Innodyn Turbine Engines

[mgomez]

Originally Posted by Ploxhoi

The fact is the efficiency of modern turboshaft engines.

( 255 shp * .42 lb/shp/hr ) / 6.7 lb/gal = 15.99 gal/hr

There are also many modern turbines with efficiencies around .45 lb/shp/hr.

( 255 shp * .42 lb/shp/hr ) / 6.7 lb/gal = 17.13 gal/hr

As your post indicates, that big Rolls-Royce engine has 14 stages of axial compression (pressure ratio 10:1 or so), compared to a one-stage centrifugal compressor for the Innodyn (3:1 or so). Compression ratio is a huge driver of efficiency...that's simple thermodynamics. The impressive SFC of that RR turbine is because of that simple fact, not any "modernity," if I may invent a word. There are very old turboprops that achieve impressive SFCs too...mostly by having many, many stages of compression.

The Innodyn is not really a modern turbine engine. It's a 40-year-old engine made with modern manufacturing methods and metallurgy, and controlled by a modern fuel controller. That will, admittedly, improve the SFC somewhat, but not by a factor of 2 or 3. The Solar T62, upon which the Innodyn is based, has an SFC of 1 to 1.3 lbs/hp-hr.

Please explain how modern manufacturing methods and an electronic ECU improve the SFC from 1 to 0.45 lbs/hp-hr.

[bumblebee]

Originally Posted by Ploxhoi

You guys have no right to be bashing Innodyn for their burn rate when you have absolutely nothing backing yourselves up.

Let's set the record straight, shall we? There is plenty of information.

Open the "hood" of a modern turbine and it is anything but simple. Yes there is "one moving part", but that's where "simple" ends.....and manufacturing that "one moving part" is among the most complex and expensive processes known to man.

Virtually any piston engine above a lawn mower is more efficient BSFC than a state-of-the-art turbine costing $20 million.

By Innodyne's own admission, their "engine" is based on a Solar T62 APU, a well known power-generator unit (never designed for flight OR continuous operation) from the 1960's with very "known" terrible BSFC rates in the 1.4 lb/hp/hr range

Originally Posted by Ploxhoi

The fact is the efficiency of modern turboshaft engines.
( 255 shp * .42 lb/shp/hr ) / 6.7 lb/gal = 15.99 gal/hr

There are also many modern turbines with efficiencies around .45 lb/shp/hr.

( 255 shp * .42 lb/shp/hr ) / 6.7 lb/gal = 17.13 gal/hr

The key word here is "modern". The Innodyne design is not modern by any standards. You are applying ".42" to Innodyne when you have no basis to make that calculation other than Innodyne's unsubstantiated (and unprovable) claims. The only turbines making .42 are enormous engines costing many $millions apiece and are far from "simple".

In lay terms, turbine efficiency (and power) is a direct funtion of the number and size of the compressor stages COMBINED with the FADEC control. As for Innodyne's "FADEC", this is vaporware UNTIL someone actually sees it and tests it INDEPENDENTLY. The "test" at Patuxtant was nothing of the kind.

Originally Posted by Ploxhoi

Problem with most turbine manufactures is they are making high power engines for commercial and military applications, not small aircraft.

Check the news for the past few years..... there's been a bit of activity in the VLJ segment and quite a few small turbofans from the likes of Pratt&Whitney, Williams and Honda-GE who spend millions developing these engines. While these engines are never sold "retail", you can safely assume at least $400k apiece.

Originally Posted by Ploxhoi

Give Innodyn some credit, thank you.

They need to earn credibility by demonstrating proven numbers and transparent engineering....just like everyone else.

Originally Posted by Ploxhoi

BTW you all should know testing and documentation for the FAA takes forever.

Not true. A clean-sheet engine takes 3-4 years, assuming the engine design is "ready to go" at the outset of the certification process. I've done several "clean-sheets", both piston and turbine. Contrary to popular myths, FAA is very cooperative and just as interested in seeing new engines get to market as the rest of us (no I don't work for FAA).

Let's suppose for a moment that Innodyne was thinking "Certification":
Because the Solar design is known to the FAA, certification of Innodyne's modified version would take no more than 24 months BUT the Solar was never designed for primary flight....which puts it into PMA category.

Testing and certifying an engine by itself is quite simple.
The biggest hurdle in any "major" or "primary to flight" FAA certification (engine, airframe or propeller) is PMA certification, i.e. the manufacturing process MUST be certified as well. This requires very elaborate tracking of components and processes all the way back to the raw materials. And every supplier must also be PMA certified. This is a highly rigorous and expensive requirement, which is why "any old supplier" is out of the question for certificated engines. Thus PMA consumes most of the 3-4 years.

To obtain a PMA, Innodyne would either need to develop a full production process in-house OR utilize PMA-approved suppliers all the way back to the foundry. In the turbine sector, the manufacturing of compressor disks requires IMMENSELY EXPENSIVE equipment and precision metallurgy. As for outsourcing, there are zero (0) PMA'd suppliers willing to manufacture compressor disks for "3rd party" designs such as Innodyne.

Originally Posted by Ploxhoi

I am sure they are doing what they can to push this turbine through the FAA and get certification.

Innodyne has no (stated) plans to obtain FAA certification. See "PMA".

Certification isn't required for Experimental....but it DOES provide a major level of confidence to the 99.9% of "experimental" builders who are really not interested in being true test pilots.

Which is why any engine manufacturer that is serious about selling more than 15 engines will get FAA certification for PMA and for propulsion combinations (propellers, fuel systems, FADEC, etc.).

The final hurdle is obtaining airframe combinations....which entails very extensive (expensive) engineering, vibration-, stress- and flutter analysis.

Even at the experimental level, these efforts are virtually mandatory for any major airframe designer (Van's....) to "bless" a new engine. And that would be AFTER a long series of successful, trouble-free flights.

As for "design approval", any experimental airframe manufacturer with a brain (i.e. Van) would NEVER formally "design around an engine" until the engine is proven first. And the only way to prove it -- for aviation purposes -- is to certify it.

For those of you keeping score at home, Thielert/Superior and Rotax are the only engine mfrs. that stand a chance of making it into Van's catelog anytime soon.

[Ploxhoi]

Efficient turboshaft engines do not have to be massive.

LHTEC T800-LHT-801 Turboshaft Engine

* Type: Dual spool, free shaft turboshaft
* Inlet: Axial with integral active particle separator system
* Compressor: Two stage centrifugal
* Burner: Annular, reverse flow
* Turbine: Dual spool, two stage axial gas producer turbine, two stage power turbine
* Exhaust: Rearward axial flow, single exit exhaust outlet
* Power Rating: 1,563 shaft horsepower at 23,000 rpm (takeoff rating)
* Rated Torque Output: 356 lb/ft @ 23,000 rpm
* Peak Torque: 676 lb/ft
* Weight: 315 lbs.
* Power/weight: 4.9:1
* Compression Ratio: 14.6:1
* Air Mass Flow: 10.0 lbs/sec @ 44,850 rpm
* Specific Fuel Consumption: .45 lb/shp/hr

That turbine isn't massive, and there are plenty of others with similar efficiencies in this size or slightly larger.

Just too much power for many light aircraft.

Being based on the Solar T62 APU does not mean its a clone and modified T62 are a lot more efficient than 1.4 lb/hp/hr. (1.2 - 0.85 lb/hp/hr)

Also the T62 is qualified for use in aircraft, helicopters, vessels and ground power units.

Why can't Innodyn's turbine have a 0.47 lb/shp/hr rating?

Why isn't Innodyn's engine design modern, even if they have based it on the T62?

BTW here is a quote from Innodyn's website.

Innodyn is currently working with regulatory experts to conduct a feasibility study to determine precisely which tests will need to be completed to provide appropriate certification data to the Federal Aviation Administration, and expects to have more information on this process and company plans in January 2005.

Looks like they are considering certification, of course their turbine is still experimental at this time.

Yes their site needs a lot of updating.

[gmcjetpilot]

Originally Posted by Ploxhoi

Give Innodyn some credit, thank you.

When Credit is due?

When it comes to taking money from fellow pilot/builders who will put their lives and lives of their passengers on the line behind this power plant, I think criticism and review is in order.

No one needs to sugar coat or blow smoke up the companies flag poll, when that flag poll has some red flags waving around all ready.

Feel free to ignore all advice and comments and be an Innodyn cheer leader, but common sense would say be careful. There are some members of this list who work in the turbine engine field who have made great points.

Sure we would all hope its everything every kerosene dreamer could hope for, but aviation is not for dreamers. There is hard facts and the ground is very hard when it Cometh up and Smite Ye Mightily. I just don't want builders to get ripped off or worse, hurt.

[rvpilot]

You guys have no right to be bashing Innodyn for their burn rate when you have absolutely nothing backing yourselves up

Let's see, sitting in the cockpit, with the turbine running at the low power setting, looking at the Shadin fuel flow indicating slightly less than 20 GPM. I'd say this merits saying their fuel flow's not what it's cracked up to be!
There are legitimate numbers out there to back up greater fuel flow numbers than they are claiming! The -4 is not the only RV that was ever flying, even though it's flights were limited.
As has been previously stated, be very cautious of what you're told by these folks.
And, while we're at it, what happened to the fellow who has one of these in his -8?

[nucleus]

The Solar T-62 Turbine was originally designed for a helicopter.

I see Rolls Royce has a new smaller turbine out:

Rolls-Royce RR300 to power new Robinson helicopter
02 March 2007
Orlando, FL: Rolls-Royce, a world-leading provider of power systems and services, will supply a new turboshaft engine to power Robinson Helicopter Company?s new R66 rotorcraft, it was announced today at Heli Expo.

The new RR300 engine represents a major step forward in the helicopter industry by providing 300 shaft horsepower at takeoff, excellent hot and high performance and outstanding value. The RR300 makes Rolls-Royce turbine power available in the lower shp range.

The new R66 model, a five-seater, is Robinson Helicopter Company?s first venture into gas turbine-powered rotorcraft and will complement the company?s existing line of piston-powered aircraft.

Rolls-Royce expects FAA type certification by 2008 with full-rate production to follow. Under the agreement with Robinson Helicopter, Rolls-Royce will provide several hundred RR300 engines in upcoming years.

Rolls-Royce is the world-leading producer of light turbine engines in the helicopter market. The Model 250 line has produced nearly 30,000 engines, with approximately 16,000 currently in service worldwide in a wide range of aircraft styles.

The RR300 embodies new technology and advanced design methodology. The engine draws on the proven record of other Rolls-Royce turbine powerplants to deliver a powerful, dependable engine at a competitive price.

Key attributes of the RR300 include: lower acquisition and operating costs; low-weight, compact design; improved specific fuel consumption; an embedded engine monitoring system; and an optional, through-life, peace-of-mind maintenance program.

The new aircraft deal brings together two industry-leading rotorcraft companies.

Scott Crislip, President Helicopters & Small Gas Turbine Engines for Rolls-Royce, said, ?We are honored to join with Robinson Helicopter Company on its first turbine-powered aircraft, the R66. We anticipate a great future partnership on this industry-changing aircraft. The RR300 engine represents the latest technology in turbine power and once again Rolls-Royce is leading the way. You will see big things from this small engine.?

Robinson Helicopter Company is the world's leading producer of civil helicopters and is known for its high performance, reliable aircraft.

Founded by Frank Robinson, the company sold 806 rotorcraft in 2005, the most civil helicopter sales of any company in the previous 25 years. The company has produced more than 7,000 helicopters overall.

[John Clark]

The only production helicopter that I can find that used the Solar T-62 was the Boeing-Vertol CH-47 "Chinook" as an APU running a hydraulic pump and a generator.

This discussion seems to have a life of it's own, here is an article from Sport Aviation 5 years ago:

http://www.eaa.org/benefits/sportaviation/RV-4T304.pdf

This was about "Affordable Turbine Engines" which morphed into Innodyne which, it appears, has morphed into obscurity.

John Clark
RV8 N18U
KSBA

[nucleus]

Originally Posted by John Clark

The only production helicopter that I can find that used the Solar T-62 was the Boeing-Vertol CH-47 "Chinook" as an APU running a hydraulic pump and a generator.

The T-62 was designed for a one man hlicopter that was never constructed. It was neverused for anything bu an apu unless you count the jet-exec and helicycles.

Nucleus

[captainron]

Probably the biggest thing to remember is that fuel flow in a turbine is directly related to altitude, or more precisely density altitude. As an example, in the Turbo Commander, at altitude each engine is developing 600 hp. and using 260 pph.. If you could use an engine of this type in an RV, and scale it to our needs, you could interpolate say a quarter of this hp and fuel flow. You would be looking at 150 hp. with 65pph, or 9.7 gph. No one could complain about this except that you would have to be flying at FL 250-FL270 to achieve this! Unlikely in a Vans. Come down to the altitudes where we have to fly and you'll be installing drop-tanks. Sure, APU's are fuel hogs, but their normal operating conditions are running flat-out on the ramp!
One of the hardest things to scale down when you're building smaller engines is controlling the clearances. If you think about the compressor section of a jet engine in an airliner, you can imagine the spinning compressor blades with their tips being just a few thousandths of an inch from the housing. There are some compression losses here from these clearances, but the area of the compressor is great compared to the clearance loss. When you scale the engine down and try to use a much smaller diameter compressor, the ratios of loss from the required clearances increase greatly. What can be done to make up these losses? Build to much tighter tolerances? Expensive. Run the engine faster? More fuel required to do this, and possibly more exotic engine components=Expensive.
How much will you pay for a turbine engine for an RV when you know you can't operate it at an optimal altitude anyway? I really like the idea of a direct drive, two-stroke turbo-diesel when they become available, are proven reliable, don't add to the weight including their cooling system over what a Lycoming weighs, and when the whole package is consistent in price with a Lycoming/Lyclone. Rant over.

[mgomez]

Originally Posted by Ploxhoi

Efficient turboshaft engines do not have to be massive.
Being based on the Solar T62 APU does not mean its a clone and modified T62 are a lot more efficient than 1.4 lb/hp/hr. (1.2 - 0.85 lb/hp/hr)

Can I please have a link or a reference to a modification that makes the T62 more efficient? Thanks.

Originally Posted by Ploxhoi

Why can't Innodyn's turbine have a 0.47 lb/shp/hr rating?

Because its pressure ratio is much too low. What have they changed that affects the thermodynamics?

Be realistic: if Rolls-Royce, GE, P&W and Honeywell could make engines with good SFCs with only one stage of compression, don't you think they would? Do you think that engine you quoted has 14 stages because they AREN'T necessary?