YS 63 question
 

Hi Troy,

The 63's are running very well in the P-61 and it looks as though I can count on a 10 minute flight on 11 oz tanks as long as I don't rip around at full power all the time. This is allowing me to land with about 1/3 a tank left on each side. I now have about 18 flights on these engines. I have been using Wildcat 20/20 fuel and OS F plugs. The last 3 flights I used the Wildcat 30% Curtis Youngblood Heli blend and it seemed to run just as well. I have not had to fiddle with the mixtures at all since the test flights.

Now the only oddity I have noticed is with the right engine.
This is the second engine that I start each time I fly the plane, due to safety concerns.
I have noticed that once I have started both engines and allow them to warm up for about a minute, as I do the first run-up to full power ,with gradual throttle movement, the right engine seems to bog and stop increasing RPM at which point I reduce power.
This only happens the first time. If I come back to high idle and then power up again it does fine and syncs in with the left engine OK.
You can hear the bog in this video at about the 30 second mark as I do my preflight run-up.
http://www.rcuvideos.com/item/YQZMCV2QLV180DM2
Could this be to the fact that the right engine has not had as much time to pressurize the tank as the left? Since I always start the left one first. There is only about a 10 second delay between starting the two engines.

This is a consistent situation that has caused me to check for it each time I start up.
Prior to my last flight I backed the regulator out about 1/8 turn to see if this would help a bit. It didn't seem to make any difference

In all other aspects the engines run perfect! They are both pulling a nice stream of exhaust smoke behind the plane and the only time they have died has been when I run the plane out of fuel. Which I am really trying to avoid doing.

Thanks

RE: YS 63 question
 

Try this....to prove its a tank pressure thing.


When filling the tanks....After its full put a little pressure in it with your fuel pump. Connect the check valve however you have the plumbing setup...and just put a few extra cranks like 4-5 in the right engines tank. If its a electric pump just a couple quick bursts.


This will Pre-pressurize that tank and it might help the situation if it truly is a tank pressure issue.

The other option is to start the right engine and run it alone checking the settings. It could be a little rich or a little lean...something tough to see or actually hear when both are running.

from your video the engine sagged out lean. Does that mean it was lean from the lack of pressure or was it just a smidgen lean on the mixture...I suspect you are correct about the pressure build up.

I would not says it rich...a rich setting will slowly build rpm. This one speeds up and then sags out. If it was rich it would just come up slowly building rpm.

So try the pressure deal and I bet you have it solved.

Troy Newman
Team YS

RE: YS 63 question
 

That sounds like a good idea Troy,

I will try to pre-pressurize the right tank on the next flying session.