My first Moki
 

Ok, after reading all the great posts on Moki's I picked one up for my CMP Extra 72". I am running some 5% fai fuel in it and ran about four 24oz tanks on the stand before mounting. I tapped the back and mounted a perry vp-30 and tuned it up. Weighing in at about 13.5lbs and running a Bambula 18x8 wood prop I expected this thing to skyrocket. I am still running a bit rich on the highend but probably only about 5 clicks or to drop about 400 from peak. Well even with the pump there appears to be a change in the ratio as mid flight I am definately blowing less smoke and what is noticably rich at the start is probably right on at mid flight. Not sure why that is happening. I do have a pressure bypass system with a T fitting between the pump and the carb with the bypass going back to the tank. I put a zip tie around the bypass to shrink the whole some but fuel can definately flow back through it. The tank is on the cg which is about 8 inches back from its original location. Anyway to make a long story short its not as impressive as I would have thought. I had a GP Giles of the same size and weight with at ST 2300 1.4ci running a 17x6 APC that would pull the plane out of sight. This Moki setup can just barely pull out of a hover. My first impression is that the Bambula 18x8 (although being a wide blade) is not the right prop (at least here in Illinois). I have always been dissapointed when trying wood props and always had a noticable difference in power when going with a APC. I am thinking about either my 17x8 APC or the 18X6 Wide APC. I am using a O.S. F plug on the engine. I have a feeling either my pump setup isn't perfect, wrong prop, or something tired about this engine. I did buy as "New" on ebay and indeed the engine had no castor stains on it and the sleeve looked like it had never been run but when I received it the engine was locked. I had to pull it apart to find the crank had rust on it and I had to oven heat it to free up the bearings and then oil it all down. Sleeve all looked new though so I don't know if its possible that it was just old but new or if someone bench ran it, didn't oil it up, and put it away. Brand new compression though. Anyway if anyone has some advice or tricks for these I would love to hear it.

RE: My first Moki
 

First thing you should do is take that piece-o-junk Perry pump off and toss it in the trash.

Buy a Cline Regulator and install it.

http://www.billsroom.com/pcfs/

Tune your low end for perfect transition. It takes time to get it set perfect, but you can do it if you just put the time into it.

Tune your high end for best running and back it up about 3 clicks.

You asked. :)

RE: My first Moki
 

I had a feeling the perry was going to get a response. I appreciate it and will look into the cline. Looking at the diagram:

http://www.billsroom.com/pcfs/produc...g/Pcfs1t1e.gif

In this setup are the overflow and fill lines supposed to be plugged during flight? And if so what keeps the crankcase pressure from exceeding what the tank can take? Being that it is pressurized do you have to worry about the fuel tubing pushing itself off the nipples on the tank? Why do they say its a unique one way check valve? I assume the regulator is the PCFS in the diagram. It seems like this is a relatively plug and play system. I don't see any knobs to turn or adjust. Is that the case?

RE: My first Moki
 

Which size Moki are you talking about?

RE: My first Moki
 

Mounting the Cline is a lot easier than it looks. Very simple.

You already have the backplate of the engine tapped. You need to run a fuel line from the backplate up to the vent line in your tank. But, before you hook it up--Cline gives you a 1-way check valve to use. You take that check valve and stuff it up in the line about 3/4" and then you stick the line on the nipple you have mounted in the backplate. You want the check valve mounted as close to the engine as humanly possible. 1" or less.

Now that will take the crankcase pulses and presasurize the tank. The check valve will prevent the pressure from coming back out. So, now you got a pressurized tank. I use DuBro tanks and have never had one split out. If you want a bulletproof tank--get a Kavan. I've had a Sullivan slant tank blow it's guts all over the inside of a plane just from muffler pressure. I don't use those anymore.

Okay---pressurized tank. Mount the Cline regulator on about 1" of fuel tubing and plug it into the inlet nipple on the carb. I've done more than a few Clines (about a dozen) and I think it works better if you DON'T use a remote needle valve. Leave the needle on the carb and plug the Cline right into the fuel inlet nipple on the carb. The Cline should be 1" or less from your needle valve.

Now the other side of the Cline gets plumbed to the clunk on the tank.

You will installt a T fitting in both the pressure line and the clunk line. Run a short piece of tubing on each of them and mount them so you can get access to them without removing the cowl.

How it works:
The engine pressurizes the tank. That forces fuel up to the Cline and provides constant and positive fuel flow to the Cline at all times. The Cline has a diaphram inside and a couple valves. It senses the vacuum of the carb every time the crankshaft rotates and opens the hole under the carb. It lets in the fuel as the engine demands it. No more--no less.

You hook it up and pressure test the system. Use wire ties or clamps on everything to keep from blowing the lines off.

Start the engine and let it idle for a few seconds to build tank pressure. Rev it slowly to build all the tank pressure it will ever have. You need to do all your tuning with the tank fully pressureized. It won't get fully pressurized untill you rev it up to full power and hold it for a couple seconds.

NOW you can tune it. Run it up to full throttle and adjust it for max RPM. Back it off about 3 or 4 clicks.

Now adjust the low end. Just set your low end for perfection. It should idle for a whole tank without loading up. The Cline will not allow it to flood the engine because if you adjusted it right--it only lets the engine suck in the fuel it needs.

I've actually mounted 2-stroke glow engines upside down with the tank on the CG. Install a Cline, adjust your carb and it will run flawlessly without any on-board glow or fancy hot plugs. They just RUN.

To fuel it:
Take both plugs out of the TEE lines. Plug your pump into the clunk line and fuel it untill the fuel comes out the pressure line. Same as a regular glow setup. Fill through the clunk--it's full when it comes out the tank pressure line.

Plug both lines. Go fly.

When your done flying:
Pull the plug from the pressure line and let all the pressure blow off. You'll know you pulled off the clunk line if it squirts out a bunch of glow fuel. [sm=tongue_smile.gif]

Worth every penny IMO.

RE: My first Moki
 

If you have the 135 a 18x8 is a bit much prop, I have a older that is marked as a 120 but I believe the previous owner had it converted to the 135 and I've used a 16x8 with good results in a Hanger9 73" Cap and it moves fast with a good smoke trail but I forget what tach readings I got .

Dauntae

RE: My first Moki
 

Doh, Can't believe I didn't state the size. This is a Moki 180 with a bisson pitts muffler. Thats why I figured with the same weight as my 140 I was going to be blown away! :^) Not yet though.

Rcpilet
Thanks for the explanation. Going to order one and give it a go.

RE: My first Moki
 

Moki 180 should easily swing an 18-8 or a 19-8 or even a 20-6 Zinger in the 7000RPM range.

I didn't read your first post close enough. I missed the part about the Bambula. [:'(] Those are good for stirring paint, rowing boats, and spreading epoxy. Not much good for props. They are just too darn fat. You'll end up with a 16-8 Bambula if you want to get any RPM outta that Moki. Junk that prop.

My opinion is that the APC props make a lot of noise and turn a lot of RPM, but they don't deliver when it comes to putting out the thrust.

I'd do this if it was me. Actually, I've already done this. Years ago before I stopped flying big glow engines. ;) Get a MenzS 18-10 or Master Airscrew wood Schimitar 19-8 and try that.

Here:
The Master Airscrew 19-8
http://www2.towerhobbies.com/cgi-bin...?&I=LXAPX3&P=0

The MA Schimitar will put out good thrust and let the engine turn up in the RPM range you need to make good power on 5% fuel or FAI fuel.

Or go here and click on Menz Standard wood props and get an 18-10 or a 19-8. They even make a 20-6 which would put out a truckload of thrust if your engine will turn it. I think it will. I never ran the 20-6 prop on my Moki 180, but I did run it on a ST3000 (also a 180) and it was cranking along at 7200RPM. The Moki should swing it.

http://www.aircraftinternational.com/

I know props are expensive. But, if you get that Cline set up and get the engine tuned--it will easily turn anything from an 18-10 up to a 20-6. Try some different props. Those Bambula props are junk. Shoot--try a Pro Zinger!! Those are better than a Bambula. [8D] I think your gonna be a happy camper once you install the Cline and try a few different props.

Sound off if you need help with the Cline. Myself or someone else can help you set it up if you have trouble. I don't think you will. It's pretty simple to install. You'll have to open your needles a little more than if it didn't have a Cline, but don't worry. Just put the Cline on and tune it to run the best. Take your time on the low end and really tweak on it untill you have it adjusted perfect. With the engine being new--it may take a few more tanks before she will settle down and hold a nice idle. You can run it just the tinniest little bit rich if you need to, but don't be lazy and forget about it. You can tweak the engine in just perfect with a Cline and she'll tick over like a Swiss watch.

Hope this helps.

RE: My first Moki
 

-------------

***Are we talking about a 1.35, a 1.80 or a 2.10 here? I'm assuming a 1.80 - just a guess.

Mokis are made from good metal. Good metal takes a while to wear in.

Personally, I prefer the Cline or Iron Bay regulator set up. Adjustment free with great results. Truthfully, I don't think the Perry Pump is the problem from your description. The engine isn't broken-in yet, that's all.

RE: My first Moki
 

Thanks for all the great advise. The engine will idle all day long with no problems and so far the only deadstick I have had was when the throttle arm nut wiggled loose and the barrel stuck shut. :^) Hey at least it was a regular deadstick instead of a full power until the fuel runs out and then deadstick! Ha ha. I think the engine just isn't turning up. I'll start with a few props and get a cline once my airplane fund recovers. I know on my ST2300 it ran like crap when propped with a 18x6 wide at around 7300 rpm and then went to a 17x6 regular and it was screaming at 9K. Tons more power! I see alot of posts about many of the big two strokes being "luggers" and so far I am not convinced. Two stroke gas engine maybe. But so far I have found two stroke glows are just like the smaller engines they like the rpm. Seems like 7k anything is too slow. 8k or higher seems to be the sweet spot. I'll shoot for that.

BTW:
Does bambula make good firewood? :^)

RE: My first Moki
 

The muffler that comes with all the glowengines is far more restrictive than the ones that comes with the gas engines because gas engines have a pump and dont need any muffler pressure. This quiet muffler that comes with most common glow engines OS,ST.... robs a whole lot of power atleast 500rpm compared to a free flowing muffler similar to the ones that comes with a gasoline engine. If you use a pump on any twostroke glow engine and use a free flowing muffler/ cannister or quiet pipe then you can run any prop size you wish. 6500-7000 peak rpm is no problem for a pumped 30cc glow engine.

My G3250 on a quiet pipe turns a APC 20x12, 20x8W or 22x8 @ +7500rpm.

RE: My first Moki
 

Just ordered my cline setup from the above link. That was the easiest, most friendly, personalized service I have had with a product! Gentleman on the phone offered (I didn't have to ask) lots of helpful advice and gave some great setup tips as well. Informed me that some moki carbs may need to be lathed to richen up enough and that he provides that service if necessary. I think mine will be fine though as with my perry setup it will drown the moki if I let it. I think I might be a factor in the problem too as even with the perry I back off the needle some from max and his advice it to run it up to just about max and leave the highend alone. Since its pumped / presurised you don't have to worry about it going lean. Maybe if I get some time I'll run a rpm test of perry vs cline. Either way I like the idea of not having to monkey with another screw like on the perry.

Anyway. Great service so far from Cline and Associates!!:D

RE: My first Moki
 

Your gonna be smiling so big the corners of your mouth will touch behind your ears, once you put that Cline on. :D

My ST3000 was ported and designed to develope peak HP at 7900RPM. Thats why I proppped it for about 7200RPM on the bench. I don't know where the peak HP is for the Moki 180. I always tried to prop for 7300--7500RPM. It will unload in the air to a little over 8000RPM and be right in the sweet spot. I imagine you could push it to 8500RPM on the bench, but your prop is going to have to be smaller in order to get those RPM. You'll make more thurst with a large diameter prop around 7500RPM than a little 17-10 twisting up close to 9000RPM.

Big thrust forumla:
Large diameter--low pitch
19-8, 20-6

Speed forumula:
Little diameter--higher pitch
18-10, 17-10

It's all about the same load factor, and the engine should turn the same RPM or very close with an 18-10, 19-8 or a 20-6 prop. But, you'll get 5 or 7 pounds more thrust from the 20-6 at 7400RPM than the 18-10 at 8800RPM. RPM is not everything. It's thrust that you want on an aerobatic plane. I wouldn't lug it under 7000RPM, but I also wouldn't prop it for 8000RPM either. Somewhere in the middle is where I'd prop it.