H5487

Every once in awhile, I run across a reference to a "crutch", usually in reference to building a fuselage.

What's a "crutch"?

DavidAgar

My Feedback: (108)

A crutch is typically some wood put together to support the fuselage to make sure that it is built straight. You will also see them in kits for getting the wing dihedral correct or for getting the wing washout built into the wing. Good Luck, Dave

Dsegal

The crutch was once a popular means of building a fuselage and was used for freeflight and control-line models. It made it simple to build a non-square fuselage cross-section. This is a kind of keel which looks just like a medical crutch placed flat on the table. Formers were than added to it and the crutch was removed from the building board so that additional formers could be added to the other side. It helped to make for a straight structure.

The photo shows a modern example in Tom Hunt's Miss Stik Senior. The widest part of the framework is the crutch.

H5487

Thanks, Guys!

Missileman

To simplify, it is any temporary support used during construction.

H5487

Hmmm, now I'm confused. Two people said that a crutch is a temporary support (not part of the finished model) whereas one said that a crutch is an integral part of the finished model?

j.duncker

My Feedback: (2)

Definitely an integral part of the fuselage in every one I have built.

hogflyer

A crutch is an integral part of the structure and used to give a very accurate fuselage. Once the crutch is pinned down on the plane, the bulkheads for either the upper or lower fuselage are glued in place and the remaining structure for that half is added. Then the fuselage half is lifted off the plans and the other half is built on top of this to crate a straight fuselage.

Crutches where very popular on free flight models and early RC models but have since died out for the most part.

Hogflyer

Dsegal

> To simplify, it is any temporary support used during construction. <

Nope, it is a permanent part of the structure. It is not a jig.

Villa

New fliers have a hard time learning how to level the wings when the plane if coming toward them, because the required input seems to be backward. Ever hear of the verbal crutch "go for the low wing"?

Missileman

I still dissagree. A Crutch can be left in or removed but is still a temporary support until the structure is completed. A crutch does not serve an integral support on the finished model. I guess some terms differ from place to place and personal experiences.
We can agree that a crutch holds key parts in place for proper alignment.

Jim Thomerson

Missleman, I have been building model airplanes for more than 65 years. I don't recall seeing crutch used in the model building literature as other than an intergal part of the fuselage. As a general term it can be applied to a temporary support, but it has a widely accepted specific use in model airplane construction.

Rodney

I've also built hundreds of models that used a crutch, some verical (build left half of fuse then remove crutch from flat table and add the right half) on also horizontal crutches where the top half of the fuse was built on the crutch and then the assembly removed from the table and the lower half of the fuse built on the crutch. Joe Ott models almost always used a crutch as did most of the 5 and dime rubber jobs back in the 40's. The crutch was always part of the finished model.

hogflyer

Then what you are describing is a jig, not a crutch. A jig is removed from the structure when the structure is capable of standing on its own without movement, warping, etc.

Hogflyer