RysiuM

My Feedback: (1)

For 25 bucks I can't be wrong

16 inch is just fine. I'm sure it will have more than enough power than I will ever need. It is scale model of the plane that can't even make loop or roll. The narrow wing and slotted flaps shuld make stall speed low. I'm sure it will fly. I was thinking about bigger prop just because of the scale look, but if I have to live with 16 inch - I will.

I just weighted the engine again this time without the prop (and no muffler - should arrive any time). Exactly 3 lb 4 oz. Muffler weights 4 oz, so my setup is the same as other guys have. I still can cut off the old fuel tank mount and save 1 oz.

Here are the pictures of the mount. You can see I didn't use the old fuel tank mounts. I still keep them just in case. But when I see my mount doing fine while engine is running, I will remove them.

RysiuM

av8tor1977

My Feedback: (6)

An engine that will swing a 16 x 8 with any authority should do ok with an 18 x 6 prop as the loading is approximately the same. You are just trading diameter for pitch. The 18 x 6 will have more static thrust and less airspeed. Just the thing sometimes for a big, slow airplane. The APC props don't look very "scale" sometimes, but they are very efficient and what I always use and highly recommend.

Good luck,
AV8TOR

RysiuM

My Feedback: (1)

The muffler from [link=http://wackerengines.com/]http://wackerengines.com/[/link] arrived today. It is a real beauty. It doubled the value of my engine but it is worth every penny tho. Thank you, Pete. If this engine meats the expectation I will make another one. Then I will need another muffler so I will make you up on short shipping.
The only problem is that the engine can't be shipped to California, so I will have to pick it up somewhere else.

Now I need to make some kind of test stand and I will try to run the engine this weekend.

RysiuM

RysiuM

My Feedback: (1)

I have a little problem. The muffler doesn't fit. I mean it is a perfect good muffler but it sticks fo much to front so it interferes with the magneto support. Pater (wackerengines) wrote me that some peolpe cut off the part of the ignition coil support and then muffler fits. But if I don't wnat to cut it off, he will replace the muffler for the smaller one. It was my fault, as I never showed him that part of my engine (and as a matter of fact it's difficult to see it on my pictures posted here). I wrote him back, that this is good option. I really like that muffler so much, that additionlly I ordered one more.

Now when I got back home I looked at the engine again and maybe he is right about cutting off this additional piece of metal. What do you think guys. It is my first conversion so any tip is more than welcome.

See the pictures below. I showed with the blue color the piece of metal I was writting about. Also blue lines show where the cut might be. The red arrow shows the pice of metal that would carry the whole load after the cut.

Help me guys. I really wanted to run this engine this weekend, but I don't want to do this without muffler.

RysiuM

RysiuM

My Feedback: (1)

Waiting for the real muffler from wackerengines I decided to mount the stock muffler. I heard it is restrictive so I opened and then I removed the internal wall. STOCK IS RESTRICTIVE. See on the picture below. Exhoust gasses must go through the hole shown on the picture. For comparison here is the exhaust port shim.
When I closed muffler back (without this internal wall) I drilled two 10mm holes in the muffler case. I didn't put any tubes - just the holes. Now my engine is ready for test run.

RysiuM

davewallace

My Feedback: (29)

Hi Rysiu,
Cutting the brace not your only option, but if you did the web in back of the coil support should give the need rigidity. Another idea is to reverse the cylinder putting the muffler on the oposite side. Also the piston would be reversed so the pinned ring would retain its orientation. The Cylinder will bolt up fine. The big issue with this idea is making that the transfer ports in the crankcase are not blocked and removing any material so the ports are a close match. I tried this on my 18cc featherlite, but didn't do it because the lower rear transfer was molded into the back plate. I am looking at my 25cc weedeater blower motor now and it will work fine with it. It would have no blockage tranfer port blockage. I would remove the center web in the top of the crankcase, because it is going the wrong way with the cylinder reversed. See my pictures below. Another bonus is that the hot exhust side of the cylinder will now be exposed to prop blast for better cooling. I didn't have to cut anyting on my 25cc to reverse the cylinder. Just remove the back plate. unbolt the cylinder. With the piston at the bottom of the stroke slip the con rod off of the crank pin and reverse the cylinder, being careful not to dislodge the piston from the cylinder. Slip the con rod over the crank pin and bolt down the cylinder. Check to insure that the transfer ports are unobstructed and the engine turns over freely. Replace the back plate. Slight trimming of the cil support wab may be required. Of course I am not resonsible for any problems that may ocurre since I am not performing the proceedure. Either way the larger muffler is better. Good luck.

Dave

RysiuM

My Feedback: (1)

I decided to run it as it is - with modified stock muffler (the inner baffle plate removed and drilled two 10mm exhaust holes). The gap between magneto wheel and ignition coil was setup using credit card.
I tried to start it by hand but no luck. The engine fired up from time to time but didn't continue to run. So I grab my Sullivan starter and the engine started after first turn. I let it run a little but when I advanced the throttle suddenly I heard a metal noise. I killed the engine and checked it out. The piece of magneto wheel was scraped. Under the vibration it just stroke the ignition coil. So even I had the original support, it still can flex under vibration. I will not weaken it even more.

I adjusted the gap using two credit cards. This time it didn't even fire then I was flipping the prop. However with starter it run after the first turn. I will not be able to start it by flipping the prop but at least my standard starter works. I can live with that.

I noticed first that the high end was way too lean. I had to unscrew it one full turn. I guess without restriction on the muffler the engine wants more fuel. After letting it warm up for 30 seconds I opened choke and run it a little.
I was able to get steady idle about 1800-2200 rpm (it is difficult to set it using flex linkage held by hand, and reading the rpm with the other).
Full throttle is 7200 rpm on Master Airscrew 16x8 Classic Series. Not bad for 1:30 with Motul oil. It my fuel I use to break in MVVS and Brison. I may get a little more rpm on 1:40 with Motul (my running mixture on MVVS and Brison).

I think these are good number for stock 25 dollars motor. The sound of the engine was also cool. It will be even better with Wacker's muffler (when I get it).

RysiuM

flipflop

How did you modify the stock carb to adjust the needles?

RysiuM

My Feedback: (1)

I didn't. I cut the plate under the needles (the original guide, that helps adjust the needles on weed whacker) as it interfered with throttle linkage. This was the only mod to the carburetor.
For adjusting needles while engine is running I made a simple tool: U-bent 7/32 aluminum tube, that the end I pressed to the mixture adjusting screws to shape the 'grabbing' part. It was not a rocket science

See pictures below of the tool and the engine. My home made test stand works OK as long as someone holds it from the back. I also show throttle linkage - easy and clean solution. Details of modified muffler and finally the magneto strike.

Enjoy
RysiuM

flipflop

Good tip on the tubing. I found a piece of brass tubing about the right size, sharpened the inside of it with an X-acto knife to get a good, snug fit, removed each needle and cut a slot in them so I could just use a screwdriver to adjust the carb.

pcjohnson_ohio

I bolted the magneto brace to the muffler to prevent flexing
Obviously this precludes changing the muffler
You can see the bolt just above the magneto bolt, just behind the sparkplug wire [link=http://www.rcuniverse.com/forum/upfiles/29406/Bw73581.jpg]Here[/link]

Pete

RysiuM

My Feedback: (1)

I thought about that, but then it would be impossible to adjust the carburator with engine running as needles are just behind the prop. With U-shaped tool I can reach the screws from behind and crown-type head allows the tool to engage at almost any angle for easy turning.

RysiuM

flipflop

Well then, just go ahead and make yourself a straight shot carb adapter like this. Very easy to tune the needles while the motor is running. This carb works very well once you can adjust the needles on it, much better than some of the single needle carbs I've seen.

RysiuM

My Feedback: (1)

I run the engine yesterday again - just for fun Also I wanted to test the technique of starting the engine.

With my little starter (standard starter that I used for all my small glow engines) I turn the engine. It has a kind of hesitation going through compression (weak starter) but then it fires up immediately. Starts at idle every time.

Than I tried how low I can get with idle. To my surprise I was able to get to the point that it sounded like an idling Harley I didn't measure the rpm but it was almost nothing. And even after idling like that for a half minute it didn't hesitate to jump full throttle. I'm really pleased with power and transition.

New mufflers from Wackerengines are on the way (I hope I will have them tomorrow) so I will take some pictures and maybe I will do some video too Because Wackerengine's muffler has exhaust tubes the engine should sound better too.

RysiuM

carlosponti

My Feedback: (1)

i am in the middle of a homelite conversion right now. i would love to see the video of your engine. also i wish that more people would show pictures of these mounted on the airplane and a video of the flight. it gives me hope my work is not in vain.

RysiuM

My Feedback: (1)

You can see the 'plane' my engine is mounted on, however it does not fly



The target plane is however about 15% done so not much to show yet. I had to finish the engine because I wanted to design and built the engine box and I wanted to be sure everything fit together. I have fuselage 80% framed and my son is at 75% of the tail part (kind of family project)

If my conversion will work the same in the air as it works now, I would always buy 'model' engines at Home Depot

RysiuM

RysiuM

My Feedback: (1)

Deleted - Double post
RysiuM

RysiuM

My Feedback: (1)

Here it is. On the first part it was running rich but after turning as H screw 1/5 turn it run up to 7300 rpm. You can see I tried to measure idle speed but still was difficult to set it steady - I measured 1800 rpm. Also I showed transition after long idling. As you can see engine didn't hesitate at all.

Also I noticed it doesn't shake like my other gasers do.

Enjoy watchng - it is about 1 minute a little over 5 MB WMV
[link=http://m.modelersinc.home.comcast.net\poulan.wmv]Poulan 25cc test video[/link]

RysiuM

KaosDriver

Congrats on your coversion! I began mine on the same engine as you began to post. I appreciate your tips. I too will be going with the Wacker muffler and was advise they have a 2" version for this engine also. I'm anxious to learn what difference in performance and sound you get. I'm like you...the gas conversions are really cool, easy to do and much cheaper to operate. I can't fabricate, but even with having to purchase the mount, muffler, and hub from Wacker, I'll have a brand new giantscale engine for under a hundred bucks and the pride of doing much of it myself. Keep up the good work!!! Mark

carlosponti

My Feedback: (1)

RysiuM nice work on the video. i liked what i saw there. like i said earlier i am in the middle of a homelite conversion and i am close to running it in the next few weeks. i am waiting for may dad to see it. he was the one who helped me turn down the fins on the magneto wheel. he is a tool and die machinist and has access to a lathe. he was intrigued by my project so i thought it fitting to let him in on the first run i have a zinger 18-8 on it already and a backplate to mount the engine i am putting together the engine stand. then it will be a matter of getting servos and receiver and put it all together for a first flight. i have had a craftsman 32 cc weedeater in my garage i dont use becuase it has problems staying running but i think it has to do with the carb adjustment. it will be my next target for conversion.

RysiuM

My Feedback: (1)

Did you? so how do you take this. I made glow plug adapter for that engine and I run it on glow. The plug was powered all the time from 2 AA 1.2V 1800mAh NiMh batteries. THE SAME FUEL: Motul oil 1:30 with gasoline 93oct (Chevron). Engine run the same like on ignition - even better. I got steady idling at 1600 rpm and 7400rpm at WOT (it is 200rpm more than I got on ignition). I didn't even adjust the needles.


If I decide to keep it like that the engine will be over 1 lb lighter (flywheel and ignition coil with support will be gone). Yes, it was hard to believe. I couldn't believe myself. But it works.

RysiuM

carlosponti

My Feedback: (1)

in essence you made a single cylinder desiel well maybe not but the concepts are the same. if i had the time i would play with that. use deisel fuel with the glow plug. i dont know even if it would have enough compresion for that but who knows. it definatley gives me hope i can get mine running and fly a 1/4 scale 10 lb plane on my homelite 25cc.

RysiuM

My Feedback: (1)

Just running on the high octane fuel and the glow plug is lid all the time. I was wondering if I can hand start it. I got luck one time. Other than that when it popped it turned one way and than back and then forth again. Just didn't have enought momentum to go through the second compression. But with starter it goes easy.

Then I checked how does it run when I cut the power from the glow plug. I rune very uneven like on self igniting from exhaust gasses. Then I connected glow again and it started to run without any hasitation again. When I cut the glow power in idling it just died.

RysiuM

av8tor1977

My Feedback: (6)

Hi,

Nice going with your experimenting. You should be able to find E-85 gasahol in your area. If you use that, you will not need the power to the glow plug all the time. Check out the thread "gas fuel with glo plug no ignition". They have been doing a lot of experimenting in that thread and there is a lot of good info. I would be interested in knowing how long your glow plug lasts if you stay with the set up you are presently running. Please let me know.

Thanks and good luck,
AV8TOR

RysiuM

My Feedback: (1)

The nearest one is in San Diego - I think.

RysiuM