hey all what is the name of the engine that has a piston that moves front to back (in relationship to the firewall) rather than up and down or left and right.

It's an RCV engine, the "SP" series...it's funny, as i was reading the post, there was an add for RCV engines right above it

[link=http://www.rcvengines.com/rcv_modelhome.htm]RCV engines[/link]

outstanding hey are these engines any good

The engines are doing very well with few problems.

There are two unique features of the RCV SP engines that lead me to selecting it for my Top Flite Spitfire build. First, it's streamline design fits well inside the nose of the Spitfire, with minimal cuts to the cowl. Second, the engine is internally geared 2:1 which allows for the use of a much larger than normal prop.

In my case, I further minimized the cutting of my cowl by the addition of a small electric ducted fan to provide cooling of the engine. This allows for drawing air in in-between the spinner and cowl, with baffles inside the cowl to keep the airflow against the cylinder, and only an exhaust hole cut at the bottom of the cowl. It also allows me to use a close to scale 15.5" diameter 4 blade prop. I've run ground tests for the past couple of weekends. The cooling system is working very well, even better than I had hoped, and the power seems to be sufficient for this plane with a final weight of 10 lbs, 10 oz. I am planning on a maiden flight on Sept 16.

Here's a video clip of it running on the ground with the cowl off.

http://www.youtube.com/watch?v=ZpwJ0XYTeIU

Scott