An air cooled version of the 'Tiny' engine that was originally designed and drawn by Arv, alias Put Put Man. My changes were to make an air cooled cylinder and a hit and miss mechanism that would really control the speed of the engine.
Nice build. I am wanting to start one of my own. How did you go about making the ignition system. I have the plans from modelengine maker forum, but I didn't see anything on the ignition system.
+Malcolm Till There are two weights mounted on a hinge joint on the flywheel. As the flywheel spins centrifugal force throws them outward. Attached to the weights are arms that reach inside the flywheel. The tips of the arms locate into a spool which slides along the crankshaft. The spool has two slots, one for the arms and one for the lockout lever. The lockout lever engages the exhaust pushrod when the engine picks up speed, otherwise it stays clear of the pushrod to allow the exhaust valve to open and close. When the exhaust valve is held open there is no vacuum in the cylinder when the piston goes down the bore so if there's not vacuum the intake valve wont' open so no fuel charge is drawn in. On full sized hit and miss engines when the pushrod is locked out it also prevents the ignition from firing.
I'm having a little trouble finding it do you have a link.. I really would appreciate it.. and nice work by the way hope to get a chance to build one myself
The exhaust valve remains open until the governor calls for power. Up until then, the exhaust valve is held open and air is going in and out with the piston movement. When the governor calls for power, and the exhaust valve is closed. The intake valve is a "poppet" valve, which has enough "spring" tention to remain closed until there is a vacuum. The exhaust valve closing on an intake stroke creates a vacuum, and the intake valve opens allowing a fuel/air mixture to be sucked in, followed by comprehension and power strokes. If the power stroke speeds up the engine enough to open up the governor, the engine will begin freewheeling again.
+Ironheart Fabrication I'll have to experiment with the springs on the governor weights. Being that it will start by hand I'm sure it will run slower. How much I don't know because of the small size of the flywheels.
