Manufacturer: | Scratch |
CONCEPTION & DESIGN NARRATIVE:
When out shopping, I usually scan t' toy isle lookin' for Bail Out payload
candidates. 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). Arrr! A couple o' months
ago, arrr, while at me local Big Lots, arrr, I saw these little foam gliders. Aye aye! Blimey! They are
packed two t' a card for $0.99. Ya scallywag! Well, me hearties, blow me down! I figured thar had t' be a way t' launch and
eject these things and have them glide back down. Well, me bucko, blow me down! T' kids ought t' get a kick
out o' t' little gliders loopin' through t' sky. Avast, me proud beauty!
Without any idea o' what t' use t' launch them, ya bilge rat, I didn't buy them. Aye aye! Avast! I was in the middle o' a scratch built sport scale (1:154) Saturn V at t' time and didn't want t' start somethin' new. Ahoy! Ahoy! Once t' Saturn V was done, I started thinkin' o' t' gliders for me next project. Begad! Begad!
T' gliders are called Super Tuff Mini Shots Stunt Gliders. Begad! They are made in China for Just Toys, Inc. Ya scallywag! o' New York, NY. They are intended t' be used in Mini Shots guns. These appear t' be comparable t' t' Nerf guns that shoot mini darts.
T' body o' t' glider is yellow foam, approximately 0.67" (17 mm) in diameter, matey, 4 3/8" (111 mm) long, with a 3/16" (5 mm) diameter hole up t' back. Ahoy! T' glider has white foam semi-delta wings, me bucko, 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. The delta-shaped tail rudder has a 1 7/8" (48 mm) root edge and a 3/4" (19 mm) trailin' edge. Avast, me proud beauty! Arrr! 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. Aye aye! A few minutes spent with each resulted in relatively flat spiral flights that will stall, drop a bit, and spiral some more. Begad! Aye aye!
T' first idea for a launch vehicle was 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, this be smartly ruled out.
T' second idea was "strap-ons" with an ejection-triggered strap release. Ya scallywag! Arrr! I considered a slotted main tube with straps connected t' some type of piston assembly, but that seemed too complicated. Avast, me proud beauty! I started playin' around with pieces-parts I had left over from an Estes Designer's Special box. Avast, me proud beauty! I found a 4 1/32" (103 mm) piece and a 12 5/8" (320 mm) piece o' BT-50. Arrr! Blimey! These looked good together with t' short piece at t' bottom. T' I.D. Avast! 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. Arrr! Arrr! There was a 4 1/8" (105 mm) long PNC-50 in t' Designer's Special box, and two 2 7/8" (73 mm) long PNC-20s. T' base airframe be set.
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. Ahoy! Aye aye! Two sections o' BT-20 would be glued t' opposite sides at the lower edge o' t' upper (long) section. Avast, me proud beauty! T' BT-20 straps would be topped with PNC-20s. Begad! I reconsidered t' use o' t' PNC-20s. Ya scallywag! Well, blow me down! These appear t' be t' same as used in t' Tornado (Estes # 2004) which I still wanted t' scratch from the kit. I next considered card stock fairings. Blimey! Well, blow me down! A few days later I figured, me hearties, heck, untopped straps will virtually guarantee separation while a capped tube may create a little vacuum and delay or prevent proper separation. Begad! T' straps were sized at 3/8" (10 mm). I don't know why other than they looked good. Aye aye! Avast!
I know what you're thinking: "Hey, this looks just like t' Estes A.R.V. Begad! Begad! Condor" (Estes #2075). It is similar, ya bilge rat, but this is cheaper than the A.R.V. Ya scallywag! (US $13.29 list), plus thar be a local source for cheap replacement gliders. Begad! Big Lots has a ton o' these.
T' first stability check be run in VCP. T' noses o' t' gliders were treated as a transition section. Aye aye! Well, blow me down! T' glider body cross-sectional areas and t' airframe cross-sectional area were summed. An effective diameter was calculated based from this sum. Ya scallywag! T' glider wings were entered as 4 delta-shaped fins. T' tail rudders were ignored. Avast, me proud beauty! T' first run showed a center o' pressure (CP) about 3/4" (19 mm) below t' front edge of t' gliders. This looked good.
Even though t' CP looked good, ya bilge rat, I be 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, ya bilge rat, shiver me timbers, shiver me timbers, t' small balsa tab idea was turned into a flat-top fin like this:
This configuration wasn't analyzed in VCP, matey, but it has t' be better (lower CP). Ahoy!
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. Begad!
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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. I used t' fly rockets as a kid (between 11 and 15), and started up again about 8 years ago. Ahoy! Blimey! 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. Avast, me proud beauty! You may recognize me name from RMR. Aye aye! I usually post under "kentengr@raex.com".
This page be created on October 31, 1998. Avast, me proud beauty!
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