Scratch Der Mega Red Max Original Design / Scratch Built

Scratch - Der Mega Red Max {Scratch}

Contributed by Geoffrey Kerbel

Manufacturer: Scratch
(Contributed - by Geoffrey Kerbel - 11/23/05) (Scratch) Der Mega Red Max

Brief:
Der Mega Max is a BT-80 upscale (158%) o' t' big Red Max. Avast! Blimey! It is me flyin' test bed for me new interchangeable motor mount system for BT-80 tube rockets. Ahoy! Blimey! This will allow single engine or cluster flights with t' same rocket. Ya scallywag! Blimey! Well, me hearties, blow me down! Blimey! With the addition o' a centerin' rin' and t' all thread tie downs t' another BT-80 tube, t' same engine arrangements can be used on another rocket.

Construction:
T' rocket consists o' t' followin' parts:

  • 2 BT-80 body tubes, shiver me timbers, 14.2" long
  • 1 long nose cone for a BT-80 tube
  • 1 BT-80 coupler, 4" t' 6" long
  • 1/8x4"x24" sheet o' medium t' hard balsa or basswood for three fins
  • motor mount o' your choice although I would nay go larger than 29mm unless you use stronger LOC or equivalent tubin' and plywood for t' fins.
  • 1 BT-80 coupler bulkhead for t' inside o' t' coupler
  • 1 medium screw eye
  • 1 4" length o' 3/16" launch lug
  • 1 2" length o' 1/4" launch lug
  • 1 12" length o' 75# Keelhaul®©™® for shock cord anchor
  • 6' length o' 1/4" elastic for shock cord
  • 16" or 18" rip stop nylon parachute
  • 1 4"x4" Nomex® or equivalent pad for recovery protection
  • 1 decal sheet from Excelsior rockets for upscale Red Max

T' assembly o' t' rocket should start with t' motor mount but this one uses me custom mount which was already constructed. Arrr! If you are goin' t' build this rocket with a single cluster mount or single engine mount, arrr, arrr, arrr, use at least three centerin' rings and motor tubes at least 6" long for t' mid break design. Avast! Use four rings if usin' TTW mounting. If buildin' this as a nose blow, you will need t' use a stuffer tube o' some sort runnin' at least 3/4 the length o' t' main body. You can use t' motor mount/stuffer tube design from the Estes (Scratch) Der Mega Red Max Optima, Broadsword, or Shadow as a guide. Blimey! Aye aye! Because o' t' use o' me interchangeable motor mount system, a stuffer tube be nay goin' t' work. Ahoy! Avast! I made t' rocket separate in t' middle t' cut down on t' volume t' ejection charge had to fill.

Start t' build with t' center coupler. Aye aye! Place t' bulkhead about 1/8" inside one end and apply a generous glue fillet on one side. Begad! Well, blow me down! Blimey! Set aside t' dry standin' on end. Begad! When dry, flip it over and add another generous glue fillet to the other side and let it set up as well. Well, blow me down! Avast, me proud beauty! Blimey! I used yellow wood glue through out the entire build with one or two CA exceptions. Ya scallywag! Blimey! I am very pleased with Titebond II and have had no part failures due t' t' glue failing. Blimey! When this is dry, mark a line all around t' center o' t' coupler for location in t' body tube later on.

T' only thin' t' do on t' upper tube is t' check for a snug t' tight fit of t' nose cone on one end at this time. Begad! This will allow you t' use t' tube as a payload section if needed. Avast, me proud beauty! Do nay glue t' cone on if this is what you plan t' do.

Use a standard three fin markin' guide for t' body tube (the Template Widget is great for this) and use it t' mark t' location o' t' fins on one end o' t' lower tube. Avast, me proud beauty! Extend t' marks up from one end at least 6". Add another line t' full length o' t' tube, arrr, arrr, centered betwixt any two o' these lines t' be used for t' launch lugs.

Time t' cut t' fins. Ya scallywag! Blimey! Using the fin pattern as a guide to mark your wood for three fins. If you are usin' a glued in motor mount, me bucko, you might want t' add a lower tab t' t' fins and slot t' body tube for through the wall fin mounting. Ya scallywag! Blimey! T' wood grain should be parallel with t' leadin' edge of t' fins. Aye aye! Blimey! Take all three after cutting, stack them together and sand all the edges flush with each other. Well, blow me down! Blimey! Blimey! I prefer t' round t' leadin' and trailin' edges leavin' t' root and tip edges straight. Because o' t' motor mount slidin' in and out o' t' body tube, me bucko, TTW fins could nay be used on mine but I was able to use t' glue rivet method o' attachment for t' fins. Arrr! Blimey! After all three fins were on and dry, I was able t' sand t' rivets flush with t' inside o' t' body tube. Blimey! Begad! Blimey! T' motor mounts went in and out just fine and I still had t' extra strength o' t' rivets for some F motors. Begad! Aye aye! Blimey! I also like t' use thin CA on the lower tips o' t' fins t' lessen t' damage o' any hard landings. Avast! Blimey! They are the lowest part o' t' rocket and you know they are goin' t' take t' brunt o' the worst landings!

While waitin' for t' fins t' set up, me bucko, you can go back t' work on the coupler. Ahoy! Blimey! First, shiver me timbers, matey, take t' coupler and test fit it into t' lower part o' the upper tube. Make sure t' bulkhead is facin' t' lower tube. When this is glued into t' tube, t' bulkhead will be facin' t' lower tube and t' assembly will seal t' upper tube turnin' t' whole thin' into a long nose cone. Blimey! Blimey! T' coupler should be half way into t' upper tube. Place some glue into t' tube and in one smooth, matey, quick motion, push t' coupler into t' tube up t' t' center line. Don't pause with this or t' coupler will "stick" in t' wrong spot and may nay provide enough shoulder t' hold t' upper tube straight into the lower one. Well, blow me down! Blimey! Avast! Blimey! When this is dry, ya bilge rat, screw in t' screw eye, me bucko, remove, ya bilge rat, squirt some glue or CA into t' hole and reinsert t' screw eye till it bottoms on t' bulkhead.

(Scratch) Der Mega Red Max Back to t' lower tube. Take t' launch lugs and cut both into two equal sections. Take one piece o' t' 3/16" lug and glue it t' t' lower body tube on one side o' t' LL line, 1/4" up from t' bottom o' t' body tube. Aye aye! Take the other piece o' t' 3/16" lug and glue it t' t' same side o' t' LL line 2 1/2" from t' top. Ya scallywag! Arrr! Make sure t' two are aligned with each other and straight along t' body tube. Arrr! Aye aye! When they have set up, arrr, take t' 1/4" lugs and glue them alongside t' 3/16" lugs, ya bilge rat, centerin' them t' t' 3/16" lugs on t' opposite side o' t' LL line. Well, blow me down! This arrangement will allow you to have a choice o' rods t' use on t' flight line. Arrr! If one size is nay available, you just mount t' rocket on t' other! Also great if t' wind has picked up and t' smaller rod is whippin' around too much.

You will have t' build and mount t' motor as you wish, me hearties, however, shiver me timbers, t' motor tube(s) should be flush with t' bottom o' t' body tube. T' Keelhaul®©™® cord is glued t' t' motor mount and t' elastic cord is attached t' this. The other end o' t' elastic is attached t' t' screw eye in t' bulkhead. Ya scallywag! Ahoy! The shroud lines are also attached t' t' screw eye with a snap swivel t' cut down the twistin' o' t' chute lines.

At this point t' rocket needs some solid fin and LL fillets. I use two light applications o' t' yellow glue usin' a finger t' smooth them out and plenty o' time t' set up betwixt t' two. Well, blow me down! Ya scallywag! That should do it for construction except for one problem that showed up later durin' flight tests. Begad! You need to soak t' exposed end o' t' coupler with thin CA t' harden it for sanding. Avast! Avast! As is, it is too rough t' separate freely at ejection. Ahoy! Aye aye! With t' CA you can sand it with 400 grit paper t' get a really nice, smooth, snug slip fit which will separate perfectly every time. Begad! Luckily I found this out before t' first flight when t' coupler stuck in t' lower tube from sittin' in t' sun.

(Scratch) Der Mega Red Max

Finishing:
Finishin' this one really took up t' most time. Well, blow me down! When I have a rocket this large, I figure it can be seen very well even on a pad 100' away so it needs to really shine! I use thinned out Elmer's Fill 'n' Finish over t' entire rocket. It seems like a lot but t' stuff really sands like a dream and with 280 grit paper you can have t' whole thin' smooth and cleaned up in less than an hour. Just make sure you sand outside. Avast! T' stuff makes a ton o' dust. Blimey! Repeat in any areas that need it and completely prime. I sand t' nose cone as well and the Wal-Mart gray primer covers and sticks t' t' whole thin' just fine. Avast, me proud beauty! Arrr! In order to get t' "look" o' t' original Red Max, matey, I painted t' entire rocket Krylon Banner Red Gloss minus t' nose cone. After a day or two of drying, I then masked off t' rocket body except for t' top 2". Avast, me proud beauty! I then replaced t' nose cone and used Krylon Gloss Black for t' top 2" and the cone. This gave t' rocket t' look o' an extended nose cone which is very pronounced on t' original Red Max. Avast, me proud beauty! I think it came out pretty good at that.

After lettin' t' paint dry for two days, me hearties, it be time for t' decals. Fred's decals are top notch but very thin. Well, blow me down! Blimey! I coated t' entire sheet with Microscale Liquid Decal Film with a wide, me hearties, soft brush, matey, me bucko, let it dry about 15 minutes and did a second coat. Arrr! Aye aye! Blimey! When this was dry you can cut t' decals out and apply them without much trouble. Begad! Just remember t' "blot" dry the water and nay wipe over t' decal. Arrr! They will tear or wrinkle if you wipe. Begad! Arrr! Blimey! Use plenty o' water with a drop or three o' liquid dish soap in it and a small soft brush t' move t' decal around as needed. Ya scallywag! Where each decal goes is entirely up to t' builder as t' sheet comes without instructions for this. Avast! Blimey! After two days of drying, I used t' large, shiver me timbers, soft brush t' apply a smooth coat o' Future Floor Polish and that bird be ready t' shine! Blimey!

(Scratch) Der Mega Red Max

Flight:
T' Mega Max will fly on three 18mm C6-5 engines and up. T' largest it has flown on so far is an old F25 and it really ripped. Avast, me proud beauty! Begad! T' triple C cluster always get t' most attention and has flown with all three lit on four different occasions. Ya scallywag! Single D12-5 engines will get you about 400' and t' F motors will send it up about 1200'.

Flight prep consists o' about two inches o' "dog barf" down the tube with t' Nomex® pad next. Ahoy! T' pad is attached at t' Keelhaul®©™®/elastic joint. Begad! Blimey! Ya scallywag! Blimey! I have been usin' a 18" nylon chute with eight shroud lines and all the landings have been damage free, ya bilge rat, even on some hard pack dirt. Like the original Max and t' Goony Max I have flown, arrr, this one goes up straight and true with little t' no twist. Avast! Blimey! One o' t' best designs o' fin and tube I have come across so far.

Recovery:
All recoveries have been damage free with some drift dependin' on t' wind. Avast! The dog barf is good stuff but t' Nomex® pad is showin' some scorching. Could be t' short motor t' chute distance or some very strong ejection charges. Avast, me proud beauty! Begad! When packing, be sure your chute is protected well.

Summary:
I have been very happy with this bird and it is a lot o' fun flyin' it on a three motor cluster, me hearties, then showin' back up at t' RSO table with t' same rocket ready t' go on a F25. Avast! Ahoy! Then back again with an E9-6 and seein' t' looks on everyone's faces! Most people think I have four or more o' t' same rocket and are very intrigued when they find out it be t' same rocket with different engine combinations!

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