What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Longeron template?

s10sakota

s10sakota

Well Known Member
The manual states to cut the longeron bend template from Drawing 17 and glue it to a piece or cardboard or something.

How did you guys do this? The template is about 4-5 feet long.

Did you use a thin piece of plywood? Did you have a 4 or 5 foot long piece of aluminum laying around? Any pics you could post of your template.

I'm looking for a way to make the template, without buying a 4 x8 sheet of playwood! (I wonder what would be the thinnest cut of plywood I could get?)

Thanks!
 
I didn't. Not wanting to butcher up the plans, I laid the sheet out flat on the 8' long work bench and bent the longerons to match. They turned out perfect.
 
Template

There's two. One one the 7 and one on the 7a sheet. Since I am building a 7a, I cut the template off the 7 sheet and cut a piece off one of the huge cardboards from the crates. Glued it on. Any solution will work but make sure your final check is with the part. I forgot the number but it's on the drawing with the longeron.
 
Hardboard

I glued mine on a sheet of Masonite hardboard. I went to Menards or Home Depot and bought a damaged piece cheap. Glued it on and cut it out.
 
I had one of the Vans cardboard shipping boxes that are long and wide and just used that with some contact cement. Worked just fine. Something a bit more stiff would be nice.
 
longeron bend

I found the template on my prints to be nowhere near close. I used the plate that rivets to the top of the longeron in the area of the bend to get the correct radius. I thought I would have to buy a new longeron because of the overbending. Fortunately, I removed what bend was needed and all is well.
 
Aluminum sheet

I got a piece of .062 aluminum from a local sheet metal shop, placed it under the plans and center punched through the plans to outline the curve. Joined the dots and cut out the template. Clamped my longerons back to back and used a bottle jack in a homemade press, with a hardwood shoe drilled for the bottle jack rod and slotted for the longerons. Worked great.
 
Like TruFlite, I used the F721-B deck pieces as templates for the outer edges of the longerons. That, coupled with the slotted jig that is advertised on here (can't remember the name now, will look it up and post later) that you put in a vise and squeeze the longeron between the two curved dies, made bending them two pieces of cake. Did the downward bend and twist per the instructions, that worked fine also.
 
I just laid the plans on the hangar floor and used them without any modification. I didn't want to destroy the plans by cutting them out.
 
Ya

I doubled sided taped them to a board, actually the wing crate turn on edge, and bent using the longeron dies. Came out great easily within a 1/32?. For the other side i turned the plans over, trace the shape using a french curve drafting tool, doubled taped to crate and bent away. NOt nearly as difficult as i imagined.
 
Speaking of bending longerons; anyone have the -7 bending dies they no longer need and can donate them to another-7 builder? I'll return them when finished...or pass them on to the next builder.

Much obliged.

(My apologies to the original poster for hi-jacking this thread...)
 
For the benefit of future builders, if you choose to use the F-721 deck piece as the template for the bend, make sure you position the piece at the correct location on the longeron or you may end up doing something like this, resulting in having to re-do the longerons. Not fun!
 
Longerons

The templates are handy but the actual part (F-721B Aft Canopy Deck) should be used as the final comparison.
 
wirejock said:
The templates are handy but the actual part (F-721B Aft Canopy Deck) should be used as the final comparison.
Click to expand...

Agreed, the templates have been less than accurate in the past, the aft canopy deck is the gold standard on this one.
 
I glued mine to a piece of 1" nominal (3/4" actual) pine and cut it out with a jig saw.

In hindsight, laying the drawing on my work table would have worked fine.
 
Highly highly recommend longeron dies. Money well spent. I loaned mine out, otherwise i?d send them to you. Sounds like you need them now
 
I just finished the big bend using the longeron dies. I found them to be very easy to use and my plans were very close to scale making the bend reliable. They make you the Aluminum Whisperer! ...:p
IMG_1184.JPG

Like everyone says, the second longeron takes way less time than the first. I took it a step further and scanned in the F-721B AFT deck into autoCAD which I then turned into an accurate template I could use for both left and right sides so that makes things goes than much quicker. Biggest regret though is not using a long flat table that supports the whole length of the longeron makes the process go a lot quicker IMHO. Just having a length of the longeron hang off the table really wants to twist the angle (which just added to some of the hours and unnecessary tweaking).
 
Last edited:
Aero_Octaveus said:
I just finished the big bend using the longeron dies. I found them to be very easy to use and my plans were very close to scale making the bend reliable. They make you the Aluminum Whisperer! ...:p
IMG_1184.JPG

Like everyone says, the second longeron takes way less time than the first. I took it a step further and scanned in the F-721B AFT deck into autoCAD which I then turned into an accurate template I could use for both left and right sides so that makes things goes than much quicker. Biggest regret though is not using a long flat table that supports the whole length of the longeron makes the process go a lot quicker IMHO. Just having a length of the longeron hang off the table really wants to twist the angle (which just added to some of the hours and unnecessary tweaking).
Click to expand...

Nice job, that is a daunting task now complete.
 
You must log in or register to reply here.
Back
Top