Well, let the question of whether a PA .51 on a pipe is enough for a Strega. Its way adequate power. 11K rpm gives a 5.3 to 5.4 sec lap with 5% nitro at about 48 degrees air temp . First flight was outboard wing high so I only flew level. except for a brief inverted excursion to check the shim which is close. A little slower inverted, but that will be easily adjustable with a uniflo vent position change.
Second flight I did with only 4 oz of fuel so I could check the flap tweak. Using Bob McDonalds adjustable flap horn is wonderful, but moving the entire flap really requires small adjustments. I went way to far on the first adjustment so the second flight was another level flight only.
Third flight I had the flap tweak about perfect. I do have problem hearing the needle accurately at this point with the pipe, my first stunt motor on a pipe, and the third flight went off too rich, about 6 second laps. Not enough to do much more than inside loop and a few inside squares. But there are a few things that are readily apparent. The plane flies infinately better with the light 2 stroke motor vs the heavy Saito .72 I used on two stregas last year even with 1 3/4 inch chopped off the front of the plane to account for the weight. The plane requires much less control input for a given maneuver than with the 4 stroke motor. I am not trying to detract from 4 stroke motors. I'm just stating what the differences are that I have seen so far and were very apparent even at early trim stage. Granted I am at just basic flight trim but the corner was much more defiante than with the .72 and and hard full control throws are not required with the lighter two stroke plane. The plane with the PA .51 is very tunable and should work out pretty well. It is however, really butt uggly in the air with the pipe hanging way down. I was able to build in a tunnel for the header, but the pipe hangs out in the breeze as it was not designed for a pipe. I started with a 12X4 bolly 3 blade carbon prop and it seems to work well as a startging point. Line tension is ... noticable. What you would expect in a .60 size ship, not the light on the lines feel of a .35 size plane.
I don't know how other .51's on pipes perform. Randy Smith had told me the PA .51 on a pipe would generate considerably more power than a ST .60. I think its just another viable power option on the Strega ARf/ARC. I happened to have one on hand for another project and decided to give it a try. Others may as well. There is a build thread on the mods I did on the AMA district VII forum under the control line building forum, but there isn't really alot to it. The mods on the Strega are pretty well known for opening up the front end for whatever muffler, header you want to use.
bob branch.
Topic: Strega ARF with a pipe (Read 1147 times)