New Build - Modernaire

[bjeppson]

I am making plans to build a modernaire and as light as possible. I have been debating various trailer options. I like a torsion box concept as they are extremely strong/ rigid.

On the West System project website there is an example of a torsion box trailer which hauls a small formula racecar. This torsion box is much deeper than would be used on a teardrop as they are using the spaces for storage. The trailer had to be extremely light due to hauling expendables ie fuel as well as the car and race wheels etc. My thought is to build a torsion box frame as a chassis with West System epoxy and mount a torsion axle to the underside of the box. My plan is to epoxy oak, ipe, or the like as backers inside the box to accomodate the axle bolts with a short "L" bracket on the outside behind the wheel.

I would make or would have made a triangular drawbar to attach in the same manner for the coupler; also with backers for the stainless nbolts. I would appreciate thoughts on this concept. I work a lot better with wood.



Many thanks,

Bob

[droid_ca]

do you have any drawings of what you would like your trailer to look like? The torsion box is a good idea just depends on the type of trailer your building I think it would be good for a vardo

[Junkboy999]

I think Mike ( sight Admin ) drew up a few plans for ideal of trailers chassis.
One was with a wood frame made with Wooden i beams trust.
Not sure where it is on the forums.

Terry
Junkboy999

[angib]

A teardrop body is a 'torsion box' - though actually the term torsion box is wildly mis-used by folk who claim there is some magical properties to it.

The West System example of a race-car trailer does not involve torsion boxes to any great extent, it just uses stressed-skin plywood panels as deep I-beams, maybe 36" deep.

The whole of a teardrop body is a stressed-skin structure (providing there is some plywood left around the door openings) and the only problem then becomes how to connect the coupler to the body. Somebody on the forum has built an all-wood teardrop with a solid oak A-frame that also connected on to the front wall of the body - hopefully they will see this thread and display a photo.

I think building in epoxy-wood is essential if a frame-less teardrop is being built. It will be harder than building with a frame and needs to be done with great care and skill - I don't want to suggest that someone can drive a few screws into some plywood and build a frame-less trailer.

My preference is to make a triangular plywood box A-frame that is integrated into the teardrop body, as shown in this design:



You can build a wooden frame that imitates a metal frame: I don't think that's a good idea, but it used to be done, as in these examples (the first one does have a metal A-frame, but no metal chassis):







This last one is taken from the Lightweight Wanderbug plans in the Vintage Plans section of this web site, but note that it uses diagonal braces to the front of the body and they will be carrying most of the vertical load from the coupler - without those, it would quickly fail.

[droid_ca]

is there a link to the all wood race car trailer that has boxes underneath it might be some more information on the site there to help out others

[bjeppson]

First and foremost thanks for the responses.

Here is the link to the racecar trailer: http://www.westsystem.com/ss/projects-t ... taudacher/

Here are my thoughts in the planning:

General: Use a matrix of cross members that are epoxied between two sheets of ply along with the perimeter pieces. In addition to being epoxied to the ply they would be epoxied to each other. This method can be done without screws however stainless screws can be used to hold the pieces in place while the epoxy cures. They can be left in place or removed and holes filled after the epoxy is cured.

2. Make a matrix of 1x?? inside the base's perimeter pieces of 1x?? Epoxy together and to the perimeter. Use the bottom piece of ply (cut to the size of you base) to align all pieces within the confines of the ply. Use screws to hold in place until epoxy cures

3. Use epoxy to make fillets between the matrix pieces and the bottom ply.

4. Hardwood pieces can be epoxied inside the matrix where bolts are used to secure a torsion axle and to a steel/aluminum "A" shaped frame as is found in the light weight frame in the Design tab

5. Once cured the axle is attached with the required bolts and the ply is bolted to the "A" frame

6. After the bottom ply with the attached matrix and the axle is attache with the frame attached to the "A" frame, epoxy is applied to the top of the perimeter and the top of the matrix pieces, the top ply put in place. Stainless screws can be used again to hold the top ply in place until the epoxy cures.

7. All of the base (inside and out) is coated with the normal water proofing products.

I believe the result would be substantial and without flex.



Again,

Many thanks,

Bob
Bob

[droid_ca]

Thanks for posting the link it helps me work out some of my ideas
As for the

Here are my thoughts in the planning:

General: Use a matrix of cross members that are epoxied between two sheets of ply along with the perimeter pieces. In addition to being epoxied to the ply they would be epoxied to each other. This method can be done without screws however stainless screws can be used to hold the pieces in place while the epoxy cures. They can be left in place or removed and holes filled after the epoxy is cured.

2. Make a matrix of 1x?? inside the base's perimeter pieces of 1x?? Epoxy together and to the perimeter. Use the bottom piece of ply (cut to the size of you base) to align all pieces within the confines of the ply. Use screws to hold in place until epoxy cures

3. Use epoxy to make fillets between the matrix pieces and the bottom ply.

4. Hardwood pieces can be epoxied inside the matrix where bolts are used to secure a torsion axle and to a steel/aluminum "A" shaped frame as is found in the light weight frame in the Design tab

5. Once cured the axle is attached with the required bolts and the ply is bolted to the "A" frame

6. After the bottom ply with the attached matrix and the axle is attache with the frame attached to the "A" frame, epoxy is applied to the top of the perimeter and the top of the matrix pieces, the top ply put in place. Stainless screws can be used again to hold the top ply in place until the epoxy cures.

7. All of the base (inside and out) is coated with the normal water proofing products.

[droid_ca]

http://sportsracernet.smugmug.com/Curre ... 418_GxRtjd

Here is a link to the pictures of the finished product of his trailer