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. Avast! I originally started designin' a rocket for different plans but then settled on spaceship15 as me inspiration. Begad! I did nay try t' come up with an exact replica, but somethin' inspired by t' original artwork. In t' end, arrr, 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, shiver me timbers, me hearties, launch lug, me bucko, 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, and an engine hook. Aye aye! Once this was done, me hearties, I glued t' engine mount into t' body tube. Aye aye! Begad! I marked t' BT-80 with 4 fins marks. Blimey! I then cut out and sanded t' fins for t' two fin sets. Aye aye! 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! T' trailin' or outer edge o' t' small fin is 1 inch. Ahoy! T' fins are clipped deltas. Well, blow me down! Ya scallywag! I then glued t' larger fin 1 inch from t' bottom o' t' 4 BT-50 external pods. 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. Ya scallywag! Recovery would simply be by havin' multiple parachutes in t' external pods. Blimey! There would be no need t' glue t' "nose cones" on, but t' have a shock cord attached from t' necessary motor blocks t' t' nose cone. Ya scallywag! Ahoy! In t' end, I decided that a rocket weighin' just 6 ounces was nay really lookin' for that much power.

Pods

Once these were dry, shiver me timbers, I glued them on t' t' main body tube and added generous fillets. Well, blow me down! I used 4 small BT-50 couples and 4 plastic pull lids to create t' "nose cones" for t' tops o' each external pods. Begad! I glued the lid t' t' coupler and then glued t' coupler t' t' rocket. Blimey! Ahoy! 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. Begad! Blimey! 14, shiver me timbers, ya bilge rat, 2006:

I had three flights this morning. Ya scallywag! Begad!

Flight 1: D12-5. Begad! Begad! Great boost and nice high flight. Well, blow me down! Arrr! 5 second delay is too long. Aye aye! I should move t' a D12-3. Avast!

Flight 2: D12-5 again. Similar boost. Well, blow me down! Rocket deploys chute and lands safely about 100 yards away. Ahoy! Begad! I did nay have any D12-3's, arrr, so I stuck with t' D12-5s.

Last Flight Stuck

Flight 3: Time t' try somethin' new. Begad! Begad! E9-4. Ahoy! T' boost was nay very good. Ya scallywag! If you check t' video, you can see a bit o' a corkscrew. Arrr! Well, blow me down! Unfortunately, after the rocket picked up steam, ya bilge rat, shiver me timbers, me bucko, 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. Avast, me proud beauty!

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. Blimey! Oh, well. Arrr! Blimey! It was fun makin' t' rocket and t' initial D12 flights were really cool. Well, blow me down! T' E9 did not have enough initial thrust for a good flight. Aye aye! Aye aye! 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. Ya scallywag! It is kind o' like a stretch Fat Boy and about t' size o' a Big Daddy. Begad! Begad! T' swin' tests were quite positive and I am certain t' flight characteristics will be quite, well, interesting.

Finished

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

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