31.7 oz. I still have a little "fat" to trim off. This weight is complete as you see with no hall sensor/magnet. Waiting for LiPo batteries and regulators.

The Echo is definitely on a diet! Looking nice. Have you finalized the aft end of crank and seal or end plug? Curious how that was resolved.

You could get rid of that big spark plug....use a aluminum screw in apater and the smallest spark plug you can find. Thanks Capt,n

at first i thought that you must be including the ignition in this figure but then i went back through the thread and did the math. now that i've started converting a kawasaki 25cc your weight seems heavy.

here's a list of the kawasaki's parts compared to yours. the cylinder is untouched, the crank only has the rear shaft cut off at the bearing and the case halves only have the mag housing and some unneeded lugs cut off. i might be able to lose an oz or two if i go nuts with the dremel

............................................echo.. ..............kawasaki

crank+rod+piston....................9 oz..................7 oz

bare cylinder..........................7.75 oz...............6 oz

case halves+bearings.............7.7 oz.................6 oz

so if i use your techniques on the carb, carb adapter, muffler, hub, Ti bolts and CM-6 plug i should come in under 26 oz!! COOL!!


dave

Mikenlapaz,

I'm still wanting to put the ignition sensor in the rear. I'm waiting for some thin wall tubing that's the same diameter as the crank. I'm going to decrease the diameter of the rear crank behind the rear bearing and cut it off about 3/8" out of the bearing. Then I'll slide the tube over and that will go throught the rear seal and I can solder on a magnet plate to the back of the tubing after it comes out of the seal. That way I can mount the hall sensor on an arm and have it linked to the throttle for advance.

captn,

I would like to use one of the 1/4 X 20 spark plugs but they are almost $15 each and I've heard they don't last long. This I feel was a good compromise at $2.25 per.

ZAGNUT,

Holly cow!!!!!!!! That's light!!! Do you have a model # and/or pic? I'd love to do this surgery to that motor. Keep us posted. The reason I'm not including the ignition in the weight is that the ignition will be mounted over the wing so it won't affect the balance. The only thing forward will be the sensor/wire and plug boot.

Doug

here's an [link=http://www.rcuniverse.com/forum/Engine_experts%2C_what_is_it_%3F/m_1531278/tm.htm]old thread[/link] with some pics. it seems that the newer engines have a shorter stroke than mine and are about 22cc. in the pics you can see the clutch housing still bolted to the four nipples/lugs that i'll be using to mount the engine to the firewall. i've seen quite a few of these exact same engines on hedge trimmers of various names, mine was on a "golden-star".


dave

Where is the engine? plane?

I see this engine. But no plane? I would also like to see the very latest photos of them! Hey RCIGN have you ever converted that same engine? Looks like Zagnut has a good one there. Take Care & have fun!!!!

Hey y'all,

Sorry for the delay. I got a new job/promotion at work and have been in training out of town for most of April. I'm back now. The engine is complete minus the ignition. I've been having problems with it and may have to use a larger(standard) size resistor plug. I have a brand new Kokam 7.4v 1500 mah LiPo battery, a 6.0v regulator, and a voltage monitor. All the radio gear is installed. Just waiting on ignition. After that's working, I'll put the engine on a test stand and fine tune it and then it's a go.

Stay tuned...

Doug

7.4v, 1500 mah LiPo next to a 4.8v, 600 mah NiCd

What's with the advertising right between posts?

Anyway, here is the billet shielded plug cap from C&H. Pretty cool. I'm going to get the Echo running tonight on the stand.

Very Nice Job Doug T
I ´ve benn following your posts all the time.
I try to use a brand new pro spark i storaged for 3 years in my shop. Now bolted in a ryobi and in a new sukhoi 72"WS went to the field, the system was Ok and the spark at home was big and blue, once at the field I connected the battery, fueled the engine and the spark gone away, it never spark again.
I don´t know what could happen, if the coil blew up, the hall sensor suffered something in the surface, the circuitry failed..I don´t know what could happen, from one moment to another, without use...it just died.

In scratch built ignition formums a lot of guys told me that the tim 6 is not suitable for our gassers and they have a lot of troubles with the coils..how are you dealing with that???

Hope you can tell.

Rodolfo.

Tato,

In the "scratch built ignition" thread I posted that I don't think the TIM-6 ignition is very well suited for RC gas engines. I'm going to use nothing but CDI ignitions or stock flywheel ignitions in the future. It may cost more initially, but buying new coils, transistors, and the time and stress of waiting for shipment make it worth it for me. I'd love to see a "cheap" alternative that could be built by the average modeler.

Doug

Did this end? i wanted to know how this ends or atleast flys

Doug, How goes this project ? We're needing an update. Many of us are following your progress.

No, the journey hasn't ended. My new job has me commuting 2 hours a day and lots of OT(2X pay!!!!). And my wife works full time and is going to school 1/2 time. And I moved and now use a mini-storage(with electricity) as my shop that is 2 miles away. These all really cut into the hobby time. [&o]

Worked on it yesterday for a couple hours. It's all complete and I'm going to time the ignition this week and test run it by this weekend. It's all up engine weight is 31.5 oz. I'll be posting some pix soon.

Thanks for the interest.

Doug

I mounted the engine tonight. 32 oz. with the larger, resistor plug. Now I'm working on the timing and fuel setup.

I'd like to run a 14-6 or 15-6 three bladed prop. Any suggestions?

Two blades are more efficient.... and lighter. APC props work the best by far for me.

AV8TOR

How did it run? The engine looks actually kinda small.

I finally had time to run the Echo last night. Had a problem with the carb so I swapped in a "stock" Walbro of the same size. With the ignition fixed at 12-13 degrees advance I could get a decent idle and 6300 rpm on a zinger 14-8. I'll try to get more advance and find a happy compromise of idle/top end.

You're right, this is a small motor.

I was test running it with a 1 oz fuel tank and got 4-5 minutes of fiddling with carb needle settings and running it up and then idling. I'm thinking a 4-6 oz tank will be enough.

You will find that it likes 25 to 28 degrees of advance for best power.

You can set that and not worry about kicking back on starting with these small and low compression motors.

Good luck,
AV8TOR

I'm having problems setting the high and low needles. I think there is a base gasket leak that throws everything off. I can set it to idle well and the top end suffers or I can set it for power and it won't idle. I'll try to fix it tomorrow and report.

Also, I'm going to run a Zinger 15-6. Hope to have the plane flying by next weekend.

I have seen this happen if the metering diaphragm gets old and too stiff. You can't get it rich enough at top end unless the idle mixture screw is opened up too much, then it's way too rich at idle. Check for air leaks for sure, but you might need to rebuild the carb. You also want a lot more advance than 12 degrees. 28 degrees seems to be almost universally correct with these small engines, though my modified 23.6cc engine likes a little less at 25. The BME website (www.bmeengine.com/html/manual.htm) has a great section on setting up these gas motors.

Good luck,
AV8TOR

Thanks av8tor,

On the last runs I made a new sensor bracket so I could get 25 degrees advance and that is what I probably will run. I will do as you mentioned and replace all the gaskets and diaphrams in the carb. Can't hurt.

What sort of top end and idle rpm should I expect from this motor? I'm thinking either a 14-8 or 15-6 Zinger. I'd love to find a fun-fly style prop(APC W series) in the 14-15" range but am having difficulties.

Doug

Me again....
After looking more closely at your pics, I see that the vent hole in the carb cover is directly exposed to the prop blast. This could also cause a problem. (Sometimes it does, sometimes not.) The BME site covers this as well.

AV8TOR

I get about 8000 rpm's with an APC 16 x 8 prop with my modified 23.6cc Echo/Kioritz, here at 4000 ft. altitude and 80 to 90 degrees temp. It's kind of a trick little motor with a lot of mods. You should see 7000+ if not more with a 15 x 8 APC depending on your density altitude. It is often hard to find the APC prop you want at the hobby stores. They carry a limited supply because they are expensive I guess. I ordered mine from Tower Hobbies. They are considerably better than the other common props though, and are worth searching out if you want good performance. Probably because of the fixed timing we use on these little guys, I never can seem to get a reliable idle below around 2000 rpm.

Keep us posted and good luck,
AV8TOR