Any Innodyn news?

[Barry]

Wow this is getting too technical. Poor Chad who had the misfortune to start this thread was only inquiring whether or not Innodyne were shipping their proposed turbine engine.

I am just a "little" pilot and am now baffled by all this technical information. What is a VMO and an MMO? I don't know if my RV6A has them and if so what do I do with them. Also I always thought that VD was some sort of disease it was best to avoid catching.

Poor old GMCPILOT seems to have got a real handbagging on all this. I hope it will not spoil his Christmas.

Barry

RV6A B&C Alternator, B&C Voltage Regulator, B&C Starter.

PS I try and avoid flying on the dark, windy and rainy nights!!

[N395V]

I am not a techno geek and do not play one on TV but...........

The attraction of a small turbine and it's attendent whine and smell is really strong. I have been watching the innodyn turbine for many years. It is a rebirth of another company tht went under. Contrary to rumor they did make good on the deposits from their customers.

Spent a lot of time talking to one of their techs and Greg Richter (Blue Mountain) who was one of their original investors/customers.

Two things I gleaned from them. In order to get their fuel flows down to reasonable levels ($) they are pulsing the fuel. Given the small size and tolerances the added heat from low fuel flow is giving them expansion problems with resultant contact of the turbine to the case (not good).

Also to generate the HP and Torque the turbine needs to spin at 60,000 RPM
and is geared down to 2700-3000RPM at the outpuut shaft. The noise level of a 2700 RPM prop in cruise has to be horrendous not to mention the bearing and gear stresses of 60'000 to 3000 RPM.

I think it will be many years before they are ready for daily use from the standpoint of TBO, economy, and noise.

[cjensen]

Originally Posted by N395V

Two things I gleaned from them. In order to get their fuel flows down to reasonable levels ($) they are pulsing the fuel. Given the small size and tolerances the added heat from low fuel flow is giving them expansion problems with resultant contact of the turbine to the case (not good).

didn't know that...good info...

Originally Posted by N395V

Also to generate the HP and Torque the turbine needs to spin at 60,000 RPM
and is geared down to 2700-3000RPM at the outpuut shaft. The noise level of a 2700 RPM prop in cruise has to be horrendous not to mention the bearing and gear stresses of 60'000 to 3000 RPM.

yeah, 2700 rpm in cruise is unfriendly to everyone. we turn the props on the king air at 1850-1900 rpm in cruise...that's comfortable!

Originally Posted by N395V

I think it will be many years before they are ready for daily use from the standpoint of TBO, economy, and noise.

no worries on the hijacked thread...it happens.

back on topic anyone??

[rv6ejguy]

On topic. Innodyne never responded to the two E-mails I sent last year and the previous year. People who never respond to my querries never will get my money.

Off topic

Any honest alternative engine advocate will readily admit that they spend lots of time on there engine, both in installation, operation and endless modification, but they will also tell you that this is the attraction of these engines, a tinker's play land. If you want to fly get a Lycoming. You want to experiment and tinker get an alternative.

George you might want to join the Eggenfellner Yahoo group. You will see dozens or hundreds of satisfied people flying his conversions with hundereds of hours on them with little or no maintenance performed during that time. While you might agrue that the Sube is more complicated, it has also proven to be as or more reliable than a Lycoming.

I agree that many one off auto conversions are a tinkerers dream but this has not been the case with Eggenfellners conversions.

[gmcjetpilot]

Originally Posted by fodrv7

George I do apologise for offending you in taking you to task on VNE. My intent is not to offend but rather ensure that information on this forum is accurate and provides information that will assist in the safe operation of our fellow Rvs flyers. If I didn?t live 8000nm away I would come over with a couple of beers for a Christmas drink. Have a great Christmas and a great New Years Eve too . Pete.

No apologies necessary, especially if you have facts and data to back them up. I appreciate your references and examples. I always enjoy learning. Going off memory gets you in trouble sometimes. I have not digested your whole post yet. As far as I know (knew) flutter is a function of true air speed not indicated. Therefore if using IAS as your limit or Never Exceed, you have to make adjustment for high altitude flight. Also knowing some Hi-perf gliders have a Vne correction cards I made some assumptions as to why, may be incorrectly. I'll get back to you if I have any questions. Cheers George
PS I think this discussion is great and is weeding out some misconceptions, including a few of my own. That is what a debate/discourses is all about.

Originally Posted by rv6ejguy

George you might want to join the Eggenfellner Yahoo group. You will see dozens or hundreds of satisfied people flying his conversions with hundereds of hours on them with little or no maintenance performed during that time. While you might agrue that the Sube is more complicated, it has also proven to be as or more reliable than a Lycoming.

I agree that many one off auto conversions are a tinkerers dream but this has not been the case with Eggenfellners conversions.

Again thanks, may be my opinion needs updating. I never addressed the Egg Subaru conversion, but must admit I did assume from early info and experiences of a few that it was a little more tinker intensive. As it matures it appears service history is proving the engine and installation, which takes time. Thanks for the update. However (you knew it was coming) my goal is good performance, light, simple, reliable and cost effective. The Subaru meets some of these critiera but not all (for me personally). Cost of the Egg FWF kit seems out of line (higher) to the cost of a new Lycoming. Weight is still an issue. As far as reliability I could not be any happier to hear folks are finding their Egg Subaru is reliable. In the end we are all out there, and we want everyone to be safe, never wanting anything bad to happen to a fellow aviator regardless of the engine. Thanks for the update, I will check it out. Merry Christmas George

[cobra]

George,
Just a quick comment on your "attack" . I enjoy your insights (dont always agree), but you do have a tendency to get off on a tangent from time to time. Regarding the Mazda, I never said, or implied, that the wankel was a turbine. My comment was simply an observation about the applicablity of turbines to our RVs. You misinterpreted my comment, then went on a multipage rage arguing with yourself. That said, I think your observations about Vne and reasonable power choice are extemely important.

FWIW, all internal combustion engines have a similar cycle that includes intake, compression, power, and exhaust (including the turbines). The biggest difference is that most use reciprocating action (w/ pistons) that create a lot of vibration and mechanical stress, and tend to be sensitive to high rpm operation. Because turbines and rotaries rotate continuously in the same direction, there are some similiar operational characteristics that include high-rpm operation with low vibration, simplicity, and favorable durability and power-to-weight advantages. I'll leave the value judgements to you and others.

I recently attended an EAA presentation by Williams International regarding their work with small turboshaft and jet engines. They pretty much agree that a small turbine is certainly possible, but not really economical for small GA planes like ours (they make engines for cruise missiles, Adamair, etc).

[Jconard]

The rotor does not simply spin as a turbine fan does. They follow and eliptical pattern, and an orbit involves the rotor accelerating against housing, an in terms of a vector, it stopps and goes in another direction. They place tremendous stress on the housings. Ever see one blow?

Unlike a spinning turbine. Rotary engines, when tuned to similar specific outputs, HAVE NOT been more reliable than similar piston engines in any application I am aware of, including road racing.

They have a differetn vibration, but certainly not less vibration.

[fodrv7]

VMO (Velocity Max Operating) is the equivalent of VNE.
MMO (Max Mach Operating) is maximum speed in relation to MACH 1.

So Barry that answers your question. But I can?t help myself.

VMO is usually around 330KT IAS for a Heavy Jet.
MMO is usually around Mach 0.85 for a Heavy Jet. ie 85% of the Speed of Sound.
The Speed of Sound = 661KT at ISA Sea Level and so Mach 0.85 (85%) is around 560KT
(The Speed of Sound is actually temperature dependant, but lets keep this simple.)

So if you are in an aircraft with a VMO of 330KT and an MMO equivalent to 560KT then the VMO is the limiting speed at Sea Level.

On the climb at around 30000' the TAS for VMO (330KT IAS) becomes higher than MMO and so MMO becomes the limiting speed.

The Barber pole George mentioned is a red striped speed limit at the top of the airspeed indicator and when MMO is limiting the Barber Pole slides down to obscure all IAS which will be higher than the MMO, which is now the limiting speed.

All of which is irrelevant to Rvs. But as my RV-7 has been at the paint shop for three weeks and they haven't yet picked up the sand paper, I am sitting here with no more rivets to drive or GRP to sand (thank God) and am easily distracted.

My apologies.

But I won't be able to avoid flying the aircraft I built much longer.

January?

Pete.

[Mike S]

The Mazda rotary engine uses rotors to do the same job as pistons in a "traditional" recip ingine. The rotors run on an eccentric shaft, which does the same job as crankshaft in our "traditional" engine-----it moves the rotor side to side in relation to the crand centerline, and up and down, and all points of the compass-------------and to add to that, the rotor has a gear that is meshed with a fixed gear in the side housing------------which causes the rotor to spin on the eccentric shaft as it is being displaced away from and then back toward the crank centerline.

What this all adds up to is wierd vibrations, and strange harmonics.This caused things to fatigue and brake, and then when you add the dics loads (vastly different than the loads imposed in an auto drivetrain) of a propeller, things get REALLY mixed up.

Dont get me wrong, I have owned and loved a rx-7, changed out the 12a for a 13b, and hot rodded that----------they make a lot of power, and run really smooth--------as percived by our butt in the seat----------but they do create vibration and harmonic problems that any self respecting turbine would self destruct at.

Good thread though----------------

Mike

[gmcjetpilot]

Wrapping it up

Bygones to all and glad we sorted this all out, great info everyone. I love a good beat down, it feels so good when it stops.

To make the debate about a single Vne limit vs. a Vne range (of lower IAS for higher altitude) relevant to RV's, be careful. I am left with the write up from the F-16/RV-4 pilot who dove too fast from altitude. http://www.vansaircraft.com/pdf/hp_limts.pdf (last page)


VNE and Safety
It gets to a point of regulation, aerodynamics and what is really going on specifically to our RV's. Yes I do think you should be aware of a the lower IAS vs. Vne at altitude. Regardless of how a factory (light) planes or transport jets are certified we need to be aware that the relation to flutter and TAS.

Reading your Australian regulations, and the equivalent US regs for normal, utility and transport aircraft that there is a process to make sure that Vne/Vmo/Mmo is not exceeded for all normal flight maneuvers throughout out the envelope. No need to get into it, but needless to say that whether a Jet has a moving barbber pole or Beachcraft has a single Vne (IAS) is not as important to understanding our RV's. They (RV's) are experimental and not really tested. So unless you run your RV up to 220mph IAS at a high altitude, you don't know what will happen. The conservative thing to do is fly at lower IAS at altitude so TAS does not exceed Vne. As we all agree that is not an issue in level flight with an ATMO piston engine, but watch the high dive.


Cobra thanks for the info, now get your turbine, I mean Rotary flying. When you get her flying post lots of pictures. Yes I get on a rant and rave, but I am back on my meds and feeling much better now.


I LIVE IN THE LAND DOWN UNDER
Thanks for the custom picture fodrv7, I thought you where smart, but seeing you standing out there on the wing (I assume its you) with out a net, makes me wounder. I checked my B757/767 manual for airspeed limits and it just says: "Observe IAS/Mach speed indicator limits" That is what is says and the only limit airspeeds are in non-normal procedures.

Boeing and most US airlines have got away from memorizing speeds, placards that are displayed and other useless data (stuff you can't do anything about or really matters to actual flying). It was OLD SCHOOL to be able to memorize the diameter of the fuel line. Some airlines still insist you regurgitate every number in the manual. Boeing's solution was to take the numbers out of the manuals, for better or worse. SO during an oral you don't need to regurgitate numbers (you know the ones you will forget later anyway). The implication to not having a single Vmo/Mmo to memorize is that your flight instrument or FMC displays them.


Cheers All George