Mitch

Many thanks to Peter Lovegrove for his excellent article in the latest gyro news.

Prior to flying my Butterfly after the Cooma event, I decided to ensure my rotor head system was set-up exactly right. I read the article several times and proceeded to action.

I believe it is important to note here, that not all hub blocks are the same. For instance my old original 1978 Benson Blades and Hub Bar have what appeared to me to be circular machined rebates into each side of the hub block. Upon discussing same with a number of people I was assured that each side of the block had been warn in by previous teeter bushes (tophats). This seems logical as they are not the same depth.

When I was advised to set my head up on Butterfly initially, the deal was to ensure a gap of 2.490" between inside faces of tophat teeter bushes. The distance between inside faces of towers 2.5".
To ensure this gap we were to make up shims of 6061-T6 from .0025" material and to place them each side of the towers between the teeter bushes and the thrust washers. They would require machining down to give the correct gap and tolerances. This may well have been the go on a hub block with no side rebates.

I have made up shims of same material one at 9 thou and the other at 14 thou that go between the inside faces of teeter towers and against the face of the hub block on both sides. Due to the different thickness, each face of the block and each shimm is marked, for correct placement. I now have about three thou float and the teeter bolt and block teeter on the bushes as required.

After flying for a couple of hours with two mates yesterday, I was very pleased at how smooth the whole system was. I had a look at the rotor head set-up on another gyro. We found it had no float at all. He advised me he has a slight two per rev through the stick. We reviewed the article and discussed the fact that he would need to shim inside faces also.

I would appreciate any further comment on this, it is so easy to get it wrong and I believe not fully understood or appreciated. The rebates in the hub block certainly caught me out. If it's not set-up correctly you can find the block sliding on the teeter bolt, causing excessive wear to bolt and block, ect.

Cheers,

Mitch.

Benson Blades.

I don't really know any different, because I soloed on Benson Blades but they drop out last few feet. My only comparison is to the two place trainers I have been in. They are all using new generation stuff and the flare is totally different to my Bensons, they don't hang on. I only mention this because it has been something like 6 weeks since I flew at Cooma. Saturday first landing was a gooden, because I flew her all the way in, no flare to speak of. Next landing I tried to hold her off a little and they let go and I dropped in. Almost like what has been described as what happens in a down wind landing. Look out! ops:

Bob

Verry interesting Post there Mitch !
I'm not sure exactly what it is you are talking about however ! but it is realy interesting!
My rotors and Hub bar are obviously set up alot diferently than what you described so it makes me wonder just what the heck ya got there ehhehehehehe !

are you talking about the side to side play at the teter bolt ? where the hub bar and teter towers can slide back and forth ?

or shimming the teter towers themselves ? ( doubt that )

my teter attachment for the hub bar is held appart by 2 teflon sheets rivited to the tower supports
once the teter bolt is snugged up ( tad over finger tight) its safty wired and your good to go , it can't slop back and forth ...

thank ya !

Bob.......

__________________
"My Momma' Told me the Impossable is only a little bit harder... You Know ... I do believe she is Right ! "

Mitch

Hey Bob,
Shortly after that post, I crashed.
Cheers
Mitch.

Bob

Mitch !
Ahh No biggy Mate ...happens to all of us now and again ...just glad you wern't hurt !

Have you seen the post on Gyrobee section on rotory wing forem ? a fella is setting up his gyro to take a parasail ! ... sounds like a neet option to me ....
I know it wouldn't be the same without a rotor ...but for a novis like me it may well be the way to go eh ? .... save my rotors till I know what I'm doing ! HAHAHAHHA !

I am tickeled every time I hear about a gyro crash and the person walks away with their bod intact, or just minor injuries .... to me that is better proof that gyros are safe than all the "REPORTS" in the world ! ... what has it been this year ...? how many crashes on all the forems ... say 6 or so .... and no deaths that i know of one back east last year died
... it just is refreshing that with all the wrincled up gyros the people usually walk away !
.... Any Way....
How you comeing on your Rebuild Mitch ?
I got mine all done but the rotor and prop already ! and would'a had that done already if i had the funds , but oh well !

haing in there Buddy !

Bob....

__________________
"My Momma' Told me the Impossable is only a little bit harder... You Know ... I do believe she is Right ! "

Mitch

Bob,
Really just starting and it is a complete rebuild.
Some of us are lucky to survive our own stupidity. Haven't seen the thread on the Bee, will track it down. You take care now Bob and good luck with the timber prop development.
Cheers,
Mitch

Bob

hehehe I KNOW how you feel ( blush ! )
Take care buddy !
c ya !
Bob....

__________________
"My Momma' Told me the Impossable is only a little bit harder... You Know ... I do believe she is Right ! "