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Old 03-02-2013, 12:48 PM   #281
kdsguy1
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i am very interested in getting theses on both my 550e, and 450 pro v2!!!, please pm me or send me a link on both the 550e i have the new desighn tail v2 silver
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trex 550e v2, 7200bx, cc100, cc bec pro, edge 523trex 450pro v2 7200bx, dx8 edge blades, hs5065 mg, kds 450sv,
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Old 04-09-2013, 05:06 PM   #282
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Are they available for Raptor 50 Titan?

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Old 04-11-2013, 08:29 AM   #283
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sorry to butt in, but i don't understand the logic of why making the grips heavier would make it easier for the slider to move under load. as the weight is the same each side, wouldn't any positive or negative effect be exactly counteracted? i've searched around the net but can't find any theory. and why is it called 'the tennis racquet effect'? its puzzled me for a while.
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Old 04-11-2013, 10:07 AM   #284
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Default Re: Review - Heim Joint's "Tennis Racket Effect" mod for helis

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Originally Posted by neverland View Post
sorry to butt in, but i don't understand the logic of why making the grips heavier would make it easier for the slider to move under load. as the weight is the same each side, wouldn't any positive or negative effect be exactly counteracted? i've searched around the net but can't find any theory. and why is it called 'the tennis racquet effect'? its puzzled me for a while.
As you can see by the age of the thread that it never caught on. It's just something that doesn't exist in reality. It's like the magnetic bracelet for rc helicopters.
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Old 04-11-2013, 10:52 AM   #285
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well i did the mod on my 450 anyway, but couldnt tell any difference tbh. saying that, its not any worse!
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Old 04-11-2013, 02:33 PM   #286
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i had a 'lightbulb' moment. the weights are to counteract the control arm sticking out from the blade holder, which, due to centrifugal force, 'prefers' to be in line with the blade holder when the blades are spinning, so forcing the tail slider into the '0' degree position where it likes to stay. if the projecting 'chinese weights' are the same weight as the control arm, and at 90 degrees to it, the forces should be balanced out. ie the position of the blade axis wont be forced into any particular position. with the result that the tail slider should move along the shaft with little resistance. dead simple when you think about it
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Old 05-29-2013, 06:02 PM   #287
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Quote:
Originally Posted by neverland View Post
i had a 'lightbulb' moment. the weights are to counteract the control arm sticking out from the blade holder, which, due to centrifugal force, 'prefers' to be in line with the blade holder when the blades are spinning, so forcing the tail slider into the '0' degree position where it likes to stay. if the projecting 'chinese weights' are the same weight as the control arm, and at 90 degrees to it, the forces should be balanced out. ie the position of the blade axis wont be forced into any particular position. with the result that the tail slider should move along the shaft with little resistance. dead simple when you think about it
I think you pretty much nailed it with one exception. Even with the counter weights on ether side, it still will not counter the force of that control arm wanting to in center very well since the weight still will be mostly on one side. What would be better, is if we could add equal weight directly opposite of that control arm. Short of having custom grips molded like that, it's not easy DIY task. I have resorted to flipping my grips so that those control arms are in line with the centrifugal forces. Trailing edge instead of leading edge. Seems the tail is well behaved that way for me.
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Old 05-29-2013, 08:38 PM   #288
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I posted a graphical explanation here in post #1 http://www.helifreak.com/showthread.php?t=516097
The weights do not have to be equal on both sides, just the sum of the torques they produce needs to equal and opposite to the tennis raquet torque of the original tail system.

Last edited by HEIM JOINT; 05-29-2013 at 08:41 PM.. Reason: fixed link
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Old 05-30-2013, 07:44 PM   #289
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Quote:
Originally Posted by HEIM JOINT View Post
I posted a graphical explanation here in post #1 http://www.helifreak.com/showthread.php?t=516097
The weights do not have to be equal on both sides, just the sum of the torques they produce needs to equal and opposite to the tennis raquet torque of the original tail system.
Thanks, I totally forgot about the blades.


Ok, now that I got a chance to sit down and read it thoroughly, it makes sense now.
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Old 09-01-2013, 11:30 PM   #290
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Quote:
Originally Posted by Helico-pteron View Post
As you can see by the age of the thread that it never caught on. It's just something that doesn't exist in reality. It's like the magnetic bracelet for rc helicopters.
This is adapted from real helicopters...sooo, its not a "magic bracelet" really... just saying.
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Old 09-01-2013, 11:32 PM   #291
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Make these for a Goblin 700? I got some from you a year or more ago for my old, now long gone trex 450 and 600's in the past.
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Old 09-02-2013, 08:54 PM   #292
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Quote:
Originally Posted by Helico-pteron View Post
As you can see by the age of the thread that it never caught on. It's just something that doesn't exist in reality. It's like the magnetic bracelet for rc helicopters.
I would advise not saying that out loud amongst knowledgeable helicopter people, you will be demonstrating your ignorance. My videos on this prove the affect of the weights and many experts on this forum have proven the effect also. Full scale helis also use them so this is not snake oil. If you care to understand the physics that cause it you can look at my pdf here post #1 http://www.helifreak.com/showthread.php?t=516097

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Old 09-03-2013, 02:11 AM   #293
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It would be neat if the tail holder arms were designed so that if the tail control become detached in some way (ball, arm, etc) the blades would naturally (tennis racket effect) go to a near 3 or 4 degree pitch so that the heli would not piro very fast which would make it easier to control instead of going to zero degree pitch which is where most would go.
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Old 09-03-2013, 05:58 AM   #294
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That could be done but the pushrod force would have to be substantial again to do it.
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Old 09-03-2013, 11:55 AM   #295
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At least the tennis racket effect could be listed as a feature by the designers then .
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