Fuselage jig

[DaveMackey]

Hello.

I'm from Australia and currently just starting to build a kitfox super sport 7 with a rotec radial. So far I have constructed the stabiliser and the elevator and one wing. I'm about to attach one wing to the fuselage for a dimesional check of the wash out, dihedral and sweep and need to find a simple way of levelling off the fuselage so it sits rigid on the garage floor when I attach the wing.

I'm new to this forum and need a little advice re setting up a jig to the bottom of the fuselage. Any photos would be good.

I also hope I'm in the right place of this forum to ask the question.

[Dave S]

Hi Dave, (BTW - great first name)

There about a thousand ways to do this. I have attached a couple photos for examples.

2196 is early on when I was fitting the wings and needing to level the fuselage. I made a cheap/low tech carriage to bolt under the gear pads - this was mostly for wheeling the fuselage around; and, then when I needed to level things up, I simply used a combination of whatever boxes/wood blocks/sandbags on the tailskid to get it to level. For lateral leveling - plywood pieces of various thicknesses in combination under the correct carriage wheel did the job.

2636 is later on when I had the gear on. - the tail dolly is an improvisation to move the plane in and out of the garage with the wings folded. There is a reason for the intermediate height of the improvised tail dolly - high enough to get the prop under the garage door and low enough to get the tail in. Again - when I needed to level it up for various purposes - just used whatever wood blocks, etc which would be the right height. For lateral leveling - plywood pieces of various thicknesses in combination under the correct main wheel was used.

Hope that helps some - there really isn't a specific jig for leveling - but a person can improvise many ways to get it - low tech and simple works.:)

The dirt bags:o in the cockpit were for balancing before the engine was attached.

Sincerely,

Dave S
KF7 Trigear
912ULS Warp

[Dave S]

Dave - I should have mentioned - the wheels on the carriage are hard material - not pneumatic so there was no give/spring there.

DS

[CDE2FLY]

Dave's right - there's lots of ways to get the fuse leveled and geometry dialed in. I used a ratchet strap hooked from the ceiling of the work shop to the hand hold near the rear of the fuse which allowed very precise adjustments in "pitch" by making small adjustments to the ratchet strap. I adjusted the "roll" axis buy deflating the tires 1/2 way and adding tire pressure to either side as needed to level the wings. One tool that's invaluable during this process is a "smart level" (see link below). It's not cheap but it's a real time saver and makes it easy to get everything aligned. From first flight to the end of my flight test phase, the sum total of adjustment to the rigging of the airplane was turning one of the lift strut rod end bearings one turn. I doubt it would have been so close without the smart level.

http://www.lascolaser.com/product/M-D-SmartTool-Electronic-Module-with-case-Smart-Tool-Digital-Module--Degrees-Percent-or-Pitch_Qitem92346.html

[DaveMackey]

Thanks guys for your prompt replies. I thought it was night time over there. Its my first time on a forum such as this and if I get this type of
quick service, I'll be back a lot. No one around here is building anything
remotely similiar to a radial engine kitfox so its great to have this type of help. The photos are great.

DaveM

[Geowitz]

Maybe this goes without saying, but one thing I noticed... You said you were just putting on one wing. Be careful and make sure you anchor the fuse because it will be enough weight on one side to tip.

[Northof49]

Hi Dave,

This is how I jigged my fuselage for the IV.

I can move it on any unlevel surface and level it in a matter of minutes.

[DaveMackey]

Maybe this goes without saying, but one thing I noticed... You said you were just putting on one wing. Be careful and make sure you anchor the fuse because it will be enough weight on one side to tip.

Thanks for that I will finish the second wing before I jig the whole thing.
DaveM

[DaveMackey]

Hi Dave,

This is how I jigged my fuselage for the IV.

I can move it on any unlevel surface and level it in a matter of minutes.

Love the scissor jacks, great idea.

DaveM

[DaveMackey]

Hi Dave, (BTW - great first name)

There about a thousand ways to do this. I have attached a couple photos for examples.

2196 is early on when I was fitting the wings and needing to level the fuselage. I made a cheap/low tech carriage to bolt under the gear pads - this was mostly for wheeling the fuselage around; and, then when I needed to level things up, I simply used a combination of whatever boxes/wood blocks/sandbags on the tailskid to get it to level. For lateral leveling - plywood pieces of various thicknesses in combination under the correct carriage wheel did the job.

2636 is later on when I had the gear on. - the tail dolly is an improvisation to move the plane in and out of the garage with the wings folded. There is a reason for the intermediate height of the improvised tail dolly - high enough to get the prop under the garage door and low enough to get the tail in. Again - when I needed to level it up for various purposes - just used whatever wood blocks, etc which would be the right height. For lateral leveling - plywood pieces of various thicknesses in combination under the correct main wheel was used.

Hope that helps some - there really isn't a specific jig for leveling - but a person can improvise many ways to get it - low tech and simple works.:)

The dirt bags:o in the cockpit were for balancing before the engine was attached.

Sincerely,

Dave S
KF7 Trigear
912ULS Warp


Thanks Dave thats a nice cheap way of doing it. I was thinking along the same lines. Would you also be able to help me with this? In the wing installation instructions, it refers to the making of a temporary lift strut brace 36 1/2 inches long from 2X4 board. Apparently when you install the wing this assists. Do you have any photos of this process. Its on page 14 Section C of my instructions for Wing Installation Preparation. There's no picture and I'm not quite sure where this temporary strut is installed.

DaveM

[Geowitz]

Thanks for that I will finish the second wing before I jig the whole thing.
DaveM

Yeah, you need both wings to do the sweep anyways and it's best to do them both at the same time so you can ensure all the measurements match on each side before you make anything permanent.

For the strut supports I just used a 1x2 and duct taped it onto the spar and strut ends. It's just there to keep the strut from falling beyond the rod end's safe travel without ripping the rod end off. You attach the spars to the fuse while a friend is holding the end of the wing. Then attach the strut to the fuse and take the brace out. Here is a pic...

[Dave S]

DaveM,

I checked my photos and did not have any of this jig; however,Geowitz's photo of how he secured the lift strut, and the explanation is similar.

I think the dimension shown in the manual is for locating the wood support close to the attach point of the lift strut and near the root end of the spar. If a person locates the wood support further up the strut and spar - it has to be shorter than the dimension in the manual by some amount. The idea is to locate the lower end of the lift strut so it is easy to slide on the fuselage fitting while protecting the rod ends from stress.

I think the instruction to use a 2x4 in the manual is a matter of a convenient size of material most of us have laying around - either a 2x2 or 1x2 is certainly sturdy enough for the job.

If I recall - I used a 2X4 and notched the lower end to go over the lift strut then duct taped the whole business together.

Cheers,

Dave S

[DaveMackey]

Yeah, you need both wings to do the sweep anyways and it's best to do them both at the same time so you can ensure all the measurements match on each side before you make anything permanent.

For the strut supports I just used a 1x2 and duct taped it onto the spar and strut ends. It's just there to keep the strut from falling beyond the rod end's safe travel without ripping the rod end off. You attach the spars to the fuse while a friend is holding the end of the wing. Then attach the strut to the fuse and take the brace out. Here is a pic...


Thanks for that I was trying to visualise the concept but the instructions did not have a photo.

DaveM