25 Apr 2024, 08:11 [ UTC - 5; DST ]
|
Username Protected |
Message |
Username Protected
|
Post subject: Re: Turbine step up? Posted: 26 Jan 2019, 16:20 |
|
|
|
|
|
Joined: 01/30/09 Posts: 3355 Post Likes: +1963 Location: $ilicon Vall€y
Aircraft: Columbia 400
|
|
Username Protected wrote: As far as I know there are no complex cooling channels in any of the turbine blades on the common turboprop GA engines. Don't think the PT6 has any, not does the TPE331 or the RR250. They're just slabs of shaped metal. Also, all the common TP engines precede automated CNC machining, so at some point someone milled these entirely manually on a lathe/mill. Which makes it a little surprising they cost so much. This is exactly correct, which is part of the reason that smaller turbines cannot be as efficient as larger turbines. Without advanced cooling technology in the turbine blades, the gas temperatures have to be lower, which limits efficiency and limited efficiency reduces power output per mass of engine and increases fuel flow, and all in all, makes the small turbine cost more to run. Given all the complexities, I don't think we'll see inexpensive aero turbine engines anytime soon. It's just not a thing that lends itself well to personal-sized airplanes. With all honesty, in the under 350hp range and especially for intermittent use, a reciprocating engine fueled with gasoline makes more sense than anything else. I'd think certain changes would be reasonable and allow the use of ordinary unleaded gasoline with little penalty. Liquid cooling, electronic controls for ignition and fuel control, possibly reduction gear drive, all would likely contribute to making that happen. On the turbine side, it makes sense when the capital cost, operating costs and payloads balance out against the utilization. Flying is expensive, but flying is valuable. Every hour flown is a lot of money spent, but at least in a business environment, that's justified by the excess value created by the flight. High utilization means the ROI comes faster, because capital costs are time-based. The longer the capital is tied up, the more it costs. A $500,000 small turbine makes sense if it is generating value well in excess of its capital costs and the uptime and increased payload available produce more excess value. I have to admit, my airplane isn't earning a living or generating any excess value. It is there because I like it. I don't use it enough to justify it economically. Keeping the capital costs low are important for me. The only turbines I could consider are those as discussed in this thread. Realistically, on the tail-end of their capital/value curve, where running them until no longer airworthy and disposing of them is the plan. There's a spot on the depreciation curve where that happens, aka, "the disposable jet". Fly it to the boneyard. It works if there's a supply of engines and other parts readily available for the type. There are no cheap airplanes.
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 26 Jan 2019, 17:42 |
|
|
|
|
Joined: 12/03/14 Posts: 19252 Post Likes: +23622 Company: Ciholas, Inc Location: KEHR
Aircraft: C560V
|
|
Username Protected wrote: As far as I know there are no complex cooling channels in any of the turbine blades on the common turboprop GA engines. Don't think the PT6 has any, not does the TPE331 or the RR250. The TPE331-10 and later has cooling holes and passages in the first stage turbine wheel. Mike C.
_________________ Email mikec (at) ciholas.com
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 26 Jan 2019, 21:19 |
|
|
|
|
Joined: 05/05/09 Posts: 4966 Post Likes: +4797
Aircraft: G44, C501, C55, R66
|
|
Username Protected wrote: The thing I don't understand is why there are no experimental turbines? We've had them in the RC world for decades. Yes, they're inefficient, but obviously not hard to make as the prices of those clearly show. Scaled up and made to a slightly higher standard, they would provide some alternatives for the homebuilt crowd. Yes, not great fuel efficiency, but at least better reliability and access to cheaper fuel. That's funny! I have a bunch of model airplanes and if I had to make a bet that one would 100% start, I'd pick the $2,000 turbojet that burns a gallon of gas in 10 minutes but is 10000% reliable. I think you are definitely on to something.
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 11 Feb 2019, 14:36 |
|
|
|
|
Joined: 05/23/13 Posts: 6787 Post Likes: +7340 Company: Jet Acquisitions Location: Franklin, TN 615-739-9091 chip@jetacq.com
|
|
Username Protected wrote: I thought the Walther engines were experimental only? I thought other non-certified turbines have been used in EAB aircraft.
The Walter engines have been installed on both experimental aircraft, like the Lancair IV-P and on certified aircraft like the King Air C90, first with the Walter 601 and now with the GE H80
_________________ It’s a brave new world, one where most have forgotten the old ways.
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 11 Feb 2019, 16:53 |
|
|
|
|
Joined: 05/04/14 Posts: 119 Post Likes: +53
Aircraft: Lancair evolution
|
|
Username Protected wrote: The thing I don't understand is why there are no experimental turbines? We've had them in the RC world for decades. Yes, they're inefficient, but obviously not hard to make as the prices of those clearly show. Scaled up and made to a slightly higher standard, they would provide some alternatives for the homebuilt crowd. Yes, not great fuel efficiency, but at least better reliability and access to cheaper fuel. evolution lancair is experimental and has a PT-6 135 and there are about 80 flying around
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 08 Mar 2019, 18:15 |
|
|
|
|
|
Joined: 12/17/13 Posts: 6359 Post Likes: +5544 Location: Hollywood, Los Angeles, CA
Aircraft: Turbo Commander 680V
|
|
Username Protected wrote: Maybe I missed something, but I saw this a few weeks ago and meant to ask (got sidetracked and finally back to it ) https://www.trade-a-plane.com/search?ca ... e=aircraft@Adam S Frisch : "State Intentions" Yes, I put that on there before I decided to keep her.
_________________ Problem is the intelligent people are full of doubt, while the stupid ones are full of confidence.
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 08 Mar 2019, 18:26 |
|
|
|
|
Joined: 07/01/17 Posts: 64 Post Likes: +32 Location: Irvine, CA
Aircraft: DA-42-NG
|
|
"Roger". Username Protected wrote: Maybe I missed something, but I saw this a few weeks ago and meant to ask (got sidetracked and finally back to it ) https://www.trade-a-plane.com/search?ca ... e=aircraft@Adam S Frisch : "State Intentions" Yes, I put that on there before I decided to keep her.
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 09 Mar 2019, 21:17 |
|
|
|
|
|
Joined: 11/30/10 Posts: 4263 Post Likes: +3718 Company: Flagstaff-Williams Dev. LLC Location: KCMR
Aircraft: 1965 310J
|
|
Username Protected wrote: The thing I don't understand is why there are no experimental turbines? We've had them in the RC world for decades. Yes, they're inefficient, but obviously not hard to make as the prices of those clearly show. Scaled up and made to a slightly higher standard, they would provide some alternatives for the homebuilt crowd. Yes, not great fuel efficiency, but at least better reliability and access to cheaper fuel. Think for a bit about how many copies are going to be sold. Each market has to dilute the engineering/development costs by the number of units sold. Its why drones used to be expensive and now aren't. Same for aircraft engines. Add to that; what the market will bear for something that will/will not return a profit when used. RC turbines can be cranked out by the thousands and dont have to be certified and unless you hit someone in the head, the maker wont be sued for wrongful death. But the primary factor in cost is the abundance factor. (economy of scale in production).
_________________ All my friends are here. I know this because all my enemies are dead. :)
|
|
Top |
|
Username Protected
|
Post subject: Re: Turbine step up? Posted: 23 Apr 2019, 08:41 |
|
|
|
|
|
Joined: 11/06/10 Posts: 11898 Post Likes: +2854 Company: Looking Location: Outside Boston, or some hotel somewhere
Aircraft: None
|
|
Username Protected wrote: What's the update Adam? Any closer to being fully finished? Unless the plane is in the junkyard, airplanes and finished is an oxymoron. Tim
|
|
Top |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum
|
Terms of Service | Forum FAQ | Contact Us
BeechTalk, LLC is the quintessential Beechcraft Owners & Pilots Group providing a
forum for the discussion of technical, practical, and entertaining issues relating to all Beech aircraft. These include
the Bonanza (both V-tail and straight-tail models), Baron, Debonair, Duke, Twin Bonanza, King Air, Sierra, Skipper, Sport, Sundowner,
Musketeer, Travel Air, Starship, Queen Air, BeechJet, and Premier lines of airplanes, turboprops, and turbojets.
BeechTalk, LLC is not affiliated or endorsed by the Beechcraft Corporation, its subsidiaries, or affiliates.
Beechcraft™, King Air™, and Travel Air™ are the registered trademarks of the Beechcraft Corporation.
Copyright© BeechTalk, LLC 2007-2024
|
|
|
|