Snowplane, radio gear

That's what I was wondering! Were you going to to tether your snowplane or make it R/C? Looks like it'd be a bunch of fun out on a frozen pond or lake !!!!!!!!!!!

I was thinking like this:

When it's that finished that it could actually run, try to run it free in a circle (if it will move at all?!), then make it radio controlled.

I don't see a rudder. Is steering just from the front ski? This could be interesting.

Phil

Cool! I'll be waiting to see how this turns out. When I first moved to Oregon here, I thought I'd get to do projects like this. Not enough snow, though...

Glad you're going to be able to run Coxes all year round.

The Congratulatory Mark

Thanks for your posts guys, Concerning the engine, I'd like to Dragonfly it, just to have some throttle control. Now, tests will have to determine whether variable rpm will be useful or not. It might be that when reducing rpm, the snowplane will just stop moving, I don't know. The steering is with the front ski indeed.



I hope to see some snow this winter. Last winter, it didn't snow at all over here.
Maybe a wet lawn in the morning will be OK as well.

Lieven

Looks nifty! Black Hawk Models makes a ski car called "Fast Eddy" that is powered by a .049 but is tether. I could never use one here in SoCal as winter temp is never close to freezing. Ah sunny and warm weather

Hi Lieven, That definitely looks like a Tatra! I'd like to see you throttle it. I made some engine mounts for that venturi throttle that I mess around with. The mounts were designed around a boat hull.. and have an offset bellcrank for fine-tuning the amount of linear-movement to the plunger-needle in/out of the venturi. You mentioned that a model like this might not move unless it was under full throttle. I think that if you give the pusher-engine some down-thrust.. it will accomplish two things; it will lift the rear-end for less friction to move forward.. and also make a single front steering-ski more effective. It's easy to make skis.. I made several pair out of aluminum "step-flashing", popsicle-sticks and a cross-tube for an axle/strut to attach. I used a straight-edge, and "creased" the thin aluminum lengthwise using an awl, to give the skis some directional stability. (like forming slight "V's" into the bottom). You can also spray some furniture wax or "armor-all" on the bottoms.

Brenda wrote:Looks nifty! Black Hawk Models makes a ski car called "Fast Eddy" that is powered by a .049 but is tether. I could never use one here in SoCal as winter temp is never close to freezing. Ah sunny and warm weather

Brenda, for places as where you live, there is this solution, a sowplane that can be modified. The skis can be replaced by wheels!!



The complete pdf file can be found on RCG:  

http://www.rcgroups.com/forums/showpost.php?p=18221066&postcount=3894

I've been thinking about skis already Roddie, but I'm not so inventive as you are. I found some inspiration on Kirt Blattenberger's website. It's an article about the same Call-Air snowplane as on RCG but this is a 1/2A version.

http://www.airplanesandrockets.com/cars/control-line-or-radio-control-call-air-snowcar-jan-1957-american-modeler.htm

The groove or some sort of knive on the bottom side of the skis is definitely an advantage for steering or track holding. i think the rear skis should even have some toe-in. what do you think?

Lieven

The description of the ski-construction (bottom of the article) seems over-complicated to me Lieven. Maybe the ammonia/steam-forming of the wood attracts you? After seeing the beautiful cowling you built for the "Caudron".. that wouldn't surprise me.

I don't know how wide/long the ski's need to be.. but large craft sticks (or tongue-depressors) are wooden.. and could be cut to the desired profile.. with a radius steamed into the tip. Are you going for "full-scale".. or "fun" scale? If you can find some thin steel stock.. (like what they "strap" shipping pallets/skids with.. a metal band) you could cut short strips and bend them 90 degrees in a vise.. for making "inside" runners for the skis that would be virtuously un-noticeable, durable and bite into the snow/ice. You could put an "edge" on them too.

Speaking of "fun" scale... if this is to be a radio-controlled model (hint) it would be very cool to put some thought into lighting. The subject is an emergency-response vehicle.. right? A 6V LED flashing beacon and head/running lights would make for a model that you could really enjoy.. even after dark! Power off your receiver battery. This could be a very lightweight RC craft if you use nano-servos and a LiFe receiver pack.

I really like the idea of this model Lieven... I've wanted to build a snow-car for some time!

Hi guys,

The wooden ski construction is a bit complicated. I was thinking of using aluminium stock of 35mm wide and 250 to 270mm long, 2mm thick. The plan of the sowplane on Kirt's site indicates skis of 13" long (330mm) and approx 1"1/4 (45mm) wide.

The past weeks I've been on and off making the engine pod of plywood. It has to contain the bellcrank for the throttle connexion. To determin the exact spot where to fix it and in order to check the throw, I made a balsa bellcrank pinned to the outside of the pod.

The engine pod will be bolted to aluminium strips epoxied to a plywood bulkhead.

A little update with pictures of the construction in progress.

OVERLORD wrote:A little update with pictures of the construction in progress.

Looking GREAT Lieven! Is it possible to vertically "slot" either the front or back holes in the alum. bracket? I ask because I had mentioned previously; that aiming the engine "down" would provide some "up-thrust".. and possibly help to lift the rear of the craft.. and make a single front ski more effective for turning. You could also accomplish this with a wedge-plate in between the engine/firewall. It appears that your running the throttle linkage up through the bottom of the pod.. with servo down below? A nano-servo like a "Great-Planes/ElectriFly" ES50 would be perfect for a throttle servo. Weighs 9gr. and measures 22 x 11 x 20mm... which "may" be small enough to fit up in the pod and simplify the linkage. If you mount your radio/battery up front.. this should help the steering-ski to be more effective as well. Maybe you could add a small weight-box up front too?

The aluminium brackets are threaded for the 4mm bolts. The holes in the wood are a bit bigger so I can move that a little if needed. If the worst come to worst and the thing does not move or doesn't steer, I can always make a new different pod that fits onto the aluminium brackets. I will create a caster angle for the front ski to give stability and to make an easy return to the straight ahead position. The model decribed on Kirt's site also has a caster angle built in.

That servo is indeed tiny and would fit in the engine pod. Now, I don't know anything about compatibility of servo's and radio gear. Could there be any differences? I will make trials without radio gear first and experiment with weights and weight distribution. I still have to buy a new up to date radio as the one I have is an antique one from the 80's on 27 Mhz.

I finalyy found some time to design the rear slis and attachments. The skis are mase out of 2mm thick aluminium. I made the bent by means of our stair banister. Then I cut the aluminium in the middle of the bent. That way,  I immediately had the front end of 2 skis. The brackets were made out of angle profile. Brackets were glued to the skis with époxy after roughening the aluminium with sand paper. I made 2 parallel lines on my building board and taped the skis onto that. I then inserted a carbon fibre rod into both pivot points.









Lieven

PM sent

Thanks for your comments.

I made the front ski and cut the carbon fibre rod to size. A few pictures of how it will look like.

cool looking model reminds me of the machines they made in the 40s and 50s over here in canada for taking people out ice fishing some are still being used they have tracks on back though hope to see more pictures as it progresses!

Thanks Craig.

Some progress on the snowplane. I made the brackets for the front ski with the hinging point. The 4mm Wheel collars for both sides of the aluminium brackets are not fitted yet. The brackets are glued with époxy. The large brass tube in the picture is only there to keep an equal distance between brackets. The front steering assembly has a spring fitted.The steering shaft is a carbon rod that turns into a brass tube. The bottom hinging assy will be glued to the carbon rod. The brass tube is held by 2 squares of 10mm plywood glued together.

So nicely done, right down to the coil-overs.

Man.. that's really looking great Lieven!