Camel torque..conclusive evidence

Calling Darryl,Michael!!I checked my copy of 'Winged Victory'by V.M.Yeates(who was a 5-victory ace on Camels).By the way,the book is truly a collector's item(Granada Publishing Ltd.Last published 1974 by Mayflower Books Ltd,Frogmore,St.Albans,Herts AL2 2NF).Yeates clears up the confusion in(the qouting of?? Arthur Gould Lee)in'In the Cockpit'(right rudder on takeoff to correct swing followed by left rudder in the air).He says,in page30/31 of his book"Baker,his instructor,had given him a preliminary lecture.'I suppose you haven't run a Clerget engine before.You'll find it just like a Le Rhone...Keep just a shade of LEFT rudder on to counteract the twist to the RIGHT..remember to use the rudder as little as possible,you hardly want any when you want to turn'".He also says that the Camel was terrifically tail-heavy!!And yes,I too have noticed that the photographs appear to show that the prop turned clockwise,and I can't explain it...a rotary engine would create torque in the same way as a stationary engine..make the aeroplane swing in the direction opposite to the direction of the prop.But at least poor old Yeates has cleared the confusion of how the torque could be different on the ground and in the air...it wasn't!!!By the way,please note that he says that the Clerget and the Le Rhone were similar in behaviour.Sorry I didn't call you guys earlier..I was on holiday.Regards.Mukund.

I can explane why the photo makes the prop appear to turn opposite of the way it actualy turns, some lighting conditions will cause a strobe effect when sean through a spining object try looking down at a bike wheel with the only light is a street light. The poor lighting contitions and the low shutter speed of a WWI era camera most likely causes the prop to appear to spin that way. Im sorry I haven't seen the Photo you refer to but in all of the pictures ive seen I can't reamember being able to tell which way the props were turning. Why make a big deal over a photo if you have experts saying It turns the other way?

Hi,Phil.The photographs we were referring to showed the props curved(with the engine stopped)such that they would turn to the right thus implying that the aeroplane would swing left which,in fact,was not the case with the Camel which used to swing to the right.This is the confusing thing because a rotary engine and a stationary one would behave in the the same way(except,of course,that in the case of a rotary engine,the engine itself turns with the prop).By the way,Michael,I double-checked on the direction of torque for rotary engines and stationary engines from an engineer friend--he confirms that they are the same.But the shape of the prop on SOME photographs is STILL confusing!!!Cheers.Mukund.

How could the Camel be tail-heavy? Didn't it have an exceptionally short fuselage? What was back there?

RK

Tail heaviness can be due to the distance from the horizontal tail aerodynamic center to the aircraft center of gravity relative to the distance from the wing aerodynamic center to the aircraft center of gravity. If the horizontal tail arm is short then the tail must provide more force to effect a pitch up or pitch down than the same size tail with a longer distance. The aircraft needs more tail size or a longer fuselage that gices a longer arm.

V/R
Paul

I believe the Camel was deliberately rigged tail-heavy, probably as a response to the concentration of mass in the first few feet of the forward fuselage.

I admit to being confused about this whole torque thing. But if the photos imply that the prop spins to the right, and my engineering friends at DeHavilland tell me that a rotary would have to spin to the right in order to give the Camel that right-hand pull, then I will continue to believe that the Clerget and Bentley Camels had engines that turned to the right. (Or at least I'll continue to believe that until I talk to someone with direct experience with one of these engines...)

Hi,Ray.I thought somebody would ask,considering the fact that most of the arguments so far have talked about how all of the Camel's weight was in the front!!I quote from page 30 of 'Winged Victory'."Flying Camels was not everyone's work.they were by far the most difficult of service machines to handle.Many pilots killed themselves by crashing in a right-hand spin when they were learning to fly them.A Camel hated an inexperienced hand and flopped into a frantic spin at the least opportunity.They were unlike ordinary aeroplanes,being quite unstable,IMMODERATELY TAIL-HEAVY,so light at the controls that the slightest jerk or inaccuracy would them all over the sky,difficult to land,deadly to crash:a list of vices to emasculate the stoutest courage,and the first flight in a Camel was always a terrible ordeal.They were bringing out a two-seater training Camel for dual work,in the hope of reducing that thirty per cent of crashes on the first solo flights."You're quite right.there was very little of WEIGHT distribution behind the pilot and the aeroplane was probably RIGGED tail-heavy.Regards.Mukund.

Hi,Mike.Could you get your De Havilland engineer friend to e-mail me explaining how a right-hand turning rotary would pull the aeroplane to the right and not to the left?If my understanding is at fault,I would most certainly like to know where I've gone wrong.Just a short technical(the more technical,the better)note will do.You have my e-mail address.Regards.Mukund.

[Darryl]

Hello Mukund,

Conclusive evidence!!! Horsefeathers!!!!!*G*

With the greatest respect, you have merely chosen another quote from a WW1 airman, no more valid than A G Lee's.

The quote you have chosen seems to me to be in a style which strongly suggests that it is written with an assumption of various facts of which a pilot would be aware. For example, in my opinion (because it talks next about turns), the comment about left rudder refers to level flight. (I said all along left rudder for that.) Arthur Gould Lee (quoted in the book "In the Cockpit" from the book "No Parachute")
*specifically* talks about level flight and takeoff. A pilot will usually assume that anyone interested in flying will know about P factor and won't specifically mention right rudder to take off. This is what is going on in your quote, in my opinion. But AG Lee does specifically mention it, making his quote more useful to the layman.

Now, as to the physics of the thing. The engines (Le Rhone, Clerget and Bentley) all spin to the right. The torque force is also to the right and I beleive I have twigged to the reason.

Can we assume for a moment that both a stationary and rotary turn a prop to the right. The inline exerts force on a crankshaft to turn it to the right. The torque created rocks the engine to the left as you have indicated.. Propellor torque also acts to the left.
Now take the rotary. Force is exerted by the engine on the central shaft but this time the whole engine spins to the right and you may think that a LEFT torque would be created thus meaning the Camels engine would have to turn LEFT to give RIGHT torque.** BUT** fix the engine mass and let the whole plane spin and you will find that it has a RIGHT to LEFT rotation. Voila, you have a RIGHT torque effect exactly corresponding with the stationary engine!!!!!!! The difference being made by the fact that the WHOLE engine spins and therefore the point of reference is different!!!
Your engineer friend was, I suspect, thinking of a *modern* rotary engine where a *significant* part of the engine mass spins WITH the crankshaft, inside a casing. This would, of course, give a left torque. But it is not the same as the rotary we are talking (torquing??) about.

Now as to right rudder for take off. The P factor means a swirling slipstream striking the left fuelage and tail and pushing the plane left. At slow forward speed with a huge prop and the leverage gained because the tail goes aft quite a way and the mass of the aircraft (in the Camel's case) is centered on or very near the CG, this effect would be severe, severe enough, on the evidence I have, to overcome the gyro to the right until flying speed has been attained.

I hope DeHavilland's engineer comes up with a similar (if some what less hamfisted) explaination to the torque question.

Very best regards (sorry for boring everyone)

Darryl

[Vigilant]

Darryl,

Run that one by me again....Sounds like you have a good insight into this, but I'm afraid I don't follow. You say the Camel would rotate right to left if the engine were held stationary. OK. But is that not left torque? -- i.e. the plane will want to turn left. It seems to me the only relevant difference between rotary and stationary engines is that in the latter a much smaller mass of metal is moving thereby imparting a similarly smaller torque reaction to the airframe.
But I'm probably being dense. Please tell me where I'm going wrong!

Yours,

Vigilant.