...Info please...

[Bootlegger]

   Guy's Yesterday I was runnin' my RO Jett 40 rear exhaust with a 11.5x4 APC prop on 10% 11&11 oil and started with 5 oz of fuel. Timed it at better than 9 minutes, cut to 4 1/2 oz same fuel got over 8 min then 4 1/4 ox got over 7 min.
  Is this normal ?  The engine is broken, or has about 1 hr to 1.5 hr on the bench.
  I am not complaining, but I sure am curious.

[captcurt]

Thats not far off my own experience with the BSE 40 on a header muffler in my old Vector40.  I ran with a filter on mine also.  It would burn more if the venturi was opened up.

I ran my mostly 4 stroking along and breaking nicely into a two stroke up high.  10% was used when it got hot only--most of the time it was 5%. 

For high density altitute days, try an apc 11 x 5.  It seems to give alot of bite in the hot humid days. (Thanks to Dave Hemstraught)

Curt

[Bootlegger]

 Kurt,
 Thanks for the response. I failed to say that I'm running a muffler instead of a pipe,and that the tach was showing in the range of 9300--9550 rpm.
  It still has the break in plug so that will be changed to a T bolt lont w/idle bar when it goes in the model.
 I also don't run with muffler pressure instead open to the atmosphere on the vent.
  I'm looking forward to getting it installed in the new model.
 Again thanks for the info   

[Randy Powell]

Wish my Ton Lay OS46VF had that kind of gas milage. I had to put a "wart" on the front of the tank to extend the capacity to a bit over 7oz to have enough fuel to finish the pattern. This with a .270 venturi. Man, what does Tommy do to these things? Sure has plenty of power. That's certain. I can tell you I was pretty shocked when I filled the tank (6.5oz capacity) and ran out of fuel in the overheads. Yeow!

[Bootlegger]

 What about restricting the venturi by about .010 and see what it does for power and milage ?? Might help both ...

[captcurt]

With the four pitch prop, you might need to run it a bit faster RPM in a plane so that will get you down a little on fuel.

Mine was the small insert muffler put into the end of the header--simple and effective.

And the engine will continue to get better as it fully seats in--perhaps over a couple of hundred flights.

Randy:  Wow!  7 oz!!  Well, around here we say that fuel burned is horsepower made.  One of our group just put a 9 oz tank into his PA75 setup.

Curt