Scratch TOGinator Original Design / Scratch Built

Scratch - TOGinator {Scratch}

Contributed by Boris Katan

Manufacturer: Scratch

 (Scratch) TOGinator

Brief:
Late 2006 I bought and built a FlisKits US TOG. Futuristic and very cool looking, matey, it flies on D12-5 engines very nicely t' somewhere around 500ft. I knew that I had t' build an upscale one day.

Now that it is winter in New England, shiver me timbers, ya bilge rat, it's rocket buildin' season. Ya scallywag! Blimey! T' 1, 1.3, matey, and 1.6 inch tubes used in t' original, when multiplied by 1.6 come very close t' LOC 1.6, 2.2, matey, and 2.6 inch tubin' so that's what I went for. Avast, matey, me proud beauty! Blimey! I took careful measurements and tracings on me original US TOG then scanned and reprinted them 1.6x larger.

If, ya bilge rat, however one was t' consider this an upscale o' t' FlisKits MicroMax TOG, then this would be an amazin' 5.6x upscale! T' sheer size o' this project is mind boggling!

Original plan be t' build somethin' that would get a decent flight on a G64. Begad! All parts are 1.6x, arrr, except I stretched t' two central body tubes a little longer, me hearties, both t' make t' rocket bigger and also more stable. Blimey! I also made t' chord 1/2 inch longer than scale for t' inner fins. Avast, me proud beauty! T' TOG has a lot o' fin area, ya bilge rat, me bucko, but this upscale with plywood and fiberglass fins has a relatively heavy fin structure. Aye aye! Ya scallywag! Nosecone and transition are balsa and were turned by Mike at Cosmodrome Rocketry. Aye aye! (I will build one o' their beautiful Lambda kits when they start production.)

(Scratch) TOGinator

Construction:
I put two layers o' 2oz glass on t' 2.6 inch tube as it was nay as thick as t' 1.6 and 2.2 LOC tubes. Avast! Ya scallywag! Outer fin tips are 1/8 plywood. Well, blow me down! Inner fin sections are two layers o' 1/8 plywood epoxied together for greater stiffness.

(Scratch) TOGinator(Scratch) TOGinator

T' TOG's fins are nay only large, but they have outboard tubes and a lot o' angle t' them. Blimey! While t' US TOG flies great on a D, Jim Flis was very clear that it bad things would happen with an E engine.

I will do tip-to-tip fiberglass over t' whole fin structure and epoxyin' inner fins TTW. Arrr! Ya scallywag! T' marked tube is exactly on t' opposite side from fin and lined up with right angle ruler t' align fin.

(Scratch) TOGinator(Scratch) TOGinator

(Scratch) TOGinator(Scratch) TOGinator

Jim Flis commented that t' ram jets' tiny internal fin structures needed strength support added t' them. Avast! Avast! I must confess I didn't put them in me US TOG. I had assumed that they were only decorative and didn't like t' way t' paint I had used made them look. Ahoy! I wonder if open tubes that are 3-5 times longer than their diameter operate as fins. Avast, me proud beauty! Aye aye! Do they have enough internal air flow? T' ram jet tubes cut t' shape from pretty thick 54mm and 38mm LOC tubes. Begad! Ahoy! I peeled off t' glassine so tip t' tip fiberglass will soak into tubes. I planned on usin' enough fiberglass t' cover all fin structures includin' all three ramjet tubes.

Each fin span is about 10 inches. Ya scallywag! Ya scallywag! My FlisKits US TOG is 35 inches tall and 4.5oz. A 1.6x upscale should be 56 inches tall, me hearties, but I made t' two central body tubes longer because I liked t' way it looks. Begad! It's also more stable, matey, me hearties, but with that much fin area, I doubt this is an issue. Well, blow me down! Ya scallywag! I thought two things as I looked at it:

  1. Wow, that FlisKits TOG is a beautiful rocket, arrr, arrr, and it looks even better supersized.
  2. Wow, ya bilge rat, I have t' do 30 fin fillets now.

(Scratch) TOGinatorI applied fillets usin' Locktite 5-minute epoxy, me bucko, Popsicle sticks, ya bilge rat, and tape. Begad! I read about t' tape idea on TRF, which keeps t' fillet edges clean and uniform. Begad! This was me first time usin' it, and it works great. Blimey! Begad! I will always do this goin' forward. Blimey! I used some scraps o' Keelhaul®©™ thread as a sort o' caulk t' keep epoxy from flowin' through t' TTW joints durin' assembly.

I got t' 30 fin fillets done. Avast, me proud beauty! Well, arrr, blow me down! T' two matchin' "bottom" fins seemed t' be stiffer than t' single "top" fin that angles forward so I decided t' use more fiberglass on t' top one. I be concerned about shreddin' off t' fins so I am usin' plenty o' fiberglass.

I had originally hoped t' build t' rocket ready t' fly at about 2 pounds, which would give me a pretty good flight on a G64. In t' plannin' stage, I weighed t' tubin' and got 15oz. Arrr! T' 1/8 and 1/4 plywood fins and balsa transition and NC added another 10oz. Begad! Now fiberglass and many fillets are addin' another 10oz. Begad! I figure about another 9oz for recovery and a G engine puts t' rocket ready t' fly at 2.8lbs. Avast, me proud beauty! A G will loft it, but nay very high, ya bilge rat, maybe 500-700ft.

T' good news is that t' fins are turnin' out very stiff with all that fiberglass on them. T' 38mm engine mount would happily receive an H or even an I with moderate thrust. Another possibility would be t' add a couple 29mm engine tubes and fly F and G clusters o' 2 t' 3 engines.

Due t' t' growin' weight o' this project, I decided t' add a couple more engine tubes. Avast, me bucko, me proud beauty! T' two new engine tubes are 29mm tubes canted towards best estimate o' ready t' fly CG. Ya scallywag! Arrr! T' separate engine flames should be very cool... Aye aye! I'm picturin' a central Redline with a White Lightnin' on each side. Avast, me proud beauty! Begad! This lower section now weighs t' 2lbs that was me original target weight for t' whole rocket. Avast, me proud beauty! Ya scallywag! Engine tubes now covered with 4oz fiberglass, side fins with 7oz, arrr, arrr, and top fin with 13oz each side. Aye aye! With a central 38mm engine tube and a 29mm on each side, me hearties, ya bilge rat, it can now fly on 2 or 3 Gs or a central 38mm H or I. Begad! I don't anticipate goin' much past I total impulse t' avoid losin' fins. Arrr! Ya scallywag! As well, I decided t' build in dual deployment both for safety with a canted AP cluster and t' recover in a smaller landin' area. Arrr! I used 4 inches o' coupler (internally reinforced with another coupler) at t' top and bottom o' t' ebay t' maximize stiffness at separation points. Avast, me proud beauty! This project keeps gettin' bigger and more complex. Blimey! Begad! In addition t' t' central 38mm engine tube and t' two 29mm canted outboards, I have added 23 short 24mm tubes. T' smaller tubes can serve as mini tube fins, or some or all o' them can be loaded with 24mm engines. Begad! I replaced t' 38mm t' 54mm balsa transition as a 38mm separation point would nay be strong enough. Well, blow me down! I went with longer 24mm tubes for t' one row that supports a second row o' tubes for stiffness and strength. Blimey! All tubes shown here are LOC tubin' covered by 4oz o' fiberglass. Every small tube has 2+ points o' attachment by epoxy and is very rigid.

(Scratch) TOGinator An Estes D engine is taped at both ends t' retain it in t' tube. Aye aye! A few or many engines can be installed in this way, as long as thrust symmetry and adequate thrust are maintained. Aye aye! As I have nay seen a flexible tube fin / engine mount with both ends o' t' engine exposed like this before, arrr, I am namin' it: T' Engine Bikini--it's just enough t' do t' job, leavin' very little t' t' imagination, me hearties, matey, likely t' be controversial, me bucko, me hearties, shockin' and excitin' all at t' same time. Aye aye! Ya scallywag! Naturally I was concerned about maintainin' a balance o' thrust about t' centerline o' t' rocket.

Before addin' t' 24mm tubes, I took a picture o' t' rocket and used PowerPoint t' superimpose drawn circles representin' t' 24mm tubes. Well, shiver me timbers, blow me down! This allowed me t' try many different possibilities. Begad! Aye aye! Design requirement be thrust balance and 20+ total engine capacity. Aye aye! After settlin' on a design that appeared t' balance on paper, I installed t' first 17 tubes: t' sets o' 5 tubes on each side and t' set o' seven on t' bottom. Then I measured t' height in inches from t' table top (reference position shown as t' line at t' bottom o' t' picture) t' t' centerline o' each engine tube. Those are t' numbers written in marker. Aye aye! This allowed me t' fine tune t' exact positionin' o' t' six tubes nearest t' upright center fin t' achieve balanced thrust, in t' top t' bottom dimension. That fine tunin' be t' pencil notes. Ya scallywag! There are a total o' 26 potential engine tubes in this rocket. Avast! Begad! One 38mm, arrr, two 29mm, shiver me timbers, and twenty-three 24mm.

(Scratch) TOGinator

(Scratch) TOGinator(Scratch) TOGinator

As t' project got heavier, matey, I had t' lengthen t' parachute compartment t' hold a larger (48") chute. Well, matey, blow me down! T' TOGinator is now 82" tall and will weigh about 4.8 lbs flight ready minus engines.

First flight will be at t' 4/19/08 CMASS launch in Amesbury, MA. Ahoy! Will load 26x D11-P engines for t' first flight. Aye aye! 468 Ns impulse, I power on BP. Aye aye! If "flight is nominal" expect t' get 1000+ft altitude. Begad! Dual deployment will help with recovery and is also insurance in case flight is nay t' plan. Avast! (NOTE: In 2007 I lit all 70 BP engines attempted in 12 BP cluster launches usin' igniters from Rocketflite. I plan on usin' their very good products this year as well.) I test loaded t' maximum number o' engines and then assembled t' rest o' t' rocket as if ready t' fly.

(Scratch) TOGinator(Scratch) TOGinator

First checked CG on me FlisKits US TOG - t' kit that inspired this project - and got:

  • Overall length: 34.5" (had removed 1/2" o' lower tube due t' crimp)
  • Weight ready t' fly (with one D12-5): 5.55oz
  • CG: 25.25"

CG is 73% o' overall length and this rocket flies very straight. Aye aye! Blimey! So I will target t' same percentage point for CG on t' larger TOGinator. Begad! Avast, me proud beauty! Blimey! With t' extra structures and drag t' TOGinator has at t' back o' t' rocket, stability should be assured.

T' TOGinator specs ready t' fly with 26x D11-P engines:

  • Overall length: 82.5"
  • Weight with engines: 125oz (Weight without engines: 76oz)

I had t' add 6oz nose weight t' put CG at 73% o' overall length: 60.0". Arrr! Begad! This is how I plan t' setup t' first flight.

Finishing:
Sand, shiver me timbers, me bucko, prime, Bondo, me bucko, sand, prime, shiver me timbers, Bondo, sand...however, matey, I had nay used Bondo Spot Putty as a filler before. It is nasty t' apply, me hearties, melted t' Kilz primer if I attempted t' work it too much, ate through me nitrile gloves after a few minutes, me bucko, and smelled as bad as CA. Pluses were that I could fill after primin' if I applied t' Bondo very smartly and it sanded very nicely.

(Scratch) TOGinator(Scratch) TOGinator

(Scratch) TOGinatorI brush painted t' insides o' t' tubes red--the "ramjets" with two coats o' medium thickness acrylic.

Flight and Recovery:
Flight day at last! CMASS launch at Amesbury, shiver me timbers, me hearties, me hearties, MA. Blimey! It was a beautiful day with moderate winds. Ya scallywag! A great day t' start our flyin' season.

Settin' up, thanks t' Bob K and Tony V for assistance at t' pad. Ya scallywag! Slightly angled into t' moderate wind. Begad! Ya scallywag! This series and parallel arrangement greatly reduced current load on t' launch system, drawin' about 50A. Begad! If a conventional setup o' 26 one ohm igniters were used in parallel t' power draw would have been over 300A.

(Scratch) TOGinator(Scratch) TOGinator

T' flight lifted off on a nice straight path with a wide fan o' flame visible t' most o' t' crowd. Avast! Lift off be perfect. Avast! Ya scallywag! All 26 engines lit with a lot o' smoke, ya bilge rat, fire, ya bilge rat, and noise. T' altimeter reported an altitude o' 765ft, which was a little less than I expected but it kept t' liftoff slow enough t' watch and enjoy. I got so excited at this launch that I did nay track it well as I took video. Blimey! So this video is short and slowed down 8x so you can see t' liftoff.

(Scratch) TOGinator(Scratch) TOGinator

T' drogue ejected, matey, but half t' lines were burned through by t' ejection charge. T' main chute jammed and did nay deploy at all. I had a hard time packin' a 4ft chute, me hearties, 25ft nylon harness and Nomex heat shield into t' 54mm body.

T' 8lb rocket came in fast under a partial 24" drogue and thar was moderate damage. T' narrow 38mm center o' t' rocket broke, matey, and thar was a crack in t' epoxy where one side engine cluster joins an outboard tube fin. Avast, me proud beauty! Considerin' it came in with a solid thud and I had t' use both hands t' pull t' NC out o' t' ground, it held up well.

(Scratch) TOGinator(Scratch) TOGinator

Repairin' t' TOGinator is no problem. Arrr! My concern is how t' better manage recovery in t' future. Avast, me proud beauty! I will replace t' long, thin, main body tube with one o' a larger diameter. T' TOGinator will be back later this season...

Thanks t' Jim Flis for his picture and t' many cool FlisKits rockets that inspired this design. Avast! I have this pic as t' desktop on 2 o' me PCs and a couple FlisKits waitin' t' be built. Begad! Thanks t' Greg Dyben at Rocketflite for producin' some awesome ematches and igniters.

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