More Camel torque please

[Ack-Ack]

The video only proves one thing - my r/c skills are average at best. But I can attest to the fact that this model, which has the motor well forward of the CG, can turn 180 degrees to the right in very short order. Left turns however are much more sedate.

Basically, you're using the torque to roll into your turns.  Since the torque is to the right, you're plane is going to roll in that direction faster than it would be if you fought against the torque and rolled to the left in the turn.  The torque itself isn't providing the forces to turn the plane, it's just rolling it to one side.

ack-ack

[Baumer]

Any topic that can combine gang signs,

 

and differential equations,



has to be considered and excellent discussion.   

I haven't done this much reading/research and math in a long time.

[SCTusk]

lol enjoyed that 

Basically, you're using the torque to roll into your turns.  Since the torque is to the right, you're plane is going to roll in that direction faster than it would be if you fought against the torque and rolled to the left in the turn.  The torque itself isn't providing the forces to turn the plane, it's just rolling it to one side.

ack-ack

I think there's some confusion regarding the use of the term 'torque' here, which is why I changed tack from my original post and tried to refer to it as a force; although HiTech says it's actually a torque, so I'm happy to call it such. Problem is we now have two 'torques', the first is the usual torque of the motor, while the second is the gyroscopic effect as discussed, which manifests itself in a perpendicular direction to the axis of rotation, 90 degrees offset to the applied force (the force which is applied to the spinning motor as the aircraft turns).

As HiTech was quick to discover, my knowledge of vectors and this type of maths is limited to some barely remembered head scratching in final year physics a very long time ago. So I'm content to leave that side of it to those more familiar with it. I'm more concerned with the initial 'hands on' awareness of the concept, and observable (and repeatable) real world results which might either confirm or refute the anecdotal evidence. Here's a link to a fun and informative video on gyroscopes:

http://www.youtube.com/watch?v=cquvA_IpEsA

As the video shows, there is an effect at work which seems capable of moving the spinning mass in a way which could cause the effects suggested by the pilot reports, with the second question being if so, to what degree? Unfortunately I have been unable to discover much about the effect in AH. I am simply assured that it is modelled. There seems to be some evidence of the effect (in the turn) but I would have expected it to be more pronounced (based on personal experience and the anecdotal evidence).

Reading through the thread again it seems that I should have made it clear from the outset, I would certainly not want any change made to the Camel FM if the evidence suggests otherwise.

But it would appear that unless you hold a degree in Physics you are not encouraged to participate in such a discussion here. I am not aware of any scientific endeavor where a general 'real world' or 'hands on' understanding of the material is not encouraged, usually prior to the technical details being considered.

I have the highest regard for HiTech and his team for producing an extremely convincing simulation. I would not want anything changed unless there was conclusive - or as near conclusive as could be obtained - evidence to justify such change. The evidence of my own eyes and hands convinces me, but perhaps I suffer from the confusion of the layman. Someone tell me then, in simple lay terms, why does the gyroscope defy gravity in the video? And why would the 'force' or 'torque' (call it what you will) not impact on the flight characteristics of the Sopwith Camel?

 

[hitech]

The force you are missing is the force from the table transmitted via the little black stand. In essence the gyro is changing the down force of gravity combined with an up force up force of the stand (creating a torque ) to a torque  90 deg to the fly wheel.This torque in the 90 deg rotation is then trying to rotate the gyro about its center of mass. Since the one end is fixed horizontally the rotation is resisted by a force from the stand and hence the net force roates around the stand.


This is very similar to what I have said in the beginning , only in this case the force we a speaking of is not trying to rotate the gyro down like gravity, but rather we are trying to rotate it horizontally and the gyro is trying to change the rotation to the vertical plane hence either lifting or lowing the nose. But you are still thinking of turns as rotation, instead of changes in direction like the stone in the video.

But it would appear that unless you hold a degree in Physics you are not encouraged to participate in such a discussion here. I am not aware of any scientific endeavor where a general 'real world' or 'hands on' understanding of the material is not encouraged, usually prior to the technical details being considered.

This is pure bs, but if you wish to discuss a matter and try to argue basic physics, we would expect you to at least attempt to  learn the subject matter being discussed and possibly except what people who do study this stuff generally know what they are speaking of.

I think there's some confusion regarding the use of the term 'torque' here, which is why I changed tack from my original post and tried to refer to it as a force; although HiTech says it's actually a torque, so I'm happy to call it such. Problem is we now have two 'torques', the first is the usual torque of the motor

You do not just have 2 torques you have the sum of many in which the total is described as 3 terms, each a torque about an axis, or in airplane terms roll pitch and yaw.

As the video shows, there is an effect at work which seems capable of moving the spinning mass in a way which could cause the effects suggested by the pilot reports, with the second question being if so, to what degree? Unfortunately I have been unable to discover much about the effect in AH. I am simply assured that it is modeled. There seems to be some evidence of the effect (in the turn) but I would have expected it to be more pronounced (based on personal experience and the anecdotal evidence).

And this is where you start to get your self into trouble. The net effect of the gyro scope really comes down to 3 numbers. RPM of prop, Moment of inertia of the prop, moment of inertia of the plane. I have documents showing these numbers, and hence unless the documents are wrong (doubt full) or we typeoed the number, the effect would be correct.

Unfortunately I have been unable to discover much about the effect in AH.

What exactly is it you wish to discover about the effect? I don't believe you have even asked anything about the effect in AH. And other then the exact numbers, (which I do not believe would help you anyway). The effects are simple and can be verified, yaw left nose pitches up, yaw right, nose pitches down. Pitch up plane will yaw right, pitch down plane will yaw left.


HiTech

[SCTusk]

RPM of prop, Moment of inertia of the prop, moment of inertia of the plane.
HiTech

I presume you mean moment of inertia of engine? Or are you just modelling the spinning prop?

[Karnak]

In a discussion prior to the release of the WWI planes HTC stated that the gyroscopic effect of the DR.1 and F.1 Camel would be significantly higher due to their rotary engines.  They are modeling the spinning engines.

[hitech]

I presume you mean moment of inertia of engine? Or are you just modelling the spinning prop?

Yes I was including the mass of the engine with the prop.

HiTech

[SCTusk]

What exactly is it you wish to discover about the effect? I don't believe you have even asked anything about the effect in AH. And other then the exact numbers, (which I do not believe would help you anyway). The effects are simple and can be verified, yaw left nose pitches up, yaw right, nose pitches down. Pitch up plane will yaw right, pitch down plane will yaw left.


HiTech

So in a sustained right hand turn (for instance) which requires an element of (a) pitch up plus an element of (b) yaw right, the gyro effects on the aircraft will be (a) yaw right and (b) pitch down?

I'm fairly sure that's what I suggested in the beginning. I ask so that I can be clear on your position because earlier you accused me of talking BS when I suggested that gyroscopic effects could assist the aircraft to turn.

[hitech]

So in a sustained right hand turn (for instance) which requires an element of (a) pitch up plus an element of (b) yaw right, the gyro effects on the aircraft will be (a) yaw right and (b) pitch down?

I'm fairly sure that's what I suggested in the beginning. I ask so that I can be clear on your position because earlier you accused me of talking BS when I suggested that gyroscopic effects could assist the aircraft to turn.

Correct, simply draw a line straight down from the turn circle, how the line passes threw the plane in its banked to the right will be the resultant torque of ( down pitch and right yaw). But note, that is in no way assisting the aircraft turn, it is providing a torque perpendicular to the turn. Just because an aircraft is yawing right in a right turn, does not imply an assist to the turn. The yaw is generally stated in a plane relative direction. So as you can see in the case of a 90 deg bank, you would only have a yaw force and no pitch, but that yaw would not be in the direction of the turn. That yaw is not in the direction of the turn and hence in no way assisting it. And you are still confusing the terms turn which in this context refers to a change in the inertia (a liner direction/translation change) which is created ONLY by lift and thrust,and nothing to do with torque on the plane. The gyro would be capable of rotating the plane, but it would still be flying in a straight line.

As I have been trying to explain, and you seem to not clearly see the difference between rotation and translation forces/torque. It is impossible for a gyro to CREATE a translation force. In your example of the right hand turning plane, the rudder would then be pushed left and up elevator applied to put the plane at max aoa and remove the slip caused by the gyro. The extra control input in both rudder and elevator would cause a very slight increase in drag and in the right had turn create a net force in the down direction. So in the right hand turn just as in the left the gyro works against your right hand turn do to the extra drag created by the controls.




HiTech

[SCTusk]

Thanks HiTech for taking the trouble of phrasing the above in terms I can understand. I trust this thread hasn't tested your patience too much, I expected worse than the occassional reference to 'BS' and consider myself lucky you have confined yourself to that alone. My old flying instructor had the habit more than 30 years ago of kicking my butt sharply from the rear cockpit whenever I was slow to pick something up lol. I like to think his efforts weren't wasted and hopefully yours won't be either. If at the end of the day I appear to not fully understand the concept then perhaps others reading this thread will get something from it.

If I may just revisit the salient points of the discussion on which I think we agree, if I state anything incorrectly please do not hesitate to correct me (I will attempt to use your preferred terminology for clarity, but I will use the term 'gyroscopic effect' rather than 'gyroscopic precession' but meaning the same thing).

btw I'm referring to a gyroscope as I do this so hopefully I'll get it right lol.

1. In consideration of a spinning mass rotating around (e.g.) the X axis. When a torque is applied around the Y axis a gyroscopic effect or torque is produced around the Z axis. Similarly when a torque is applied around the Z axis a gyroscopic torque is produced around the Y axis.

2. In the absence of additional torque or resistance this reactive gyroscopic torque will cause the spinning mass to rotate around either the Y or Z axis as indicated above. 

3. The power of the reactive torque is directly related to the mass, the rate of revolution of the mass, and the power of the initiating torque.

4. The reactive torque is instantaneous to the initiating torque.

5. It follows that in a clockwise (viewed from behind) rotary engine aircraft a pitch up movement will create a yaw to the right, a pitch down movement will create a yaw to the left, a yaw to the right will create a pitch down and a yaw to the left will create a pitch up.

6. It further follows that in a right hand 45 degree banked co-ordinated turn (e.g.) the aircraft will require some degree of left yaw and pitch up input to achieve a co-ordinated or 'balanced' flat turn.

As I said, if there are any anomolies in the previous statements please respond accordingly. In the meantime I will assume we are in accordance on these significant points. I don't think there's anything here so far that runs contrary to my own initial assumptions (other than terminology) so if you are happy with it I presume we have been more or less 'on the same page' at least in regard to these basic principles.   

I have something further to add but prefer to get these points clarified before proceeding.

[hitech]

SCTusk:

I don't see anything I disagree with other then some very minor term stuff.

HiTech

[Angus]

Being a tad lazy, - I have a simple question, which may have been answered somewhere in the debate.
Would there be any difference between the effect of a rotary engine and another sort apart from the rotary being able to "snap" the aircraft faster into one direction?
Just me maybe,,,,but I have to fix washing mashines all the time, and there is a reason while the lid is supposed to be locked....

[Mano]

there is a reason while the lid is supposed to be locked....

.
.....to keep out little fingers.

[uptown]

Every time I try and read this thread I find myself dreaming of camel toes and quickly lose interest in airplanes.

[Ghosth]

Angus There are many differences between the different planes, esp between WWI and WWII.

However, even a 109g2 rolls considerably faster to the right than the left.
In effect to roll left you either roll slow, or cut the throttle to reduce the torque.

All you need is a stop watch, and a repeatable flight pattern. Ie same plane, same alt, same airspeed, etc.