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Author Topic: trimming  (Read 1767 times)

Offline bob whitney

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trimming
« on: July 29, 2019, 10:30:09 PM »
 on top 5 sat at this years nats I mentioned to Paul Walker that I had trouble with my E Scorpio in the top right corner of the Hour glass until I went to a clockwise prop ,he sort of grunted and said it was all in the trim ,not the prop. Paul was not having a good day so I didn't want to bother him any further so didn't ask anymore questions ' 

I am still open to ideas of what I should be looking for as far as trimming to make that corner with a CC prop
rad racer

Offline Tim Wescott

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Re: trimming
« Reply #1 on: July 29, 2019, 10:42:51 PM »
In a sense you can ask Paul.  He has a multi-chapter series on trimming.  He's published it in Stunt News, and here, in FlyingLines.org.  If I taught a class in control line stunt, it would be required reading, before, during, and after trim sessions.  I have a copy in my flight kit.

I suggest you go through it in as much detail as you can stand, and do what he says -- it helped my flying tremendously, even when I was a beginning pilot.  Having a helper who can see what the plane is doing is, well, a help, but you can go far without it.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline bob whitney

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Re: trimming
« Reply #2 on: July 30, 2019, 08:42:54 AM »
I try to read as much of his stuff as I can
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Offline Howard Rush

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Re: trimming
« Reply #3 on: July 30, 2019, 08:54:06 AM »
Clockwise looking from the front or the back?
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Offline Tim Wescott

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Re: trimming
« Reply #4 on: July 30, 2019, 10:02:50 AM »
Clockwise looking from the front or the back?


"Ford or Honda" if you're a car guy.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Trostle

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Re: trimming
« Reply #5 on: July 30, 2019, 10:12:25 AM »
Clockwise looking from the front or the back?

Is not the convention to define the prop rotation when looking forward from the back of the prop?

Keith

Offline bob whitney

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Re: trimming
« Reply #6 on: July 30, 2019, 11:09:55 AM »
I think we all started out counter clockwise facing the motor from the front H^^
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Offline Howard Rush

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Re: trimming
« Reply #7 on: July 30, 2019, 11:11:16 AM »
Is not the convention to define the prop rotation when looking forward from the back of the prop?

Maybe so from a pilot's perspective, but my cockpit canopy is painted on, so I can't see out.
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Offline Howard Rush

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Re: trimming
« Reply #8 on: July 30, 2019, 11:57:45 AM »
I can tell you my limited experience without knowing the answer to the rotation question.  My first electric Impact has the up line behind the down line.  It can be trimmed to work well with either prop direction.  My second Impact has the down line behind the up line.  It does perverted things on the second hourglass corner and the outside squares with a backwards prop (clockwise looking from the front, negative rotation about the X axis).  I switched to a clockwise-looking-from-the back prop and all was well.  My preferred prop only comes in clockwise looking from the back, so I didn't pursue trimming the second Impact with the backwards prop. 
The Jive Combat Team
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Offline Tim Wescott

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Re: trimming
« Reply #9 on: July 30, 2019, 01:37:07 PM »
Y'know, if we just say "right hand" and "left hand" for prop rotation, similar to a screw or bolt, then we don't have to get into the whole "pusher/tractor" "clockwise/counterclockwise" (or "Ford/Honda") snarl.

A typical glow engine, mounted on the front of a plane, takes a prop with the same chirality as a right-hand screw.  That's "right hand", or "tractor" if you're stuck in glow engine land (although I've never seen a tractor with either a glow engine or a propeller, but there you go -- you never know what those farmers will do to get their crops in).  Put the glow engine on the back of the plane, and once you've sorted out the CG difficulties, you need to put a left-hand prop on it (i.e., pusher, although I've never been sold drugs by a guy with a propeller -- it would certainly be an interesting experience).
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

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Re: trimming
« Reply #10 on: July 30, 2019, 02:04:15 PM »
Y'know, if we just say "right hand" and "left hand" for prop rotation, similar to a screw or bolt, then we don't have to get into the whole "pusher/tractor" "clockwise/counterclockwise" (or "Ford/Honda") snarl.

A typical glow engine, mounted on the front of a plane, takes a prop with the same chirality as a right-hand screw.  That's "right hand", or "tractor" if you're stuck in glow engine land (although I've never seen a tractor with either a glow engine or a propeller, but there you go -- you never know what those farmers will do to get their crops in).  Put the glow engine on the back of the plane, and once you've sorted out the CG difficulties, you need to put a left-hand prop on it (i.e., pusher, although I've never been sold drugs by a guy with a propeller -- it would certainly be an interesting experience).
You probably think that you understand what you thought I said but what you don't realize is what you heard is not necessarily what I meant.

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Offline Tim Wescott

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Re: trimming
« Reply #11 on: July 30, 2019, 02:39:31 PM »
You probably think that you understand what you thought I said but what you don't realize is what you heard is not necessarily what I meant.

Actually, it's a serious attempt to reduce frustration, but I was having way too much fun.

So, seriously: point your right thumb at a screw hole.  Curl your fingers.  Your fingers are turning in the direction you need to tighten the screw.  In engineering and physics, that's the "right hand rule" (more or less -- don't argue, Howard).

Now point your right thumb at the bore of a prop.  Curl your fingers.  If you spun the prop in that direction and it wanted to fly in the direction that your thumb is pointing, it's a right-hand prop, just like a right-hand screw.  If you were to spin it that way and it would want to climb up your thumb, then it's a left-hand prop.

And a right-hand prop will always be like a right hand screw, and we don't have to argue about what's tractor or pusher or clockwise from the back or anything.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

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