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

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

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

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

Flight:
There wasn't much prep as it uses tumble recovery. Ahoy! 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. Avast! In this case, me hearties, their solid construction and weight helped with stability.

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

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