I have finally got all the major work done to get my ARF Profile Pathfinder ready to fly.  The weight checks out at 50 oz or 3#2oz.  
  Is that a decent weight?  I have an OS LA 46 for power.  So far the engine is unmodified other than a CL venturi installed in place of the throttle assembly. Venturi size is 0.275.

  What prop would be a good starting place?  I plan on running 10%nitro, 22% oil .  This ought to be a good learning experience for me as this is the biggest engine I have flown in stunt.
  Any other good advise???

  Bigiron

Marvin,
Your not overweight. Seems to be fairly typical of most of them to end up somewhere around there. Mine is just about the same as yours. Box stock, OS46LA Zinger Pro 11/4, Nelson lite fab covering, Rustolium trim. It's several years old and has delivered lots of flying. It does a better pattern then I, but al I care about is the pleasure that it brings me.
Dennis

Marvin,                                                                                                                                                                                                     As you know I have a Pathfinder built from  Brodak kit.  Power is an LA46 with a .281 venturi and a ST needle valve. I have tried every prop that I have that would be suitable for this engine and the Thunder Tiger Cyclone 11x4.5 was the best by far. The APC 12.25x3.73 is also a very good prop for this engine but the Pathfinder does not have enough ground clearance to use it.

APC 12.25 x 3.75 is a VERY solid prop for the LA 46.
we dont cut them down, if you need another 1/2 inch clearance, put on bigger wheels. The prop really works well, especially with the venturi size you are using, ( assuming you are using a ST style needle assembly?) 10-22 fuel is a good choice too. I launch mine around 9700 to 9800 depending on how your tank is configured as a wider tank will lean out a touch after flight speed is reached.

Marvin
I would try 11x5 zinger and if you are near sea level I would add a head gasket..
Willis

Willis,  May I ask what size Saito and 3 blade prop you are using on that nice looking Pathfinder?

Regards
Warren

   Got all the props except the Thunder Tiger.  Where do I find that one?  Got two of the APCs so I can cut down one of them.

  Now to get some good weather.

  Bigiron

John
That is a good question. Let me say the Pathfinder doesn't really need larger elevators this goes back to the red  Cardinal. Mike Garmon built one of the first pre  produced Cardinal kits and I used the planes to build me one. Mike and I agreed that the plane seemed to drop its nose or hesitate before square corners We thought that the flaps were to big  causing this. ONLY OUR OPINION. Mike moved the push rod up one hole to make the elevator move more then flaps it made the difference from the worst plane that he ever flew to his most favorite. His words. On Mine I added half inch to the elevator and put the landing gear in the wing the plane flew great . I built several Cardinals after that and all had that modification. The pathfinder was built during this time that is the long winded reason the elevator  is wider.
A few years ago I bought a ARF Cardinal and I  thought it had the same problem so I cut about one third off the flaps and TO MY OPINION cured the hesitation. I gave the plane to Artie Jessup and for the two years he has cleaned house with it .
As for the Pathfinder the only weakness I see is the fuselage is week on the ARF and the stab will twist up and down  in the maneuvers. I fixed mine at the field but the rear of the fuselage needs to have some one sixty-fourths plywood down each side. Just my opinion.
Willis

John
Like I said I fixed mine at the field. I twisted the elevators opposite what the tilt was in the air.  Don’t laugh it has worked for eight years.
Willis 

John,
I did the same thing on my Gee Bee profile after a long talk with Pat about this. The Gee bee has a LOT of horizontal area and I thought it would be prone to twist. Ultimately, it didnt really twist all that much especially after I did your silkspan trick under the monokote.  but I certainly didnt see any harm in that.