Piper1

Hi All,
just setting up a old version of the Fibre Classis f86 Sabre and wondered if anybody could help with the C of G position

Regards,

Piper1

ravill

My Feedback: (11)

If no one can help, most F-86's have the CG about 1.5-2 inch infront of the mains. This is ofcourse VERY dependant on how big your 86 is. But it is a start.

Good luck!

Here is BVM's CG for his 86's.

http://bvmjets.com/Pages/CG.htm

This maybe presumptious of me, but make sure you er on the nose heavy side vs the tail heavy side!

Turbulence

My Feedback: (76)

Shui had an interesting way of doing CG on the BV F-86, he would sit it the tail on the floor and move the CG until to nose gear would bearly pull the nose gear back down to the floor. I had TAM check it that way on his Redbull one back in the day (That Jet Rally next to the lake in Central Cali, Oakdale?) and it was spot on. Of course that was for a BV version and it's smaller than the Fiber Classics.

Turbulence

Piper1

Thank you Guys, all good stuff, much appreciated, will need to see how it compares to BV version etc. Unless of course I get Fibre Classics information !

Chris Smith

My Feedback: (2)

The Sabre has a 35 degree sweep at the 25% chord. Use the mean chord calculation at 25% and draw it perpendicular to the fuselage at the wing root.
Don't guess at the CG. Use the calculation. It's just math.

Piper1

Thanks Chris, fair comment, will do the maths and see what I come up with.

Jgwright

I am sure I saw a post by John Mac which has disappeared, where he said the CG is on the innermost point of the mains doors. This is what was given in the FC instructions on mine and that was how we flew it. We found this was the correct CG. No need to guess or calculate. There are some old threads that I cannot find now with more info on the plane. If this is the first flight you should consider beefing up the wing joining rod as I found it flexed. I used a close fitting carbon tube over the width of the fuselage. The retracts let down a superb plane, but it is an old design now. We had to go inverted to get them to go up. You may well be able to find better retracts.

John

Piper1

Thank you John,
will check out the wing joining rod. Good advise. This plane has not flown for a number of years !
so refitting with new gear, retaracts etc. Hopefully get it back to its former glory.

John.

Jgwright

Just to make it clear the doors where they are close together have a point to them. This is the CG position. The manual says you can go 15mm ahead of this for first flight if desired. Good luck with the refit. Mine was an old part completed model and I had to renew most of the servos with modern ones as the old ones were very prone to damaging the gears with shocks. I found the epoxy that held the Robart pin hinges in place had turned yellow and denatured. Some pulled out easily so I removed the lot and re-glued them.

John

Piper1

Thank you John for the clarification and the note about the hinges, much appreciated.
John

JohnMac

Hi John,
You are right, I did post. No idea where it went?
John