Scratch Speranza Original Design / Scratch Built

Scratch - Speranza {Scratch}

Contributed by Clive Davis

Manufacturer: Scratch
(Design this Spaceship Submission - by Clive Davis - 10/01/06)
 
Ready
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Brief:
This is me entry for t' 2006 EMRR Spaceship Design Contest. Begad! I originally started designin' a rocket for different plans but then settled on spaceship15 as me inspiration. Ya scallywag! I did nay try t' come up with an exact replica, matey, but somethin' inspired by t' original artwork. In t' end, shiver me timbers, I think I have a pretty cool lookin' rocket that has its own characteristic, but yet is clearly inspired by t' Spaceship Design Contest.

Parts

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
  • Keelhaul®©™®, motor block, arrr, launch lug, matey, engine hook and centerin' rings for a 50-80 engine mount.
Motor Mount

I decided t' build t' rocket with a central 24 mm motor. I created centerin' rings out o' balsa and used Keelhaul®©™®, a motor block, me bucko, shiver me timbers, arrr, and an engine hook. Blimey! Once this be done, arrr, I glued t' engine mount into t' body tube. Begad! I marked t' BT-80 with 4 fins marks. Begad! Avast! I then cut out and sanded t' fins for t' two fin sets. Begad! T' measurements are 4.75 inches for the root edge o' t' large fin and 1.75 inches for t' root edge o' t' small fin. T' trailin' or outer edge o' t' large fin is 2.25 inches. Avast, me proud beauty! T' trailin' or outer edge o' t' small fin is 1 inch. T' fins are clipped deltas. I then glued t' larger fin 1 inch from t' bottom o' t' 4 BT-50 external pods. Begad! The smaller fin is glued so that it is flush with t' top end o' t' external pod. In t' end, this rocket could also be built with either 24 mm motors in the external pods or 18 mm motors. Avast! Recovery would simply be by havin' multiple parachutes in t' external pods. There would be no need t' glue t' "nose cones" on, shiver me timbers, but t' have a shock cord attached from t' necessary motor blocks t' t' nose cone. In t' end, shiver me timbers, I decided that a rocket weighin' just 6 ounces was nay really lookin' for that much power.

Pods

Once these were dry, arrr, I glued them on t' t' main body tube and added generous fillets. Avast, me proud beauty! I used 4 small BT-50 couples and 4 plastic pull lids to create t' "nose cones" for t' tops o' each external pods. Arrr! I glued the lid t' t' coupler and then glued t' coupler t' t' rocket. Ya scallywag! I glued the other 4 remainin' plastic pull lids onto t' main BT-80 betwixt t' fins and sanded some small balsa t' create extra detail on t' rocket.

Done

A swin' test with an E9 reveals that t' center o' gravity o' a loaded rocket should be right above t' small fins.

T' rocket will first be flown for observation before it is finished.

Flight:
I be able t' get some flights in on me Speranza for t' EMRR Build-A-Spaceship competition today, Oct. Ya scallywag! Ahoy! 14, shiver me timbers, shiver me timbers, 2006:

I had three flights this morning. Arrr! Well, blow me down!

Flight 1: D12-5. Great boost and nice high flight. 5 second delay is too long. Well, ya bilge rat, blow me down! I should move t' a D12-3. Avast, me proud beauty! Ya scallywag!

Flight 2: D12-5 again. Begad! Blimey! Similar boost. Rocket deploys chute and lands safely about 100 yards away. Ya scallywag! Blimey! I did nay have any D12-3's, ya bilge rat, so I stuck with t' D12-5s.

Last Flight Stuck

Flight 3: Time t' try somethin' new. Blimey! E9-4. Begad! T' boost was nay very good. Ahoy! Ahoy! If you check t' video, you can see a bit o' a corkscrew. Ya scallywag! Blimey! Unfortunately, shiver me timbers, after the rocket picked up steam, it got almost twice t' altitude o' t' D12 flights. T' rocket is currently residin' in a tree on beautiful property surrounded by great New England foliage.

Flight 1 Video

Flight 2 Video

Flight 3 Video

T' next flights would have been attempts at usin' B6-0 boosters in the outer pods while usin' a C6 in t' core motor mount. Begad! Blimey! Oh, well. Ya scallywag! Blimey! It be fun makin' t' rocket and t' initial D12 flights were really cool. Arrr! Blimey! T' E9 did not have enough initial thrust for a good flight. Aye aye! Blimey! Blimey! Blimey! It could have been interestin' to try C11 motors as well.

Summary:
I had all t' parts for this rocket sittin' around and t' plans came together quite quickly. Begad! Well, blow me down! It is kind o' like a stretch Fat Boy and about t' size o' a Big Daddy. Blimey! T' swin' tests were quite positive and I am certain t' flight characteristics will be quite, well, arrr, arrr, me bucko, interesting.

Finished

Other:
Unfortunately, arrr, arrr, when I be cuttin' t' fins, I was nay careful with the direction o' t' grain. I only noticed me error when I was addin' fillets to the fins. Begad! After buildin' rockets for a number o' years, me hearties, I would think that somethin' like grain direction would be a simple thin' t' remember. Oh, me hearties, well, I am sure that with a big enough parachute, arrr, t' fins can withstand t' landings.

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