Top Fuse Stringers

[Wes Ragle]

Guys,

I am about to pin the fuse top stringers on a four place QB. The stringers are the aluminum stringers supplied by Bearhawk Aircraft/Avipro. Having had no experience with tube and fabric, I can't visualize exactly where to pin the stringers in the most aft saddle. The one just forward of vertical stabilizer. Should the stringers be flush with the top of that saddle for best covering results?

Thanks,

Wes

[jaredyates]

Wes, in this photo I'm using different stringers, but I think the concept is the same. Is this where you are working with?

http://jaredyates.com/bearhawk/wp-content/uploads/2013/01/P1020888.jpg

[Mark Goldberg]

Wes, you are right. It is the "top" or the outside which you see. The stringers need to be flush with the top. I have terminated those stringers into the little U channel piece two ways.

I have brought the two stringers together inside the the little U channel. I have also bent the sides of the U channel out and connected the stringers on the outside. Mark

[Wes Ragle]

Hi,

Yes Jared, that's the one. It just didn't look like it would make a smooth transition to the vertical. I'm thinking too much about something I know nothing about. Flush with the top it is.

And I see what you mean Mark. Maybe it would flow a little better with the stringers on the sides of the channel.

Thanks a lot guys.

Wes

[Zzz]

Wes, in this photo I'm using different stringers, but I think the concept is the same. Is this where you are working with?
http://jaredyates.com/bearhawk/wp-co...1/P1020888.jpg

What did your fabric turn out like at the ELT antenna mount? Is there a visible step from the alum plate? Curious why you decided to go above the stringer elevation.

[jaredyates]

Wes, is your concern that the stringers bend down too much? It occurred to me that since your stringers are taller than the ones I used, they are going to sit slightly higher at the next forward mounting point. Can you elaborate on what your concern was/is?

Zane, I think the fabric turned out fine. If you were looking for it, you could probably find a small transition. My main concern was with not getting the mounting plate too low, and thus having a dip where the antenna would be pulling the fabric down. Another option for this type of mount would be to bend the plate and put it between the stringers and flush with the top, but that seemed harder to get right. I had this one made in about 30 minutes, done and ready to get to work on something else.

[Wes Ragle]

[QUOTE=jaredyates;n9015]Wes, is your concern that the stringers bend down too much? It occurred to me that since your stringers are taller than the ones I used, they are going to sit slightly higher at the next forward mounting point. Can you elaborate on what your concern was/is?

Hi Jared,

I had read in the construction manual that the stringers along the side should "fall away" from the fabric as they end. I just don't have a feel for how the fabric is going to behave when it is shrunk. In my minds eye there would be a lump where the saddle/stringers end and the transition to the round tubing begins. Again, just lack of experience.

Thanks for the pic. I'm no longer worried.

Wes

[jaredyates]

I think you will want to apply that "fall away" strategy to the bottom two stringers where they end, since they kind of float in space. I think that comment comes from concern about chaffing if the loose end vibrates under the fabric. I gathered that anything with a rigid end, like those top stringers, will not have the chaffing concern. And as for experience, I'm right there with you, having only covered one airplane myself!

[Mark Moyle]

Here's my ELT mount....not the Bearhawk...it's the Pacer I crunched in December. Today fuselage is ready for paint.


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[Mark Moyle]

Here's my fall away version for aluminum hat stringer
Practice part


Installed

[marcusofcotton]

Nice Mark, I hadn't thought about using the safety wire to draw it down and stiffen a bit at the same time, thanks for posting up the pics.

Bet you're anxious to get back to Bearhawk progress!

Mark J

[Battson]

Hi Jared,

I had read in the construction manual that the stringers along the side should "fall away" from the fabric as they end. I just don't have a feel for how the fabric is going to behave when it is shrunk. In my minds eye there would be a lump where the saddle/stringers end and the transition to the round tubing begins. Again, just lack of experience.

Thanks for the pic. I'm no longer worried.

Wes

Wes - I filed mine down to create a smooth transition from the stringers to the tail former, after it was temporarily pinned, so I could file the steel and alloy together into a smooth shape.

You can see the result here, note I used a panel fabric method with a seam in that area:


I also filed the edges of all the stringers, per the manual [Big job].

[Mark Moyle]

Nice Mark, I hadn't thought about using the safety wire to draw it down and stiffen a bit at the same time, thanks for posting up the pics.

Bet you're anxious to get back to Bearhawk progress!

Mark J

Yup, bought this Pacer to gain flight experience before flying my Bearhawk.....in something that doesn't fly it's self...and possibly squirrelly.. Then I wrecked it...thought I was an idiot...until I tore the fabric off the busted right gear leg and discovered all the ancient cracks. The FAA let me off...no check ride. Hope to squirt paint on the fuselage in a few days....
Mark M.


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[marcusofcotton]

Good to hear you missed out on the expense,time, and bother of the 709 ride. 'Course I'm sure you didn't have much else to do anyway... ;>)

[Mark Moyle]

Ha....I've got a good grump-on. Spent this weekend trying to restore water to the community. Should have been a simple..pull the well pump pipe string and pump. Three men and a fat boy couldn't lift the pipe from the pitless adapter. Screwed an 1-1/2" pipe into the adapter...9' down. Nylon lifting strap, 510D John Deere....lift with the back hoe...stripped out the threads... Re threaded the pipe..lucked out..was able to force the pipe into the adapter. Lift again with a nylon strap while beating on the pipe with a three pound ham damner. It jumped 5 feet when it came loose. Discovered someone in the past had forced the adapter to seal by driving it together with a sledge hammer.....it busted off in the well casing. Parts should be in the morning to repair the system. The .....thing is. Have to excavate about ten feet of material. One foot of which be under the water table. Going to have some numb fingers....


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