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Posted by Michael V | Jun 16, 2017 @ 11:18 PM | 1,143 Views
some basics on RF and antennas:
1- There is "transparent" material, and then there is "mirror" material. RF and light are the same, so it's easier to make analogies. Carbon fiber is "mirror", so is any conductive material. Also acting as mirror any mesh (conductive) for which the holes are smaller than the 1/2 wave length (for 2.4 it's about 2.5") (hence the grid on microwave windows). So a chicken wire fence is a shield/mirror to 2.4 (think about this Fermin flyers).
Mirror material acts as a mirror behind but as a shield in front (roughly, there are technically interference patterns and diffraction, but never mind for now, that plays a role however if the mirror/shield and the antenna are in proximity to each other), so antenna with CF on one side either gets better reception (CF behind the antenna from Tx) or is shielded by the CF.
So in your case I'd be concerned by the CF, but mostly by the lead that seems to line up the whole front of the fuse except the top (I think it's lead from the picture). Same for any metal in the ballast tube and the ballast tube itself if it's metal, it may create a "shadow". Try to position them where they get the most clear line of sight of the transmitter in normal flying.
It's not black and white, we're always talking about degrees of attenuation. If you fly close, most likely it always works, but the reception will be weaker when the antenna is in the "shadow", so as you get more...Continue Reading
Posted by Michael V | May 20, 2014 @ 10:13 PM | 3,161 Views
Okay guys, after reading much stuff left and right on how to stiffen a wing with carbon rods, or slats, where, etc.. I realized that even if I had a general grasp of the principle, I didn't have more exact data. So I looked it up and calculated what I could.
So here it is, as is, with no guarantee whatsoever.

There is a big document explaining in details (I hope) and the two main tables that derived from the calculations.

There are many more factors involved (mostly geometry) and especially in composite material (skins, skin adhesion, etc..) but this is a fair starting point IMO.

Have fun and make planes! (and feel free to comment critic, add, etc..)
Posted by Michael V | Sep 18, 2013 @ 07:08 PM | 4,031 Views
Some time ago I started a new project, ambitious but that's how I like them.

I wanted to design a slope "jet". Before I tackled my favorite jets (F16, F14, F18E, some are already in progress, design stage) I stumbled upon the SU37 thread as a parkjet so it inspired me to design a SU 27 (no canards yet, that may become a later project, baby steps see)

So here I went and designed from scratch.

I used MPF (Model Plane Foam) as it is the best medium out there in my opinion.

The basic design objectives were:
1 - Light plane
2 - Enough lift so that it would fly correctly
3 - Simplified overall shape, yet good enough to look good and "scale"
4 - Smart enough aero design in the hope that it would perform some "post stall" maneuvers although I knew that was borderline impossible considering the format (light, lack of engines, has to be stable (CG forward of AC))
4- Test bed for some ideas in design (direct drive control surfaces)
and hopefully it would fly well and be fun to fly too.

So a list of design choices were made (to be tested):
- Foam, painted in acrylic and covered with laminating film
- Some LE reinforcement, 3/16 wood round
- Direct drive tailerons, no other surfaces for the time being
- Airbrake, for fun, and also as a access hatch for the electronic, more on that later
- Subsonic wings, based on KFm2 airfoil for gentle stall characteristics and ease of building. No flat plank here, this thing needs to soar.
- Lifting "engine...Continue Reading