RE: DL-50 engine
 

LOL, i am so used to overpowering planes that i am used to ground clearence propblems. My late funtana x50 (sold) has an sk 91 2c in it ported for big props. I had a 16 inch prop on the plane and it was designed for 11-14 inch props.

RE: DL-50 engine
 

Trust me, hitting the ground with a 22" wooden prop on a 5.5hp gas engine gives "prop strike" a whole new meaning. Most of these guys can probably attest to seeing or doing that. If you're lucky it won't rip the firewall off.[:@][:@][:@][:@][:@]

RE: DL-50 engine
 

Not the Sword series. It is the PJE series with the varying pitch just like Vess. Here is a link: http://www.xoarintl.com/props/ma/PJE.html

RE: DL-50 engine
 

Interesting, First time I've seen those. Should be interesting to see how they compare to the Vess. They're using the variable pitch but don't seem to have changed the contour of the prop. Wonder how much difference that will make? Who's selling them?

RE: DL-50 engine
 

I couldn't find anyone stocking them so I had Abell RC order one from Xoar for me.

RE: DL-50 engine
 

I always order my Xoars from Abell. They always have the beachwood ply props I use.:D:D:D:D

RE: DL-50 engine
 

Oh yea, a prop strike on a 50cc engine on this Cap can and will loosen if not remove the firewall. Been there done that...Then you spend more trim time getting it right again, not fun. Now using a wood prop might help because the prop will take the brunt of it.

RE: DL-50 engine
 

I have a question on DL-50 when it is brand new (not seen a drop of fuel).

Does it give out a rough feeling when turning the crank shaft toward the TDC position? The roughness is felt when the piston almost at the TDC. This is like the ring rubbers something HARD at that spot of the cylinder.

My question is whether such roughness is common to DL50.

Thanks

RE: DL-50 engine
 

Nonstoprc, My motor was the same way. Bob at dlusa told me that when you first run your motor the first 10 min is the most improtant. You will hear a change in the way it runs after about 1 hour if you do the 2 hours of ground running. After the 2 hours also that rough feeling will go away. When you first run it make sure your needles are adjusted right. Not rich and not lean. and after awhile you will hear a change in how it runs then readjust the carb. I was told once that a new motor has square edges on the top and bottom of the piston ring from the machining process and after the motor is broke in it has a more rounded shape, because the ring flexes as it moves up and down in the cylinder. The scraping feeling is those edges on the ring.

RE: DL-50 engine
 

That's a pretty good description.

The ring rocks in the ring land to get a good scrape like a wiper blade. The breakin procedure on a 2 stroke is basically "seating the ring(s)" which will round the scraping edges of the ring (soften the edge some lets say) and knock off the high spots and sharp edges on the cross hatches too. They form a nice tight seal once the clearance from high spots is removed.

It wouldn't hurt to pull the muffler, lower the piston and have a look, some small port scratches on the piston are fine. Any metal shavings should be cleaned out then cylinder wall lightly oiled. Cylinder should be smooth and round except for the cross hatch scratches.

RE: DL-50 engine
 

And the removal of that edge on the ring needs more oil, And the oil can't be a good synthetic because it lubricates to well. Doesn't allow for the ring to seat as they say. Also that ring edge creates heat so a motor that is breaking in needs to be under a light load to keep that heat down.

RE: DL-50 engine
 

Thanks all for the fast response and will give it a break-in run tomorrow. From the exhaust port, I could not see any losing metal debris.

RE: DL-50 engine
 

What is the prefered break in for you guys. 2 hours running on the ground sounds SO boring.

RE: DL-50 engine
 

Just got the engine and no plane to mount on. Have to do it on the ground :-).

RE: DL-50 engine
 

Some people have built stands and broken these in religiously to the book and some haven't. I didn't get a book with mine and have never seen it. If you decide to, make sure you don't hard mount the engine to a steel frame, build a wooden one that will absorb vibration. Paul5992 made a very nice one. Personally, I ran mine long enough to tune it and cycle through the range a few times, about 15 minutes. (See my tuning video) I just take it easy on the flights, no hard core hovering, etc. (Like I can do any of that anyway! LMAO) I have never run an engine on the ground for extended periods and never will. It's my experience that they overheat when run too long stationary and the prop doesn't give the same airflow you get when flying. The prop also never unloads. Compare it to sitting in traffic on a hot day with a car and watching your temp gauge creep up. As soon as you start driving down the highway it goes right back down. I did start off with a 22X8 prop but went to the 23A shortly thereafter. I'm sure many people will argue this and have other views, they're welcome, this is just mine. Aerobob and Paul could probably tell you their experiences. Don't just go on one. Lot's are better! That's why we have more then one member on here!:D:D:D:D:D

http://media.putfile.com/DL-50-Tunin...-Vess-23A-Prop

RE: DL-50 engine
 

The manual on mine says 1 hour @ 2500rpm to break-in, which can be interpreted as accumulated 1 hour. Running at 2500RPM for a short period of time probably will not generate lots of heat.

I break-in my other name brand gassers in the air though.

RE: DL-50 engine
 

That would seem very reasonable. Especially if broken down into 4-15 minute sessions. Probably close to the total I had on mine. I think 4 hours is very extreme.

RE: DL-50 engine
 

1 hour would be good. Here is my stand. It lets the motor shake so you don't break the ears off.

RE: DL-50 engine
 

I have bench run one for the 4 hours. I have flown 2 for/thru the break in. Dl-usa says to fly it on break in. I would put it on a plane and fly it with confidence. The one on the the bench I made sure that the bench and mount had play in them as stated in post above. During that 4 hours the engine never stumbled of over heated and gave me the confidence in the engine to fly the next two in the air for break in. I did not take it easy as I fly 3-d and like to wring it out every flight. No problems. So whatever you feel comfortable with.

RE: DL-50 engine
 

I only did the first 2 hours at 2500rpms even though the book said to do the second two hours at 4000 rpms. I'm also doing most of my breaking in, in the air. Runs perfect.:D

Here you can hear me blip the throttle a whole bunch trying to get it to stumble or die. The only time it died is when I accidentally hit the kill switch going for the duel rates.
OOPS[:@]

I hit the kill switch at 50 sec in the video. And turned it back on befor the motor stopped turning.:)


Link removed by moderator as it redirected to off topic

RE: DL-50 engine
 

I know the instructions say to ground run for a couple of hours at very low RPMs but I really think that's just a waste of fuel and asking for a whole load of dust and dirt to find its way into the carby.

I ran mine for about 10 minutes on the ground to make sure nothing was going to shake loose and that it was reliable -- then I just flew the damned thing.

Lots half-throttle farting around with bursts of full throttle uplines and low-throttle downlines meant the engine wasn't under excessive load and got plenty of heat-cycling.

Now it runs like a top with a beautiful idle, great mid-range and *plenty* of power at the top end.

Providing you don't just burn holes in the sky for the first few tanks, I see no point in ground-running these engines for any length of time. Do DA recommend their engines be ground-run for a couple of hours?

I believe the likes of ZDZ advise *against* extended ground-running and recommend that their engines are run-in in the air where they get better cooling and a nicely varying load (for maximum heat-cycling).

RE: DL-50 engine
 

It would be interesting to know why D50 instructions (even the one posted on DLUSA webside) says 1-2 hour ground run @2500 rpm. There must be something in it if the vendor ("DL Power") dictates so.

This is not true for DA/ZDZ.


Sucking debris from ground while break-in can be avoided (e.g., raise the test stand).

RE: DL-50 engine
 

Everyone has an opinion, and thats great. But the reason for ground running is to get it running right. Run it in the grass with a hose near by to wet down the ground to keep the dust down if your that paranoid about a little dust. I ran mine on the ground because the instructions said to, and I'm glad I did. Because you can hear a dfference in how it ran after about an hour or 45 min. Its transition was better, the idle was better, the top end was better. Also I had to readjust the mixture screws on the ground run. That meens that the motor was breaking in. I don't like dead sticks. So I made sure it was running right on the ground. And you don't have to swear to get your point across. This thread is being closely monitored, and it would be great not to have another dl thread shut down.

RE: DL-50 engine
 

You've lost me there :-?

My point is that the DL50 seems to be so reliable and well made that there's *very* little chance of a dead-stick right from new.

Mine had the needles pretty close right out of the box and I flew it that way for several tank-fulls.

After the fourth flight I tuned the needles and have flown it that way ever since.

No drama, no deadsticks, not even a hint of a problem.

So no reason not to fly it right out of the box as I see it.

Another member of our club has done the same thing and his DL50 also runs fine and has never let him down.

I guess that if you've got a clean area and can be bothered there's probably little harm in all that ground running but it's clear that the DL50 doesn't really need it though.

RE: DL-50 engine
 

I did a couple of ground runs to shake it down and then did the rest in the air. I have never had a dead stick with this engine and now after 100 flights or so it is as strong as ever, awesome idle and transition. I cannot think of any really good reason why this engine would need a prolonged ground run in process, but if peace of mind is what you are after then maybe follow the manual?

Whatever process is used this engines rocks:D