Quick Question About Single Engine Planes

[Random8145]

Hey, this is a question that has been bugging me for some time now, but, if helicopters have to have a tailrotor or a secondary rotor to prevent the fuselage from turning in the opposite direction that the main rotor is turning, for single engine prop planes, what prevents the plane from turning in the opposite direction of the propeller? Shouldn't if the propeller spins one way, the plane turn the other?

I am guessing it has something to do with as the plane travels through the wind, it presses on the wings a certain way, but what about those aerobatic planes that can hang on their prop? They don't rotate when they do that (unless my memory is wrong). Also planes like the F-16, which has a single jet engine. I would imagine that engine turns with some force.

What prevents the plane from spinning?

 

[Brett327]

Hey, this is a question that has been bugging me for some time now, but, if helicopters have to have a tailrotor or a secondary rotor to prevent the fuselage from turning in the opposite direction that the main rotor is turning, for single engine prop planes, what prevents the plane from turning in the opposite direction of the propeller? Shouldn't if the propeller spins one way, the plane turn the other?

I am guessing it has something to do with as the plane travels through the wind, it presses on the wings a certain way, but what about those aerobatic planes that can hang on their prop? They don't rotate when they do that (unless my memory is wrong). Also planes like the F-16, which has a single jet engine. I would imagine that engine turns with some force.

What prevents the plane from spinning?

Inertia. Little prop=little force (it does actually have an impact on flying characteristics), big rotor=big force=need tail rotor.

Brett

 

[skidkid]

The rudder counteracts the lesser torque (p factor?). In the T-34 you needed to add right pedal to power increases.

 

[Single Seat]

The rudder counteracts the lesser torque (p factor?). In the T-34 you needed to add right pedal to power increases.

P-factor is the decending blade creating more lift than the acending blade, at higer angles of attack.

 

[Swanee]

This is more apparent in a tail-dragger on the ground during taxiing. As was stated before, you do experience some torque steering as you increase power.

You can also see the effect if you go to your local airshow and see an extra 300 performance. They like to climb vertical into a stall and roll the airplane using the torque from the nice big engine.

 

[skidkid]

P-factor is the decending blade creating more lift than the acending blade, at higer angles of attack.

Guess I should have spent more time in the aero books and less time at Flounders, good catch.

 

[PropStop]

Guess I should have spent more time in the aero books and less time at Flounders, good catch.

I disagree strongly with this statement.

 

[Brett327]

This thread can only end in a battle of the aero-engineering mongoloids. Save yourselves while you still can.

Brett

 

[Single Seat]

Guess I should have spent more time in the aero books and less time at Flounders, good catch.

Crap you wish you could forget. I'm actually drinking a jim beam and coke out of an old flounders jar!

This thread can only end in a battle of the aero-engineering mongoloids. Save yourselves while you still can.

Brett

Fuck that, back to drinking and chasing ass up and down the beach.

 

[A4sForever]

This thread can only end in a battle of the aero-engineering mongoloids. Save yourselves while you still can.

Brett

Which is why I dropped out of Aero Eng and went Far East ...

Plus ... I got a red TR-4 and discovered wine, women, and song ...

 

[Single Seat]

Plus ... I got a red TR-4 and discovered wine, women, and song ...

It sounds so much more eloquent the way you put it.

 

[HAL Pilot]

They do turn opposite or "spin" to some degree.

For the most part, U.S. aircraft are built with propellers that turn clockwise (right) when viewed from the cockpit. Because of this, they have left turning tendencies. The left turn tendency is caused by three things:

• P Factor: the downward blade (on the right side) has a higher angle of attack so it gets a "bigger bite" of the air. This causes a left yaw.
• Slip Stream: The the air from the prop goes in a spiral around the aircraft and ends up hitting the left side of the vertical stabilizer, again causing a left yaw.
• Torque: The prop turns to the right so the engine tries to go opposite (to the left). Since the engine is attached to the aircraft, the aircraft tries to roll left.

There is a fourth turning tendency, but it can be in any direction. During a climb it is a right turn tendency. It is called gyroscopic precession. A spinning prop has some of the properties of a gyroscope. If you apply a force to a gyroscope, you will get a resultant force (precession) occurring at a point that is 90 degrees in the direction of the spin. When you climb, you apply a force to the top of the propeller (i.e. push it back so it angles upward). The resultant force is felt 90 degrees to the right where the prop will also be pushed back, causing a right yaw. It is just opposite in a descent (left yaw). Similarly a left turn or yaw will cause a upward precession and a right turn or yaw a downward precession.

The aircraft are engineered so that in level flight at cruise speed, these forces are "trimmed" out. This is usually done with trim tabs, either fixed or movable. The size of the vertical stabilizer and rudder have a lot to do with this too. During descents, when there is less power on the engine, these factors are less noticeable. During takeoff and climb, when there is more power producing more of these forces, the pilot uses right rudder to counteract them.

I hope this helps but I'm not an aero guy and this is just my layman's explanation. Anything more just gives me headaches.

 

[HAL Pilot]

This thread can only end in a battle of the aero-engineering mongoloids. Save yourselves while you still can.

Brett

I wish I had seen this before I posted. I started typing my answer when Brett's first post was the only response. I got stuck on the phone midway through. Hung up, finished and hit the post key to find a bunch post - this being the key one.

For all you aero mongoloids that want to tear my answer apart, have at it. I won't argue. It's all I got and it was digging deep to come up with what I wrote....

 

[Brett327]

I wish I had seen this before I posted. I started typing my answer when Brett's first post was the only response. I got stuck on the phone midway through. Hung up, finished and hit the post key to find a bunch post - this being the key one.

For all you aero mongoloids that want to tear my answer apart, have at it. I won't argue. It's all I got and it was digging deep to come up with what I wrote....

It's all good, big bro. That was probably the least nerdy way to answer the question accurately.

Brett

 

[HAL Pilot]

It's all good, big bro. That was probably the least nerdy way to answer the question accurately.

Brett

I wasn't worried about the nerdy part - I just didn't think about the high probablity of someone jerkoff nickel and diming my answer to death because I left an i undotted or did not show the proper equations....