Flying from either snow or water is one of the most realistic and enjoyable aspects of R/C aviation that you can be involved with. If you have ever been intriqued by this, read on.... There is some good information ahead!
Firstly, I would like to thank RCM magazine for allowing me to use this excellent article on float building by Chuck Cunningham. This is the article I have used as a guidline for float building since in was printed in April 1993. Chuck has written more on the subject over the years but this is still my favorite article. I have many back issues of RCM magazine. If further information is needed please contact me and I will do the best I can to help.
Secondly, my thanks go out to George Nichols of Salmon Idaho. All the Ski pictures and ideas presented here were sent to me by George. The folks in his club appearantly know what they are doing when it comes to ski building and flying. While I have not built any of these skis myself, as of yet, it is obvious that it is a simple, lightweight, flyable method of building skis.
I have scanned Chuck Cunningham's float article so that it can be printed out and reviewed as you build. Click on the article to enlarge it first, then use your print button.
As you will see in pictures of my floats below, I have tried different mountings. By far my favorite is the trike gear mounting. What a great and easy way to mount floats. It also allows easy adjustment of wing to float incidence for best take off attitude.
I have tried covering my floats with balsa, 2 inch clear packing tape, and glass cloth and epoxy resin. All work fine but for the fastest, cheapest, lightest.... the 2 inch tape method works the best! It almost sounded to cheesy for me to try, but I love it! Tape them up, hit them with some steel wool and paint to match the plane.
Plan on a water rudder of some kind too as you are building. I hear from people that say it is not needed. Well the way I fly, in the wind I fly in, and what I expect from my plane, demands a water rudder when on the lake. It is more than worth the effort. Remove the water rudder and use these on snow too.
This next section is about floats that I have built and flown.
These floats work as well on snow as they do water.
On snow remove the water rudder, the aircraft turns great with only the air rudder.
This next section is from fellow r/c pilot
Many thanks for all great pictures and descriptions.
Heavy paper patterns, save them for future floats as your friends will want to borrow them.
Floats getting ready for an Ugly Stick .60. These are fiberglass and resin covered. Now in primer stage.
At nearly 4 feet long, these are my favorite set. Probably because they are used on my Kadet Senior.
At one time I had "pockets" in front on the step and installed 2 1/2 inch wheels, flew off of land and water. Cool stuff, and fun!
The nose gear set-up. Super simple. These floats can be put on in minutes.
Store bought water rudders and rear spreader bar. I use ny-rods to control the water rudders.
These pictures show a mounting system for my Midwest Aero Star .40. My first plane, and my first float plane. The water rudders are built from scraps of sheet brass, music wire,brass tubing, and steering arms. A bit of soldering and you are ready to go. The water rudder is driven from a music wire/ ball link connection to the air rudder, real simple.
A couple of pictures of the Areo Star on floats.
These pictures were captured from old video tape.
Homemade Skis and Floats to go!
Using scrap Formica from any cabinet maker shop, cut ski bottom to approximate length and shape. Using a belt sander if possible, sand to exact shape and then mark a center line on each ski upper surface with a felt tip pen.
Using approximately 3/8inch thick pine for .20 and .40 size craft, and 1/2 inch thick pine for .60 and up, cut a pair of ski ribs to the curvature you would like your ski built to. Save the scrap wood to make an axle block for gear attachment.
Make sure that the slick / shiney surface of the Formica is on the outside of the curvature then epoxy and clamp the rib to the ski base. Be sure to center to rib on the previously drawn center line, let the epoxy dry throughly before unclamping.
Epoxy the Gear block in place and use scrap Formica to reinforce the glue joint on each side. Block the ski up on its side and drill the appropriate size hole for the gear attachment on your airplane. The Formica makes an excellent wear surface for the gear attachment point.
1/16th music wire is coiled a wrap or two around the axle and then attached to the main gear above the ski. It is then cut to length and ran rearward, bent down, and through a hole in the ski rib. The length of wire fore and aft help determine the flex of the ski on the gear. Experiment a bit here for the best set up on your plane.
Once that the torsion wire is made and installed, a bit of bending the torsion spring will allow you adjust the ski for a level no load situation. Naturally, heavier wire could be used on .60 size and up aircraft to help maintain the proper spring action on the ski.
No wheel collar is needed on the torsion wire throught the rib. I suspect that a bit of a bend on the end of the wire may make some of you feel better with no weight penalty.
Dural gear is setup very similar as the wire type gear. Only difference is that a small hole is drilled in the gear and the torsion wire is bolted on using small bolts and lock nuts. On the wire gear the upper wire is simply wrapped around the landing gear leg.
Bill Peterson is showing the proper angle to set the skis to before flight. These torsion springs let the skis "float" over the snowy terrain.
Here is a tail wheel set up built for George's .20 size Cub. This should give you a good idea of how versitle this ski set up is.
Beautiful set of skis on George's Kadet senior. A slit was cut in the lower part of the front ski and a piece of Formica was glued in place for better turning. It made a big difference on the ground handling.
Here is a picture of a number of different size skis. As you can tell, nothing is set in stone. Use what you have available for materials, a bit on TLAR ( That Looks About Right ), and go for it!
This is the whole reason for building skis......... It is absolutely gorgeous out on a nice winter day. Don't wait for a hot, humid day to enjoy your r/c airplanes. These skis will open up a whole new adventure.
And a note from George.............
I hope you have as much fun building these as I do. You will find that the snow conditions will change the requirements for the skis. Light fluffy snow will require a larger ski. You can get by with smaller skis in both length and width on hardpack and frozen snow. I make my skis a bit oversize to handle both situations. Only a slight trim change is needed between the ski and wheels.
You will notice that I use a gradual slope / bend in the ski instead of an abruptly turned up tip on the ski. They stay on top of the snow just fine like this and seem to require little trim change in flight. Get a set of skis built and star working on that "All Weather patch".