Out of curiosity, what numbers might you have for;

DL50?

DA-50r?

I just dug up an older version of Eagle Tree Systems flight data recorder I bought when they first came out. I installed the temp sensor in the upper most fins of my DA-50r, and am waiting till the weekend to run it. So, I'm curious as to what temps I should see.

If you limit any of them to 155C you would do well.

He won't come even close to that with the da50

why? No power to turn on the heat?

Thanks!

Regarding the 3 responses I got; yours was factual & usefull, 2 others were useless.

Mine statement that it would be below 155C was in response to TOMs answer that 155C is a good number to shoot for or stay around, It all depends on your tuning, baffling, extraction and flying habits sensor placement, etc. I have no idea of those, There are many factors that come into play, but I will say it again, I doubt you will hit 155C.
Pe was just having a little fun, that's what makes these boards interesting to read.

Next time I get to Indiana I might have to check out some of the flying sites.

I can guarantee that if the head of a DA 50 wasn't exposed to the weather he could hit it. Tuned lean even exposed it could be done on a medium long upline. Just about all our engines have no trouble tapping that number under the right conditions. Just give him a nice round cowl Yak with no exit area aside from that tiny little scoop on the bottom. Done deal with those puppies.

Two photos here;
The one w/checkered pattern on cowl is the SD 260-Extra w/DL50.
{jug partially exposed}

The other photo is the GP Ultimate 1.60 w/DA-50r
{jug fully exposed}

You ould have to work hard to cook the Ultimate. The Extra likely runs warmer but is acceptable. There's no way to trap any heat around and behind them

Hey, get a life!
If you check all the words I have written on the subject here, you might just find a few useful facts. If you dont do your reading, don't be offended if I pull your leg.
The key in my response:
less power is less heat. Less heat is a cooler engine, even with mediocre cooling.

I work with some pedigreed program managers that can't put that together. They make a call for more power so you give it to them. Then they complain it runs hotter than the last one....... It gets better. After getting more power they complain they don't have flight duration as long as they did before. You can't win.

BTW, less than an hour at 210 and the front seals get to leaking oil. All this stuff should have some distributors reviewing their warranty claim restrictions

That's pretty warm for sustained opperation.

I have a great life and have no need to read everything you've posted on this.
If you'd posted your last two sentences (above) instead of what you did, we'd not be at this point.

From your sig line I take it you run a business, so I didn't expect you to ditz my choice of engines.
We all have bad days.....time to move on.

If I wanted a heated discussion, I'd just mention AMSOIL to T.O.M. and we're off!

That's total time. You're missing the point. Heat damage is accumulative. A few minutes here, a few minutes there....

I have a great life, and don't need to follow your every word on this subject. By your sig line I take it you run a business, so I didn't expect to get ditz'd for my choices of engines. If you'd responded the first time with you last two sentences (above), we'd not be at this point.

Time to move on.

Fuel chemical energy + Air => Combustion inside engine => Heat energy

Heat energy => Mechanical energy (applied to prop) + Heat energy (wasted to atmosphere)

More burnt fuel / time => More heat energy / time (Achievable with higher displacement (heavier engine) and/or higher rpm's)

Higher compression ratio => More heat energy / time (Premature explosion is the limit)

More Heat energy used as Mechanical energy (applied to prop) => Less Heat energy (wasted to atmosphere) (Limit is the lubrication and metals)

Here's the graph of cylinder head temperature from my GP Ultimate w/DA-50r gas engine;

Verticle bars are when flight data recorder unit was started each time.

Temp rise just before 3rd verticle bar is just before take-off where foam came out from under flight data recorder and I shut it down.

After the 3rd verticle bar is the actual flight. Highest temp (184.8F) was achieved during one of the sustained hovers.

At approximately 8min - 40sec the rapid temp drop occurs as the sensor came loose.

Where do you have the sensor placed??

Are you certain that's in farenheit? Check the values selected. I'm willing to venture it's Celsius, and if so you are frequently running in the area that damage is initiated.

Yep, it's indeed fahrenheit.

On this 2nd graph, look at the gauge on left, and text on lower right-hand bottom.

Sensor is against the cyl wall, between the two largest cooling fins, on the back side of the engine.

Right where the top of the combustion chamber would be??
I figured you would be a little higher than that if you were not tuned rich and had the sensor towards the top on the back side.

I've not seen an engine run that cold and run reliably.

It must be somewhat rich. I went from an inverted wrap around pitts style (twin pipe), to a stock (single pipe) muffler. It's now got a slight gurgle in low -to- mid range.

I'm flying a GP Ultimate 1.60 ARF at about 16.5# w/DA-50r engine, plus smoke system. It'll hover at 40-50% throttle.
Soon as I decide on which muffler to stick with (testing for smoke systems output), then I'll tune it better.