Today's Message Index:
----------------------
1. 09:16 AM - Re: water temp guage (paul wilson)
2. 10:36 AM - Re: water temp guage (Lowell Fitt)
3. 11:27 AM - (Off-Topic) Wildlife (Michel Verheughe)
4. 05:55 PM - Re: (Off-Topic) Wildlife (Tom Jones)
5. 07:04 PM - Re: water temp guage (Paul Franz - Merlin GT)
6. 07:56 PM - Wingtank.com tank install, ongoing (WurlyBird)
Message 1
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| Subject: | Re: water temp guage |
Correct Paul.
Both are the prudent way to go. Of course the Stat is a feature that
Rotax forgot, but is usually required unless one lives in the more
temperate clims. However I note that some builders use the shutters
on the radiator instead, which means a T gauge for coolant is even
more critical due manual control of the shutters. I don't think that
gauge should be engine mounted, but S/B in the coolant lines.
Paul W
============
At 11:13 PM 1/2/2010, Paul F wrote:
>On Sat, January 2, 2010 10:26 pm, CLEMWEHNER wrote:
> > We're getting near done on a KFIV-912.
> >
> > But, when I planned the panel a few years ago, I included a
> Westach quad gauge with
> > CHT, and also made a hole for a separate water temp guage.
>
>Good design choice. You won't regret that decision.
>
> > Now that I think about it,
> > why would I need both? Doesn't CHT equal water temp in an engine
> with water cooled
> > heads?
>
>In a word - no. I definitely would have both CHT and water temp gauges.
>
>If it were mine I would use water temp gauge also.
>
> > Am I missing something?
>
>The quad CHT is important if you want to run lean of peak because you know the
>temperatures in each cylinder head. However, without fuel injection
>you still might
>not elect to run lean of peak. But if the cylinders run close in
>temp, you definitely
>can get significant fuel savings running lean of peak in cruise.
>
>The water temperature gauge is an essential instrument too. It will
>let you know if
>you're exceeding that T-stat controlled temp or that your operating
>temperature is too
>low. The cyl head temp reading will be much higher than the water
>temperature since
>the sensor is generally placed against the head under a spark plug.
>CHT is also
>effected by power setting whereas T-stat controlled water
>temperature should remain
>constant at all power settings.
>
>
>--
>Paul A. Franz
Message 2
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| Subject: | Re: water temp guage |
I'm strugglin to understand this. It has always been my understanding that
temperatures relate to engine performance and longevity. I am personally
comfortable knowing my engine's temps. I need a bit of help understanding
how knowing the coolent temp in addition will help me protect my engine. I
flew lots of hours getting temp readings only from a cylinder head sensor
and an oil temp sensor. I have found that even then, both needles pretty
much follow each other during a warm up and flight and in the early days
were typically on the low side. That is where the small oil cooler and the
shutters came in. Then the same gauges showed the temps of the engine.
What am I missing? I could understand the need for numerous temp sensors
and gauges if the operation temperature ranges were critically narrow, but
when the ranges are over 50? I'd rather save the ounce or two.
I found the following at:
http://www.rotaxservice.com/rotax_tips/engine_instruments.htm
Cylinder Head Temperature (CHT)
We found that many pilots confuse this instrument with a coolant temperature
instrument, and sometimes label it as such. The probe to this instrument
actually measures the temperature of the metal in your cylinder head. It
allows you to monitor the proper operation of the liquid cooling system that
cools your cylinder heads yet it does not measure the actual temperature of
that liquid.
Coolant temperature
No provision for a coolant temperature probe is provided on Rotax 4-stroke
engines and for good reason: the Cylinder Head Temperature instrument offers
a better insight into the proper operation of the liquid cooling system and
may reveal problems, such as the formation of air bubbles, that a coolant
temperature instrument would not.
Lowell
----- Original Message -----
From: "paul wilson" <pwmac@sisna.com>
Sent: Monday, January 04, 2010 6:42 AM
Subject: Re: Kitfox-List: water temp guage
>
> Correct Paul.
> Both are the prudent way to go. Of course the Stat is a feature that Rotax
> forgot, but is usually required unless one lives in the more temperate
> clims. However I note that some builders use the shutters on the radiator
> instead, which means a T gauge for coolant is even more critical due
> manual control of the shutters. I don't think that gauge should be engine
> mounted, but S/B in the coolant lines.
> Paul W
> ============
> At 11:13 PM 1/2/2010, Paul F wrote:
>>On Sat, January 2, 2010 10:26 pm, CLEMWEHNER wrote:
>> > We're getting near done on a KFIV-912.
>> >
>> > But, when I planned the panel a few years ago, I included a
>> Westach quad gauge with
>> > CHT, and also made a hole for a separate water temp guage.
>>
>>Good design choice. You won't regret that decision.
>>
>> > Now that I think about it,
>> > why would I need both? Doesn't CHT equal water temp in an engine
>> with water cooled
>> > heads?
>>
>>In a word - no. I definitely would have both CHT and water temp gauges.
>>
>>If it were mine I would use water temp gauge also.
>>
>> > Am I missing something?
>>
>>The quad CHT is important if you want to run lean of peak because you know
>>the
>>temperatures in each cylinder head. However, without fuel injection you
>>still might
>>not elect to run lean of peak. But if the cylinders run close in temp, you
>>definitely
>>can get significant fuel savings running lean of peak in cruise.
>>
>>The water temperature gauge is an essential instrument too. It will let
>>you know if
>>you're exceeding that T-stat controlled temp or that your operating
>>temperature is too
>>low. The cyl head temp reading will be much higher than the water
>>temperature since
>>the sensor is generally placed against the head under a spark plug. CHT is
>>also
>>effected by power setting whereas T-stat controlled water temperature
>>should remain
>>constant at all power settings.
>>
>>
>>--
>>Paul A. Franz
>
>
>
Message 3
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| Subject: | (Off-Topic) Wildlife |
If you fly a Kitfox with a Jabiru engine and you write both names in Google Alerts,
you learn a lot about American mammals and Australian birds! :-)
Happy New Year everyone,
Michel Verheughe
Norway
Kitfox 3 - Jabiru 2200
Do not archive
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</b></font></pre></body></html>
Message 4
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| Subject: | Re: (Off-Topic) Wildlife |
Oh yes. I have found much interesting reading about that little "Kit Fox" creature
on google. I didn't know the jabber was a bird though. I always figured
it was some kind of kangaroo.
I went to work for a Ski Doo dealer in 1970. I remember the owner of the dealership
was very proud to state to any customer coming into the shop that Ski Doo
snowmobiles (Bombardier) was the only snowmobile manufacturer that owned the
company that built it's engines. Thats the fact I find occasionally when I google
Rotax...Bombardier bought Rotax in 1970.
--------
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=280146#280146
Message 5
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| Subject: | Re: water temp guage |
On Mon, January 4, 2010 9:59 am, Lowell Fitt wrote:
>
> I'm strugglin to understand this. It has always been my understanding that
> temperatures relate to engine performance and longevity. I am personally
> comfortable knowing my engine's temps. I need a bit of help understanding
> how knowing the coolent temp in addition will help me protect my engine. I
> flew lots of hours getting temp readings only from a cylinder head sensor
> and an oil temp sensor. I have found that even then, both needles pretty
> much follow each other during a warm up and flight and in the early days
> were typically on the low side. That is where the small oil cooler and the
> shutters came in. Then the same gauges showed the temps of the engine.
> What am I missing? I could understand the need for numerous temp sensors
> and gauges if the operation temperature ranges were critically narrow, but
> when the ranges are over 50? I'd rather save the ounce or two.
I didn't realize there is no T-stat to regulate coolant temperature. In that case,
I'd
expect coolant temperature to track power setting and because of capacity design,
coolant temperatures will be often lower than ideal. Here's what I mean,
thermodynamically speaking. The compression of an ideal gas follows:
PV**n = C P is pressure, V is volume and C is a constant.
For the two extremes of compression for air, adiabatic and constant temperature
compression, n = 1.41 (adiabatic) and n = 1.0 for isothermal compression. Adiabatic
compression occurs when there is no heat transfer to the surroundings and isothermal
compression is where all the heat of compression is transferred to the surroundings.
We would like to have the highest possible thermal efficiency of the engine which
would ideally be with adiabatic compression. This would be the condition with the
highest possible coolant water temperature (closest to adiabatic) and hence the
least
heat of compression lost.
A coolant T-stat (Thermostat) would be ideally set for the highest possible
(allowable) temperature to do the following:
1) maximize the thermal efficiency of the engine
and
2) minimize the warm up time period where the most damage to the engine occurs
due to
water vapor condensation and degradation of the engine oil and corrosion from the
formation of sulfuric acid in the crankcase.
Since Rotax has chosen not to provide thermostatically regulated coolant temperature
probably due to a desire for weight savings, I would expect water temperature and
cylinder head temperatures to both track power setting.
An additional benefit of having a T-stat and consequently a higher coolant temperature
would be more cabin heat if you have coolant routed to a cabin heater.
I plan to incorporate a T-stat in my 914 installation and a coolant temperature
sensor
immediately upstream of the T-stat. I will also use CHT on each cylinder. In this
configuration coolant temperature will not track CHT. CHT will track power setting
and
mixture. One thing that I also wish were possible on the 914 would be an intercooler
which would greatly extend engine life. (The 914 is turbo supercharged.)
>
> I found the following at:
>
> http://www.rotaxservice.com/rotax_tips/engine_instruments.htm
>
> Cylinder Head Temperature (CHT)
> We found that many pilots confuse this instrument with a coolant temperature
> instrument, and sometimes label it as such. The probe to this instrument
> actually measures the temperature of the metal in your cylinder head. It
> allows you to monitor the proper operation of the liquid cooling system that
> cools your cylinder heads yet it does not measure the actual temperature of
> that liquid.
>
> Coolant temperature
> No provision for a coolant temperature probe is provided on Rotax 4-stroke
> engines and for good reason: the Cylinder Head Temperature instrument offers
> a better insight into the proper operation of the liquid cooling system and
> may reveal problems, such as the formation of air bubbles, that a coolant
> temperature instrument would not.
--
Paul A. Franz
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
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Message 6
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| Subject: | Wingtank.com tank install, ongoing |
I had heard several people mention the wingtank.com replacement tanks but I had
not heard anyone mention actually having them. Well my wonderful wife got me
a set for Christmas and I have just about collected all the bits needed for the
install, I still need to get a spray gun and a compressor. I thought I would
do a log of my installation for anyone who is interested in these tanks, I
also thought it might be mildly beneficial/interesting since I have never worked
with fabric and it has me a little scared still. Right now I am writing to
the guys at wingtanks.com because the instructions come across as having been
written by someone in a little hurry after having done their 50th similar install.
There just seems to be a few things glossed over as if the directions are
a formality and it all just falls together. I filled one of the tanks to rinse
it out and I got a little short of 5 1/2 gallons in but this was from bone
dry to filling the neck. I am trying to figure out whether I even need a sight
tube fuel gauge and how to install one if I do. And I am also trying to work
out a few other things but I will get to those as they start to make sense.
i plan on doing one wing at a time and I figure I will be able to remove a
wing and install a tank in about a day and it will probably take 2 weekends to
finish the painting but only time will tell.
James
--------
James
Kitfox 3 / 582 / GSC prop
The ink is still drying on my new certificate
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=280178#280178
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