RonL

[RonL]

Hello....I'm not exactly new to Bearhawk building. I completed an LSA earlier this year (2017) and have purchased a tubing kit for a Patrol. I'm 76 yrs. old and have been building & flying homebuilt aircraft since the early '80's. I think the Patrol will be my ninth experimental. I can follow plans and instructions fairly well, but when I have doubts I like to ask other builders how they solved various problems. Mark Goldberg highly recommends this venue, so I'm going to try it. I'll post questions soon.

[Chewie]

Welcome aboard Ron! That's an impressive building resume.
Where are you located?

[Bdflies]

Hi Ron! Glad you finally joined in. Folks, Ron is one of us South Louisiana guys. He's built and flown some gorgeous airplanes, through the years. I suppose y'all thought he mentioned his age, to extract an extra bit of kindness. Don't fall for it! Ron is a building machine and will flat amaze you, seeing how much he gets done! I've attached a picture of his LSA.

Bill

[jaredyates]

We need a calendar picture of this LSA! And maybe an article in the Beartracks please!

[RonL]

Here's the question I have right now. The tubing kit has pre bent lower longerons that are spliced in two places. The plans show a flat layout with a total length of 107.5 inches point A to tail post. While jigging up the floor component, the rise at the tail post causes the tail post to move toward point A somewhat, effectively shortening the fuselage. If I try to keep the plan length at 107.5 and raise the tail as per fuselage side layout, the longerons come out of the rear splices. You can't tack weld the floor frame in the flat config. because of the pre bent logerons! Has anyone worked it out?

[Mark Goldberg]

Ron called me with this question about the tubing lay out using the Patrol tubing package. I am not really able to help him since my knowledge/experience is extremely limited (non existent) when it comes to working with the tubing package. You guys who have experience with the Patrol tubing package - please give Ron some advice.

Ron - that is the first picture I have seen of your LSA. Very nice. Beautiful. Mark

[BTAZ]

Some thoughts.....

Did you tack together the top already?

Might want to suspend it in place and tie the top/bottom longerons together with the tail post set vertical and at the proper distance apart and see what you get.

Or are you saying if you do that and set the correct tail to firewall distance there isn't enough length left in the lower longerons to make the splice?

Are you accounting for the plans dimensions being tube Cl to Cl?

I built my LSA using one of the first of Mark's tubing kits and everything fit great, but the lower longerons are one piece so didn't have this particular challenge.

Not sure if you have seen my log, but the first part covers how I approached things.

https://www.dropbox.com/s/p9v1iettu4txitn/LSA%20fuselage.pdf?dl=0

[sbmurphey]

Hi Ron and Welcome. I feel inadequate when stacking my building time up against your impressive resume. However, I did use the tubing kit for my LSA. I understand there are a couple items different with the Patrol. But the technique could likely be applied. I used the flat layout and drew it on my build table for the top structure. When I got to the bottom layout, I spent a long time looking at the plans and had the same questions you mentioned above.

I worried it to death and final started laying out the tubing with the available clues from the plans. The attached pictures show where I mounted the tail post plumb to the table via a temporary extension made out of scrap tubing and about 2 turns of electrical tape to take up the slack between the tubes. Each fuselage station elevation was scaled from the center line on the profile view. I cut blocks to the proper diminution to off set the tubes at each location from the table. To cross check this, I scaled the profile view for each cross tube on my table center line. This line was used to set the blocks on the table. From tail post to firewall, it measured within an 1/8" of the my scaled value. Figured that was close enough and with in the margin of error for a 10:1 scale drawing. Started tacking the structure together like a 3d puzzle.

[lsa140]

Welcome Ron! I found quite a few small irregularities between the fit of the LSA tubing kit and the dimensions listed on the plans. My longerons for example varied in length around 1/8" from the left to right sides. Either my firewall wasn't square or the tail post was off center. My firewall tubing was the same way; I couldn't get the provided tubing to dimensionally line up with the plans. This is the challenge of building from a hand build tubing kit... what do you favor? Plans or where the tubing wants to fit together? If you modify the tubing in the kit it can throw out alignment of other tubes. The best advice I can give you is to refrain from tacking the lower tubing and to play with where it fits together the best. There is going to be some small variation from plans. For example tube T17 (T18 on the Patrol plans - tail spring socket doubler) was 1/2" shorter than the plan dimension in my kit. The tubing is hand notched to fit a hand built jig. It isn't a CNC notched kit produced from an exact 3D model of the design.

I drilled oversized holes in my blocks and placed a fender washer under the screw head. This allowed tubing adjustment without backing the screw out and worked very well. I initially placed the blocking on plan location and then floated everything around a little until it was close to plans and gave the best fit.

All the best,
Craig