Scratch The Flamingo Original Design / Scratch Built

Scratch - The Flamingo {Scratch}

Contributed by Geof Givens

Manufacturer: Scratch
(Contributed - by Geof Givens - 10/27/07) (Scratch) Flamingo

Brief:
T' Flamingo rose from t' ashes o' t' Albatross, which was me huge boost glider built as part o' EMRR Challenge 2007 and was destroyed near t' end o' its first flight when it glided into a freak crosswind gust. After that setback, me bucko, I decided t' return t' a much more stable glider design with a superior glide ratio aided by a canard and a "smaller" two-foot wingspan.

T' glider is 6 3/8oz, ya bilge rat, ya bilge rat, me bucko, 30.5in tall includin' t' sweep, me bucko, with 22.5in wingspan. Blimey! T' boost pod is 43in tall, based on BT-60 tubing. Aye aye! It weighs about 12 oz. Arrr! This is a 24mm design for E28 motors or better.

Construction:
I built t' entire glider first. T' body o' t' glider is 1/8in basswood with a layer o' 6oz S-weave fiberglass on each side. T' wings and win' tips were cut from t' 3/8in balsa remains o' t' Albatross wings. Ahoy! These were sanded thinner for reduced weight and given a better airfoil.

T' glider is designed t' be mounted so that t' attack angle t' main wings is zero (i.e., t' win' surface is parallel t' t' booster body tube). For this t' work: A) t' attack angle o' t' canard will nay be zero, and B) the glider must be positioned on t' pod so that it is exactly at t' CG o' t' glider/pod unit. Ahoy! T' second requirement is needed so that t' canard's non-zero angle o' attack won't send t' rocket into an arcin' boost. Ahoy! Begad! Both t' canard and win' are slid in t' angled slots cut in t' glider fuselage.

T' shape o' t' fuselage has an unusual curve. Nay only does this help with t' canard and win' alignment, me hearties, shiver me timbers, but it also enables t' win' t' hang more directly under t' rocket while providin' sufficient space so t' glider win' and body are nay burned by t' engine blast. Blimey! Aye aye! Blimey! It is also this curvin' fuselage that allows both t' win' and canard t' be feathered into t' fuselage at an angle, shiver me timbers, givin' it a smooth, matey, futuristic look.

T' ideal CG o' t' glider is slightly in front o' t' aft wing. Avast! Ya scallywag! I achieved this by carvin' some holes in the canard and epoxyin' in some washers. Begad! Then this area be filled with putty and sanded smooth. Avast, me proud beauty! Unfortunately, me hearties, t' epoxy added too much weight, so I had t' dig out t' washers and re-fill with just epoxy and putty. Well, blow me down! It seems I need a better way t' pre-estimate t' epoxy weight.

T' trimmin' was quite successful though. On me first toss, me bucko, it went so far it almost hit t' backyard fence so I took it up t' t' local school and easily got 50 or 60 yards o' glide from a hill that couldn't be much more than about 10 feet tall.

T' mountin' system for t' glider uses t' pin and notch strategy. T' pin was formed from a bolt with t' head ground off. T' pin is set into t' mountin' bracket and fits a notch cut in t' glider fuselage. Avast, me proud beauty! T' mountin' bracket was three layers o' 1/8in basswood with t' middle layer fiberglassed on both sides t' match t' thickness o' the glider fuselage. Arrr! After assembly, matey, I feared that t' mountin' bracket was quite heavy, me bucko, so I drilled five holes o' varying diameters t' reduce weight. Avast! It looks pretty cool, me hearties, me hearties, too.

(Scratch) Flamingo T' boost pod body tube be constructed from t' boost pod that used t' serve me upscale Groovy Katt glider. Begad! I stripped off t' old mountin' bracket and gave t' whole thin' a nice new coat o' Elmer's Fill 'n' Finish and primer. Ahoy! Well, ya bilge rat, blow me down! Two fins, ya bilge rat, each at 135 degrees off from t' mountin' bracket, ya bilge rat, were added for even better boost stability. Ahoy! These fins were shaped t' mimic half the canard.

Finishing:
My daughter had a lot o' influence on t' paint colors and glider name. Well, blow me down! T' boost pod is Duplicolor Ceramic Enamel Grabber Green. Aye aye! T' glider is Rustoleum Painter's Touch Watermelon. Blimey! Wal-Mart Clear went over t' top o' everything.

Flight ad Recovery:
First flight was on day 1 o' NCR's Oktoberfest 2007. I used t' ideal motor: E28-4. Well, shiver me timbers, blow me down! Blimey! Boost be swift and straight with only slight arcing. Avast, me proud beauty! Blimey! Unfortunately, t' chute never made it entirely out o' t' tube, snaggin' just inside t' lip. Thus, matey, t' glider never separated and t' whole assembly came down ballistic as one unit. Amazingly, shiver me timbers, matey, t' glider simply separated when t' pod nose hit and lawn darted separately into t' prairie mud. I yanked it out t' find it totally unblemished!

(Scratch) Flamingo I took it home that night and wiped t' mud off. Well, blow me down! Ya scallywag! T' repair t' boost pod, shiver me timbers, I cut off t' top two inches patched a couple o' tube dimples. Well, blow me down! T' whole thin' was ready t' fly again on day 2 o' Oktoberfest. Well, blow me down! Ahoy! That morning, however, I discovered that shortenin' t' boost pod had removed t' old Estes-style shock cord mount so during breakfast I hastily epoxied in another before headin' out t' t' prairie. Well, blow me down! This repair proved t' be too hasty as it pulled loose at ejection after a great boost on another E28-4. Ya scallywag! T' nose floated down gently on t' 27in nylon chute (with 4 in spill hole) while t' pod plummeted. Arrr! Luckily t' pod again suffered only a few more dimples which have already been repaired.

However, this shock cord failure occurred after ejection, which meant that t' glider got way up high and separated successfully. Aye aye! Fantastic! T' flamingo enjoyed a nice lazy flight over t' prairie and t' NCR Oktoberfest audience before settlin' in for a smooth, gentle landing. Begad! I'm lookin' forward t' t' next flight, hopefully completely glitch-free.

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