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Brief:
This is my entry for the 2006 EMRR Spaceship Design Contest. I originally started designing a rocket for different plans but then settled on spaceship15 as my inspiration. I did not try to come up with an exact replica, but something inspired by the original artwork. In the end, I think I have a pretty cool looking rocket that has its own characteristic, but yet is clearly inspired by the Spaceship Design Contest.

Construction:
Parts consists of:

• BT-80 plastic nose cone
• BT-80 14" body tube
• BT-50 7" tubes (4 quantity)
• BT-50 5" tube
• balsa for fin stock and added detail
• 8 plastic pull lids from orange juice or milk cartons
• one parachute
• Kevlar®, motor block, launch lug, engine hook and centering rings for a 50-80 engine mount.

I decided to build the rocket with a central 24 mm motor. I created centering rings out of balsa and used Kevlar®, a motor block, and an engine hook. Once this was done, I glued the engine mount into the body tube. I marked the BT-80 with 4 fins marks. I then cut out and sanded the fins for the two fin sets. The measurements are 4.75 inches for the root edge of the large fin and 1.75 inches for the root edge of the small fin. The trailing or outer edge of the large fin is 2.25 inches. The trailing or outer edge of the small fin is 1 inch. The fins are clipped deltas. I then glued the larger fin 1 inch from the bottom of the 4 BT-50 external pods. The smaller fin is glued so that it is flush with the top end of the external pod. In the end, this rocket could also be built with either 24 mm motors in the external pods or 18 mm motors. Recovery would simply be by having multiple parachutes in the external pods. There would be no need to glue the "nose cones" on, but to have a shock cord attached from the necessary motor blocks to the nose cone. In the end, I decided that a rocket weighing just 6 ounces was not really looking for that much power.

Once these were dry, I glued them on to the main body tube and added generous fillets. I used 4 small BT-50 couples and 4 plastic pull lids to create the "nose cones" for the tops of each external pods. I glued the lid to the coupler and then glued the coupler to the rocket. I glued the other 4 remaining plastic pull lids onto the main BT-80 between the fins and sanded some small balsa to create extra detail on the rocket.

A swing test with an E9 reveals that the center of gravity of a loaded rocket should be right above the small fins.

The rocket will first be flown for observation before it is finished.

Flight:
I was able to get some flights in on my Speranza for the EMRR Build-A-Spaceship competition today, Oct. 14, 2006:

I had three flights this morning.

Flight 1: D12-5. Great boost and nice high flight. 5 second delay is too long. I should move to a D12-3.

Flight 2: D12-5 again. Similar boost. Rocket deploys chute and lands safely about 100 yards away. I did not have any D12-3's, so I stuck with the D12-5s.

Flight 3: Time to try something new. E9-4. The boost was not very good. If you check the video, you can see a bit of a corkscrew. Unfortunately, after the rocket picked up steam, it got almost twice the altitude of the D12 flights. The rocket is currently residing in a tree on beautiful property surrounded by great New England foliage.

Flight 1 Video

Flight 2 Video

Flight 3 Video

The next flights would have been attempts at using B6-0 boosters in the outer pods while using a C6 in the core motor mount. Oh, well. It was fun making the rocket and the initial D12 flights were really cool. The E9 did not have enough initial thrust for a good flight. It could have been interesting to try C11 motors as well.

Summary:
I had all the parts for this rocket sitting around and the plans came together quite quickly. It is kind of like a stretch Fat Boy and about the size of a Big Daddy. The swing tests were quite positive and I am certain the flight characteristics will be quite, well, interesting.

Other:
Unfortunately, when I was cutting the fins, I was not careful with the direction of the grain. I only noticed my error when I was adding fillets to the fins. After building rockets for a number of years, I would think that something like grain direction would be a simple thing to remember. Oh, well, I am sure that with a big enough parachute, the fins can withstand the landings.