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