flyboy80
Posts: 1857
Joined: Fri Jul 13, 2001 8:10 am

Air Brakes On Props?

Mon Feb 09, 2004 9:31 am

I was simply wondering if there are any tubo prop commercial airliners "out there" that have air brakes? thanks for any info!
 
EMBQA
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Joined: Sat Oct 25, 2003 3:52 am

RE: Air Brakes On Props?

Mon Feb 09, 2004 9:46 am

Airbrakes...........??? As in...? for the landing gear/wheels.....?

No aircraft offer 'air brakes' that I'm aware of. Gases do not offer as much compressibility force as a liquid will.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
flyboy80
Posts: 1857
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RE: Air Brakes On Props?

Mon Feb 09, 2004 9:52 am

I mean the things on the wings which are refered to as air brakes, maybe they are sometimes called spoilers?
 
jayspilot
Posts: 238
Joined: Wed May 23, 2001 12:32 pm

RE: Air Brakes On Props?

Mon Feb 09, 2004 9:57 am

if you are talking about spoilers or speed brakes.. if so, yea some do.. i know the dash does...dornier does, beech doesn't .. not sure about ATR or SAAB. they arent' needed as much on a propeller aircraft, due to the fact that changing of the blade angle bringing back the power levers back creates a lot of drag and allows the planes to slow quick.. hope this answers your question
 
propjock04
Posts: 71
Joined: Fri Dec 12, 2003 1:53 am

RE: Air Brakes On Props?

Mon Feb 09, 2004 10:10 am

The Jetstream 41 has spoilers...used only on the ground.

Michael
 
access-air
Posts: 1576
Joined: Thu Sep 21, 2000 5:30 pm

RE: Air Brakes On Props?

Mon Feb 09, 2004 10:27 am

The Fairchild Hiller FH-227 used its main landing gear as a speed brake inflight to lose altitude quick as well as speed. This was also the case on some of the later versions of the Fairchild F-27 series....
Dont think that Fokker ever employed this feature on their F.27s....

Access-Air
Remember, Wherever you go, there you are!!!!
 
ScooterTrash
Posts: 553
Joined: Thu Aug 02, 2001 10:39 am

RE: Air Brakes On Props?

Mon Feb 09, 2004 10:40 am

I have flown the ATR as well as the Dash 8. No speed brakes per say on either aircraft. However, as was stated above, bringing the props to max rpm and the power levers to flight idle will result in the props becoming a very effective speed brake (high rpm, low pitch).
 
flyboy80
Posts: 1857
Joined: Fri Jul 13, 2001 8:10 am

RE: Air Brakes On Props?

Mon Feb 09, 2004 12:10 pm

Yeah, I have actually never noticed them on any props so to speak. BTW, are speed brakes and Spoilers the same thing?
 
jayspilot
Posts: 238
Joined: Wed May 23, 2001 12:32 pm

RE: Air Brakes On Props?

Mon Feb 09, 2004 12:32 pm

Speed brakes and spoilers are the same parts moving on the plane.. Flight spoilers don't deploy to the same angles as ground spoilers and and not as many of the panels move for flight. As for not noticing them on props, the only ones I've seen that have them are high wings so you can't see them from inside, only notice them while holding short behind them or watching one land
 
miles_mechanic
Posts: 132
Joined: Sat Sep 08, 2001 4:30 pm

RE: Air Brakes On Props?

Mon Feb 09, 2004 12:51 pm

Hey, as far as the Dash 8 goes, the 300 and 400 series do have spoilers.

As for actual air brakes, the Fokker F-27, was a pneumatic system, so the brakes, and other systems relied on air pressure to operate. It was a good system meaning you would never run out of supply, but in the winter months up here in Canada, it also became a curse when moisture would get in the lines and freeze. I have heard a few stories from friends who used to work on them and enjoyed working on them, but the winter time caused headaches.

Regards

Miles
 
SkydrolBoy
Posts: 334
Joined: Sun Sep 21, 2003 7:31 am

RE: Air Brakes On Props?

Mon Feb 09, 2004 2:17 pm

The Dash-8 100's and 200's also have spoilers
 
miles_mechanic
Posts: 132
Joined: Sat Sep 08, 2001 4:30 pm

RE: Air Brakes On Props?

Mon Feb 09, 2004 2:39 pm

Hey Skydrol, you are absolutely right about the Dash 8s', sorry about that, I ment to say that they were automatically activated on the 300 and 400 models, where the early ones it was a manual system, from what I had read about them.

Thanks for correcting me

Miles
 
L-188
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RE: Air Brakes On Props?

Mon Feb 09, 2004 7:59 pm

Most props can slow down just fine by pulling back the power, those props are pretty draggy.

Kind of like downshifting a car going down a hill.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
FredT
Posts: 2166
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RE: Air Brakes On Props?

Mon Feb 09, 2004 9:36 pm

No speed brakes or spoilers on the Saab 340/2000. I've heard that they can be rather slick at times, even with flight idle set.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
SlamClick
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RE: Air Brakes On Props?

Tue Feb 10, 2004 12:07 am

To be more accurate:

Spoilers "Spoil" the wing shape. They are hinged panels that deflect, usually up, from the surface of the wing. They have two modes:

  • Flight Spoilers kill some of the lift and allow quicker deceleration in level flight or steeper descents without airspeed gain. They may or may not include all of the available panels but will usually only allow partial extension.



  • Ground Spoilers include all panels to full extension. On ground contact, either strut compression or wheel spinup, kill most of the lift, transferring the weight of the plane to the wheels allowing effective braking. Remember, a moment earlier the wings were carrying the weight and the brakes would just lock the wheels if used.


  • Speed Brakes Are mounted on the fuselage or even the vertical tail in some military models. On the Fokker F-28 and F-100 and the BAe-146 they are the rearmost part of the fuselage, just below the rudder. They add drag but do not affect the lift being generated.

    Happiness is not seeing another trite Ste. Maarten photo all week long.
     
    bragi
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    RE: Air Brakes On Props?

    Tue Feb 10, 2004 12:23 am

    If you want to slow down a turboprop, it´s simply enough to reduce the power.

    The slow moving propeller blades act as a kind of air brakes.
    I don´t know about a turboprop fitted with air brakes.
    Muhammad Ali: "Superman don’t need no seat belt." Flight Attendant: "Superman don’t need no airplane, either."
     
    SlamClick
    Posts: 9576
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    RE: Air Brakes On Props?

    Tue Feb 10, 2004 12:46 am

    Bragi

    True enough. The drag of those props does a good job.
    Turboprop with speed brakes, one model of the Grumman OV-1 Mohawk. Could not find a picture of the brakes in this db though.

    Happiness is not seeing another trite Ste. Maarten photo all week long.
     
    ScooterTrash
    Posts: 553
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    RE: Air Brakes On Props?

    Tue Feb 10, 2004 10:50 am

    True about the Dash 8's spoilers. They function in two regimes: In flight, they act as roll control augmentation and on the ground they act as lift dumping devices. There are four panels on the upper wing. They all act to assist roll control below 140 knots TAS. Above 140 knots, only the inboard spoilers operate. They are not used as speed brakes during flight.

    The Dash 8-100 and some -300's are equipped with another set of panels, called "ground spoilers" to further dump lift during the landing roll out. Many operators have deactivated these to save maintaining costs.

    The ATRs also have "spoilerons" to assist with roll control.
     
    MYT332
    Posts: 7285
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    RE: Air Brakes On Props?

    Wed Feb 11, 2004 1:35 am

    The Dash7 have them to assist with STOL.
    -
    Alex

    One Life, Live it.
     
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    Francoflier
    Posts: 3784
    Joined: Wed Oct 31, 2001 12:27 pm

    RE: Air Brakes On Props?

    Wed Feb 11, 2004 12:46 pm

    The LET 410 has spoilers on the wing. They are used to shorten landing distance and may only be deployed on the ground or at a max "altitude" of 2 feet above the ground, but never during flight... (a friend of mine who tried could tell you that...)

    The Jetstream 31 have what they call a "lift dump" which simply consists of the wing flaps going down almost vertical after touchdown. (Only on the ground too..)

    The F-227 used its main gear as a speed brake, as mentioned above, which very often caused the crews to receive warning from other caring crews saying that their nose gear hadn't come down...
    BTW, Fokker enthusiats are never out of compliments for that pneumatic system, but in the end, it caused more trouble than it solved. As in: too many leaks, that are impossible to find, water freezing in the lines (mentioned above) and the all too common case of the A/C collapsing on the ground because someone forgot to put the ldg gear pins on and all the air finally leaked from the actuator...

    Just a few more example of "speed brakes" or "lift dump" devices on turboprop but I don't know of one having proper "speed brakes" either...
    I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.

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