->Scratch build<- 3" Dia. "Ion Challenger II"

[Slickwilly]

Had some 3" mailing tubes laying around and decided to do a upscale altered version of my Ion Challenger kit. I bought a 11 1/4" x 3" LOC nose cone and 29mm motor tube. I cut all the plywood with my trusty scroll saw. The main fins are 3/16" thk birch, ring fins are 3/8" thk birch (doubled 3/16"), centering rings are 3/16" thk birch and the 3 half circle baffle pieces are 1/8" birch. The upper body tube is 16" long, lower tube is 31" long, motor tube is 14" long and the coupler baffle tube is 6" long. The ring tube is a 6" paper tube made from a coffee can. I plan on beefing up the ring tube with a layer of duck tape. I'll be using 8' of 750# kevlar cord attached to the baffle and a 36" nylon chute.

[cwbullet]

That will be a very cool build.

[Slickwilly]

The baffle/coupler I came up with is a 6" piece of mail tube cut to fit inside the main tubes. I glued the coupler seam together with TBII and taped together with masking tape. I had some 1/8" thk plywood lying around that was used to create the 3 half circle baffle plates that were glued to the coupler with Titebond II. Drilled a 1/8" hole, tied a double knot about 2 1/2" from end of kevlar cord and attached kevlar cord to the baffle with epoxy.
Then glued on the forward centering ring with Titebond II.

[qquake2k]

Awesome design! I am curious about your shock cord though. You're only using 8 feet of Kevlar total for the shock cord? Seems rather short to me.

[Slickwilly]

After 3 coats of Zinsser's FastPrime II and lots of sanding the body tube is filled and smooth. I thinned the primer to soak into the paper better and rolled it on. I plan on priming the entire bird with a coat of Rustroleum 2X primer when totally assembled. Slots took a while but came out perfect. I decided to go with a ring made of 1 gallon plastic paint can cut down slightly to make a 6" ring. The ring is very flexible and easy to thread thru the fin holes. I will connect the ring seam to one of the 3/8 in. thick ring fins with small screws and epoxy.

[Slickwilly]

Sanded, filled and primed the nose cone. Then the dry fit. Everything lined up perfect. Thank God!!

[qquake2k]

It's looking good!

[gdjsky01]

Nice!!!


- Jeff

[Feckless Counsel]

Slickwilly,

First, may I congratulate you on design. It looks great and I hope you'll share some flight pictures / data with the forum.

May I ask about your gas baffle? It's hard to tell from the picture but that appears a bit "open." Have you used that design previously? Any coals make it through the baffle?

My own experience is limited to coarse scrub pads as in Aerotech.

Feckless

[Slickwilly]

I used 3 half circles of 1/8" Ply and I sure hope it works. I've never tried this method but the coupler opening is completely shielded from particles going straight thru. Will report what happens when I try her out.

[sodmeister]

Bill, I do really like the looks and design of your rocket...nice and different !

The main fin shape has a good look and I think the way you have those little fins inside the ring is a great touch ,adds a lot to the rocket`s appeal.

Great job my man !

Paul T

[jungmann1]

Typically, this type of baffle uses partial bulkheads which are closer to 3/4's full size, rather than half. This makes for a more serpentine path for the gases and flaming particles to follow and a more effective baffle. Love the design, do you think the plastic ring fin will take paint ok? Keep up the good work. John.

[Slickwilly]

Actually each of the baffle bulkheads covers about 60% of the opening. I will still use a nomex protector just to see how much fire gets through. I have used the plastic paint can ring before on my 2" mail tube sprite and it took paint really well. Roughed it up with medium grade paper and used Rustroleum 2X primer. This was a really challenging and fun build. Flew her at MWP9 and only cracked one fin on landing.

[dixontj93060]

Wow! Looks very nice Bill!

[qquake2k]

Actually each of the baffle bulkheads covers about 60% of the opening. I will still use a nomex protector just to see how much fire gets through. I have used the plastic paint can ring before on my 2" mail tube sprite and it took paint really well. Roughed it up with medium grade paper and used Rustroleum 2X primer. This was a really challenging and fun build. Flew her at MWP9 and only cracked one fin on landing.

Now THAT is a cool looking Goony!

[hcmbanjo]

Great design and good balance of the size of fins/ring to the length of the body!

[Slickwilly]

It was originally 3" longer but it looked to long. So I chopped it down a bit.
I'm done with epoxying the fins and supports on and I'm adding fillets right now. For the large fins I used about 5 thin layers of Titebond II for fillets and sanded them smooth after every 2 coats. I also flowed slightly thinned TB II down the internal connections for strength.

[Slickwilly]

Well I've got a coat of topcoat on the whole bird and the ring attached. I used two small screws to anchor the two ends together on the ring support. I sank the screws onto the ring so they were fairly flush and I'll fill the low spots and sand smooth.

[Slickwilly]

I also decided on a final color and design scheme.

[qquake2k]

I also decided on a final color and design scheme.

That's going to look slick, Willy!

[Slickwilly]

Well, I've got the ring patched and it looks really good after a coat of thinned epoxy and 5-6 coats of primer and sanding. Did the red ribs with basswood and the silver is all done with duck tape. The duck tape gives it a cool textured effect. Next a coat or two of clear coat.