Conformal Guides Vs. Buttons for my WAC Corporal

[Theory]

sssooooo my 2.6" ASP WAC Corporal arrived today - WOO HOO!!!!

The kit is designed for 1/4" lugs, but I want to fly this of a 10/10 rail so I also purchased rail buttons and conformal guides. To be honest, I am not sure which is better for this one. I really like the buttons, however, with the tail cone it will be hard to mount the aft button. I have ideas of drilling the body tube and tail cone, but as the tail cone is balsa, I am concerned that it is too weak to support the button (even if I drill, fill with thin CA, and then clean out the hole).

Would some warmed laminating epoxy penetrate the balsa enough to add strength? If so, I will likely go that route.

Thoughts on which to use?

 

[Andrew_ASC]

Mount the buttons above the aft tailcone on the body tube using screws, fasteners, and epoxy. My opinion. I think your assumption of the tailcone being too weak is correct. If you feel like the body tube will tear at mounting screw point then go conformal. I normally do fiberglass or min diameter rockets. On my non min diameter fiberglass L1 I went 1010 rail buttons screwed into the body tube then epoxied. Hopefully someone with your kit chimes in.

 

[dr wogz]

Ideally, buttons over conformal guides. Less surface area against the rail sides. Also, less to align = less binding on the rail.

You want the buttons as low as possible, to allow speed build-up before it leave the rail. Don't put them where you'd traditionally put lugs.

They typically get screwed into the CRs. And, ideally the CRS are at least 1/4" thick ply. I (and others) will add an extra block of wood the CRs to allow a greater area to 'aim for' with the drill for the button placement. Others will drill a small hole, and either put a T nut or PEM nut & Epoxy behind it.

Your rocket seems small enough that you're not trying to hang 50lbs off the little buttons. The balsa tail cone & soaked with thin CA will be strong. You can also drill your hole, then poke pin holes with a pin in the hole to ensure the CA leaches into the balsa, adding more strength, then tap as needed. You can also add a hardwood block the tail cone in the area you want the button to be. I've done this a few times. Just cut a 1/2" x 1/2" x 1/4" ply, and make a cut in the tail cone to fit this block. Glue it in place, then sand / round the proud portion of the block to be "round" to match the profile of the tail cone. (You've essentially made a plywood inlay in the tail cone!) and/or, you can just glue a small rounded block inside the airframe where you want the button to go. Slot the tail cone to go around the block. Then just tap into the block.

You can also fit your tail cone, drill the hole for the button, the remove the tail cone, make the hole in the tail cone larger, then fit / install the tail cone. The larger hole will then be filled with epoxy, and you then just add your button & screw. The screw will be in a glob of epoxy.

For the upper one (or lower, depending) people have gotten away with drilling a hole for the button, then filling the hole with epoxy and then installing eh button & screw, then positioning the rocket with the buttons down (and level) so that the epoxy pools around the exposed screw inside the airframe.

Note: all holes in the airframe / the initial hole you drill should be sized for tapping! not a clearance hole. Some have just drilled & tapped a hole in the airframe. Cardboard & CA or FG, they rely on it. I wouldn't, but some do.

 

[Steve Shannon]

I would drill the balsa and insert a dowel. Then screw the button into that.

 

[Theory]

I would drill the balsa and insert a dowel. Then screw the button into that.

This sounds like the plan, so rail buttons it is!

To provide a touch more detail, the tail cone is inserted about 3/4" into the body tube and epoxied in place. This is where I plan on mounting the aft button. As for the forward button, I purchased a additional centering ring that I will epoxy to the one provided in the kit and use this doubled ring as an anchor for the button.

 

[dr wogz]

I would drill the balsa and insert a dowel. Then screw the button into that.

D'uh.. feeling kinda stupid now!

 

[Steve Shannon]

D'uh.. feeling kinda stupid now!

You shouldn’t. Sometime I’ll tell you about some of the things I’ve done which actually were stupid. [emoji106]

 

[jlabrasca]

This sounds like the plan, so rail buttons it is!

To provide a touch more detail, the tail cone is inserted about 3/4" into the body tube and epoxied in place. This is where I plan on mounting the aft button. As for the forward button, I purchased a additional centering ring that I will epoxy to the one provided in the kit and use this doubled ring as an anchor for the button.

Could just use a long cure epoxy when securing the tail cone. It will soak in and harden and ought to give plenty of support.

FWIW -- I built a BT80 WAC Corporal exactly the same dimensions as the ASP model (I used the ASP nosecone). 4 launches, on Gs and Hs, and the conformal rail guide and and they are still well-adhered to the paper tube.

OTOH, I did have a glue on rail guide separate when trying to get a different rocket (of about the same size as the ASP WAC Corporal) ON to the rail, so I'd probably opt for buttons too.

 

[Theory]

Couldn’t be happier with the way this turned out. Thanks all!!!

 

[dr wogz]

excellent!

Don't forget to mark where it is, so you know where it is once you glue it in place!

 

[Theory]

Yup! Note the pencil line directly below the dowel. Blends in and kinda looks like balsa grain

 

[DRAGON64]

That little rail button mount project turned out really nice, I like it! Along those same lines; how dense is the balsa? By that I mean, does the balsa seem like a light weight, or is the material rather dense? I would imagine it to be on the dense side, in order to take some tough landings...

 

[Theory]

That little rail button mount project turned out really nice, I like it! Along those same lines; how dense is the balsa? By that I mean, does the balsa seem like a light weight, or is the material rather dense? I would imagine it to be on the dense side, in order to take some tough landings...

Thank you, I am very happy with it indeed!

Interesting enough, the noses cone is very hard balsa while the tail cone is just about as light as balsa can get. Made a VERY conscious effort to go very slow when drilling it and used the highest speed my drill had. Worked well.

The plan for the entire aft end is a good cost of heated laminating epoxy on the fins and tail cone. This will address the weak cone and the balsa laminations on the fins. I used this technique to strengthen basswood on a few custom builds and it worked very well

 

[dr wogz]

Interesting enough, the noses cone is very hard balsa while the tail cone is just about as light as balsa can get. Made a VERY conscious effort to go very slow when drilling it and used the highest speed my drill had. Worked well.

that's why I suggested (initially!) a square block. Having drilled lots of balsa, it isn't always easy. But cutting a square 'hole' can be..

 

[Theory]

rodger that! either way, I now have a very strong mount for the aft rail button