2 channel R/C Question

[Guest]

I've got an old two channel Futaba transmitter and currently I'm using it to control my own scratch built Tank chassis.

I want to add turret rotation / gun elevation and possibly a mechanism for a electronic Airsoft BB Barrel, obviously I'm already using one channel for throttle and one for steering.

I've noticed on a lot of cheap r/c tanks they use a trim tab to swith between the two channels for throttle / steering and turret rotation / gun elevation. Is there any gadget I can add which will allow switching in some way like this or do I just need to go out and buy a 4 or 6 channel R/C setup?

Also how would you control things like headlights and gun firing?

Sorry for sounding a bit thick but my experience of R/C only goes up to running a Mardave Meteor about 15 years ago!

[Guest]

Alan, whilst it may be possible to do what you say you are then stuck with your controller only being capable of doing either one thing or another. So with a tank for instance you would have to stop to rotate the turret.

I am sure that you would very quickly become frustrated with this setup, and lets face it the only reason this type of thing is used with the cheap R/C tanks is because they are cheap, and with the cost of three or four channel sets still being relatively cheap nowadays I wouldn't hestitate to go out and get a radio that will do the job properly.

Even a six channel Hitec or Futaba wouldn't set you back much more than 100-150 pounds so it's just not worth the hassle and you will end up being frustrated with your model if you don't.

Bear in mind of course that if you buy such a radio you should be able to use it for more than one model with the addition of some receivers and servo's so it is money well spent.

I actually have a three channel Hitec that I use for four models now, just change the crystals and away I go.

[Guest]

The only thing is can I justify the outlay of 125 quid or so just to annoy the cat and drive tiny tanks around the front room?

Although the look on the cat's face as it reversed away from the approaching tank was priceless!

[Guest]

you could always look at the second hand market or flea bay... ? but i would say 4 or 6 channel is the way to go !

[Guest]

The only thing is can I justify the outlay of 125 quid or so just to annoy the cat and drive tiny tanks around the front room?Although the look on the cat's face as it reversed away from the approaching tank was priceless!

Definately if you bear in mind that you can use the radio for other models in the future.

Apart from that it is definately worth it when the cat lifts up it's tail and the BB pellet hits the middle of the target!!!!!

[Guest]

EASY!!

using the trim tabs you can turn the servo horn an extra few degrees.

if you go to maplins or halfords you can get push buttons.

put these infront of the servo horn in full throw with the tab in the centre and fix into this position. so when you push forward the servo horn doesn't make contact with the button but move the trim tab forward and.... you have just shot the cat!

[Guest]

Most of the RC Transmitters on Ebay are 6 channel for Aircraft and Helicopters 72mhz , can these be converted for Land use?

[wonwinglo]

I do not think the conversion costs would be worth it,the circuitry can be quite different.

[Guest]

EASY!!using the trim tabs you can turn the servo horn an extra few degrees.

if you go to maplins or halfords you can get push buttons.

put these infront of the servo horn in full throw with the tab in the centre and fix into this position. so when you push forward the servo horn doesn't make contact with the button but move the trim tab forward and.... you have just shot the cat!

Wouldn't that mean the gun would only fire when the servo for the gun elevation (for example) was at full throw though? Might make it hard to hit anything then.

[Guest]

Alan,

As you probably know 72Mhz sets are not legal in the UK so not worth bothering with anyway, but in answer to the rest of the question, yes you can fit switches to activate on a given throw on 2 channel R/C sets.

In your case for the tank Barrel, set the switch so it engages on a given elevation to give the best result...this can be adjusted of course to what you are happy with.

I have watched R/C Jet Videos where they employ full brake on the Undercarriage by using full down elevator. When the elevator is released, the wheelbrakes are off too....very handy when spooling up the engines !!!

Regards.......Mark.

[Guest]

Sorry - I actually meant 35mhz and not the 72 mhz US frequency.

Is it possible to convert 35mhz transmitters to 40mhz? And any idea's who'd be able to carry out the conversion, ripmax or someone?

[Guest]

HI Alan,

To be honest, for what it costs for a 40Mhz set these days, it is probably a cheaper option to buy a new set. I have no doubt that a conversion could probably be done but the cost would more than likely outweigh it compared to buying a new set.

I have no idea who does the conversions though.

If you don't use the 35mhz set anymore why not sell it and use that to fund the new 40Mhz set.

Regards....Mark.

[Guest]

Wouldn't that mean the gun would only fire when the servo for the gun elevation (for example) was at full throw though? Might make it hard to hit anything then.

Alan,

there are electronic gizmos that give you more channels from 1 but the most elegant (and cheapest) way I have seen is to use microswitches on the servo horns. When at full throw it can switch the other channel to a different circuit which gives you three channel. Wire up and bypass your speed controller and you can have 4 but the last two are single function at a time i.e. Full movement throttle and steering OR move the turret OR shoot the cat.

How big is the tank?

Microswitches are the way to go but you could be cramming a lot into a small space.

James