Why my gyro didn't want to fly

dabkb2

Dave Bacon
Joined
Sep 26, 2005
Messages
2,787
Location
Vista, Ca
Aircraft
Sport Copter Vortex 582, 2 KB2 90Mac KB3 582
Total Flight Time
529 hours
I went flying my KB3 this weekend at El Mirage for the first time in awhile. I made some changes over the winter, a bracket on the tail had cracked and I put some bigger tires on. I did a good preflight and I thought it was ready to fly.

I taxi out prorated and started off and it did not want to rotate onto the mains, after about a half mile it finally rocked back on the mains. I was confused why it took so long to rotate so I balanced for awhile and it was all good so I took off and it flew great. After the flight Pete a gyro pilot said my gyro looked like the tail was too far in the air when I was taxing back. I mentioned that it took a long time to get off the ground. We came to the conclusion that by adding the bigger tires it changed the angle of the gyro, probably 2 or 3 degrees. Not a big deal once it is in the air, but 2 to 3 degrees less AOA made a big difference on take off.

I will probably put the small(4") tires back on. I like the way the 6" tires handle the dirt better, but I would have to change the axle to go with them.

Little thing mean alot.
 
That would work also, as long as the keel is level, it will have the right AOA
 
I bought this same type of discussion up a long time ago ! It was about how the gyro sat on the ground & the angle of the rotor blades.

Noone had a thing to say ....but I thought I was on the right track !

I will see if I can find that post.

OK ...there were some responces. My brainstorming began at post 27.

http://www.rotaryforum.com/forum/showthread.php?t=3672&page=2

See if this relates to you !

Hey !!! Whatever became of Udi ???? Never mind.....he's still around !
 
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I think you got it right Chris,
 
That is a new thought, and a damm good one too, I think that is the answer that I am looking for, you da man, Mark
 
I will have to shorten the axle to mast support, but that is an easy fix
 
Or you could put the axle on top instead of bottom

Do you think the 2, 1/4 bolts will be strong enough to carry the load on a hard landing?
 
Hard landings

Hard landings

I have a video of someone flying a gyro that looks a lot like your work machine doing a hard landing at some nats a few years ago.
Not sure who was flying, but he was an ugly basted though.

Graeme.
 
Do you think the 2, 1/4 bolts will be strong enough to carry the load on a hard landing?

Dave, the major landing loads are taken by the mast-to-axle struts.

Bones sez:
Who does hard landings ???

If ya kant lan rite, gitcha one uv them thar G-Force elephant trap lookin' contraptions! Then ya don't hafta land, ya jes drop it, or fly it into the ground!:D:D
 
I have a video of someone flying a gyro that looks a lot like your work machine doing a hard landing at some nats a few years ago.
Not sure who was flying, but he was an ugly basted though.

Graeme.

Yeah i know i gots to have a few words with Birdy sbout that, it never been the same since :flame:
A** hole :first: atleast my machine still flying :argue::blabla::blabla:
 
Do you think the 2, 1/4 bolts will be strong enough to carry the load on a hard landing?

Sorry,
I just read your post Dave.
Actually there are 4 1/4in bolts that attach the axle on my gyro. I use a spacer under the axle to help distribute the load and keep the bolts from tearing through the tubing. I weight 250 now, I flew 22ft rotors as long as I could, so I have seen some hard landings. I fly 23 now, the landings are a little softer, but not pretty, like yours.:yo:

Dave,
think about this. The rotor head towers are held on by 2 1/4 in bolts and if you look closer, they are held on by the threads of the the 2 1/4 in bolts because on the Bensen head they are in tention not shear. But yes, I do think they are ok. Chuck or Doug can do the math.
 
Mark, I think with the axle to mast supports and the 2 bolts it will be ok. I hope to get er done this weekend, I will take pics
 
This worked good, I gained 4" by putting the axle on top of the keel. I need bigger tires on the mains to get the right rockback angel.
 

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Dave,
What size prop are you turning, I was referring to the axle spindle , sorry.
Also Dave a small piece of 2 in alum on top or your axle will do a lot to keep your axle bolts from collasping your tube over a period of time.
 
Mark, I have a 60" IVO prop. I have the stock KB3 spindels, so I can't put the spindels on top of the axle because of the bent axle they have a bend to the spindel.
 
Dave,
If the top of the 2x2 axle is the same angle as the bottom of it why wouldn't it work to locate them to the top? Maybe we need to see a closeup photo of the way a spindel is attached.
 
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