I am making a dual rocket engine, scratch built rc delta wing plane called the "Lady Hawk." One engine will be lit on the launch pad and I want to be able to ignite the second engine while in flight. While the 10 year old plan shows using another servo to push a switch I am hoping that there is a lighter electronic version that could use channel five. There will be a separate battery for the ignitor system as I do not want to drain the receiver battery to ignite the rocket engine.

I believe the easiest way would be with a nano size servo. Anything electronic that plugs into a channel would have to have logic in it to decipher the servo signals - and I don't recall seeing anything like that that would be of use to you. The weight of a micro switch and a nano size servo shouldn't be much of a weight consideration - unless the delta wing is really small.

Just a side note: you might want to check AMA rules covering rocket propelled RC aircraft. At the very least, be sure to test this craft well away from any urban areas.

Check with Precision Micro Electronics: pme-rc.com (361)814-6843 (M-F 11am-6pm cdt)
His website does not show much, but his ad in the May 05 AMA mag on page 142, lists a
"Rocket Ignition Unit". $39.95
I know Steve personally, and his products are oustanding. Just tell him, "Terry" said to call, & he will fix you up.

Where did you get a set of those plans? I would really like to get a copy of the Lady Hawk. PM me.[sm=thumbup.gif]

The plans were from the RC Modeler magazine from 10 years ago. I also have plans for a front canard plane also launched with one engine, I think it was called the sky blaster. Currently flying, today as a matter of fact, is a kit built plane called the stratoblaster from estes. Again 10 years old and it put into the air with a "E" sized engine, when I run out of rocket engines I put a little weight in the nose and a cox .049 with a pusher prop in the tail. Estes still offers the plane as an ARF only called the "Centurion" now a days.

Try this web site. Has some electronic RC switches that use a spare channel

[link]http://www.uoguelph.ca/~antoon/gadgets/gadgets.htm[/link]

Dave

You might want to try Tripoli Rocketry Assn. When I was flying high power in the early 90's (talk about your $$$$$ going up in smoke) we had several electronic switches, some using timers, and some using accelerometers, designed for inflight ignition. They were very small, and used a 9 volt garage door opener battery for power, very light weight. I haven't kept up with the stuff, so 15 years later, they should have even better stuff. They also had some neat altimeters that would register max altitude (AGL) attained by measuring the change in atmospheric pressure between the launch site and apogee. My personal best BTW, was 9850 feet with a 1/4 scale Honest John and a L motor.

krueg,

You could use an on-board glow driver. Since its basically an electronic switch, you could slave it to a switch and just flip it on when desired in flight. Fairly light and you should be able to get one fairly inexpensively.

Duke

If you have an unused ESC they can work well as igniters as well.... If you use an esc with reverse and forward you can fire both engines seperately using a couple of diodes. They work really well and don't have the mechanical problems of servos and switches.

if you don't want to have to ignite the second engine manually you can make a two stage rocket. You can make it have a delay too if you want. You do this by taking two rocket engines (the first one sould have a delay time of 0, this is the last number, if you want it to ignite right away) you put one engine on top of the other so that the bottom of one is matched with the top of the other. You then take tape and wrap the two engines. This makes it so that when the engine fires the recovery stage it will ignite the second engine. good luck.