rcguy59

My Feedback: (8)

I've seen a few of the XYZ 20's flown at the MRRCS field, Ernie. Can't tell them from the DLE until you look at the engine itself. Tom D. is quite pleased with it so far and has nothing but praise for it. Now that it's on sale, I'm very tempted. So far, I've gotten 3 DLE 30's, 2 DLE 20's, a DLE 35RA and a DLE 55 from Tom and I am very pleased with the results. The 55 was my first gas engine and it is now three years old and still runs perfectly in my TF GS P-47.

rcguy59

My Feedback: (8)

The Bowman ring Ernie refers to is purely optional. The Chinese rings are extremely hard and take a while to seat-in. The Bowman rings are not as hard and therefore seat-in quicker. The Bowman rings are undoubtedly better quality, but DLE's rings are still quite adequate to the task. Hope this helps.

armody

My Feedback: (10)

rcguy59,

So the factory fitted piston rings are little hard to sit with the piston and sleeve? That's why it needs to be changed?

Thanks

Mody

Ernie Misner

The Bowman ring is just a super high quality product that he makes by hand. No kidding, he makes a ring for most any engine you can think of and that's great for some that are out of production. Most users say they break in quickly and show an increase in compression. It's just a fun thing to do if you need a new ring or are finicky about your engines and want the most out of them. Some even say they idle better, especially after doing the reed block modification that he recommends on all the chinese, reed valved, 2-strokes. Run a search for that and you'll get pictures to go with the process and everything. It's just a matter of getting the reeds to seal flat against the block like they're supposed to do at rest. What I wan to know is how he goes about making a ring!

rcguy59

My Feedback: (8)

The other reason Chinese engines benefit from a softer ring is that the cylinder bore is not perfectly round, as it is not "bored" after casting and before plating. The cylinder is cast around a mandrel, then plated, skipping the boring process altogether. Certainly less expensive, but it doesn't result in a perfectly round bore. A softer ring seats and seals faster to the slightly less-than-round bore than does a harder ring. DLE 55's can take 5 gallons or more to FULLY seat a stock ring.

757jonp

My Feedback: (48)

Bad news and good news regarding the durability of the DLE 20! I've been running this one on a Mojo 65, and I haven't been nice to it at all other than feeding it it's recommended amount of oil. I had just landed and was at idle when it just stopped with a thud! Sure enough, tear down revealed a broken crank pin. (I saw where others had experienced this, so it wasn't entirely unexpected).

Now for the good news. Other than a couple very minor dings on the rod and piston skirt, there was no other damage. $30 bucks off to Tower put a brand new crank in my mailbox, 30 minutes of my valuable time, and it's off to the races again!

A couple of points here. I'm not particularly impressed that the engine failed of course. Looking at the broken crank pin I could see evidence of wear (galling), the bearing (caged roller) appeared to be in good condition, no discoloring of the pin, so I don't think it was running hot or under lubed, didn't even have much debris from the failure. Top end was very clean with little to no carbon buildup. Probably had about 3 or 4 gallons of fuel used total. Engine had been run hard and I'm sure has exceeded 10K rpm at times. (16X8, 9K+ static) This was an early engine (?), low 4000 s/n, bought it mounted, but never run, so no warranty, on my own here, but the price was right.

Hopefully the new crank holds up better? Kinda leads into my 2nd point here and the reason I'm running DLE engines. All engines fail. Some sooner than others, and for different reasons, hitting mother earth for one, abused is another, maybe just junk to begin with? Anyway, I needs parts. Tower sells DLE,s, has complete listing of parts in stock and the price is right. I think that's pretty tough to beat with any other brand out there.

Oh yeah, and the ignition curve sucks. I wonder if you can reprogram that?

acdii

Armody, the engine itself appears to be OK. I had to do a teardown as I felt some roughness in it, and turned out the full on ground strike, yes it did hit nose first, had pushed the crank back a slight bit.  Its nice and smooth again, but the ignition got beat up. The high tension cable came out of the box, so I opened it up, carved out the epoxy and resoldered it all back in, then filled it with fresh epoxy. This is what I hope still works. 

ahicks

My Feedback: (2)

Running the DLE 20 at really high rpm, then experiencing a crank pin failure is not that unusual? Several with that same experience have written in regarding that, with the same results. I think an engine turning the prop over 9k on the ground is just looking for trouble? Save yourself the trouble and find a bigger prop...

Bowman rings are great, but not a necessity unless you're looking for that last little bit of available performance? My engines, and the others I have first hand experience with, all run just fine without them? It's like any other engine popular enough to have aftermarket parts available for it. These engines are built to a price. ANY component on it can be improved on if you want/need the absolute best.
The question remains, what increase can be experienced, and do you really need it? Not a big believer in aftermarket stuff when the OEM seems to be working fine.

Regarding the XYZ, don't forget about the RCG 20's? Not trying to take anything away from XYZ, but having just one option for service parts makes me nervous....

-Al

757jonp

My Feedback: (48)

I would agree with Al in regards to the bowman ring. On the engine that I just repaired there was very little staining below the ring=very little blowby on the stock ring. I see no reason to replace it with an aftermarket ring.

9K to much? Possibly, but I use this one for 3D type of flying. I'm using a 17X6 Xoar now and we'll see how that does.

No trouble, just part of the game. Unusual failure? Time will tell on that subject. Right now it seems to be identified as the weakest link.

Ernie Misner

The XYZ engine has the same exact muffler bolt pattern as the DLE, so yeah, a pitts muffler for it is no problem. Not only is it no problem, but just tell Tom Denny at Valley View which orientation muffler you want and he'll ship the motor with that muffler for you. J'tec makes really nice mufflers for these engines, I've heard they are a little more substantial with nicer sound. When testing the XYZ engines, Tom says he put one on the test stand at WOT and left for an hour or so. Came back and it was still happily screaming it's guts out.

Funny that crank pin let go when it was idling. Obviously the damage had already been done, good thing it didn't let go at high rpm's though.

Ernie Misner

acdii

Sweet! The Pitts I have now sticks are a little more than I like, so maybe the ones listed there are slimmer off the head and will fit better on the Stang.

Ernie Misner

The XYZ looks identical to the DLE. Tom says they are actually a little different though and the parts are not interchangable. He had some input when they were designing the XYZ and had them put a genuine walbro carb and rcexel ignition on it, unlike the DLE. The XYZ is not made in the same factory as the DLE.

acdii

Well, I solved my lack of engine issue and placed an order for one. Depending on how they look and line up will determine which one goes on which plane. If the case dimensions for the mounting holes are the same, it wont matter, I can use it on the 4* which is already drilled for the Dubro mount I use with the DLE.  I do need to find a slimline pitts style for the stang though,  The ones I found so far are too fat off the head, and I dont want it sticking out of the cowl.

Ernie Misner

Like muffler, mounting dimensions should be the same?

microdon2

My Feedback: (47)

The crank pin went on my DLE 20 went in the summer of 11. I was cruising at about 2/3 throttle. As mentioned there were a few mentions of the same problem on RCU back then. Tower covered it under warranty. Haven't heard of any of those issues for a while (and today's story was of an older engine). Could be the newer engines don't have that weakness.

757jonp

My Feedback: (48)

I was a little off on the serial # of the engine that failed. It was F00669, and was purchased off a seller on RCU as mounted, never run. I also have one that I bought off Tower last year, serial # F04887. I wonder if the crankpin issue has even been addressed at DLE?

For giggles, I also pulled out the instructions that came with the engine. I can't find anything in there mentioning max RPM, only that it makes peak HP at 9K. I also note that one of the recommended props is a 15X8, which would result in excess of 9K easily?

Better late then never to read the dang directions, I see they're dreaming about using 93 octane go juice. I use whatever's on sale and didn't see any evidence of detonation, so I doubt that's a big deal.

rcguy59

My Feedback: (8)

Nine grand is too much. Period. I recently got two DLE 20's for my P-38. Since 3D flying hadn't been invented yet, it wasn't included in the design specifications for the P-38. Therefore I went for speed. The smallest recommended prop size is 14-10. I got a pair of APC's as it is my favorite brand of sport prop. A few minutes into each engine's first tank of gas, they were turning 9400+ rpm. The noise at that rpm was astounding. I never would have believed a gasser that small could possibly make that much noise with the stock muffler. With TWO of them 30 inches apart, the noise was truly oppressive. Needless to say, The balance of the 2 tanks each worth of running the engines got that day was at a setting well below WOT. I've since been told by flying buddies and Tom Denney at ValleyView that anything much over 8000 rpm on the ground is begging for trouble. When I told Tom Denney about it, said he would have the 14-10 prop recommendation removed from his website. Needless to say, those 14-10's will be given away, as I dont have any more glow engines larger than my OS .77VRDF. Please note that at the beginning of this thread, Jody never even bothered to test a 14-10. That should have been my first clue. Jody knew better, I didn't. Tom Denney told me that he and the ValleyView gang have had the best results with this engine propped for rpms in the mid-to-high 7000's. Hopefully I didn't damage my engines, even though I'm still under warranty. I think what may have saved me is that I run a pretty oily fuel mix for the first several tanks on a new engine. My theory is that until I'm fouling plugs, I can't have too much oil for the first several runs. Hopefully sharing my experience will prevent someone from converting one of these little gems into shrapnel.

Lifer

My Feedback: (1)

rcguy59,

Can you provide some details on your P-38?

armody

My Feedback: (10)

Guys,

Thank y'all for the great inputs. I have to run 3 to 4 full tanks on my DLE20 until I'm able to fly it. For fuel I'm using Klotz 32:1 with regular gas. Plug is CM6 NGK. In order to empty the tank, on what RPM should it be running until it burns out all the fuel? It should be full RPM for 40 seconds then idle for a minute? When do I have turn the motor off and let it cool for 5 minutes? I just wanna know the break in details.

I would really appreciate that.

Thanks

Mody

rcguy59

My Feedback: (8)

Sure, Lifer. It's the KMP ARF. 87" span, 63" or so long. Dry weight came in at 18 3/4 lbs. for a wing loading of just over 50 oz./sq.ft.. The manual calls for .46 2-strokes or .72 4-strokes. That means the DLE 20's should be just right. Funny thing, even with the DLE's, it still needed 3 1/2 oz. of noseweight. The kit came with retracts, but they are crap. I ordered a set of SpringAir gear three weeks ago and I'm still waiting for them to show up. Once the new gear is in, all I'll need is some decent weather for the maiden. Everything else is ready. This thing swallowed 22+ ft. of servo extensions and thirteen servos. If it turns out I need wheel brakes, there's another servo. Other people have flown these kits at up to 22 lbs. successfully, so mine is actually considered "light". My KMP bearcat has a DLE 35RA and at 42 oz./sq. ft. flies great and lands slower than you might think. High wing loading doesn't bother me too much as long as I pay close attention to my landing approach. Here's the Bearcat landing.

Lifer

My Feedback: (1)

Thanks! I wish they still sold the P-38.

acdii

No need to, just set the needles and fly. The engine will break in better flying than on the ground, you can easily overheat it on the ground. Just run it rich for the first gallon or so, then readjust as you see fit. You will know when it is time to readjust as the idle will start getting higher without touching it, so you can back down the servo idle, and retune the needles. These aren't like the glow motors where you run them a few minute WOT and let them cool down in stages. Think of these the same you would a weedwacker or chain saw. Fire it up and put it to work.

armody

My Feedback: (10)

acdii,

I'm thinking to hopefully get this baby up in the air soon! I'd be flying it without a cowl for few flights, once engine is pretty much settled, I'd put the cowl back on.

Thank y'all for your inputs

Mody

acdii

Thats pretty much what I did. I stuck it on a plane that I got for $30 with no cowl on it, and just ran it.  Then the plane turned out to not be able to handle the motor, put it on another plane that could and it started running better with each flight. 

Cactus463

I have DLE 20 in a Revolverengine runs grealt but find carb is veryvery sensitive to the smallest input-Have worked on servo and throttle arms to get the ssmallest movement possible-still one click on throttle gives about 3-4 hundred rpm increasehard to taxi-anyone else with this problem-???????