HugoW

Hi,

I bought a 15cc (.91) four stroke to fit to a Hog Bipe. But I enjoy scratch building too much to buy the kit, and I don't realy like the Hog's fuselage design. I like planes like the Super Stearman. So I'm looking for (preferably metric...) plans of a biplane, for this engine, a bit Super Stearman-like, with friendly flying characteristics. I don't need a 3D monster with prophanging abilities, but a slow-gliding Moth would be too gentle.

Anyway, many whishes, please advise.
Cheers,

Hugo

BMatthews

Years ago Model Builder magazine had a stand off scale design called the Barnstormer. It was a slightly thinned down copy of the Fleet biplane. I've got one that I bought at a swap meet years ago and it's a slow and gentle flyer while being delightfully "semi aerobatic" in that it'll do stuff but it wants you to be involved to make the stuff look better than just flopping around the sky. I really like it because of this. Scaled up a bit to suit your .90 and it would be a wonderful model.

Another option would be to talk to Concept models about getting their plan for the 54 inch version and blowing it up to around 65 to 70 inches.

http://www.mailbag.com/users/conceptmodels/index.html

HugoW

Thanks, Bruce. I've taken a look at them, and both have a certain appeal. Then again, I'm a bit strange in what I want, so I took many pictures and drew something up myself. Here it is, JPEG'ed form AutoCAD.



I really like open cockpits, but the closed one looks better in this design, I think. Basically, what I did was take the outlines of an Ultimate Bipe, rounding the edges and add a star-engine cowl. It should be 1.400mm (55" ) span, the lower wing has about 3 degrees V, it has NACA 0012 profile. The tail wing (English?) has no profile.

The fuselage would be 3mm ply with interlocking construction, the curves would be supported by 6x6mm balsa, covered with 1mm sheeting.
The wing would have 3mm balsa ribs, the front half sheeted in 2mm.

If I get positive feedback on this and it would seem a fly-able concept, I'll work out the detail drawings and post them as well. (BTW, should I open a new topic for that or re-use this one?)

Here's the [link=http://home.versatel.nl/witsenburg/Dubbeldekker.dwg]CAD file[/link], for those interested. It's only a concept, so far, please don't mind the drawing inperfections.

Cheers,

Hugo

sscherin

My Feedback: (1)

Looking at your drawing I was thinking a Pitts M12 would be great..

BBT has a 26% set of plans available for asking.
http://www.rcuniverse.com/forum/m_26...CBurton/tm.htm

You can request the PDF plan files here (yes it's free)
http://www.gundersonaerodesign.com/p...rtkits/burton/

I was thinking that if you printed them out at 80% it would be 140cm span. Just a bit smaller than a GP Super Skybolt.
As a bonus for you the plans are metric.

BMatthews

Well your sketches are certainly flyable. I find the wings to be a little small but not by much. They are fine as they are but if they were about 10 or 15% larger I think the desgns would look more harmonius.

However what you're showing here is more a 3D style model which I thought you didn't really want. But then again it is only 3D if you fly it that way and use lots of control travel.

And the fixed portion of the "tail wing" is reffered to as the stabilizer in english while the movable portion is the elevator.

Boomerang1

Actually, the fixed portion of the 'tail wing' is reffered to as the 'tailplane' in real english from England. We, in the colonies, have to follow suit or face the lash! (some of us actually enjoy the lash in moderation!)

But hey, you guys invented the 'airplane' (aeroplane in the empire) so call the bits what you want! [sm=lol.gif]

Good to see some scratch building going on. How about a Waco YMF 5 scratch built from the Pica kit plans?
Or a Fiat CR 42 - John

HugoW

Well, the drawing I made seems to become more attractive the longer I work on it. If you now click the link in the third post in this topic, I've uploaded a more detailed drawing, working out the wings and the tail section. (Bruce; I've indeed lengthened the wings a bit. Or, to be honest, I lengthened the wings and then scaled the lot back to 55" span. I'm in the middle of detailing the fuselage. I'm experimenting with a new material from the local DIY store. They call it 'hobby-ply' and it looks like 3mm multiplex from balsa layers. Weighs nothing, costs (relatively) nothing and seems strong and flexible in all directions. BTW, the purple rectangles in the drawing are A0 paper-size, for easy plotting.

I'm still feighting with the servos in the wings a bit; the NACA 0012 doesn't leave much space, but I think I need a powerfull servo to move the flaps on the top and lower wing together. Any suggestions?

Cheers,

Hugo

sscherin

My Feedback: (1)

You could go with a 4 servo setup for the ailerons and use slim wing servos.

Standard
http://www.servocity.com/html/hs-125mg_slim-wing.html

Digital
http://www.servocity.com/html/hs-512...ital_wing.html

You could put one pr aileron (2 in the upper wing and 2 in the lower) or 2 on each side on the lower wing (all 4 in the lower wing) and link the upper and lower ailerons together.

Idea #3 would be to use torque rods on the lower wing and mount 2 high torque servos in the center of the wing.. Then link the upper and lowers
I works for .40 size planes but for a big bipe it's questionable.. I'd want a hardwood block where the rod goes into the aileron.

HugoW

After some discussions on the Dutch RC model forum, I've redesigned the bipe. Here's a [link=http://home.versatel.nl/witsenburg/Dubbeldekker%201250.dwg]CAD dwg[/link] of both the assembly and some parts.

Please feel free to comment!

Cheers,

Hugo