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  #71  
Old 03-01-2019, 12:00 PM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
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Quote:
Originally Posted by Turbine Aeronautics View Post
There will not be a significant difference in fuel flows between our 200hp engine at 150hp/10,000' compared to the equivalent 200hp piston engines at 150hp/10,000'. In fact, they should be very similar.
If you succeed in achieving .5 pph/hp, and measure in gph instead of pph, correct - the difference in fuel density should just about compensate for the difference in BSHP.

Quote:
However, our 200hp engine is being optimised for a 180hp cruise at 10,000' which is a power the piston engines generally will not achieve (unless augmented).
That almost makes my teeth hurt it is so painful - building a rocket and assuming it will only fly up to 10,000? Like a turbonormalized piston, this engine will shine most up higher.

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...

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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  #72  
Old 03-01-2019, 12:25 PM
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rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
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Quote:
Originally Posted by breister View Post
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').
I don't think you'll see a non-flat rated 200hp turbine produce 150 hp at 17,500 feet. Turbo normalize the Lycs and you'd get some good speeds and fuel flows running LOP.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #73  
Old 03-01-2019, 03:09 PM
rocketman1988 rocketman1988 is offline
 
Join Date: Jun 2010
Location: Sunman, IN
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Default 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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Bob
Aerospace Engineer '88

RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
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Dues+ Paid 2019,...Thanks DR+
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  #74  
Old 03-01-2019, 03:49 PM
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airguy airguy is offline
 
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Quote:
Originally Posted by rocketman1988 View Post
"... 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"...
Sure, but none of the rest of it matters without that "small bleed air port". Gotta have one before you can worry about the other.
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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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  #75  
Old 03-01-2019, 04:10 PM
rocketman1988 rocketman1988 is offline
 
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Location: Sunman, IN
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Default 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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Bob
Aerospace Engineer '88

RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...

Dues+ Paid 2019,...Thanks DR+
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  #76  
Old 03-01-2019, 04:32 PM
rdrcrmatt rdrcrmatt is offline
 
Join Date: Oct 2014
Location: Milwaukee, WI
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Quote:
Originally Posted by rocketman1988 View Post
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...
nuh-uh! Have you seen how easily that Raptor guy is doing it?
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  #77  
Old 03-01-2019, 06:19 PM
rocketman1988 rocketman1988 is offline
 
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Location: Sunman, IN
Posts: 2,189
Default 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...
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Bob
Aerospace Engineer '88

RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...

Dues+ Paid 2019,...Thanks DR+
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  #78  
Old 03-02-2019, 10:00 AM
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airguy airguy is offline
 
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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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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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  #79  
Old 03-02-2019, 10:34 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
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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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  #80  
Old 03-03-2019, 03:50 AM
Turbine Aeronautics Turbine Aeronautics is offline
 
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Location: Adelaide, South Australia
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Quote:
Originally Posted by rv6ejguy View Post
I don't think you'll see a non-flat rated 200hp turbine produce 150 hp at 17,500 feet. Turbo normalize the Lycs and you'd get some good speeds and fuel flows running LOP.
For your interest, our current predictions (subject to validation once the engine is running of course) at 20,000? give a maximum continuous cruise power of 138hp with a fuel flow of around 9.8 usg per hour at a 180ktas cruise state, ISA conditions.

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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