Buccaneer Flying Qualities
Superb model sir !
Absolutely fantastic. Although even to my eye the fin and tailplane do look a bit small - not your model, I mean the donor aircraft.
We were taught navigation on our ATPLs by a former Buccaneer navigator. He was a human computer - he could do complex nav maths in his head that would take us rookies 20 mins to do using tables and calculators. Amazing.
Could someone briefly explain the tailplane flaps. What were they, why were they needed and why not design the tailplane to move over a greater range?
Absolutely fantastic. Although even to my eye the fin and tailplane do look a bit small - not your model, I mean the donor aircraft.
We were taught navigation on our ATPLs by a former Buccaneer navigator. He was a human computer - he could do complex nav maths in his head that would take us rookies 20 mins to do using tables and calculators. Amazing.
Could someone briefly explain the tailplane flaps. What were they, why were they needed and why not design the tailplane to move over a greater range?
Could someone briefly explain the tailplane flaps. What were they, why were they needed and why not design the tailplane to move over a greater range?
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Deployment of mainplane flaps and drooped ailerons alone would cause a significant n-d pitching moment. To counter this and avoid the need for significant retrimming of the varialble incidence tailplane by the pilot, simultaneous upward extension of a tailplane flap provides an equal and opposite n-u pitching moment. The pilot does not need to make significant control column movements during flap extension and only needs to retrim with IAS change as normal.
If a blown configuration was selected, the tailplane flap would also be blown. The pilot would need to check all 3 blow gauges; the mainplane blow gauges were reasonably well sited, but the tailplane blow gauges was down by the pilot's left elbow. Not much fun at night after a formation VRIAB!
Ergonomics and the Buccaneer cockpit weren't exactly bedfellows!
Ergonomics and the Buccaneer cockpit weren't exactly bedfellows!
Another interesting feature of the tailplane flaps was that they were warped by stops at the tip and the actuator, so they fed in gradually from the inboard to outboard as they were raised.
40 years since Q.....
Cheers!
Thank you BEagle and others 
Airbus FBW does a similar thing, but electronically.
.
Airbus FBW does a similar thing, but electronically.
.
Last edited by Uplinker; 14th Sep 2023 at 09:18. Reason: typo
The actual tailplane flap wasn't blown, it was the lower leading edge of the tailplane.
Another interesting feature of the tailplane flaps was that they were warped by stops at the tip and the actuator, so they fed in gradually from the inboard to outboard as they were raised.
40 years since Q.....
Cheers!
Another interesting feature of the tailplane flaps was that they were warped by stops at the tip and the actuator, so they fed in gradually from the inboard to outboard as they were raised.
40 years since Q.....
Cheers!
That photo is perhaps more interesting what it looks like is parked next to the Bucc.......pretty sure that's a Scimitar, and thus likely one of the last times one was on display, as some were retained for use by FRU up to December 1970 when the final flight of a Scimitar took place.
View of an 800B Scimitar from a Bucc. cockpit during refuelling.
Screenshot from IWM collection item 'Buccaneers' of 1966 (Narrated by the late Bob Holness) https://www.iwm.org.uk/collections/i...ect/1060020488
But two can play at that game
or even 4
Last edited by SLXOwft; 14th Sep 2023 at 17:33.
That photo is perhaps more interesting what it looks like is parked next to the Bucc.......pretty sure that's a Scimitar, and thus likely one of the last times one was on display, as some were retained for use by FRU up to December 1970 when the final flight of a Scimitar took place.
https://www.airliners.net/photo/UK-N...r-F1/1651584/L
https://upload.wikimedia.org/wikiped...kemble_arp.jpg
I was beginning to get worried - I was at Lossie that day (I'm just out of shot on the left
), and I'm sure I would have noticed a Scimitar had there been one on show.The Sea Vixen between the Ark Buccaneer and the Brawdy Gannet was an 899 NAS example from Eagle (one of two there on the day, can't say which one).
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I bow to better knowledge and eyewitness evidence ... plus there is no wing fence which I should have spotted. I plead being in short trousers (and not tropical kit ones) at the time. Anyway back to Buccaneers.
Gnome de PPRuNe
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<br /><br />I was taught that the relationships between the characteristics [flight, or sailing or whatever] of the real size object and the scaled down version involve some very fancy maths [math if preferred] and a great deal of suck it and see experimentation.<br /><br />The days of film comical sea and air battles using models are long gone now we have CGI and AI, but the real world behaviour relationships are fraught with Bernoullies, vortices, turbulence and Gremlins.
Last edited by langleybaston; 14th Sep 2023 at 18:58. Reason: speeling
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JSF-TC great work - really nicely done. I'm enjoying reading your build thread. I had a thought about the blowing - had you thought about using electric ducted fans and some careful duct design to blow air?
Edit: Have now completely read the build thread and have to say I think that there is still room for investigation in your hstab servo calcs, however you are watching the servo current, so, it can't run away from you. If you were feeling brave I suggest do some high altitude runs at approach speed to look at where the stab runs out of power with deflected flap angle.
I would be looking to calculate the centre of lift of the stab plane with and without stab flap deflection to make sure you are using the longest moment arm for your servo torque calc - catching the deflected distance change is good, but might be only one side of the story.
The deflected stab flap will reduce your stab plane stall angle as a flap would on a mainplane. The initial guess with this is to draw a line between LE and TE - the angle that line makes with the stab chordline will give you an effective stab plane operating angle of attack.
The other thing I would look at is whether your servo actuator rod is stiff enough not to bow out under combined load of the servo and the stab pressure load - this would not necessarily increase servo load (hence not seeing the servo current go up) but also reducing the effectiveness of your hstab (because its at a lower deflection angle than you think). I can't see what your stab actuator rod geometry is.
I do a lot with the UAV world in and out of professional life and it is interesting to see the differences in minimum requirements - for example all control surfaces should really have redundant actuation. Telemetry and monitoring is also another difference between my RC buddies and my UAV buddies (I sit in both camps!) My Cube Black, HERE GPS and Mauch power electronics collect masses of data for me, all in one place. I know you have some of that data with the JETI system, but there is another level you could go to - and you could use the CUBE Black as pass through or as a basic gyro (FBWA mode), up to and including full automatic mission from take off to landing. I know one F3A pilot that uses an ardupilot flight controller and GPS just to log his flights for review.
Anyway, just some comments!
Edit: Have now completely read the build thread and have to say I think that there is still room for investigation in your hstab servo calcs, however you are watching the servo current, so, it can't run away from you. If you were feeling brave I suggest do some high altitude runs at approach speed to look at where the stab runs out of power with deflected flap angle.
I would be looking to calculate the centre of lift of the stab plane with and without stab flap deflection to make sure you are using the longest moment arm for your servo torque calc - catching the deflected distance change is good, but might be only one side of the story.
The deflected stab flap will reduce your stab plane stall angle as a flap would on a mainplane. The initial guess with this is to draw a line between LE and TE - the angle that line makes with the stab chordline will give you an effective stab plane operating angle of attack.
The other thing I would look at is whether your servo actuator rod is stiff enough not to bow out under combined load of the servo and the stab pressure load - this would not necessarily increase servo load (hence not seeing the servo current go up) but also reducing the effectiveness of your hstab (because its at a lower deflection angle than you think). I can't see what your stab actuator rod geometry is.
I do a lot with the UAV world in and out of professional life and it is interesting to see the differences in minimum requirements - for example all control surfaces should really have redundant actuation. Telemetry and monitoring is also another difference between my RC buddies and my UAV buddies (I sit in both camps!) My Cube Black, HERE GPS and Mauch power electronics collect masses of data for me, all in one place. I know you have some of that data with the JETI system, but there is another level you could go to - and you could use the CUBE Black as pass through or as a basic gyro (FBWA mode), up to and including full automatic mission from take off to landing. I know one F3A pilot that uses an ardupilot flight controller and GPS just to log his flights for review.
Anyway, just some comments!
Last edited by unmanned_droid; 15th Sep 2023 at 16:28.
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To the left as one looks is the shadow cast by an F-4 and beyond the Scimitar Sea Vixen what looks like the tail of a Gannet
View of an 800B Scimitar from a Bucc. cockpit during refuelling.
Screenshot from IWM collection item 'Buccaneers' of 1966 (Narrated by the late Bob Holness) https://www.iwm.org.uk/collections/i...ect/1060020488
But two can play at that game
or even 4
View of an 800B Scimitar from a Bucc. cockpit during refuelling.
Screenshot from IWM collection item 'Buccaneers' of 1966 (Narrated by the late Bob Holness) https://www.iwm.org.uk/collections/i...ect/1060020488
But two can play at that game
or even 4
Last edited by SpazSinbad; 15th Sep 2023 at 12:21.
In particular, when the flaps and ailerons are drooped for landing, the model exhibits a very strong tendency to roll wings level when centering the stick and has the need to hold in significant proverse aileron all the way through the turn. This has taken some effort to balance control throws and to learn the characteristic as it was so unusual compared to everything else I've flown.
Awesome model, very well done! General question about scale modelling: We all know that you don't normally scale things directly because of cube/square laws, which is why elephants have proportionately fatter legs than cats. What challenges does this pose for scale modelling? Do you fly at a lower wing loading than the real thing? Are you helped or hindered by the fact you're flying more slowly?
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