Mr Spaceman
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"Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 5:28 am

Hi guys.

I'm very curious about why the spoilers/speedbrakes (I'm not sure what they're called) on the Avro Vulcan Bomber are designed the way they are. They look very unique compared to other types of aircraft.

Some questions I have are...Why is so much air allowed to flow through them? (this is how it apears).

What are they actually called?

Are they used only as speedbrakes, or are they ground spoilers too?

Do they swing up into position, or do they pop straight up?

Here's a few photos of the Vulcan with them extended. Note how they are also located on the bottom of the wing.

Click for large version
Click here for full size photo!

Photo © Paul Robinson



Click for large version
Click here for full size photo!

Photo © Paul Robinson


Also, are there any other aircraft that have these types of spoilers/speedbrakes? I found a photo of a SUD Super Caravelle-10B3, and one of it's spoilers seems to look very similar to the ones on the Vulcan Bomber. Are the design of these unique spoilers on these 2 aircraft the same?

Here's a close-up shot of this unique spoiler on the Super Caravelle's wing.

Click for large version
Click here for full size photo!

Photo © Erik Bentsen



Click for large version
Click here for full size photo!

Photo © John P. Stewart


Any info about these spoilers/speedbrakes is much appreciated.

Chris  Smile


"Just a minute while I re-invent myself"
 
david b.
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RE: "Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 6:10 am

Dont know but on some planes, they are used as spoilerons, that is they are a combination of spoilers and alierons. They decrease lift on one wing. The wing dips and the plane banks. The sopilerons work by
lifting up on one side. Poping up I would assume, give them the ability to act faster. Spring-accuation? Yawn Big grin
Teenage-know-it-alls should be shot on sight
 
Mr Spaceman
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RE: "Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 6:42 am

Hi David B. Thanks for your reply.

I know exactly how spoilerons and roll spoilers work. Usually spoilerons are located out toward the wingtips. The ones on the Vulcan bomber are located over the engines, within the first quarter from the root of each wing's span. Plus, if you look at the photos, you'll see that these objects are extended on both wings at the same time, on both the top and bottom surfaces. I'm not saying that you're incorrect, it's just an observation. I'm also aware that the wing itself on the Vulcan is quite unique, so this unusual looking feature doesn't surprise me. However, the wing on the Super Caravelle isn't a huge delta wing like the Vulcan's, and it appears to have the same type of spoilers/speedbrakes/airbrakes or whatever they're called.

Can you tell me what aircraft use these things as spoilerons?

I looked closer at the photo of this device while extended on the wing of the Caravelle, and it obviously swings up into position...so your mention of spring-accuation sounds good to me. Perhaps it's the same technique on the Vulcan.

Chris  Smile
"Just a minute while I re-invent myself"
 
david b.
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RE: "Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 7:14 am

I know that the B52 uses them. No commercial aircraft I know of uses them by themselvers. Some jets(not sure which ones at this time) uses them with conjunction with the aelirons. Guess they are used on military aircraft because they act faster.  Nuts
Teenage-know-it-alls should be shot on sight
 
Mr Spaceman
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RE: "Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 7:42 am

Hi David B.

Yes sir you are right. Some models of the B-52 did infact use ONLY flight spoilers (spoilerons) to control bank angle. These were the G and H models. However, the spoilerons used on the B-52 were made of "solid" panels.

One of the main reasons I'm so curious about the spoilers on the Vulcan and the Super Caravelle is because of their design. They are not "solid" panels. At least, not completly. You can look at the photos and see that the lower portion of these spoilers is missing. That's why I've been calling them unique.

I wonder why these spoilers are designed so that air can flow right through them? Dosen't that defeat the whole purpose?

Maybe it's just older technology. Perhaps these aircraft didn't need a solid panel in order to achieve their aerodynamic goal.

If you look at the close-up photo I posted of the wing of the Caravelle airliner, you can see this strange looking device which allows air to pass through it, in between to normal looking spoilers that are built with solid panels. I think this is very interesting. I suspect this type of spoiler might have it's own special name.

P.S. Thanks for your replies.  Big thumbs up

Chris  Smile/happy/getting dizzy
"Just a minute while I re-invent myself"
 
VC-10
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RE: "Unique" Spoiler/Speedbrake Question?

Tue Dec 18, 2001 11:30 pm

Vulcan Airbrakes

The Slat type airbrakes are electrically operated by two electric motors, one normal, one emergency.


The airbrakes have three extended positions.

1) Medium Drag 35 degs

2) High drag (u/c up) 55 Degs

3) High Drag (u/c down) 80 Deg. Transition from 55 to 80 degs is automatic when the u/c is lowered, bur raising the u/c does not retract the airbrakes to 55 Deg.

Sustained flight with airbrakes extended against engine power is not recommended


Airbrake Charecteristics.

At high a/speed at lower alts, the airbrakes are very effective and cause only mild buffet in the high drag posn, with a marked nose-down change of trim. At higher Alts, close to the limiting mach no., the high drag position produces marked buffet, accompanied by severe airframe vibration, as well as the nose-down change of trim. If the limiting mach no. is exceeded, this vibration make the cockpit instuments unreadable. At low airspeeds, the airbrakes are much less effective but do assist during the appr & ldg. the airbrakes take approx 5 secs to move from in to medium drag and a further 2 secs from medium to high drag.

Taken from the Aircrew Manual.
 
avionic
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RE: "Unique" Spoiler/Speedbrake Question?

Wed Dec 19, 2001 12:43 am

I only know about commercial planes, but the definition of a speedbrake, is a panel extended in the airflow (being on the wing or on the tail like f.ex. F28) that does not disrupt (too much) of the lift. Spoilers are made to "spoil" the lift, the bonus is it also increases the drag and slows the A/C down. But oin the professional world, the terms speedbrakes and spoilers are used generously.....talking about the caravelle, you can see the speedbrakes are perforated with holes.....some call it the french fries iron.....keeps the border layer on the wing intact...and thus the lift also.....I am not gonna go into aileron/spoiler mixers and flt/grd spoilers.....hope it helped you  Smile
 
EGNV
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RE: "Unique" Spoiler/Speedbrake Question?

Wed Dec 19, 2001 2:15 am

If you want to know about military aircrft, then why not try posting in the military aviation forum here?
I know you already have your answer but well thats an idea - dont forget about the military sections.
EGNV.
 
flyDLjets
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RE: "Unique" Spoiler/Speedbrake Question?

Wed Dec 19, 2001 3:07 am

The only civilian airpane that uses spoilerons to turn instead of conventional ailerons is the Mitsubishi MU-2.
 
Mr Spaceman
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RE: "Unique" Spoiler/Speedbrake Question?

Wed Dec 19, 2001 3:10 am

Hi guys. Thanks, to you all for helping to answer my questions about these speedbrakes.

>VC-10, that was great information you gave me...right from the manual! Now I know that they are infact "airbrakes" and have 3 extended positions, etc. Pretty interesting how these airbrakes will cause so much airframe vibration, if extended past the limiting mach #, that you can't read the cockpit intruments. It must have been fun doing those flight test.  Smile/happy/getting dizzy Thank You Sir.

>Avionic, thanks for your info. Now I understand why airflow is alowed to pass underneath the solid panel on the Vulcan's airbrakes as well as the small perforated panel on the Caravelle's airbrakes. It's to keep the airbrakes from disturbing the boundary layer of airflow, thus the lift, over that portion of the wing, while still creating drag. A solid one-piece spoiler can't do this (and isn't suposed to). I love learning about aerodynamic devices on aircraft. Thank You Sir.  Big thumbs up

>EGNV, regarding your mentioning of the military forum...If you check my profile, you'll see that one of the thread starters of mine in that forum was another question about the Vulcan bomber. I'm very aware that [this] question could have been posted in the military forum, however, I chose to post it in this technical forum because it invoved a commercial airliner as well...the Super Caravelle. I like the military forum, because I've always LOVED military aircraft, but part of this post included the question about "if any airliners used this unique type of spoiler"? Thank You, for your reply Sir.  Smile

Chris  Smile
"Just a minute while I re-invent myself"
 
Mr Spaceman
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RE: "Unique" Spoiler/Speedbrake Question?

Wed Dec 19, 2001 3:44 am

Hello FlyDjets.

Years ago I used to refuel a Mitsubishi MU-2 several time a week. It was a dedicated "Medivac" aircraft. However, I never noticed that it didn't have ailerons, while I was topping her up. Very interesting indeed.

You can clearly see in these 2 photos that there are no ailerons on this MU-2.


Click for large version
Click here for full size photo!

Photo © John Davies



Click for large version
Click here for full size photo!

Photo © John Davies


P.S. I remember (15+ years ago) reading about how it was practically imposible to recover an MU-2 from a spin...after one went down over Chicago. I wonder if this had anything to do with the arrangement for controlling bank?...using ONLY spoilers.

Chris  Smile
"Just a minute while I re-invent myself"
 
flyDLjets
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RE: "Unique" Spoiler/Speedbrake Question?

Thu Dec 20, 2001 12:55 am

Mr. Spaceman,

In conventional spin recoveries, ailerons are placed in the neutral position. So I can't see why that would make it too impossible to recover from a spin. But, maybe if one of the spoilers got stuck in the up position and caused a roll and that wing to stall, then that would cause a spin. Another factor is if it was a Vmc related spin, where the pilot experienced engine failure and stalled the airplane the airplane would then enter a spin easily. But that's not to say that the spoilers had nothing to do with it, I honestly don't know. All I know is those Garret Turboprops are too damn loud and the MU-2 is a runway hog. It rotates at 120 kts!! I would love more info on that crash, do you know the particulars? Like NTSB report?
 
Mr Spaceman
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RE: "Unique" Spoiler/Speedbrake Question?

Thu Dec 20, 2001 2:57 am

Hi FlyDLjets.

Yes sir I agree with you about those Garret engines being so dam loud. Even with headsets on, I'd be half deaf and the noise and vibration would start vibrating through my whole body. Mind you, I still loved it.

Regarding the particulars about the MU-2 that went down over Chicago, all I can say is that the article I read about the spin characteristics of the MU-2 (as a result of the Chicago crash), was in FLYING magazine in the mid 80s.

About info from an N.T.S.B. report on this accident...very simple, I'll start hunting for it, and I will find it.

Chris  Smile

"Just a minute while I re-invent myself"

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