Torque

[Harry Basset]

I hope some member will be able to enlighten me about the handling of the Seafire Mk 47 in FS9.
I have read that Griffon powered Spitfires and Seafires gave their pilots problems with torque reaction, particularly a fearsome swing on take off. To counteract torque reaction in flight I understand the aircraft were rigged with offset fins and wing incidences. The main book about Seafires said that the Mk 47 with its contra props was able to be built or rigged with basically truly aligned wings and tail as the torque effects were cancelled out by the contra prop. My interpretation of this statement was that on take off the Mk 47 would run straight down the runway (If into wind).
My question is did the contra prop cancel all torque effects or would there have been any effect from the rotating components of the engine?

[PeteP]

Harry, I've forwarded this question to my father-in-law who can probably give you the answer. He was seconded from the RAF to Westlands at Yeovil as a test pilot in 1945 and I know he has every mark of Seafire (and most marks of Spitfire too) in his log book so he should be able to help.
Pete

[PeteP]

Well, I should have checked before I made a statement like, "he has every mark of Seafire ... in his log book". STUPID However, I think his reply, below, still answers your question.
Pete

"Although I did not actually fly a Seafire 47 it was known that the contra props would eliminate the very strong torque to the right found in earlier Mk 21 and 22 Spitfires. The Seafire XVII had a perfectly manageable torque and had no special rigging."

[SkippyBing]

As an aside, I doubt there would enough of a rotating mass in a V like a Griffon to give torque effects. The pistons should cancel each other out which only leaves the crank shaft which has a limited moment arm and may again be self cancelling.
I think as you have two props rotating in opposite directions it should be possible to rig them to cancel any torque, i.e. have the counter-clockwise prop generate a bit more torque to overcome any that is generated by the engine. Bearing in mind the front prop may have to be bigger than the aft one to avoid tip vortices issues this would probably have to be done anyway (it is on boats, but water's much denser so I'm not sure if it's a direct read across).

[cstorey]

I think skippybing is confusing gyroscopic effects here with torque effects. The problem with torque from a single propeller is that whilst the propeller rotates in one direction, the aeroplane tends to rotate in the opposite direction. On the ground this has the effect of digging one wheel in , about which the a/c tends to pivot. The next problem from a single prop is that the slipstream rotates in a spiral in the same direction as the prop rotates, and thus when it reacehes the fin tends to push the fin away from its direction of rotation, again causing a tendency to swing . The third major problem of a single prop is the gyroscopic force it creates. This is particularly a problem on tailwheel a/c, because as the tail is lifted , the gyro force again operates at 90 degrees to the direction in which the plane of the prop is altered. This is rather hard to describe without a diagram, but raising the tail effectively pushes the plane of the prop forwards, and with a left hand rotation, this will cause a swing to the right, and vice versa

These effects are very largely eliminated by contra rotators, leaving only the residual gyroscopic effect of the internal rotating masses, which are small

Incidentally, this was why rotary engined a/c of the WW1 era were so dangerous. The rotating mass was large, with the entire engine rotating round the fixed crankshaft , and so a very large gyro force was created if in particular the nose was suddenly pitched up or down . In the case of a pitch up, with loss of speed bringing the a/c near the stall, the gyro induced swing could easily cause a spin, and with a pitch down, the opposite swing was all too apt to induce what became known as the graveyard spiral

lecture over

Chris

[SkippyBing]

I think you're right!

[Harry Basset]

Good evening everyone

Thank you all for the information. I was basing my comments about rigging of Seafire surfaces to counteract the torque of Griffons based on what I thought I remembered from reading the Seafire book by D Brown published many years ago by Ian Allan. My hazy recollections are that Griffon Seafires were not particularly pleasant to fly, needing constant retrimming, and that the Mk 47 was much improved.
I must try and find a copy that book again.

[bigred1970]

... Incidentally, this was why rotary engined a/c of the WW1 era were so dangerous. The rotating mass was large, with the entire engine rotating round the fixed crankshaft , and so a very large gyro force was created if in particular the nose was suddenly pitched up or down . In the case of a pitch up, with loss of speed bringing the a/c near the stall, the gyro induced swing could easily cause a spin, and with a pitch down, the opposite swing was all too apt to induce what became known as the graveyard spiral

lecture over

Chris

I downloaded a sopwith camel for fs 2004 that has a roatary engine. when you give it full throttle for takoff. (inaqurate I know becase they were always at full throttle) the whole plane tilts to the left and it is fun keeping it in a strait line. I think the mass of the rotary enging is simulated by setting the prop moi artifically high. and I did death spiral it by trying to do a loop to close to the ground to recover from the spin caused by the stall :doho:

[DispatchDragon]

The classic examples of "torque-Roll" were (and still are ) seen with the P51 - there have been many accidents where
either due to having to go around or finding an unacceptable rate of sink on the approach , pilots have tended to firewall
the throttle and go fully coarse with the prop - in a P51 in landing configuration it tends to make the aircraft almost rotate
around the prop - initiating a snap roll - its killed more than few inexperienced pilots

Leif

[Kevin]

Here's a data point on the Spitfire XXII.

My Dad has a few hundred hours on them with 613 (City of Manchester) Sqn. He tells me that they used no more than +8 lb of boost on takeoff, with FULL rudder trim to counteract the torque - with any more boost the aeroplane simply could not be kept straight with rudder.

On one occasion, he was taking off in echelon with the CO when he experienced a prop failure just as they got airborne - it went fully coarse pitch. With full opposite rudder and aileron very quickly applied, the aircraft was only just controllable - it wasn't possible to keep it straight and it slewed across the airfield at Ringway, fortunately away from the other Spitfire. He staggered round the circuit and brought it back in.

As Leif indicates, the torque of these late-generation piston-engined fighters was not to be treated lightly.

Kevin