rport

My Feedback: (27)

I have a fairly new ZDZ 100 ng on an Aviation Models 35% Yak. I can't seem to get much power out of the engine; it just flies the plane/ no great power. The engine only produces aprox 6,000 rpm with a 26/10 bambula. Numerous attempts have been made to tune it with more rpms to no avail. One time it ran 6150 rpms, but was too lean. It seems to be running cool enough with the cowl on( 220 degrees or less). Oil is synthetic at 40:1 mixture. Exhaust system is JMB cannisters with headers. I am going to try putting the stock mufflers back on and checking the performance. This engine was sent to you around 3-4 weeks ago with a noise. The technician stated that everything was ok and ran it on the test stand with a 26/10 prop at 6400 rpms. He also indicated that the noise was the wrist pin bearing and would not be a problem. I need to get more power out of this engine to fly my 30 pound airplane. Also, when rich enough, the engine will start ok/transition ok. When the engine is lean, it will be difficult to start. The needles seem to adjust the mixture without problem. I did not adjust the timing since coming back from your shop. I assumed that the technician had adjusted it and was happy with its' setting. This is not a black head or blue head, just gray. I either need some adjustment or a more powerful engine.

Ron

Mike Dooley/RCS

Ron,
What size JMB cans are you using?
How long are your header pipes? Did you cut them down?
Let me know.

Mike Dooley/RCS

Ron, Is it a 100NG? Or just the older style 100B2? If it is the older style 100B2, power is fine. You may go to a 24x10 to get the rpm up, but ist should be fine if it is the older 100B2 and NOT the 100NG.
Thanks,

rport

My Feedback: (27)

Mike,
It says on the engine that it is a 100 B2 NG. The cannisters are JMB 80/70/300. I did cut down the headers at the 90 degree bend ( approx 5/8 inch section) to get them to fit with the tunnel in the airplane.

Ron

rport

My Feedback: (27)

Mike,
The actual length of the header pipes as they come to me from you were not adjusted.

Ron

wingburner

My Feedback: (17)

Hi Ron.....I have owned a ZDZ 100NG for 3 years and it's on a Carden 35% 330s...The plane weighs 33lbs.....I've tried many many props and the best I have found is a Mejzlik 26\10...It turns it at 6500....A PT Models Carbon prop is also very similar and may spin a little easier....You are on the right track with wanting the RPM up as they don't perform well at lower RPMS or at least in my case.

The engine performs very well with the heavy Carden...It has unlimited vertical but is slows as altitude increases and pull outs-out of hovering is slow......I find for the weight the engine is very strong...I know you probably don't want to spend big bucks on another prop but you will be rewarded greatly with the performance of the Mejzlik..

I am running I believe around a 11 or 12" header with KS canisters...If your trying to compete with the other 100cc engines it won't do it but it is a fantastic engine anyway,just keep the RPMs up...I see they claim they got 6450 at the factory which is excellent...Maybe they can tell you which prop they used and exhaust...Maybe it was open exhaust??

rport

My Feedback: (27)

Wingburner, thanks for the response. At present, i am using a Mejzlik 27/10, but also have a Mejzlik 26/10. In order to get the rpm's up, i had to remove the cannisters and go back to the standard mufflers. With this setup i was getting 6800 with the 26/10. So then i went to the 27/10 on advice from a fellow club member. The plane seems to fly well with this arrangement and exhibits good flight characteristics, considering the size and weight of the airplane. I am going to stay with this setup for a while to see if it gets any better. Like your engine, this one has not seen much fuel. I am hoping after 2-4 gallons, that it will develop some more power. I believe that it just needs to be flown for a while. Early on, i was discouraged when it wouldn't perform well. I expected to purchase another more powerful engine, such as a 3W,etc. I understand that they run very well.

Ron