More On Flying Turboprops

[Tom Goodrick]

I recently did a flightin the Beech 350, one of my favorite aircraft. I was very bothered to find the power was very difficult to control. I had last worked on the 350 back in October 2007. That work is described in the section FS Piloting Procedures/Flying Turboprops in this Forum. (Unfortunately the data tables are all screwed up after the text was moved to this Forum.) I must have done something to mess up the FD files in the interim. I went back to that 10/07 version of the FD and the power became more manageable. I also found a cure for the taxi problem: reduce reverse thrust to -.35 and then you can make one tap toward reverse thrust on key F2 to get a steady taxi speed.

So it is now once again a nice aircraft to fly. (This set of FD is the one you can download from my site. (I think, check the date.) I got it from the folder I keep of uploads to my site.)

A new item not available at that time is my TPower gauge which should be installed and used by everyone flying a turboprop without the power-setting tables in the Pilot's Operating Handbook for the real aircraft. It simply presents an instantaneous power calculation using the percent torque and the percent RPM to show percent power. There are many combinations of RPM and throttle setting you can use that produce the same power. Passengers appreciate the reduced noise and vibration when RPM is reduced in cruise. The power-setting tables show a bewildering array of settings you can use in "carpet plots" depending on temperature and altitude. But the fact is that turboprop engines are sensitive to power level like all other engines so as long as you keep the individual parameters within reasonable limits and keep the displayed power level at a reasonable value, you will be flying the turboprop in a realistic way and performance will be realistic.

Here are some values I observed for the Beech 350 with a partial load of about 14,500 lbs at different altitudes, cruising at about 75% power:

Altitude ft___KIAS___KTAS___%Power___FFpph/e__OAT C
5000_______245___260_____75.44____461
10000______233___266_____75.40____453
15000______223___276_____75.84____449______-13.2
20000______219___293_____75.04____437______-22.8
25000______215___311_____74.58____429______-32.5
30000______204___323_____75.40____425______-42.1

The temperature is given as observed in "Clear Weather" for "Standard Conditions." If you fly in Real Weather and see a different temperature at these altitudes, you may get a different performance result for the same power level.

[Tom Goodrick]

My face is red. I don't stand quite as straight as I used to.

This note should be titled: "How NOT to Fly a Turboprop."

The way not to fly a turboprop is very simple to explain: Don't leave the gear down!

I did it and not on a short flight where I was not paying much attention. I did it on a flight that lasted nearly three hours. Much of that time I sat here wondering why the cruise airspeed at 26,000 ft was only 143 KIAS with the throttle at 84% and power at 77.25%. I looked for reasons:
1) There was a head wind. Airspoeed?
2) The temp was 10 degrees C warmer than Standard. (?)
3) Nothing on the panel seemed to indicate any problem. !!!?

Then after 166.86 minutes, my notes indicate I lowered the gear and set flaps to 20 degrees. I landed with the gear up.


I was flying the Beech 350 from Albuquerque to San Diego (KMYF) having started in the dark at 6 am. I paused before taxiing to install some interior lights so you could see a lit interior through the beckoning airstair door. (See below) I was making notations about all piloting actions to get the plane from ABQ to MYF. There is no notation that I raised the gear although that is a normally a reflex action that occurs as soon as I have positive climb rate and good airspeed. During the climb I expect to see low airspeed values compared to cruise but in this aircraft they are not as low as 127 to 147, especially when you reduce the AP vertical speed to 1000 fpm and set throttle at 100% (at 21,450 ft) to gain airspeed! I was disconcerted to see that my notainons about OAT made when pausing flight were wrong. You have to read OAT only when flying. When you pause the flight, OAT can decrease by 10 degrees C.

But I remember thinking after levelling off at 26,000 ft that something on the panel should be telling me something because something is definitely WRONG! I must have looked at those three big green lights several time without seeing them!

So it goes. At 166 minutes I tapped the G key and heard the gear operate. At about 169 minutes I landed gear up!

One problem with FS9 is that the G key works both ways. After takeoff you tap it to raise the gear. Before landing you tap it to lower the gear. Your action is the same in both cases. However, you do see the three green lights do different things if you are looking at them! On a real plane the lever for the gear has a little fake wheel on it to show that it is for the gear and you move it UP to make the wheels go UP and move it DOWN to make the wheels go DOWN. Do any yokes have levers like that for the gear? If so I will get one.

Here are the lines I added to the [lights] section of the aircraft.cfg file to put lights in the cabin. You cannot add any more lights or you lose the cockpit light.

light.8 = 4, -2.0, 0.00, 1.64, fx_vclighth,
light.9 = 4, -6.0, 0.00, 1.64, fx_vclighth,
light.10 = 4, -11.0, 0.00, 1.64, fx_vclighth,
light.11 = 4, -12.5, 0.00, 1.64, fx_vclighth,

On most one-day business trips in the half of the year between October and March, you start and end the trip in the dark. It is nice to walk toward a waiting aircraft on the ramp that is well lit.

[hanspetter]

As you have noted the gear operation is set to toggle in FS. There are no separate commands for gear up and gear down. Once you assign gear deployment to a key or a button it will toggle the gear.

However, there's another obvious option -- operate the gear by using the mouse to move the gear lever on the panel. By the same token, I never use key commands for radio and AP. I mouse click what I want to operate. I feel this brings me closer to simulating what we'd all be doing in a real cockpit.

Regarding joysticks and other controllers the sim decides whether a function is an axis or an on/off command. Levers can only be used for axes. While a real gear lever may be viewed as an axis it's really not since it won't provide the option of seamless intermediary choices.

[flaminghotsauce]

The Saitek panel has a real nice up/down lever to operate the landing gear:

www.flightsimdaily.com/wp-content/uploads/2008/12/frontt.jpg

[Tom Goodrick]

Hans, it would be easy to make a proper gear lever in hardware and hook it into FS9. You simply make a lever that trips a momentary switch at each end of its movement that sends a "G" command or an equivalent signal that can be assigned as a gear command.

Thanks, Flaming. Evidently Saitek has already done this. I'll look into it.

[Chris Ross]

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