GScholz more ont turbo props:

[Tails]

Originally posted by hitech
You sure thats what P factor is?

And with all this torque discusion, want to give the diffenition.

Torque is when you wake up in the morning with an erection. Go to take a Pee, push it down, and your feet fly off the floor.


HiTech

Heh, actually that would be jet-thrust.

 Semi-seriously, this is how octipie get around. They suck in a bunch of water, point themselves in the direction they wanna go, and letterrip!

EDIT: And Hitech, in responce to your question about the scale of jet engine torque: I have no clue. How ever, it is significant enough to need to be compensated for in a hydraulicly boosted, non-flybywire fighter. Like in the Su-27 I mentioned earlier, where when doing very low speed maneuvers they have to apply a little rudder to compensate for the torque, and in any manuever where the aircraft is supported entirely by engine thrust (IE A tail-slide in a Su-27, or the MiG-29's 'hovering trick') they have to throttle one engine back a little, so that asymetric thrust helps to compensate for the torque. So it's there and noticable.

[JB73]

Originally posted by hitech
Torque is when you wake up in the morning with an erection. Go to take a Pee, push it down, and your feet fly off the floor.

i FINALLY understand something in this thread!!!!

[Straiga]

We automatically take care of this with ailerons in keeping the wings level, and it really doesn't take much force from the ailerons to do it. On the ground, all torque forces are countered by the wheels.

Hitech with all due respect this is absolutley wrong Im sorry. Someone had a post about a B-24 on takeoff and this B-24 pilot said he used no aileron or aileron trim for takoff just rudder. How come you cant see that this is how a 4 engine airplane actually flys and that your use of aileron is wrong in takeoff or in cruise flight.

Torque is pronounce at the first onset of power output. You would be in the ditch, before you could counter torque with effective aileron on takeoff. Think about that.

Hey T1loady ask your C-130 driver if he has ever had to use aileron for takeoff to counter torque roll. I bet he only uses aileron for cross wind takeoffs. Torque roll on the ground is a yawing torque and countered by RUDDER not aileron.

T1loady have him discribe exactlly to us all what happens to a C-130 on takeoff and what controlls and trim settings are used in takeoff and how the plane flys in cruise. May be we can all learn something here. I will be waiting for your post.

Tails that is a very good explanation of torque in turbines and turbo props. So I guess torque does affect an airplanes airframe.

But GScholz still wont believe what you say. Because you have actual experience on the subject. I guess having real experience either working on them or flying them, I guess we dont know what we are talking about. Its interesting that someone who has never flown a jet or multi-engine turbo prop really believes they are right reading from a book, and that these planes should fly like they think, but if they actually flew these airplanes they would be shocked, that what they think of how it will fly, just doesnt happen. Its really sad.  
When you go for a pilots liscence who do want to listen to teach you how to fly and can get your ticket, maybe someone with a flight instructors certiticate and thousands of flying hours or a computer pilot flying a flight sim who he think he knows it all.

GScholz thats a good picture, it proves my point that you have an extensive knowledge of not knowing how to properly fly an airplane or how it works. Did your chute work the way you thought it would or do you need someone to explain it to you? Oh! your not going to listen anyway.

GScholz, when I say Im a pilot and have flown for many years, this is not to bragg, I could care less if your Impressed or not. Im  just saying that I have been there, and done that. I dont think that other people think Im bragging and I dont think I have come across like that either. Im just letting everbody know where Im coming from with my experiences. If this offends you to make snide remarks so be it.
 

If you had actual experience in something that I have not had I would listen or read the information. I could learn from that and say wow I didnt know that. I have learned something new. But Im not going to listen to any flight sim pilot trying to tell me how a real airplane flys or what makes it work. Im sorry they just dont know.

You may think I dont want to listen because I think I know it all. Thats far from it, but I cant agree with someone who thinks they know how, without experience how a certain type of airplane will fly.

When I interviewed with the airline Im at now I was competing against over 40,000 applacants for the same job. Whats the odds, so why did I get the job and the others didnt. It just may be I had more experience than the others. Its probably like getting into pro sports.

I have been told that experience dosent give you knowledge about a subject, you will know more by reading a book. Would you enjoy sex more by reading a book or by actually doing it. What do you think?

Being a single engine pilot does not give you experience in knowing how to fly a multi-engine airplane. Flying a jet is different than flying a piston airplane. You think you might know but until you flown them, then and only then is when you will know the differences on how they fly.

Straiga

[straffo]

Straiga I think you're just not using the correct vocables/words.

If we apply full power to a  B24 without propeller , torque will still be present.

Agree ?

Now will this force be enought to make the B24 turn on place ?

I don't think so.

[hitech]

Straiga: Are you saying T1loady's definition of P-factor is correct?

[Casca]

HiTech's definition of P Factor from the Ramskill article is correct.

[hitech]

If you had actual experience in something that I have not had I would listen or read the information. I could learn from that and say wow I didnt know that. I have learned something new. But Im not going to listen to any flight sim pilot trying to tell me how a real airplane flys or what makes it work. Im sorry they just dont know.

This is what you are totaly incorect about. I have no doubt that when you tell me such and such a plane does this on a take off roll. That your are correct. But if you wish to talk experience you want to count your flying experience toward your expertiese in physics. You could just as will say your flying makes you an expert in sex. Because flying is not physics, it is flying.  Your analagy is the same as saying that having sex 5 times a day, for 20 years makes you a PHD in the humun repoductive system. You might know how to use it. But that in no ways equates to knowing what makes it work.

Belive it or not some of us have a much greater knowledge of the physics of flight than you. Also some of us like to debate to gain a greater understanding of how things work. This turbin/ turbo prop discusion was one of those. You tend to just always state this is the way it is, and then when you try post why, your arguments tend to be incorect.  So you can state that your experience tells you a Hybass fan has torque.  But when you stated why, your analisis was totaly incorect. You also stated another one that when you spun up a turbin from 5000rpm to 30k it had torque. Now once again, I do not debate that it does. You have done it, and seen it. But your resone given is not accurate. You stated it was because you were accelerateing the turbing, that acceleration caused the plane to rotate the other way. This again is not entirely accurate. We could analize exatly why it is. But quite frankly I  am tired of your wanting to sight your expertise as to why you are correct. Wrather than looking deaper into a problem and solving it. Or be able to precisly argue why something is.  Of course you never need to look deaper, because you already know absolutly every thing about planes.


HiTech

[Straiga]

Straiga: Are you saying T1loady's definition of P-factor is correct?

No this is not correct. P-factor is the unequal lift produced on the prop disk oposing relative wind.

Since all our props turn to the right, that means there is a force trying to twist (roll) the airplane to the left. Note that this force is about the ROLL axis - the torque forces do not by themselves TURN or yaw the plane as do the previous two effects. We automatically take care of this with ailerons in keeping the wings level, and it really doesn't take much force from the ailerons to do it. On the ground, all torque forces are countered by the wheels.

This is also incorrect about a 4 engine aiplane. Knowing physics I dont think so or this statement would be true.

I may not explain myself very well when it comes to physics. A lot of times in very early in the morning is when I post. My last physics class was over 25 years ago. But in the end, I have said what was right was right.  Wouldnt you agree.

So everybody tell me what degree you have in aerodynamics, any kind of aerodynamics. You to hitech. I have told you about me, now what about you.
1.
2.
3.
4.

Anybody!

Im I the only one with and aeronautical engineering degree here.


Also tell me when you last flew a multi-engine and when did you get your liscence. I have told you my experiences, how about you lets here.
1.
2.
3.
4.

Anybody!

Im I the only one here with a multi-engine certificate and have actual 4 engine flight experience, also 3 engine flight experience and 2 engine.

If you cant respond because you dont hold a multi-engine certificate. This will inform me that you have no formal experience in the subject matter. Physics on paper is one thing flying the plane is different. Statements like the above quote proves this fact.

According to physics bumble bees cant fly either.

Straiga

[hitech]

quote:
--------------------------------------------------------------------------------
 Since all our props turn to the right, that means there is a force trying to twist (roll) the airplane to the left. Note that this force is about the ROLL axis - the torque forces do not by themselves TURN or yaw the plane as do the previous two effects. We automatically take care of this with ailerons in keeping the wings level, and it really doesn't take much force from the ailerons to do it. On the ground, all torque forces are countered by the wheels.
--------------------------------------------------------------------------------


This is also incorrect about a 4 engine aiplane. Knowing physics I dont think so or this statement would be true.

_____________________________ ________________

Ok please explain one topic. How does adding or moving engines change the Torque effect. Please do not speak to P-factor/slip stream or preccesion. Just about Torque. I.E. a rolling moment created only by the force of the engine.

Because I view that statement about engine torque to be 100% accurate.

Because you could put those 4 engines in a straight line all behind each other, or out on the wings. And the roll force on the the air frame do to engine torque will be exatly the same.

If you do not agree with this, please explain presicly why.

As to my credentials. They are irrelavent. I never use my credentials to prove or disprove a point. Either the argement can be shown to be true or not.



HiTech

And just so you know

According to physics bumble bees cant fly either

Is an old myth. Was shown how they fly many years ago.

http://www.wolfson.ox.ac.uk/~ben/zetie1.htm

[g00b]

Allow me to summarize.

The compressor creates some torque.

The spinning mass of air dragging on the stators, combustion chamber walls/thrust tube/exhaust also create some torque.

But most of the torque comes from the gearbox.

Agreed?

Some wrong theories.

A turbo-prop is NOT like any other motor. Not an electric one, not a reciprocating internal combustion, etc...

HiTech "Because you could put those 4 engines in a straight line all behind each other, or out on the wings. And the roll force on the the air frame do to engine torque will be exatly the same."

Um... the toque applied the airframe will be the same, however the moment arm to the center of mass will change, which changes the force from a rotory one to a linear one... I think. Which means engines on the tips of the wings would apply less of a rolling force to the aircraft... I think.


Straiga, I have a huge respect for your wealth of experience. But be aware some of us may have a fair amount of knowledge on the subjects at hand as well.

Since you asked, I don't hold a degree but I do design record setting streamlined Human Powered Vehicles, the most aero-efficient vehicles on the planet.

[HoHun]

Hi Straiga,

Seeing we had good success with tackling the single-engine torque question by looking at the interacting forces, I'd like to suggest to try the same approach for the multi-engine problem.

For example, we could have a look at a multi-engine propeller-driven aircraft in slow flight on a stable, level flight path.

I'm confident that Hitech is correct that the engine torque is acting on the airframe. I'm also confident that you are right that use of rudder is the correct piloting technique for ensuring the stable, level flight path.

So the question is now, what would happen if

a) we held the rudder centered and fed in aileron to compensate for the engine torque?

b) we held ailerons neutral and fed in rudder to compensate for the engine torque?

c) We held all controls centered? (Probably not necessary because we all seem to agree that we have some kind of asymmetry in the system, but included for the sake of completeness.)

Maybe that's a better approach than looking at a complex situation as we have at the take-off where all parameters change dynamically :-)

Regards,

Henning (HoHun)

[hitech]

Um... the toque applied the airframe will be the same, however the moment arm to the center of mass will change, which changes the force from a rotory one to a linear one... I think. Which means engines on the tips of the wings would apply less of a rolling force to the aircraft... I think.

Nope torque dosn't have a moment arm.

moment arm * force   =  torque.

In the engine case we are not appling a force , just a torque.

A force would be adding the thrust to the airplane, if that thrust is off center it will create torque in some axis.

When adding torque to a system, there is no need to know where that torque is applied when computing the total systems torque.

HiTech

[Golfer]

a) we held the rudder centered and fed in aileron to compensate for the engine torque?

You'd keep rolling left, take out some runway lights, dig in your left main gear and get stuck in the mud.  Hopefully it would still be on its legs.

b) we held ailerons neutral and fed in rudder to compensate for the engine torque?

 

This is what you're supposed to do in a no-wind situation.  Ailerons control the roll of the aircraft, so if there is a yaw movement in the airplane, you're swatting at a fly with a hollow tennis racket.

c) We held all controls centered? (Probably not necessary because we all seem to agree that we have some kind of asymmetry in the system, but included for the sake of completeness.)

Same as using only aileron.  Rolling left, take out some more runway lights, hit the same ditch you made earlier and this time rip off your left main landing gear.

[Golfer]

And Straiga, I have flown 'Texas Raiders'

B-17G.  Not typed, no LOA and no formal school.  But I moved the yoke around.

[HoHun]

Hi Golfer,

Argh, remember that we're already flying way above the runway, and that I'm not a native speaker :-) No idea what I'm supposed to do with a tennis racket! "There is no body checking in golf!" ;-)

Regards,

Henning (HoHun)