Tow plane build.... Anyone ?

[Fred]

Hi there,

Anyone interrested in building a Tow plane ?  :?:
I have made a plan for one, all wood, easy to build, basically, a big trainer.
2.4m WS, for 26 to 50cc engine, or even better, electric power.

I will certainly start it later this year, but if someone is interrested now...
I'll post a 3 views later.

[billscottni]

I was thinking of building the Bostok that you printed for me, later this year (after Retroglide!), for a LARGE electric motor.

[rogallo]

My dynaflite Super Decathalon is nearly finished. fit the tank and release servo and I am done!  

[Fred]

Aaahhh good to see some tow planes coming around !

Still have to finish the covering on my BigLift.. But need a backup tow plane, especially if we are going to organize towing meetings.

So here we go, 2 views of the new one   :



A box, shaped like a plane, with wings  :mrgreen:

WS : 2.4m
Fuselage : 1.75m
Profile : Naca 2412 with Flaps

Will build it at some point this year

[billscottni]

Taildragger version looks nicer than the trike

[Alan_Perse]

I like the name.   Looks great though.

[Fred]

Yeah, I'll go for the tail dragger too, all my previous tow planes (except my my piper) were 3 weelers... And the front wheel always gave /generated problems !  :!:
Or must have worked my landings better  :roll:  

[Happy Days]

Turning to the matter of Electric power for this little monster………..

I have an airframe of an 85” span  Clipped Wing Cub. (I was given it after it was involved in a mid air collision)
I took it on the basis of repairing it and fitting an outrunner motor in it. But when I came to cost it all out I couldn’t afford it………………..

An out runner and ESC that produces power equivalent to a 25cc petrol engine is………quite expensive.

Add in the cost of flight batteries which would be of, say….. 5 - 6000mAh. capacity.

Now you have to factor in the cost of a charger that is capable of recharging those batteries in a reasonable time.  Let’s say a 22v flight battery set up charging at 4C would need something in the order of a 500watt charger.  That wouldn’t be cheap.

Then you have to come up with some way of supplying the power to the charger. i.e. either a couple of large RV batteries, or a small portable generator.

All this, to get one plane in the air.

Though it hurts me to say this, because I hate the noise of model aero engines, but an internal combustion power source is the only viable way to go! :!:

Wouldn’t you agree?

[JohnPearson]

I agree with you keith, I.C, is the best with to go and cheaper. Our club just sold a tow plane a few months ago £100, just drop in an engine and go, however, there are a lot of big models appearing on the BMFA ads section of their website over the last few months, maybe we could pick up a cheap model.

[billscottni]

I dunno guys :?:

If you want ballistic climb rates and to tow huge models,yes maybe IC is required.

BUT.

We are a QUIET hobby! Gliders are far more aerodynamically sound than the average IC model, they fly on the wing not the prop, so only need to be moved at above their stall speed to provide lift and get them flying. Then a nice gentle, relaxing climb to height before release.

Electrics have moved on significantly in the last few years. A tug designed along glider lines, with a medium power electric set up should be affordable. Yoou can get around the large batteries needed by ganging batteries in series or parallel,, which also helps with the charging problem Keith mentioned. Most people have standard type chargers, 3 or 4 of them and the charging is covered.

Leave noisy smelly IC for the heathens who haven't discovered gliding and think flying is prop hanging and 3D

[Fred]

Yeeeeaaaaa !
Found a photo of the old tow plane  



A Bison with altimeter in the cockpit for automatic release at 200mtrs (F3I)