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HelicopterFlybarless Rotor Head SystemsOther › Relationship between inner swash and blade grip​arm length....
12-22-2008 07:39 PM  8 years agoPost 1
Droid

rrElite Veteran

Deep down in the​Southwest- UK

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Noticed that many systems on here are using blade grip extensions, is this calculated mathematically, or is just a direct relationship to getting the throw required at the blade grip??

Would it be possible to use the fixed washout base ( i know it ain't a washout but y'all know the bit i mean!!)as a lever to increase throw at the blade grip??

Quotes may have been changed for my own amusement

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12-22-2008 08:07 PM  8 years agoPost 2
duke666

rrKey Veteran

Hampshire, UK

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Hi Droid,

Do a little search here and you'll easily find your answers and there's alot of pics to show the various conversions.

Duke

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12-22-2008 08:16 PM  8 years agoPost 3
tchavei

rrProfessor

Portugal

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Actually the problem is the opposite. A direct link between the swash and the grips produces too much throw which then will lead to reduction in servo atvs which will lead to lower resolution. The biggest pain has been to increase the grip bolt distance from center to reduce the swash effect on the main blades. Another problem that unfortunately arrises from this is that since the link that goes to the grip isn't at 90 degree to the grip arm bolt, you will have more throw on one side than the other. A solution would be to make the extensions with a vertical offset but nobody has spent enough time to do that.

Tony


--------------------
"Perfection and patience usually walk side by side..."

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12-22-2008 08:17 PM  8 years agoPost 4
MrMel

rrProfessor

Gotland

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All ends leads to the end result, which is:

a) you want sufficent pitch range
b) you want +-10 to +-12 cyclic pitch

All "flybarred" head need to either use extender or as you say, a mixingarm in the middle with stock head.

Both ways will do the work.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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12-23-2008 02:09 PM  8 years agoPost 5
Chuckie

rrKey Veteran

Crofton Maryland

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Look at the relationship of the links and arms from the servo arm to head in the Logo 600 and you have a 6 to 1 total ratio. The servo moves 6 degrees for every 1 in the head. When you convert a flybared heli and remove the bell/hiller mixer the ratio changes, gets worse. Also, the mechanical advantage bell cranks actually work opposite to what you want in a FBL heli causing the ratio to be even further off the mark.

You can see by the designs/changes out there most focus on improving the ratio by moving the blade grip arm ball further away from the main shaft. The other is reducing the ball distance on the servo arms. However, none of these get the heli to mach the ratio in the Logo models. Moving the balls further out on the outer ring of the swash as well as moving the balls further in on the inner ring will improve the ratio. The best place to impact the ratio is at the bell cranks. The problem then becomes dealing with moving the bell cranks and or getting the rods to be aligned correcly at mid stick, ie 90 degrees.

I assumed vbar software was optimized for the Logo (600) mechanical ratio and don't know how other FBL electronics would work with different mechanical ratios.
Would it be possible to use the fixed washout base ( i know it ain't a washout but y'all know the bit i mean!!)as a lever to increase throw at the blade grip??
Yes, some have converted the Trex 600N and kept the mixer from the flybar carrier but as tchavei nicely stated you would want to reduce the throws to the head not increase them.

Charles

Please stand by for faster service!

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