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7/9 fuselage rotisserie

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panheadmark

Member
I just rolled a big fat one last Saturday, Yeah! :p I welded up stands for a rotisserie and am wondering if the prepunched holes in the firewall for the engine mount are accurate enough to go ahead and drill. I was thinking about drilling 5/16" holes to mount the rotisserie which then could be enlarged later for the engine mount.
I haven't climbed in, sat down and made engine noises yet but that day's coming!
 
panheadmark said:
I just rolled a big fat one last Saturday, Yeah! :p I welded up stands for a rotisserie and am wondering if the prepunched holes in the firewall for the engine mount are accurate enough to go ahead and drill. I was thinking about drilling 5/16" holes to mount the rotisserie which then could be enlarged later for the engine mount.
I haven't climbed in, sat down and made engine noises yet but that day's coming!
Click to expand...

Hello Mark.

I'm on the road right now but I'll be home the first of next week. I have a rotisserie that was given to me by a -7 builder. An IO-360 was mounted to the nose of his -7. I will measure the bolt holes and let you know what size they are. However, and this is important, I don't think all engine mounts are created equal. Bolt sizes probably vary based on the amount of weight the engine mount must support - I just don't know.
 
Pre-punched Firewall

Don't touch that drill! You might get lucky, but my 7A firewall/mount holes were not nearly close enough to skip match drilling.
 
Rotisserie

OK then.......my finish kit is still about a month from arriving and I've got an itchy trigger finger on my drill.... How have other people been mounting their rotisseries to the firewall??? The only other holes that are open right now are the ones for rivets that are around the cutout. Don't like the idea nor will I hang the thing using clecos in those holes.

Mark Erickson
Minnetonka, MN
RV9A 91317
 
I just drilled my motor mount holes and you really need to match drill the holes with the motor mount, mainly due to the angle of the mount holes.

I started the hole with a 3/16" colbolt drill in one upper corner of the firewall and then also drilled the left upper hole from the firewall hole. Then I attached the motor mount to those holes with AN3 bolts. This allowed me to Match drill the other holes & install the AN4 bolts as i went.

I found that free drilling the upper holes worked because the later 3/8" final hole took care of the mismatch for the incorrect angle of the free drilled holes. I do not believe if you use a 5/16"" free drill that you will be able to cover the freedrill mismatch.

I would use the rotissary, but use 3/8" holes & matchdrill with the motor mount as above.

You do not want the motor mount falling off.
 
I have a rotisserie stand I bought from another builder but have decided not to use it for two reasons: It requires drilling/mounting at the motor mount locations and I do not yet have the mount for match-drilling the holes. The second reason is the instructions that I have for installing the stand stipulate NOT INTENDED TO HOLD THE WEIGHT OF A PERSON IN THE FUSELAGE.

I will probably offer it for sale but shipping the beast would be problematic.
 
Need Rotisserie in Northern California

Does anyone have a rotisserie they're no longer using, within driving distance of Stockton, CA?
 
I'll wait

Thanks for replying, I will wait untill my engine mount gets here before drilling the holes, there are plenty of things I can do in the mean time. Common sense will tell you not to climb in the fuselage unless it's well supported.

Mark Erickson
Minnetonka, MN.
RV9A 91317
 
Just so future readers don't miss this...

The holes in the firewall are NOT accurate enough to pre-drill w/o the engine mount, at lest they weren't in my case.

I drilled one hole to size, bolted the mount in place, leveled it, then used it to start drilling the hole for the second bolt. Took it off, finished drilling the second hole to size, put it back on w/ two bolts, started drilling the third hole, took it off, finished drilled the third hole, put it back on with three bolts, started drilling the fourth hole, etc. I did not want to drill the holes to final size while using the engine mount as a drill guide as I was afraid I would wallow out the bolt holes in the engine mount.

When I finally bolted it up, I used large area washers as shims for the two center bolts, one on each side, to help spread the load.
 
A spinner!

Finish kit arrived Friday, engine mount fitted and drilled on Saturday, and up on the rotisserie yesterday.:) The pre-drilled holes in the firewall were off by about a half a hole or less. Having it up and being able to spin it any way I want sure is a wonderful thing! I'm in heven!:p

Mark Erickson
Minnetonka, MN
9A #1317
 
You can hold the rotissery with the holes on the side of the fuselage

I Pan on using the rotisserie, and using the many holes that are on the fuselage skin protruding out from the firewall.
 
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