Hang Test (Method of hanging)

[asra]

Howdy ALL !I did my haing test from a loggin'chain hung between two pine trees and used a come-along to crank her up.... With Sonny j's Vaulable help i finally got the beastie to haing 10 degrees nose down with me in the saddle...and a half a tank of fuel..... and my boots... and my helmit.... geez i didn't know a haing test was so picky ! hehehehe!and Yes the little amount of weight realy does make a differance ! My boots add half a degree ! HEHEHE !C ya !Bob....

[NiqueNaque]

Bob,Did you balance it on the mains as well to check the vertical centre of gravity?Nick.

[asra]

Sam,When the hub bar is rotating at speed there would be less deflection than if it were statically loaded. More deflection equals more stress. I am sure that the forklift idea is ok however I would rather use a support tube on the jesus bolt and hang it direct, 3/4 inch Aluminium isn't that tough, especially if the forks are lowered quickly with a sudden stop! Just my two bobs worth!Question? Are you supposed to chock the head at any particular angle?John M

[asra]

JohnBefore the hang test I had my doughts about using the hub bar, but now after using this method, I wouldn't hesitate to use it again.And yes the fork operator must be gental, and the padded forks placed as close to the rotor head as possible.My machine is also very light compared to the heavier 4 strokes, 2 seat machines, fitted with pods etc.As for the torque tube, yes it must be chocked so it remains in the centre of its 18 degrees of movement.During my hang test I manually held it, but this puts extra stain on your controls. I forgot to make a chock and took the lazy way out.If I had a heavier machine I would definatly have chocked it.Hope this helps !!!Regards Sam

[birdy]

If the machine is anywhere near the correct angle of the dangle, the stick/torque tube will be centered anyway.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[asra]

BirdyFor once I disagree with you.The reason the torque tube wants to lift during hanging (Head tilt forward)is due to the design of the standard semirigid teeter-head system.The bearing block and tower plates are mounted to the torque tube by the centre spindle bolt, which is bolted behind the fore/aft pivot bolt.This causes a small amount of leverage regardless of the dangle Regards Sam.Image Insert: 40.53

[asra]

The (angle of the) dangle...come on guys, my kids read this stuff!jm

[asra]

Sam I agree totally with you on this ... I have tried to explain it like you have but had no results except them all thinking I been drinking too much ! hehehehehe my rotor head is set up alot like yours is ...with that zig zag of what would be the lifting force.... and there is NO way in gods green earth that the stick can do anything but go full foward when in the haing test .... Now How you set the proper stick position I have no idea because everyone just says it will ! !! and don't realise it cannot be anyway but full foward ! .... So .... I guess get it where you think it should be thats what I did ????? not much help I know ! with your Pic there perhaps we both will learn from someone that knows what we're dealing with ! C ya ! Bob " Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[Greg Mitchell]

Looks like a Monarch/Butterfly head arrangement.I'm still struggling with this whole head plate issue, centering of the stick and different weight pilots ect.www.thebutterflyllc.com

[asra]

When gyros are siting on the ground you should have 20deg back tilt posable this is when we set the stick & the hang test is just to confirm nose down attitude

[birdy]

Rito Sam, you clear for a free hit[B)][ and make it hard[xx(]].I forgot to mention the trim spring didn't I.[]If the spring is tensioned for cruise, THEN it'll hang centered.Which BTW, is an easy way to preset your trim spring before testing.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[asra]

Sorry Birdy.Didn't mean to pull any punches.We are all here to learn and help others, in the same way others helped us.I even learnt something from your last post. I must say my machine did require trim spring tensioning, during its first flight.Will have to try setting it during hanging next time, next machine.Greg, yes the pic is of a monarch rotor head.why are you struggling with the whole head plate issue. What don't you understand ?Regards Sam.

[asra]

Birdy ... You o'l buzzard ! How ya doin ? Hope you ain't landed on any cows lately ! When I tried to adjust my trim spring to center the stick it was so strong that I had to double the spring ... when I finally got the trim spring adjusted to where the Stick was centered between the throws of the joystick ... the tension was about 25lbs on the stick pulling back all the time ! ...except when in the haing test ofcorse..... I couldn't even tie the stick foward anymore the tension was so strong..... so needless to say I un did it .and later took off the trim spring adjuster completely to save weight .... Are you guys still maintaining that adjusting the stick to center position is able to be done in a haing test with this kind of a rotor head ???if so I'm missing something , or your missing something somewhere along the line ! ....no realy ! C ya !Bob......" Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[Tim]

Sam, the line of force through the head is a lot closer to the pitch pivot than your diagram suggests. The gyro is hanging nose down at 9 degrees and the line of force drops vertically from the teeter bolt. In some cases (eg. very tall towers) it may even pass through the pitch pivot making the hang test stick force neutral. In most cases though it is just behind the pitch pivot, making the resulting rotor lift force (250kg plus) easy to cancel out with a comparatively light spring.Tim McClure

[asra]

Tim do you mean the pitch pivot?Question for everyone. The torque tube offset can vary from manufacturer to manufacturer. Bensen 1" (25mm), Aircommand, 3/4"(19mm), Raf 3/4"(19mm), I think Gerry Goodwin 5/8"(16mm), Rosco I think is either 16 or 18mm.The trim spring requirements can change quite dramatically from one design of rotor to another on the same machine, all else being equal, i.e rotor diameter etc.Why is it so?Aussie Paul. []www.firebirdgyros.com