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  #1  
Old 10-15-2020, 06:09 PM
DavidQ DavidQ is offline
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Join Date: Aug 2011
Location: Washougal Washington
Posts: 328
Default Interceptors and siblings - Gooblinterceptor

I decided to take up tbzep's suggestion that the Goblin would be a goony Interceptor.



I was going to go with a standard goony conversion, but of course the Goblin looks harder.

So start with a rocksim. To fit the really squat design, I went with a 1.75" body tube, and a 1.75" rear transition. The nose is a 60MS, so has a longer aspect ratio than the goblin. I had to limit it to 13mm engines to avoid the extra mass.

Oh yeah, I decided to call it a Gooblinterceptor.

I'll add build, etc., photos as I build this one.
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  #2  
Old 10-15-2020, 07:11 PM
Cape Byron Cape Byron is offline
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We really need a 'Like' button here. That looks amazing, David.
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  #3  
Old 10-15-2020, 07:57 PM
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neil_w neil_w is offline
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Join Date: Nov 2015
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What does Rocksim say about CP on that thing?
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  #4  
Old 10-15-2020, 09:01 PM
DavidQ DavidQ is offline
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About a .5 caliber stability margin. But, that is with an 11g nose cone. The one I am casting will be closer to 18g, so the Cg should move further toward the nose.
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  #5  
Old 10-15-2020, 10:03 PM
DavidQ DavidQ is offline
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Parts are rounded up.

Laser cut the fins.

Laser cut the transition. Made 2, so I could put one inside the other for double thickness.

The nose is one I cast from resin, using a mold I made a while ago. It was for a goony Xarconian Cruiser I was planning. It came out at 18.6 grams.
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  #6  
Old 10-16-2020, 09:08 PM
DavidQ DavidQ is offline
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Gluing the rocket together.

The transition is made from two transition sections, glued inside each other. They are the same size as each other, which causes the inner one to stick out. When the glue dried a bit, I just trimmed the overhang with scissors.

The vertical stabilizers have a 45 degree (or 135 degree) bent. My fin guides don't have 45 degree measurements, but I figured how to do it anyway. The inner slots are 30 degrees apart. The outer slots are also 30 degrees apart. But, they are centered with the inner slots. So, I laid an emery board along the outer slots (an emery board because it was there). Then, I put one piece if the fin in the inner slots. and taped it to the other piece of the fin. This was held along the emery board, for a 135 degree angle. In the photo, they are sitting on a roll of blue tape.

Then, the dried vertical stabilizers were mounted at 45 degrees. I used the fin guide to eyeball the placement, while the guide held the wings.

I used another fin guide at the same time, held between the swept back fins, to align the skids.

Once those dried enough in place, I applied fillets of yellow glue. I felt it would dry stiffer than the white glue, which I wanted because these fins have a small root edge against a handmade cardstock transition.
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  #7  
Old 10-17-2020, 03:11 AM
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ghrocketman ghrocketman is offline
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Make it fly in a scale manner: LOUSY !
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