Manufacturer: | Scratch |
CONCEPTION & DESIGN NARRATIVE:
When out shopping, ya bilge rat, I usually scan t' toy isle lookin' for Bail Out payload
candidates. Ahoy! Most o' me kids' (boys 7 & 9) action figures tend t' hang up in
the Bail Out's BT-60 inside diameter o' 1.595" (41 mm). Well, me bucko, blow me down! A couple o' months
ago, arrr, shiver me timbers, while at me local Big Lots, I saw these little foam gliders. They are
packed two t' a card for $0.99. Begad! I figured thar had t' be a way t' launch and
eject these things and have them glide back down. T' kids ought t' get a kick
out o' t' little gliders loopin' through t' sky. Avast, me proud beauty! Arrr!
Without any idea o' what t' use t' launch them, shiver me timbers, I didn't buy them. Aye aye! I be in the middle o' a scratch built sport scale (1:154) Saturn V at t' time and didn't want t' start somethin' new. Once t' Saturn V was done, I started thinkin' o' t' gliders for me next project. Arrr! Arrr!
T' gliders are called Super Tuff Mini Shots Stunt Gliders. Begad! Blimey! They are made in China for Just Toys, arrr, Inc. o' New York, me bucko, NY. Ahoy! Blimey! Blimey! They are intended t' be used in Mini Shots guns. These appear t' be comparable t' t' Nerf guns that shoot mini darts. Ya scallywag!
T' body o' t' glider is yellow foam, me hearties, me bucko, approximately 0.67" (17 mm) in diameter, 4 3/8" (111 mm) long, with a 3/16" (5 mm) diameter hole up t' back. Ya scallywag! T' glider has white foam semi-delta wings, similar in shape t' t' Space Shuttle; approximately 3" (76 mm) at t' root edge and 1 3/4" (44 mm) at t' trailin' edge. Blimey! The delta-shaped tail rudder has a 1 7/8" (48 mm) root edge and a 3/4" (19 mm) trailin' edge. Arrr! Ya scallywag! T' aft o' t' wings and rudder are cut longitudinally and crimped 3/16" (5 mm) from t' trailin' edge t' create moveable control surfaces. Begad! A few minutes spent with each resulted in relatively flat spiral flights that will stall, drop a bit, shiver me timbers, and spiral some more. Aye aye!
T' first idea for a launch vehicle be a large diameter rocket with the gliders ejected from within t' body tube with t' parachute. With t' glider's approximate 4" (100 mm) win' span, matey, arrr, this was smartly ruled out. Ya scallywag! Aye aye!
T' second idea was "strap-ons" with an ejection-triggered strap release. Blimey! I considered a slotted main tube with straps connected t' some type of piston assembly, me hearties, but that seemed too complicated. Ya scallywag! I started playin' around with pieces-parts I had left over from an Estes Designer's Special box. Ahoy! I found a 4 1/32" (103 mm) piece and a 12 5/8" (320 mm) piece o' BT-50. Avast, me proud beauty! These looked good together with t' short piece at t' bottom. Aye aye! Well, blow me down! T' I.D. Well, blow me down! Ahoy! o' BT-20 at 0.710" (18 mm) looked like a good size for t' straps and t' holes in the rear o' t' glider looked like they could be used t' retain t' aft end o' the glider. Aye aye! There be a 4 1/8" (105 mm) long PNC-50 in t' Designer's Special box, arrr, and two 2 7/8" (73 mm) long PNC-20s. Well, blow me down! Blimey! T' base airframe was set. Begad!
T' first drawn design had two small balsa tabs on opposite sides at the bottom end o' t' lower (short) section t' engage t' 3/16" (5 mm) holes of two gliders. Avast, me proud beauty! Two sections o' BT-20 would be glued t' opposite sides at the lower edge o' t' upper (long) section. Avast! Arrr! T' BT-20 straps would be topped with PNC-20s. Arrr! I reconsidered t' use o' t' PNC-20s. Arrr! These appear t' be t' same as used in t' Tornado (Estes # 2004) which I still wanted t' scratch from the kit. Ya scallywag! I next considered card stock fairings. A few days later I figured, shiver me timbers, heck, untopped straps will virtually guarantee separation while a capped tube may create a little vacuum and delay or prevent proper separation. Ya scallywag! T' straps were sized at 3/8" (10 mm). Aye aye! Ya scallywag! I don't know why other than they looked good. Ahoy!
I know what you're thinking: "Hey, matey, this looks just like t' Estes A.R.V. Begad! Condor" (Estes #2075). Aye aye! Well, me hearties, blow me down! It is similar, ya bilge rat, but this is cheaper than the A.R.V. Avast! (US $13.29 list), plus thar be a local source for cheap replacement gliders. Big Lots has a ton o' these.
T' first stability check was run in VCP. T' noses o' t' gliders were treated as a transition section. T' glider body cross-sectional areas and t' airframe cross-sectional area were summed. Avast, me proud beauty! An effective diameter be calculated based from this sum. Avast! Blimey! T' glider wings were entered as 4 delta-shaped fins. Begad! Aye aye! T' tail rudders were ignored. Begad! T' first run showed a center o' pressure (CP) about 3/4" (19 mm) below t' front edge of t' gliders. Avast! Aye aye! This looked good. Begad! Blimey!
Even though t' CP looked good, I was concerned with t' lack o' fin area along t' axis through t' gliders (perpendicular t' t' gliders wings). T' relatively small tail rudders were t' only "fins" in this axis. To add fin area in this axis, t' small balsa tab idea was turned into a flat-top fin like this:
This configuration wasn't analyzed in VCP, but it has t' be better (lower CP).
T' final configuration is shown in t' photographs below:
PARTS LIST (as-built, see SUGGESTED
MODIFICATIONS below):
Lower Section:
4 1/32" (103 mm) BT-50
Standard Estes Engine Mount (18 mm)
3/32" (2.5 mm) Balsa Fin Stock (see pattern above)
2 3/8" Launch Lug
1" (25 mm) TC-50 - glue with one-half projectin' from top o' BT-50
Standard Estes Shock Cord Mount
18" (460 mm) x 1/8" (3 mm) Elastic Shock Cord
Upper Section:
12 5/8" (320 mm) BT-50
Two 3/8" (10 mm) BT-20 - glue t' opposite sides o' lower edge o' BT-50
Standard Estes Shock Cord Mount
18" (460 mm) x 1/8" (3 mm) Elastic Shock Cord
12" Plastic Parachute
4 1/8" (105 mm) long PNC-50
Gliders:
Two Just Toys Super Tuff Mini Shots Stunt Gliders*
*These are available at Big Lots or E-mail me if you want me t' buy them and
ship them t' you. Avast, me proud beauty!
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SUGGESTED ENGINES: | (feet) | (meters) | |
A8-3 | 200 | 60 | |
B4-4 | 500 | 150 | |
B6-4 | 400 | 125 | |
C6-5 | 700 | 200 | |
D12-5* | 1000 | 300 |
My name is Mark Recktenwald. Arrr! Avast, ya bilge rat, me proud beauty! I used t' fly rockets as a kid (between 11 and 15), shiver me timbers, ya bilge rat, and started up again about 8 years ago. Avast! Well, matey, blow me down! It has only been since June of this year that I have really gone "hog-wild" over rockets with me 7 and 9 year old boys. You may recognize me name from RMR. Arrr! Arrr! I usually post under "kentengr@raex.com".
This page was created on October 31, 1998. Avast, me proud beauty! Blimey! Arrr! Blimey!
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