So far, I had tried a 12 x 6, 13 x 4,
and 13 x 6 prop on the RCV 58. The 13 x 4 had worked the best in terms of
climbing and I was getting about 9500 rpm. Friday, I tried an Airscrew 13 x 5 and
have now proclaimed it the best over all prop for this engine. Climbing vs. speed
was good and I got about 9200 rpm.
 
During the first week or two of this evaluation, the plane would barely climb at 45
degrees. Now with the combination of the engine being well broke-in and the use of a
13 x 5 prop, the plane will climb out of view at nearly vertical. Fuel economy has
also been excellent. The stock fuel tank in the 40 size Ultra Stick yields about a
25 minute flight.
The RCV 58 has been trouble free except for the loss of a carburetor screw as mentioned
earlier. Performance continues to increase and there have been no dead sticks in the
past few weeks. One of the most commonly asked questions about the engine is about
the sound. It does have a higher pitch than most other four strokes but it does not
have the pinging metal sound some said they had heard with other RCVs. Another
observation is that I have not had to readjust the high or low end once the break-in was
complete.
With around 20 hours of flight time on this engine, I would feel confident in recommending
it to anyone who would like a very compact, smooth running engine to install in a light
weight 40 size airplane. Keep in mind you will have to allow for a fairly long
run-in and be prepared to experiment with several props to find the perfect performer for
your particular plane. You will also find that the wider mounting hole pattern will
cause you to have to customize your engine mount. When I built the Ultra Stick 40
for this review, the stock mount would not work. The Sig Glass Filled T-Type engine
mounts for extra large engines worked very well.
This will be my the final post concerning this review unless anyone has questions of if
something drastically changes mechanically with the engine. I appreciate Mark for
allowing me do the review and Walt for letting me know they were looking for someone to do
the review.
More to come... from others (I hope)
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