Today's Message Index:
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1. 11:42 AM - Re: Zenair601HDS Stratus/Ram cooling problem (Ronbo135@aol.com)
2. 11:43 AM - Re: Zenair601HDS Stratus/Ram cooling problem (Ronbo135@aol.com)
3. 11:57 AM - Re: Zenair601HDS Stratus/Ram cooling problem (Hinde, Frank George (Corvallis))
4. 12:35 PM - Re: Zenair601HDS Stratus/Ram cooling problem (Bryan Martin)
Message 1
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| Subject: | Re: Zenair601HDS Stratus/Ram cooling problem |
In a message dated 6/28/2011 2:43:27 P.M. Pacific Daylight Time,
tshankland@sbcglobal.net writes:
Ron,
I fly A 601HD with a status Suburu. My engine temperature runs at 190 with
an occasional 200 on long hot climbouts. I think that a lot of the
problems builders have had with this engine is due to high temperatures. I spent
1
year designing my cooling system and gave a couple of seminars at OSH
about cooling systems design. I don't know if that stock design can ever give
really good results.My system looks somewhat "radical" and is not easily
adapted to a finished aircraft. The problem is that the stock system has no
ducting of pressure recover, plus the fact that exhaust and engine heat go
into the radiator. Various idea expressed in this forum can help, but the
root cause is an inadequate design
Tim Shankland
----- Original Message -----
From: _ron hansen_ (mailto:ronhansen123@gmail.com)
Sent: Monday, June 27, 2011 3:53 PM
Subject: Stratus-List: Zenair601HDS Stratus/Ram cooling problem
Hi listers,
I've been quiet a long time due to life interfering with my plans, but I
need some help. I had about 60 hours on my 601HDS with a Stratus on it. I
was fighting temp. issues from the start, adjusting the carb jets and such.
I had Ram modify the heads before it flew. Anyway, I never went past the
Stratus 230 deg. "water temp" redline, but often approached it. Taxiing
in after 60 flight hours I broke a valve seat and later learned broke a
piston. I have not been pleased with Stratus support for years so I had Ram
Performance rebuild the engine. He also made some other changes and it now
runs stronger and cooler, but still not cool enough. I moved the "water
temp" probe from the Stratus setup in the cylinder head dry-hole to actual
water as it comes out of the engine. Ram says water temp redline should be
220 deg. and the engine should run at the thermostat setting of 190 deg.
Research I've done would indicate the same for long engine life.
Anyway, I still get water temp climbing to 220 a few minutes after takeoff
on a warm day and I suspect it would go higher. My radiator is the stock
Zenair radiator installed per plans. Gaps are sealed. Coolant is 50/50
per instructions. I'm beginning to think the Zenith setup is not suitable
for a 100HP engine that is water cooled. The Rotax they designed it for only
uses water to cool the heads.
I don't want to ruin my new Ram-rebuilt engine. It is running really
well: stronger, cooler, lower fuel burn......but it's not running at the temps
it should do to a weak cooling system. If anyone has data or ideas that
would help I would appreciate hearing from you. I recall all sorts of
discussion from years past (this plane took me many years to build from plans),
but I can't remember where all those ideas ended up. I know some were
abandoned, but others probably solved some or all of the problem. I've gone
through the archives, but you never know if you're missing something important
that came later.
Thanks,
Ron Hansen
Los Angeles
601HDS, Ram-Rebuilt (formerly Stratus) Subaru EA81
href="http://www.matronics.com/Navigator?Stratus-List">http://www.matronics.com/Navigator?Stratus-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 2
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| Subject: | Re: Zenair601HDS Stratus/Ram cooling problem |
Thanks, Tim.
Your conclusion that the design is inadequate is in line with what I'm
learning and hearing.
In a message dated 6/28/2011 2:43:27 P.M. Pacific Daylight Time,
tshankland@sbcglobal.net writes:
Ron,
I fly A 601HD with a status Suburu. My engine temperature runs at 190 with
an occasional 200 on long hot climbouts. I think that a lot of the
problems builders have had with this engine is due to high temperatures. I spent
1
year designing my cooling system and gave a couple of seminars at OSH
about cooling systems design. I don't know if that stock design can ever give
really good results.My system looks somewhat "radical" and is not easily
adapted to a finished aircraft. The problem is that the stock system has no
ducting of pressure recover, plus the fact that exhaust and engine heat go
into the radiator. Various idea expressed in this forum can help, but the
root cause is an inadequate design
Tim Shankland
----- Original Message -----
From: _ron hansen_ (mailto:ronhansen123@gmail.com)
Sent: Monday, June 27, 2011 3:53 PM
Subject: Stratus-List: Zenair601HDS Stratus/Ram cooling problem
Hi listers,
I've been quiet a long time due to life interfering with my plans, but I
need some help. I had about 60 hours on my 601HDS with a Stratus on it. I
was fighting temp. issues from the start, adjusting the carb jets and such.
I had Ram modify the heads before it flew. Anyway, I never went past the
Stratus 230 deg. "water temp" redline, but often approached it. Taxiing
in after 60 flight hours I broke a valve seat and later learned broke a
piston. I have not been pleased with Stratus support for years so I had Ram
Performance rebuild the engine. He also made some other changes and it now
runs stronger and cooler, but still not cool enough. I moved the "water
temp" probe from the Stratus setup in the cylinder head dry-hole to actual
water as it comes out of the engine. Ram says water temp redline should be
220 deg. and the engine should run at the thermostat setting of 190 deg.
Research I've done would indicate the same for long engine life.
Anyway, I still get water temp climbing to 220 a few minutes after takeoff
on a warm day and I suspect it would go higher. My radiator is the stock
Zenair radiator installed per plans. Gaps are sealed. Coolant is 50/50
per instructions. I'm beginning to think the Zenith setup is not suitable
for a 100HP engine that is water cooled. The Rotax they designed it for only
uses water to cool the heads.
I don't want to ruin my new Ram-rebuilt engine. It is running really
well: stronger, cooler, lower fuel burn......but it's not running at the temps
it should do to a weak cooling system. If anyone has data or ideas that
would help I would appreciate hearing from you. I recall all sorts of
discussion from years past (this plane took me many years to build from plans),
but I can't remember where all those ideas ended up. I know some were
abandoned, but others probably solved some or all of the problem. I've gone
through the archives, but you never know if you're missing something important
that came later.
Thanks,
Ron Hansen
Los Angeles
601HDS, Ram-Rebuilt (formerly Stratus) Subaru EA81
href="http://www.matronics.com/Navigator?Stratus-List">http://www.matronics.com/Navigator?Stratus-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 3
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| Subject: | Zenair601HDS Stratus/Ram cooling problem |
I think its more like no design at all. I hear all the time about how a wat
er cooled system CAN be better than air cooled. I mean look at the Mustang!
The fact of the matter is, its really never been done.
If its any consolation the faster the airplane the harder it appears to mak
e it work. RV's running water cooled motors almost always run 20 to 25 knot
s slower than their air-cooled counterparts for the same fuel burn.
As for me my RV7a has an IO360 (Lycoming) but I did build a variation of my
Zodiac wing root electric fuel pump system..I.e junked the mechanical fuel
pump...Just to upset the "proper airplane engine" establishment..:)
Frank
601HDS..Stratus with ram heads
RV7a Io360
Cell/Mobile +1 541 602 8756
Tel +1 541 715 7568
From: owner-stratus-list-server@matronics.com [mailto:owner-stratus-list-se
rver@matronics.com] On Behalf Of Ronbo135@aol.com
Sent: Wednesday, June 29, 2011 11:42 AM
Subject: Re: Stratus-List: Zenair601HDS Stratus/Ram cooling problem
Thanks, Tim.
Your conclusion that the design is inadequate is in line with what I'm lear
ning and hearing.
Message 4
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| Subject: | Re: Zenair601HDS Stratus/Ram cooling problem |
The Mustang and the Spitfire were designed around water-cooled engines. Their cooling
systems were designed right into the airframe from the start. Both planes
had much lower cooling drag than other aircraft of the time with similar horsepower.
The best water cooling systems for aircraft have the radiators buried
either in the fuselage or wing roots with carefully designed ducts directing
airflow over them. The Mustang cooling system produced almost enough thrust to
overcome the cooling drag entirely. It's going to be very difficult to match
that when you have to fit a water cooling system on an airframe that wasn't really
designed for it.
To help the radiator cool the engine, one trick is to block the heated air from
the cowl from flowing into the radiator so it can get cooler ambient air flow.
I have a scoop on my radiator that extends ahead of the outlets from the cowl.
I never see a problem with high water temps although I do see high oil temps
on long climb-outs on hot days.
On Jun 29, 2011, at 2:54 PM, Hinde, Frank George (Corvallis) wrote:
> I think its more like no design at all. I hear all the time about how a water
cooled system CAN be better than air cooled. I mean look at the Mustang!
>
> The fact of the matter is, its really never been done.
>
> If its any consolation the faster the airplane the harder it appears to make
it work. RVs running water cooled motors almost always run 20 to 25 knots slower
than their air-cooled counterparts for the same fuel burn.
>
> As for me my RV7a has an IO360 (Lycoming) but I did build a variation of my Zodiac
wing root electric fuel pump system..I.e junked the mechanical fuel pumpJust
to upset the proper airplane engine establishment..:)
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus re-drive.
do not archive.
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