GeeBee Slow creeping

[gray eagle]

With engine running, When I apply the parking brake in the cockpit the aircraft stops but when I have the throttle all the way back and release the parking brake, the plane
will roll forward and as long as I apply the brakes it will stop but release them, it will roll and if not stopped will accumulate taxi speed. Is this normal?

I don't recall in other fixed wing aircraft where it would taxi with brakes released and no throttle applied.

If I use F1 key and apply brakes, it will stop and remain so until I apply a little throttle, apply brakes only and after coming to a complete stop it will roll out till I rinse and repeat with the F1 key and hit the brakes.

I've noticed that the manifold pressure gauge will indicate 11 or 12 if I stop the aircraft and when I use the F1 key the manifold gauge will zero out (or below) and aircraft will not roll forward.

[Mach3DS]

Sounds like your throttle axis needs to be calibrated or increase the low end dead zone a bit so that it actually goes to zero input when at idle position.

[Willy]

If you're talking about the Alabeo Gee Bee, it does me the same way. I've just figured that it has enough power to pull it along at idle. Very light aircraft with a lot of engine.

[gray eagle]

I am speaking of the Alabeo GeeBee. Would you please elaborate a little more on the throttle axis, are you speaking about the joystick settings?
If so, I did calibrate my Logitech xtreme pro and the slider window graphic displays the throttle backwards, i.e., full forward the graphic move to the left,
throttle closed, the graphic is filled with color suggesting a backwards function. In FSX, the joy throttle full forward advances throttle and pull the joy throttle back the engine
in fsx will idle.



Sounds like your throttle axis needs to be calibrated or increase the low end dead zone a bit so that it actually goes to zero input when at idle position.

[Mach3DS]

In fsx when you go to options>controlsThere should be a button to select axis. It will show your joystick and should show you a bunch of sliders that can increase or decrease your sensitivity or dead zones. Select your throttle axis and adjust. If your calibration is set then perhaps theRe so much power in this plane that even small amounts of throttle movement are generating power enough to move. Increasing the dead zone would negate perceived non inputted throttle movements.
I am speaking of the Alabeo GeeBee. Would you please elaborate a little more on the throttle axis, are you speaking about the joystick settings?If so, I did calibrate my Logitech xtreme pro and the slider window graphic displays the throttle backwards, i.e., full forward the graphic move to the left, throttle closed, the graphic is filled with color suggesting a backwards function. In FSX, the joy throttle full forward advances throttle and pull the joy throttle back the enginein fsx will idle.

[Dev One]

Sounds as if the FDE needs a bit of work on the prop values!
Keith

[Mach3DS]

I have the Alabeo GeeBee, it does not behave this way for me. So it's likely your joystick settings interacting with this AP power combination.

[gray eagle]

I Understand what you are saying however, I do not experience this issue with other flight sim aircraft just this one... when at idle, brakes on and hit F1 key, I notice that the manifold pressure
and RPM gauges read at a lower setting and when I release the brake it will not creep forward. Just have to remember that when I fly this plane, to try to reduce the idle speed a bit more.


I have the Alabeo GeeBee, it does not behave this way for me. So it's likely your joystick settings interacting with this AP power combination.

[Willy]

When it starts creeping with me, I tap the brakes a couple of times and it decides to play nice at that point. Until I hit the throttle, then the show is on.

[gray eagle]

I submitted a trouble ticket to Alabeo and hopefully they will come back with something positive. IMHO, I think there must be something in the code that could be fixed. Just a guess.
When and if I hear from them, I will let you know.



When it starts creeping with me, I tap the brakes a couple of times and it decides to play nice at that point. Until I hit the throttle, then the show is on.

[Bomber_12th]

I've never thought of this as being unrealistic, as the same thing will happen in various aircraft in reality as well - I believe, for instance, the B-25 will start creeping forward on a tarmac surface, even at idle power, if the brakes aren't held.

[Willy]

I've never thought of this as being unrealistic, as the same thing will happen in various aircraft in reality as well - I believe, for instance, the B-25 will start creeping forward on a tarmac surface, even at idle power, if the brakes aren't held.

That's what I have been thinking all along as well.

[SSI01]

I get this now and then in aircraft from all manner of makers - freeware and payware. They will creep on the tarmac at idle no matter what you do, regular brakes or parking brakes, and when you release either brake - some of them bolt forward out of the chocks, and some accelerate so rapidly they are at 60-70KIAS within a few plane lengths.

I've noticed turboprops seem to be the biggest offenders, and no matter what combination of engine/prop you use, or how you juggle fuel flow, they still do this. One of the biggest offenders was the KBT P-3 Orion, no matter what I tried using the controls in the cockpit that thing was seriously nose-bobbing all the way down the taxiway because of constant brake application and release - highly unrealistic, and a real off-putter. I've seen these things with my own eyes for years, when I was at the NASJRB in New Orleans. They taxied from walking speed up to maybe 10 or so MPH. We as sim pilots should be able to do the same. I mean, is it that tough to get this behavior into the flight model before it's released?

[Motormouse]

I've noticed turboprops seem to be the biggest offenders, and no matter what combination of engine/prop you use, or how you juggle fuel flow, they still do this. One of the biggest offenders was the KBT P-3 Orion, no matter what I tried using the controls in the cockpit that thing was seriously nose-bobbing all the way down the taxiway because of constant brake application and release - highly unrealistic, and a real off-putter. I've seen these things with my own eyes for years, when I was at the NASJRB in New Orleans. They taxied from walking speed up to maybe 10 or so MPH. We as sim pilots should be able to do the same. I mean, is it that tough to get this behavior into the flight model before it's released?

Trouble with turboprop is the ms datum model is PW PT6 a la King Air, now , when taxiing a turboprop you are in what is known as beta range, (http://www.skybrary.aero/index.php/Beta_Range) where moving the throttle also gives you direct control of prop pitch.

This is achieved by clever mechanical linkages , which effectively disable the propellor governor by resetting the speeder spring to a range where it will not interfere (except in prop ultimate overspeed only, ie the never exceed limit), while at the same time allowing throttle lever control of prop pitch.

Trouble is ms couldnt program this. They made a hash of the PT6 by not understanding its workings, then passed that off as an acceptable turboprop flight model.

The method I was taught to taxi turboprops (rw btw if you hadnt guessed) is to pitch props until aeroplane starts to move then come back to the ground fine, with four engines you can balance the outer pair in ground fine or min reverse even, and just taxi on inner pair.

Ttfn

Pete

[Willy]

450hp, under 2300lb max gross and designed for low drag (circa 1931). Unlike the original Z, the Alabeo one has a constant speed prop.

[gray eagle]

Thanks for the info.


I've never thought of this as being unrealistic, as the same thing will happen in various aircraft in reality as well - I believe, for instance, the B-25 will start creeping forward on a tarmac surface, even at idle power, if the brakes aren't held.

[heywooood]

Thanks for the info.

To check and see if your throttle on the joystick needs re calibrating, first - reduce the throttle using the joystick lever - then grab the VC throttle lever with the mouse and drag it all the way to the closed position.
if you can move the throttle toward the closed position AFTER you have already used the joystick then you need to recalibrate it.

In my case - the throttle on the joystick functions properly but only after cycling it fore and aft a couple of times. Just as on a real aircraft - the pilot will generally work all of the levers prior to engine start.
the mixture and prop levers (if present) are deflected fully a couple of times to ensure smooth operation. So too the throttle. If I do this prior to engine start (or afterward with the parking brake set) my joystick throttle functions properly and gives me full movement of the vc levers.

[gray eagle]

That creep issue seems to of went away. I loaded a previous flight of the GEEBEE and the engine was already running (at idle) and the JS throttle was fully closed, I opened both the VC and JS throttle
and the engine advanced same way - applied/released JS brake - plane remained at full stop. I had previously cal'd the JS before your input. So for now, I guess it's sorted.






To check and see if your throttle on the joystick needs re calibrating, first - reduce the throttle using the joystick lever - then grab the VC throttle lever with the mouse and drag it all the way to the closed position.
if you can move the throttle toward the closed position AFTER you have already used the joystick then you need to recalibrate it.

In my case - the throttle on the joystick functions properly but only after cycling it fore and aft a couple of times. Just as on a real aircraft - the pilot will generally work all of the levers prior to engine start.
the mixture and prop levers (if present) are deflected fully a couple of times to ensure smooth operation. So too the throttle. If I do this prior to engine start (or afterward with the parking brake set) my joystick throttle functions properly and gives me full movement of the vc levers.

[SSI01]

Trouble with turboprop is the ms datum model is PW PT6 a la King Air, now , when taxiing a turboprop you are in what is known as beta range, (http://www.skybrary.aero/index.php/Beta_Range) where moving the throttle also gives you direct control of prop pitch.

This is achieved by clever mechanical linkages , which effectively disable the propellor governor by resetting the speeder spring to a range where it will not interfere (except in prop ultimate overspeed only, ie the never exceed limit), while at the same time allowing throttle lever control of prop pitch.

Trouble is ms couldnt program this. They made a hash of the PT6 by not understanding its workings, then passed that off as an acceptable turboprop flight model.

The method I was taught to taxi turboprops (rw btw if you hadnt guessed) is to pitch props until aeroplane starts to move then come back to the ground fine, with four engines you can balance the outer pair in ground fine or min reverse even, and just taxi on inner pair.

Ttfn

Pete

Hey Pete, thanks for the info. I had another try at taxiing the CS C130Xperience this afternoon. After engine start and warm-up, I left the throttles at ground idle, ran the prop pitch all the way up to just below "air start," and still had that "zoom out of the chocks" problem. Also tried running those pitch levers down some, to just above "stop" setting, and that did slow the turkey somewhat but it was still headstrong. For some reason, after braking and stopping the beast I went to my mixture "lean by increment" setting (ctrl-shift-F2), tapped it a few times, and the aircraft immediately slowed its taxi speed. Throttles didn't move, neither did prop levers. Figured I was on to something (like maybe this approximated the fuel condition levers in the KingAir), so I kept props at ground idle, didn't change the fuel condition lever setting I got with the "lean mixture incrementally" trick, and didn't use joystick throttle but instead used "F2" and "F3" on the keyboard to run the engines up and down VERY slightly, and actually got the thing to approximate walking speed. You've got to advance/retard the throttles a very little now and then using those keys, but I think I've got this thing under control somehow. You're never going to reach and maintain a steady ground speed, but as you said, I suppose that's RW anyway.

[napamule]

Don't ask 'WHY?' but when you first load your ac, move your joystick (just push it and let go) or tap your pedal(s) and then hit F1 (throttle shut off). Your ac will not zoom off when you then give it throttle AND move joy. Just some 'glitch' in the sim that won't go away. Yeah, turbo props are the worse for taxi speed adjust but I myself use a little reverse thrust using F2 (minu throttle=aprox '-5') to control taxi speed. No matter how good a pilot, or mechanic for that matter, you are in 'real world' you just can't modify the Sim. So YOU have to compensate / adjust. Like they say: 'You can't have eveything...what you see is what you get.. and all that 'stuff''.
Chuck B
Napamule