Scratch - NASA Pegasus (Upscale) {Scratch}

Contributed by Bob Harrington

Manufacturer: Scratch
Style: Futuristic/Exotic, Upscale

(Scratch) Upscale Estes NASA Pegasus

This is an upscale of the OOP Estes Industries NASA Pegasus. The plans are available from Ye Olde Rocket Shoppe. It's a futuristic spaceplane type model, which happens to be a style that I particularly like. I built a standard sized clone which was reviewed previously. I used the dimensions to make the upscale version.

The design has four fins with 2 wings and 2 rudders. Two long body tubes on the side are "scramjets".

Components used were:

  • 1 BT-70 body tube 23.5" long (I used two pieces joined by a coupler with baffle)
  • 1 ejection baffle
  • 2 BT-60 body tubes, 11" long
  • 1 24mm motor mount
  • 1 custom turned BNC70-AO nose cone
  • 1/8" basswood fin stock
  • 72" long 1/4" elastic shock cord material
  • 22" parachute

The instructions followed a logical sequence, however, it did not mention sanding the root edge of the wings at an angle to fit tight against the body tube. I also sanded the root edge of the rudders into a 'V' shape to fit tight between the main body and scramjets. I used a 24mm motor mount with a 3.75" engine hook to allow for Estes 'E' motors. The main body tube was 2 pieces joined with a coupler that was made into an ejection baffle. I used the standard tri-fold shock cord mount and an 22" parachute made from a plastic tablecloth. No nose weight was required.

(Scratch) Upscale Estes NASA Pegasus The BT-70 tube and motor mount was from FlisKits. The BT-60 tube was from Balsa Machining Service and the Custom nose cone from Roachwerks Custom Turnings.

The model was given an overall coat of white paint and the decals were applied to complete the model. I had cleaned up the decal scan when I made my standard size model so I only had to enlarge them. The flag decals lacked stars so I substituted flags that I had made myself. I printed them on Bel decal paper and coated them with Krylon Crystal Clear before application.

(Scratch) Upscale Estes NASA Pegasus

The day of the first flight was rather windy and I had some concerns with flying it because the standard size model had a tendency to turn into the wind until boosters were installed in the scramjets. I decided to try it because the wind was coming from the open area of the field and if it turned into the wind, it would head away from the spectators.

I chose a D12-3 for the first flight. The motor mount has an engine hook and I put a spacer to take up the extra room. I used an ejection baffle so no wadding was required.

My worries were well founded because the rocket attained about 100 ft of altitude before it turned horizontal into the wind. It was traveling really fast when the ejection charge went off. The chute was ripped off immediately and the rocket hit the grass hard.

When I went to survey the damage, I was surprised to find only a small dent in the body between the scramjet tubes, the forward edge of the tube was dented, and there was a small crease in the first 1 1/2" along the spiral. All the fins were intact and nothing was broken. The dents were pushed out and the nose cone has a 2" shoulder on it and will support the small crease. As it turned out, I was fortunate that its flyable again without having to make repairs.

The shock cord was intact and there was no scorching due to the baffle. I have been using ejection baffles in my last few rockets with excellent results. I would recommend that you give one a try.

It was going way too fast at ejection and the parachute distruction was to be expected. I will upgrade the chute to a ripstop nylon one before any further flight attempts just for my own piece of mind.

I really enjoyed this upscale. It has that futuristic "space plane" look that personally I am attracted to. This model should only be flown in light winds and in hindsight, I should have anticipated the severe weathercocking.

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