The Buccaneer's Deck Takeoff Button - Seeking Details
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The Buccaneer's Deck Takeoff Button - Seeking Details
Hi
I'm looking for technical details of the Buccaneer's Deck Takeoff Button.
I know it was a button which allowed an automatic retraction of the Landing Gear as soon as weight was off wheels, primarily intended for helping the underpowered S1 to operate from small aircraft carriers but I'm seeking a bit more;- what AP is it described in, anyone know the system switch logic, was it wired up in latter service because it had proven unsafe, how was the system deselected in the event of an aborted takeoff?
There are pictures which seem to show it's use on RAF aircraft;- official use?
Anyone know if other aircraft used a similar system?
Any Information will be really appreciated.
I'm looking for technical details of the Buccaneer's Deck Takeoff Button.
I know it was a button which allowed an automatic retraction of the Landing Gear as soon as weight was off wheels, primarily intended for helping the underpowered S1 to operate from small aircraft carriers but I'm seeking a bit more;- what AP is it described in, anyone know the system switch logic, was it wired up in latter service because it had proven unsafe, how was the system deselected in the event of an aborted takeoff?
There are pictures which seem to show it's use on RAF aircraft;- official use?
Anyone know if other aircraft used a similar system?
Any Information will be really appreciated.
I don't know about he S1 or deck take offs but in the RAF S2 this was a widely spread myth. If we wanted the gear up quickly because of performance limitations (i.e. Gibraltar) or to impress at a display the pilot simply kept pressure on the retraction button and when the weight came off the wheels-the gear came up!
Last edited by Timelord; 18th Aug 2017 at 21:41.
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This Blackburn Buccaneer website points to 'pilot notes' for BuckingEars 
Pilots Notes for Buccaneers (on CD)
http://webbteche.com/Blackburn-Bucca...ost-737682.php
Pilots Notes for Buccaneers (on CD)
http://webbteche.com/Blackburn-Bucca...ost-737682.php
Catapult Launch
When mod. 689 is embodied, provision is made for selecting undercarriage up before the oleos have extended. Pressing a DECK TAKE-OFF button on the port wall, releases the locking solenoid and allows the UP button to be pressed in but does not make the hydraulic selection. The latter is made automatically when the weight comes of the undercarriage legs. A magnetic indicator, adjacent to the push button, shows ON when the button has been pressed and reverts to black when the undercarriage legs have extended on take-off.
WARNING 1: This facility should not be used for take-offs ashore as pressing the button renders the emergency retraction facility (with weight on the undercarriage) in-operative.
WARNING 2: If the button is inadvertently pressed in, the system can only he reset by switching off the battery switch, and the generator switches if both engines are runing.
A standard undercarriage position indicator is adjacent to the push buttons. A warning light on the instrument panel is on when the indicated Mach No. is less than 0-25 and the nose wheel is locked-up; it is fed from the air data computer. When mod. 331 is embodied, a micro switch operated only when the throttle levers are fully OPEN, renders the light inoperative.
When mod. 689 is embodied, provision is made for selecting undercarriage up before the oleos have extended. Pressing a DECK TAKE-OFF button on the port wall, releases the locking solenoid and allows the UP button to be pressed in but does not make the hydraulic selection. The latter is made automatically when the weight comes of the undercarriage legs. A magnetic indicator, adjacent to the push button, shows ON when the button has been pressed and reverts to black when the undercarriage legs have extended on take-off.
WARNING 1: This facility should not be used for take-offs ashore as pressing the button renders the emergency retraction facility (with weight on the undercarriage) in-operative.
WARNING 2: If the button is inadvertently pressed in, the system can only he reset by switching off the battery switch, and the generator switches if both engines are runing.
A standard undercarriage position indicator is adjacent to the push buttons. A warning light on the instrument panel is on when the indicated Mach No. is less than 0-25 and the nose wheel is locked-up; it is fed from the air data computer. When mod. 331 is embodied, a micro switch operated only when the throttle levers are fully OPEN, renders the light inoperative.
Last edited by syncro_single; 19th Aug 2017 at 08:02.
Does anyone remember XN630 at Biggin Hill in July (I think) 1969?
Seem to remember a rumour that the u/c up button was pressed before the take-off roll was commenced, and u/c 'up' would occur when the weight came off the u/c.
In this case all went to plan except the JP decided that it was not yet ready to fly and sat back down on the ground!
Seem to remember a rumour that the u/c up button was pressed before the take-off roll was commenced, and u/c 'up' would occur when the weight came off the u/c.
In this case all went to plan except the JP decided that it was not yet ready to fly and sat back down on the ground!
I believe that pressure was applied to the U/C up button but because of the circuit protection it couldn't be fully pressed in until the weight off wheels micro switches operated. Therefore as soon as the jet was off the deck the button would be fully depressed and the wheels up. Never got confirmation from the aircrew that this was an adopted practice but that was our assumption.
From the pilot's notes:
''Pressing a DECK TAKE-OFF button on the cockpit port wall releases the locking solenoid and allows the UP button to be pressed in, but does not make the hydraulic selection. The latter is made automatically when the weight is removed from the undercarriage legs''
You would usually do this after the aircraft had been tensioned on the cat.
Sorry. Only just read syncro single's reply. Old age...
''Pressing a DECK TAKE-OFF button on the cockpit port wall releases the locking solenoid and allows the UP button to be pressed in, but does not make the hydraulic selection. The latter is made automatically when the weight is removed from the undercarriage legs''
You would usually do this after the aircraft had been tensioned on the cat.
Sorry. Only just read syncro single's reply. Old age...
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Many thanks to all for the replies and information.
From another source I've been advised that Mod. 1530 deleted the switch and this was applicable to all S2b and S2c. At some point a technical instruction was issued to wire lock the guard on the button to prevent its use. Hence most RAF pilots/ground crew might be unaware of it, maybe except those flying S2a's with a pair of side cutters.
I've also looked through quite a few videos and pictures of cat launches and so far have only found one which shows a rapid undercarriage retraction so I guess, as correctly stated above it was only used occasionally. What combination of hot, heavy and low wind over the deck was it intended for?
From another source I've been advised that Mod. 1530 deleted the switch and this was applicable to all S2b and S2c. At some point a technical instruction was issued to wire lock the guard on the button to prevent its use. Hence most RAF pilots/ground crew might be unaware of it, maybe except those flying S2a's with a pair of side cutters.
I've also looked through quite a few videos and pictures of cat launches and so far have only found one which shows a rapid undercarriage retraction so I guess, as correctly stated above it was only used occasionally. What combination of hot, heavy and low wind over the deck was it intended for?
Schiller is correct on both counts, as I would expect.
When the subject of actually using the ‘deck take-off button’ was discussed (in terms of 801 Squadron Mk 1 SOPs in 1962-63) I think it was generally agreed that while no-one doubted that it would work as advertised, no-one wanted to be the first to achieve a catapulted belly take-off. There was a healthy reluctance to press the U/C up button for any other routine purpose than to raise the U/C immediately – in flight. In home waters there seemed to be little performance advantage. I do not recollect the subject being discussed again, even when severely performance limited during potentially hostile tropical operations. Whether anyone ever used the system ‘privately’ (outside of test flying) I do not know.
IIRC, the Mk 1 minimum acceptable ‘acceleration after launch’ was 1 kt per sec – you loaded it up (or unloaded it) til the graph gave you that figure. Considering you came off the end at 50 ft/130 kts and the single engine safety conditions were 200 ft/150kts, there was an interesting performance lacuna. You could see why ‘automatic’ quick retraction was desirable.
By comparison, I was told the Mk 2 roared away at 7 kt per sec. Whereby hangs a different tale of technical woe.
LFH
......................................
When the subject of actually using the ‘deck take-off button’ was discussed (in terms of 801 Squadron Mk 1 SOPs in 1962-63) I think it was generally agreed that while no-one doubted that it would work as advertised, no-one wanted to be the first to achieve a catapulted belly take-off. There was a healthy reluctance to press the U/C up button for any other routine purpose than to raise the U/C immediately – in flight. In home waters there seemed to be little performance advantage. I do not recollect the subject being discussed again, even when severely performance limited during potentially hostile tropical operations. Whether anyone ever used the system ‘privately’ (outside of test flying) I do not know.
What combination of hot, heavy and low wind over the deck was it intended for?
By comparison, I was told the Mk 2 roared away at 7 kt per sec. Whereby hangs a different tale of technical woe.
LFH
......................................
I've also looked through quite a few videos and pictures of cat launches and so far have only found one which shows a rapid undercarriage retraction so I guess, as correctly stated above it was only used occasionally.
Possibly from the Victorious around '66?
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Thanks again everyone for information.
So far after viewing a good few cat launches;- I have 1 photo of a undercarriage clearly part retracted a couple fuselage lengths off the cat and film of a pitch up accident which includes a rapid U/C retraction, just off the cat. The Buccaneer accident records seem to show 3 pitch up crashes, thankfully none fatal, one S1 and two S2's. The film I've found is an S1 but from memory I'm sure I've seen the sequence referred to above, which was test pilot Dave Eagles investigation into the first S2 accident(the ejection seats separation is very different). From Dave's autobiography he records the cause of the uncommanded pitch ups as an unnoticed inconsistency in the setting of the rear horizontal stabiliser between test and squadron aircraft. Does anyone know where this film is on the net?
Now on to RAF Buccaneers;- there's plenty of clips of take off with a very quick U/C retraction. Although a few of these are S2a with the switch albeit inhibit with locking wire, many are not. This again confirms the above comment that quite a few pilots took off, maybe with a finger preloading the U/C up button so retraction would commence as soon as the button solenoid interlock was removed by the weight off wheels micro switch. Or at least pushed the button just as they considered the wheels where just off the asphalt. A comment was made about this leading to a damaged A/C but this doesn't show up in the accident record I've seen;- has anyone got details (the Biggin Hill aircraft was a JP)
So a slightly unexpected conclusion;- the FAA had the function but rarely, if ever used it, whereas the RAF generally didn't have it but seemed keen to emulate it.
So far after viewing a good few cat launches;- I have 1 photo of a undercarriage clearly part retracted a couple fuselage lengths off the cat and film of a pitch up accident which includes a rapid U/C retraction, just off the cat. The Buccaneer accident records seem to show 3 pitch up crashes, thankfully none fatal, one S1 and two S2's. The film I've found is an S1 but from memory I'm sure I've seen the sequence referred to above, which was test pilot Dave Eagles investigation into the first S2 accident(the ejection seats separation is very different). From Dave's autobiography he records the cause of the uncommanded pitch ups as an unnoticed inconsistency in the setting of the rear horizontal stabiliser between test and squadron aircraft. Does anyone know where this film is on the net?
Now on to RAF Buccaneers;- there's plenty of clips of take off with a very quick U/C retraction. Although a few of these are S2a with the switch albeit inhibit with locking wire, many are not. This again confirms the above comment that quite a few pilots took off, maybe with a finger preloading the U/C up button so retraction would commence as soon as the button solenoid interlock was removed by the weight off wheels micro switch. Or at least pushed the button just as they considered the wheels where just off the asphalt. A comment was made about this leading to a damaged A/C but this doesn't show up in the accident record I've seen;- has anyone got details (the Biggin Hill aircraft was a JP)
So a slightly unexpected conclusion;- the FAA had the function but rarely, if ever used it, whereas the RAF generally didn't have it but seemed keen to emulate it.
From what I can recall from my brief struggles with the beast, it was necessary to raise the gear pretty quickly after becoming airborne, because the aircraft accelerated very rapidly towards landing gear limiting speed.
The maximum speed for raising and lowering the landing gear was actually increased from 225 KIAS to 240 KIAS sometime in the early to mid 1980s. The land based take-off technique was to rotate to raise the nosewheel clear of the runway 10 kts before a positive aft stick input was made to unstick. In the normal RAF training configurations (CBLS or ECM pod on outboard wing pylons, underwing tanks or CBLS on the inboard stations, or other relatively low weight stores such as Pavespike or MARTEL data link pod) the take-off speeds with 15-10-10 'flap and droop' were 155/165 KIAS with internal fuel (12 324 lbs), 162/172 KIAS with internal plus bomb door tank fuel (16 080 lbs), 169/179 KIAS with internal plus bomb door plus underwing tank fuel (19 800lbs). Pitch control during the take-off was very good so at unstick speed you could ease the stick back such that the main leg oleos extended progressively and light pressure on the gear 'UP' button was all that was needed to push it in immediately that the oleos reached full extension. You there was no pitch trim change going from 15-10-10 to 0-0-0 so you could then hold the aircraft level and low while you accelerated. Why did we (I!) do it? Because it was great fun and looked spectacular. Where there ever any accidents because of it? Not that I am aware. Did we get bo*****ed for doing it? Frequently. Did it stop us doing it? NO!
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towards us getting faster and closer. We were worried that there was a problem as it seemed firmly stuck to the deck but as it drew level we could see that the gear was up and it was sitting about 3 ft off the runway. Very impressive.
