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Colyn, I have the air guides underneath – it’s may be worth checking if #4 closes as tight as the other ones. It will take a little bit to give you more data. I need to take another flight for this and I just took everything apart yesterday for the annual. As soon as I am ready to go again I get you the data. Thanks
Ralf From: Colyn Case [mailto:colyncase@earthlink.net]
Sent: Tuesday, April 17, 2012 4:55 PM
To: lml@lancaironline.net
Subject: Re: [LML] Re: TSIO 550 Hot #2 cylinder Ralf, what is the fuel flow in each of these scenarios? as you lean, when does #4 peak relative to other cylinders and what FF? do you have air guides underneath the cylinders to keep the cooling air going through the fins all the way to the bottom of the cylinder?
Since we are talking about hot cylinders I got one question that bothers me: I have a plenum and I tried to do a very anal job in sealing all the leaks around the engine – I followed Fred Moreno’s instructions there. I have different temperature patterns amongst the cylinders for different situations. LOP cruise: #2 is the warmest and is usually between 330 and 370 depending on altitude, humidity, fuel flow etc. – always very cool no issue at all Climb 32” MAP, 2500 1/min, full rich : cylinder 4 wants to get warm and I keep the airspeed around 180 in order to stay below 400F. This is the situation I am not really happy about – if I don’t pay attention on a warm day the #4 will get above 400F Climb 2500 1/min, full rich, full throttle: even temperature profile amongst the cylinders. Engine runs generally cooler and airplane climbs faster. I tried to watch the EGTs and see if #4 is running lean but I could not tell a difference in the EGT. #4 has the dip stick pipe and more hoses that could influence airflow. Any idea why #4 is warmer at 32”? Pete, can you post pictures of this scoop and oil cooler box? Thanks Sent: Monday, April 16, 2012 5:14 AM Subject: [LML] Re: TSIO 550 Hot #2 cylinder #2 was also my hottest cylinder. First I installed the cupped insert that was listed in one of the on-line articles that allows the air to flow around the shallow fins on the oil cooler side of #2. I learned that TCM cylinders have asymmetric depths on the fins on the left vs right sides. The left sides have very deep channels between the fins, while on the right side the cylinder barrel comes right up to the top of the cooling fins. This means that the oil cooler box effectively blocks the cooling air from going around to the lower right side of the cylinder. However, even with the cupped insert, #2 was still my hottest. At that point I remembered that my engine, which I got from a salvage of Adam aircraft inventory, came with a piece of baffling for the oil box that had a scoop installed inside the oil box that directed air around to the lower right side of the cylinder. The scoop was ¾” deep at the top and flush at the bottom, and about 3” wide. I moved this scoop from the discarded Adam baffling piece onto the Lancair oil box (the hole was nearly the same size as the previous dished shaped part I had installed before). Not only did this solve my #2 CHT problem (it is now one of my coolest cylinders), but it did not noticeably affect oil temps. A win-win. Looking for advice for this problem. Oil cooler door may help a little but the trade off of oil temp increase vs CHT increase is a trap at high power climb and in slow flight. Two hours of flight time and problem is consistent up to about 8,000 or 9,000 ft. One idea suggested is to fair the inside top of the intake cowl on the left side because turbulence here will decrease the airflow to the top left side of the engine. One person indicated he did this with a IVP and achieved a 20 degree drop in EGT by doing this. Anyone else have experience with that? Thanks in advance and to those who have sent congratulatory emails. |
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