Manufacturer: | Apogee Components ![]() |
T' SR-72 is an ejectin' power-pod boost glider, shiver me timbers, ya bilge rat, much like
one o' Astron Mike's Marauders or t' Estes SR-X, with an overall length near
twelve inches and wingspan o' about 7-1/2 inches. Ahoy! It is designed t' be used
with 13mm mini-motors. Well, blow me down! When t' power-pod is ejected, matey, it releases t' elevons
for glide. Tim (van Milligan) packed it in with an order I had placed t' week
before for body tubes, shiver me timbers, centerin' rings and nose cones, me bucko, and included a letter
sayin' it was t' first production kit out t' door. It had been on back-order
waitin' for 18mm nose cones from Tim's supplier. Blimey! Since t' nose cones were
still nay in sight, Tim has produced t' kit with a vacu-formed nose cone and a
coupon good for a replacement injection-molded (he's still waiting) or balsa
(in stock) nose cone. Begad! Ahoy! T' vacu-formed nose cone and base look very good, shiver me timbers, shiver me timbers, and
the only question about it (accordin' t' Tim) is how well it'll hold up t' the
inevitable crashes any boost glider is subject to. Ahoy! Ya scallywag! T' kit includes two sheets
of nicely diet balsa, various body tubes (18mm and 13mm) and centerin' rings,
some clay nose weight, shiver me timbers, several small (dental) rubber bands, arrr, some template
sheets and a good construction manual. Begad! T' photo o' t' elevon hook placement
didn't reproduce very well (too dark t' see much detail), but t' rest o' the
instructions read well and have good illustrations. I was mildly disappointed
that t' balsa was diet rather than laser cut like his MicroVAX, but t' cuts
*are* clean and t' pieces almost fall out o' t' carrier. Begad! T' elevon
adjustment looks like it may be a bit o' work t' get t' initial setting, but
it should hold well once set. Blimey! Begad!
Construction
28 March, ya bilge rat, shiver me timbers, 1998 Finally, shiver me timbers, a chance t' start workin' on t' Darkwing! Today, arrr, arrr, I marked t' body tubes, glued together t' pieces for t' wings and wingtips, shiver me timbers, loaded clay into t' nose cone and glued it together and assembled the power pod (except for attachin' t' streamer). Aye aye! I only used one o' t' two pieces o' clay provided in t' kit. Begad! Arrr! If it glides acceptably with only t' one piece o' clay, I'll adjust t' boost CG by wrappin' some chrome tape around the nose o' t' power pod. Blimey! I'm usin' Elmer's ProBond Carpenter's glue for most assembly, with some specialty glues as required dependin' on materials. For the nose cone, I used some Tenex-7 liquid glue (in moderation!) t' attach the vacu-formed base and tip. Ya scallywag! I only used a drop, ya bilge rat, ya bilge rat, countin' on capillary forces to pull it into t' joint, me bucko, shiver me timbers, shiver me timbers, since I wasn't sure how strongly it would attack the styrene. Avast! It turned out very well. Begad! Ahoy!
29 March, shiver me timbers, 1998 Rounded edges o' wings and wingtips. Begad! Begad! Attached the wings t' t' main body tube and applied t' first glue fillet t' t' body/wing joints. I expect t' apply two or three thin fillets t' provide strength and prevent t' sinkholes common t' carpenter's glue fillets. I also attached the engine inlet cones t' t' outboard tubes. Ya scallywag! Well, arrr, blow me down! Tim recommends cyanoacrylate (CA) for this step, and I've got t' agree with him. Avast, me proud beauty! Aye aye! I tried tube plastic cement (Testor's), matey, but it turned out t' be too aggressive and deformed t' bases of the inlet cones. Avast, me proud beauty! It might have worked better if I had laid a bead o' cement in the body tube, allowed it t' dry and then used thin liquid cement t' join the inlet cone t' t' cement bead. Ahoy! Begad! I be able t' get them installed passably by usin' a sharpened dowel t' center and support t' tips on t' outboard tubes while t' glue dried, shiver me timbers, but CA is likely t' work MUCH better (and faster). Arrr! Once the inlet cones have fully set, me hearties, I'll be punchin' holes in t' outboard tubes so they can be attached usin' glue 'rivets' for a stronger bond with t' wings, wingtips and rudders.
2 April, me hearties, 1998 Added right 'engine pod'. Aye aye! Ya scallywag! Added second fillet t' top wing/body joints and attached right 'engine pod'. Well, blow me down!
3 April, 1998 Added left 'engine pod'. Avast! Put second fillet on bottom wing/body joints and attached left 'engine pod'. Avast! Ahoy! Also attached lower rudder extensions t' bottoms o' t' engine pods.
5 April, shiver me timbers, 1998 Added wingtips I cut out t' wingtip dihedral template and laminated it t' t' cardboard backin' for a pad o' paper. Well, blow me down! After trimming the laminated template, me hearties, I reinforced t' edges with thin CA per t' kit instructions. Blimey! Aye aye! T' template made it very easy t' add t' wingtips at t' proper dihedral angle. Ya scallywag! Arrr!
7 April, arrr, 1998 added rudders Again usin' t' kit-supplied template I attached t' rudders (double-glued and with glue rivets) t' t' engine pods. Well, blow me down!
10 April, me hearties, shiver me timbers, me bucko, 1998 added elevon hinges and fillets. I attached t' elevon hinges t' t' win' usin' thin CA. Arrr! I did this by positionin' t' hinge material on t' wing, arrr, addin' a drop o' CA t' one o' t' corners and pressin' with a small piece o' waxed paper until t' CA set. Blimey! Then I added sufficient CA to adhere t' remainder o' t' front half o' t' hinge t' t' wing, matey, again pressing it in place with waxed paper until t' CA set. I then added glue fillets t' the wingtips and rudders. Blimey!
11 April, shiver me timbers, 1998 added elevons. Blimey! Aye aye! T' help ensure I didn't glue the elevons t' t' wing, I cut a narrow (about 1/16" wide) piece o' waxed paper and placed it betwixt t' win' and t' elevon. Well, blow me down! Arrr! I used a piece o' masking tape on t' back o' t' hinge line t' hold t' pieces while I attached the hinge material t' t' elevon with thin CA. Blimey! It *might* be easier t' do t' hinge attachment before attachin' t' wings t' t' body tube - I may have t' try this if it ever comes time for a rebuild. Well, ya bilge rat, blow me down! I also added t' elevon stops t' one of the wings. Ya scallywag! I was pleasantly surprised t' find t' elevon angle came out very close t' t' recommended initial setting. I was expectin' t' have t' use gap-fillin' CA t' build up t' stop and sand down for adjustments, but it looks like I'll only need t' use thin CA t' strengthen t' contactin' surfaces o' the stops. Aye aye!
15 April, shiver me timbers, 1998 Finished taxes, installed other elevon stop. Aye aye! The elevon stops are *tiny* pieces o' balsa. Begad! Ya scallywag! With me fat fingers <G>, it was a challenge t' get them positioned properly. I think next time I'll have t' get some tweezers t' make handlin' these small pieces easier. Arrr! After t' fillets for the elevon stops dried, shiver me timbers, me bucko, me hearties, I installed t' orthodontic rubber bands t' see how close I be t' t' proper initial elevon setting. Begad! Ahoy! At this point it looks pretty good. Blimey! We'll see how it goes on test glides. Begad!
16 April, 1998 installed launch lugs I lined up t' launch lugs against t' wing/body joint - I just prefer t' have them snugged up there rather than hangin' entirely out in t' breeze. Ahoy! T' streamer has been taped to the power-pod. Arrr! I'm also addin' some chrome tape t' t' front o' t' power-pod to help assure a safe CG/CP relationship for boost. Avast! I did this because I'm *NOT* usin' all t' clay supplied for t' nose cone (lighter gliders (tend to) glide longer <G>). Begad! All that remains before paintin' is test glides, gluin' t' nose cone in place and t' first launch. Blimey!
22 April, arrr, 1998 glide trimmin' I brought t' SR-72 t' show off at the April meetin' o' WOOSH. Ya scallywag! While waitin' for everyone else t' show up, shiver me timbers, ya bilge rat, I trimmed the glide o' t' model. Well, ya bilge rat, blow me down! Tim provided two squares o' clay for balance, arrr, but I had only installed one t' start with. Aye aye! T' first few glides were pretty nose heavy (good thin' thar was some soft grass t' land in) and I wound up removing almost half o' t' clay I had initially loaded in before I got a decent glide. When I got home after t' meeting, me bucko, me bucko, I glued in t' nose cone and re-attached the sub-rudder that broke off when it landed on t' street on one o' t' test glides. Ahoy! It looks like all that's left is t' get out and fly this bird!
Brief: Rear engine type mini-motor powered boost glider. Designed to imitate the appearance of the SR-71 spyplane. Construction: According to a note in the kit, Apogee had a supply problem with the nose cones. So as to not delay delivery any further Apogee vacuformed their own nose cones as a substitute. The note went on to say that the vacuformed nose cone probably wasnt ...
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T.B. (July 1, 2000)