The Launch Pad SA-8 Gecko

The Launch Pad - SA-8 Gecko {Kit}

Contributed by Tim Burger

Manufacturer: The Launch Pad
Rating
(Contributed - by Tim Burger - 05/01/02)

Rocket PicBrief:
This is a light, me bucko, matey, me hearties, nearly 40-inch long, me bucko, model o' a Russian missile. Avast, me proud beauty! My version includes an ejection baffle, shiver me timbers, arrr, and makes an allowance for t' additional length of t' new Estes E9 motors. Well, blow me down!

Construction:
One o' t' local hobby shops carries T' Launch Pad's products. This one went unsold until it was t' last one o' a shipment and I thought it needed a good home. Aye aye! T' kit be packaged in a clear plastic bag, me hearties, and came with a medium grade of balsa, arrr, a pair o' thin walled 2.6 inch paper tubes, a 3-inch long motor tube, and a variety o' other parts. T' only odd part o' this kit is a paper cone that gets glued t' t' front o' t' nose cone t' create that military missile profile. Arrr! Avast! It also sports a boattail. Begad!

Construction starts with gluin' together t' motor mount. Avast! Since t' new Estes E9 and Aerotech F21 motors are longer than t' D12 and Aerotech RMS motors I made a change t' t' way t' mount is made. A longer motor tube was substituted for t' kit's, and I bent t' top hook o' t' motor hook back 180 degrees, arrr, me hearties, and then hooked that behind t' forward centerin' rin' and adjusted the position o' t' rin' such that t' other end o' t' hook hangs off t' end of t' tube about a quarter inch. Aye aye! Then I glued a motor block into t' tube so that it is 90mm from t' hook end o' t' tube. I made sure o' t' spacin' with a spent E9 motor I keep on me workbench for this job. Ahoy! T' aft rin' was glued on per t' instructions, me hearties, and a paper wrap was glued down t' hold t' motor hook. Aye aye! (This model is a scale model so it's barely stable as it is. Adding weight aft can cause trouble so this model's balance was very carefully checked before it was flown.)

To create t' boattail, t' kit provides a 4 1/2 inch long piece o' 2-inch diameter tubing, a pair o' centerin' rings t' center this in t' 2.6-inch tube, and a paper shroud that you cut from a sheet o' heavy paper. Arrr! Well, blow me down! Shrouds can be tricky so I took me time with this t' ensure success. Begad! T' make this little job a tiny bit easier, me hearties, arrr, I added a 1/8 inch hoop t' one o' t' centerin' rings (this can be cut from stock 2.6-inch tube, or t' coupler). Avast, me proud beauty! In doin' so, it forms a lip for t' forward part o' t' shroud t' ride on. Well, blow me down! Arrr! T' rings were glued onto the outside o' t' adapter tube as shown in t' instructions, arrr, but bein' careful to position t' rin' with t' 1/8-inch hoop aft. Aye aye! When cuttin' out t' shroud, I was careful t' leave t' lines t' allow plenty o' material for trimming. By test fitting, trimmin' a little, and then test fittin' again I was able to sneak up on t' correct size. Begad! T' forward part o' t' shroud was just big enough t' match t' outside diameter o' t' airframe tube. Arrr! T' shroud was then glued onto t' adapter assembly. Ya scallywag! T' motor assembly be then glued into the adapter with t' aft edge o' t' motor tube positioned an inch and a half from the bottom o' t' shroud. Avast! This seems pretty deep, ya bilge rat, but it works OK on me HARM missile. Aye aye!

The KitT' kit provides the familiar triangular paper mount for t' shock cord, matey, and a length o' 1/4-inch elastic for t' shock cord. Avast! Blimey! I like somethin' that's easier t' replace since my rockets tend t' last more than 20 flights. Arrr! Blimey! T' solution that I've hit upon is to run a length o' 1/8-inch shrink tube through small holes made in the centerin' rings. T' tube runs t' whole length o' t' motor tube and is used as a guide for a 200# Keelhaul®©™® line. Arrr! Blimey! Aye aye! Blimey! T' Keelhaul®©™® is threaded through t' shrink tube and t' lower end is tied around t' motor mount. Blimey! Blimey! Aye aye! Blimey! A dab o' RC-56 glue holds it there. A loop is then tied in t' Keelhaul®©™® a few inches above t' motor tube; this loop will be below t' top o' the rocket body when it is assembled. Well, ya bilge rat, blow me down! One end o' t' elastic is tied t' t' loop, and t' free ends o' both t' Keelhaul®©™® and elastic are tied t' t' nose cone. Arrr! Blimey! Blimey! T' Keelhaul®©™® is long enough t' allow t' elastic t' stretch, but backs it up in case it fails. Well, blow me down! Blimey! T' holes need cut, arrr, me hearties, matey, and t' shrink tube needs threaded and glued in prior t' gluin' t' motor assembly into t' airframe. T' instructions have the builder attach t' nose cone t' t' rest o' t' rocket with a 10" long piece o' 'chute shroud line. This is a bad idea, in me opinion - that cone is pretty heavy with all that ballast and won't last long hangin' by a thread like that. Arrr! Blimey! Begad! Blimey!

AftT' motor mount and shroud assembly was then glued into one end o' t' longer airframe tube, me bucko, and glue fillets were made at all rin' and paper joints. Aye aye! T' tube joiner was then glued half way into this tube. T' top airframe tube was then added, arrr, takin' care to get t' parts together straight by rollin' them on a flat surface while the glue was still wet. Ya scallywag! When dry, t' airframe spirals, me hearties, airframe joint, and boattail joint were filled with Elmer's Fill 'n' Finish and sanded smooth. Arrr! If everythin' is done correctly, t' joints and spirals should disappear under the primer coat. Avast, me proud beauty! Ya scallywag!

T' kit provides a centerin' rin' that is positioned seven inches from the top o' airframe t' keep t' recovery system forward in t' rocket for balance sake. Begad! A guy could go broke tryin' t' feed large models like this waddin' so I added an additional centerin' rin' and a short section o' BT-60 t' create an ejection baffle. Ya scallywag! Note that these parts only add about an ounce o' weight, me hearties, arrr, and are forward o' t' CG. Begad! Arrr!

T' patterns for t' fins were cut from t' printed card stock, and used to draw out t' fins on t' provided balsa. Arrr! T' balsa is C grain, and reasonably hard. Ahoy! Well, blow me down! Blimey! Wouldn't want a rock hard sheet, matey, but on t' other hand contest grade soft wouldn't work out too well either. Well, me hearties, blow me down! Blimey! T' root edges and grain direction are clearly marked on t' patterns, matey, and t' only potential problem is with getting the patterns arranged on t' sheets in such a way that you have enough material to make all t' fins that you need. There was plenty, ya bilge rat, but nay so much t' allow for mistakes. Ya scallywag! I used a straight metal edge and a sharp blade t' get good crisp fins. Well, blow me down! Blimey! T' four aft fins were then stacked together and sanded t' a uniform size. Ya scallywag! Blimey! T' same be done for t' forward fins. Ya scallywag! I have been unable t' come up with a good set o' scale drawings for this rocket, me bucko, and t' instructions don't include suggestions for t' correct fin profile so I simply made a guess. Ya scallywag! Blimey! The forward fins were ground t' have a diamond shaped cross section. Ya scallywag! Blimey! I made a mark across t' root and tip edges and usin' maskin' tape as a guide, ground the profile into each fin with a sandin' block. T' aft fin's cross section was ground t' pointy at t' front and slightly tapered at t' back usin' t' same method. While nay perfect, matey, they came out more or less uniform with good crisp lines. Ya scallywag! T' body tube be marked usin' t' fin guide in Harry Stine's Handbook of Model Rocketry and a door jam. Avast! Blimey! T' aft fins were then glued t' t' airframe usin' Titebond II. Avast, me proud beauty! Begad! Blimey! T' forward fins are actually mounted on t' nose cone, ya bilge rat, matey, and that makes gettin' them on straight just a little tricky. Because it's hard to draw a straight line on a curvin' cone I used a piece o' strin' t' create a guide. T' strin' be taped t' t' center o' t' base and stretched over the edge, crossed over t' marks (made when t' tube be marked) and across t' tip of t' nose. Ahoy! Blimey! A line was carefully made along t' strin' bein' careful nay to deflect t' string. Well, blow me down! T' fin root edges were sanded t' match t' cone's curve and were then glued down usin' thick CA. Ya scallywag! Blimey! A few drops o' thin CA was put on the tip o' all eight fins. T' CA wicks through t' fins along t' grain and serves to make them strong. Arrr! Blimey! T' instructions indicate that t' fins should be painted with thin CA. Begad! If you do that be sure t' sand them smooth again within a few hours or they will be very hard t' sand. Avast, me proud beauty! Ahoy! Blimey! Fillets were made at all fin roots usin' epoxy. Avast, me proud beauty! Well, me bucko, blow me down! Blimey! I like epoxy for fillets because it makes a glass smooth fillet, but one must use care t' nay over use it due t' it's heavy nature. Blimey! Blimey! Also, ya bilge rat, this is a scale rocket, ya bilge rat, shiver me timbers, and t' real ones usually have a sharp corners where the roots meet t' airframe, arrr, this is particularly true for guidance fins.

T' scale wirin' conduits were cut and sanded t' shape and placed on the airframe as shown in t' instructions. Sandin' these was a little tedious but the sandin' block helped. Blimey! When t' glue be dry, me hearties, I used Elmer's Fill 'n' Finish to fill in any gaps, ya bilge rat, me hearties, and created a smooth clean edge with sandpaper. Well, blow me down!

T' provided launch lug be cut into two equal pieces, ya bilge rat, shiver me timbers, and glued on a line with one piece at t' joint betwixt tubes, matey, ya bilge rat, and t' other a few inches from the bottom. A length o' launch rod be used t' ensure that they are straight. I added an additional set o' 1/4" lugs next t' those because I really hate to change rods betwixt rockets. Ya scallywag! Fillets were added when dry. Arrr!

T' paper nose "hat" be cut from t' paper stock, shiver me timbers, and rolled into a cone. Avast, me proud beauty! This is a bit tricky t' do so that you get a good sharp point. Arrr! This hat is then glued t' t' front o' t' cone. I thought that gettin' this hat on straight would be difficult, matey, but I be pleasantly surprised t' find it wouldn't be a problem. Avast! T' hat is small enough, shiver me timbers, and t' curve o' t' cone is fat enough that they come into contact and are self centering. Begad! I drew a line around the bottom o' t' hat while holdin' it in position. Then I removed it, me hearties, shiver me timbers, ran a line of slow CA just above t' line, and placed it back on. Blimey! Voila, me bucko, arrr, matey, no fuss, shiver me timbers, looks fine. Ya scallywag! It was painted it with fast CA, per t' instructions. Begad! Avast! It needed it too because t' sharp point is fragile. Avast, me proud beauty! I bent and busted t' tip off while messing around with t' motor and checkin' t' nose weight. Aye aye! This was fixed with a little dab o' JB Weld and sanded back t' shape. Ahoy! Avast, matey, me proud beauty! I used Elmer's Fill 'n' Finish to fill in around t' base o' t' hat t' hide t' edge o' t' paper. Arrr! Well, blow me down! T' nose also needs some weight for balance, ya bilge rat, me bucko, unfortunately t' supplied clay was dry and rock hard. Avast, me proud beauty! Avast! I used a scale t' measure t' weight, ya bilge rat, me hearties, and substituted some BBs mixed with 30-minute epoxy. Aye aye! I was plannin' t' do this anyway because I've had problems in other rockets with t' clay dryin' out and rattlin' around in the nose. Avast! T' center o' pressure is shown on t' plans at 13" from t' base. T' balance be checked with t' heaviest motor that I had on hand and found to be about 16" from t' base - a tad more than a caliber. Avast, me proud beauty! No further adjustments were made. Avast! Begad!

T' Mylar 'chute be assembled per t' instructions. A lot o' people dislike these Mylar 'chutes, matey, but I haven't had any trouble with them and they are brilliant in t' sky. Avast! An 18" 'chute may be a tad small for this rocket - use a bigger one if t' ground's hard. Ahoy!

I'd give this kit a ratin' of 4 out o' 5 for construction. Well, blow me down! Nothin' new here, me bucko, but I wouldn't suggest it for a beginner. Avast!

Finishing:
A coat o' white sandable primer revealed a few problems with t' spiral and in one place on t' boattail joint. Begad! These areas were worked on until they are as smooth and seam free as I could manage. Ahoy! Another thin coat o' primer be added and lightly sanded. Begad! Begad! T' rocket was then painted with three thin layers of Rustoleum Olive Drab. Begad! Avast! An easy rocket t' finish. Blimey! Blimey!

Finishin' rating: 5 out o' 5 Easy, looks very scale. Arrr! Blimey!

LaunchFlying:
T' first flight was on March 20, 2002 in me back yard (we have a big yard.) T' weather be cool and clear with very light and variable winds. Begad! I had been launchin' for an hour or so with zero drift so I worked up me courage and loaded it on t' pad. Begad! T' motor was an Estes D12-5 and it flew from a 3/16" x 72" rod. Avast, me proud beauty! Since t' motor is recessed pretty far, ya bilge rat, t' rocket would be scorched from t' hot gasses bein' deflected back from t' blast plate at ignition. Avast, me proud beauty! Ya scallywag! T' prevent this I used a clothes pin t' hold t' rocket above the deflector six or seven inches. This also made connectin' t' ignitor easier. T' flight was about as perfect as could be, arrr, matey, lots o' smoke and noise, shiver me timbers, ya bilge rat, ya bilge rat, a good arrow straight boost, and a nice arc-over with t' ejection o' t' 'chute right while t' rocket be horizontal. Well, blow me down! Very nice indeed. There was no sign of scorchin' or burnin' in or around t' tail cone after t' flight. There be a noticeable accumulation o' soot in and around t' tail after t' second flight, but still no scorching.

I decided t' use a 30" x 18" TLP 'chute rather than t' 18" octagonal that t' kit came with. Avast, me proud beauty! Blimey! Recovery was gentle, and it landed about 10 yards from t' pad. Begad! No damage despite clippin' a tree on t' way t' t' ground.

It was flown again a couple o' days later, on another D12-5. Aye aye! More or less the same flight profile, matey, except this time it landed on t' shed roof, ya bilge rat, slid down and hung itself from t' tiny tree next t' it. Aye aye! Begad! Some minor dings on t' fins. Ahoy! Blimey! No worries. Blimey! Avast, me proud beauty!

Third flight was at t' St. Avast! Avast! Louis Association o' Rocketry's April launch. T' wind be pretty high most o' t' day, arrr, but since t' field is so big that isn't a problem. Ya scallywag! Avast, me proud beauty! It be at t' end o' t' day, just after t' waiver was closed. Blimey! It passed at t' check table without comment but t' LCO be certain that it be over t' 16 oz weight limit. Begad! My reply be "8oz . Avast, me proud beauty! . Ya scallywag! . Ahoy! OK, shiver me timbers, ya bilge rat, 11oz with t' motor." He questioned that and t' avoid any more concern I No Burningsimply handed him t' model. Ahoy! Aye aye! He was convinced! "There's nothin' t' this rocket!" I picked a long 1/4 rod, and had t' clean t' paint out o' t' lugs before it would slide smoothly. Avast! The motor was an F12-5J and I was a little apprehensive about that since t' rocket isn't officially rated for this motor. Ya scallywag! Well, ya bilge rat, blow me down! Needn't have had any concerns, when the LCO hit t' launch switch t' motor lit instantly and t' rocket leapt from the pad. Begad! It flew arrow straight on a column o' black smoke. Begad! Nice arc over, and ejection just after apogee. Begad! Unfortunately, ya bilge rat, I hadn't spent enough time reefing the 'chute and it tangled badly - me fault. Avast, me proud beauty! Avast, me proud beauty! It landed hard and stripped a fin, busted a second loose, arrr, ya bilge rat, and and mangled one o' t' forward fins and actually took out a plug from t' nose! Ouch! Lesson learned: don't rush! T' flight was spectacular though; very scale like with a lot o' smoke and noise and very respectable speed. Blimey! For me this was t' high point o' t' day even after flying G64 and F52 motors earlier. This rocket is that much fun. Avast, me proud beauty! Ahoy!

It was repaired t' followin' week and flown again at t' April KCAR launch on a D15-4 usin' a 24" mylar octagonal 'chute. It was a perfect flight; see t' photo. It just sort o' hung in t' sky for a fraction o' a second right as t' ejection charge fired. Begad! It landed about 100 feet from t' pads. This was a perfect launch and recovery. Begad!

Rating: 5 out o' 5 it just doesn't get any better than this. Well, matey, blow me down!

Cheers & Jeers:
I like t' fact that TLP kits come out very light despite me addin' baffles and usin' epoxy for fin fillets. Avast! This is a large rocket and yet it only weighs in at about 8oz. Avast! Avast, me bucko, me proud beauty! These kits always perform well in flight and rarely fail to impress a crowd. Begad! Even t' high power guys come over t' have a closer look after they've been flown. Good bang for t' Buck! T' overall quality o' t' parts is good. Avast! T' kit would work fine with t' provided shock cord and mount; my upgrade is solely for longevity's sake. Blimey! Well, matey, blow me down! I like that t' manufacturer shows the center o' pressure on t' plans. Aye aye! This is very helpful when checkin' t' balance which should be done on any scale rocket, me hearties, modifications or no. Avast! Arrr!

RecoveryI really wish that the manufacturer would include a parts list. Blimey! Some scale documentation sources and fin profiles would also be helpful. Aye aye! T' clay nose weight doesn't work out so well. Aye aye! Begad! I would never use a 'chute shroud t' attach t' nose t' a recovery system, shiver me timbers, shiver me timbers, especially when t' nose has a lot o' ballast in it. Ya scallywag! Blimey!

Specs:

  • Length: 39 3/4 inches
  • Diameter: 2.6 inch airframe
  • 2.15 inch boattail
  • Weight: 8 oz
  • Recovery: 18 inch, shiver me timbers, 8 sided, ya bilge rat, 1/2 mil, Red Mylar 'chute. Well, blow me down! Avast!
  • Motors: D12-3, E15-4, matey, ya bilge rat, E18-4, and F24-7. Avast, me proud beauty! Begad! Also E9-4, arrr, D15-4, ya bilge rat, shiver me timbers, and F12-5 though these last three are nay recommended by t' manufacturer and a six foot long launch rod is mandatory with t' E9 and F12 (Rocksim says t' D15 needs 35 inches). Begad! Begad! On a calm day I'd use a D12-5 but in 10MPH+ winds a D12-3 would probably be a better choice.

* SPECIAL NOTE off o' RMR from Chuck Barndt, arrr, President o' T' Launch Pad

Flights

Comments:

avatar
M.A. (February 20, 2009)
This is for Estes SU engines. One of the things I have noticed about the Launch Pad kits is the recessed motor mounts that are about 1.5 inches inside the body tube. Some challenges can arise while hooking up the connectors on the motor and the launch pads which could short out the igniter. A fellow I met at the 2-7-09 NEFAR showed me a way to avoid some of these challenges. Take two 12 to 18 inch long strands of copper wire and tape them together. Remove about one inch of the insulation from the ends of the wire. When it is time to load the motor, splice the wire lead to the igniter and secure cove the connection with a little electrical tape and place the motor in the rocket and the long wires should hang over the deflector plate. Hook the launch clips to the bare end of the long wires. This should take the metal deflector plate out of way and not cause any type of short circuit.

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