Ploxhoi said:
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
Ploxhoi said:
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.
Ploxhoi said:
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.
Ploxhoi said:
Give Innodyn some credit, thank you.
They need to
earn credibility by demonstrating proven numbers and transparent engineering....just like everyone else.
Ploxhoi said:
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.
Ploxhoi said:
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.
