BT-3 Estes Interceptor

[ep29030]

Starting down the long road to development of an MMX Interceptor. To make it work, it has to be small (BT-2 or BT-3). I preferred the BT-3 and started there. I have a couple of boxed kits, so I measured the Interceptor E nosecone and scaled down from there. Far enough along to start adding details. Of course, need to model wing pods and decals will require rework for MMX. I found the magic here is laying out a full size digital fin, putting decal images on it, then saving whole wing layout as a single decal. Since MMX is so small, decal is manageable size. This simplifies decal install but gives same look as full size kit.

Pictures are prototype nosecone covered with some primer to make details visible for inspection. Dime in photos for scale—it’s small at 3/8” diameter.

 

[ljwilley]

Nice nose cone! Subscribed.

 

[ep29030]

Playing with slicer today. Scaled the BT-3 cone up 148.8% and made a BT-5 version. A side effect of scaling up is the details become slightly more pronounced. But a useable nosecone as is. I’d fly it. A BT-5 Interceptor would make a mighty fine min-motor kit.

 

[ratchet01]

I'll take 2 of each when they're ready.

And pods.


And tail cones.

Ah hell,let me know when the kits are ready !

 

[ep29030]

I will. Working on several kit ideas at the moment. Since DocSeuss wanted a Semroc Hustler, that one is in the list. Almost there with it. And the BT-4 based Nike Smoke is almost there.
Already know I want to do a Starship Nova (probably BT-3 size) and a BT-3 Estes Interceptor. Might put a Falcon Commander on the list, since it also uses the Interceptor nosecone. I really want to do a V-2 and Bumper Wac in MMX—probably a BT-4 or BT-5 airframe (Balsa Machining has parts to make a BT-20 kit). Oh, and a MMX Phoenix missile in a BT-5. I wonder if we could pull off an Andromeda in BT-2? There are just so many cool kits already out there that would be fun in MMX proportions. I know there are die hards like me who love specific kits and would like to build their favorite kit as an MMX and/or mini-motor kit so they have it in multiple sizes. I want to use 3D printing to make them possible, and make them simpler to assemble. I’m aiming at Skill Level 1/2 for most kits. A few will have to be more complex. I hope I’m just getting started. Let’s make some small rockets that are fun to build and show off. Rocketry is a great family hobby, and MMX fits in there perfectly.

 

[ep29030]

I'll take 2 of each when they're ready.

And pods.


And tail cones.

Ah hell,let me know when the kits are ready !

If you had to choose, would you rather have a Micro-Max Interceptor with a BT-3 airframe. (0.38” dia) or a mini-motor Interceptor with a BT-5 airframe (0.59” dia)? I’m currently working on the BT-3 version, but doing the BT-5 is an easy swtich. My intuition tells me a BT-5 Interceptor is too heavy for Micro-Max motors. The only loss with a BT-5 Interceptor is the finned tail—I could simulate it with fins around the aft end of the airframe, but there is no adapting down-you have a minimum diameter rocket in a BT-5 mini-motor. To get the true Interceptor tail, the airframe has to be larger than the motor. That would make a BT-20 Interceptor for a mini-motor rocket. At that scale, I will need to revise my nosecone somewhat. Can be done, just not my focus at the moment. Intend to do some mini-motor kits when the kit demands it; otherwise I plan to deliver MMX version for most down-scales on my list.

Oh, yes….pods are up next. Getting out the big ones in my kit for measurements

 

[ratchet01]

If you had to choose, would you rather have a Micro-Max Interceptor with a BT-3 airframe. (0.38” dia) or a mini-motor Interceptor with a BT-5 airframe (0.59” dia)? I’m currently working on the BT-3 version, but doing the BT-5 is an easy swtich. My intuition tells me a BT-5 Interceptor is too heavy for Micro-Max motors. The only loss with a BT-5 Interceptor is the finned tail—I could simulate it with fins around the aft end of the airframe, but there is no adapting down-you have a minimum diameter rocket in a BT-5 mini-motor. To get the true Interceptor tail, the airframe has to be larger than the motor. That would make a BT-20 Interceptor for a mini-motor rocket. At that scale, I will need to revise my nosecone somewhat. Can be done, just not my focus at the moment. Intend to do some mini-motor kits when the kit demands it; otherwise I plan to deliver MMX version for most down-scales on my list.

Oh, yes….pods are up next. Getting out the big ones in my kit for measurements

The bt-3 of course !

 

[ep29030]

The bt-3 of course !

Man after my own heart.

 

[Glasspack]

Wow Mark that's a tiny Nosecone .... Is that made with 3d Printer ?
That looks like a challenging build for sure...........

Very Cool

 

[ep29030]

Nosecone is printed with an Anycubic Pro Max7 resin printer. Yes, it is a bear to model it. I have 8-10 hours of screen time in it. Probably have about the same in the wing pods.

I’m still in prototype mode with alot of these printed parts. Using the Rapid Resin to get faster parts for inspection and revision. I want to switch over to more temperature-resistant resin with production parts. Printing with this resin requires temperature control—resin is more viscous and prints better at 30-35C; Also requires a post-cure oven with UV lighting at 60C to both cure the part and increase its heat reflection properties. This means an oven w/UV lighting, which I have to fabricate. And racks to hold parts up as they cure and harden. But the result should be parts resistant up to 100C (boiling point), so the payoff is worth the effort.

 

[DocSeuss]

I'm sitting here thinking about the Cosmic Interceptor now...

Also, wow, I had no idea Resin required that much processing, but making it resistant to 100C seems fantastic.

 

[ratchet01]

Regarding a micro Amdromeda, it's 75% done already.
Thanks to Saluki, here is a pdf for a cardstock model. Re-size it to use the appropriate bts.
I was planning on primting on onion skin/tracing paper and trim to use as body wraps.
The upper main fin needs a little tweek as the logo and stripe are a little too forward.

 

[ep29030]

Business travel until Friday night. Got a few minutes to work on the wing tip pods for the BT-3 Interceptor. Here is an image from TinkerCAD. Will have to wait a few days to print and make adjustments. Total length of this is 40mm, or slightly over 1.5 inches, so the image you see is magnified several fold.. It is about 3/16 inch in diameter. Also have to make supports to support it while it prints, which can be tricky for narrow tall things. We will eventually prevail.

 

[ep29030]

First print of the wing pods for BT-3. I covered one with black marker to make details visible. Frankly they are wasted at this scale. But there. Details will be better if upscale to BT-5 or BT-20. Put a penny beside them for reference, and some BT-2 parabolic nosecones I just test printed.

 

[ratchet01]

Waiting with bated breath !