The mixtures are fine for WOP up to that 15.1. I only know mixture from EGT numbers so anything short of 1600 degrees is just fine for full power with little chance of damage.

 

The advance is used to get peak cylinder pressure at 50 degrees after TDC. You can see this as a peak RPM while changing nothing but timing. Peak cylinder pressure is a function of everything including your hat size and the direction the nose is pointed. So you dial it up from peak rpm, and then back it of just a bit. Always at or just below 1600 degrees.

 

The RPM so far are nearly fast idles. Remember 20 degrees of advance is plenty to get to 9,000 RPM on 93 octane pump gas with no alcohol. If you use 110 avgas then 22 degrees is a fine starting point. the lower the RPM the less advance is needed. Advance is a time function. Lower RPM means more time for the burn and less advance is needed.

 

So at each 100 RPM both advance and retard timing from the set point to see that you are in the middle of a range for that RPM. You may find some nulls that like a bit of retard. This is usually a combination of header and inlet tract design. Your combination is not like anyone else even if they look identical.

 

Cylinder pressure developed BTDC subtracts from torque, so less is more in the timing department.

 

Target water temp is 180. Oil temp is 160. Above 160 oil is giving away power, as rotor face temps go way up and limit charge volume. So, oil temp control is free HP.

 

Fuel cooling for takeoff and climb is no sin. Piston engines need to do that every time. A better picture will be available during high speed testing with a bit more RPM and air flow in the induction system.

 

1600 degrees goes with about 12.5 FA in most cases.

 

Advancing the throttle from fast idle to full power should be smooth and slow. If the timing is fixed this is very important. For closed throttle and near closed throttle, with poor cylinder filling fixed 20 or 22 degrees is fine but if you romp down on the power quickly that 20 degrees is way to much as wide  open throttle at low RPM gets you nearly 100% or slightly more cylinder filling. So that is where you can chip an apex seal or overload a rotor bearing. I could not get this across to my driver, and thus developed a collection of pricey chipped carbon race seals.

 

Record everything.

 

This information may be worth what it cost you.

 

Lynn E. Hanover

 

 

 

Today I ran a while to let the computer tune the engine.  With the brakes set, I averaged probably about 4gph for the first half and 1.5gph on the second half of the 12 minute run.  I finally had to stop when the water hit 200*.  The oil hit 175* after 9 minutes and only got up to 181* by the end.

I then did some wide open throttle runs.  The computer was all over the place in this area, becuse I've done practically no tuning runs there.  So, these runs were to get data on where the engine wants to be as much as it was about listening to the engine scream.  Its hard to pick meaningful data, because the computer has the engine jumping around, but a few samples:

TP   RPM    AFR   GPH   ADV
62   5043   11.5  18.11 22.2
73   4579   11.9  19.52 20.1
50   5014   15.1  14.75 23.4

I'm definitely making good power, evidenced by the curtsy the nose does when I power up.  Anyone care to guesstimate how much?

I don't think 12 minutes of ground running before hitting 203 is that bad(?).  The last 8* took 2 minutes.  The graph was fairly flat at that point.  If I raised my water temp redline to 210*,  I'd probably not ever hit it.  OAT was about 80* today.

At this point, I think my goal is to see how far I can lean out the low end,  while working to smooth out and then increase power on the top end.  I also think a lot of the timing could use more advance. 

Comments? Advice?




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