 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
BobbyPaulk(at)comcast.net
Guest
|
 Posted: Fri Jul 13, 2012 1:38 pm Post subject: CHT's |
 |
|
p { margin: 0; }p { margin: 0; }p { margin: 0; }List
I also have had serious problems getting the CHT's to a usable range. I finally got 1 thru 5 down below 300 deg but #6 is hotter running 310 ~ 320.
i have increased the height of the ram air ducts since I had the older style ducts with the plug wires on the outside. ( they are now on the inside ). I also installed baffles or dams and ground off an 1/8" at a time until I got them as good as they are going to get with this set up. . My question is what is a SAFE continuous CHT temp. The book says 354 MAX continuous and I know that cooler is better to a point. Is 320 continuous safe??
I am using a 51" pitch Sensenich prop which was recommended along with the 49". The temps are very sensitive to manifold pressure as the slide in the Constant Velocity Carb is always moving with the differential pressure. The 51" pitched prop may be drawing too much manifold pressure at a given RPM. I believe it to be a good match since it will turn 3350 in straight and level flight. BUT it will only turn 2350 static.
At reduced RPM ( 2200 ) all cylinders will be below 300.
I am going to try raising the lower baffle on #2 cyl as recommended by Paul. In theory that should reduce the flow and drop the pressure downstream ( as he said - "makes no sense" ). But worth a try at this point.
By the way - A friend has the new cowl with larger inlets ( from Pete ) and has had NO problems with temps.
Bobby ( age 74 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 156 hrs.
Do Not Archive
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
 |
AirEupora
Joined: 01 Nov 2009
Posts: 186
Location: Dixon, CA
|
| Posted: Mon Jul 23, 2012 6:25 am Post subject: Re: CHT's |
|
|
I have the 3300L and am having heating problems, but am slowly getting them in range. Right now I have only three hours on the engine. It's 100 degrees most days here in northern California. So I have to get up early to fly before it gets hot. Yesterday I quit before I started the flight because of the ground temps I was seeing.
I try to get off the ground before the CHT get to 302. I’m sitting here reading and I wondering if I'm put unnecessary limits on myself.
Paragraph 4.3 of 3300HL-IM
Warming Up Period, Ground Test
Start the warming up period with the engine running at 1000 RPM. Continue at 1400 RPM depending on ambient temperature, until oil temperature reaches 15°C (59°F). Check the two ignition circuits at 2000 RPM. Note: - RPM with only one ignition should not drop by more than 100 RPM.
DO NOT apply full power until CHT reaches 100°C (212°F)
DO NOT apply full power until Oil Temperature reaches 50°C (104°F)
DO NOT allow cylinder heads to rise above 150°C (302°F) during ground running.
Yesterday, I had to put gas in the plane before flight then taxi the length of the runway before I got to the take off runway. Halfway down the taxiway the CHT were too high. I had to shut the engine down because I was over the 302 mark on cylinder six.
I usually have to taxi out and shut down once I reach the end of the runway and point to plane into the wind. Oil temp are not at 104 degree for takeoff, but CHT's are very close to 302. If I sit there for three to five minutes the oil temp come up and I usually takeoff. My CHT's come up fast, but I have them where they don't go over the 358 mark until 1000 feet are so. I back off the power and push the nose over until I get some speed and watch the numbers on the CHT's. Most time I'm at 2500 +- 200. Once the temps come down I power back up.
My question is? Is the 302° temp something that I should watch closely on the ground or is it something that once I reach the end of the taxiway for takeoff I can get into the air with?
[/code]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
