlier, is 18 mpg, which would be extremely impressive, if it pans out. This is very early, raw data, so the reported values may change as better data is obtained. We need to give the builder a chance to get more hours on the aircraft, and to get everything fully calibrated before we hold his feet too close to the fire expecting hard, credible data.
David-aviator
Well Known Member
I tend to agree.
Even if the engine is super efficient and running at a BSFC of .40, 11.7 gph converts to 168 HP. If the BSFC is .50 (more likely) it converts to 134 HP.
The -10 is a big airplane to be moved through the air that quick at that fuel flow.
It takes HP to get the job done and HP takes fuel, there's no other way to cut it.
Vans performance numbers for the -10 at 75% (195 HP) at 2200 pounds weight are 201 mph (174 KTAS) with an estimated burn of 16.2 gph.
185 knots at 11.2 gph is REALLY good if that's what the LS1 is doing.
Beyond that, congrats on getting the machine flying. That in itself is no small feat.
Kahuna
Moderatoring
Yes Kevin you are correct. I did not mean to come off as challenging to the owner. I did want to challenge the data. I have flown my fair share of alternative engines in various RV models. IMHO, these instruments need calibrating. I dont argue what it says, I challenge what it is.
I love the idea of these alternative engines. I have flown them when the builder/owners would not. I do not like the idea of poor data being propagated. This has caused many a builder to take a road that they later publically regret.
I would say that when a pilot puts data out for others to see, he/she should expected it to be challenged and vetted. Otherwise there is no point. A back of the napkin look at this data puts it in the highly questionable data category. I could be completely wrong, but I doubt it.
My 2 cents.
erich weaver
Well Known Member
photo of engine and references to Geared Drives in the EAA Experimentor -
scroll down to near end of http://www.eaa.org/experimenter/articles/2009-06_radiator.asp
erich
scroll down to near end of http://www.eaa.org/experimenter/articles/2009-06_radiator.asp
erich
Seems to me there's a guy in Canada doing just that with a Subaru 3.3 engine....
Ahhh, wonder who that is...???
Mine is too complicated for the average Joe IMO and I have no plans to offer parts or packages to others should it work well. I like the simplicity of an atmo V8 out of the crate for $5k if everything else in the package is engineered and tested well. Bud has the track record to do this I think after his success with the Wheeler.
We saw on Randy's Subaru, numbers which did not seem right initially (too good to be true). Later, with actual filling of the tanks before and after and switching for TO, climb and descent on one and cruise on the other, the numbers were indeed vetted. The conclusions we drew seemed to point to equal or less cooling drag than a Lycoming setup and/or considerably better propeller efficiency with the geared engine/ prop over a direct drive setup thrashing away at high rpm.
I'm not saying Bill's numbers are gold yet, just to keep an open mind that at least 3 other flying liquid cooled aircraft do indeed get better TAS/FF numbers than their air cooled brethren.
The LS engines have very high static compression ratios compared to your typical Lycoming and very flat torque curves indicating that VE is very high across a broad rpm range. It is not inconceivable to me that they have higher thermal efficiencies than typical air cooled engines. When turning them down around the low 3000s in cruise where friction is quite low... well hopefully some can see the possibilities here.
Jconard
Well Known Member
Ross,
I have seen the numbers, but not the FF and altitude for the turbo STI...could you please post them?
The intake and exit ports on Bud's LS1 look the same or slightly larger than the vans..meaning similar cooling drag...meaning similar HP/Speed requirements....which means that the numbers here would approach stationary diesel BSFC if true....which is why they do not seem credible.
My guess is that the turbo STI does very well at high DA, but if you have achieved a quantum leap at cooling drag (which would be evidenced by better FF/AS numbers in the 8,000 DA levels), I suspect you would be posting that long before now.
Anything hs less drag at 17,000 feet than it does at 5,000 feet. Heck, a 4x8 sheet of plywood has less drag at altitude than at sea level.
I have seen the numbers, but not the FF and altitude for the turbo STI...could you please post them?
The intake and exit ports on Bud's LS1 look the same or slightly larger than the vans..meaning similar cooling drag...meaning similar HP/Speed requirements....which means that the numbers here would approach stationary diesel BSFC if true....which is why they do not seem credible.
My guess is that the turbo STI does very well at high DA, but if you have achieved a quantum leap at cooling drag (which would be evidenced by better FF/AS numbers in the 8,000 DA levels), I suspect you would be posting that long before now.
Anything hs less drag at 17,000 feet than it does at 5,000 feet. Heck, a 4x8 sheet of plywood has less drag at altitude than at sea level.
Well this is just like old times except George isn't here.
I think Randy posted all the numbers here- search STI. The Sube gives best cruise performance at altitude- not at 8500 feet like a Lycoming, just the nature of the beast. Any Lyco powered 7As doing 213 knots at 8000 feet on 11.8 GPH? The best response I got was with an RV8/ IO-360- 191 knots on 9.6 gph, little doubt an 8 has less drag than a 7A.
I don't know what to attribute the performance of Randy's airplane to but there are only two possibilities as I mentioned- prop efficiency or cooling drag since the rest is stock 7A. In general terms, a turbo engine will always perform better at altitude than an atmo engine, no secret there, air is thinner and FF stays about the same. A good reason why turbos rule!
The inlet size has little bearing on drag so I won't agree with you on that one. It's what is downstream that counts- radiator and duct vs. cooling fins, no duct and lots of junk for the air to run into on a -10.
I too suspect FF figures on the LS engines are on the low side but will reserve judgment until some better calibrated test data comes in. Maybe it is best to look at it from another angle- even if Bill's FF numbers are off by 50%, it still performs as well as what Van's says a -10 will do with the Lycoming!
I seem to recall someone posting around 165 knots TAS on about 13 GPH. Any RV10 drivers want to pipe up here with their typical numbers?
I think Randy posted all the numbers here- search STI. The Sube gives best cruise performance at altitude- not at 8500 feet like a Lycoming, just the nature of the beast. Any Lyco powered 7As doing 213 knots at 8000 feet on 11.8 GPH? The best response I got was with an RV8/ IO-360- 191 knots on 9.6 gph, little doubt an 8 has less drag than a 7A.
I don't know what to attribute the performance of Randy's airplane to but there are only two possibilities as I mentioned- prop efficiency or cooling drag since the rest is stock 7A. In general terms, a turbo engine will always perform better at altitude than an atmo engine, no secret there, air is thinner and FF stays about the same. A good reason why turbos rule!
The inlet size has little bearing on drag so I won't agree with you on that one. It's what is downstream that counts- radiator and duct vs. cooling fins, no duct and lots of junk for the air to run into on a -10.
I too suspect FF figures on the LS engines are on the low side but will reserve judgment until some better calibrated test data comes in. Maybe it is best to look at it from another angle- even if Bill's FF numbers are off by 50%, it still performs as well as what Van's says a -10 will do with the Lycoming!
I seem to recall someone posting around 165 knots TAS on about 13 GPH. Any RV10 drivers want to pipe up here with their typical numbers?
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John- the subaru STI thread has the numbers, this page
http://www.vansairforce.com/community/showthread.php?t=39727&page=3
has one of the main posts on the top of the page. there might be more details in some of the other posts by Randy though.
also post #16 on page 2
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As you know, I love this stuff so I've been digging through my archives. Stanford U did some testing on the LS1 many years ago. Brake TE 34% max, BSFC at LBT mixture .39. Pretty darn good and the later LS engines are likely to be better with improved heads, cams and higher CRs. Certainly on par with Lycoming's best engines.
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Jamie
Well Known Member
While I certainly enjoy the technical engine discussion going on here, isn't this just a simple matter of:
1) Top off the airplane with fuel.
2) Fly four-way GPS runs at various power settings.
3) Enter data into this spreadsheet.
4) Fill the tanks again and compare against FF numbers.
1) Top off the airplane with fuel.
2) Fly four-way GPS runs at various power settings.
3) Enter data into this spreadsheet.
4) Fill the tanks again and compare against FF numbers.
Is it possible his AS was in MPH instead of Knots? ~12gph for 185mph on a smooth day sounds within the realm of the possible LOP.
What about it gipsowh?
David-aviator
Well Known Member
As fuel consumption goes, much better. My engine came in at .51 on the Barret dyno. But we must not forget an air cooled engine uses some fuel for cooling. The LS engines will have a better BSFC with liquid cooling. The trade off is cooling drag with the radiators. My Subby definitely needed larger rads and that would have meant more frontal area. The Lycoming does appear to burn more fuel down low for a given speed, but it does not have any cooling issues. Up high it is doing better. By the way, it cranks out 172 KTAS on 12.2 gph at 8000'.
I am impressed with the basic performance numbers of the LS engines. I did a BSFC calculation on a LS3 last evening using HP/fuel flow numbers published on the Vesta site and they came in at like .31 at low power and .39 at 275 HP. If those numbers showed up on a dyno, I would really be impressed.
Has the installed weight of the LS1 when published?
Jconard
Well Known Member
Thanks,
hadn't been on the site for a while, too busy flying. The Speed/FF numbers are similar and a little lower than I am getting with an O-320/WW 151 prop on an RV-7. But in all fairness, I have a pretty light plane and a sam james cowl, and a tailwheel. On the other hand I have not put the upper intersection fairings on and have a three blade prop.
My conclusion is that there is no delta of cooling drag/prop efficiency. Rather, we are simply witnessing the benefit of turbo horsepower at higher altitudes in thinner air. Still, it seems to be about as good, if not better than any other subie install in a 7A.
It is also apparent that a big factor of success is the use of a dedicated, bracketed engine management approach. The discreet, pre programed maps with (i am guessing) some trim knob eliminates alot of unpredictable variables that exist in auto computers.
As to the LS1....great engine, I would love to do a miata project with one. Time will tell how it does, but Bud certainly has the integrity and real world experience with the approach to make it work. I also think his approach to have a pretty fixed and repeatable design will pay benefits to customers as it will allow a knowledge base to develope that is applicable across the install base.
I still believe that in an aircraft approach, the GM computer approach is unnecesary...why not istall the LS1 with an airflow performance injection, and MSD mag or direct fire system...much less complex, much cleaner intake (think off shore boat racing where AFP is often used) and for steady state aircraft use, I bet the performance would be as good or better.
hadn't been on the site for a while, too busy flying. The Speed/FF numbers are similar and a little lower than I am getting with an O-320/WW 151 prop on an RV-7. But in all fairness, I have a pretty light plane and a sam james cowl, and a tailwheel. On the other hand I have not put the upper intersection fairings on and have a three blade prop.
My conclusion is that there is no delta of cooling drag/prop efficiency. Rather, we are simply witnessing the benefit of turbo horsepower at higher altitudes in thinner air. Still, it seems to be about as good, if not better than any other subie install in a 7A.
It is also apparent that a big factor of success is the use of a dedicated, bracketed engine management approach. The discreet, pre programed maps with (i am guessing) some trim knob eliminates alot of unpredictable variables that exist in auto computers.
As to the LS1....great engine, I would love to do a miata project with one. Time will tell how it does, but Bud certainly has the integrity and real world experience with the approach to make it work. I also think his approach to have a pretty fixed and repeatable design will pay benefits to customers as it will allow a knowledge base to develope that is applicable across the install base.
I still believe that in an aircraft approach, the GM computer approach is unnecesary...why not istall the LS1 with an airflow performance injection, and MSD mag or direct fire system...much less complex, much cleaner intake (think off shore boat racing where AFP is often used) and for steady state aircraft use, I bet the performance would be as good or better.
You read it right
All,
Interesting comments by everyone regarding these PRELIMINARY numbers. Airspeed is true airspeed in knots according to my GrandRapids EFIS. They are not 3 or four-way legs with winds computed by a spreadsheet. Jamie, cool spreadsheet by the way.
Still working the issue to get the numbers labeled FINAL when I have time. Breathe in, breathe out, move on.
All,
Interesting comments by everyone regarding these PRELIMINARY numbers. Airspeed is true airspeed in knots according to my GrandRapids EFIS. They are not 3 or four-way legs with winds computed by a spreadsheet. Jamie, cool spreadsheet by the way.
Still working the issue to get the numbers labeled FINAL when I have time. Breathe in, breathe out, move on.
Kevin Horton
Well Known Member
Yes, but I'd make a couple of minor adjustments.
1) If you intend to do quite a bit of performance testing, to quantify the effect of various improvements, you would spend a lot of time flying a four-way GPS run at each test condition. It is more efficient to invest a flight or two to determine the error in the airspeed indication system. Then, when doing performance testing, you only need to spend long enough at each test condition to record stabilised IAS, OAT and altitude, engine parametres, fuel flow, fuel quantity. After landing, you correct the IAS for the errors you determined during your airspeed system calibration flights, to get CAS. Then you use OAT and altitude to convert CAS to TAS.
2) It is hard to accurately fill the tanks to the exact same quantity every time, so the fuel used based on fuel pump readings could be off a bit if you look at it one flight at a time. To get a good handle on fuel flow accuracy, ideally you would accumulate data over several flights. E.g., sum the fuel used calculated by the fuel flow system over five or ten flights, and compare that to the sum of the fuel added after those flights.
Might want to us IAS instead of True - for a normally aspirated engine you should get nearly identical results at all altitudes for the same given power setting (assuming CS prop), with a small dropoff at altitude for prop inefficiency.
I agree with Kahuna that the fuel flow for speed is unlikely even for a modern engine - probably just needs something calibrated.
Don't be afraid to publish your numbers though - they will make sense once you track down all the variables!
Kahuna
Moderatoring
I have found that FF accuracy can only be calculated accurately over ~80 gallons. Certainly not one tank. I have made several adjustments over a 100gallon interval with positive results. A little chart in the cockpit with columns for data. Start with a top. Keep topping. Try and burn 3/4 of a tank per fill up. After passing 80 gallons of fill ups, you have decent data. Then calibration can take place. Then redo. When your within one gallon over a hunded interval your in good shape. My last data card put my 123 gallon interval at .4 gallons. I made a sensor calibration change and have not done another interval since. Im probably due for another. I live by my FF numbers as my inflight tank reads on the cap sensors are not very accurate even after MANY attempts at calibration.
Columns:
Gallons Computer said I used, Gallons Actually Used, Diff
Columns:
Gallons Computer said I used, Gallons Actually Used, Diff
Kahuna
Moderatoring
What?
I completely disagree. Its very important that envoirnmental factors be included for any published data to be useful. Further, those factors should also be well calibrated over time for the data to be useful. Should there be any comparison in data across platforms, it must be calibrated and normalized, which the DA and TAS #'s do for us. Flying a DA, comparing ITAS #'s with cross tracked GPS, and calibrating those sensors to get that ITAS number to match the cross tracked GPS, is the only way to have any meaningful dialogue on this subject.
Gotta get apples to apples.
TAS for sure here and I totally agree that you need to run a few tanks through to get accurate results. I also suggest topping tanks and running taxi, TO, climb and descent on one tank and cruise on the other. Much easier to get true FF numbers against the clock. It took me about a year of tweaking to get my FF constant set right- of course I was busy doing a dozen other things at the time.
Calibrate the glass with four way GPS runs first.
John, I disagree with regards to your performance vs. Randy's Subaru. Randy also did not have intersection fairings in place and his airplane is heavy. This speed was set at 8000 feet so it's apples to apples. He has a "slow" 3 blade MT prop. I'm looking at the high speed data point here. If there are any Lycoming powered 7As out there which can true 213 knots on 11.8 gph at 8000 feet, please step up here.
The Vesta FF data is nonsense IMO. We know for sure that no SI engine is going to deliver SFCs of .31. The very best are in the .37 range.
Bill is probably regretting posting preliminary numbers now. Sorry for jabbing you for numbers. A lot of interest in how this package performs and it is way cool.
Calibrate the glass with four way GPS runs first.
John, I disagree with regards to your performance vs. Randy's Subaru. Randy also did not have intersection fairings in place and his airplane is heavy. This speed was set at 8000 feet so it's apples to apples. He has a "slow" 3 blade MT prop. I'm looking at the high speed data point here. If there are any Lycoming powered 7As out there which can true 213 knots on 11.8 gph at 8000 feet, please step up here.
The Vesta FF data is nonsense IMO. We know for sure that no SI engine is going to deliver SFCs of .31. The very best are in the .37 range.
Bill is probably regretting posting preliminary numbers now. Sorry for jabbing you for numbers. A lot of interest in how this package performs and it is way cool.
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Jconard
Well Known Member
At 169 knots TAS @ 4500'. 3800 RPMs and 38" MAP measured exactly 8.9 GPH. I flew exactly 1 hour under the same conditions on this test, then switched tanks, descended and measured the amount to fill.
Call it 194 MPH TAS, 4500' @ 8.9 GPH
At 140 Knots TAS @ 4500', 3800 RPMs and 28" MAP fuel burn came to 6.16GPH. I flew under the same conditions for exactly 30 minutes for this test. Conditions were a bit turbulent along the Cascade Mountains with a South wind blowing.
Call it 161 MPH TAS, 4500' @ 6.16 GPH
geez ross, these are the numbers from the thread I was talking about...I did not see the thread of 213 knots at 8,000 feet on 11.8 gph but to be frank, that is 244 mph, which would take in the neighborhood of 250 horsepower based on Van's design numbers. If you can produce that much power on 11.8 gph it would be truly impressive, and again a BSFC number at or better than stationary diesel....so lets call that number interesting. Perhaps a neutral genius like Kevin can double check my math here, but it seems like we have discovered net negative drag....
Call it 194 MPH TAS, 4500' @ 8.9 GPH
At 140 Knots TAS @ 4500', 3800 RPMs and 28" MAP fuel burn came to 6.16GPH. I flew under the same conditions for exactly 30 minutes for this test. Conditions were a bit turbulent along the Cascade Mountains with a South wind blowing.
Call it 161 MPH TAS, 4500' @ 6.16 GPH
geez ross, these are the numbers from the thread I was talking about...I did not see the thread of 213 knots at 8,000 feet on 11.8 gph but to be frank, that is 244 mph, which would take in the neighborhood of 250 horsepower based on Van's design numbers. If you can produce that much power on 11.8 gph it would be truly impressive, and again a BSFC number at or better than stationary diesel....so lets call that number interesting. Perhaps a neutral genius like Kevin can double check my math here, but it seems like we have discovered net negative drag....
Bill,
Just wanted to say thank you for being willing to publish your "preliminary" numbers in response to everyone's requests for some fuel burn information. You have one of (if not the only one ) V8 powered RV10 that is past the 40 hour flyoff period and there is a lot of interest in the package.
Look forward to your future reports.
Regards,
Bill
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Your math is about right, say 240 hp to do this speed at around 8000 feet- with an air cooled engine and standard Hartzell prop.
I told Randy initially it seemed too good to be true but he followed all the proper methodology to the tee and repeated several times to check the FF and the TAS, even not believing the gas pump meter finally and re-checking with Jerry cans. Randy is a straight arrow type who wants to know the real numbers. He is making mods now but welcomes any Lyco powered RV to fly against him to verify. Again, I don't believe the engine is making anywhere close to 240hp at this power setting so, I'll repeat for about the third time here- prop, cooling drag, jet thrust???? He has a fantastic package here. To be fair, the 11.8 GPH figure came from the SDS FF function after tweaking the calibration number through many other fly and fill tests. Could still be off a bit at the higher injector duty cycles due to the delta in response time vs. on time at these power settings. Nonetheless, Randy has by far the fastest stock airframe 7A around to my knowledge and he's certainly not burning 14-15 GPH to do it.
Bring the altitude up and the turbo Subaru gets even better mileage as TAS increases and FF stays about the same. This is where it really shines against a Lycoming.
I've read up on the Robinson LS conversions as well today and the V8 delivers substantially better MPG figures than the Franklin it replaced as tested on the same airframe before and after- 12.9 vs. 10.
Gary Spencer's race winning Long EZ with the Ford V8 did 200mph on 6 gph vs. 175mph on 6 gph with the O-235 Lycoming.
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David-aviator
Well Known Member
The exuberance regarding the success Randy has had with the STI is understandable, and an unquestioned achievement, but it needs to be tempered just a bit.
Randy has had 4 engine out landings with the STI and the last one really scared him. I congratulated him on the successful flights and that particular landing but also commented that he has been very lucky.
The STI is performing well and will smoke by a Lycoming but until it becomes as reliable as a Lycoming, it is not an apples to apples comparison.
Not many pilots enjoy taking off and wondering if they dare leave the traffic pattern on a day to day basis, fastest airplane or not.
For a comparison of BSFC numbers here at UBC we have received a Cummins 400 HP ISX Diesel engine. The fuel flow specs for this engine are. 222 mm^3 per injection at 400 HP and 2000 RPM. I did the calcs and this turns out to be 0.36 BSFC (approx. 22 USgal/hour) when converted to US conventional units. Getting sub 0.4 SPFC with a SI engine is REAL tough, if meeting NOx requirements Impossible.
Bob Parry
Really not fair to just throw out "He's had four engine out landings" and leave it at that. Without some details on what was the problem a certain number of engine out landings doesn't mean his engine package is less trustworthy than a traditional airplane tractor engine. It doesn't mean much that i can tell, other than his engine stopped 4 times in flight unplanned.
The local high performance kit manufacturer had an engine out landing with a traditional continental, guess what the stated fault was? poor overhaul shop. Does that mean the airframe doesn't do the published numbers? No! It means there was a serious problem with keeping the engine running.
For your statement of a apple to apple comparison to be valid we'd need thousands of subaru powered planes flying and be able to compare numbers for fleets. that probably won't happen. For now FF and TAS/ CAS are good.
I think the guys with a subaru or LS1 or even the rotary engine deserve our respect and support for going where very few have gone before (successfully). I think that will be one of the greatest advancements in experimental aviation in our time- new engine technology.
Mike S
Senior Curmudgeon
Right on...
Darylat8750ft
Member
In assuming SFC numbers we all seem to be assuming total drag to be the same as an air cooled engine. Is it possible that the prop cowling interference and total cooling drag is enough better to account for some if not most of the performance (as related to SFC) improvements?
Daryl
Daryl
David-aviator
Well Known Member
David-aviator
Well Known Member
Ross, are you sure it is 213 knots and not 213 mph?
My -7 will do 172 KTAS at 8000' at 12.2 gph. That's 198 mph. If Randy did 213 knots, that's 41 knots (47 mph) faster!
Hey, if you know of some STI engines someone wants to give away, let me know.
I'm serious.
David-aviator
Well Known Member
I found the original "STI Rules the sky" report of last February 19....here's part of it.
...Then I finally decided to go ahead and turn up the boost and RPMs
some more and see what happens. I guess I got a little busy watching
the wrong gauges for a minute and before I knew it I had blown right
on through VNE! I performed a damned accidental flutter test today.
I got the power set at about 4750 RPMs and 47" MAP and by the time I
took a photo of the EFIS it registered that I was well above VNE. I
don't care to post the actual speed here as this was stupid move on
my part and I would rather not advertise it. I will admit that the
speed got considerably above the 200 knot mark, and there was more
boost and RPMs left to play with. So that is enough of that! This
STI doesn't care about cooling drag and all that stuff, it will just
blow right through VNE if you care to become a test pilot. I won't
be doing that any more, I promise
Oh yea, fuel flow readout during my little flutter test was at 71 lbs
per hour, or about 11.8 GPH.
I suspect the TAS was 213 knots. The STI does indeed rule the sky, at least it did that day.
dd
Hmmm...........
Seems like this thread has been hijacked! Initial topic was Bud Warren's LS1 Geared Drive. If Bill's numbers are just 75% accurate, it will be a major feat for experimental aircraft. If reliability holds up, it will be a major accomplishment for Bud, (I personally think the drive will). I have watched this development very closely on a daily basis for the last two years. What hasn't been mentioned is Bud's new prototype drive for the EJ25 Sub, it is quietly being tested on an RV9A, with Bud's cooling system. The drive has had no problems. It bolts on to an Egg setup with literally no mods. to the mount. What is really great about it is it uses Bud's cooling system and temps are way down, while performance is way up.
Bud told me once "I can do anything", I beginning to believe him!
I predict in the next six months Bud will be covered up with orders for RV10 FWF Packages, but what do I know, I'm a Lycoming guy.
Seems like this thread has been hijacked! Initial topic was Bud Warren's LS1 Geared Drive. If Bill's numbers are just 75% accurate, it will be a major feat for experimental aircraft. If reliability holds up, it will be a major accomplishment for Bud, (I personally think the drive will). I have watched this development very closely on a daily basis for the last two years. What hasn't been mentioned is Bud's new prototype drive for the EJ25 Sub, it is quietly being tested on an RV9A, with Bud's cooling system. The drive has had no problems. It bolts on to an Egg setup with literally no mods. to the mount. What is really great about it is it uses Bud's cooling system and temps are way down, while performance is way up.
Bud told me once "I can do anything", I beginning to believe him!
I predict in the next six months Bud will be covered up with orders for RV10 FWF Packages, but what do I know, I'm a Lycoming guy.
I might mention that modern SI DI engines from GM, BMW and Lexus have all posted sub .4 SFCs in the last few years and are very close to some diesels at WOT. In particular the BMW Valvetronic equipped engines even do well at part "throttle" (they don't have throttle plates).
To the diesel guys out there, SI aviation engines like the R3350TC were capable of sub .38 SFCs back in the 1950s! A Conti 550 with GAMIs running LOP can achieve these figures as well. Not hard or new technology.
Yes, this thread has drifted back into the generic liquid cooled vs. air cooled theme again. Maybe we can post the STI related back in that thread?
I do think Bud can make the LS work well and once proven more, he will take a number of orders away from Lycoming. Competition is always good.
Power to ya Bud and I hope Bill will still post new data when available after all this thrashing.
To the diesel guys out there, SI aviation engines like the R3350TC were capable of sub .38 SFCs back in the 1950s! A Conti 550 with GAMIs running LOP can achieve these figures as well. Not hard or new technology.
Yes, this thread has drifted back into the generic liquid cooled vs. air cooled theme again. Maybe we can post the STI related back in that thread?
I do think Bud can make the LS work well and once proven more, he will take a number of orders away from Lycoming. Competition is always good.
Power to ya Bud and I hope Bill will still post new data when available after all this thrashing.
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Kahuna
Moderatoring
Gear Collapsled
Bill can you tell us what happened?
======
IDENTIFICATION
Regis#: 730WL Make/Model: EXP Description: RV-10
Date: 07/16/2009 Time: 1729
Event Type: Incident Highest Injury: None Mid Air: N Missing: N
Damage: Minor
LOCATION
City: CONROE State: TX Country: US
DESCRIPTION
AIRCRAFT ON LANDING, GEAR COLLAPSED, CONROE, TX
INJURY DATA Total Fatal: 0
# Crew: 2 Fat: 0 Ser: 0 Min: 0 Unk:
# Pass: 0 Fat: 0 Ser: 0 Min: 0 Unk:
# Grnd: Fat: 0 Ser: 0 Min: 0 Unk:
WEATHER: SPECI 161745Z 00000KT 10SM SCT 045 34/22 A3003
Bill can you tell us what happened?
======
IDENTIFICATION
Regis#: 730WL Make/Model: EXP Description: RV-10
Date: 07/16/2009 Time: 1729
Event Type: Incident Highest Injury: None Mid Air: N Missing: N
Damage: Minor
LOCATION
City: CONROE State: TX Country: US
DESCRIPTION
AIRCRAFT ON LANDING, GEAR COLLAPSED, CONROE, TX
INJURY DATA Total Fatal: 0
# Crew: 2 Fat: 0 Ser: 0 Min: 0 Unk:
# Pass: 0 Fat: 0 Ser: 0 Min: 0 Unk:
# Grnd: Fat: 0 Ser: 0 Min: 0 Unk:
WEATHER: SPECI 161745Z 00000KT 10SM SCT 045 34/22 A3003
Radomir
Well Known Member
That blows... may have been minor damage until firemen came near it??
http://www.myfoxhouston.com/dpp/news/local/090716_experimental_plane_crash
http://www.myfoxhouston.com/dpp/news/local/090716_experimental_plane_crash
Gear Collapse Incident
Yes, its true, N730WL was damaged Thursday afternoon during a test flight and subsequent emergency landing. Pilot, Bud Warren and I were taking the 10 for a flight around the airport to check out a high operating temperature problem. We took off after a long taxi and climbed normally, however the engine temperature kept climbing even after leveling off. For unknown reasons the engine seemed to quit making power. Bud skillfully banked back toward the runways. Not a good situation. A discussion with Bud today leads me to believe that the high engine temperature may have exceeded an operating parameter in the ECM and the engine reverted to a low power setting. This has yet to be confirmed but obviously needs to be addressed if this is indeed the problem.
Bud managed to get the airplane back to the airport sacrificing altitude and speed without stalling. Incredible job by Bud to get us back to the runway. However, once over the runway, we were too slow and the plane mushed onto the runway rather hard. We bounced and skidded to a stop on the collapsed main gear. Fortunately, there was no fire and Bud and I were able to get out of the 10 without any injuries, Thank God.
Unfortunately, there was considerable damage to the main landing gear and the prop was destroyed. The steps kept the bottom of the fuselage off the runway while we skidded, so no noticeable damage to the fuselage skin or tail. The wings didn't hit the ground but there is some minor damage from the gear folding up. I haven't looked at the landing gear mounts yet or the spar. So I don't know at this ten seconds the full extent of the damage.
This project has been five years in the making and this is a tough pill for me to swallow. I really appreciate the concerns voiced. Will try and keep you posted on any new developments or findings.
Yes, its true, N730WL was damaged Thursday afternoon during a test flight and subsequent emergency landing. Pilot, Bud Warren and I were taking the 10 for a flight around the airport to check out a high operating temperature problem. We took off after a long taxi and climbed normally, however the engine temperature kept climbing even after leveling off. For unknown reasons the engine seemed to quit making power. Bud skillfully banked back toward the runways. Not a good situation. A discussion with Bud today leads me to believe that the high engine temperature may have exceeded an operating parameter in the ECM and the engine reverted to a low power setting. This has yet to be confirmed but obviously needs to be addressed if this is indeed the problem.
Bud managed to get the airplane back to the airport sacrificing altitude and speed without stalling. Incredible job by Bud to get us back to the runway. However, once over the runway, we were too slow and the plane mushed onto the runway rather hard. We bounced and skidded to a stop on the collapsed main gear. Fortunately, there was no fire and Bud and I were able to get out of the 10 without any injuries, Thank God.
Unfortunately, there was considerable damage to the main landing gear and the prop was destroyed. The steps kept the bottom of the fuselage off the runway while we skidded, so no noticeable damage to the fuselage skin or tail. The wings didn't hit the ground but there is some minor damage from the gear folding up. I haven't looked at the landing gear mounts yet or the spar. So I don't know at this ten seconds the full extent of the damage.
This project has been five years in the making and this is a tough pill for me to swallow. I really appreciate the concerns voiced. Will try and keep you posted on any new developments or findings.
Kevin Horton
Well Known Member
Does the ECM have to be mounted ahead of the firewall? I know they do it that way with cars, but cars generally run at lower average power than aircraft, so the engines make a lot less heat. And the consequences if a car engine stops because the ECM overheats are relatively minor compared to the consequences from the same event in an aircraft.
It would be nice to have some sort of limp home mode if the ECM fails too, or a second ECM, with its own sensors and power supply.
Kevin, I don't think he was talking about the ECM overheating but the ECM sensing the engine was overheating and basically sending it into limp home mode. The problem being limp home mode probably doesn't generate enough power to keep the plane flying. I think Bill doesn't know if there is such a thing on this computer though.
Kevin Horton
Well Known Member
Ahh. Makes sense. An automotive limp home mode might offer quite a low power - more than enough for low speed ops in a car, but no where near enough for an aircraft. Thanks for the educated guess.
Too bad GM won't share the detailed design of the ECM. I've done quite a bit of FADEC testing on aircraft turbine engines. We force the manufacturer to do a detailed analysis of the effect of all possible correct and incorrect inputs from each sensor, plus all possible failures of each thing that is controlled by the FADEC. This is followed by a long test stage on a test rig to validate the results of the analysis, followed by a running a sub set of the tests on the aircraft. This process has invariably revealed some cases where the expected response to some types of failures was not acceptable, or cases where the actual response to the failure differed significantly from the predicted response. But if the ECM is just a "black box", with no knowledge of exactly what it does, then you are leaving yourself wide open to cases where the assumptions that underly the design of the automotive ECM are not valid in the aviation world.
I think if you want a reliable system, you need to have simple electronic controls designed specifically for aviation use, and where you are certain that the system has been fully analyzed and tested in an airborne environment.
Just about any of the top Vette shops can use EFILive or any of the other tuner software programs to disable limp mode on the LS series ECMs.
I think in that situation, I would like to see the ECM keep the engine running, and use the "limp home" mode activiation criteria to simply light a warning light on the panel - something along the lines of "ENGINE FAILURE IMMINENT". This would be akin to a chip detector on a helicopter gearbox - meaning get it down NOW while you've still got a little power left, knowing full well you are sacrificing the engine to save your skin.
