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Dash speed brakes

Discussion in 'Technical Talk' started by JordanD, Feb 10, 2012.

  1. milleR

    milleR Well-Known Member

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    fair enough, never been that far west. I stand corrected.

    Edit to ask: are they painted red to determine whether they're contaminated? Serious question.
     
  2. MikeD

    MikeD Administrator Staff Member

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    I think she flies them.
     
  3. milleR

    milleR Well-Known Member

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    hmm, well regardless, that first bit came off a bit more ass-hatish than I would have liked or should have written. Tact FAIL.
     
  4. SurferLucas

    SurferLucas Southern Gentleman

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    Actually the Outside Spoiler on the Q400's at QX have Red on the inside and Black on the outside (I remembered this in GS because they're UGA's colors)...as seen here:

    [​IMG]
     
  5. jynxyjoe

    jynxyjoe The Kickin' Chicken!

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    Yeah... unless I get displaced I have to go to the non grandfathered rates. You guys have any 1900's you're hiding from me?
     
  6. milleR

    milleR Well-Known Member

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    *checks coat pockets* nah man, nothing here
     
  7. RightSeatGirl

    RightSeatGirl KA'PLAH BITCHES!

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    About 3300 hours in the Dash spilt between the 100, 200 and 300. And there is a difference between the roll spoilers and the ground spoilers insofar as their functionality , they are two different control systems that share the same physical flight control surfaces and it was NOT inherited from the Dash 7. It was a completely new system from the ground up. You cannot deploy the roll spoilers as "air brakes" in either the 100 or 400 in flight. They are lift dumping devices with WOW and another two conditions, flight/taxi switch to flight and power levers at or near flight idle if that was what you were implying.

    And contrary to what you think, there are some 200's around with a Flight/Taxi switch and an activated ground spoiler system. In fact, a Bombardier flight test pilot that was shadowing our crews for a while told us that the old straight leg 300's had the option for the system available but no one ordered it which is why it was later discontinued ( contrary to the logical order the Dash 8 300 BTW was developed before the 200). The reason there are 200's with the system is because some operators self-modified their 200's to have it due to heavier than normal military payloads. The Q400 is certainly different in many respects to the prior models, but the need for ground spoilers is questionable at best. Just another example of Bombardier over-engineering.

    And every one of our 100's has the spoilers painted red! Ass hat-tish? Go fly a kite man!
     
  8. milleR

    milleR Well-Known Member

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    I certainly wasn't implying the use of spoilers as "air brakes" since that's not how they're employed. However, on the -400 the inboard and outboard spoilers are used for lateral control in flight and are the only flight control surfaces available in the event of an aileron cable jam. They are also used as lift dumping devices on landing.

    To my understanding, the 8-100 used a very similar wing and almost identical control surfaces to the Dash 7, hence the ground spoilers.

    I apologize for the tenor of my first post; my wife is right, I can really come across as an ass sometimes.
     
  9. MikeD

    MikeD Administrator Staff Member

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    Well, good thing is you're stand-up enough to admit to that. That's commendable in and of itself.

    Just proof before post! :D
     
  10. RightSeatGirl

    RightSeatGirl KA'PLAH BITCHES!

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    The utilization of the spoilers for roll control is the same across the whole Dash family as is the "design roots" of the fuselage and wing. But there was nothing mechanical that was carried over from the Dash 7 to the 8. The 7 did have a flight/taxi switch that did the same thing. But the system itself despite its identical function on the 8 was all new to design out several maintenance heavy flaws in the 7's systems namely the costly flap WOW auto retract feature. I'm not certain about the following but I believe I recall our guys that flew the 7 telling me the roll spoilers were all mechanical on the thing vs. the hydraulically actuated system on the 8.

    To answer the other question above the reason the F/T switch has the mag release is in case the crew forgets to flip it up before T/O (I've NEVER done that by the way...LOL). It's recommended by Bombardier for reason($) of wear and tear that the F/T switch should be manually actuated vs. letting it auto release.

    But again, the whole system is re-"dumb"dant..Once a Dash 8 is on the ground..it's done with lift LOL, a washing machine with wings would be more aerodynamic.....the props going into flight idle even without the power levers going over the gates putting the big fans into disc-ing is plenty on any runway you're gonna fly a Dash onto in a 121 operation. Our company even wanted Bombardier to develop an STC to eliminate the ground spoilers even on the 100's to save weight and maint. I've flown the plane several times with the system MEL'd and noticed zero difference though just to satisfy the pencil-pushing nature of the FAA we do take a slight weight penalty. And I do not miss the system on the 300's at all either.
     
  11. SurferLucas

    SurferLucas Southern Gentleman

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    I'll look tomorrow and see what the differences on the Q400's landing distances with spoilers and without.

    I like having them on the Q400, it a'int yo daddy's Dash 8
     
  12. RightSeatGirl

    RightSeatGirl KA'PLAH BITCHES!

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    I'd be a little surprised if the difference is all that significant, but I'd like to know for my own info even if I'm wrong so please follow up with that.
     
  13. SurferLucas

    SurferLucas Southern Gentleman

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    Probably not on the Q400, since we have anti-skid and reverse...once you get it on the ground, you can slow it down fairly quickly.

    Ok, so here's what I found in the performance manual: Airport elevation of less than 1000ft MSL
    @ 57K landing weight and NP1020 (not reduced Np of 850), at a Vref of 115kts the landing distance is - 4017ft
    @ the same weight, NP1020 and a Vref of 115kts with Ground Spoilers INOP - 4620ft
    @ the same weight, NP1020 and a Vref of 115kts with Anti-Skid INOP - 5978ft

    Going into somewhere like Santa Rosa (KSTS) with a runway of 5115ft, with the Ground Spoilers INOP and at MLW of 62,000lbs...you'd still be able to land with a little room to spare (4825ft appox).
     
  14. syntrikz

    syntrikz Well-Known Member

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    Wow that's Significantly higher than 2/300's... The 200's don't need brakes. 300's just barely...
     
  15. TUCKnTRUCK

    TUCKnTRUCK Doing the creep.

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    when ive had them inop, ive noticed the airplane likes to lift off the runway in gusts, and youve got a much better chance of activating the anti skid ( tons of fun in the Q) with initial brake application.

    it has a significant impact when the weather is less than ideal, and becomes a significant issues.
     
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  16. TUCKnTRUCK

    TUCKnTRUCK Doing the creep.

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    I hate autocorrect, I hate it that much more when it doesn't work. Oh well
     
  17. Pilotforhire587

    Pilotforhire587 Lycra Man

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    I have never actually paid enough attention to a Q400 or one of Piedmonts 100's to see if the spoilers come up on landing. I thought they just went up before take off as a test, much like we do a control test in ours and verify they work by use of the PFCS.
     
  18. Pilotforhire587

    Pilotforhire587 Lycra Man

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    HAHAHA I love the DC logic system.
     
  19. Autothrust Blue

    Autothrust Blue Flaps two, knees and nuts, aye aye

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    Stupid jet pilot here, but do you all use "reduced Np" for noise, and does that increase landing distance? (logic there: higher pitch = less drag)
     
  20. Cessnaflyer

    Cessnaflyer ?

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    In the king air it would add some distance because you would have to go fine pitch before you could reverse.
     

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