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Posted by trevorires | Nov 14, 2020 @ 08:41 AM | 7,505 Views
For lack of any skill or knowledge in this area, my original inention was to use Mark Drela's HT and AG series per the Allegro Lite.
After a club member mentioned the SD3021 aerofoil I looked into it a bit more.

Quick note that most of the F3res high performing lightweight 2M's seem to have all conformed to either a 7" or 8" wing cord and also Allegro-Lite has a 1.5 deg wing incidence.

I was thinking that the SD3021 might be somehow suited to a larger wing cord as it is mentioned in many older designs when wanting to upgrade flat bottomed wings.
I have opted for a slightly bigger wing cord of 9" (230mm) hence my interest in the SD3021, after the comment.

Here's the mind bend - when I plot the SD3021 at 1.5 deg it comes out as a sort of flat (see pdf), it is as if I would need to put the wing incidence up more ie: 3 deg..which is interesting as the Olympic II wing incidence is 2-1/2 deg (do not know the aerofoil on the Olympic II)
Posted by trevorires | Nov 13, 2020 @ 07:45 AM | 96,362 Views
The intention is to design a 2 meter RES glider that is strong enough to winch launch and also F3-RES (Woody fly-in) compliant. The idea came from having an i-beam type of platform for mounting different wings.

Wings:
Different wings could be tried with wing cords from 8" to 9-1/2" an optional sport flying 100" wingspan could also work with this fuselage.
The current pdf shows the Mark Drela polydyhedral wing, but at 230mm wing cord.
Sonoran Laser Art offers a "Yellow Jacket" wing kit.
I also like the Peter Goldsmith "Opal" wing shape.
I am investigaing the AG series and also SD3021 aerofoils.

Fuselage:
The curvy fuselage shape came from the Sailplanes International "Osprey 100"
The boom is the Goodwinds WCTAllegro032. The horizontal stabilizer is all flying with the option of an all flying fin OR conventional hinged rudder.
The fuselage is a little complex to build so I am considering creating some files for laser cutting.

Software:
I will use LibreCAD on my Linux machine to create the plans.
I am currently using Mark Drela's suggested basic calculation spreadsheets to see if this will fly and to get a theoretical CG etc...

Hopefully more detailed plans coming soon.

All the best,
Trevor