united319
Posts: 446
Joined: Mon Jul 03, 2006 1:07 am

Turbo Prop Taxiing

Mon Feb 04, 2008 9:04 pm

Hello all,

Whenever I fly a turboprop such as a Dash 8, EMB-120, Saab 340 etc it always seems to taxi extremely fast. I tried messing with the feathering and that doesnt help at all. Any advice?
It's Time To Fly
 
wilco737
Posts: 7279
Joined: Sun Jun 20, 2004 12:21 am

RE: Turbo Prop Taxiing

Mon Feb 04, 2008 9:12 pm



Quoting United319 (Thread starter):
I tried messing with the feathering and that doesnt help at all. Any advice?

Using the brakes could help! Big grin

It should help if you set the props to feather, that they do not produce any forward thrust or just pull them slightly into reverse pitch... Then you should slow down...

WILCO737 (MD11F)
 airplane 
 
jamesbaldwyn
Posts: 747
Joined: Wed Sep 28, 2005 12:04 am

RE: Turbo Prop Taxiing

Mon Feb 04, 2008 11:47 pm

Sounds like a good excuse for priority taxiing at the airports Big grin
 
kcrwflyer
Posts: 2525
Joined: Tue May 18, 2004 11:57 am

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 3:44 am

Idle thrust and ride the brakes if you have to. I usually taxi with one engine feathered.
 
wilco737
Posts: 7279
Joined: Sun Jun 20, 2004 12:21 am

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 7:06 am



Quoting KcrwFlyer (Reply 3):
ride the brakes

Ride the brakes? Not good, they heat up pretty fast! Better let the aircraft accelerate then hit the brakes until pretty slow again and then release them again.


WILCO737 (MD11F)
 airplane 
 
ZKSUJ
Posts: 6804
Joined: Tue May 18, 2004 5:15 pm

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 11:34 am

Just cruise on idle once you have bumped up the power and your speed is sufficient. This should allow you to not use brakes till turning or stopping
 
jamesbaldwyn
Posts: 747
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RE: Turbo Prop Taxiing

Tue Feb 05, 2008 3:58 pm

Don't some aircraft taxi using one engine ? To save fuel and to control speed I imagine ?
 
9VSIO
Posts: 653
Joined: Tue Dec 19, 2006 5:00 pm

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 8:44 pm



Quoting Jamesbaldwyn (Reply 6):
Don't some aircraft taxi using one engine ? To save fuel and to control speed I imagine ?

This is a topic that gets frequently brought up in tech/ops, and the answer is maybe - it all depends.
Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
 
Ps76
Posts: 1015
Joined: Tue Jun 01, 2004 7:52 pm

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 8:58 pm

Hi,

I'm assuming this is Flightsim(?) (I have 0 rw experience flying turboprops!) With me I also get this with Fs2004, like the plane doesn't move until you increase N1 and then it suddenly rushes forward. One thing I found that helped me was to reduce the mixture as much as possible (Ctrl-shift-F2?) without the engine shutting down (in the default Cessna Caravan throttle panel it would be reducing the mixture lever from high idle to low idle). Have found it helps a little for taxiing until I reach the runway when I (hopefully remember to!) reset to full idle.

Hope it might help a little.

P.

Edit: I just reread this post and realised that the OP is probably talking about real flying in which case please ignore, or like we like to say in flightsim, "please do not use for real world navigation"!    

[Edited 2008-02-05 13:23:34]
 
jamesbuk
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RE: Turbo Prop Taxiing

Tue Feb 05, 2008 11:10 pm



Quoting Ps76 (Reply 8):

I doubt it - If the OP is a real world pilot - and doesnt know how to taxi is aircraft I'd be slightly worried!! haha.

But yeah what you said is pretty much right, put it into a low idle by either pulling the prop control back, or pulling the mixture back.

Rgds --James--
You cant have your cake and eat it... What the hells the point in having it then!!!
 
osu_av8or
Posts: 82
Joined: Mon Oct 08, 2001 10:15 am

RE: Turbo Prop Taxiing

Tue Feb 05, 2008 11:45 pm

In real life, I've only flown two turbo props, both with PT-6 engines. Both the F90 King Air (Be-9T) and the Pilatus PC-12 are routinely taxied with the power lever(s) over the beta gate. If you fail to do so, you will find yourself riding the brakes all the way to the hold short line. This isn't good for the brakes, and certainly isn't good if you have to reject a takeoff (hot brakes = higher possibility of failure).

This is certainly one thing the sim got right.
 
kcrwflyer
Posts: 2525
Joined: Tue May 18, 2004 11:57 am

RE: Turbo Prop Taxiing

Wed Feb 06, 2008 12:42 am



Quoting WILCO737 (Reply 4):
Ride the brakes? Not good, they heat up pretty fast! Better let the aircraft accelerate then hit the brakes until pretty slow again and then release them again.

Only if he has to. Like i said, I go with one engine feathered.
 
united319
Posts: 446
Joined: Mon Jul 03, 2006 1:07 am

RE: Turbo Prop Taxiing

Wed Feb 06, 2008 2:59 pm

Ill try the one engine feathered technique. Ive tried taxing on one egine before with a regular airliner and it always veers to the direction that the one engine is running on. I know this will happen in real life but not to the extent that it happens in FS.
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cptspeaking
Posts: 567
Joined: Mon Apr 24, 2006 2:49 pm

RE: Turbo Prop Taxiing

Thu Feb 07, 2008 9:59 pm

I fly a King Air 300 in the real world, and in order to not do what you've described, we taxi around in low idle (mixture control in FS), and when we start to get fast, lift the throttles over the gate into beta range. Beta is basically where the throttle controls the pitch of the blades instead of the prop lever and governor. By putting it into beta, you're effectively making the blades flat (90 degrees from feather), which causes little to no thrust and lots of drag. We did the math one time in the cruise just for giggles and figured out that when the props are in beta on the 300, the disc area is equivalent to about 4 sheets of plywood. That's a lot of drag! When you're riding on a turboprop next time, you can tell when the pilots select beta range by the sound...you'll know it when you hear it. Unfortunately, I haven't run across any plane in FS that accurately simulates beta range.

The closest to real-life turboprop in FS is by far the Aeroworx King Air 200. When I'm flying this one, after I start the engines, I'll pull the condition levers (mixture) back to ~70%. This puts the engines in a low idle state. Otherwise, you'll go speeding around on the ground and then won't be able to slow down on final and will float forever in the flare.

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