I like Slimline wrap-around mufflers myself. Solid construction and quite. I have one in service for over 4 years. No quality-related problem at all. RPM is at 7200 with VESS 22B.

True, the J'Tec leaves something lacking in the "looks" department, but then, so do many of us. I've lived long enough to understand "function" over "appearance", and in my experience this is one of those choices.

BTerry blew the whistle on your authoring manuals!!!! I didn't know that, perhaps many others didn't, but I also want to add my compliments to his. Your manuals are really very well done, informative, educational, and well-planned. VERY good work, Tim. Thank you for your efforts to make playing with our models easier for more folks by providing good documentation to get them up in the air.
Really.

Are you saying that I should replace the metal throttle arm with the phenolic one?

Do you guys remove the throttle spring so that there will be less lead on the throttle servo?

Tks

No No you attach the phenolic arm to the throdel plate that is there now, Remove the screw of the plate and place it back with the arm you need to drill a small seondary hole to keep the arm from sliding,
DO NOT remove the spring from the throdel shalft just un attach it from the arm only,

I jeave my throttle spring alone, incase of some type of failure it will help to move the throttle back down to idle or shut the engine down. I have been doing this for 3 years now and no ill effects.

It would be nice if the DL factory could produce a pitts style muffler.

Only if they made it a LOT more durable than the stock side muffler. I agree, though, and it would be good... But the J'Tec is $98.

Slimline muffler costs $109 and can be more cost-effective over years of use than other brands. Just my 2 cents over 4 years of use.

I am getting ready to get one of these engines for my Ultimate bipe. Any tips for the first time user? I am planning on getting a pitts muffler. Anything you guys could offer would be great.

I recall when I ran mine first time, I had to open up the low needle to about 2.5 turns out to get it started.

Some other hint.

. definnitely use nylon pushrod for the throttle servo
. PCM receiver is preferred
. make sure the mounting is solid as a 50cc engien is very powerful. For example, use 1/4" aircraft plywood for the firewall.
. balance the prop and tighten the prop bolts
. proper separation of receiver system from the ignition system (12" recommended by book). Do watch for interference induced by the ingition
. ask a field guy to check the setup before fly

Well, I’ve been posting that I replaced the Fuji 43 with a DL 50 on my GP 27% Extra 330S ARF. The Fuji ran great and always started immediately, but after flying the model for a while (sport flying and a few IMAC contests in the Sportsman class), I came to the realization that I simply needed more power. The plane flies GREAT with the Fuji, but vertical up lines that include partial rolling maneuvers are not symmetrical—the second portion any vertical up line, after the roll, is not the same length as the portion before the roll—she just runs out of steam on the way up. Similarly, I have been practicing inside and outside knife-edge circles and I usually need full power just to make it all the way around—especially when I get to the down-wind portion of the maneuver.

So, I did some research (reading posts on RC Universe and Flying Giants) and found that there are many happy DL 50 owners out there. Like most of them, I too wanted to save some money over the DA 50 which, consensus is I believe, is the benchmark for spark-ignition engines of any size. And since just about all the guys at work already own DA’s, I just wanted to “expand my horizons� and try a different engine.

Below are some pics of my installation. I was disappointed that I had to cut away so much of the cowl, but I guess that’s the price you pay for horse power! (The Fuji fit so nicely.) I also included some templates for some of the parts I made. The carb arm is from 2mm carbon fiber. Just print out the page and cut approximately 1/4� around the template. Use spray adhesive to glue the template to the carbon fiber (or fiberglass) sheet. Drill the holes, then use a razor saw (or a metal-cutting band saw if you have one) to cut around the partbut leave a little for sanding to the perfected, final shape. Finish with medium-grit sandpaper (or a belt sander if you have one of those too!).

I made the choke mount from 1/16� plywood, but will probably make another from carbon fiber later. The holes in the template are precise, but the inner, curved edge is an approximation that you'll have to fit your self—start by cutting it oversize first, then use a Dremel with a small sanding drum to perfect the fit.

The templates should print out to the correct size, but make sure you are printing 1:1 and take measurements off your printout before doing any drilling or cutting.

Also, none of these parts/templates are endorsed or approved by DL or any of their distributors—I’m just a regular guy here sharing my ideas. As of the posting of these templates and photos, I have yet to even turned the prop on my new engine (but I ran all over town to get my Lawnboy Ashles after work tonight!), so there are no guarantees. (I guess that’s my disclaimer.)

Oops, sorry. Looks like I can't download the templates because they are saved as a PDF. Hmm, I'll try to figure something else out...

Oh yea, please excuse the Zinger prop. I have a Mejzlik 22 x 8 on ordershould be here tomorrow!

Guys, I can't download my templates in PDF format on this site, which would gurantee that they come out to the correct size. However, for reference, I attched them in jpg format, but they will not print out the correct size. If you want, PM me with your email address and I can email you the templates. That's the best I can think of for now.

Sorry guys, one last thing here; This just occurred to me and I felt obligated to let you know; as stated on the cover of the instruction manual, the largest spark-ignition (gas) engine recommended for this plane is 43cc. Therefore, if you use a larger engine (like I am now), I don't know if Great Planes is obligated anymore to honor any warranty claims (due to any damage caused by using "too large" of an engine). This model has been tested to unbelievable (unreasonable?) extremes. And personally, I believe the airframe is perfectly capable of handling a 50cc engine if it is flown "normally," (I didn't say "delicately," just "normally") and we all know lots of guys will be putting 50cc engines on them, but I didn't want the fact that I am using a 50cc engine to be an endorsement by Great PlanesI'm on my own here.

Very nice and clean install.

This is a link to some pictures of a DL50 installation on my Ultimate, maybe they will help you a little on the engine installation. If you have any questions let me know.
http://www.lundyweb.net/Ultimate%20Pictures/index.html

Chuck

wel, I just bought a 22x8 JFX prop from my DL50 to start break in. What kind of numbers are guys getting with the JFX props? I am using 32:1 lawnboy for the first four gallons and then will switch to 45 0r 50:1 synthetic. also looks like 2 1/2 turns on low needle to get going?

I see the J'tec Pitts muffler comes in 2 sizes for the DL50.
The regular one is $89.99 and the large is $139.99. It says in their description, that the large Pitts Wrap Around has twice the volume of their regular Wrap Around Pitts muffler. Is this extra volume a big plus? Would it be worth the extra $50.00?
I don't remember anyone commenting on the J'tec large Pitts muffler, so if you have used one or seen one used in a plane let me know. I wonder what the physical size of these mufflers is? Neither web site gives any lengths, diameters, or angles of the mufflers.
The Slimline is $119.99 for the model made for the DA.
These are retail prices on the manufactures web site. Is there an alternate discounted source for these mufflers?
Why does it seem as if everyone is down on Pitts mufflers? Do they rob that much horse power? I wouldn't mind using the stock muffler that comes with the DL, but most of the comments on the stock mufflers is that it is too loud, not a good exhaust note, and they fall apart and need to be replaced occasionally. If I cut my cowl to accommodate the stock muffler, and don't like it, there will be a big hole in the cowl where it was.
The plane this will go in is the TOC/SD Yak 54.
There is a tunnel in the YAK that would allow cannister or tuned pipe. Would one of the aluminum bottle mufflers be quieter, take less horsepower from the engine, or have a more pleasant exhaust sound?

Greg

Has anyone tried the new "Silent Beauty" pitts muffler now offered by TBM?
The price is $65.00, but they're backordered right now.

I have a J'Tec on a AW Yak which I really like, but have had good luck with the stock DL muffler on a WH Sukhoi. Yeah it's a little loud, but where I fly that's not a problem. A while back I botched a landing and bent the down pipe, so I cut part of it off and it's worked fine since, although it's louder. Bob at DL said the length doesn't matter except for sound

If you can afford a canister that would be the way to go they do not rob the engine of horsepower and are alot more quiet.

Hey, can anybody tell me how I can post the templates I've referred to in my post (#2033) - the ones with all the photos? It's a PDF, but apparently this site won't take PDF's.

Is there another site where I can download the image, then do a link or that URL deal?

Thanks if you can help!

Tim

What actually constitutes when a muffler becomes a canister?
I am assuming the large J'tec Pitts doesn't have any baffles in it.
I thought a canister had more than 1 chamber, and the exhaust gas is forced to change direction by using pipes and baffles with holes in them.

Greg

Tim - very nicely done, clean and neat.
Couple of things;
1. Do you have adequate "exit" openings in the bottom rear of the cowl? Even with the front of the fins exposed, without adequate "exit" openings, you will have heating problems.
2. Distance from firewall/carb intake opening. Many of us have found that we get better performance and smoother transition, consistency of throttle if the intake hole is cut in the firewall so the carb can breathe better. Yours looks very close.
3. Secure the hall sensor connection where it plugs into the wire going to the module. String, dental floss, fancy clips, whatever, but those need to be setup so they won't unplug themselves. Same with battery and module power input wires wherever they are at.

Really a very nice install.

Greg, I believe your definition is probably as good a one as has been written. Canisters that are manufactured have exactly what you're talking about. The reason they have "tuning" effects is the restriction of the first chamber created by the baffling separating the input tube with it's holes from the expansion chamber with it's exit nozzle. There a some pretty dang good "do it yourself" canister plans floating around made from a variety of things, but nearly all of them meet the "tube with holes, baffle, and expansion chamber" definition.

I have not had the large volume Pitts from J'Tec, but have used (and still do) the "standard" volume/size for the DL 50. I think it has a much mellower tone than the stock muffler, and doesn't rob power from being too small. My experience with Slimline is that they are fine quality products, but tend to be a little small in their chamber sizes, and when I've used them, reduce rpm by restricting too much. Others have reported other experience, so there may be differences in perceptions or expectations.

If you are flying someplace where loudness is an issue, or will be, I'd recommend a canister/header setup from the get go, whether it is a purchased system or home-made.

Hi Bob. Thanks!

1. Airflow exit - The aft edge of the bottom of the cowl is already cut back quite a bit. It comes from the factory this way. I think it should be sufficient.
2. Space between carb and firewall - I was wondering about that. The current space is whatever it would be with the stock standoffs (about 1/4"?).
3. Wire connections - if you look in the photo you can see the conection on the top of the engine box is secured with heat shrink tubing. Then, the tubing is tack-glued into place with a few drops of medium CAsame for the other connection that goes to the switch.

I've got awesome templates for mounting the engine and a few other things, but I can't upload them to this site because they are PDF. I'll see if I can have them converted. I'll PM them to you right now.

Thanks again!

Tim

This thread has been on fire the last few days, but now it seems a little slow.

Anyway, my first flight report;

I'd have to say my mood right now is pleased, bordering on giddy. The engine started on about the fourth, fifth, sixth, whatever flip. Idle was nice. I didn't touch the needles and ran it on the ground (in my plane) for a few minutes. Shut if off, made a cursory inspection, started it again (2nd, 3rd, 4th? flip), ran it for a few more minutes, then put the petal to the metal! She was running nice and rich..."Baaah bahhh bahhh bahhh" throughout the whole range, though it would clean out a tad nearer full throttle. I just circled around for a while, then tested a few uplines. Wow! Even running rich (fuel/air and gas/oil ratio) she just keeps going up and up - slowly, but just the same! I have to say the plane just flies better all the way around. This is a "real" engine man! And swinging a 22" prop the plane really slows down nicely when coming in for landings. Can't wait to try some more down lines. On a sharkstooth I can pull the vertical, get in my half roll, continue on the vertical for as long as I feel, then not just barely "flop" over the top with hardly any control response, but I can actually push over the top with a nice radius still having enough prop blast and airspeed to maintain control.

So I got in two flights tonight and hope to fly out the remaining break-in fuel (two gallons Lawnboy Ashless 32:1) tomorrow, then make the switch over to the synthetic at like 40:1 or 50:1.

I know. I know. Talk to you at the end of the summer or after a few years when I have many gallons of fuel through the engine. But indications at this time are that this should be a fabulous engine.

Can't wait for the break-in to finish and for my Mejzlik to get here!!!

I'll check in later.

sweet boss man

When you come in for a landing shut the engine off and check for bearing play by grabing the prop at the ends and push one side in and the other side out to see if you have any play in the bearings,

We had at are club Two DL engines that had bad casing and the bearings and crank was loose in the engine from that,