Turboprops...

[dickbloom 0]

I think there is some confusion here between the RW engine and the modeling in MSFS. The MSFS modeling is not correct. I would suggest in FS you set the condition levers (King Airs or other PT6A engines) to just above the "cutoff" point and then use the power levers to handle the a/c. On the ground and takeoff the prop levers will be full forward, but reduced a little for climb and reduced a little more again for cruise. I can't give you the figures to use for reduction because I don't use that a/c in FS very often.db.

[dickbloom 0]

Do any of you know if FS models the increase in thrust when increasing the prop pitch a bit? I'm really wondering about that, considering it doesn't slow you down at all realistically when you put the props into full low pitch.

ummm...guess I don't understand the question. PT6A: first, whenever I wanted to slow the a/c first thing was to reduce power (power levers). At a given power setting, if you reduce prop rpm the torque increases, if you add prop rpm the torque decreases. I never noticed this in FS.db.

[Guest jonthedoors]

Don't even get me started on the TBM700 that's here on avsim!That's so hard to taxi, it's as if you move the throttle 1% forward and you're rocketing ahead at 30KTS!

[Guest jonthedoors]

Wait, I mean power lever.I forgot which thread I was in; I'd better correct myself before you guys crack down on my case!

[protzler 0]

ummm...guess I don't understand the question. PT6A: first, whenever I wanted to slow the a/c first thing was to reduce power (power levers). At a given power setting, if you reduce prop rpm the torque increases, if you add prop rpm the torque decreases. I never noticed this in FS.db.

You answered it! Sorry, when I typed it I was tired.Thanks!

[ronzie 21]

I think we are saying the same thing:Low or "ground" idle for taxiing. High or "flight" idle for all airborne phases. I think that's what I stated but perhaps confusingly and apologize. I used the words "power" lever meaning throttle or thrust control and "condition" lever for idle setting. I was not aware the PT6 flattened the props at throttle idle. I have a R/W article that stated some Saab 340B pilots on approach before the inner marker used a flat pitch with throttle at idle to use the prop as an air brake (they referred to it as "flat blading"). Their idea was to initiate final coming in "hot" and then quickly slow the aircraft with the flat prop to expedite traffic and reduce time and fuel on final. Once the airspeed was correct the thrust lever was advanced again to maintain landing airspeed and descent rate with the prop back at full (rpm) landing prop pitch. I think I was reading about REX Australia operations but I'm not sure. I thought they achieved flat pitch by adjusting the prop lever to low rpm and throttle near idle. It probably varies somewhat by aircraft.I also have a R/W book, "The Turbine Pilot's Flight Manual", 2nd Edition (out of print now but a great book) that was written for piston engine pilots to upgrade to both turbo-prop and pure jet aircraft that explains the operation of the condition lever which is defined as the idle state and in some cases fuel cut-off. My real world experience is only piloting piston engine SE including constant speed props. What is confusing for me is that times times the prop rpm lever is referred to as the condition lever.On the PC I have never needed to place the condition lever in low idle either in any stage of flight. I mostly use Mike Stone's aircraft with a customized panel for the 340B. I also note that on the PC the torque reading varies(at constant throttle) with prop rpm. Back to the OP's question:In some aircraft (including jets) taxiing is sometimes done on one engine to stay slow where ground idle and throttle idle result in too fast a taxi once the aircraft overcomes inertia and starts moving. They claim that at slow taxi speeds assymetric thrust is not a problem. (There is another technique also incorporated in some jets, can't be used in turbo-props, where instead of braking they they move the throttle or reverse thrust levers just enough to open the reverse thrust buckets keeping the engines idled - called reverse idle - to slow the aircraft if it gains too much speed. This avoids brake wear.) I don't know how well FS models this.As another reply stated I sometimes cheat on the PC by reducing the prop lever to a lower rpm position to reduce prop thrust for taxiing.

We are talking about PT6A engines- any other turbo-prop I have no idea. Possibly engines with "flight idle" are different from "high idle"? I have no idea. In flying the PT6A engine I never saw a pilot, nor myself taxi with high idle. Neither when flying, nor training or PC checks, was spool up time an issue. In line with that, in normal ops, I never had the engines at idle while in the air (training or PC's excepted)- reduced power on approach yes, but not at idle. When the power levers are pulled back to idle the props go flat and you fall like a brick. It's a little difficult to run explanations here at this point because I don't know your RW experience in general, or with turbo-props or the PT6A. Did or do you actually fly these engines?db.

[Guest belga1]

Hello,

This avoids brake wear.)

On the big airliners brake wear is indeed a problem .. but the biggest problem (and this to avoid for safety matter) is the overheating of the brakes ! who is far more dangerous (at short term) than wear.Regards.Gus.

[dickbloom 0]

I don't think theSAAB uses the PT6A engine- could be wrong tho.Not to beat a dead horse, but terminolgy for te PT6: Condition Lever- B99, B1900, King Air- cutoff, low idle, high idle. DHC6 (twin otter)- off, on. Prop Levers- control prop rpm except in beta range- low power setting whiick is set by power levers. Power Levers- set engine power and in beta range contol prop rpm. "flight /ground idle" is not a term used with the PT6's.Wrong nomenclature can cause confusion.db.