Model Forum / Radio Controlled / Air Models / February 2004

This is related to my other thread "need engine recommendation".   I
have a collection of FP engines, several in each size from 10 to 60,
leaving out only the 35.  I recently built two identical Small Wonders
(15 size parasol wing from RCM plans) for myself and a friend.   I put a
15 FP on mine and a 400 MaH NiMH battery.  My friend put the  MDS 18 and
a standard NiCad Rx pack in his.  

I don't like to spend money, so I don't go nuts on small radio
equipment.  Both of us used three standard servos for these planes.  My
plane weighs 36 oz ready to fly, and his weighs 44.  I'll estimate an
extra ounce or three for his aluminum gear and axles compared to my wire
gear.  I weighed the batteries, and his weighs 2.5 oz more than mine.
The rest will have to be attributed to the engine.  Although the size of
the head and cylinder look the same, the MDS has a bigger carburetor,
bigger muffler, and ball bearings.  You may think that it's all the same
either way, but that's just about a 20% difference in weight.  My plane
has the same rate of climb and is noticeably more maneuverable and less
oily.  His plane flies great, but I prefer mine.

I really liked the MDS, though.  It was quiet, very user friendly, and
it spun an 8x6 prop nicely.  I'm thinking that maybe it would be a fine
choice for a 20 size plane, but clearly it was out of my range for the
15 size plane.  

I just thought that this was an interesting comparison for anybody who
wants to consider different aspects of engine performance.