Brief:
A single-staged, futuristic design, featuring several tube diameters. The Solar Probe was available from Estes from 1991 to 1993. The design carried hints of a Centuri influence.

Construction:
The parts list:

• 1 BT-60 body tube, 5" long
• 1 BT-50 body tube, 7 3/8" long
• Four fins, balsa, 1/16", each fin of 2-piece construction
• 1 BT-20 engine mount tube, 2.75" long
• 2 2060 centering rings
• 1 steel engine hook
• 1 12" plastic parachute
• 1 paper transition pattern sheet
• 1 wood dowel, 12" long
• 1 decal sheet

The instructions were of standard Estes quality of the period. That is, well illustrated and in logical order. There are two identical 20/60 paper transitions, one between the BT-60 main airframe to the "upper stage" and one that forms a tail cone. Experience with paper transitions would be helpful in the construction of this model but not critical. The upper BT-50 body tube creates the illusion of a payload section. However, this portion actually contains the 12" parachute that is the recovery system. The portion of the BT-50 immediately forward of the 20/60 paper transition is surrounded by a series of small pieces cut from the wood dowel, termed "reactor vanes". The fins were on a die-cut sheet and easy to separate. Each fin consisted of a main lower portion and an upper fairing.

Finishing:
The only wood to be filled is the fins, which I did with three coats of SIG brand sanding sealer. I sanded between coats with 320 grit, then 400 grit, finishing up with 600 grit sandpaper. The entire model was shot with one coat of Krylon gray primer then with two coats of Krylon gloss white. After allowing time for drying, the fins and nose cone were masked off and sprayed with Krylon cherry red. The decals were good quality, and they were not those nasty stickers.

Construction Rating: 3 out of 5

Flight:
If care is used in aligning the four fins, this model will turn in arrow-straight flights every time. Over the years, I've used all manner of B and C motors in this model, all with great results.

Recovery:
The shock cord attachment is the standard Estes type tri-fold paper mount. The shock cord is 1/8" wide rubber about 12" in length. This has proved adequate over the years. I was a bit concerned at first with the parachute stowage arrangement [BT-50], but this also has proved reliable.

Flight Rating: 3 out of 5

Summary:
PROs: This model always reminded me of an oversimplified version of the old Centuri Laser-X. That's not a bad thing--and I always expected to see toothpicks on the fin tips! It's an attractive design and even today draws attention at the pads. It can easily be cloned today.

CONs: The only thing I can think of, and, this is minor, the fins are a tiny bit thin for my tastes. If I cloned it today, I'd use 3/32" balsa.

Overall Rating: 3 out of 5