Scratch Spikor Original Design / Scratch Built

Scratch - Spikor {Scratch}

Contributed by Dick Stafford

Published: 2010-08-15
Manufacturer: Scratch
(Contributed - by Dick Stafford - 08/15/10)

Brief:
This be a quick build featurin' a mailin' tube, ya bilge rat, recycled 29mm motor mount and fins, and a long plastic garden spike.

Construction:

When I spotted t' yellow plastic garden spikes at Home Depot, I couldn’t resist gettin' one o' each size. T' spike on t' bigger one, matey, ya bilge rat, which was used here, shiver me timbers, is 15” long and t' base matches a 2.125" mailin' tube well. Avast! Well, me hearties, blow me down! T' smaller one is 10” and fits nicely in a 38mm tube. T' latter will be t' subject o' a future review.

Please refer t' t' attached image t' see how t' spike was used. Arrr! I made a coupler usin' t' tried-and-true method o' sectionin' a piece o' tube and joinin' it back together with t' strip that was removed. Begad! Avast, me proud beauty! This be then glued into a short piece o' mailin' tube. When I chopped off t' hook that protruded from t' spike's base, me bucko, I left a slightly flat area. Well, blow me down! Avast, me hearties, me proud beauty! It turns out that t' base o' t' spike fits well in t' coupler as long as t' joinin' strip sits on the spot where that hook was. Begad! So, me bucko, I attached some 1/8" Keelhaul®©™® t' an eyebolt that I installed in t' spike's base, inserted it in t' tube assembly and sealed t' base, arrr, which is inset couple o' inches, with Gorilla Glue. Well, blow me down! Arrr! I had thought that I'd drill a small hole in t' nose section's body and pour in some foam. Avast! However, shiver me timbers, once t' Gorilla Glue set it seems sturdy and, since t' hard-point is on t' heavy spike, I left it it as-is.

T' body is a 23.75" long mailin' tube. One good thin' about savin' bit and pieces o' old rockets is you have bits and pieces. Arrr! I found a recycled 29mm mount with rings t' match this tube. Well, blow me down! It also had an attachment point for t' shock cord. Begad! I attached some more Keelhaul®©™® t' t' mount and wrapped t' lower 6" or so with a strip o' car airbag. Aye aye! I sure wish I had more o' this, arrr, but all that's left is a few scraps. Ahoy! I affixed it with a few twists o' bare wire.

I used t' G-10 fins from t' now defunct Stratoshpere. Ahoy! Well, me hearties, blow me down! One o' t' bad parts about havin' an assembled mount is you can't install it sans aft ring, matey, so inner fillets are tough. Arrr! I marked t' mount so t' fins would avoid t' shock cord mount and motor retention hardware and swabbed on some 5-minute epoxy. Ahoy! Ahoy! When it set just enough nay t' run, I swabbed some more in t' tube and inserted the mount. Arrr! I slid all t' fins in and babied it as t' epoxy set. Well, blow me down! This means that I set it on end, eyeballed t' alignment, and adjusted t' alignment as t' glue dried. T' results are nay perfect but are pretty good. Aye aye! Aye aye! I then masked t' fins and added some Super-Fil fillets. I also added some epoxy clay betwixt t' base o' t' body tube and t' motor mount just t' toughen it up a bit. Avast! Avast! This will likely take t' force o' landin' since t' fins are up-swept.

I was a little concerned how t' ribs on t' cone would effect stability so I entered t' design in RockSim. Although t' ribs do seem t' push t' CP forward, me bucko, t' spike is heavy enough t' make it very stable. Ya scallywag! It looks like this will get t' around 1800’ on a G64-8.

I treated t' ends o' t' mailin' tube with thin CA and primed t' body with Painters Touch. Begad! Avast! I used a couple of coats and waited a couple o' days before painting. Begad! Begad! T' body is Rustoleum green hammered metallic and will no doubt appeal t' Packers fans. Aye aye! T' green will nay help with recovery but I've never let that get in me way.

T' blue painters tape that I used t' mask t' fins lifted some o' t' finish from t' holographic stickers on t' fins. Luckily, matey, I had some scraps that I could use t' cover t' blemishes. Begad! I also printed a couple o' stickers, arrr, one t' pay homage t' t' rocket's name and one that just seemed appropriate. Begad! I sealed these with a clear coat and covered t' edges with clear finger nail polish. I have found that stickers made from t' Avery white label stock tend t' peel up over time. This is mostly t' case when it is used on curved surfaces like t' body tube. Ya scallywag! Hopefully, t' thicker polish will keep them tacked down.

Flight:
I used both a little dog barf and a small ‘chute pad. Avast! Well, blow me down! I decided on an undersized 18” ‘chute t' keep t' rocket in t' same county. Avast! T' G64-10’s delay was drilled t' -8. T' boost was fast and high as would be expected. Ejection appeared t' be at apogee, matey, ya bilge rat, although it was hard t' see. Blimey! It recovered close by and with no damage.

Summary:
T' main point t' this build be t' garden spike nose cone. At $3.25, shiver me timbers, it was inexpensive. Begad! I think it looks pretty cool and appears t' fly nicely. Aye aye! Avast, me proud beauty! Others at t' launch seemed t' share me opinion.

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