nonstoprc

My Feedback: (90)

Out of curiosity, I measured the temperature of the DA50 (immediately after landing) with a DuraTrax temp gauge. The reading was 230 F.

Just wonder if the reading is accurate. The gauge was placed about 1 inch to the front heat fins with the emissivity set at 34E. And i believe the heat fins at that time is too hot to touch.

Was the engine running lean? The high needle is 2 turns out. I am running ashless 32:1.

--qc

bubbagates

My Feedback: (32)

Yep, that's hot. I'm usually anywhere from 180 to 200.

Measure inbetween the 2nd and thrid fin from the spark plug

It could be you have too much prop on it or simply not getting air to the engine. You should be using a 22X8 prop but not a wide blade like an MSC since it will load it like a 23x8 Mezjlik or PT models prop

Your low end could also be too lean

nonstoprc

My Feedback: (90)

I am running Menz 22X8 so the load should not be a problem.

Do you use DuraTrax temp gauge to get 180-200F? If so, what is the emissivity setting? I was not sure if mine (34E) is correct.

--qc

PS. the plane is a WH edge 540 and the cowl openning exposes 4 head fins up front.

xtdsm

A way of making sure that your temp gauge is accurate is to spit on the area you are measuring and see/hear if it sizzles of not, if it does then you are temps are above 220f/100c if not then your temp gauge is not as accurate as it should.

I have been fighting this problem myself, first it was a fuel leak in the carb line, I fixed that which made things better but that was not it, I then baffled the engine and enlarged the air exhaust hole and that made things cool down alot. and if you are getting these temps by just flying around, then be sure that these temps will be a lot higher once you get into 3Ding and all (hovers and harriers will heat your engine quite a bit).

Ahmed

bubbagates

My Feedback: (32)

qc,

I'll look at mine when i get home as I have not used it in a long time but I'm pretty sure 34E is the setting.

You still could be a bit lean on the low end. With the high end turn turns out I suspect that may be the problem. On a DA50, there is a point when leaning the low end that the high end will no longer have any effect. That's the hard part of setting a DA50, you tune to remove the burble but end up too lean.

Since you are running LB at 32:1, I can asuume you are still breaking it in, so you do want it just a bit on the rich side, at least according to DA.

pe reivers

Reading temperatures after landing is very deceptive. It can only provide a general idea what happened in flight, when temperatures are that much higher.
There is a report on the differences here:
http://www.rcuniverse.com/forum/fb.asp?m=4968164

nonstoprc

My Feedback: (90)

I set the high to 2 1/4 turn out and it picked up 200 RPM yesterday on the ground. So looks like 2 turns out is a litttle bit of lean. Thanks.


pe revers,

adding baffles is a good idea. It could bit tricky for DA50 and WH Edge 540 hough because the engine is inverted and about 60% heat fins are already exposed. The baffle has to direct the air down first and then toward the center where the rest of the 40% fins are located.

--qc

pe reivers

In that case, the cooling already is quite good. It will improve with guide plates alongside the cylinder, and down-angled guides behind the cylinder that prevent stalled air pockets. This can all be blended into the cowling outlines. Fins outside the cowling get good cooling anyhow. It can be improved with fully enclosing shrouds though, if heat still is an issue.

Heat is an issue, when the engine starts out very strong, and once into flight, it looses power. That is, provided the mixture setting is slightly rich, on the verge of loosing rpm, to start out with. Richer mixtures will use the added fuel for the much needed internal cooling. As the engine heats up after a few minutes, running will improve with over rich mixtures.

Check your carb number. If it is a WT201, chances are that you can't get the carb rich enough. In that case, open the idle needle more, until you get very distinct burbling up to 1/2 throttle. This will help the high needle, and the engine will be at least 30 degrees cooler.

rcacro

The cylinders on my DA-100 measure about 150-160 degrees f after landing on a hot day. They were higher ( 210 degrees)before baffles were added in the cowl. The actual temperture will vary depending on the time spendt gliding to a landing, the amount of power used in landing and the length of any taxi time on the ground. Anything near 200 degrees sounds high if a nominal amount of time is spent gliding to a landing.

Scale Speed

My DA-50 is mounted on a TOC Yak 54 with a radial cowl. I used a Ziroli dummy radial cylinder with light ply back to reduce air intake. I opened up the dummy cylinders where the DA-50 is located and put short balsa baffles in. I have about 3-1/2 gallons of 32:1 through the engine and my average temps are 135 to 140 degrees when measured right at engine shutdown.

I have done the same thing with my Sukhoi with a DA-100 and the temps have never been more than 175. Both engines run great. At 230 degrees you are either running slightly lean or need to increase the air exit area to at least two times, preferrably 2-1/2 times the air intake area.

Full scale aircraft engines have air baffles for a reason.

Hey, anyone out there have any experience flying a Revolution 50 engine?

dirtybird

My Feedback: (5)

I have the in flight temperature monitoring system provided by Eagletree on a BME 100. The temperature probes are around the cylinder just above the exhaust.
During flight I observed 240 - 265 on the front cylinder and 260 - 285 on the rear. I guess its running a bit hot.

nonstoprc

My Feedback: (90)

Here is a pic of the cowl section of my WH edge 540. I am not sure if baffles can be easily built to cool down the DA50. Any idea? Maybe a better idea would be to open up the cutout for the engine?

I've also searched web on baffles for giantscale. Most applications are for twin gas engines and are highly recommend.

[img][/img]

RTK

My Feedback: (1)

Dirty, those temps are not necessarily to high. But If these temps are taken during some easy flying, I would redesign my baffling to lower them just a tab.


nonstoprc, You could baffle so that every thing coming in the cowl cheek openings are directed to the back side of the engine and out, and or box the sides of the cylinder at the lower cowl. It would not hurt to put a lip in front of the exhaust stacks on the cowl also, creating a low pressure zone helping pull more air thru and out.

dirtybird

My Feedback: (5)

The temperatures were observed in level flight at full throttle. The air speed was 67 mph at 6500 RPM. The peak temperatures were observed in a vertical climb. I did not notice an RPM drop in the climb.
I have full baffles around the engine except in the rear. I could use more exit area. I just wonder if this is normal. I have no experience with this.
The hotter cylinder is the one furtherest from the prop. Is this normal? I don't see any difference in the air path to the hotter cylinder. The angle of the prop blast might be the cause.

RTK

My Feedback: (1)

I do not think those temps are too high for a WOT vertical climb.
Have you read this? http://www.geistware.com/rcmodeling/...es/baffles.htm
Man that is a temp reduction

dirtybird

My Feedback: (5)

Thanks for the info RTK. The engine did not seem too hot when I got it back on the ground.
After reading Geistwares data I decided it was too hot