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murphy-rebel@dcsol.com at 20:31:11 on 1 Dec 1999.
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Bob, Bob and ALL,
Three O-320 Rebels now and you still couldn't get me to move the firewall!
Like Bob P. says everything gets moved back 3 inches except the cabin around
you! Radios no longer fit the panel(the original firewall position only
leaves 1/4" on a KLX135 comm/gps), the windshield will now overhang the
engine compartment, rudder pedals move back, thus you sit 3" further back,
stick no longer in comfortable spot if left on the carrythru, etc. etc. If
it comes out a little nose heavy, it just means that the more your throw in
the back, the better it flys and you don't have to worry about exceeding the
aft CofG.
To give you ideas of weights and balances:
Howard's O-320-E2D rebel with full gyro panel, 32lb McCauley prop etc
weighed out at 950lb( when unpainted and on wheels) and empty C of G 9.7" in
aft of datum. Battery located in tail in front of 3rd bulkhead back from
float point, fiberglass tail spring and Scott 3200 tailwheel.
My Rebel O-320-C2A (same as B1) with full gyro panel, warp drive prop, Gill
25 Battery (still) on the firewall lengthwise, alum. flaperons and 16lb of
counterbalance, 4 upholstered seats, wheel pants, 3 leaf steel tail spring
and Scott 3200 tailwheel just weighed in at 996 lb(painted), empty C of G
10.42" aft of datum.
Rebel I just rebuilt O-320-E2D, Full gyro panel, 40 lb Sensenich Propellor,
battery just behind float point bulkhead, fiberglass tail spring and Maule
tailwheel weighed out at 966lb (unpainted) and empty C of G 8.16" aft of
datum.
All 3 aircraft when piloted and fueled, fit pretty much into Murphy's new
preferred operating C of G (the very forward part of it anyway)
The closest 2, to compare, are Howards and the rebuild as they only weighed
out 16 lbs different and the first obvious difference is 8 lbs for the
propellors. Next is the tailwheel, Maule about 3 lbs lighter than the Scott.
This puts them within 5 lbs of each other but C of G 1.6" different. If I
moved the Battery back to the matching location as Howards this would make
them almost identical. And yes, you can really feel the difference flying
the Rebuild at low fuel weights compared to flying mine with the 10.42 empty
C of G. Stalls quicker and less elevator authority(I can still land it
tailwheel first though), but nothing that is going to take you by surprise.
This Nose Heavy C of G is easy to get rid of by loading your aircraft
baggage compartment with all the stuff you need to survive at Oshkosh for a
week(or your winter survival kit and snowshoes this time of year(I know you
don't get snow in California)) or simply putting the Battery further back,
putting a steel tail spring and heavy tailwheel on. Every 5 lbs at the tail
spring area will move the empty C of G back approximately 1". If I removed
30 lbs from the nose, by putting a Warp Drive Prop on, this aircrafts C of G
would be absolutely perfect.(but I really prefer the performance of this new
74X56 Sensenich Prop!)
I can't make the decision for you, I can only offer past experiences and
knowledge! By the way, anyone telling you that their O-320 Rebel weighs less
than 900lbs even with a sparse panel and bare interior, weighed their plane
on "broken" scales so they could "legally" carry the extra weight they know
it can!(or left some parts out of the plane)
By the way the tail spring I mentioned(since there has been a lot of talk
about them), is available at CANADIAN TIRE! 3 leaf utility trailer spring, 1
3/4" wide(just like we need), approx. $32, cut the curls off both ends,
double spring area bolted to tailwheel. 3rd reinforcing leaf area centered
between wheel and post, double spring area under post clamps(same thickness
as original aluminum one) and single leaf area bolted to tail cone attach
bracket. Adjust tail wheel trailing angle to liking with spacer at attach
bolt. (I haven't managed to make this steel one go up through my rudder yet,
but I did it with both the aluminum one and the fiberglass one)
Anyone tired of my babbling yet? My Wife wants me to get some work done
around here, so see you later!
Blue skies, Wayne
P.S. I only went to 150 HP because I was tired of getting stuck in wet snow
on wheel penetration skis.(but I can sure get used to this 2100FPM climb(at
1350lbs) on wheels) A 118HP O-235 would be just fine if you are only
planning to fly wheels. If you change your mind later and switch to an
O-320, by then there will be a market for all of our old O-235's as the kit
industry has realized there is now a surplus of them and are building kits
such as the RV-9 to use these lower powered engines!
-----Original Message-----
From: Bob Patterson <
bob.patterson@canrem.com>
To: Murphy Rebel Builders List <
murphy-rebel@dcsol.com>
Date: Wednesday, December 01, 1999 7:04 PM
Subject: Re: Rebel "652" Wing tanks
Let's back up a bit .... Are you absolutely sure you want to use the
O-320 ?? Why ??? You really have to think about the kind of flying
you will be doing - and how much all that fuel will cost over the next
20 or 30 years ! ;-) The upgrade can always be done later, although
it IS a big job - it starts at the front of the door posts ! There
are at least 3 Rebels here that have flown happily for years, with
O-235's, then been upgraded.
I'm already on record as not liking the O-320 Rebel from a pilot
position - it moves you back 3", your feet, your seat, and your EYES !!
The visibility and overall feel of flying the aircraft is COMPLETELY
different ! <I> like sitting up front, with lots of sky visible -
old glider pilot thing ! :-) If you've never flown anything else, it
likely isn't a problem ... the Rebel is still "The Best floatplane in the
world !" (TM) :-) You will find that you will NEED to install at
least the overhead skylights, so you can see out in turns ! With the
standard firewall position, the windshield and the small oval skylights
are enough for a good lookout... the extras are really nice, though.
The Rebels that didn't have the firewall moved were very early ones,
before the factory had done the mods. themselves. If the C of G is very
far forward, you do not get the same feel or performance from the aircraft.
It will be harder to land well, and cruise will definitely be slower...
If the CofG is moved back, you still have the extra load on the mounts,
firewall, and fuse sides - although the floatfix mods & the firewall
beefups should help considerably with that ...
Keith Kinden did the first O-320, not moved - are you here, Keith ???
Any helpful comments ???
.....bobp
-----------------------------orig.-----------------------------------------
--
At 12:43 PM 12/1/99 -0500, you wrote:
Thanks Guys for all the replies. This really just convinced me to go with
my gut feeling and stick with the original designed "wet wing". I hope that
this is just the description and not the result-Ha! ha!. One more question
and that is in regarding firewall placement with the "O320". I will gladly
build it the suggested (3" back) as the instructions indicate, but I know
there are Rebels out there at the original position supporting this power
plant-What are your thoughts-(I'm probably about 4/6 weeks from starting
the fuselage)-Thanks again-Bob
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=text/html;charset=iso-8859-1 http-equiv=Content-Type>
<META content='"MSHTML 4.72.3110.7"' name=GENERATOR>
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<BODY bgColor=#ffffff>
<DIV><FONT color=#000000 size=2>Thanks Guys for all the replies. This
really
just convinced me to go with my gut feeling and stick with the original
designed
"wet wing". I hope that this is just the description and not the
result-Ha! ha!. One more question and that is in regarding firewall
placement
with the "O320". I will gladly build it the suggested (3"
back)
as the instructions indicate, but I know there are Rebels out there
at the
original position supporting this power plant-What are your thoughts-(I'm
probably about 4/6 weeks from starting the fuselage)-Thanks
again-Bob</FONT></DIV></BODY></HTML>
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