The Buccaneer
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The Buccaneer
Reading a piece on the aircraft and says that it was cleared for aileron and barrel rolls, and rolls off the top - but loops were not permitted. What was the nature of the problem? (Article written by Grp Cpt Tom Eeles)
I can't remember. But a pilot who'd tried it and who kept the ADD on the 'steady' note att he top of the loop told me that the aircraft accelerated at an alarming rate from the inverted position and lost an enormous amount of height in the second half of the loop - he said he'd never try it again!
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Beagle has the reason exactly. The RAE Buccanneers, the original Green & Yellow beauties, had clearance to fly loops for a trial, the reason for which escapes me after all the years. Enter at 5,000ft & 550KIAS not a lot of KIAS over the top then rapidly building KIAS and, significantly, Mach No on the way down. Providing the driver did not allow the speed to run away, effective air brakes on the Bucc, it was not dramatic. Let the speed get away, then even with full air brake the final 90 degs of manoeuvre back to level flight was a touch unpleasant - particularly for the rear-seater.
I guess I should also say that I am talking clean aircraft here, or in the RAE aircraft case, cameras only.
lm
I guess I should also say that I am talking clean aircraft here, or in the RAE aircraft case, cameras only.
lm
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Hello All. I'm new and just registered. The problem after passing the top of the loop is gaining to much speed and nearing the speed of sound. The condition, once know as "compressibility" caused severe buffeting, loss of control, and could cause the stick to beat your legs black and blue. It was a serious condition avoid in the P-47 Thunderbolt, among other aircraft.
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Brian
Your question aroused my curiosity.
Explanation from Tom Eeles today:
FL
Reading a piece on the aircraft and says that it was cleared for aileron and barrel rolls, and rolls off the top - but loops were not permitted. What was the nature of the problem? (Article written by Grp Cpt Tom Eeles)
Explanation from Tom Eeles today:
"The reason why full loops were never cleared for the Buccaneer was that, firstly, the tailplane was fairly small and had insufficient authority to generate a high enough rate of pitch to guarantee recovery as the aircraft accelerated downhill on the second half of the manoeuvre, and secondly, the aircraft could accelerate very rapidly when going downhill and quickly reach its limiting Mach No of .95. If this was exceeded by a fairly small margin, the manufacturers believed the whole tail would detach. Thus pull ups into a roll off the top, with the airspeed/Mach number decreasing, were OK, but not the opposite.
That said, with care a loop could be done perfectly safely.
That said, with care a loop could be done perfectly safely.
Last edited by Flying Lawyer; 3rd May 2007 at 08:34.
ZH - only spotters called the Buccaneer the 'Brick'.....
FL - I had a feeling the pitch authority of the tailplane might have been the main reason - good to have it confirmed by such an authoritative source.
Interesting that he said that it could be looped 'perfectly safely'....I doubt whether many people who did loop it did so twice!
FL - I had a feeling the pitch authority of the tailplane might have been the main reason - good to have it confirmed by such an authoritative source.
Interesting that he said that it could be looped 'perfectly safely'....I doubt whether many people who did loop it did so twice!
Last edited by BEagle; 3rd May 2007 at 05:44.
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FL, many thanks - no doubt about Pprune, it goes right to the source. 
BEagle, from the way it was put I read "could be done safely if you really were on top of things (his "with care" statement) but not something you would want the average squadron pilot trying". Much as your mate experienced in your first post.
BEagle, from the way it was put I read "could be done safely if you really were on top of things (his "with care" statement) but not something you would want the average squadron pilot trying". Much as your mate experienced in your first post.
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Lightningmate,
"The RAE Buccanneers, the original Green & Yellow beauties, had clearance to fly loops for a trial, the reason for which escapes me after all the years."
Could it be connected to toss bombing? Our ex-project pilot recalled doing similar evolutions in a CF-104 (a half-loop) only, in his case, he ended up with the "shape" still attached.....
"The RAE Buccanneers, the original Green & Yellow beauties, had clearance to fly loops for a trial, the reason for which escapes me after all the years."
Could it be connected to toss bombing? Our ex-project pilot recalled doing similar evolutions in a CF-104 (a half-loop) only, in his case, he ended up with the "shape" still attached.....
I was certainly never brave enough to try a loop in the Bucc - I was far too crap! We did a bit of tailchasing during my short struggle with the OCU course - and a lot of toss manoeuvres as well as tactical low level formation at which it was utterly superb.
For medium toss it was never necessary to get close to the vertical - and the excellent roll rate (second only to the Gnat!) was used to roll to over 90 deg AOB to pull down to the horizon to stop the climb, then a hard turn to escape. It formed part of the Buccaneer IRT in the Hunter T7A/T8B, if I recall correctly.
For medium toss it was never necessary to get close to the vertical - and the excellent roll rate (second only to the Gnat!) was used to roll to over 90 deg AOB to pull down to the horizon to stop the climb, then a hard turn to escape. It formed part of the Buccaneer IRT in the Hunter T7A/T8B, if I recall correctly.
Tailplane authority? One of our drivers managed to pull the thing off trying to avoid a police helicopter in Germany at 500ft. Martin Baker letdown worked fine though thank goodness.
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ICT_SLB,
Certainly not true Toss-Bombing related, although it may have been related to a proposed update the the aircraft Master Reference Gyro. We are talking nearly 30 years ago here.
chevvron,
That sounds unpleasantly familiar, if you remember, what was the aircraft serial involved in your recollection? I might dispute your detached tail plane assertion.
lm
Certainly not true Toss-Bombing related, although it may have been related to a proposed update the the aircraft Master Reference Gyro. We are talking nearly 30 years ago here.
chevvron,
That sounds unpleasantly familiar, if you remember, what was the aircraft serial involved in your recollection? I might dispute your detached tail plane assertion.
lm
Just to add a little more detail, having had a "close friend" who looped the Bucc many times (I have to say that as Tom Eeles was the CFI when I was a student on the OCU). The problem is that tailplane power reduces markedly at high Mach numbers. If the speed is allowed to increase too much during the second half of a loop and you are at medium level, the resulting high Mach number results in little g being available, even at full back stick, and thus there will be an excessive altitude loss. As a complete loop was not required for the role of the aircraft, it did not have to be cleared as a permitted manoeuvre. As there was a safety related problem if the manoeuvre was mishandled, it was formally prohibited.
However, the first time that "my friend" tried it (from a 5000 ft, 550 KIAS entry), he selected idle and half airbrake as the nose came down through the horizon and levelled off in a very controlled fashion some 2000 ft above entry altitude. Having established a safe recovery technique, his next attempt was just to select idle as the nose came down through the horizon and to fly a controlled pull in the final quarter to level at entry altitude, typically about 100 KIAS below entry speed. This was repeated whenever a suitable opportunity arose although it did cause consternation for some navigators who had never seen the manoeuvre!
On an allied subject, the Aircrew Manual had a graph of minimum entry speed for a roll-off-the-top as a function of weight and altitude, the absolute minimum speed being 530 KIAS (from memory). During a display season I was happy with a clean aircraft at light weight to ROT from 480 KIAS and to vertical roll from 530 KIAS. I did work up a display sequence that commenced with a half horizontal 8 (half cuban in aerobatic terms), rolling on a 45 degree down line. However, that display requirment was cancelled so it was never seen in public and making base height was very critical on the angle of the down line. That display also included a 15-10-10 gear down barrel roll but that is another story!
However, the first time that "my friend" tried it (from a 5000 ft, 550 KIAS entry), he selected idle and half airbrake as the nose came down through the horizon and levelled off in a very controlled fashion some 2000 ft above entry altitude. Having established a safe recovery technique, his next attempt was just to select idle as the nose came down through the horizon and to fly a controlled pull in the final quarter to level at entry altitude, typically about 100 KIAS below entry speed. This was repeated whenever a suitable opportunity arose although it did cause consternation for some navigators who had never seen the manoeuvre!
On an allied subject, the Aircrew Manual had a graph of minimum entry speed for a roll-off-the-top as a function of weight and altitude, the absolute minimum speed being 530 KIAS (from memory). During a display season I was happy with a clean aircraft at light weight to ROT from 480 KIAS and to vertical roll from 530 KIAS. I did work up a display sequence that commenced with a half horizontal 8 (half cuban in aerobatic terms), rolling on a 45 degree down line. However, that display requirment was cancelled so it was never seen in public and making base height was very critical on the angle of the down line. That display also included a 15-10-10 gear down barrel roll but that is another story!
lightningmate: Not sure it may have been XV344 ex FAA(If someone has a list of RAE Buccs I may be able to be more accurate). Pilot told me he'd pulled 9g avoiding the helicopter. Are you ex RAE?
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chevvron,
Certainly not XV344, she sits resplendently in the middle of the QinetiQ site at Farnborough.
I will offer you XN975, Buccaneer Mk 2 prototype.
I have worked at RAE Farnborough, serving RAF at the time, and wearing a green coverall.
lm
Certainly not XV344, she sits resplendently in the middle of the QinetiQ site at Farnborough.
I will offer you XN975, Buccaneer Mk 2 prototype.
I have worked at RAE Farnborough, serving RAF at the time, and wearing a green coverall.
lm
Don't actually recall that one; I know we had at least two delivered in when withdrawn from FAA service and '344 was one; then of course there were three special builds '986, '987, '988. Maybe '975 had only recently arrived when it met it's end? Can't see '344 from my viewpoint; all we can see is a Puma and a Jaguar.
Obviously our paths must have crossed at some time; I may even have flown with you!
Obviously our paths must have crossed at some time; I may even have flown with you!
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chevron,
You have clarified it was an RAE aircraft asset; hence, it was XN975 on 14 June 1978. A day engrained in my psyche!
The empennage did separate but not during any of the extreme manoeuvring. It was broken away as the aircraft impacted the ground and survived the fire by being deposited some 100ft behind the main impact area.
Regards
lm
You have clarified it was an RAE aircraft asset; hence, it was XN975 on 14 June 1978. A day engrained in my psyche!
The empennage did separate but not during any of the extreme manoeuvring. It was broken away as the aircraft impacted the ground and survived the fire by being deposited some 100ft behind the main impact area.
Regards
lm