One of my most successful and entertaining R/C toy upgrades so far is a Silverlit iWingz ornithopter (aka Air Hogs V-Wing Avenger), that I fitted a Deltang DSM2 actuator receiver in, from
deltang.co.uk. The receiver weighs about 0.4g, or a bit less without connectors.
Silverlit iWingz with 2.4GHz DSM2 DT / Deltang actuator receiver (2CH proportional)
The Silverlit / Air Hogs ornithopters are pretty good already but the infrared remote system has obvious limitations - very poor range in certain circumstances, like outdoor lighting or the bright lights inside a sports hall at an indoor fly-in.
Wiring up the Deltang Rx was by no means easy - at least not for me, even though I bought it with sockets fitted for micro connectors. My hands are very unsteady, and the wires to the rudder actuator kept shrivelling and getting shorter as I tried to solder them onto a plug.
Anyway, the end result was good, and it's flown at quite a few indoor fly-ins since.
The DelTang DSM2 receivers have been mentioned many times on rcgroups, and can be posted to anywhere in the world, as I understand it. There are a bewildering number of choices for different types of models, servo versions, actuator versions, multiple forwards only and H bridge (fwd/reverse) built in brushed ESCs etc.
They are incredibly small and light, and are made by a talented individual (
DavidT), not a big corporation. Well worth a look:
www.deltang.co.uk
David has been very helpful in explaining the various options, and personally soldered the optional connectors onto my receivers at very little extra cost - something I'd never manage to do myself.