RunRyder - Gohbee 90 Pitchy FFF

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Gohbee Aviation Stinger 30-90 > Gohbee 90 Pitchy FFF

TDriver
Veteran
Location: Portage IN

I have a 90 and it is so pitchy in FFF that i hate to even fly it .Im running the stock paddles they look in line .Things i have tryed more expo less expo no help turn the DR`s down didnt help all the links i checked none seem to be tight .Im lost with this thing ..Help Please

OK i was looking tonight and found alot of slop in the head i made a short video .Before i did this i got my NIB gohbee 50 down and there is no slop in it .So is this normal for the 90`s? i know it kindy hard to see but its moving all over the place ..When you do this the swash dont move. I been fighting this from day one it only has 4 flights on it ...

http://www.youtube.com/watch?v=ybut78laG3Q

05-11-2007 Over year old.

JRjoe
Elite Veteran
Location: Portage, IN

Hmmmmm...........

JRjoe

05-11-2007 Over year old.

Yug
rrProfessor
Location: UK. Herts

First things first, get rid of that slop

You say it's pitchy, which way. Does it balloon up or pitch down in FF ?
If its ballooning up then you need more flybar authority, ie faster paddles, longer flybar or increase the flybar ratio. If its pitching down, you need to do the opposite and reduce the flybar's authority.

05-11-2007 Over year old.

Itsindilas
Veteran
Location: Greece-Athens

Which paddles you use?

05-11-2007 Over year old.

JRjoe
Elite Veteran
Location: Portage, IN

I was there yesterday and saw this thing fly. It's very pitchy in the elevator, mostly seemd to pitch down. Didn't seem to be that bad when moving slow in FF. Seemed overly sensitive in Fast FF......
He has the stock paddles on it.....

JRjoe

05-11-2007 Over year old.

Itsindilas
Veteran
Location: Greece-Athens

This a typical behavior of unstable paddle setup. That's the reason I ask for paddle choice. Usually, very sharp paddles (paddle's airfoil) with an too front attaching point, leads heli to such a behavior during speed increase. It has to with Aerodynamic Center of Pressure of the paddles, as it changes position proportionally to the speed.
Another parameter, that contributes to this, is the existing wearing, and I am talking about wearing regarding any linkage that has to do with flybar.

05-11-2007 Over year old.

JRjoe
Elite Veteran
Location: Portage, IN

His flybar seemed to be made of a kinda softer metal. Could the flybar be flexing and causing this???? Just a thought....

JRjoe

05-11-2007 Over year old.

Itsindilas
Veteran
Location: Greece-Athens

I cant't answer this. In case it bends, and while it bends it gives an angle of attack, then YES. But, in case it bends but its angle with air doesn't changes, the NO.

05-11-2007 Over year old.

FLYINFOOL
Veteran
Location: Cudahy, WI

Also check the CG of the heli.
It should be as close to the mainshaft as you can get it.
Do not check CG by lifting at the flybar. It does not work well.
Hold the heli by the head with the mainshaft parallel to the floor this will give you the most accurate CG. I set my CG with a half tank of fuel.

Jeff Borowski
Gohbee Field Rep
0133TD

05-11-2007 Over year old.

HOMEPAGE

TDriver
Veteran
Location: Portage IN

Ok i was checking the CG by the fly bar ,But i just checked it holding by the head and it seems fine ..Im not sure how to get the slop out the washout base seems tohave alot of slop on the main shaft and flybar control levers have alot of slop where the little pins are that go to the swash...

05-11-2007 Over year old.

Yug
rrProfessor
Location: UK. Herts

Perhaps they're just warn out. I have to periodically replace washout hubs for that reason.

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

This is only 4 flights old!!!!!!!

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

Quote
Perhaps they're just warn out. I have to periodically replace washout hubs for that reason

If that is the case i got a Gohbee 90 for sale...

05-11-2007 Over year old.

Yug
rrProfessor
Location: UK. Herts

4 flights

There shouldn't be anywhere near the amount of slop your getting. Time to sit down with a beer and have a close considerate inspection.

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

I have looked and looked at it that is all i can find (the slop) you can hold the paddles and move them up and down id say a good 5mm and the swash dont move...

05-11-2007 Over year old.

TYREE
Veteran
Location: Sonoma county

Racer......

Have you called David at Gohbee?
If not give him a call....he would be more than happy to help you
trouble shoot your problem.

05-11-2007 Over year old.

Yug
rrProfessor
Location: UK. Herts

I think what's happening, is the washout hub is rocking on the shaft because it's a loose fit. Try holding the hub firm and then see if the slop has been reduced.

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

Quote
I think what's happening, is the washout hub is rocking on the shaft because it's a loose fit. Try holding the hub firm and then see if the slop has been reduced.

If you do that it cuts the slop about in half..the washout hub is loose on the shaft.

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

Thanks for the help guys ill try and give Dave a call and see what he has to say ...

05-11-2007 Over year old.

TDriver
Veteran
Location: Portage IN

Just got off the phone with Dave he is sending me a new washout set i hope that fixes it ..

05-11-2007 Over year old.

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Gohbee Aviation Stinger 30-90 > Gohbee 90 Pitchy FFF

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