lml@lancaironline.net Mailing List Archive

With this kind of engine in the pipeline,

http://www.aopa.org/oshkosh/2012/news/120723cessna-unveils-turbodiesel-182.html

240HP turbines sucking 28-32 gph are going to have a marketing problem.

Wolfgang

From: Sky2high@aol.com
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: New Turbine Engine
Date: Mon, 23 Jul 2012 08:31:08 -0400
To: lml@lancaironline.net

Mark,

Yes, but more importantly one should consider the designer's intended range of performance, stress, speed and loading. The turbine IV is an example of stretching the design parameters way too far (crappy wing anyway). For example, my airplane could have fun with an excess of 200 hp but the CG moves too far aft. OK, let's put the fuel forward - like in a tank forward of the current firewall? Arrrgghhh.

It would be great to see someone design a plane where that engine's power and weight were some of the parameters.

Scott

In a message dated 7/22/2012 12:00:37 P.M. Central Daylight Time, mwsletten@gmail.com writes:

I think Rob's point is that the Lancair (or other aircraft designed around recips) isn't the only kind of aircraft this engine might be used for. A particular installation might prioritize size/weight of powerplant over weight/cost of fuel.

--Mark

What's there to disagree with ?

At 10 gph more that's 180 lbs more in take off weight for a 3 hour flight.

A piston engine consumes about 0.5 lbs/hp/hr

That turbine is just over 0.8 lbs/hp/hr

For 200 HP output, that difference is 10 gph

. . . so 125lb turbine + extra fuel or 305lbs for a piston and less fuel cost . . . for the life of the engine.

. . . take your pick.

Wolfgang

----- Original Message -----

From: rwolf99@aol.com

To: lml@lancaironline.net

Sent: Friday, July 20, 2012 10:11 PM

Subject: Re: New Turbine Engine

I have to disagree with Wolfgang on this one, but I do accept his premise that a 240 HP turbine will consume a lot more fuel than a 240 HP recip.

But the amazing thing is getting 241 HP out of a 125 pound engine. *That* is impressive!

Put it in context - my IO-360 gets 180 HP and weighs 260 pounds. Marv's engine provides 33% more horsepower and weighs less than half. We can run every comparison under the sun and argue all day long to no conclusion -- how much extra fuel weight we need to carry, how much less engine weight we need, and so forth -- but the bottom line is that this little engine enables some aircraft designs that just would not be possible with a recip.

- Rob Wolf