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I actually did ask the FAA (or one of its representatives) this question a few years ago when I was part of the ASTM committee coming up with industry standards for meeting the proposed Part 23 rewrite. The "reason" was exactly what I posited above--"we assumed all jets would be high performance complex heavy machines that required special training", and then when someone crashed an F-86 into an ice cream shop it further cemented that idea. They outright stated that something like a SubSonex or the jet Cri-Cri never crossed their minds. However, pointing out that the original assumptions are no longer valid apparently holds no weight with the FAA. I asked why we carried over the language that position light lenses needed to be "flame resistant" but landing and taxi lights need only "not cause a fire hazard in any configuration". The response was "we agree that doesn't make sense and we don't know why it's written like that, but we aren't going to change it". I've received similar responses to other inquiries--among others, I asked why the aircraft and airman databases were publicly searchable while motor vehicle registration and driver's licenses were considered sensitive "need-to-know" information. The response, egregious misspelling included, was simply "Are databases are public for safety" :rolleyes: |
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But I know the guy leading the effort to make this more liberal is tenacious - so we'll see where it goes. |
First deposit from an RV builder
I am pleased to announce that we have received our first deposit from a dedicated RV builder.
I would like to thank him for his support for our engine and express my own admiration for the initiatives he is proposing to integrate the engine into his aircraft. His set-up will certainly gather attention in a very positive way and he should end up with a very high performance and safe aircraft. Dave |
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I gotta say, dealing with those FAA guys on the ASTM committee was like repeatedly smashing my head into a heavy-duty welding table (or was that what I wanted to do to them?). There was one guy who didn't understand that a pressurized twin was not representative of the average "light personal aircraft". I think a great example of the mindset prevailing there is "Rumor has it that 12,500 lbs was on the 3rd tablet that Moses dropped and broke on the way down from the mountain." |
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Dave |
very interesting
I remember being quite enthused back in 2002 about the Affordable Turbine Power (ATP) turbine. Later known as Innodyne, it struggled awhile, had ups and downs, and was dead by about 2005 or 2006.
Then there was someone at AirVenture (perhaps SNF) about 5 or so years ago for a couple years, doing development on a turbine powerplant. I believe their test bed was an RV-10, but I'm not sure on that, as I didn't document it much. I don't remember the name. I know I took pictures of it, but I can't seem to find them. I saw them a couple different years, then they faded away. I think the second time I saw them, I didn't see much difference from the first time I saw them. I wish you well on your venture, and hope you have more success than your predecessors. |
Dave--interesting concept! I know the other turbine company that did an install in an RV is having some supply issues for that engine. We did some hoses for it.
Sounds like a fun out of the box project to work on, like we did for the Continental Diesel project. We'd be glad to help out. Tom |
Turbine powered RV-10
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There is an RV-10 w/ Turbine that is now flying. They bought a buddies RV-10 and showed it off at SNF a few years ago w/only his fuselage; but have subsequently finished it up and I know are flying it now since they gave him a ride in it last month when he was in Florida. See Turbine Solutions Group: http://www.turbinesolutiongroup.com/tsg_RV10_kit.htm Doug Lomheim RV-9A Mazda 13B/FWF |
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https://www.facebook.com/Turbine-Sol...9158212429254/ |
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Brian---its flying and they have a few other conversions they were working on. I think I remember them telling me about some changes in the engine manufacturer that was slowing progress some.
Tom |
Any recent developments on this?
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Tommy---the 200 HP version is on the drawing board/solidworks CAD---or whatever the term is now for 'cyphering' about it. We talked with Dave Limmers a few months ago, and again in an email about 6 weeks ago asking for some data. They didnt have that data at that time. WE have a RV14 client that is impatiently waiting on things to progress so he can finish some things.
Dave might chime in here, but I dont know of any progress lately. Tom |
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I've read this entire thread and your website, and if it is there I can't find it. Are you anticipating that these engines will maintain full rated hp, and if so to what altitude? Or will they lapse like normally aspirated engines? It makes a huge difference - 120hp flat rated out-performs a standard IO-360 (180hp) above 12,500 density altitude, sometimes steady wins the race. |
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Fuel flow at 20,000? @ 137hp is projected to be around 9.5 gph. A 150hp cruise at 10,000? on an ISA day will yield a fuel flow anticipated to be around 11.4 gph. These are preliminary theoretical numbers that have yet to be validated. In around 9 months, I hope to be able to provide validation (or correction if necessary!). The first RV that our engine will go into will be an RV14, as mentioned earlier in this thread. That is likely to be in around 15-18 months from now. The owner of that aircraft will be working with us to provide accurate numbers to the RV fraternity to enable RV builders to make an informed decision about their choice of powerplant. We are excited to work with this builder to get his Turbine RV airborne as soon as possible. Dave |
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I've got a deposit in for one of these engines.
Debating about building a RV-14 around it... Or, maybe a Velocity Twin. :p |
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Interestingly, the Twin could probably be safe with two of the 120hp models. Based on his numbers for the 200, I would expect the 120 to still provide 100hp up to 10,000', which ought to be enough to provide single engine climb even up there. Big weakness of turbines is that efficiency usually goes way down below 85% power or so, so pulling back the throttle doesn't really save that much and two 120s would be running at just about optimum producing 200hp continuous at 10k'. |
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While they have "limited" to 200 kts historically, the airframe might actually be able to take advantage of the additional thrust available through a turbine engine. No one will really know until it's done. Of course, Vmc will probably creep up to be a real thing for the airframe instead. |
I'd love to put a turbine in the 14A I'm building. For me its just about the safety.
The W&B issues is what kills it for me. I don't want to have a special cowling an extra 2' long while my nose gear sits on the firewall. Whatever the engine mount is will have to have a place for the nose gear? Although you could just mount the engine as close the normal length as possible so you can use the stock cowling and have a 1/2" steel firewall to make up the weight. :D |
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Turbine Aeronautics update
Hello to all readers again.
With some recent discussion on this thread, I thought it would be a timely moment to update folks on progress. I'd like to start by saying that the development of a turbine engine is a major undertaking in many respects, particularly for one that offers the performance and features that we feel are necessary to be successful in the market. The technical challenges that must be resolved are not to be considered lightly. We are incorporating some innovative technical features into our engines to ensure that they meet the fuel efficiency and reliability expectations of the kit aircraft builder. As standalone components, the design of these components is challenging. When combined with the other engine components, the challenges are more demanding because the performance of one component affects the performance of other components. What this means is that a lot of the design process is iterative. For example, whenever we modify the recuperator design, we must redesign the aero components (compressor, turbines etc.), which means that when the recuperator designer tweaks the recuperator, the results need to go to the aero designer to tweak the aero components, and those results need to then go back to the recuperator designer for him to re-tweak etc. This is just an example of the many iterative processes that need to be done to ensure that all our components achieve the correct design parameters, when combined into the final design. This iterative process, combined with the technical complexity of the design of the many components has resulted in a shift to the right in our original timeline. Fortunately, the shift isn't too far to the right and we are very pleased with the progress on our program. We are currently in the detailed design phase for many of our components. The good news from the work done to date is that our performance targets are still on-track. >200hp for a sea level takeoff on an ISA day; 180hp at 10,000' ISA conditions 180ktas should yield a Specific Fuel Consumption of marginally under 0.50 lbs/hp/hr and it is looking like this SFC may be achieved down to 150hp, same conditions. We are still on track for the engine to offer around 140hp at 20,000'. Our Arion Lightning testbed aircraft has been built and will shortly be shipped to Australia for installation of the first airborne test unit, when it becomes available. We plan for this to be in around 12-15 months time from now. We remain committed to bringing our engines to our primary market, being the recreational aircraft market. This is our sole focus and will remain so until we deliver our engines to the builders like you and me. My personal Lightning Bug and White Lightning projects are just waiting for the 200hp engine. As such, I think I am more motivated than anyone to see the availability of these engines! For Tom at TSFlightlines, specific details about our fuel delivery system should be available within the next 3 months. I will get them to you asap. I spoke with your RV14 builder this morning to update him on progress. For MercFE, the guys at Velocity are watching our progress with interest and we remain engaged with them. Dave |
.5 BSFC will be very impressive at this scale if you can do that and that accomplishment would go a long ways towards wider acceptance of the engine in this market.
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We were not prepared to proceed with the development program if we couldn't get the SFC to less than 0.55 lbs/hp/hr so that was our initial target. Indications are that we can do a little better than our target, but time will tell. In 10 months when its on the test stand and we have verifiable numbers, that will be crunch time for us. If we can demonstrate that level of performance, we hope that we can convert the LyConti customers to turbine power. |
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Typically "plastic planes" are less susceptible to flutter than aluminum, I think it has to do with dampening due to elasticity - but nothing is "safe" until proven so. Absent a flutter issue, there's no real reason you couldn't drive a Velocity upwards of 300KIAS if you have enough horsepower. They are really rather tough in the +/- g's department and should handle turbulence well also. |
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We are also hoping to save well more than 100lbs of weight over the piston engine competition. We will advise the public of our test results with pump diesel in due course. We believe that we have an additive solution to resolve blockage of injectors, but this will all be tested in due course. |
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Vans' aircraft are all TAS limited, so I'll use a Twin Velocity as an example. And a BIG caveat - I am using napkin numbers and assumptions which may be flawed, so please correct me if I'm way off base! From their web page with two 200hp Lycomings they predict a cruise speed of 215 KTAS @ 75% power (one presumes at or near 7,500' since that is about how high you can go and still generate 75% power in a normally aspirated Lycosaurus). Replacing the two Lycosaurus engines with your turbines and assuming 150hp / engine @ 17,500' should realize about 288 KTAS (same horsepower, add roughly 3% per 1,000'). That is VFR / Cannula O2 territory. Above that your engines presumably lapse in power at a similar rate to pistons, but for economy cruise you could don the mask and climb to FL250 where you ought to get just about the same true speed but only be producing 100hp per engine with the efficiency still being quite high. If you miraculously still got 0.5pph/hp up there that would be around 15-16gph @ 330mph (not knots) TAS, or a bit over 20mpg in a high capacity 4 seat airplane. 16gph from a 100 gallon tank is over 6 hrs (barely); in that time you could travel roughly 2,000 miles nonstop (no wind, 15 minutes of gas left). Admittedly most folks don't want to don the mask. Still, that would be a rather remarkable aircraft. And then of course, if you just add a small bleed air port, you could add pressurization, heating, air conditioning... :D Anyway, please don't let me distract you from your development efforts. Lots of us out here are cheering for your success! |
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Umm...
"... And then of course, if you just add a small bleed air port, you could add pressurization..."
I know it was kind of TIC but there is substantially more to the design of a reliable, safe pressurized airplane than "just adding a small bleed air port"... |
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Not true
That "bleed air" can easily com from a turbo or supercharger.
Not that it matters where it comes from. It would still be a substantial project... |
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Raptor...
Love it...
Point is, there are many other considerations than just pumping air into a vessel. Some of the more important things like the cyclical loading on the pressure vessel and windows need to be looked at...how about door structure and latching mechanisms and window structures. If you think about it, even a low pressure differential can generate some really large forces within the structure. Not saying that it can't be done, only that there are lots of things to consider...it sure would be nice to be pressurized...and maybe a higher Vne, too... |
I don't even really mind the O2 mask in the flight levels, I've had my 9A up to FL210, what would really be nice would be a higher Vne and a turbonormalized engine - but that's really a different airplane now.
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Heck, I'd be thrilled merely to have a higher Vne. Just that.
Dave RV-3B, now working on the canoe |
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We don?t intend to offer a bleed port initially. We figure that not a high % of our customers will be pressurising their aircraft. Indeed, we optimised the engine for 10,000? because we feel that not many will likely go much higher. We suspect that 18,000? will be many folks limit where cannula oxy can be used and pressurisation is not a necessity. 140hp or thereabouts is still a fairly useful power at 18,000?. Dave |
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