Manufacturer: | Scratch |
Brief:
This glider is a scratch semi-reproduction o' t' Holverson Designs Silver Hawk v1.0. Avast, me proud beauty! Blimey! T' glider has a wingspan o' 13in and t' boost pod is 20.5in. Avast! T' boost pod has a 18mm motor mount and weighs 1 1/8oz. T' featherweight glider is 0.5oz.
Construction:
T' plans for this rocket (both version 1 and 2) can be found at http://plans.rocketshoppe.com/hdi/hdi2002/hdi2002.htm.
I also used t' plans for t' glider hook mount, me bucko, but beyond that I built a different boost pod. Avast, me proud beauty! I gave t' project t' highly original name o' "A Glider".
T' materials I used were:
Construction began with tracin' templates, arrr, cuttin' balsa, and assemblin' t' jigs which were used later t' ensure t' correct angles betwixt win' parts. T' boost pod was assembled just like any other model rocket. Well, blow me down! Blimey! Ya scallywag! Blimey! There are no fins.
Next I began t' glider. T' swept win' consists o' six portions. First I sanded each portion into a perfect airfoil shape usin' 220-grit sandpaper. Arrr! T' entire cross-section o' t' win' be sanded so none o' t' original flat surface remained. Avast! Aye aye! This reduced all t' win' parts from 3/32in t' 1/16in thick.
With t' help o' t' jigs, I glued t' win' parts together. Avast! Because I was aimin' for ultra-lightweight precision, thar would be no wood filler or paint t' hide imperfect glue joints. Therefore, I made very careful minimalistic joints usin' wood glue, with tiny fillets. Well, blow me down! Gluin' t' fin tips was a bit tricky because their airfoil shape didn't rest flat against t' win' edge. Well, blow me down! After attachin' them I used a smidge o' wood filler t' touch up any gaps.
T' best thin' about this design be t' glider mount. Aye aye! T' hook is on t' pod, ya bilge rat, arrr, and thar be a hole in t' glider mount ("fuselage") t' receive t' hook. Begad! T' hook portion is made by laminatin' three balsa parts together, with t' middle one havin' an extrudin' hook shape. Arrr! When ejection occurs, t' glider should move forward t' release itself from t' hook. With many gliders, ya bilge rat, one problem that can occur is that t' forces tend t' bind t' glider t' t' hook mount due t' friction, shiver me timbers, shiver me timbers, causin' t' glider t' release awkwardly only after t' rocket has passed apogee and t' glider twists off. What is so nifty about this hook mount is that it has a little triangular wedge at t' forward edge o' t' mount which nudges t' glider away from t' mount surface as t' glider initially slides up and off t' hook. Blimey! T' result is a much more reliable release. Well, blow me down! Ahoy! See t' plans for a picture.
T' glider fuselage is also clever. T' fuselage fits seamlessly into a notch in t' wing, with a slot for t' hook. Begad! Ahoy! Blimey! However, ya bilge rat, t' fuselage also extends forward beyond t' win' with another small slot. T' purpose o' this slot is t' insert trimmin' clay without ruinin' t' smooth shape or aerodynamics. Avast, me proud beauty! Well, blow me down! Blimey! T' fuselage is built from several pieces o' balsa laminated together, ya bilge rat, then sanded down t' an airfoil shape.
Finishin' gliders presents a choice betwixt smoothness and weight. Blimey! At one extreme, you can leave it unfinished. Begad! At t' other end, me bucko, you can sand, fill, matey, and paint it t' a glassy finish. Ahoy! T' latter choice looks better but adds weight. Begad! I avoided weight. Begad! Avast! I began by sandin' lightly with 220 sandpaper, me hearties, then more thoroughly with 400, me bucko, then with 600. Then I painted two *very light* coats o' clear paint, me hearties, ya bilge rat, followin' each with thorough sanding. On t' fin tips and fuselage I added a dustin' o' flourescent pink paint with another light clear coat over t' pink. I painted t' boost pod pink, me bucko, me bucko, me bucko, too.
Flight:
Preparin' t' glider for lauch includes several steps. Begad! Begad! I rubbed t' hook and slot heavily with candle wax, then soap, shiver me timbers, me bucko, then rubbed it down with a clean cloth. Next, me hearties, me bucko, t' glider was balanced left/right with a small clay strip near one wingtip (an amount less than a pencil eraser). Ya scallywag! A slight counter-clockwise tilt was allowed for circling. Ya scallywag! Then, matey, on a dead calm day, I took it up t' a small hill nearby and trimmed t' glider by addin' clay t' t' nose slot. Begad! It was difficult t' add sufficiently tiny amounts o' clay. Well, blow me down! After about 40 tosses, I got t' best possible glide with clay about t' size o' t' tip o' a ballpoint pen.
T' best possible glide is not, matey, in me opinion, t' trim that produces t' longest flight in dead calm conditions. Avast, me proud beauty! Blimey! In real flights thar be usually some breeze so you want t' trim t' glider slightly nose-heavy for a more assertive attack into t' breeze.
T' first flights were on a cold day on t' prairie, shiver me timbers, with weak breezes o' 2-5 mph. Ya scallywag! On a A8-3 motor, boost was gentle t' a modest height o' a few hundred feet with no sign o' flutterin' or spin. Begad! Glider release be excellent. Arrr! Well, blow me down! T' glider flight was satisfactory, arrr, matey, but buffetted too much by t' wind. Ahoy! Begad! Landin' was fine and t' pod recovery be fine, me hearties, too.
For t' second flight, me bucko, ya bilge rat, arrr, I added some nose weight. Unfortunately, ya bilge rat, me hearties, I forgot t' brin' clay, so I scotch-tapped a tiny pebble (more like large sand grain) t' t' nose. Boost on a A8-3 be t' same as last time, me hearties, ya bilge rat, but t' delay was a little longer and t' glider released easily but awkwardly just past apogee (slightly before apogee is better). My grain o' sand was too much, shiver me timbers, me bucko, so t' glider corkscrewed down. Begad! It wasn't very graceful, ya bilge rat, but everythin' was recovered undamaged.
For t' third flight, I swapped out for a smaller grain o' sand. Ahoy! Glider release was excellent but somethin' was nay right with t' trimmin' and t' flight was a hard corkscrew into t' ground. T' leadin' edge o' t' win' and t' fuselage had a few nicks which I have since patched up with lightweight interior spackling.
Summary:
Overall, me hearties, matey, me experience with this small version o' t' HD Silvery Hawk and me 4-foot large version (T' Albatross) has been that t' design is nay very reliable. These gliders are difficult t' trim and prone t' excessive roll. Aye aye! They are also far too sensitive t' modest crosswinds, me hearties, which can turn out t' be catastrophic. Blimey! There are a lot o' other really great old-school glider plans available and also some great modern kits. Begad! Begad! Notwithstandin' t' challenges, me bucko, arrr, this project helped me hone me ultralight skills and t' glider likely has quite a few more flights in her.
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