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. Aye aye! Havin' never built or flown a rin' fin rocket this challenge proved to be exciting. Ya scallywag! I chose various materials for its construction includin' balsa wood, shiver me timbers, shiver me timbers, aircraft plywood, 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. I began with t' tail section. Aye aye! I wanted t' create a mock up before I started cuttin' t' wood pieces. First I sketched a design I liked on a piece of mate board. Avast, me proud beauty! Avast, me proud beauty! (I get scrap pieces from t' local frame shop.) Usin' that pattern, me bucko, I cut four stanchions out o' t' mate board and glued them t' a scrap piece BT-20 tube. Avast, me proud beauty! I constructed both rings out o' cardstock and attached them to stanchions. Begad! A roll o' maskin' tape and a heavy cardboard tube served as my forms. Begad!

I liked t' overall look o' this mock up. Begad! Blimey! I even created t' lower paper transitions you see on t' finished rocket. Well, blow me down! T' only change was shortin' the BT-20 tube by a half inch. Well, blow me down! Avast! Actual construction o' t' tail end took much longer to create than expected. Blimey! Ya scallywag!

I removed one o' t' stanchions and used it as a template on t' wood. Blimey! I rough cut t' wood and used double sided tape t' stack t' birch plywood in four layers. Blimey! Begad! Followin' t' template on top, me bucko, I cut and sanded them t' size. Aye aye! Arrr! Then I glued them t' t' 6" BT-20, 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. Ya scallywag! Ya scallywag! Usin' steam on t' outside I began t' carefully curl t' strips into smaller circles. Begad! Bein' very careful nay t' kink t' wood, I placed t' 5/8 strip inside t' heavy cardboard tube I had used earlier. Ahoy! Begad! I curled t' 1 ¼ strip t' t' inside o' a tape roll. Avast! 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. Aye aye! After a few sketches, I determined t' outside edge o' each square should measure 1 ½ inch. With 10 squares, ya bilge rat, t' frame length ended up bein' 15 3/32". Ahoy! 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. Avast, me proud beauty! 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. Ya scallywag! Well, blow me down! I used t' photo program on me computer and generated me solar panel design. Ya scallywag! Arrr! 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. Begad! I finally decided on a BT-50 for t' inside tube. This selection will allow for the larger parachute. Well, blow me down! 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. Begad! T' lower portion is supported by t' lower assembly. Avast, me proud beauty!

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

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. Ya scallywag! I created two paper ½" transitions t' go from t' BT-50 to t' BT-5. Arrr! (T' same transition is used under t' barrels.)

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

 

Paintin' o' t' rocket was done in sections. Ya scallywag! Avast, me proud beauty! Final assembly occurred after paint.

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

Once t' paint be dried, arrr, I assembled t' upper section first. I attached the barrels with a little wood glue and added t' lower transition. I hand drilled a small pilot hole in t' wood plug for t' eye screw. Begad! Begad! I glued a BT-50 couplin' rin' t' t' plug, 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! Avast! I scraped off t' paint where t' lower assembly and frame would meet. Avast, me proud beauty! Well, blow me down! I glued t' frame at t' four points on t' lower assembly and around t' tube at t' top. Ahoy! Well, arrr, blow me down! 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, matey, 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. I tried t' do a swin' test and could nay get t' rocket t' fly straight. Avast, me proud beauty! Blimey! Usin' RockSim I created t' rocket as though it had large smooth body tubes. Arrr! Blimey! Ahoy! Blimey!

In me design, RockSim said I had an over stable rocket o' 3 something. Well, matey, blow me down! To counter this I created forward fins ¾" tall and 1 ½" in length. This modification brought me stability t' 1.8. Ya scallywag! 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. Aye aye! Blimey!

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

This fin slides on t' body tube just above t' frame. Avast! I conducted t' swing test again with this fin on and it flies straight, backwards. Aye aye! Aye aye! Uggghhh. 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, 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. Ahoy! I wanted t' get three launches in without t' ring. Ya scallywag! I’ll add t' rin' for a fourth launch when these winds die down. Well, blow me down! This rocket has taken some hard hit and survived. I may build a larger 24mm version, after I see how others built theirs. Avast, me proud beauty! 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 be an awesome contest. Ya scallywag! Ya scallywag! I hope you do it again in t' future. Arrr! Good luck to everyone!

FLIGHT #1

FLIGHT #2

FLIGHT #3

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