Hello, I have currently been building a Yak 54 with a 40cc engine. I am having trouble figuring out a way to make a good template for the cut out around the engine. I will show a pic of another but similar airplane and engine. I don’t want to screw it up so I am looking for any ideas on a way to make it easy. Thanks

well measure a square around the engine itself.

They draw the square on the cowl. Make it smaller then it should be then put the cowl on to see what more needs to be cut and expand teh sides that need to be cut.

Hope this helps..

To do it exact is a pain.
Install engine and then a piece of card board attach to the fuselage.
Draw the outline of the engine and muffler on the card board.
Remove the engine and install the cowl.
Remove cowl material where it is outlined on the card board.
Re-install engine and installed modified cowl.

gapple12,

What Geistware posted is what I do. Start with small holes and cut a little at a time. It takes a long time but the end result shows your effort.

Zippi, why did you baffle your yak? was your engine overheating, or you just did it to be safe? I heared with yaks and small single engines baffles are not needed. is that true?


thanks


Ahmed

xtdsm,

I didn't baffle the front of the cowl, it came that way. All I did was make the cutout for air to pass over the engine. You have to be careful not to have to big of an opening because you could get to much air coming in and no place for it to go out. Some times guys will block the front of the cowl off if they are having heat related problems but I want as much air as I can get passing over the engine with the smallest hole that I can get away with. My QQ YAK 54 73" has not been flown yet so I don't know if I have a heat problem or not. I shouldn't have with the head of the 40cc and muffler exposed the way it is.

thanks a lot Zippie, the reason why I asked is because I have recently started learning to hover and harrier, and now my DA50 runns a bit hotter than my likeing, so I was thinking to cover the front of the cowel and leaving an oppening for the head, then that kindda worried me because the ignition would not cool down as it does now, and that would be another reason for dead stick. so now what I do is hover for a bit then fly around to cool the engine down. that seems to do the trick, but I would really lover to be able to hover for longer without worring about the engine overheating. one more thing, the weather here is still so damn hot (around 35C-40C) so that might be another reason for the heat problems.

thanks

Ahmed

I do as Geistware suggested but I use clear plastic sheeting (window/windshield material purchased at hobby shop) instead of cardboard.