Sunbird (oz7221)
About this Plan
Sunbird. Radio control flying wing sailplane model.
Quote: "Can't decide on your next sailplane project? Why not give this quick building, great thermalling 2m flying wing a shot. SunBird by Mike Hollison.
Sunbird is a 2 meter flying wing, designed expressly for thermal soaring. It uses a reflex airfoil for pitch stability and clevons for precise lateral control. Anyone who has built at least one aileron controlled sailplane should have no difficulty with this model.
Construction. Wing:
1. Lay the 1/4 in sq spruce leading edge and the 1/8 x 1/4 spruce bottom main spar over the plan, and epoxy ribs W2 and W7 in place.
2. Cut the trailing edge from 1/4 x 1 in tapered stock balsa, slot for the wing ribs and epoxy to W2 and W7, propping the TE up with 1/4 in scrap to provide the necessary reflex angle.
3. Glue ribs W3 to W6 in position.
4. Next, cut the elevon support spar from 1/4 in balsa, slot for ribs W8 through W11, lay over the plan and epoxy to rib W7. Epoxy rib W11 in position.
5. Cement ribs W8 to W10 in place, and add the top wing spar.
6. Glue a piece of 1/4 in balsa between W2 and W3 and the two wing spars Add the 1/16 sheet balsa webbing between ribs W2 through W8 on each side of the spars, forming a box.
7. Cement sheet webbing between W8, W9, and W10 to the rear of the spars only. There is no webbing between ribs W10 and W11..."
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Supplementary file notes
Article pages, text and pics.
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-
(oz7221)
Sunbird
by Mike Hollison
from RCMplans (ref:1193)
June 1995
78in span
Glider R/C
clean :)
all formers complete :)
got article :) -
Submitted: 15/11/2015
Filesize: 677KB
Format: • PDFbitmap
Credit*: KraftyOne
Downloads: 5166
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User comments
Here are photos of my electric conversion of the RCM Sunbird. Should anyone be interested [pics 003-005].Dave Pentland - 10/10/2021
Ok I scaled up the plans by 104% so I could fly it at our big bird events. I made a 2 piece wing and sheeted the front for some extra strength. I suspect the wing ribs on the original plan were not accurate, and being a low resolution copy did not help.some of the issues I had were:
The leading edge of the ribs did not line up with the plan and needed to be trimmed to fit.
The turbulator spars did not line up. I’d cut them after the wing was assembled to get them straight.
W11 rib needs to be made from thin ply. No mater how carefully you a a balsa one will break.
I needed to scarf a 1/8” to the top of rib 3 to get it to the right height. Most other ribs needed a shim here and there to get thing to match.
Despite my carefully jigging I got to much reflex in my trailing edge. I make a template to sit on top of the ribs next time.
The torque rod slots weaken the rib and make them really easy to break. I’d do them after the wing was assembled next time.
I made the brass bearings for the torque rods to short. No matter how careful I was I got epoxy in them. I’d make them 5/16” long next time.
Hope this is of use to anyone else who builds this.
Dave Pentland - 15/10/2021
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- Sunbird (oz7221)
- Plan File Filesize: 677KB Filename: Sunbird-RCM-1193_oz7221.pdf
- Supplement Filesize: 1964KB Filename: Sunbird-RCM-1193_oz7221_article.pdf
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Notes
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Scaling
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