More Camel torque please

[Wmaker]

Ok Wmaker if you own a gyroscope feel free to try this, if not I guess you'll just have to take my word for it. Spin the mass and hold the device arm outstretched such that the mass is turning clockwise from your perspective looking at it from 'behind' (along the axis of rotation). This corresponds to the rotation of the rotary engine in the Camel. Now move your arm stiffly right and left. You should notice some tendency for the device to pull or twist up when going left, and down when going right. This moderate effect known as precession replicates the type of reaction we see in a rotary engine aircraft configured normally, i.e. the engine is way out the front well clear of the centre of gravity, which has been moved rearward by the various other large masses being spread around to create a CG roughly one third the chord back from the leading edge of a wing (pair of wings CG position more complex especially if staggered) situated appropriately further back along the fuselage.

In the case of the Camel however, most of the mass was packed into the nose. The wings were well forward to compensate (bringing the wings to the CG as it were) so much so that the aircraft flew generally 'tail heavy'. So the mass is concentrated close around the CG. To replicate the gyroscopic effects in this situation run the experiment again but this time turn the device right and left using your wrist. You will notice a much more powerful tendency for the device to twist up when going left, and down when going right. Now hold the frame of the device from the side, such that you are looking across the axis of rotation with the left side of the mass moving toward you (i.e. replicating looking down on the Camel from above). Spin up and twist the device clockwise and anticlockwise using your wrist. Notice that the left side of the device pulls or twists down (away from you) when turning the device anti-clockwise, and up (towards you) when turning clockwise.

So the combined effect of the gyroscopic phenomenon in the Camel would have been a tendency to go outside wing high in the turn (which assists in both directions) but nose high in a left turn forcing adverse control input in pitch (stick forward) and extra input in yaw (left rudder) to hold the nose. In a right turn there would have been a requirement for extra pitch input (stick back) and adverse yaw input (left rudder) to hold the nose, but in this case the 'adverse' yaw input is actually a misnomer as it would actually result in simply less right rudder input, and you would generally be wanting the nose to stay down anyway to maintain your speed.

The overall result then is to produce somewhat clumsy turns to the left but rapid turns to the right, and on second thoughts I do believe these would have been sustainable. So long as the motor is still spinning the forces would continue to apply. I doubt very much if hard data existed back in the day (WW1 pilots would have paid scant attention to them anyway), the effect was pronounced enough to have given the Camel a reputation as a dangerous machine for the novice, and induced many of its' pilots to turn right 270 degrees rather than turning left 90 degrees fighting the stick. The Dr1 spinning a lighter mass placed further away from the CG albeit at similar rpm would likely have experienced significantly less of this effect, much like the initial experiment with the gyroscope at arms length, which would explain why the effect seems never to be mentioned in respect of the Dr1 in the available literature.

I'm well aware of the effects you described here and like I said, they are already clearly modelled in AH. I also agree with you that the tendency of turning better to the right is most probably largely caused by the smaller amount of control surface drag than when turning to the left due to the gyroscopic effect of the rotary engine.

Please post data on the weights of the Camel and Dr.I engines and about their location from the CoG. Btw, as far as I know, Dr.I flew tail heavy aswell.

Once more, this is how things are already modelled in AH. Camel turns easier and faster to the right than it does to the left in AH aswell. Therefore, I don't see a problem. If you think it should turn "better" to the right than a Dr.I, then you have to prove it.

When you don't have any data it actually goes like this: "You have to take HTC's word for it." They've put the parameters of these planes into their FM, tweaked some and came up with the flight models we have now. Unless you have some kind of hard reference to compare their model against...well again "You just have to take their word for it."

Here's an interesting paper on WWI fighters: home.comcast.net/~clipper-108/AIAAPaper2005-119.pdf

In the Results and Discussion section it says:

"The data obtained here is intended to
illustrate the development of the fighter and fighter
tactics during WWI. The presented data is not
claimed to be accurate beyond what is required for its
intended purpose."

...So you can take it for what it's worth, but to me, the findings seem logical.

Here's a turn rate table from that paper:



...I'm sure you'll say it can't be anywhere near the truth because of the disclaimer above and since it doesn't fit your agenda.

To me, it seems logical because of the almost identical wingloadings and clearly better lift coefficients of the Dr.I.

[SCTusk]

I'm well aware of the effects you described here and like I said, they are already clearly modelled in AH. I also agree with you that the tendency of turning better to the right is most probably largely caused by the smaller amount of control surface drag than when turning to the left due to the gyroscopic effect of the rotary engine.

At no point did I suggest that control surface drag had any significant role in this phenomena. Your statement clearly demonstrates that you are, in fact, not well aware of the effects I described.

The AIAA paper has some apparently good data and analysis based entirely on aerodynamics alone, only mentioning gyroscopic effect in passing, and only in relation to safe handling. It would appear that the author, like yourself, either chose not to examine the effect or was unaware of its' significance. I found his comments on the relative merits of the two aircraft in question revealing:

"The figures show that the Sopwith Camel and Fokker Dr.1 were fairly evenly matched. They shared similar top speeds and climb and turn rates. However, in climb and speed, the Camel had the slight edge. This may be why the Camel was successful while the Dr.1 was not."

He obviously has no idea why. And so we see the problem with trying to understand the world around us through data alone; everything is so much more complex than the data suggests. Personally I don't trust charts, graphs and stats.... they can be useful but you first need to see the bigger picture.

"Not even the Fokker triplane could follow a camel in a right-handed bank" -Capt Henry Winslow Woollett DSO, MC and Bar - 35 victories

      

[Wmaker]

At no point did I suggest that control surface drag had any significant role in this phenomena. Your statement clearly demonstrates that you are, in fact, not well aware of the effects I described.

Oh, ok. I thought there was something of some logic hidden in here...

The overall result then is to produce somewhat clumsy turns to the left but rapid turns to the right, and on second thoughts I do believe these would have been sustainable. So long as the motor is still spinning the forces would continue to apply.

I read a bit took much into your comments and actually tought you came up with somewhat logical reasoning regaring what causes the better turning to the right. Sorry, my mistake.

I'm well aware of the gyroscopic effects but no, unlike you, I don't think they magically make the Camel a better turner than Dr.I through some unexplainable force.

The AIAA paper has some apparently good data and analysis based entirely on aerodynamics alone, only mentioning gyroscopic effect in passing, and only in relation to safe handling. It would appear that the author, like yourself, either chose not to examine the effect or was unaware of its' significance.

To this, I cannot really say much else than; "whatever".

Please explain the exact mechanics/physics behind your opinion. Why exactly the gyroscopic effects of the Camel make it turn better to the right?

I can't really see any other reason than the plane was generally easier to fly in a right turn than it was in a left turn and the fact that it needed less deflection of various control surfaces in a right turn made it have less drag in a right turn and therefore haveing a smaller turn radius to the right.

I could well be missing something but you certainly haven't given a beliveable explanation why Camel's gyroscopic effects would somehow be more beneficial than Dr.I's in this regard. Considering the forces involved to an aircraft in a steady state sustained turn, I really don't see how this vague "shorter/longer distance of the engine from CoG" would have any effect. Please explain the mechanics through which you think it has an effect?

[Wmaker]

"Not even the Fokker triplane could follow a camel in a right-handed bank" -Capt Henry Winslow Woollett DSO, MC and Bar - 35 victories     

You obviously value anecdotes higher than physics or hard data. You totally ignore things like, differences in pilot skill, individual airframe's condition, perception, etc etc...

[SCTusk]

I read a bit took much into your comments and actually tought you came up with somewhat logical reasoning regaring what causes the better turning to the right. Sorry, my mistake. Smiley

I'm well aware of the gyroscopic effects but no, unlike you, I don't think they magically make the Camel a better turner than Dr.I through some unexplainable force.

The reasoning is valid. Repeatedly claiming it isn't does not change the reality of it. The gyroscopic force is not magic, its' cause is well known and well documented. If you were genuinely well aware of it this aspect of the discussion would be unnecessary.

Please explain the exact mechanics/physics behind your opinion. Why exactly the gyroscopic effects of the Camel make it turn better to the right?

I have already explained all this up to but excluding the cause of the gyroscopic phenomena itself, which is more in the domain of a physics lesson and not something I can effectively accomplish here. If you can get hold of a gyroscope (even a cheap childs toy would suffice) and follow the guide in my earlier post I'm certain that you would realise the significance of the effect 'hands on'. If you prefer a more detailed study, look here: http://www.freestudy.co.uk/dynamics/gyroscope.pdf

Anyone actually familiar with the science but still curious about the modelling in AH may find this interesting. Here's the results of a few quick low speed turn tests in AH WW1 offline; subjective of course, it would help if a number of players would post their own data. Tests were conducted at about 100 feet to minimise deviation in altitude, at a sustainable speed of 80 (mph or knots? gauges not marked). Stall warning buzzer sounding but not urgent. Very little nose up or nose down tendency was evident (rudder trims were centralised from default right-trim setting prior to tests. NB failure to do this could be why some players report nose high in left turns and nose low in right turns).

All results are in seconds. Five turns each way per aircraft, recorded after initial 'settling' turn.

Camel
right turn: 9 10 10 9 10
left turn: 9 10 10 10 10

Dr1
right turn: 9 9 10 10 9
left turn: 9 9 9 9 9

My sticks are set up for the Camel and I am low time on the Dr1 so this may account for my unexpected results with that aircraft. Further testing at moderate and high speeds may also prove illuminating. At this stage (with my stick setup) any gyroscopic effects modelled in the sim appear minimal.

[Wmaker]

The reasoning is valid. Repeatedly claiming it isn't does not change the reality of it. The gyroscopic force is not magic, its' cause is well known and well documented. If you were genuinely well aware of it this aspect of the discussion would be unnecessary.

I have already explained all this up to but excluding the cause of the gyroscopic phenomena itself, which is more in the domain of a physics lesson and not something I can effectively accomplish here. If you can get hold of a gyroscope (even a cheap childs toy would suffice) and follow the guide in my earlier post I'm certain that you would realise the significance of the effect 'hands on'. If you prefer a more detailed study, look here: http://www.freestudy.co.uk/dynamics/gyroscope.pdf

<sigh>

You have explained how a gyroscope works, and that's nothing new. But you haven't explained how it makes the turn performance of the Camel better to the right. And specially, how it makes the Camel with poorer lift coefficient turn better than the Dr.I. The question is simple enough, why don't you answer it?

any gyroscopic effects modelled in the sim appear minimal.

I, on the other hand, find them to be quite noticeable.

[Wmaker]

The funny thing here is that only now you actually start doing some actual testing and then find that the results of your testing don't support your initial perception.

Another question: Would you have started this thread if you had first done this testing and found out that the results don't support you initial beliefs?

[Wmaker]

I'll try to approach this turning issue between Camel and Dr.I strictly from the physics point of view.

So we have two airplanes, Camel and Dr.I. Camel produces 130hp and Dr.I puts out 110ps. Assuming similar prop efficiency, Camel has more thrust at its disposal. These planes also have exactly the same top speed of 115mph at sea level in the game. This indicates that since Dr.I has less thrust it must have less parasite drag aswell. The weights in AH match to the pound the weights mentioned in several sources. And this puts their wingloadings at 6.46lbs/sqft for the Dr.I and 6.30lbs/sqft for the Camel. So the difference in wing loading is ~2.5% for the Camel. In-game testing shows that Camel stalls at 50mph at 1000ft and that Dr.I stalls at 46mph at 1000ft, both at full flying weight. That gives Clmax of 1.02 for the Camel and 1.23 for the Dr.I, a ~20,5% difference. The stall speeds were determined by cutting the engine and maintaining altitude, the speed was recorded at the moment when visual stall buffet began. There might be a small error in the stall speeds recorded but the overall findings regarding the lift coefficients are well inline with the airfoils used in these planes:

A pic depicting the Göttingen 298 used in the Dr.I. Camel's airfoild is very close to the RAF 14:


The airfoil used in the Camel, third from the top:


Now, lets consider both of these airplanes in steady state, sustained turn. The forces acting on an aircraft in a turn are, gravity, centripetal force, lift, drag (both induced and parasite) and thrust. In a sustained steady state turn, airplane's speed, altitude, turn rate and radius all remain constant and the forces are in equilibrium.



So SCTusk, which one of these forces do you think is affected by the gyroscopic forces of the Camel's engine so much that it makes up for the more lift per weight of the Dr.I? I think we'll both agree at it doesn't work as antigravity device making the plane lighter. So does it reduce drag? In a theoretical sense I think it's clear that it doesn't, but it probably reduces the required control input of maintaining a steady turn compared to the turn to the left and therefore reduces control surface drag and generally makes it easier for the pilot to perform the turn. So does it increase lift? I think we'll agree that it doesn't. Does it increase thrust? Well, the engine turns the prop which in turn provides thrust but I don't think the gyroscopic effects contribute much in the way of thrust.

So SCTusk, please explain how these gyroscopic effects make the Camel turn better than a plane that provides more lift per weight? To which of these forces acting on an airplane during a sustained turn does this gyroscopic force contribute to and how?

[SCTusk]

please explain how these gyroscopic effects make the Camel turn better than a plane that provides more lift per weight? To which of these forces acting on an airplane during a sustained turn does this gyroscopic force contribute to and how?

Perhaps the following extract will convince you that these forces are real and significant:

http://yfrog.com/07gyropj

And of course, as a pure force of nature which would exist even without the aircraft being in flight (it could for instance be taxying) the aerodynamic forces are not affected. This is an additional force outside of the flight envelope which applies to the mass of the aircraft as it attempts to manoeuvre. This is simple physics and I really don't want to embarrass you further on this point.

As for my data from the turn tests, yet again you misunderstand the results. The similarity in the figures achieved only serves to emphasise my theory (that gyro effects are either not modelled or are under modelled).

If anyone reading this still doubts the significance of the effects of gyroscopic precession in a rotary engined aircraft, well Salute! You're in for a treat when you 'discover' this, as a fundamental force it's always fascinating and particularly so when you realise it for the first time.

Whether or not anyone changes the modelling on the Camel, AH WW1 is a great piece of work and very enjoyable.

Wmaker I've reached saturation point with your faulty logic, inability to understand simple explanations and endless demands. I don't see a sheriff badge so I'm just going to move along now, and bid you have a nice day. But I'd like to see the expression on your face if maybe one day you ever took the controls of a sports airplane and got a handful of precession just from the prop spinning, let alone a thumping great rotary engine whizzing around behind it.  I guess you can't help not knowing something but why so stubborn? It's not like I'm trying to preach a flat world or something. Good luck with it anyway, you'll figure it out eventually.... Salute.

[Wmaker]

Perhaps the following extract will convince you that these forces are real and significant:

I never said that they aren't. You still didn't answer the question I asked. Once again Camel and Dr.I both have rotary engines turning clockwise from the pilot's pov. Differences in the distancies between the engines and the CoG aren't going to make the plane with smaller lift coefficient to turn better.

And of course, as a pure force of nature which would exist even without the aircraft being in flight (it could for instance be taxying) the aerodynamic forces are not affected. This is an additional force outside of the flight envelope which applies to the mass of the aircraft as it attempts to manoeuvre. This is simple physics and I really don't want to embarrass you further on this point.

I never claimed that it isn't an intependent force. I said that it has to contribute/interact with the forces that are involved with a turning aircraft.

As for my data from the turn tests, yet again you misunderstand the results. The similarity in the figures achieved only serves to emphasise my theory (that gyro effects are either not modelled or are under modelled).

I should have been more clear. Yes, they don't show a difference between left and right turns but they don't show that Dr.I turns better either. I still am quite sure it does in the game though. I have to do some testing of my own sometime. There are so many handling quirks evident in these planes that tell the gyroscopic effects are very much present. How can you not see them?

From HTC 2.18 version's release notes:

"The Dr.I and the F.1 Camel both use rotary engines. The large spinning mass of these engines makes gyroscopic precession a large factor in how these planes fly. With the clockwise rotating engines of these planes, 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 left will create a pitch down and a yaw to the right will create a pitch up."

One of the wilder effects is how these planes depart sideways after going over the top of a loop when the speed gets too low. That's what I try to use against them while flying a D.VII.

Wmaker I've reached saturation point with your faulty logic,

Right back at you.

inability to understand simple explanations and endless demands.

Regarding the simple explanations...Heh, whatever. You never explained what was needed to be explained. If you keep thinking I don't know how a gyroscope works, that's ok. Whatever.   Endless demands....ahh well...

I don't see a sheriff badge so I'm just going to move along now, and bid you have a nice day.

Yeh, I'm no sheriff here. But you still won't get very far even if there's something wrong with the AH modelling if you can't bring hard data to the discussion which proves your point. Anecdotes can be interpreted in many many different ways.

But I'd like to see the expression on your face if maybe one day you ever took the controls of a sports airplane and got a handful of precession just from the prop spinning, let alone a thumping great rotary engine whizzing around behind it.

Yeh, that is one of the dreams of mine. Allthough, especially with a rotary engined plane, I'd most probably would be scared sh*tless and the expression on my face would probably show that very well.

 I guess you can't help not knowing something but why so stubborn? It's not like I'm trying to preach a flat world or something. Good luck with it anyway, you'll figure it out eventually.... Salute.

I was asking you to prove there's something wrong with the AH's Camel and you never did. That's the first step of getting something changed. I'm well aware of the gyroscopic effects and how they work but I don't see how they overcome significant differences in lifting properties of the wings of airplanes (ie. making Camel turn better than the Dr.I, for example), especially when both planes are equipped with a similar rotary engine.

<S> SCTusk Have fun in the WWI arena!

[hitech]

The reasoning is valid. Repeatedly claiming it isn't does not change the reality of it. The gyroscopic force is not magic, its' cause is well known and well documented. If you were genuinely well aware of it this aspect of the discussion would be unnecessary.

Please enlighten me, I can not think of any reason the forces of a gyro would make a plane turn better 1 way or the other. It appears to me, you do not know either because you just state it, or reference the math of gyro calculation. (to which some one like me will say welll duhhhh, that looks just like the AH code). But you have never posted anything to prove your statement. If a gyro does create a faster turn, it does in AH also, simply because how the forces are applied in AH.

But other then making it much easier to hold the turn, and possibly more drag on the rudder (very minor force), I can not think of any thing that would make the plane turn better.

So if you have any real reference describing or showing the force diagram I would love to see it.


HiTech

[Wmaker]

Please enlighten me, I can not think of any reason the forces of a gyro would make a plane turn better 1 way or the other.

.....

But other then making it much easier to hold the turn, and possibly more drag on the rudder (very minor force), I can not think of any thing that would make the plane turn better.

Totally agreed. This is what I've been trying to say aswell all along.

So if you have any real reference describing or showing the force diagram I would love to see it.

While asking the same thing I am told that I don't know how a gyroscope works and therefore am just embarassing myself.... <sigh>

[hitech]

While asking the same thing I am told that I don't know how a gyroscope works and therefore am just embarassing myself.... <sigh>

I know I am a clueless dolt, hence I am never embarrassed.

HiTech

[Wmaker]

I know I am a clueless dolt, hence I am never embarrassed.

LOL!




Truth to be told, it doesn't bother me either. I make do with what I have and try not to worry about the rest.

[Mano]

Good posts from all of you  <S>.........

I have left posts on this topic before in other flight sim forums and it is a tough subject to explain.
Take off the front wheel of bicycle.....spin it fast and observe what happens when you turn it to the right
......then observe what happens when you turn it to the left. Pull it upward, pull it downward, ect.
If the wheel is spinning clockwise from your p.o.v. it will be easier to turn to the right than to the left and it has a tendency to
move upward. Now, imagine if that bicycle wheel was turning at 1200 rpm's and weighed in at 300 lbs or more as the Clerget,  Le Rhone, or Oberursel engines did in WWI.
You would essentially be flying a giant gyroscope or flywheel with wings.

It may not be possible to model the rotary engine with the current flight sim engine because the
rotary engine was only used in WWI and was replaced by the more advanced radial engine after the war.  Rise of Flight does not have the rotary engine modeled either.
Probably the best we can hope for as flight sim enthusiasts is to see the rotary engine planes modeled with lots of torque and the inline engine planes modeled with less torque.
Any articles you might find on WWI A/C will mention the planes with rotary engines turned to the right faster to the right than the left.........and had to use strong rudder if
they turned left.



Wikipedia Link of the Rotary Engine
http://en.wikipedia.org/wiki/Rotary_engine
Wikipedia Link to Gyroscopic precession
http://en.wikipedia.org/wiki/Precession

Here is a quote from Richard A. King

"Flying the Sopwith F.1 Camel" by Richard A. King, from Flight journal


"The engine is running wide open as I make a smooth left turn, holding left rudder throughout, and the nose moves swiftly along the horizon. A 30-degree bank brings me back on my original heading very quickly.

A right turn is an entirely different and somewhat disconcerting maneuver. Keeping the engine at 1,200rpm and with 120mph airspeed, I bank to the right, wind hitting hard against my left cheek. With the left side of the rudder bar almost fully deflected and my right knee jammed back almost to the seat, I am barely able to maintain a 30-degree bank to the right without the bank increasing. It is not a smooth right turn in any sense of the word. It takes a lot of concentration and a delicate touch with my feet on the rudder bar to maintain the constant angle of bank for the entire 360 degrees of the turn. In reality, it probably took less time to make the 360-degree right turn, but it was fatiguing and seemed to take forever to get back on my original heading.

Every flight I ever made in the Camel was as exhilarating as the first one because these sensations never changed. The 160hp Gnome-powered Nieuport 28 gave the same sensations, but because of its longer streamlined fuselage and small, thin wings, it was a little more comfortable, not just in the turns but in every other maneuver as well.

If the right turn seems to be getting away from you (out of control), usually because you're banking too steeply, the Camel's small rudder is simply not adequate to compensate for the gyroscopic effect. The only solution is to cut the ignition and let the engine rpm slow, which reduces the gyro effect. Then the aircraft once again becomes controllable. [You can even lose control in a left turn if at high power, because if you bank steeply the nose will rise and if you add too much back pressure you can easily stall.] A lot of young, inexperienced pilots failed to understand, especially near the ground. The results were usually fatal.

The Sopwith Camel can stall without too much effort. Its large cowl, propeller, struts, and wires and two machine guns in the slipstream created a lot of drag. When the engine isn't running full out, its speed drops off dramatically. Cutting the ignition and easing the stick past neutral and slightly back will quickly bring about a stall, with the nose falling off sharply, usually to the right.

I never looped the Camel, but anytime I made a loop in the Sopwith Pup, a strange thing would happen: at the top of the loop, when the Pup was inverted, the airspeed having dropped off considerably and with the engine still running at 1,200 rpm, the gyro effect of the rotating engine would force the aircraft to turn 90 degrees to the right. Thus, if you started a loop heading north, at the top of the loop, with the nose of the aircraft heading south, the aeroplane would turn to the east, and when you came out of the loop, you would be heading west. I don't have any idea where the 160hp Gnome Camel would end up if anyone tried the same maneuver. Though I am sure it was done, I have never read about or heard anyone mention the results of looping a Camel in combat"

<S>
Mano