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----- Original Message -----
From: Angus McKenzie
To: rebel-builder@dcsol.com
Sent: Wednesday, August 04, 2004 7:39 PM
Subject: Fw: Prop for amphibs



----- Original Message -----
From: Angus McKenzie
To: murphy-rebel@dcsol.com
Sent: Wednesday, August 04, 2004 10:49 AM
Subject: Prop for amphibs


Hello all,
I know this subject has been beaten "ad nauseum" but I need to hear from
some amphib flyers with two bladed props on 0-320's. What is the
preferred pitch? I am running a McCauley 74-56 ,am unable to get more
than 2500rpm in level flight,full throttle (was 2750 on 8:50 tyres).Oil
temp is 225f.
I have borrowed a Sensenich 74-52 (from a PA-12 that switched to a
Borer) to try and am moving my oil cooler inlet port for the third
time.The inlet locations I have tried are,3"scat off the right rear
baffle,3" scat off the lower right nose-bowl (like our Pawnee),and
today,3"scat with a deflector off the right front baffle just inboard of
the nose-bowl opening (ala C-172).
All comments are welcome.This has become a frustrating issue for me as I
do not wish to over-heat or damage this engine that cost me $2!,!!!
dollars to build up.I have heard some builders run higher temps but my
friends in the engine business advised against extended running over
200f.
A crop dusting friend said on their PA-18's they had run a second
oil-cooler slung under the fire-wall,this may be my next plan.I saw
Brian Reed's Rebel at Brampton had a belly mounted cooler.
Anyway,I'm off to the shop to make a mess..................Angus



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Hi Angus
I could never get my temps down running cooling air through a scat tube.
Once I mounted the cooler on the rear of the right baffle "a la" cherokee
my temps are down in the 170-180 degree range. Come on over and take a look
if ya want.
Drew

At 07:45 PM 8/4/2004 -0400, you wrote:

----- Original Message -----
From: Angus McKenzie
To: rebel-builder@dcsol.com
Sent: Wednesday, August 04, 2004 7:39 PM
Subject: Fw: Prop for amphibs



----- Original Message -----
From: Angus McKenzie
To: murphy-rebel@dcsol.com
Sent: Wednesday, August 04, 2004 10:49 AM
Subject: Prop for amphibs


Hello all,
I know this subject has been beaten "ad nauseum" but I need to hear from
some amphib flyers with two bladed props on 0-320's. What is the
preferred pitch? I am running a McCauley 74-56 ,am unable to get more
than 2500rpm in level flight,full throttle (was 2750 on 8:50 tyres).Oil
temp is 225f.
I have borrowed a Sensenich 74-52 (from a PA-12 that switched to a
Borer) to try and am moving my oil cooler inlet port for the third
time.The inlet locations I have tried are,3"scat off the right rear
baffle,3" scat off the lower right nose-bowl (like our Pawnee),and
today,3"scat with a deflector off the right front baffle just inboard of
the nose-bowl opening (ala C-172).
All comments are welcome.This has become a frustrating issue for me as I
do not wish to over-heat or damage this engine that cost me $2!,!!!
dollars to build up.I have heard some builders run higher temps but my
friends in the engine business advised against extended running over
200f.
A crop dusting friend said on their PA-18's they had run a second
oil-cooler slung under the fire-wall,this may be my next plan.I saw
Brian Reed's Rebel at Brampton had a belly mounted cooler.
Anyway,I'm off to the shop to make a mess..................Angus



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Drew





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I am also fighting oil temps in excess of 225 using 3 inch scat off the left
rear baffle and cooler (new) on the firewall. I will look for room to mount
the cooler directly on the right rear baffle.
Jerald




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Hi Angus. I use the 74-54 Sensenich with my 150 hp 0320 Rebel
amphib. Seems to be just right. I get 2500 on take-off, 2560 on
climb and about 2720 straight and level.

I used to have cooling problems with my CHT's, but no more. I
enlarged my inlets, and in the hottest weather, 35+C, my hottest
cyl is around 380 in cruise, and the hottest it ever gets in
climb is about 420. I never did have a problem with oil cooling
and even now in the hottest weather still have about an inch and
half taped off. Mine is mounted at the rear of the right baffle.
I believe some people have gone to 4 inch scat hoses for those
with firewall mounted coolers.

Hope you get it solved soon. Good luck.

Walter

-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of
Angus McKenzie
Sent: Wednesday, August 04, 2004 4:45 PM
To: rebel-builders@dcsol.com
Subject: Fw: Prop for amphibs



----- Original Message -----
From: Angus McKenzie
To: rebel-builder@dcsol.com
Sent: Wednesday, August 04, 2004 7:39 PM
Subject: Fw: Prop for amphibs



----- Original Message -----
From: Angus McKenzie
To: murphy-rebel@dcsol.com
Sent: Wednesday, August 04, 2004 10:49 AM
Subject: Prop for amphibs


Hello all,
I know this subject has been beaten "ad nauseum" but I
need to hear from
some amphib flyers with two bladed props on 0-320's.
What is the
preferred pitch? I am running a McCauley 74-56 ,am
unable to get more
than 2500rpm in level flight,full throttle (was 2750
on 8:50 tyres).Oil
temp is 225f.
I have borrowed a Sensenich 74-52 (from a PA-12 that
switched to a
Borer) to try and am moving my oil cooler inlet port
for the third
time.The inlet locations I have tried are,3"scat off
the right rear
baffle,3" scat off the lower right nose-bowl (like our
Pawnee),and
today,3"scat with a deflector off the right front
baffle just inboard of
the nose-bowl opening (ala C-172).
All comments are welcome.This has become a frustrating
issue for me as I
do not wish to over-heat or damage this engine that
cost me $2!,!!!
dollars to build up.I have heard some builders run
higher temps but my
friends in the engine business advised against
extended running over
200f.
A crop dusting friend said on their PA-18's they had
run a second
oil-cooler slung under the fire-wall,this may be my
next plan.I saw
Brian Reed's Rebel at Brampton had a belly mounted cooler.
Anyway,I'm off to the shop to make a
mess..................Angus



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Hi Angus

I have an 0320 150 HP with a Sensenich 74x56. I would like to re-pitch it to
a 54 like Walter's. We flew comparisons a few weeks ago and he was not really
any slower than I was in cruise but was better for climb/take off. I think
74x54 is a good combination. Of course it all depends on what you want. A borer
will get you off and up in a hurry but you won't go very fast.

At one point in climb out from 800 Mile House, on a hot day, I had trouble
getting over 7000' as if the plane just wouldn't climb any more. CHT was 450 F
(I don't have enlarged inlets like Walter and I would recommend those who are
still building to enlarge them) and I backed off to cool down. Walter just kept
climbing like a rocket. I was not a happy camper.

My oil cooler is on the fire wall and a 4" scat tube off the left rear baffle
and my oil temps in hot summer weather are 190-200 F.

Bruce




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At 08:17 PM 8/4/2004 -0400, you wrote:

Hi Angus
I could never get my temps down running cooling air through a scat tube.
Once I mounted the cooler on the rear of the right baffle "a la" cherokee
my temps are down in the 170-180 degree range. Come on over and take a look
if ya want.
Drew

Oops my bad. that should be the left baffle. Pilots side.

Drew





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Hi Jerald !

Before relocating the cooler - - some builders have had
good results by mounting it on the firewall with the air flow
parallel to the firewall, and angled down, so the hot air can exit
out the bottom of the cowl opening. This seems much better than having
the hot air blasting straight through onto the firewall !

Mine is set up that way, and it works pretty well. Just a thought ....

.....bobp

-----------------------------orig.-----------------------------
At 09:23 PM 8/4/04 EDT, you wrote:

I am also fighting oil temps in excess of 225 using 3 inch scat off the left
rear baffle and cooler (new) on the firewall. I will look for room to mount
the cooler directly on the right rear baffle.
Jerald




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Hi Angus,
I can give my .02 on the oil cooler problem, but when it comes to the right prop, I like to know your final decision.
Any way I have also fought the oil temp problem. Not bad, just to high on extended climbs or hot days and multiple lake ops. I have a firewall mounted right side 3" scat tube from the baffling at the rear of the engine.
The efforts I've made started with making sure the scat tube to top of the oil cooler was well sealed. no leaks around the edges. I then tried a bilge blower that was nice and light and explosion proof and 3" dia. easy fit. Results? great temps on the water but even with the fan running in flight I think the fan blocked the tube far more thatn it helped. Scrap that idea. I opened the cowl even more below the cooler. That was worth about 5 deg. I then began talking with a friend who has a Defiant(Rutan push me pull you) with cooler problems, and he had done metered tests for pressures before and after the cooler but his efforts lead me to look at airflow more. I the had a chance to look at a RV 6 and noted he had a piece of baffling that went behind the spinner that stopped the inlet air from turbulating behind the spinner area. Not to tuff to do so I gave it a whirl. Just before OSH we finally had a 90f+ day so I went for a ride, did a 70mph climb for 15 min, oil temp never went over
215f and when I levele
d
out it only took about another 10 min for the temps to go back to the 190f. The long climb out of OSH to go high over the lake coming home was a cooler day but my temps were inline the whole time. As of now I'm satisfied. The last thing I was going to do was to create a box around oil cooler outlet to get the outflow closer to the bottom of the cowl. I still think that area on the firewall is a dead area for airflow but I'm good for now. Ok that's my .02 Goodluck, Curt N97mr



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G'day Angus ;

When we originally built our Rebel , we fitted an 0-235 / 130
horsepower version .... we had constant ongoing problems with high
cylinder head temperatures and high oil temperatures.

(230

Thank you to everyone who replied to my post about props and oil temps on
amphibs.

Yesterday I relocated the oil cooler air intake to the left front
baffle,also put a 3.5" scoop behind it.Revised my water-rudder cockpit
control and installed a Sensenich 74-52 a friend took off his PA-12.Bob and
Anna Patterson kindly took my McCauley 74-56 prop back to Leavens in Toronto
with them of Thursday and saved me making the drive.After I fly the 52" prop
tomorrow I will call Leavens and tell them what twist I want on my
prop.George said a repitch was $90 CDN, he also told me that over the life
of a Sensenich prop you are only allowed a total of 9"s of repitch, McCauley
has no restriction.I would like to move the cooler to the rear baffle but
that will require some more engineering to complete,another winter project.

While I am talking about props I should mention that I have a Warp 3
blade,70",nickel leading edges,about 160TT from my old Lycoming 0-290 I
would like to either sell or trade toward a 74" aluminium 2 blade so I will
have a separate prop for wheels or floats.

When I get home from work at the fire station tomorrow morning my wife and I
plan to fly to the tip of Long Point,in Lake Erie for a picnic and hike and
perhaps later down the shore to Pelee Is. to joint the other members of our
St.Thomas COPA chapter for a fly in fish supper.By the time I get home
tomorrow night I should have a better idea about prop pitches.

I should also mentioned that bobp picked up his beautiful freshly yellow and
red painted Rebel this week.It has a new cowl with a Thorpe T-18 nose bowl
and really neat exit ducting.Bob took lots of pictures before any bugs got
smashed on it so maybe he could post one to the web-site.

Best regards to all, Angus




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hi angus i`m running a 74 x 56 Sensenich 2550 on climb out
2700-2725 wide open 124 mph but it`s a 160 hp E2D

oil can run up too 220 on a real hot day but normally about 208 that
oil i`m using is good for 268 it says in the literature so I feel we still
have a good margin of safety cht is almost never over 325 deg f

how would a borer 82 x 43 work on that plane? i can borrow one for a while
if i want to. is it worth it?

bob fisher rebel 342 amphib parry sound ontario



----- Original Message -----
From: "Angus McKenzie" <angus@lweb.net>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, August 04, 2004 7:45 PM
Subject: Fw: Prop for amphibs

----- Original Message -----
From: Angus McKenzie
To: rebel-builder@dcsol.com
Sent: Wednesday, August 04, 2004 7:39 PM
Subject: Fw: Prop for amphibs



----- Original Message -----
From: Angus McKenzie
To: murphy-rebel@dcsol.com
Sent: Wednesday, August 04, 2004 10:49 AM
Subject: Prop for amphibs


Hello all,
I know this subject has been beaten "ad nauseum" but I need to hear from
some amphib flyers with two bladed props on 0-320's. What is the
preferred pitch? I am running a McCauley 74-56 ,am unable to get more
than 2500rpm in level flight,full throttle (was 2750 on 8:50 tyres).Oil
temp is 225f.
I have borrowed a Sensenich 74-52 (from a PA-12 that switched to a
Borer) to try and am moving my oil cooler inlet port for the third
time.The inlet locations I have tried are,3"scat off the right rear
baffle,3" scat off the lower right nose-bowl (like our Pawnee),and
today,3"scat with a deflector off the right front baffle just inboard of
the nose-bowl opening (ala C-172).
All comments are welcome.This has become a frustrating issue for me as I
do not wish to over-heat or damage this engine that cost me $2!,!!!
dollars to build up.I have heard some builders run higher temps but my
friends in the engine business advised against extended running over
200f.
A crop dusting friend said on their PA-18's they had run a second
oil-cooler slung under the fire-wall,this may be my next plan.I saw
Brian Reed's Rebel at Brampton had a belly mounted cooler.
Anyway,I'm off to the shop to make a mess..................Angus



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-----------------------------------------------------

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