Scratch Solar Rail Original Design / Scratch Built

Scratch - Solar Rail {Scratch}

Contributed by David Hoffmeier

Manufacturer: Scratch
(Design this Spaceship Submission - by David Hoffmeier - 10/12/06)

Brief:

This be t' second rocket I built t' enter t' EMRR Spaceship Design Contest. Begad! Arrr! Blimey! Havin' never built or flown a rin' fin rocket this challenge proved to be exciting. I chose various materials for its construction includin' balsa wood, aircraft plywood, arrr, and dowel rods just t' name a few.

Characteristics:

  • Height: 27 7/8 inches Width: 4.6 inches Weight (without engine): 2.25oz
  • Motor Mount: 18mm (single) Recovery: Parachute
CLICK ON ANY PICTURE TO ENLARGE
Solar Rail

<--- This is a link to
the pattern for
the solar panel.

Characteristics
Height: 29.4"
Width: 4.56"
18mm Motor Mount
4.0 oz empty

 

Construction:

T' followin' are t' major components used:

  • Nose Cone
  • Parachute
  • Shock Cord with Paper Mount
  • 15.5" Body Tube (BT-50 )
  • 1" Body Tube (BT-50 )
  • 6" Body Tube (BT-20)
  • 6" Body Tube (BT-5)
  • 0.5" Body Tube (BT-60)
  • Four 1" x 5/8" Dowel Rod
  • Plenty o' 3/32" Square Balsa Rod
  • 1/32 Aircraft Plywood
  • 3/32 Birchwood plywood
  • Various Centerin' Rings
  • Engine Stop
  • Launch Lug

Narrative:

I broke this rocket down into three sections and tackled each one separately. Ahoy! Arrr! I began with t' tail section. Begad! I wanted t' create a mock up before I started cuttin' t' wood pieces. Avast, me proud beauty! First I sketched a design I liked on a piece of mate board. Begad! (I get scrap pieces from t' local frame shop.) Usin' that pattern, ya bilge rat, I cut four stanchions out o' t' mate board and glued them t' a scrap piece BT-20 tube. Aye aye! Begad! I constructed both rings out o' cardstock and attached them to stanchions. Arrr! A roll o' maskin' tape and a heavy cardboard tube served as my forms. Blimey! Well, shiver me timbers, blow me down!

I liked t' overall look o' this mock up. Aye aye! Ya scallywag! I even created t' lower paper transitions you see on t' finished rocket. Ahoy! T' only change be shortin' the BT-20 tube by a half inch. Actual construction o' t' tail end took much longer to create than expected. Ya scallywag!

I removed one o' t' stanchions and used it as a template on t' wood. Begad! Avast! I rough cut t' wood and used double sided tape t' stack t' birch plywood in four layers. Avast! Well, me hearties, blow me down! Followin' t' template on top, I cut and sanded them t' size. Avast! Avast! Then I glued them t' t' 6" BT-20, me bucko, with t' bottom o' t' stanchion even with the bottom o' t' tube.

I cut 1 - 5/8" and 2- 1 ¼" strips from t' 1/32 Airplane plywood. Well, arrr, blow me down! Blimey! Usin' steam on t' outside I began t' carefully curl t' strips into smaller circles. Avast, me bucko, me proud beauty! Blimey! Bein' very careful nay t' kink t' wood, I placed t' 5/8 strip inside t' heavy cardboard tube I had used earlier. Ahoy! Blimey! I curled t' 1 ¼ strip t' t' inside o' a tape roll. Begad! Blimey! Avast! Blimey! Leavin' them alone, I began work on t' mid section frame.

I took some graph paper and taped it t' t' table top and drew out t' frame work. Begad! Arrr! After a few sketches, arrr, I determined t' outside edge o' each square should measure 1 ½ inch. Begad! Begad! With 10 squares, matey, t' frame length ended up bein' 15 3/32". Ya scallywag! I placed a piece o' clear transparency over t' graph paper and began t' construct t' frame usin' t' graph paper below as a guide. I constructed two sides and then began t' join them usin' t' same method.

I looked online for a solar panel design and didn’t find one I liked or that closely resembled t' photo. Arrr! I used t' photo program on me computer and generated me solar panel design. Printed it on a color printer and cut it to size t' fit inside t' frame and allow a body tube t' go up t' middle.

I debated on usin' either a BT-20 or BT-50 tube through t' mid section. Ahoy! I finally decided on a BT-50 for t' inside tube. This selection will allow for the larger parachute. Aye aye! I had t' create a square with a circle cutout t' be placed in t' top o' t' frame as t' center t' inside tube. Avast, me proud beauty! Arrr! T' lower portion is supported by t' lower assembly. Avast! Blimey!

Now for t' upper assembly, me bucko, workin' from t' nose down, matey, I started with PNC-60. Avast! I cut off everythin' 3/8" below t' shoulder. Blimey! I glued a ½" section o' BT-60 t' t' nose cone. Well, blow me down! Aye aye! I created a centerin' rin' out of mate board for a BT-5 tube. I glued this rin' inside t' BT-60 tube. I pushed t' BT-5 tube through t' hole t' t' tip o' t' nose and glued it in place. I created and glued on a paper transition. Arrr!

Next I took a 1" section o' BT-50 with a BT-5 centerin' rin' glued in one end and placed over t' BT-5 tube and centered it over t' previous transition. Ahoy! I created two paper ½" transitions t' go from t' BT-50 to t' BT-5. Ya scallywag! (T' same transition is used under t' barrels.)

T' barrels were created with four 1" pieces o' 5/8 dowel rod. Ahoy! Blimey! Once glued together, me hearties, I began t' drill out t' center with increasin' drill bit sizes. Well, blow me down! Begad! Blimey! When I was close, me hearties, I used a rat tail file t' center t' hole and allow the BT-5 tube t' pass through. Though I made t' transition for under the barrels I did nay glue it on at this time. Arrr! Blimey! I glued a small nylon cord around the upper, arrr, mid, matey, and lower sections o' t' barrels.

I also used a piece o' dowel rod t' create a plug that would fit inside a BT-5 on one end and a BT-50 on t' other.

 

Paintin' o' t' rocket was done in sections. Begad! Ahoy! Blimey! Final assembly occurred after paint.

  1. T' barrels had t' added detail o' small nylon cord around them in three places. Avast! Once in place t' barrels were painted tan, and later trimmed with dark brown. Avast, me proud beauty! Well, blow me down!
  2. T' frame was painted metallic silver.
  3. T' remainin' rocket was painted gloss white. Avast, me proud beauty! Blimey! Begad! Blimey!
  4. T' silver and black accents were added later.

Once t' paint was dried, matey, I assembled t' upper section first. I attached the barrels with a little wood glue and added t' lower transition. Begad! I hand drilled a small pilot hole in t' wood plug for t' eye screw. Begad! I glued a BT-50 couplin' rin' t' t' plug, shiver me timbers, me bucko, and then I attached t' plug t' t' BT-5 tube.

Before attachin' t' mid section t' t' lower assembly I inserted t' paper solar panels inside t' frame. Avast, me proud beauty! I scraped off t' paint where t' lower assembly and frame would meet. Avast! I glued t' frame at t' four points on t' lower assembly and around t' tube at t' top. Avast! Ya scallywag! I wanted t' make a better fit and a stronger connection at t' top, so I attached a center rin' (which I first painted silver).

It be at this point I realized I didn’t have a launch lug. Ya scallywag! Once I figured out where I wanted it, arrr, I painted it t' match and attached it with white glue.

I wanted t' test this in some rocket software but wasn’t sure how to put in a square body with all t' other detail o' this rocket. Avast! Blimey! Avast! Blimey! I tried t' do a swin' test and could nay get t' rocket t' fly straight. Begad! Blimey! Ahoy! Blimey! Usin' RockSim I created t' rocket as though it had large smooth body tubes. Aye aye! Blimey!

In me design, me hearties, RockSim said I had an over stable rocket o' 3 something. Avast! Well, me hearties, blow me down! Blimey! To counter this I created forward fins ¾" tall and 1 ½" in length. Ya scallywag! Blimey! This modification brought me stability t' 1.8. Avast, me proud beauty! Well, blow me down! Blimey! T' keep with t' ring fin design o' t' rocket I added a ½" paper rin' t' t' fin tips. This brought me stability down t' 1.1. Arrr!

I created this new rin' fin t' attach t' t' rocket but nay permanently. Avast, me proud beauty! I still wanted t' keep t' original look o' rocket like t' photo. Aye aye! These fins are only attached for flight (like t' Saturn IV rocket, ha-ha). Ya scallywag! They were made usin' a ¾" BT-55 tube, balsa, centerin' rings, and ½" cardstock paper ring.

This fin slides on t' body tube just above t' frame. Ya scallywag! I conducted t' swing test again with this fin on and it flies straight, backwards. Ahoy! Uggghhh. Blimey! Avast, me proud beauty! I’m just goin' t' launch it and see what happens.

Date

Motor

Ejection / Altitude

Wind

Notes

10/26/06

C6-3

Just before / 150

12

No damage

10/30/06

C6-3

Just before / 140

17

Landed on roof, scuffs, arrr, matey, no damage

10/30/06

C6-3

Just before / 140

17

No damage

I haven’t launched t' Solar Rail with t' forward rin' attached. Arrr! Avast, me proud beauty! I wanted t' get three launches in without t' ring. Avast, me proud beauty! I’ll add t' rin' for a fourth launch when these winds die down. Avast! Blimey! This rocket has taken some hard hit and survived. Begad! I may build a larger 24mm version, after I see how others built theirs. Maybe I’ll be able t' pick up some ideas I hadn’t thought of and that wouldn’t be t' hard.

Launch1 Launch 2

This was an awesome contest. Well, blow me down! I hope you do it again in t' future. Blimey! Ya scallywag! Good luck to everyone!

FLIGHT #1

FLIGHT #2

FLIGHT #3

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