Scratch MicroMaxx Mega Pad Original Design / Scratch Built

Scratch - MicroMaxx Mega Pad {Scratch}

Contributed by Carl Tulanko

Published: 2010-08-18
Manufacturer: Scratch

Brief:

I have been flyin' MicroMaxx rockets with me kids for a long time now, matey, and through our endeavors, me hearties, me bucko, we have made many improvements in certain areas pertainin' t' t' MMX line. Avast, me proud beauty! One o' t' first changes we made was t' t' launch pad/controller; t' controller with a 9V battery was barely adequate for launchin' anythin' consistently, so we switched t' usin' me homemade HPR single launcher and adapted t' pads for this controller; it made a BIG difference! Somethin' else was still missin' though…I wanted a launch pad for all seasons, me hearties, available for launchin' scratch or kit rockets nay limited t' t' MMX launch rod. Aye aye! Avast! In addition, me bucko, I wanted a pad able t' supply enough current for clusters, along with t' ability t' “Drag Race” me models. Aye aye! Well, blow me down! Finally, matey, it had t' be elevated or provide an easy way t' install t' igniter in t' motor prior t' launch; crawlin' on t' ground tryin' t' get t' rocket down over t' igniter installed in t' Quest Pad be gettin' old. For these reasons, me hearties, I came up with what I feel is real close t' t' “Ultimate” in MicroMaxx launchers…I call it t' “MicroMaxx Mega Pad!”

 

Construction:
T' concept originally started out as a small wooden chair, matey, available at most stores for under $10. Begad! Blimey! However, I wanted somethin' bigger with t' capability t' store extra pads. Avast! Blimey! Eventually, t' chair I purchased was stripped o' it’s back and seat and used for t' “Legs” o' t' Mega Pad. I finally settled on a piece o' 1’ x 2’ white shelvin' board, available at any hardware store. Begad! Blimey! T' design had also incorporated a bottom cover plate, me bucko, made from 1/4" x 1" wood furrin' strips and a piece o' Plexiglas, me hearties, ya bilge rat, so I picked up two pieces o' 1/4" x 3", each 24" long and would cut 1" strips from them. Begad! Blimey! While I be still at t' hardware store, me bucko, I saw several pieces o' Plexiglas in t' “cutting” cage and one o' t' employees found me a piece, me bucko, cut it t' 12” x 24” and marked it “Scrap”…which in rocketeer terms means free! Blimey! Finally, arrr, I picked up a three foot section o' Pine 1 x 3 t' make t' pads. Total investment in wood, under seven dollars.

T' frame was easily constructed usin' t' materials listed above. Also note you could make your own usin' a large round seat and 3" x 3/4" circular bulkhead plates instead o' t' “square” design I used…the sky be t' limit.

T' hard part be comin' up with a modular design for t' pads and electronics. Avast! I settled on usin' DC power jacks in t' base and plugs on each pad. Avast, me proud beauty! Aye aye! Some 1/4" stainless steel rod be used opposite t' plug as an “alignment” pin for each pad. Begad! Gold coated fuse tabs were cut and used for igniter contacts and I used some #2 hex head aluminum screws t' mount each tab. Blimey! T' tops o' each pad were covered with a piece o' sheet aluminum I cut from a larger piece I got from t' hardware store. Aluminum and Pine were used because o' their ease t' shape and cut. As far as t' stainless pins go, shiver me timbers, me hearties, I cut them from a couple o' stainless “T” handles that were attached t' a pack o' ten “Remove before Flight” flags I won on t' ROL Auction last year; I always recycle and was able t' get about 3 pins per handle, each about 1" long. Ahoy! Ya scallywag! When finished, I had tons o' pads all built and kept one master block o' wood with holes drilled in case I wanted t' make more later down t' road.

Power jack locations were routed in t' bottom o' t' white shelf board and 12 gauge wire was run throughout. Aye aye! I designed t' board for 5 active pads in parallel at one time, arrr, t' fifth pad usin' two “posts” for cluster hookup. Begad! What is even nicer and an afterthought was, me hearties, shiver me timbers, since t' pad electronics were t' be built from me HPR design, arrr, t' “bindin' posts” at location five could also serve t' launch HPR rockets directly from t' pad, or t' “bindin' posts” could be directly hooked into someone else’s launch controller and t' MMX Mega Pad could be controlled by a club launcher. Blimey! Once finished with t' power jacks, me hearties, four additional locations were drilled along t' right side o' t' board for pad storage. Blimey! T' Plexiglas be epoxied t' t' 1" furrin' strips and this bottom “cover” be screwed into t' bottom o' t' main pad board.

All electronics parts, with t' exception o' t' RJ45 jacks, were obtained from me local Radio Shack and were used exclusively throughout t' design. Avast, me proud beauty! Blimey! T' pad controller uses a 30 amp relay t' directly switch battery power t' t' igniter. Power is supplied t' t' pad unit via an automotive battery; alligator clips with two 8 gauge wires connect t' t' battery, arrr, while t' other end plugs into two banana jacks on t' left side edge o' t' board; t' pad controller in turn supplies power t' t' hand unit. Blimey! Ya scallywag! This path is protected with a 30 amp glass fuse, in case o' accidental shorts. Ya scallywag! Also, a test button is incorporated into t' Pad Controller t' test t' relay for shorts (welded relay contacts) prior t' hookin' up an igniter…a very nice safety feature. Arrr! Power and Warnin' indicator LED’s are located on t' front o' t' Pad Controller, matey, t' Fuse is on t' left side, me bucko, t' 30 amp relay is in t' aft and an RJ45 Networkin' Jack is located on t' right. Begad! T' 8 pin RJ45 jack is connected t' t' hand controller usin' t' center four pins via a standard flat phone cable and plugs. Well, blow me down! On distances exceedin' 100', full eight conductor network cable is used t' “parallel” wire pairs for t' four control wires, which decreases loss in t' cable due t' it’s length. Arrr! All o' this be designed integral t' t' electronics. T' pad also has a piezo alarm for continuity, along with a continuity test button. Avast! There are several additional integral features designed in t' background for testin' and troubleshootin' t' units, matey, arrr, ya bilge rat, but these will nay be covered in this article.

T' Hand Controller has a power switch located on t' top left side and indicators on top include LED’s for Power, Continuity and Arm. Blimey! Ya scallywag! T' safety key switch was purchased from Aerocon, a great source for these items, matey, arrr, and I have used them on me L3 before with great success. Arrr! A momentary pushbutton is used for launch and t' four basic control wires run t' a RJ45 jack on t' top o' t' hand controller. Blimey! T' four wires supply 12 volts positive, 12 volts negative t' t' hand unit, me bucko, me hearties, along with continuity and fire t' t' pad controller. When powered on, shiver me timbers, a green power LED lights as does a yellow continuity LED as t' unit checks for continuity and t' piezo beeper can be heard at t' pad. Well, blow me down! Turnin' t' “ARM” key switch causes t' red Arm LED t' flash throughout t' remainder o' t' launch sequence. Aye aye! When t' fire button is depressed for launch, me hearties, ya bilge rat, t' beeper is bypassed and t' igniter fires.

T' pads themselves are very modular and allow you t' build a “fleet” o' launch surfaces; me pad types include a small tower, me hearties, medium tower, shiver me timbers, large cluster tower, matey, standard Quest two position rod, ya bilge rat, ya bilge rat, adjustable rod, 3 fin tower, me hearties, a Rail with Tower and a small cluster tower. Arrr! T' possibilities are endless and allow you t' try all different kinds o' launch methods; rods are no longer a must as I have had great success with t' tower pads. Usin' towers allows you t' now worry about installin' a launch lug and maintains a more realistic appearance for those “scale” models. Well, blow me down! 4-40 control rods are used for towers, ya bilge rat, while a rail was custom made from plastic bridge material and a square brass piece o' tubing. For rail buttons, I used HO racecar track pins found at most hobby stores; t' pin side was epoxied into t' model.. T' bottom o' t' pad has a 1/4" stainless alignment pin on one side and t' DC power plug on t' other. Avast, me proud beauty! A flat bladed screwdriver is used through t' bottom t' easily push out used Quest igniters. Ahoy! Arrr! In addition, arrr, t' contacts can be cleaned and tension can be adjusted before insertion o' t' igniter.

Flight:
T' best part though is rocket prep. I built a small “staging” stand that holds one modular Pad as I insert t' igniter and install t' rocket, shiver me timbers, all while I sit at me prep table. Arrr! Ya scallywag! T' Pad and rocket are taken out t' t' launch table assembled together, then plugged in an empty location and ready t' go…it’s that easy! No more crawlin' on t' ground, fightin' with t' igniter tryin' t' get it installed. Aye aye! Avast, me hearties, me proud beauty! Moreover, me hearties, I have incorporated a “Quick check” continuity tester built in t' t' prep/stagin' stand, me hearties, so you know you have continuity before you take t' pad t' t' table.

Summary:
In summary, me bucko, me bucko, t' MicroMaxx Mega Pad is a great project t' build and a blast t' use. Well, blow me down! Blimey! After buildin' it, shiver me timbers, I have a hard time tryin' t' remember how we used t' launch them. T' guys at our local NARRRRR club also enjoy that pad and it is thar at all t' launches I attend. Begad! Blimey! Also, me hearties, t' pad has encouraged me t' build several scratch models, which would never have come t' pass if I was still usin' t' old system. Well, blow me down! Blimey! Begad! Blimey! I have included schematics and pics, along with a LINK t' me album containin' step by step build photos. Begad! Also. Begad! you can send an email if you have any questions regardin' t' pad design or construction; as a matter o' fact, arrr, me hearties, I still have a few sets o' labels for t' pad and hand controllers that are printed and free t' t' first couple users. Well, blow me down! In t' meantime, I will try t' get a parts list together for t' pad and provide a link t' t' labels for each controller. If you decide this is for you, go ahead and build one o' these Mega Pads…you will nay be disappointed!

 

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