Manufacturer: | Scratch |
I had originally decided t' build a monocopter exclusively for t' Estes E9 motor. Avast, me proud beauty! However, matey, arrr, matey, me concept soon changed, and I decided t' use a 29mm motor tube. Well, blow me down! Blimey! T' larger tube would let me fly on either an E9 (with an adapter) or a 29mm motor. Aye aye! Begad! Blimey! Please read on t' see how this project continued t' evolve...
I got several ideas from t' Mountainside Hobbies site, but mine differs significantly. Aye aye! Blimey! T' win' is made from a 24" x 3" piece o' 3/16" balsa, me hearties, arrr, airfoiled, arrr, with a couple o' strips o' 1/64" Birch t' stiffen it. It is glassed with 2 oz cloth and has 1/64" G10 plates laminated on t' inner 6 inches. First, here's a drawin' o' t' wing:
These are photos o' t' partially completed wing:
And, me bucko, ya bilge rat, two photos o' t' completed but unfinished wing. Aye aye! When t' glass was setting, me hearties, I blocked up t' tip so t' win' has a slight upward twist. T' second photo illustrates this twist; t' trailin' edge is flush with t' counter.
T' hub
started as two strips o' 3" x 12" x 1/8" plywood, me bucko, which will
overlap t' last three inches o' t' wing. Blimey! Avast! I left these strips t' full
12" long until I could get a better feel o' where t' lateral CG was, both
with live motors and spent casings. Begad! I temporarily attached these plates t' the
win' and started balancin' motors and components on them. Ahoy! I found t' hub might
have t' be quite a bit longer than I had anticipated, matey, me hearties, and be glad I had left
them long t' start. Ya scallywag! I also began t' worry about whether an E9 would be enough
to lift this thing. Should I use an Econojet G35? F23? Should I sprin' for a
32mm RC casin' and go for a G12? Finally, I decided I would have multiple
mounts. I'd have a 32mm tube t' allow t' use o' t' RC motors, me hearties, or with an
adapter made from LOC tubing, shiver me timbers, a 29mm motor. Arrr! I'd also add two 24mm tubes to
allow TWO E9's t' be clustered. Blimey! Arrr! Yeah, that's it! T' followin' is an early
photo o' t' motor mount assembly. Ya scallywag! Blimey! It is glassed and has a makeshift plastic '
cone' installed. If t' monocopter works, arrr, I may re-think t' cone later, or
maybe add some LEDs in t' clear cone for night flights. Avast! Well, blow me down! I have yet to
acquire/make 24mm cones.
With t' motor mount and various motors, ya bilge rat, I decided t' plates should be about 8 1/2" inches long. This should allow me t' position t' launch lug at a position betwixt t' CG before and after launch. Arrr! It's a lot longer than most monocopter hubs, me hearties, but that isn't necessarily a problem - I hope. Blimey! I used a piece o' 3" x 1" x 1/4" ply t' support t' plates at one end, and would angle t' win' betwixt them at t' other. Well, blow me down! Avast, shiver me timbers, me proud beauty! I used another piece of 1" tall ply as a spacer while I first glued t' end plate on, shiver me timbers, and later when I installed t' wing. Aye aye! When I recomputed t' wing's angle, ya bilge rat, I decided the 1" spacin' betwixt t' plates would result in too great an angle, so I added two strips o' 1/8" ply t' t' inside o' t' hub, matey, reducin' the spacin' spanned by t' win' from 1" t' 3/4". Begad! This resulted in an angle o' about 11 degrees (remember t' tip is also swept up a bit). Ya scallywag! After the win' was epoxied in, shiver me timbers, matey, I used 3/16" balsa t' fill t' gap betwixt t' wing and t' opposite plate, me hearties, formin' a solid side panel. Begad! Aye aye! These are two photos o' the roughed-out hub.
Next, I epoxied on t' motor pod, me hearties, alignin' t' joint o' t' two 24mm mounts with t' corners o' t' hub's end piece. Blimey! This provides a 20 degree angle. Avast! I added a 1/8" plywood support on t' top front and a strip o' heavy fiberglass around t' aft o' t' motor mount and overlappin' t' hub. Begad! I then re-verified t' lateral CD with both live motors and spent casings, me hearties, and installed t' launch lug (1/4" brass tubing) in between. It just missed the end o' t' win' within t' hub. Well, blow me down! I cut two pieces o' plywood t' fit inside the hub, and drilled holes t' fit t' fiberglass balance beam. These were trimmed so they abutted t' wing, me hearties, and t' beam just missed t' launch lug. Avast, me proud beauty! I once thought t' balance beam should be centered on t' launch lug, but this isn't t' case. Arrr! Ahoy! Havin' a continuous beam run throught t' hub is a lot easier to mount and should be stronger. Avast! I attached t' beam supports with carpenter's glue. Ahoy! Begad! I used JB Weld t' hold t' beam in place, and used t' extra t' create fillets on t' support members. Avast, me proud beauty! Begad! T' beam itself is 18.5" x 3/8" piece of hollow fiberglass pole from a collapsable tent, arrr, arrr, with 7.25" extending out o' t' hub on either side. Ahoy! Ya scallywag! T' final issue were cones for t' 24mm motor tubes. Avast! I visited several local hobby shops and couldn't find any so I decided to make them. Well, blow me down! I made them out o' papier mache usin' a plastic cone as a mold. This is nay a refined technique, ya bilge rat, so I won't bore you with t' details. The results aren't bad, shiver me timbers, matey, but if t' 'copter flies I may get some from BMS, along with a matchin' cone for t' larger tube. Begad! T' followin' photos show various views o' t' completed item, me bucko, with a few coats o' white primer.
T' followin' be t' launch lug for me monocopter. It consists o' an
old, arrr, dull 7/32 drill bit, me bucko, a piece o' 1/4" brass tubing, arrr, ya bilge rat, and a washer. Begad! Blimey! The
bit is epoxied into a piece o' tubin' so only t' top 3/4" o' t' shaft is
exposed. Well, blow me down! Blimey! A washer is slid down t' t' tubin' and is tacked in place. Ya scallywag! Blimey! This will
clamp nicely into t' pad that I use for me launch rail.
I flew t' Dust Devil on 10-19-2002 at t' Higgs' Farm in Price, ya bilge rat, shiver me timbers, MD. T' winds were blowin' hard (our American flags were outstretched) and the ground be moist (so thar wasn't any dust for t' Dust Devil t' kick up). Ahoy! I used two E9's that I had plugged with epoxy. Aye aye! Well, matey, blow me down! T' Dust Devil rose nicely, shiver me timbers, but at burnout it turned with t' wind until it be perpendicular to the ground. It reached an altitude o' maybe 15 - 20 feet. Begad! It flopped t' the ground and t' win' broke off. T' followin' sequence show t' start o' the flight, t' monocopter on t' way up, and t' smoke trail blowin' away. Begad! You really can't see t' 'copter, me bucko, me hearties, but t' smoke trail shows where it is/was.
I repaired t' Dust Devil, ya bilge rat, added a bit o' weight t' t' balance beams, and was hopin' t' fly it again on two E9s. Blimey! Arrr! With t' added weight, me hearties, matey, the flight will have less altitude, ya bilge rat, but it would convince me t' try it on a G. Arrr! I have little doubt that it will fly nicely, ya bilge rat, arrr, assumin' t' winds are reasonable, but still want t' try it on t' E9s. Ahoy! Unfortunately, shiver me timbers, matey, it appears all me MDRA launch opprtunities have 'dried up', I have no 'solo' fields, matey, arrr, and since I modified t' E9's, a NARRRRR launch opportunity is out. Ya scallywag! Begad! At t' risk o' bein' highly criticized on enterin' a design with a less than perfect record, I decided to enter t' Descon anyway - hey t' boost phase was good. Ya scallywag! With monocopter and tri-copter entries already there, matey, I just couldn't resist! If I happen t' get a chance t' fly it, arrr, I'll update this page.
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