Weight and Balance

Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 9:21 pm

I thought some of you guys might be interested in these calculations for
weight and balance. Because what I have been told by MAM, I was concerned
with my weight and balance for I never cut back the firewall on a standard
Rebel with an 0320. So I weighed my plane today, minus prop and battery, and
used calculations to check different locations for the battery with
combinations for wood and metal props.

I calculated a metal prop at 38 lb. and a wood prop at 10 lb. The battery and
box at 24 lb. MAM's recommendation for most forward is 10.85 and most aft is
18.10. Here were the best locations;

With a metal prop and the battery located in the middle of first bulkhead,
aft of the baggage compartment, the empty C&G was 8.38. The most forward
loaded C&G problem was 10.70 and the most aft loaded problem was 17.66.

With a metal prop and the battery located in the middle of the first bulkhead
forward of the elevator pulleys (way back in the tail), the empty C&G was
8.88. The most forward loaded C&G problem was 11.09 and the most aft loaded
at 17.90

With a wood prop and the battery located on the firewall, the empty C&G was
7.71. The most forward loaded C&G problem was 10.22 and the most aft loaded
problem 17.42.

I believe the best combination was the metal prop and to locate the battery
in the middle of the first bulkhead aft of the baggage compartment where it
is more accessible without climbing inside the fuselage. With some survival
gear and a few tools behind the seat this should work out real good.

The empty weight was 936 lb. The plane is unpainted so I'm guessing it will
put on 25 more lb. with most of it aft of the Datum. This will push the empty
C&G back even a bit more.

Blue skies and tailwinds
Bruce G

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scott.hibbs · Post by **scott.hibbs** » Fri Feb 17, 2012 9:21 pm

Bruce, I have been looking at the same thing (although my rebel is far from
finished). It looks like you are pretty close with the wood prop and the
battery on the firewall. Will the paint be enough to get you up to 10.85?
Can you tell me what the forward CG assumptions were? I am trying to find a
way to keep the battery up front (need room for my kayak in the back).

Scott
hibbs@pacifier.com

-> With a wood prop and the battery located on the firewall, the empty C&G was
-> 7.71. The most forward loaded C&G problem was 10.22 and the most aft loaded
-> problem 17.42.
->
->
-> I believe the best combination was the metal prop and to locate the battery
-> in the middle of the first bulkhead aft of the baggage compartment where it
-> is more accessible without climbing inside the fuselage. With some survival
-> gear and a few tools behind the seat this should work out real good.
->
-> The empty weight was 936 lb. The plane is unpainted so I'm guessing it will
-> put on 25 more lb. with most of it aft of the Datum. This will push the
empty
-> C&G back even a bit more.
->
-> Blue skies and tailwinds
-> Bruce G

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Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 9:21 pm

Hi Scott,

If it were me, and you want to keep your battery on the firewall and you
haven't cut the firewall back, I would stick with a light prop like a wood
Sensenich. Warp Drive and IVO will not sell to Lycoming any more because of
cracking problems.

I figure the paint may weigh 25 or 30 lb.? And most of it is behind the
leading edge of the wing (datum), so that will help move the C&G back some.

Bob P says he flies with a metal prop and battery on the firewall and the
Rebel flies fine. Your Kayak will move the C&G back for loading too.

Bruce G

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Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Fri Feb 17, 2012 9:21 pm

Hi Bruce!

Two things!

Is it true that Warp Drive will not sell for Lycoming applications anymore??
I just did my annual on the old personal Rebel yesterday, with another year
gone (and a pathetic 23.9 hours more on it) and it still looks as good as
last year mounted on my 150 HP x O-320. BUT remember I have that odd ball
70" x 3 blade, as opposed to everyone that is having delaminating/cracking
problems 72" ones! Harmonics??

The other thing to correct in your e-mail below is that Bob p's Rebel
battery is mounted just behind the float attach bulkhead in the tail cone,
not on the firewall!

Take care,
Wayne G. O'Shea
www.irishfield.on.ca

----- Original Message -----
From: <Legeorgen@cs.com>
To: <murphy-rebel@dcsol.com>
Sent: Saturday, November 03, 2001 10:54 AM
Subject: Re: Weight and Balance

Hi Scott,

If it were me, and you want to keep your battery on the firewall and you
haven't cut the firewall back, I would stick with a light prop like a wood
Sensenich. Warp Drive and IVO will not sell to Lycoming any more because

of

cracking problems.

I figure the paint may weigh 25 or 30 lb.? And most of it is behind the
leading edge of the wing (datum), so that will help move the C&G back

some.

Bob P says he flies with a metal prop and battery on the firewall and the
Rebel flies fine. Your Kayak will move the C&G back for loading too.

Bruce G

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Walter Klatt · Post by **Walter Klatt** » Fri Feb 17, 2012 9:21 pm

Some time ago on this list there was discussion about lighter batteries for
the Rebel. One that was recommended was the Odyssey PC625, which has a CCA
of 265, but only weighs 13.2 pounds.

Currently, I have a 25 pound Concorde battery mounted forward of the
firewall with the O320 and the 12 pound Warp Drive prop. My firewall is cut
back 3 inches and the c of g comes in at 8.93 empty. I also have about 20
pounds of survival gear and the ELT stuffed back into my tail which brings
my c of g back to a more pleasant 10.7 empty.

-----Original Message-----
From: murphy-rebel@dcsol.com [mailto:murphy-rebel@dcsol.com]On Behalf Of
Legeorgen@cs.com
Sent: November 3, 2001 7:55 AM
To: murphy-rebel@dcsol.com
Subject: Re: Weight and Balance

Hi Scott,

If it were me, and you want to keep your battery on the firewall and you
haven't cut the firewall back, I would stick with a light prop
like a wood
Sensenich. Warp Drive and IVO will not sell to Lycoming any more
because of
cracking problems.

I figure the paint may weigh 25 or 30 lb.? And most of it is behind the
leading edge of the wing (datum), so that will help move the C&G
back some.

Bob P says he flies with a metal prop and battery on the firewall and the
Rebel flies fine. Your Kayak will move the C&G back for loading too.

Bruce G

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Bob Patterson · Post by **Bob Patterson** » Fri Feb 17, 2012 9:21 pm

Hi Bruce !

Actually, my battery is just behind the baggage area, but,
with the Sensenich metal prop, the empty CG is at 8.1" - flies great !
You're right - paint always moved the CG back - as well as adding
25 to 75 lb (!) ......

Scott could use one of the newer batteries that are only about
3" X 11" - <that> could mount behind the baggage area, on the right side
lip, between the bulkheads, leaving the floor area open for sleeping
or the kayak.

....bobp
------------------------------orig.--------------------------------------
At 10:54 AM 11/3/01 EST, you wrote:

Hi Scott,

If it were me, and you want to keep your battery on the firewall and you
haven't cut the firewall back, I would stick with a light prop like a wood
Sensenich. Warp Drive and IVO will not sell to Lycoming any more because of
cracking problems.

I figure the paint may weigh 25 or 30 lb.? And most of it is behind the
leading edge of the wing (datum), so that will help move the C&G back some.

Bob P says he flies with a metal prop and battery on the firewall and the
Rebel flies fine. Your Kayak will move the C&G back for loading too.

Bruce G

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Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 9:21 pm

Hi Wayne,

Thanks for the correction about Bob's battery location. I wasn't aware of
that.

Bruce G

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Mike Kimball · Post by **Mike Kimball** » Fri Feb 17, 2012 9:21 pm

Hey! What a great idea! I can deal with my overweight Chevy in the front
by using 10 or 20 coats of paint in the last five feet or so of my tailcone.
Should fill those annoying minor screw ups too! Maybe I can use enough
paint to completely hide the rivet heads. Hmmm...

Mike Kimball
SR#044

-----Original Message-----
From: murphy-rebel@dcsol.com [mailto:murphy-rebel@dcsol.com]On Behalf Of
Bob Patterson
Sent: Saturday, November 03, 2001 12:10 PM
To: murphy-rebel@dcsol.com
Subject: Re: Weight and Balance

Hi Bruce !

Actually, my battery is just behind the baggage area, but,
with the Sensenich metal prop, the empty CG is at 8.1" - flies great !
You're right - paint always moved the CG back - as well as adding
25 to 75 lb (!) ......

Scott could use one of the newer batteries that are only about
3" X 11" - <that> could mount behind the baggage area, on the right side
lip, between the bulkheads, leaving the floor area open for sleeping
or the kayak.

....bobp
------------------------------orig.--------------------------------------
At 10:54 AM 11/3/01 EST, you wrote:

Hi Scott,

If it were me, and you want to keep your battery on the firewall and you
haven't cut the firewall back, I would stick with a light prop like a wood
Sensenich. Warp Drive and IVO will not sell to Lycoming any more because of
cracking problems.

I figure the paint may weigh 25 or 30 lb.? And most of it is behind the
leading edge of the wing (datum), so that will help move the C&G back some.

Bob P says he flies with a metal prop and battery on the firewall and the
Rebel flies fine. Your Kayak will move the C&G back for loading too.

Bruce G

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Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 9:21 pm

Hey Mike,

Buy a one gallon can of bond, that will fix those rivet heads. It's cheaper
than paint!

Bruce G

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Rebflyer · Post by **Rebflyer** » Fri Feb 17, 2012 9:21 pm

Hi Bruce and Scott,
The difference between no paint and paint on my Rebel was 26 lbs of paint and 9lbs of that was on the tailwheel. I think that may be a little lighter than some on the paint, I have heard as much as 50lbs.
If either of you happen to think of it, when you are doing the actual W&B if you could put a level on the bottom of the wing, and tell me what that angle is I'M just a little curious. Either digitaly or the mesurement on a 4' level. Thanks Curt N97MR

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Rebflyer · Post by **Rebflyer** » Fri Feb 17, 2012 9:21 pm

Hi Bruce and Scott,
The difference between no paint and paint on my Rebel was 26 lbs of paint and 9lbs of that was on the tailwheel. I think that may be a little lighter than some on the paint, I have heard as much as 50lbs.
If either of you happen to think of it, when you are doing the actual W&B if you could put a level on the bottom of the wing, and tell me what that angle is I'M just a little curious. Either digitaly or the mesurement on a 4' level. Thanks Curt N97MR

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Rebflyer · Post by **Rebflyer** » Fri Feb 17, 2012 9:21 pm

Hi Bruce and Scott,
The difference between no paint and paint on my Rebel was 26 lbs of paint and 9lbs of that was on the tailwheel. I think that may be a little lighter than some on the paint, I have heard as much as 50lbs.
If either of you happen to think of it, when you are doing the actual W&B if you could put a level on the bottom of the wing, and tell me what that angle is I'M just a little curious. Either digitaly or the mesurement on a 4' level. Thanks Curt N97MR

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Legeorgen · Post by **Legeorgen** » Fri Feb 17, 2012 9:22 pm

Hi Curt,

9 lb. on the tail from painting your plane sounds great. I wouldn't have
suspected it would have added that much to the tail weight. That will help my
weight and balance.

My wings were very close to level but I didn't check it when the plane was
plumed. You could take a measure from the bottom of the fuselage, or door
sill, both front and back, up to the bottom of the wing. This would
affectively give you the wing angle of attack at level cruse.

Bruce G

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scott.hibbs · Post by **scott.hibbs** » Fri Feb 17, 2012 9:22 pm

Thanks for the info Curt. My Rebel is still a ways from being done, but when
it is, I'll post here and note the angle.

Scott

On 11/7/2001 9:03 PM, REBFLYER@AOL.COM wrote to MURPHY-REBEL:

-> Hi Bruce and Scott,
-> The difference between no paint and paint on my Rebel was 26 lbs of paint
and 9lbs of that was on the tailwheel. I think that may be a little lighter
than some on the paint, I have heard as much as 50lbs.
-> If either of you happen to think of it, when you are doing the actual W&B
if you could put a level on the bottom of the wing, and tell me what that
angle is I'M just a little curious. Either digitaly or the mesurement on a 4'
level. Thanks Curt N97MR

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Walter Klatt · Post by **Walter Klatt** » Fri Feb 17, 2012 9:22 pm

Curt, not sure if you got an answer to this yet. I did some measurements on
my plane today and came up with the following.

The bottom of the wing is slightly convex, so took the readings between the
2nd and 3rd row of rivets from the rear spar. The angle of incidence was
about 1 degree from straight and level, maybe 1.25. It was hard to get an
absolutely accurate reading of the fuse and wings with my level.

If either of you happen to think of it, when you are doing the
actual W&B if you could put a level on the bottom of the wing,
and tell me what that angle is I'M just a little curious. Either
digitaly or the mesurement on a 4' level. Thanks Curt N97MR

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