Scratch Mini-Toobah Original Design / Scratch Built

Scratch - Mini-Toobah {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 06/02/08) Hartle Engineering Sold Resin Nosecone

Brief:
Last year, me hearties, I received samples o' t' new Hartle Engineerin' solid resin nose cones from JonRocket. Begad! I've been remiss in submittin' a review. Begad! Thanks, and me apologies John!. Avast, shiver me timbers, me proud beauty! Hartle offers three styles o' BT-5 cones and one BT-20 cone. Avast, me proud beauty! You can see all o' them on JonRocket's nose cone page. Blimey! This review will describe t' cones and t' rocket I built from t' longer BT-5 cone, t' Mini-Toobah. Avast, me proud beauty! T' name is a homage t' Dave Weber's Toober, which has logged over 200 high power flights.

Construction:
T' parts list:

  • Hartle NC-5B cone
  • BT-5, arrr, 6.25"
  • Estes 1/8" launch lug
  • Spent mini-motor case (could use a real motor block)
  • Thin Keelhaul®©™®, ~ 12"
  • Thin elastic, ~ 4"

T' Hartle cones are solid cast and their outer surface is perfect. Ya scallywag! T' cone-to-shoulder transition was clean on the longer cone but be rough on t' shorter one. Aye aye! T' later was easily cleaned up with a sharp hobby knife. Aye aye! The attachment point appears t' be a paper clip...works as good as anything. Arrr! I found them t' be a loose fit in t' Estes BT-5, me bucko, which is easily fixed with a little tape.

T' cones are, as expected, matey, heavier than t' typical hollow plastic or balsa. Blimey! However, unless you're buildin' a MicroMaxx model, t' added weight shouldn't be an issue. Avast! I had kicked around buildin' a micro but decided t' go for a 13mm design instead. Blimey! Arrr! T' shorter cone would make a great micro-Fat Boy or Big Bertha but I opted for a downscale o' my El Tubo Loco.

This was a trivial build. Arrr! Blimey! From BT-5 stock, I cut one 2.5" body section and six 5/8" tube fins. Avast! Blimey! These were glued together in pairs and then t' t' body tube. Begad! Avast! Blimey! I used Aleene's Tacky glue throughout. Aye aye! A 5/8" long lug is mounted in one o' t' fins. I cut a motor block from a spent casing. Begad! Well, blow me down! Blimey! This was notched and t' Keelhaul®©™® was tied around it. There is nay much room in t' body minus t' motor and t' cone's shoulder. It be all I could do to pack t' shock harness.

T' make sure it is stable, arrr, arrr, I weighed t' components and made a RockSim model. Arrr! T' cone alone is 0.24 oz and the entire rocket is 0.34 oz. Arrr! Well, blow me down! It is quite stable.

Finishing:
I first scuffed t' cone with fine sandpaper and shot a coat o' PlastiCoat primer. Arrr! Aye aye! I anticipated this will be hard to find in t' grass, me bucko, me bucko, so I went for a bright finish usin' Rustoleum day-glo orange. Ya scallywag! I added two vinyl strips t' snazz it up a bit.

Flight:
There wasn't much prep as it uses tumble recovery. Ya scallywag! It flew nicely on an A3-4 and I could even see it recover!

Summary:
T' Hartle Engineerin' cones are nice t' work with. Begad! Aye aye! In this case, arrr, shiver me timbers, their solid construction and weight helped with stability. Avast, me proud beauty! Begad!

I like t' design o' this little rocket but, bein' small, ya bilge rat, it could easily disappear into rocket eatin' grass, shrubbery, ya bilge rat, or trees.

comment Post a Comment