Part 2

Scott, you are to be commended for your willingness to share such details in support of the brand. I'm sure that I speak for everyone here, that YOUR information to us is priceless. No joke.

Keep it coming.

Scott, awesome work! Thanks for sharing it with us.

Real nice Scott many thanks,

I had two DL 50 to repair do to the bearings be came lose in the hub, I did lock tight them back in but be for I did that I drilled and tap for two set screws two in the front and two in the back, that was three months ago and they are doing just fine, your pictures will help a lot of folks out there,

Jolly good job mate,

No worries Bob. I've been married 35 years. I don't get offended easily anymore.

I have flown gas since the late 80s and never had radio controlled kill switches till I tried that optic isolator this year. All those years, we never wanted to combine the two systems for fear of radio interference. A problem that is rapidly going away with 2.4 systems more widely used. I, however, have not made the jump yet. Till I do, these optic isolators will probably be in more of my aircraft. It would have helped my in this incident for sure. I have had radio chokes on some, but unfortunately, not this Yak. That would have done the trick as well.

I'm at 27 years... I understand

Thanks.

Not a problem, happy to help!

Ive got more to go yet, got the putting it back together pics to upload shortly

Cheers

Keep em coming Bob. I enjoy your informative posts.

All I know is I need to stay off the forums. Thinking about ordering my third DL50.

Never mind the thinking about it part....I just ordered it. Time for bed.

OK Heres how to put it back together.

disclaimer disclaimer disclaimer - if you dont think you can do it properly or dont have the right tools dont do it. Pay your nearest dealer or small engine shop to do for you.

Again photos tell the story, but some key points.

CLEAN / Remove all traces of bearing retainer/thread lock from crank, bearing housings, prop hub, woodruf keyway. Everything needs to clean & shiny before installing new bearing etc, they will slide in far easier if everything is clean. And the new loctite will work much better if it has clean surfaces to bond too.

Dont forget to install the spacer on the crankshaft before fitting it back into the case or you can damage the bearings when tightening the prop hub back on.

When tapping the prop hub back into place, support the centre of the crank at the opposite end with a bit of hardwood dowel or similar between it an the bench so you are not putting force onto the conrod/bigend or crankcase. You only need to tap it in far enough to get the prop shaft to thread back on, tightening up the prop shaft will pull the rest together if you do it while everything is still hot. (keep the temp up with the hot air gun as you go)

Warm up the crankcase to fit the front bearing (leave the bearing cold).

Warm up the main bearing, not the crankshaft to fit the main bearing back on the crankshaft.

You can tap the main bearing onto the crankshaft using a bit of pipe with a 15 - 16mm internal diameter that will slide over the crankshaft and rest on the inside bearing race. You dont want to be bashing on the outside race or the seal otherwise you can/will damage the bearing.

Warm up the crankcase again to fit the crank ( with main bearing installed) back into the case.

Go easy with the thread locker & bearing retaining compound. You dont need excessive amounts, clean up excess as you go with a clean rag. It goes off pretty fast, especially when everything is hot, so dont use it until you are ready.

Make sure everything is clean. Clean bench, clean rags, work on a bit of cardboard or similar to protect the finish of the engine/casing halves.

Have everything you need to hand/within reach, so you can get the bearings/crank in place with the case still hot. (leather gloves too)

When you fit the case halves back together you will need to use a bit of gasket type sealer between the halves, and the loctite used for retaining the bearings is thin, and fuel proof and will normally suffice. If you want to lash out you can buy loctite 518 or 573/4. But the fit between the casings is normally very good, and all we want is something to help seal the join.

Fit piston/wristpin/bearing and wristpin clips - make sure the clips are properly in the groove on the side of the piston, and the tails/clips have not got any nicks in them. If the tail comes off one of these clips or the clip finds it way free it takes out the piston, ring and often the cylinder. Weve only had this happen once...but Ive seen it happen to other big name engines too.

Make sure the piston goes back on the right way around, the split in the piston ring faces away from the exhaust port. Use a little oil on the ring, and inside the cylinder when refitting the head to help things slide on. You can hold the ring compressed with your fingers as you slide the piston into the head. Again, make sure exhaust port is pointing in the right direction. There is an arrow stamped on the head of the piston that normally points towards the exhaust port...but double check as we have had a couple with the arrow stamped on the wrong way.

Use small amount of blue loctite on all the bolts for the casing/head and tighten evenly in criss/cross pattern - same as when you do up wheel nuts when you have a flat.

Double check everything, crack a beer, sit back and admire your work!

PART 1

PART 2

Very nicely done!

Are you sure that the Beer comes after reassembly or be for assembly?

Super nice job there mate,

Scott (dlenginesaustralia),

thanks for the pics and the instructions. Wonderful!

Couple of questions;

1. Why in the world is the bearing lock used on the woodruff key and the front hub? For the bearings I understand it's to keep them from spinning in the case or on the crank, but why on the key and front hub?

2. Well, I guess a comment, not a question. When I was disassembling my engine, when I got to the key it didn't look like the one in your photos. Althought it was difficult to tell for sure because I never got it out of the crank, it was black and looked just like a piece of sheet metal or something. It seemed to be fairly soft metal as when I tapped it with a hammer via a screwdriver it just kind of dented and deformed easily. The key in your photos looks like the good kinds that I've seen that come with O.S. engines. Wonder what was the deal with mine.

3. This one's a question; Apparently, you are using the stock DL bearings. But do you ever use or do you recommend any kind of "super bearing" like something available from Boca Bearing or another bearing supplier? I get the idea that while suitable, maybe the DL bearings are "standard issue," but one could get even better bearings if desired.

Oh well, I'll have a new crank assy. coming soon, so when I put it all back together I'll have a brand new bottom end so it will all be clean. Gotta run out and get the bearing seal this weekend so I have everything ready when the parts arrive.

Oh yea, I made a hub holder tool like yours only out of 1/4" plywood. Worked fine for removal.

Thanks again!

Tim

Hi guys,
I need advice. I have a CMP P40 Warhawk 140/73". Will this DL50 fit nicely inside the cowling without having to make holes on it..?

No worries!

I dont really see the big need for the loctite on the hub/woodruf key either.

They come like that from DL so we are just keeping with thier standard. Though the woodruf key on this one seemed to be loctite free. The woodruf key is pretty soft and does end up with a dent in it when removing, but if just can tap once or twice vertical enough to move/free it, then tap it out at an angle away from the crank (rather than down) it seems to pop free with any further damage. Comes out easier if you warm it up with the heat gun too. If you give it too much with the screw driver it dents/deforms.....maybe this is the reason for the loctite on the hub/shaft to help reduce the twisting load on the key when things warm up maybe?

The bearings that come standard with the DL's have been good bearings, originally they where F.A.G bearings from germany, but now they have a Japanese (made in Germany) koyo on the front and a F.A.G brand bearing on the rear. They are good bearing (which is one of the areas the DL differs from some other engines out of China) and I havent seen the need to change to something else. Going super high spec I dont think will gain much, except to lighten you wallet.

Hub holder out of ply does the trick, thats what I made the first "prototype" out of and easy to do with a prop jig & spade bit. Good point!

Before, during, and after! keeps your hands cool in between handling the hot parts.

but I also fly mode 1, so cant be during flying unless I get one of those caps with the straws & can holder.

Great job. What kind of camera do you use? Seems like it has a macro lens on it.

IMO, too much engine for this plane. The way oversize engine would mean more weight in the tail to balance and make your wing loading even higher. War birds have smaller tail components and this higher wing loading will be most evident when landing. Tip stalls can ensue.

This engine hauls my 85" Yak through knife edge loops and vertical take offs. A 180 size (30cc) would be more than enough (still overkill), and this from a guy who likes lots of power in reserve.

Hi ram3500-RCU..
Thanks for your advice. To compare a 26cc and DL50...;

SV 26cc
Engine type: single cylinder, 2-stroke, air-cooled
Bore x stroke: 34 x 28mm
Piston displacement: 25.42cc
Max. power: 1.75KW(2.35hp)/8,500rpm
Max. torque: 1.5NM/7,500rpm
Rotate speed: 1400-9000RPM
Compression ratio: 8.4:1
4.8-6V Electronic ignition
Carburetor: Walbor pump type/diaphragm
Start mode: Electric Start
Dimensions: 190 x 120 x 220 mm
N.W.: 1215g(with muffler and electric ignition)

DL-50 Spec.
CDI Electronic Ignition.
Walbro Carburettor
Performance: 3.88KW(5.2hp) @ 7500rpm
Idle: 1350rpm
Thrust: 13.6kg @ 100mtr / 11.5kg @ 1800mtr (Above sea level)
Suggested prop: 22x8, 22x10
Spark Plug: NGK CM6
Bore/Stroke: 43 x 35mm
Compression: 7.5:1
Weight: 1350g
Fuel: 2C Regular Gas mixed 30:1 - 45:1
Walbro membrane pump carburetor with manual choke
Automatic advancing electronic ignition

There's a different of 135g in weight. and huge in different in power...Ya, I agree, that would be more than over powered. Do you think the SV26 will be just enough for it? I actually want it to be slightly over powered, but I can't find a gasser slightly bigger than 26cc. I know there is one, SPE28cc, but the carb. is on the side of the engine, not behind it. I'd rather not make any hole on the cowling, to maintain the scale look.

Would this extra weight of 135g affect the performance by so much..?

For a Warhawk, NO. Simply fly it fast And prop your engine for 7500 or a little more static rpm 10 or 12 pitch. It'll rock!!

3W-28i is rear-intake, narrow engine. Beaucoups power, and will help avoid tail-heavy situation without being insanely, stupid-overpowered like a DL 50 would.

In addition to what Bob said...You'll find that with warbirds, they generally fly BETTER at the heavier end of their appropriate wing loading range. We've had two nearly identical P47s at the field, same size, approximately the same power. One weighs in at 18lbs, one at 28lbs....guess which one flies better?

Chad

Do you the link Bob? For the engine...?