Today's Message Index:
----------------------
1. 05:29 AM - Re: Temps (Tom Martin)
2. 08:02 AM - Re: Flight Test Progress (Ernest Hale)
3. 01:47 PM - Re: Temps (JOHNTMEY@aol.com)
4. 09:14 PM - Re: Temps (Fred Weaver)
Message 1
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--> Rocket-List message posted by: "Tom Martin" <fairlea@amtelecom.net>
The comparison of EGT values between cylinders is of little practical value.
Check this website http://www.gami.com/frames.htm for a very in depth
explanation. The short story is that you are only interested in the exact
temperature of a particular cylinder's EGT at the moment it reaches peak and
the fuel flow at that time. Ideally all cylinders should reach peak EGT at
the same fuel flow. The minor differences between EGT probe temperatures has
more to do with probe location in the exhaust system than it does engine
performance.
Cylinder #2 often runs hotter than one due to the fact that the
cylinder fins on these cylinders are not symmetrical on each side. The
front of number 2 does not have as many fins, as the front of number 1.
This is also why 5 will run hotter than 6. This is the reason that taking
air from the number six cylinder for the oil cooler is generally a better
location than behind number five.
I have been flying my rockets, using the gami philosophy, for eight
years. It will change the way you operate your engine and increase your
range and engine life. There are some very good articles on AVweb as well
regarding these techniques.
During this thread there was also a mention of leaning on final to
reduce engine popping. This will work but it might get you in trouble if
you have to do a quick go around. A rapid application of throttle may cause
the engine to cough, or quit, due to lack of fuel or be at such a lean
setting that it could cause engine damage in a full power situation. Yes I
am aware that we are supposed to push all levers forward for a go around but
it is better to already have the prop and mixture controls in the go around
position should the need arise. Engine popping on final can be greatly
reduced with a slower more gradual reduction of power in the circuit and on
final.
Tom Martin
-----Original Message-----
From: owner-rocket-list-server@matronics.com
[mailto:owner-rocket-list-server@matronics.com] On Behalf Of css nico
Sent: February 18, 2006 10:37 PM
Subject: Re: Rocket-List: Temps
--> Rocket-List message posted by: "css nico" <nico@cybersuperstore.com>
Isn't this standard for the cylinders closest to the initial airflow to run
the coldest? The same thing happens in water-cooled engines where the #1
cylinder closest to the radiator would run considerably cooler than the last
cylinder and would, as a result of that, show more wear at the end of the
engine's life.
I made some calculations on your temps as follows. Col A is the variation in
temp with the previous cylinder, while col B is the variation with cyl. #1.
Your readings show an overall cylinder head temperature spread across the
engine of 57 deg.
EGT A B CHT A B
1 1365 343
2 1396 +31 +31 389 +46 +46
3 1372 -24 +7 380 -9 +37
4 1385 +13 +20 380 0 +37
5 1367 -18 +22 387 +7 +44
6 1396 +29 +31 403 +13 +57
If EGT was a problem there would have been a (near) consistent variation in
CHT linked to EGT but check cyl #3 : the EGT is only 7 deg hotter, while the
CHT is 37 deg hotter. It could point to a cooling problem. Perhaps a baffle
is not installed properly or it is missing? Why #2, which shares the front
row with #1, runs so much hotter than its sibling, could be an injector
tuning problem because the CHT is higher consistent with the EGT. They
should both be cooler than the rest, unless there are other factors
influencing the cooling.
Very interesting! Just some observations - I am sure the gurus would be able
to give a clearer picture on what this story tells. :-)
Nico
----- Original Message -----
From: <JOHNTMEY@aol.com>
Sent: Saturday, February 18, 2006 6:50 PM
Subject: Re: Rocket-List: Temps
> --> Rocket-List message posted by: JOHNTMEY@aol.com
>
> Mine only has 15 hours and I'm watching analyzer like a hawk:
>
> >From last ride: Recorded at 3500', about 65F OAT, 20"/2400 rpm, 185 mph
IAS
>
EGT A B CHT A B
1 1365 343
2 1396 +31 +31 389 +46 +46
3 1372 -24 +7 380 -9 +37
4 1385 +13 +20 380 0 +37
5 1367 -18 +22 387 +7 +44
6 1396 +29 +31 403 +13 +57
> So, CHT for number 1 is notably cool... number 6 is the hottest.
>
> J Meyers N5800
>
>
Message 2
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| Subject: | Re: Flight Test Progress |
--> Rocket-List message posted by: Ernest Hale <ehale@cheyenne-enviro.com>
I have a terrible time with fuel pressure due to vapor lock as well,
any advice will be greatly appreciated, I have done just about
everything I can think of.
On Feb 17, 2006, at 6:15 PM, JOHNTMEY@aol.com wrote:
> --> Rocket-List message posted by: JOHNTMEY@aol.com
>
> Listers,
>
> N 5800 has about 15 hours now. Test period is 25 hrs. I've
> played with Vso
> and top end etc.
>
> I need some corelation on fuel capacity, unusable, and burn rate.
>
> I think I have 52 gallons max (bigger HR tank skins) ?
>
> 2.5 gallons unusable each tank, eh ?
>
> 14.5 gph at 20"/2300 rpm giving 190 mph indicated at 3500'msl
> (ballpark
> speed confirmed by GPS)
>
> I get some backfiring at random moments... and always when chopping
> for
> flare-out.
> Whats that all about ? Right now, it runs pretty warm, SoCal OATs
> were 60
> to 80 F.
> Mineral oil temp is around 200 +-10 and is sensitive to OAT. All
> EGTs line
> up and CHTs arent too bad. No.1 runs cool on CHT.
>
> When heat soaked on ground (and cruising) it shows signs of vapor
> effect,
> wiggles and lowering of fuel pressure... but it stabilizes with
> shot of electric
> pump.
>
> Anyone care to compare ?
>
> John Meyers
>
>
Message 3
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--> Rocket-List message posted by: JOHNTMEY@aol.com
Great thread (engine temps) !
A bit disconcerting though...
other than #1 running cool,I didn't know I had a problem. I'm still
thinking that nursing the baffles to warm #1 CHT up is OK.... then let this puppy
run for a few hundred hours.
do not archive John M N 5800
Message 4
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--> Rocket-List message posted by: Fred Weaver <mytyweav@earthlink.net>
Thanks Tom.... Aren't you still mounting the oil cooler at an angle behind Number
5?
Weav
-----Original Message-----
>From: Tom Martin <fairlea@amtelecom.net>
>Sent: Feb 19, 2006 6:27 AM
>To: rocket-list@matronics.com
>Subject: RE: Rocket-List: Temps
>
>--> Rocket-List message posted by: "Tom Martin" <fairlea@amtelecom.net>
>
>The comparison of EGT values between cylinders is of little practical value.
>Check this website http://www.gami.com/frames.htm for a very in depth
>explanation. The short story is that you are only interested in the exact
>temperature of a particular cylinder's EGT at the moment it reaches peak and
>the fuel flow at that time. Ideally all cylinders should reach peak EGT at
>the same fuel flow. The minor differences between EGT probe temperatures has
>more to do with probe location in the exhaust system than it does engine
>performance.
> Cylinder #2 often runs hotter than one due to the fact that the
>cylinder fins on these cylinders are not symmetrical on each side. The
>front of number 2 does not have as many fins, as the front of number 1.
>This is also why 5 will run hotter than 6. This is the reason that taking
>air from the number six cylinder for the oil cooler is generally a better
>location than behind number five.
> I have been flying my rockets, using the gami philosophy, for eight
>years. It will change the way you operate your engine and increase your
>range and engine life. There are some very good articles on AVweb as well
>regarding these techniques.
> During this thread there was also a mention of leaning on final to
>reduce engine popping. This will work but it might get you in trouble if
>you have to do a quick go around. A rapid application of throttle may cause
>the engine to cough, or quit, due to lack of fuel or be at such a lean
>setting that it could cause engine damage in a full power situation. Yes I
>am aware that we are supposed to push all levers forward for a go around but
>it is better to already have the prop and mixture controls in the go around
>position should the need arise. Engine popping on final can be greatly
>reduced with a slower more gradual reduction of power in the circuit and on
>final.
>
>Tom Martin
>
>-----Original Message-----
>From: owner-rocket-list-server@matronics.com
>[mailto:owner-rocket-list-server@matronics.com] On Behalf Of css nico
>Sent: February 18, 2006 10:37 PM
>To: rocket-list@matronics.com
>Subject: Re: Rocket-List: Temps
>
>--> Rocket-List message posted by: "css nico" <nico@cybersuperstore.com>
>
>Isn't this standard for the cylinders closest to the initial airflow to run
>the coldest? The same thing happens in water-cooled engines where the #1
>cylinder closest to the radiator would run considerably cooler than the last
>cylinder and would, as a result of that, show more wear at the end of the
>engine's life.
>
>I made some calculations on your temps as follows. Col A is the variation in
>temp with the previous cylinder, while col B is the variation with cyl. #1.
>Your readings show an overall cylinder head temperature spread across the
>engine of 57 deg.
>
> EGT A B CHT A B
> 1 1365 343
> 2 1396 +31 +31 389 +46 +46
> 3 1372 -24 +7 380 -9 +37
> 4 1385 +13 +20 380 0 +37
> 5 1367 -18 +22 387 +7 +44
> 6 1396 +29 +31 403 +13 +57
>
>If EGT was a problem there would have been a (near) consistent variation in
>CHT linked to EGT but check cyl #3 : the EGT is only 7 deg hotter, while the
>CHT is 37 deg hotter. It could point to a cooling problem. Perhaps a baffle
>is not installed properly or it is missing? Why #2, which shares the front
>row with #1, runs so much hotter than its sibling, could be an injector
>tuning problem because the CHT is higher consistent with the EGT. They
>should both be cooler than the rest, unless there are other factors
>influencing the cooling.
>
>Very interesting! Just some observations - I am sure the gurus would be able
>to give a clearer picture on what this story tells. :-)
>
>Nico
>
>
>----- Original Message -----
>From: <JOHNTMEY@aol.com>
>To: <rocket-list@matronics.com>
>Sent: Saturday, February 18, 2006 6:50 PM
>Subject: Re: Rocket-List: Temps
>
>
>> --> Rocket-List message posted by: JOHNTMEY@aol.com
>>
>> Mine only has 15 hours and I'm watching analyzer like a hawk:
>>
>> >From last ride: Recorded at 3500', about 65F OAT, 20"/2400 rpm, 185 mph
>IAS
>>
>
> EGT A B CHT A B
> 1 1365 343
> 2 1396 +31 +31 389 +46 +46
> 3 1372 -24 +7 380 -9 +37
> 4 1385 +13 +20 380 0 +37
> 5 1367 -18 +22 387 +7 +44
> 6 1396 +29 +31 403 +13 +57
>
>
>> So, CHT for number 1 is notably cool... number 6 is the hottest.
>>
>> J Meyers N5800
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
>
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>
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>
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