I designed and built this winged dirt/iceboat about 10 years ago. I designed it under a box rule. About 7 of them were built in some form. In hindsight I wish I had made it a one design. I think it would of been more popular. The wings are interesting to design and build and fun to sail. They are also inexpensive because they are mostly made of plywood.&index=19&list=FLKqJHJ2yH8UtL89rICpofSA&t=0s
The flap is a NACA 0015
Here is a wing with a tapered flap
The main wing tee or wing/mast step and mainwing control wheel
The fuselage covered in 1/4" plywood
angle bracket to connect the axle or runner plank to the fuselage
2 Angled brackets to connect flap index to flap
The mainwing sprocket
The flap pivot hinges that go in the middle. The square stock goes into the trailing edge of the main wing and the round rod goes into the flap
The angled receiver bracket make 2 each. The tee slides into these brackets
Flap control handle with spring loaded trigger to index into flap index. It holds the flap in place at various angles
The flap index. The drawing doesn't show but the index should have notches cut into it every 5 degrees to allow the flap to beheld in place at the those angles. Notches approximately 1/8" x 1/2"
There are a few things about the design I would do if I were to make a one design. I like the wing profile with the tapered flap that is 16' tall or 192" tall. The axle could be around 12 ' wide and the wheel base for and aft about 14' long. I design the main wing to have a 20 % thick chord with the thick point at 40% back from the leading edge. The flap could be a NACA 0012. To locate the flaps pivot point on the trailing edge of the mainwing multiply the flap chord length by .095%. example 20.5625 x .095 = 1.95" . By locating the pivot point using that formula the flaps leeweard side lines up well with the mainwings leeward side when the flap is deflected at 20 degrees of angle. It also achieves a nice slot to.
Why slotted flaps work the best - aviation.stackexchange.com/questions/30960/how-does-the-slotted-flap-workhttps:
Hi John , Is the rear axle a single strip of wood or is it laminated, I seem to remember from a post a few years ago that it was laminated with a curve built in.
Its 3 pieces of .75" x 10" with a curve laminated into it. I think if it was just for landsailing it could be flat.
Great topic US772. One question I have (among many...) is why do many of the US yachts use a wheel/chain/gear for wing/mast rotation adjustment and the Europeans use a spanner/rope system? Have you found advantages/disadvantages to either?
When you tack a soft sail into the wind it luffs. When you tack a solid wing into the wind it ossilates. It is searching for a direction to go. when ossilation happens it usually reults in the complete distruction of the yacht. You can't stop the ossilation! The chain and sprocket has no slack. A rope used as in conventional sheeting does have slack. Slack in control system = SUICIDE! Unless the wing is counter balanced. See Richard Jenkins Craft
Example mast limiter snaps because of slack. Wing mast osdilates game over. Sequence of events - going 78 mph on spar alone 1 boat hikes
2 let out mast limiter cable to stop hike
3 slack line starts instant wing ossilation
I remember watching that oscillation crash a few years ago, not great for the builder/pilot but very spectacular. Thanks for your insight on this topic.