Guys, The rcs140 is an awesome little engine but its definately too small to go into the WM mustang or the 1/5 pica mustang. Its absolutely perfect for any of the .60 size warbirds like the top flights. It weighs the same as most 120 4 strokers and the added weight of the ignition battery and module is more than offset by the reduction in fuel needs. I used to fly my 120s with at least 16 oz of fuel to get a 10 min flight. We can all figure out that translates to lots o coin in fuel costs. The rcs only needs a 10oz tank to go 15 min and the tank can be placed over the CG to get better weight distribution. RCS offers a rear exhaust version that is perfect for even the slimmest noses of inline warbirds. All you have to do is come up with some sort of muffler that wont protrude. I used the muffler from a saito 180 on the rear of mine in the FW190. Im up to around 70+ flights on my fw190 with the rcs and it gets stronger every time I fly it. Currently its turning 9500 on an apc 16/8, really flies the crud out of the little Dora.
Heres a pic
Evan Q.