SunDevilPilot

Zenoah G-20

SunDevilPilot

Zenoah G-20 EI

fishkillbill

My Feedback: (4)

I just started with a couple of gas motors. So far, I haven't adjusted them yet. I just run them as they came. I would like some "hand holding" just in case I need to some time. Your instructions are:

1. Set high needle for max performance minus a few hundred RPM.
2. Then start motor and go full throttle and slowly reduce throttle while listening for the motor to 4-stroke.
3. As the motor transitions from the properly set high needle down onto the low speed needle, which is likely rich at a stock setting, the motor will go from a nice 2 stroke to a 4 stroke as it begins to misfire.
4. Shut the motor off and lean the low slightly, maybe a 1/16th at a time if not less.

How do I do step on before I start the motor?

Bill

Navy0968

I just finished my H9 Super Cub conversion and thought I would share a few photos. I decided to use a Fuji Imac BT 24 ei engine because it fits so great inside the cowl. The mods include an aluminum firewall, Fiberglass Specialties super cub cowl with added detail (to include working doors), flaps, functional scale landing light, Dubro 6" tires, etc. The Super Cub cowl provides gobs of interior room and affords excellent cooling. It also allows the fuel dot to be mounted on the firewall and installation of a manual choke rod which can be operated with the cowl doors closed. All in all I think it is a sweet setup.

SunDevilPilot

When I first started I used a tach. Now I just listen to the motor for the initial adjustment. Then, once I have the motor close I fly it. While in flight you can hear the motor "Bark" or misfire at you, this indicates rich. Fly full throttle and put the plane into a steep climb. A lean motor will start to slow down and sag. A properly adjusted motor will hold it's full throttle RPM while in a vertical climb. The low end needle is adjusted by listening for the 4 stroking while on the ground and transitioning from full throttle to idle and vice versa.

Here is a link describing all the info you could ever need to know about walbro carbs. There is a tuning section which talks about the same method I use.

http://tech.flygsw.org/walbro_tuneup.htm

SunDevilPilot

SunDevilPilot

Here is my current project, a Sig 1/4 Cub converted to a PA-18, powered by a Zenoah G-26EI. Trust me, this plane is a lot of work to build and I would not fly it with a Zenoah motor if I was not totally confident in their motors. I could have chosen any motor but for reliability Zenoah is one of the best. I actually find the Zenoah's a little more consistent than my DA-50.

SunDevilPilot

SunDevilPilot

Firewall has been setup for the Zenoah and would be a real mess to adjust for a different brand....That is how confident I am in the motor.

SunDevilPilot

Planejaw

My Feedback: (53)

Tex,

Sorry to hear about your Cub. I'm glad that it's going to be repairable.

I was able to get about a dozen flights on mine since last Friday. I'm still not 100% convinced of the idle characteristics of the 20 ei engine. Even with a new plug, she seems to come down and idle somewhat high, then drops down...and that's with quite a few tankfuls of gas just getting the needles as close as they are. I know that Zenoah's are good engines, but from my gas experience, you can't beat the DLE's and DA's. DLE is supposed to come out with a 20 gasser this fall...I'm going to put one of those in my Cub, or just opt for a DL-30...one way or another.

I've always liked and have quite a few Saito engines, from a 40 all the way up to a 150. The 150 is almost new, only had it in a Spacewalker for a short time, then pulled it out and boxed it up. I didn't like the way the Spacewalker flew. The Saito 150 is a Golden Knight version. Let me know if you need an engine.

boydboy

My Feedback: (3)

Navy, Sweet job on the Super cub! do you have a pict of where the fuel dot is?

Navy0968

Boydboy, the fuel dot is located above the fuel line to the carb. I pulled the cowl off and shot a couple photos to show the location of the fuel dot and manual choke rod.

Jim

vetter63

Hey John,
I've been following with interest the discussion on idling characteristics of the G20 on the H9 Cub. On my Cub, I traced the problem to not having sufficient throw on the throttle linkage on the engine. The problem I was having was the idle setting was not consistent. One time it would settle on low idle , the next time on higher idle. What I did is fabricate about a 3/4 inch arm which attached to the existing throttle arm. What that gave me is more resolution on the engine end with small servo movements. Guess what? The idle setting is now totally consistent. It sure worked for me.

Vetter63

[]TEX[]

I had a feeling the throttle linkage was a problem as well.

Planejaw

My Feedback: (53)

Great idea Vetter!

A couple times I've looked at the existing linkage and wondered if I should retro-fit it. I've used longer aluminum throttle arms on Fujis, that I purchased from PSP engineering. I agree that the longer arms give better geometry and allow you to use more throw and less "limited" travel on your servos, helping to give a little more "linearity" to the throttle control.

You've convinced me to change mine!! Thanks.

Thought I'd throw in a photo or two from this past weekend. One shows the "one-wheel" touch and goes, flying down the runway on one tire, then you roll to the other direction and roll down the runway on the other, then hit the gas and takeoff again. If you can't do too many aerobatics in the air when flying a Cub, try some variations in your takeoffs and landings!

boydboy

My Feedback: (3)

Navy, Thanks for the extra picts. That is really slick. The aluminum on the firewall really dresses things up as well. Keep ip the good work. [sm=thumbs_up.gif]

[]TEX[]

Got all the parts and I guess the crash came at the best time. I have spent the last two weeks moving and unpacking.

Much rather be flying...[]

Planejaw

My Feedback: (53)

Great to hear you received your parts to rebuild your Cub.

Are you going to keep the Zenoah in it, or are you thinking of changing to a 4-stroke?

[]TEX[]

I'd be interested in the 150, PM me to discuss.

jaless

H9 1/4 scale Cubs at HH are now back in stock. I just ordered mine. I will use this site for lots of great information while building and flying. Already like the idea of the 6" wheels and O-rings.

Thanks Guys!

ewalds

jaless>> When doyou get it?? Is it the arf?? I´m just waiting for mine just about now

Planejaw

My Feedback: (53)

Jaless,

Great to hear you're joining the "Cub" fraternity.

I think everyone will agree that you'll love flying it, whether you purchased the plug-and-play or ARF versions. Almost everyone's had a Cub, and those that haven't, it's just a matter of time!!

Keep us posted on your assembly and flying.

roaddog2

PlaneJaw's right! I've got one an' I can't even fly yet!
:O)
RD

[]TEX[]

They are out of stock already? WOW!

[]TEX[]

After about 90 minutes of trimming, I finally got the new cowl fitted. What a PITA that is, especially if you are a perfectionist!

New windscreen applied as well and reworked the throttle linkage for a more even throw at idle. Installed a Xoar prop to finish it off.

Some minor repairs to the wings and I'll be ready for the weekend. Who would have thought that nylon snaps screws that hold on the wing don't snap in a crash.

Planejaw

My Feedback: (53)

Amen on the cowl trimming. I replaced mine a couple weeks ago. It was getting a little ragged and the cowl mounting screw-holes were starting to enlarge from vibration. I picked up the Du-Bro E/Z Mount Cowl System (.20 to .90 size), which uses special rubber washers to isolate the screws from any part of the fiberglass cowl. At $10 per kit (there's also a larger size available) it isn't real cheap, but sure saves on having to replace cowls. As for cutting the cowl, this one is a PITA, but well worth it when it fits back on like a glove. The interesting part was under-cutting the area around the underside of the cylinders, but it worked out very well. Found some new carbide, barrel-shaped cutting bits for the Dremel...works great and will probably never wear out.

I'm like you Tex, need to be sure that it looks and fits as close to perfect as possible!! I take a lot of pride in my aircraft! As I'm putting my aircraft together at the field, I'm tugging on control surfaces (checking hinges), checking the security of control horns, clevices, ball links, bolts, hatch screws, etc. So far, I've never had a mechanical failure in flight, and that goes back to control-line and early RC starting in 1968. My father was an engineer and taught me well. The worst I've had was a loose muffler bolt and a couple of hatch screws that vibrated loose during a flight. Unfortunately, those are the hazards of flying any airplane, particularly gassers and all of the vibrations they generate...no matter how carefully you build and maintain them! In addition, having kept flight logs since 1986 help to keep a records of the good, the bad and the (thankfully rare), ugly.

Let me know some more detail on your throttle linkage or take some photos the next time the cowl is off...I think I'm going to re-work mine when flying season ends, trying to get a little better low-throttle control, reducing the sensitivity between idle and half-throttle. I'm finishing up a Sig Morrisey Bravo and Concept Models Fleet Biplane this fall and winter. May try to fit in an Aeroworks Sport Cub (red/white) if time permits, so the H-9 Cub will fit into that schedule somewhere, as will any minor repairs to anything else in the fleet. Should be no problem, it's a long six-month winter in Michigan!

When I bought my Cub from the LHS, it had a cracked windshield. The first one that HH sent us was also cracked, as were the next 7 they sent!! Finally, after the LHS called them and asked them to inspect the windshields before they sent them, we did find 4 undamaged ones...maybe the last ones in existence...and I bought them all!! Anyway, the one that I put on cracked soon afterward, but I still have 3 brand new ones left...probably replace the current cracked one this winter as well. It's a long six month winter in Michigan.

Let me know how you like the Xoar prop. 16X6 or 16X8? If you've got a tachometer, let me know what your idle and high-end are at and I'll also check mine. Hope your G20 behaves better for you.

[]TEX[]

I got the 16-6, I'll keep ya posted. I am on the third windscreen, HH replaced the first two which promptly cracked after a few flights. Thus third one arrived cracked, but it was in an area where a lot of glue is required and it was an arc so no where for it to spread out. I installed it anyway.

I will post pics tonight of the throttle. I had to go to 75/75(don't like going below 80) on end points, but travel is linear.