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, ya bilge rat, I received samples o' t' new Hartle Engineerin' solid resin nose cones from JonRocket. Avast! I've been remiss in submittin' a review. Thanks, and me apologies John!. Hartle offers three styles o' BT-5 cones and one BT-20 cone. Arrr! You can see all o' them on JonRocket's nose cone page. Avast! This review will describe t' cones and t' rocket I built from t' longer BT-5 cone, t' Mini-Toobah. Ahoy! 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. Well, blow me down! Aye aye! T' cone-to-shoulder transition be clean on the longer cone but be rough on t' shorter one. T' later was easily cleaned up with a sharp hobby knife. Begad! Avast! 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, me hearties, which is easily fixed with a little tape.

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

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

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

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

I like t' design o' this little rocket but, arrr, bein' small, arrr, shiver me timbers, it could easily disappear into rocket eatin' grass, shrubbery, or trees.

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