DA 50 Cylinder Head TEMP

[Stainless Skills]

So last night I spent $70 on an infrared thermometer. One of those pistol looking things with a laser. It is awsome,

I have a DA 50 with a stock muffler that I am still breaking in on a 30% SD Yak with 32:1 Lawnboy. After another gallon I am going to try and use Penzoil at 40:1.

What are some good running cylinder head temperatures that a DA 50 should run at? What is the best? Is there a range? Is cool better? Can you be too cold? How hot is too hot? Are the temperatures different for different props? I am using a Vess 22A. I am getting 6800 rpm, should I be getting alot more? It seems so to me but I dont want to lean anything any more because the engine seems so hot when I land, but it does not fade on uplines, it just feels like there is play in the crank.

Any advice?

[Shoe]

My advice would be to contact the guys at DA. They are extremely helpful and will answer any questions you may have.

[RTK]

The temp after landing is a best guesstimate number. In-flight temps are more crucial. If you have good air flow and not running lean I would think anything below mid 200's would be fine for that engine.
What temps are you seeing??

[DATech]

Hi John
Like RTK said, it's hard to judge a lot by temps taken after landing. What part of the cylinder you shoot will make a difference also. Keep in mind that the temp gun is reading about 3/4" above the red laser dot on many of the guns on the market.

Something in the 210 to 240 range would be expected imediatly after shutting down. About 300 near the combustion chamber when running at full throttle.

On a side note, one customer reported 108 F degrees on his strong running engine..... Hmmm.... An internal combustion engine operating at only 10 degrees over human body temp...! Neat tools, but don't let it drive you crazy.

Our cylinders will start to show a "pinkish" hue when overheated a few times.

The lower end will feel a little loose on most engines when hot after a run.
Keep good airflow on the engine and don't over lean the high end and you should be fine.

Let us know if we can help.
Dave

[Bryan Mailloux]

I just did mine on the weekend. I checked the front bulge on the case. I was getting 135 deg. Still running 32-1 penzoil. checked right after landing.

[DATech]

PS:
Temps I mentioned above are on the cylinder near the combustion dome.
Dave

[Flyinhigh]

	Quote: Originally Posted by Bryan Mailloux
	I just did mine on the weekend. I checked the front bulge on the case. I was getting 135 deg. Still running 32-1 penzoil. checked right after landing.

I've noticed some of these infra-red temp units need to be callibrated, and I'm inclined to argue with the manual sometimes (stubborn, I know). I like to keep my engine indoors for an extended period (overnight) to confirm approximate ambient temperature (whatever the house is, or about 74 degrees f) then I callibrate the temp unit until it reads the same. So far it is working out well. I can callibrate the same unit to read much less on an engine too hot to touch, so proper callibration is certainly imperitive for accurate readings.

[bosshoss]

Dave,

I get a regular 210deg F on my exhaust port RIGHT after landing and immediate shutdown,.....this is after hard 3D and smoke oil.

2 questions....

Where would you put the heat sensor diode on the cylinder for a full time temp downlink???

And , does running smoke heat the engine up??..OR damage the engine in anyway??

[RTK]

Follow what Dave has said and you will be rewarded with many enjoyable flights.

I have done some in-flight recording lately and have found a lot of interesting things concerning baffling and temps. Most set ups I have seen with no or bare minimal baffling you will see at least a 40-60 degree difference in temps from the front of the cylinder to the rear of the same cylinder. A good baffling job can cut this to below a 30 degree difference. I am a firm believer in good baffling, a hot engine will produce less power and fail sooner. In some of my experimenting I was able to cut almost 100 degrees off of temps using good baffling and flow vs poor baffling and poor air flow.

Bosshoss--- if you can not run the sensor under the plug try to hit close to the top of the combustion chamber which should be about 2-3 fins from the top (double check that though) You also want to be on the cylinder wall between fins and not on the fins. I think you will find some interesting readings

Just to re-state. Tune your engine properly, baffle it, follow manufacturers recommendations and you will be fine. I only did my experimenting out of curiosity and to disprove a fellow members notion of what temps our gas engines really run at.

[Stainless Skills]

Does anyone baffle a DA 50 in a Yak cowl? I would actually enjoy the process but don’t really know where to begin and what to use. Should you just use some thick balsa sheeting and shoe goo and spray paint the balsa?

Is it beneficial to block off the whole front end of the Cowl like the EF 88'' guys do or just baffle for where your engine sits. I think it would be hard to try and curve sand a piece of balsa for the exponential slopes of the front of my yak cowl, any one have any advice?

[DATech]

Hi Boss
Near the dome, on a fin, as close to the fin base/main cylinder body as possible. A ring under the sparkplug is a very good spot, but be careful of maintaining the spark plug seal and depth in the cylinder.
Infrared imaging shows a wide range of temperatures on a cylinder. If testing/comparing both cylinders on a twin at the same time, I prefer the spark plug base area to get the most consistant reading.

Smoke oil can effect things. I haven't noticed a big heat change on our shop planes. Most setups will see a drop in rpm when smoke oil is introduced in the muffler, hence higher idle settings for low rpm 3D work when using smoke. If the oil is intoduced too close to the exhaust port, it can get back into the exhaust port. This is more of a problem on tuned canister/pipe systems that get a strong surge back towards the exhaust port at certain rpm. Not the end of the world, but it does tend to goop things up a bit at the exhaust port and even on the piston, etc.
There are other things like oil cooling the muffler and even changing muffler volume, which can effect engine performance also. Keep in mind, for better or worse, 2 strokes "feel" almost anything you do with the exhaust.
Dave
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Dave,

I get a regular 210deg F on my exhaust port RIGHT after landing and immediate shutdown,.....this is after hard 3D and smoke oil.

2 questions....

Where would you put the heat sensor diode on the cylinder for a full time temp downlink???

And , does running smoke heat the engine up??..OR damage the engine in anyway??

[juanes1969]

Stainless, I baffled my DA in an SD-Models YAK and therewas a thread about baffling a few months ago. Here are the links, my work on the engine baffle proved to bring down the temps on the engine. Maybe someone here can tell us of an easier way to do it after you look at the pictures.
http://www.flyinggiants.com/forums/fg68/14832-baffle-not-2.html
http://www.flyinggiants.com/forums/fg68/14832-baffle-not-3.html