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Old Nov 08, 2012, 09:31 PM
R.C. Designs - I fab. things
DrlSgt's Avatar
United States, MI, Sterling Heights
Joined Oct 2009
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Help!
Airtronics Grand Esprit Dimensions

I'm looking at the Plan sheet and the tail boom dimensions in the top view are different from the side view. I'm getting a quote for a custom carbon boom and I need to give the supplier a size.

The top view shows the boom as:
33.500 x 1.200 x .350

The side view shows the boom as:
33.500 x 1.200 x .700

the plans inply that the boom has flatened sides starting near the center and running to the tail end.

Can someone give me the exact dimensions as supplied with the kits?

Also, there are several holes in the tail end for mounting the tail planes and as such are really bad for a carbon boom. Should I be using a FG boom instead reinforced with some carbon?

Thanks
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Old Nov 08, 2012, 11:13 PM
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Joined Jan 2007
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I would repost this over on the thermal forum. I'm sure someone over there would know the answer. Larry Jolly is over there a bit and used to work for Airtronic's during that era.
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Old Nov 08, 2012, 11:46 PM
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John Cole's Avatar
United States, CA, Santa Rosa
Joined Jun 2001
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My GE boom is a 33.75" tube, 1.2" tapering to .75". The boom is a tapered flat-wrap made of fiberglass and epoxy resin. The boom ends at the stab TE, and there is a balsa extension several inches long stuck on the end. This balsa extension also has a ply skid bonded to it. You could use carbon, no problem and much lighter-stronger, etc. The boom has no holes drilled for the 'v' tail, it is mounted above the boom on a balsa-ply bed.
There are two holes drilled about 1.5" from the tail end for the pushrods to exit. Hope this helps!
John
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Last edited by John Cole; Nov 09, 2012 at 12:08 AM.
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Old Nov 09, 2012, 06:08 AM
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United States, FL, Shalimar
Joined Jan 2009
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You will have no problem with the removable tail or control rod holes at the end of the boom, there's plenty of ply and balsa on the tail mount to make up for any weakness in the carbon if any.

Quote:
Originally Posted by DrlSgt View Post
I'm looking at the Plan sheet and the tail boom dimensions in the top view are different from the side view. I'm getting a quote for a custom carbon boom and I need to give the supplier a size.

The top view shows the boom as:
33.500 x 1.200 x .350

The side view shows the boom as:
33.500 x 1.200 x .700

the plans inply that the boom has flatened sides starting near the center and running to the tail end.

Can someone give me the exact dimensions as supplied with the kits?

Also, there are several holes in the tail end for mounting the tail planes and as such are really bad for a carbon boom. Should I be using a FG boom instead reinforced with some carbon?

Thanks
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Old Nov 09, 2012, 07:28 AM
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John Cole's Avatar
United States, CA, Santa Rosa
Joined Jun 2001
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Edit: In looking at the stab mount, holes are drilled for the stab screws as well.

John
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Old Nov 09, 2012, 06:22 PM
R.C. Designs - I fab. things
DrlSgt's Avatar
United States, MI, Sterling Heights
Joined Oct 2009
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Thank you very much for the replies. The info is very helpful.
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Old Nov 10, 2012, 02:45 PM
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John Cole's Avatar
United States, CA, Santa Rosa
Joined Jun 2001
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You are welcome, let me know if you need any more information. I have resources available for this model (2 completed from old kits, and an old Airtronics kit)
John
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Old Nov 11, 2012, 02:02 AM
Balsa breaks better
Thermaler's Avatar
Buchanan Mi
Joined Apr 2005
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Look at cross section D-D just above the TE on the side view, it should give you the answers to your dimension questions.
The glass booms on my Super and Grand Esprits have survived several crashes that have required the front of the fuselage to be replaced but the V-tail mounts are from the orginal builds.
Carbon should hold up better than the glass.

Joe
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