VVS, I for one can fully understand all your time invested in your D I Y foil project, looks fantastic! Please understand I am not being critical with my next statement, ONLY ment to suggest another way? By having the strut mounted on the fuse so far behind the front wing your are asking the section between to support all your weight when flying. First hand experience has seen 3 broken there. Even the new sword will have the strut leading edge almost directly above the front wing trailing edge as does spotz and ketos, also see scubas build above.
ketos strut to fuselage.jpg (204.07 KiB) Viewed 1614 times
Not only does this reduce the huge LEVER force on the fuse it also reduces the lever on the board as you are more centered over the strut. Just something to consider from a mechanial load bearing and stress point of view. This just seems to make more structral sense for board and fuse. R H May I also suggest the front wing off set 4 hole mounting pattern as alpine foil uses, this greatly increases the connection strength and stops the inline hole pattern axis roll stress, also simply mechanicaly stronger.
Thanks for the feedback. Yes, I thought about this problem. The first model of the fuselage was not strong enough at this point. I did a re-design. Now detail is very tough and durable .. As far strong, know after the test. Fixing the front wing with four bolts, it is a great option. I use three bolts , if that is not enough, then I will use four. Thank You for Your interest in my project. )
When all the lift is created by the frontwing and the rearwing is there mostly for traction/stability why are most of the rearwings curved down or up in the tips? Its logical in the frontwing to reduce wing tip wortices, but for the traction rear wing the preasure should be 50/50% up/down so a straigt foil should create less drag.
Guttorm wrote:When all the lift is created by the frontwing and the rearwing is there mostly for traction/stability why are most of the rearwings curved down or up in the tips? Its logical in the frontwing to reduce wing tip wortices, but for the traction rear wing the preasure should be 50/50% up/down so a straigt foil should create less drag.
my guess is that you are correct in assuming the rear wing is primarily used for pitch and heave stability.
however the tail section is also a good place to provide yaw stability if desired. if no vertical stabilizer is used in the tail then dihedral in the rear wing or upward angled wingtips could provide that function as well. Reducing tip vorticity in either wing is certainly possible, but the lift/drag benefits are only a few (<5) percent in applications that are actually designed for their use. Otherwise i suspect your "mileage may vary"