GA Turboprop

[kscessnadriver]

The turbine lag you talk about is true, especially with turbines and PT-6 style (the technology would be free power turbine) does have lag. The Honeywell TPE style is that of a direct drive essentially does not. It seems like the majority of these smaller turbines or anything that we are talking about in terms of size would be of the direct drive style, thus eliminating those issues.

I'd trade the lag of a PT-6 to not have the TPE that lets everyone within a 1 mile radius know there is an airplane running.

[uavmx]

I'd trade the lag of a PT-6 to not have the TPE that lets everyone within a 1 mile radius know there is an airplane running.

That's because pilots are too lazy to go to low speed. When they are running at 65%, it's not that bad. Bunch of pansies around here!! I love the smell and sound of turbine engines at 0600 :-)

[Bob Dingley]

I'm don't agree that free power turbines such as Lycs, RR, PW, Arriels and GE accelerate slower than single shaft turbines like the TPE (at one time; Garrets). Free power turbines were created instead to overcome lag. I would rate the response on par with some radials that I have flown. R-985, R-1300,R-1340. In all cases, smooth control means good airmanship no matter what you're flying. We do not operate our engines like a red neck in a pick up truck stomping the gas. Free power turbines spool up fast.
Bob

[steveinindy]

I'd trade the lag of a PT-6 to not have the TPE that lets everyone within a 1 mile radius know there is an airplane running.

Eh....we have the same problem with any engine in the hands of someone who doesn't know how to set it properly. We have plenty of PT-6 powered traffic here and even when they are on approach for 23L at KIND (roughly a mile away), you can still hear them if the pilot can't get it through his head how to configure it properly.

*perks up an ear* Speaking of that....

That's because pilots are too lazy to go to low speed.

What UAV said.

love the smell and sound of turbine engines at 0600 :-)

I don't like the smell of any engine but for some reason the smell of diesel is less offensive and vaguely comforting. I like to blame it on all that time I spent volunteering and working on and around diesel powered fire apparatus and ambulances.

would rate the response on par with some radials that I have flown. R-985, R-1300,R-1340.

Interesting. I've never flown anything with a radial so I can't make a comparison in that regard.

In all cases, smooth control means good airmanship no matter what you're flying.

Well said. However, I'm reminded of what my medical director as an EMS provider used to say about developing protocols, procedures and regulations: you keep in mind the guy you barely trust and wouldn't let have your life in his hands. In other words, you always design or write with the lowest common denominator in mind that way there's a sufficient margin of safety for those folks and an even broader one for the guy who is skilled at flying.

We do not operate our engines like a red neck in a pick up truck stomping the gas.

Those of us who know what they are doing. There are plenty of folks who do exactly that and it's one reason why engine shops stay so busy.

[Bob Dingley]

Free power turbines have little lag. Single shaft turbines do. I know for a fact that a PW or RR will spool up faster than my old fuel injected Beech. On the other side of the coin, I can chop power abruptly on a PW or RR with no problem. Try it in a Beech 50 with the old GSO-480s and you may see dimples appear in the cowls from the counterweights.
Bob

[Flyfalcons]

They didn't come up with the term "commander salute" (practiced regularly where I work) because some pilots are lazy.

[kscessnadriver]

Eh....we have the same problem with any engine in the hands of someone who doesn't know how to set it properly. We have plenty of PT-6 powered traffic here and even when they are on approach for 23L at KIND (roughly a mile away), you can still hear them if the pilot can't get it through his head how to configure it properly.

My comment was more about when they are on the ground. Work the ramp sometime. The difference between a C-90 and a MU-2 is amazing.

[steveinindy]

My comment was more about when they are on the ground. Work the ramp sometime. The difference between a C-90 and a MU-2 is amazing.

I fly on a MU-2B (with -10s) for one of my jobs. Both of them are pretty noisy. Honestly, once you get above a certain threshold, the actual noise level is pretty much moot at least in my book. Nearly every twin turboprop is really noisy in my book. I'm not saying there's an actual difference but it seems like once you get above 90 decibels it's a bit like arguing over the various shades of white paint.

Then again, I don't find the noise level from most aircraft all that pleasant which is a major reason why sound reduction is such a focus in my design.

[PF Flyer]

I will put in my 2 cents. No one mentioned Walter 601D turboprops. They are relatively inexpensive, simple, 750hp, and reliable. The fuel burn (from research, not ownership) is approximately 35% higher than a high performance piston. They can be found easily and TBO'd in Florida. There are no mid life hot inspections and IRAN is being increased to 2000 hrs. The calendar IRAN was murky to me. It is either 7 years or as needed for experimental aircraft. Look on Controller or Trade a Plane. You will see several installed....

[steveinindy]

I will put in my 2 cents. No one mentioned Walter 601D turboprops. They are relatively inexpensive, simple, 750hp, and reliable. The fuel burn (from research, not ownership) is approximately 35% higher than a high performance piston. They can be found easily and TBO'd in Florida. There are no mid life hot inspections and IRAN is being increased to 2000 hrs. The calendar IRAN was murky to me. It is either 7 years or as needed for experimental aircraft. Look on Controller or Trade a Plane. You will see several installed....

The only real "problem" with the Walter turboprops (now also available new as the GE H80) is that the "inexpensive" ones have to be viewed with a certain degree of caution and one must- as with any aircraft component- be sure to do their homework to make sure the engine is what you're expecting and to make sure the paperwork is in order so far as inspections, maintenance, etc. To be honest, I wouldn't accept an Soviet era engine without having it independently vetted by an A&P that I know and trust. Then again, that's the approach I take with anything I buy used from someone I don't know.

That said, the 601 series isn't really amenable to what the OP was talking about: a "replacement" for the average GA engine. The only thing disruptive about turbine technology tends to be noise and the bills for maintenance.