3D CG MOVEMENT IN FLIGHT CG CHANGE ?

[ULTIMATE1]

I have and idea i'm goin to try by putting my batterry packs in a sliding tray and using a retract servo with pulleys to have the battery packs slide to the rear when I switch to flight mode thre for 3D. Anyone have any input on this idea or ever tried anything like this I know alot of fliers add weight to the tail for there 3d freestyles . I think being able to change your CG with a flick of the switch to high rate would work with the right design????

[Wild Thang]

Awesome idea! If you can pull it off, it would be sweet for freestyle flying! You know... 3D with a hint of IMAC on the side...

[ULTIMATE1]

Anybody have any thoughts on this one?

[aviti]

I've found that a plane doesn't need to be tailheavy to 3D well or nose heavy to IMAC well. The CG being in just the right spot makes the plane very neutral for precision and also good for 3D. That being said I wouldn't want to move the CG in flight. Just my opinion but others may see it different.

[3ddd]

i remember someone tried this a few years ago and it took too much movement to make it realistic for a servo to do it.if you had a jackscrew servo this might work better

[ULTIMATE1]

Yeh but with the right pulley system you could easily move the pack a foot if need be?

[Breakstuff5050]

Great Idea, i've always daydreamed about it but figured there would be too much added weight to do any good. I also agree that having the CG in the "perfect" spot is the proper way to do it. But then again you could throw the cg waaay back during flight and do some pretty intense tail slides or easily back it down really fast and long distance. And who knows what else you might come up with, imagine a normal blender, then when you get low, flip the switch, throttle up and start controllin the plane to do a rising flat spin. Its a good test idea.

[ULTIMATE1]

	Quote: Originally Posted by Breakstuff5050
	Great Idea, i've always daydreamed about it but figured there would be too much added weight to do any good. I also agree that having the CG in the "perfect" spot is the proper way to do it. But then again you could throw the cg waaay back during flight and do some pretty intense tail slides or easily back it down really fast and long distance. And who knows what else you might come up with, imagine a normal blender, then when you get low, flip the switch, throttle up and start controllin the plane to do a rising flat spin. Its a good test idea.

Bill Hemple says he can flat spin his 52% Weeks to the deck and then power up and climb back out in a flat spin would love to see video of this. Imagine the tumbling manuevers you could do with the CG away back there?

[LawnJockey]

I would use a sail winch servo. More movement.

LJ

[JimC-MD]

	Quote: Originally Posted by LawnJockey
	I would use a sail winch servo. More movement. LJ

This is from memory, but that is exactly what a TOC competitor was said to have done in years past. Pulley system with a wieght on it and a sail winch servo. This was back in like 98 as I recall. If it is still in use I do not know.

[snap]

A couple of pilots tried a moving tray after QQ Intoduced 3D years ago, the results sucked and it was abandoned. I balance for neutral center and latteral balance. From there you can 3D or Imac.A couple of years ago I mounted a stud to the firewall where I could reach it and drilled some lead that I could slide on with a locknut it worked really good for adding nose weight in a hurry.

[SofaKing]

If you found the "perfect" CG, then it would not take much weight at all and very little movement to have the desired effect if the weight starts out exactly on the CG point.
Think about it, do the math all you engineer types. Its all about fulcrums

[ULTIMATE1]

I've got Jason Shulman's how to 3D DVD and he has a wingtube socket under the stab that he fills with lead for his 3D freestyle events

[Jarsu]

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[mighty9]

i actually made a tray to do just this about 6 years ago ..i gave it to bill sr @hobby barn to try .....it was just a a set of carbon fiber tubes with a series of pullies and a nylon block that the batteries attached to it moved about 9 inches with a stock servo....the actual cg change was minimal and could not really be noticed on a 1/3 scale plane......i made another and placed it in our dave patricks extra 120 size and it was very noticeable ...you could make it snap on a dime and tame it down to land like a cub......i dont think i have any pictures of it but maybe they still have it at hobby barn ill ask next time im in there...Cris