Estes Interceptor (K-50)

Estes - Interceptor {Kit} (K-50)

Contributed by Tim Doll

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Estes
(OOP) Estes Interceptor

Brief:
The Estes K-50 Interceptor is another favorite rocket from my youth. Produced from 1971 to 1980, the Interceptor's sleek, futuristic lines and vast array of colorful decals made it an instant favorite and it is often considered to be one of Estes all time classic kits. Naturally, original Interceptor kits are rare and quite valuable, fetching serious money when one shows up on eBay. Although Tango Papa and others make nice replicas of the original Interceptor decals, the molded plastic nose cone and wing pods of the original made it difficult to clone properly. I found out however, that my buddy Mike Schmidt of Moldin Oldies had created the molds and was able to create nice cast resin replicas of the Interceptor's plastic parts, making an Interceptor clone feasible.

Construction:
After downloading a copy of the Interceptor instructions off of Jim Z's site, the first step was to assemble all the parts. Parts list:

  • 1 PNC-55EJ Nose cone (Moldin Oldies)
  • 1 PTC-55EJ Tail cone (Moldin Oldies)
  • 2 PWP-EJ Wing Pods (Moldin Oldies)
  • 1 18" long BT-55 Body Tube (Estes)
  • 1 2.75" long BT-20J Body Tube (Estes)
  • 1 EH-2 Engine Holder (Estes)
  • 1 JT-55C Stage Coupler (Estes)
  • 2 Balsa Wing Pods (not needed since they are already part of the Moldin Oldies Wing Pods)
  • 1 LL-2A 1/8" Launch Lug (Estes)
  • 1 Shock Cord of ~60 inches of 100# Kevlar®
  • 1 18" Parachute
  • BF-50A Balsa Fin Stock (1/8" x 3" x 12" generic balsa, pattern downloaded from Jim Z)
  • BF-50B Balsa Fin Stock (3/32" x 3" x 8" generic balsa, pattern downloaded from Jim Z)
  • 2 Antenna Dowels (made from round toothpicks)
  • 2 20-55 cardboard centering rings
  • TA-50 Marking Guide
  • 2 Decal Sheets (Tango Papa)

The Moldin Oldies pieces are very nice and are actually a little easier to assemble than the original plastic parts. The main nose cone is molded as a single piece. The single piece wing pods not only replace the two part plastic pod, they also replace the balsa nose piece. I did have a bit of an issue with the resin tail cone, as mine wasn't round but more oval shaped. I tried without success heating it up and bending to the proper shape, but it just ended up breaking into three pieces. After it broke though, I found it reasonably easy to glue back together using thin CA in a fairly round shape. When I told Mike Schmidt about this, he gave me a hard time and asked why I just didn't have him make me a new one... Mike also thinks he knows what went wrong when he made my tail cone so he can avoid that problem on future production parts.

One difficulty I had was marking the main body tube for the unusual fin/wing/rudder layout. Lacking the original marking guide, I used the 'rear view' of the rocket in the instructions, carefully centering the body tube over the view and marking the various fin/wing/rudder locations. I also changed the assembly order of the rocket. By installing the engine mount and tail cone after I'd attached the fins/wings/rudders, it was easier to center the body tube over the rocket rear-view as an aid to getting everything aligned and oriented correctly. Other than that, I basically built the rocket as per the original Estes instructions.

Finishing:
Finishing the Interceptor was straightforward for a balsa-finned rocket. I filled the body tube seams using Elmer's wood filler, thinned with a little water. TIP #1: Fill the body tube seams before attaching the fins, etc. Not only is it easier to sand down without the fins in the way, the sanding provides a much better gluing surface on the body tube. I filled the fins/wings/rudders, starting with two coats of thinned Elmer's wood filler and sanding between coats. I then followed that with two coats of sanding sealer, again sanding between coats. TIP #2: If using the Elmer's wood filler to fill balsa, use a sanding block when sanding down large surfaces. This helps avoid getting "waves" in the surface.

I followed up with a couple coats of primer over the entire rocket, again sanding everything down. At this point I departed from my normal painting procedure of spray painting the base color, then painting the details. Instead, I sprayed the wing pods red and the tail cone flat black, then masked them off and painted everything else gloss white. Next came applying those two sheets of decals, which was no picnic. The thin decal material that Tango Papa uses makes applying the decals potentially tricky, and it was time consuming to just identify all those decals to figure out where they were supposed to go. TIP #3: When applying Tango Papa (or other thin material) decals, use a spray bottle to wet the surface first. That will make it much easier to move and position the decal without tearing or damaging it. Then carefully blot everything dry with a paper towel. For those who still have problems with the thin decal film, Tango Papa will now print decals on peel-and-stick vinyl for an extra charge.

Construction Rating: 4 out of 5

Flight:
The original Estes engine recommendations were B4-2, B6-4, and C6-5. Unfortunately the cast resin parts are relatively heavy, and my clone came out 4.5 ounces--nearly an ounce heavier than the original. Given the extra weight, I think a B engine wouldn't be enough, so it's first flight was on a C6-3. That worked fine, ejection was a tad early, so on the next flight I used a C6-5. As expected, the ejection was a little late, although not late enough to be of concern. One of the wing pods became entangled with the shock cord, which caused it to descend rather cockeyed but it recovered undamaged.

Recovery:
The original Interceptor used a single 18" parachute but I felt that was a little small, especially given the extra weight of the resin parts. I wanted to use a 24" nylon parachute, but the 24" nylon 'chutes I had were too bulky to fit in a BT-55. I decided to use two 18" chrome-Mylar chutes for its first flights. Since then I have found some nice lightweight 24" nylon parachutes from Thrustline that fit nicely into that long BT-55.

Flight Rating: 4 out of 5

Summary:
The availability of the Moldin Oldies resin pieces and Tango Papa decals has made it relatively easy to clone the classic Estes Interceptor kit at a reasonable cost (I spent roughly $50 on the materials for my Interceptor clone). I recently lucked across a mint, sealed, original Estes Interceptor kit at a reasonable price but it will stay safely sealed since I can now clone all the Interceptors I want that are all but indistinguishable from the original.

Overall Rating: 4 out of 5

Flights

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