Hi Mike !
All valid concerns, and quite correct ! The Rebel actually is a
beautiful airplane with the Rotax 912 (and 912-S would be nicer !),
and is all the airplane many people would ever need. However, there
are always those who want to push the limits, for ultimate performance.
While <I> think the Rebel would be a nice floatplane on Murphy 1500 amphibs,
with a Rotax 912-S, there's no doubt that a Rebel with a good XP-360
on Murphy 1800 amphibs would likely perform a little bit better ! ;-)
<I> would NOT use a STOCK Lycoming O-360, either new or re-built -
these engines, with metal props, have an "AVOID OPERATION" range from
about 1900 to 2450 RPM, because of vibration (the crankshaft flexes !!) !
This would force you to fly perhaps faster than you would want to in
rough conditions, and risk the structure.
The other problem is weight - a stock Lyc. and prop would be much
heavier than an O-320, likely giving C of G and firewall problems.
Pierre's setup is quite different, and not tooooo much more expensive
than a rebuilt Lyc. - my recollection is that it's a NEW Superior XP-360,
that was refined by Ameritech (Eagle engines) - balanced (very important !),
polished & ported, etc., with dual Lightspeed electronic ignition, a custom
lightweight carbon fiber intake manifold, fiberglass plenum for cooling
air flow, dual lightweight alternators, (one at the back of the engine),
etc., etc. ..... There was NO published RPM range limit, and the engine
runs VERY smoothly !! (I'm still not a big fan of injection, but
it should give better fuel distribution.)
The Prince prop is a wood core, with a metal leading edge strip,
and carbon fiber coating, weighing about 9 lb ! It has an "Almost
Constant Speed" design that changes shape with load, to give good
climb AND cruise. With the light weight and low inertia, it
absorbs power pulses well, and runs smoothly - a good combination !
I believe the tail mods on the Moose were mostly done because
the 2 bladed paddle props (10" chord !) on the M-14 sent huge slugs
of air back at the stab, greatly adding to the twisting forces -
- showing up quickly in accelerated metal fatigue. The Elite tail
shares the stinger mount problems of the Moose, so has concerns too.
Don't recall problems with the Super Rebel with the O-540, or IO-540,
with thinner props - not that they might not have shown up after
many more hours .... In any case, the strut-braced stab on the Rebel
seems to work quite well, and there have never been any problems
reported there.
One final concern with more power is speed - I was VERY worried
about getting up near VNE, as this DOES endanger the structure. This
proved to NOT be a problem - between the prop being way too fine,
and the drag from the vg's, there was NO danger !! :-) Even with
the right prop, anyone going to this engine would be going onto
amphibs, so the extra drag there would take care of any excess
speed worries ! ;-) :-)
Just got off the phone with Pierre - he agrees with my first
paragraph ! If he could start all over again, 3+ years ago,
he says he would build his Rebel with a Rotax 912-S and
a variable pitch prop, keep it light, and put it on
light Murphy 1500 amphibs -
- and be very happy with a great, economical, fun float plane !
To be honest, if I'd known it would take me < 5 years > to get
MY Rebel set up, with an O-320, finished, on Murphy 1800 amphibs,
I would have just built what <I> want - that light, 912-S powered Rebel !
Now, I have to start on it next year ..... :-)
.....bobp
-------------------------------orig.-------------------------
On Tuesday 06 September 2005 08:54 am, Jones, Michael wrote:
hi all
after hearing about these new rebles with 0-360 engines i am wondering
about
the greater structural stress being put on the rebel ?? when the factory
did
upgrades to super rebel creating the moose there where big changes to
handle
the extra forces, as i recall the tail was strengthened and other areas.
does it not make sense that the rebel with 30 or so more horse power than
a
0-320 powered rebel would need some structural additions ??
i was looking at 0-360 and looked at drawings of the elite and its tail
structures, seems the elite has much stronger tail mounting than the basic
rebel so i decided it was bad idea to put 0-360 in a rebel, is no one else
worried about these structures fatiguing over time and failing, what about
that little trim tab bracket ??
just me 2 cents
mike#007
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