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-   -   Question to Vulcan drivers (https://www.pprune.org/military-aviation/592188-question-vulcan-drivers.html)

JammedStab 14th Mar 2017 19:34

Question to Vulcan drivers
 
Take a look at this video at 4:35. It appears to me that there are spoilers/speed brakes extended for the takeoff. What are those extended panels on top of the wings for?

https://www.youtube.com/watch?v=PBJ99bIhAVk


H Peacock 14th Mar 2017 19:53

A Vulcan's Airbrakes extended from the top and bottom of the wing. I'm not sure why they would be out for takeoff, but perhaps that clip was from a t&g.

MPN11 14th Mar 2017 19:57

... where thrust as significantly greater than drag, so retracting is not a critical checklist item? :)

I shall ask my B-I-L, who use to drive the Beast.

Pontius Navigator 14th Mar 2017 20:17

IIRC we would leave undercarriage down and airframe too when pounding the circuit. Obviously there is more drag but at the same time it means the engines will be operating at higher and more responsive power settings. Engines at flight idle could take quite a while to develop full power. I am sure BEagle will be along with the facts.

Looking at the video, that was a Mk1 and i think the brakes were at mid-drag. The B47 used to use a drag chute in the circuit to keep engine power high as well.

NutLoose 14th Mar 2017 20:22

Wouldn't that also be for cooling the brakes etc

dragartist 14th Mar 2017 21:59

PN I have a nice pic of a B47 with the drag chute out.

scorpion63 14th Mar 2017 22:36

Definitely a B1 not B1a

rlsbutler 14th Mar 2017 23:04

JammedStab pointed up the clip at 4:35; the same clip is glimpsed at 0:42.

I had about two years as a very undistinguished Vulcan captain some forty years ago. The brain is going, of course, but I just do not remember taking off or rolling with the airbrakes out. It seems now to have been quite unreasonable (bad airmanship, plain untidy) to do so. The clips will have been taken from some sort of test or display sequence.

The airbrakes had a puny effect at circuit speeds although, as PN says, on a balanced approach their use allowed a higher engine setting where the engines would be more responsive. Moreover the direct drag that they generated slightly reshaped the drag curve, so that the speed at which you could find yourself behind the curve was a smidgeon lower.

On an ordinary takeoff there was absolutely no reason to have the airbrakes out – they would just generate drag to oppose the huge thrust we always used to escape the surly bonds. That would not matter much except that there must be some sort of risk that we would leave them out for rest of the trip. What was good for the takeoff was good for the roller; it only took the flick of a switch to bring the airbrakes in as you brought up the power.

Pontius Navigator 15th Mar 2017 13:12

Looking again, the airbrakes are at mid to low drag. I wonder if, as ris says, it was part of a sequence, indeed could they have been travelling after a roller.

50+Ray 15th Mar 2017 19:22

In my view they are travelling in after a roller.

mahogany bob 16th Mar 2017 08:35

The airbrakes were extended on all normal approaches to land because as PN stated the engines would then be in a higher (more responsive) setting (with the gear down the airbrakes moved to a higher drag position than with the gear up.) Note: the Vulcan has no flaps which solved the problem on ' conventional ' ac . Also with airbrakes out the nose was lower which gave the pilot a much better 'view' of the runway.
Occasionally approaches were practiced airbrakeless - these were quite tricky as it was very difficult to control the speed without reducing power to a low (irresponsive) setting. Also as the ac nose was unusually high on landing airbrakeless this meant that you had to be careful not to 'round out' too much which could result in a long 'float' and possibly a 'tail scrape' not to mention losing good sight of the runway!

Obviously the airbrakes would be IN for T/O and selected IN on rollers - which was probably happening in this case??

mahogany bob 16th Mar 2017 08:45

Also - on an airbrakeless approach - you had to watch the rate of descent very carefully - as with the high nose attitude it was very easy to lose height rapidly without noticing visually and in the worst case undershoot!

Pontius Navigator 16th Mar 2017 09:09

MB, which accounted for one AHJ, IIRC, who collected the Scampton approach lights before landing.

PS, regarding runway view at high pitch angles, the Mk 1 could hold a much higher nose up when aerodynamic braking, which must have been very interesting for new pilots.

rlsbutler 16th Mar 2017 09:44

PN – I do not remember who AJH was but I briefly shared his problem on the Scampton approach. We might both have been going through the OCU, for all I know.

The point about operating behind the drag curve was that a slight drop in speed (really of course the reflex increase in angle-of-attack) demanded a very great increase in power. So in my case I did not collect the approach lights (as I remember it) but I burned a lot of wheat nearest the touch-down. For some reason I cannot explain, the admin consequence did not impact much on me but my innocent trainee co-pilot was sacked.

Ex-Canberra, I had no problem with aerodynamic braking which was a way of boasting that you had landed at the right point and speed. I would be interested to know what was the difference in this respect between the Mk 1 and my Mk 2.

Pontius Navigator 16th Mar 2017 11:07

The difference I only observed at Finningley where the Mk 1 was relegated to a training role. It could pull considerably more braking without that bulbous tail.

One thing I don't remember is the tail brake chute storage. I have a vague memory of it being at the side of the tail fin. Anyone know differently?

The Oberon 16th Mar 2017 11:43

P.N.

It was on top, in a hopper between the fin trailing edge and the Red Steer and a bloody nuisance to fit.

Pontius Navigator 16th Mar 2017 11:52

TO, that was Mk1a/2. The Mk 1 only had Orange Putter.

The Oberon 17th Mar 2017 09:44

PN
Apologies, the only reference I can find says that the Mk1 deployed a brake chute from the RHS of the tail cone. As you say it was relocated to the top surface hopper on the 1A and 2.

Pontius Navigator 17th Mar 2017 10:29

TO, that fits my vague memory of it being perhaps nearer the rudder.

Lonewolf_50 2nd May 2017 02:03

speaking of questions only vulcan drivers/crew would know an answer to, one of you may be interested in this one. If so, it might be helpful for them to hear from someone who was involved.

If not, understood.


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