lml@lancaironline.net Mailing List Archive

Jay et al - Climbing at 2500-RPM, WOT and full mixture is not a problem... neal -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Jay Phillips Sent: Monday, August 11, 2014 9:33 AM To: Lancair Mailing List Subject: [LML] Re: TSIO 550 Climb profile I'm signed up for the GAMI class in October. I will see what they say about it and report back here. I'll also ask Neal George what Continental thinks of it. Jay Phillips -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Bob Rickard Sent: Monday, August 11, 2014 4:14 AM To: Lancair Mailing List Subject: [LML] Re: TSIO 550 Climb profile Not to hijack the thread, but what do the engine experts say about reducing RPM only at WOT? I seem to remember that moves Thetapp to a bad place and increases cyl pressure higher than ideal. Would love to hear what the Experts say Bob R On Aug 10, 2014, at 3:57 PM, "Jay Phillips" <jayph@fastairplane.net> wrote: I'm going to have to take back what I said about climb speeds, at least conditionally. For comparison, the general take-off and climb profile I use is as follows: Take-off: 2700 RPM, full-rich mixture, WOT, yields 38.5" MP, and about 42 gph fuel flow. I stay with this until I reach 1500' AGL, then reduce RPM to 2500 and Throttle to 31.5" MAP. I then climb using these settings and 165 IAS until I reach cruise altitude. I struggle to keep the hottest cylinders (#3 & #4) below 400F. Total flight time from lift-off to 17,500' MSL (starting at 5,100' AGL field elevation) is typically 20-22 minutes at an average burn rate of about 25 gph. This morning I performed a test: at 1500' AGL I reduced RPM to 2500, but left WOT and full-rich mixture. I set the AP for 145 IAS climb to 17,500 MSL (starting at 5100' field elevation). Total flight time was 11:05. Fuel burn average was around 35 gph. The best part? Hottest cylinder (#3) never went over 380F. 25 gph for 20 minutes = 8.3 gallons. 35 gph for 11 minutes = 6.4 gallons. So the WOT climb profile is faster, burns less fuel, and keeps the cylinders cooler. Anyone see anything wrong with this? Jay Phillips -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Jay Phillips Sent: Thursday, August 07, 2014 4:28 AM To: Lancair Mailing List Subject: [LML] Re: High CHTs on #2, TSIO 550 Thomas, I had a similar problem when I first bought my IV-P - #2 ran hot during climb, and I could alleviate it a bit by partially closing the oil cooler door. The back side of the #2 cylinder is right up against the forward side of the oil cooler. It doesn't leave much room for airflow. I had a modification installed (don't know what it is called, but any shop knowledgeable on IV-P's should know what it is) that added some concavity to the front side of the oil cooler, providing more room for airflow around the back of the #2 cylinder. In my case, at the same time we discovered I had a burned exhaust valve on the #2 cylinder. Whether that was related or not I'll leave to the engine experts. We also changed the baffling around the prop hub to better control the airflow. After all was said and done (including an engine overhaul - different problem) my #2 CHT now behaves and #'s 1,2, 5, and 6 are pretty close in CHT. #'s 3 and 4 are now my warmest. I still don't have it where I want it but it is a lot better. I think your IAS during climb is too low. Try using 165 or 175 IAS for climb speed and see how that affects things. Using 165 I used to have to level off at about 13,000' to allow the airspeed to climb and provide cooling air and time to bring my CHT back down. Once it was trending downwards I would continue the climb. You don't mention your MP during climb. I used to (and still do sometimes) used 31.5" during climb. One suggestion I received was to continue climbing at WOT. That helped a lot although it uses a lot of fuel. I've also tried lowering power to somewhere between 27.5" - 29.5" - that also helps. If you haven't already you should check compression and put a borescope into #2 to make sure something else isn't going on. Jay Phillips -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Thomas Whalen Sent: Wednesday, August 06, 2014 1:20 PM To: Lancair Mailing List Subject: [LML] High CHTs on #2, TSIO 550 I have been fighting for over a year to try to keep the #2 CHT below 400 dg on the climb. It has hit as high as 430. I leave it full rich and climb at 140kts. When I level off, I then LOP and then #1 cools off. I have the Lancair baffles and RTV the gaps with the engine and have a good baffle seal. I even covered my 3rd intercooler and that only helped a little. Behind the prop the baffle seals up to the top cowl but not down to the bottom. I have seen it the reverse of that as well. If close the oil cooler door the CHT will drop 5dg at times. This was a factory new engine. Any suggestions? Thomas Whalen N444TW -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html