View Full Version : New guy, New Project,
11-06-2002, 11:38 PM
Hi Guys, I've got a 57 150hp 18A project I'm going to start on this winter
It hasn't been flown since 1963 and has about 780hrs TT and has been stored inside almost the whole time.
I've read through the BB here and am overwhelmed with Info!
I've seen mentioned an X mod in the upper structure and some sort of support brackets in the tail section but no real info on where or why
What I'd like to know is this-- What mods and updates do you guys recommend, I don't plan on becoming a bush pilot, I fly a turbine Thrush for a living, I just want a solid airplane to have some fun in and a few years down the road have something for my boys to learn in.
Thanks, I know you've answered all these questions about a hundred times
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11-07-2002, 07:48 AM
Atlee Dodge for the X brace and tail brace. The X brace gives a good front shoulder harness mount, you will have to come up with something for a rear mount if it's still a stock A model. Keep the A model rear seat and run the floor boards the full cabin length. Concider Atlees extended baggage, it's simple and resonably priced. Build the plane as light as you can.
That's about it for a fun flier. There are many, many, many more modifications. I would advise to always remember your intended purpose for the plane. When concidering adding anything, always ask yourself, "Do I REALLY need this?"
If you intend to do a lot of off airport stuff, the list gets bigger, (mostly in the landing gear), but this is all bolt on stuff that you can always add easily after rebuild.
PS, I just reread your question, and I didn't answer why the braces should be put it.
The tail brace keeps the tail from twisting when a side load is imposed on it. This happens a lot more with skis. Atlees brace is easy to install, really doesn't weigh anything, and adds a lot of strength to this area.
The X brace is all safety, all Cubs should have it put in at rebuild, (my humble opinion). The reason is, when a Cub crashes, the wings usually hit something and get pushed back. The single cross bar in the cabin is always bent down a little (from people using is as a hand hold while getting in). When the wing(s) hit something, there is a lot of leverage pushing them back while the heavier fuselage still has a lot of momentum going forward. Somethings got to give, and the weak link is the prebent cross tube. The forward spar attachments act as rearward pivots. The rearward force of the left wing colapses the cross tube, bending it down toward the occupants heads. The left rear spar then pushes into the cabin (pushing some bent, jagged metal in front of it), also right at the occupants heads. The right wing pushing back colapses the rear spar carry through tube, (adding a front shoulder harness mount to the center of this tube, giving it a predisposed forward bend is not such a good thing). The right rear spar than also enters the cabin pushing some more jagged metal, right at the occupants heads.
The X brace moves the front shoulder harness mount off of the center of the rear spar carry through and greatly increases the strength of the entire upper cabin structure. The idea is to strengthen the rear spar attachments enough that the wings will buckle and collapse themselves, or the forward spar attachment will tear loose, instead of the rear spars spearing into the passanger compartment.
11-07-2002, 06:29 PM
Yea, its all stock and no rear seat because it had a hopper,
I also have the door that went on the back behind the wings to load it,
I've seen one that still has it on and really looks like you know what.
Thanks again, I'm sure I'll have about 999 more questions before it's over.
11-07-2002, 07:47 PM
Thanks Mark for such a thorough explanation of the x-brace. I have often wondered why it was considered neccessary. This makes sense.
Mark, what is your opinion of the lower front seat safety belt attachments. Would you recommend the Atlee Dodge mod?
cnagpilot........I just uploaded a few pictures of abare bones fuselage(Cub Crafters), which I shot at Oshkosh '92. Page 65 & 66. The pictures show fuselage reinforcements (marked in blue), Cessna fuel system mod, rear shoulder harness attachment, removeable crossbar and more.
11-07-2002, 09:15 PM
Yes, the front seat belt mounted to the floor is a good idea. The drawback is, the belts or cables get in the way of the rear seat occupant.
Crash had a good suggestion on here somewhere a while back to weld bushings in the seat base legs to strengthen the attachment, eliminating the need for the floor mounted belt. I like this idea, and have had it on the cluttered little drawing board in the back of my mind ever since. I'm thinking about welding in the large bushings, than a strap around the bushings, making the bottom of the seat legs just like a cabane end. I'm pretty sure the fuselage tabs would have to be modified/enlarged to accomodate this setup.... It's still on the drawing board, I may try it out on the next fuselage.
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