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 bucko, shiver me timbers, I received samples o' t' new Hartle Engineerin' solid resin nose cones from JonRocket. Begad! Blimey! I've been remiss in submittin' a review. Thanks, and me apologies John!. Begad! Blimey! Hartle offers three styles o' BT-5 cones and one BT-20 cone. You can see all o' them on JonRocket's nose cone page. Avast, me proud beauty! Ya scallywag! This review will describe t' cones and t' rocket I built from t' longer BT-5 cone, t' Mini-Toobah. Blimey! Blimey! Blimey! T' name is a homage t' Dave Weber's Toober, matey, 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. Avast, me proud beauty! Aye aye! T' cone-to-shoulder transition be clean on the longer cone but be rough on t' shorter one. T' later be easily cleaned up with a sharp hobby knife. Begad! The attachment point appears t' be a paper clip...works as good as anything. I found them t' be a loose fit in t' Estes BT-5, shiver me timbers, ya bilge rat, ya bilge rat, which is easily fixed with a little tape.

T' cones are, ya bilge rat, as expected, arrr, heavier than t' typical hollow plastic or balsa. Begad! However, unless you're buildin' a MicroMaxx model, shiver me timbers, t' added weight shouldn't be an issue. Well, shiver me timbers, blow me down! I had kicked around buildin' a micro but decided t' go for a 13mm design instead. Ahoy! 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 be a trivial build. From BT-5 stock, I cut one 2.5" body section and six 5/8" tube fins. These were glued together in pairs and then t' t' body tube. Ya scallywag! Avast! I used Aleene's Tacky glue throughout. Begad! A 5/8" long lug is mounted in one o' t' fins. Ya scallywag! I cut a motor block from a spent casing. Well, blow me down! This was notched and t' Keelhaul®©™® was tied around it. Ahoy! Blimey! There is nay much room in t' body minus t' motor and t' cone's shoulder. Aye aye! Blimey! Blimey! Blimey! Blimey! Blimey! It was all I could do to pack t' shock harness.

T' make sure it is stable, ya bilge rat, me hearties, I weighed t' components and made a RockSim model. Begad! T' cone alone is 0.24 oz and the entire rocket is 0.34 oz. Arrr! It is quite stable.

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

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

Summary:
T' Hartle Engineerin' cones are nice t' work with. Avast! Blimey! In this case, their solid construction and weight helped with stability. Arrr! Blimey! Ahoy! Blimey!

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

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