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04-16-2017, 03:55 PM
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Join Date: Mar 2012
Location: Adelaide, Australia
Posts: 14
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Quote:
Originally Posted by BillL
Internal efficiencies, tip clearances, temps are all quite a challenge for small turbines. Good going guys - look to hear more.
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Hi Bill.
Thanks for the support. You are correct, those factors are a challenge but we have to work with them. However, technology/materials/manufacturing techniques are all much better than they were 10 years ago to the point where we stand a good chance of achieving our aims for the engines.
Dave
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04-16-2017, 04:03 PM
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Join Date: Mar 2012
Location: Adelaide, Australia
Posts: 14
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Quote:
Originally Posted by N941WR
That is my biggest issue with any new engine manufactures.
With no service history and a costly custom installation, they all seem to want to charge more for their engine than a comparable Lyclone.
It is as if the new engine manufactures do not understand the risk a builder is taking by installing their engine. That risk is both financial and physical.
If a new engine manufacture really wanted their engine out there, building time and reputation, they would offer the engine at the same price or less, and provide all the FWF parts at no charge.
Better yet, rather than sell to a new builder, they would contact a builder with a flying plane, document all the performance parameters, remove the old engine, install the new one, and run the same performance tests with the new engine.
Only then will you have a real apples to apples comparison of what the new engine does or does not provide in terms of performance and weight savings.
I realize that means the engine manufacture is taking a big risk but not nearly as much a risk as the builder.
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Believe me, as a builder myself, I hear you. No-one wants to take a risk, especially with a $45k investment.
We are in the fortunate position that a number of manufacturers have offered their support for our program in the form of offering aircraft to test/demonstrate/build hours on the engine. We have also had no shortage of builders who have offered the same with their own aircraft.
It is clear that there is intense interest in our engines and there are certainly some folks out there that see the benefits of our engines and are very excited about them. The onus is now on us to deliver the product, build a solid reputation for the engine and product support, and give the people what they want.
There will be apple to apple comparisons done when our engines are first delivered and installed. That will be the time that many builders become fully converted (or alternatively turned off if we have got it wrong!).
Dave
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04-16-2017, 04:08 PM
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Join Date: Mar 2012
Location: Adelaide, Australia
Posts: 14
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Quote:
Originally Posted by Snowflake
My concern with this would be the effect on CG. 250-300 lb off the nose of an RV means you have to move that lighter powerplant a looooong way out to balance everything again.
As a powerplant, it shows great promise for someone looking to design an airplane around it. 120-200hp are great ranges to carry two people aloft, for casual cruising around (120hp) or stellar performance (200hp) but to optimize it you'll have to start over and configure the airframe with the lighter powerplant in mind. An RV with the wing moved back, or the seating moved forward, could do it, but you're still looking at significant engineering.
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Hi Snowflake,
We have already had a few prominent airframe manufacturers express the desire to develop custom airframes to accommodate our engines. There is certainly one manufacturer who has the vision and drive to be involved with us during our developmental program to ensure that they have a new design customized airframe that can fully take advantage of the features of our engines, i.e. light weight and low frontal area etc. ready to launch soon after the engine deliveries start.
Dave
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04-16-2017, 05:33 PM
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Join Date: Nov 2006
Location: Savannah, GA
Posts: 1,029
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Quote:
Originally Posted by N941WR
That is my biggest issue with any new engine manufactures.
With no service history and a costly custom installation, they all seem to want to charge more for their engine than a comparable Lyclone.
It is as if the new engine manufactures do not understand the risk a builder is taking by installing their engine. That risk is both financial and physical.
If a new engine manufacture really wanted their engine out there, building time and reputation, they would offer the engine at the same price or less, and provide all the FWF parts at no charge.
Better yet, rather than sell to a new builder, they would contact a builder with a flying plane, document all the performance parameters, remove the old engine, install the new one, and run the same performance tests with the new engine.
Only then will you have a real apples to apples comparison of what the new engine does or does not provide in terms of performance and weight savings.
I realize that means the engine manufacture is taking a big risk but not nearly as much a risk as the builder.
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I'm sure the new engine manufacturers are fully aware and cognizant of the risks the early adopters are taking on.
The problem is that these alternative engines are typically being developed by smaller companies with limited budgets. It takes a lot of capital to develop and test a new engine or even completely adapt an existing one to a new purpose, and then set up a production line for the necessary special parts.
I'm sure if they had the money to do so (or a sugar daddy like Elon Musk) they would be quite happy to develop full all-in-one-box FWF packages and sell them at their desired final prices well under Lycoming rates. But I'd guess that most of these companies start selling engines when they do, and at the relatively "on your own" state of installation package, because they've been bleeding hundreds of thousands of dollars (if not millions) and they are probably desperate for some kind of cash flow just to keep the lights on a little longer.
That's why they follow the early adopter model that everyone else uses--they sell the first generation of the product (which isn't ready for the mainstream) to the tech-savvy users who are willing to pay a premium to have it first. Those sales fund refinement of the product and help bring the cost down for the rest of us.
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RV-7ER - finishing kit and systems installation
There are two kinds of fool in the world. The first says "this is old, and therefore good"; the second says "this is new, and therefore better".
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04-17-2017, 07:18 AM
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Join Date: Dec 2011
Location: Alpharetta, Ga
Posts: 212
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Quote:
Originally Posted by flyvulcan
Hi Snowflake,
We have already had a few prominent airframe manufacturers express the desire to develop custom airframes to accommodate our engines. There is certainly one manufacturer who has the vision and drive to be involved with us during our developmental program to ensure that they have a new design customized airframe that can fully take advantage of the features of our engines, i.e. light weight and low frontal area etc. ready to launch soon after the engine deliveries start.
Dave
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Hey Dave, Sounds like you guys have some interesting things going on.
Since you're already thinking outside the box, let me take it a bit (maybe more than a bit) further.
Since one of the issues is the light weight of these turbines. How about putting two engines under the cowl. They would both "feed" into a reduction gear box to turn the prop. Dual engine helicopters do it somehow.
Another issue with the turbines is high fuel burn, so you for sure wouldn't want two up there burning the whole flight. Just use both for takeoff. Then in cruise one would be shut down. Of course, in case of engine failure during cruise, the other could be restarted.
Engine use would be balanced so both would get equal use. This would extend TBOs for both engines, unlike a normal twin where both engines run simultaneously.
Unfortunately, a major obstacle for most of us average home builders would be cost. This "Dual Engine" package would probably not be cheap. However, this idea might be interesting to a manufacturer who wants to "rattle the cage" of the light twin market, which, eventually, may bring the cost down for the rest of us.
Let me know if you need my address to send the first prototype 
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04-17-2017, 07:57 AM
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Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 2,247
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Quote:
Originally Posted by Mel
A turbine engine in an RV-12 does not meet LSA parameters in the U.S.
This aircraft would be an amateur-built and could not be flown by a sport pilot.
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I'm not saying you're wrong... but where do you get that? I see a limit of a single engine... but haven't found a requirement that it be a piston engine. School me, please...
Not that I would do it, but it's interesting.
__________________
Dale
Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
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04-17-2017, 08:09 AM
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Join Date: Jul 2010
Location: Orlando, FL
Posts: 1,077
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Quote:
Originally Posted by DaleB
I'm not saying you're wrong... but where do you get that? I see a limit of a single engine... but haven't found a requirement that it be a piston engine. School me, please...
Not that I would do it, but it's interesting.
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Interestingly, here it says that in the US the engine type is not defined, just one engine, and either a FP or ground adjustable prop.
In Australia it says that it cannot be a turbine, but has no limitations on the type of prop....
https://en.wikipedia.org/wiki/Light-sport_aircraft
__________________
Chris Smith
Maule M5-180C (Sold)
RV-6 O-360 CS (Sold)
RV-4 O-360 FP (Sold)
Full-time in the other type of RV....
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04-17-2017, 08:23 AM
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Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,147
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Quote:
Originally Posted by ccsmith51
Interestingly, here it says that in the US the engine type is not defined, just one engine, and either a FP or ground adjustable prop.
In Australia it says that it cannot be a turbine, but has no limitations on the type of prop....
https://en.wikipedia.org/wiki/Light-sport_aircraft
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It's going to be difficult to run a turbine without an in-flight controllable prop. The turbine torque curve usually needs a pretty constant RPM, which does not match up well to a FP prop power demand.
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid 
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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04-17-2017, 08:29 AM
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Join Date: Mar 2005
Location: Dallas area
Posts: 10,769
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Quote:
Originally Posted by DaleB
I'm not saying you're wrong... but where do you get that? I see a limit of a single engine... but haven't found a requirement that it be a piston engine. School me, please...
Not that I would do it, but it's interesting.
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FAR part 1: "Light-Sport Aircraft (6) A single reciprocating engine, if powered."
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
Last edited by Mel : 04-17-2017 at 08:38 AM.
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04-17-2017, 08:37 AM
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Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 2,247
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Quote:
Originally Posted by Mel
FAR part 1: "Light-Sport Aircraft (6) A single reciprocating engine, if powered."
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Ah, there it is. Thanks!
__________________
Dale
Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
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