Crash90

My Feedback: (17)

What muffler are you using? I get much higher RMP. I will be trying a bambula 20/8 next weekend. I will let you know what I get.
The only thing I did is I cut about 1/2" off the ends of my pitts muffler.

h82crash

It does sound like your's is off from the rest of ours. My 1.80 will turn most 18/8's at 9K. A friend's 210, about 1/2 gal through it , turns a MenzS 20x8 at about 7200 and it is on the rich side.

tonyc

My Feedback: (4)

My Moki has the Pitt's muffler with the exhaust tube ends cut off.

h82crash; My Saito 180 turned the APC 18/6 wide at over 9000 rpm. The Moki 210 turned this same prop at 7860. Now thats low.

I just took the Moki off the Ultra Hots. I will try a couple of bench runs and then send it back.

The confusing thing is that the Moki does every thing right. Easy starts, even when hot, good idle, good transition, just weak on the top end.

Hope to get to the bottom of this problem soon.

tonyc

john316

I'm hitting only about 6600 rpm on Omega 10% and the Menz 20x10 after 3 gallons but the performance in my 14 1/2 pound Patty Wagstaff Extra is breathtaking. I think I am going to give the Mejzlik 20x10 a try. TonyC, you have a sick engine on your hands judging by your numbers with the APC 18x6W, my Saito 180 turns that same prop much faster...send that engine back to the distributor.

jmw

tonyc

My Feedback: (4)

Excuse the excitement but I now have bragging rights.
Here it is.

Moki Ultra 20/10 prop 7660 rpm on no nitro fuel.

Saturday after I flew the Hots with an 18/8 Bambula prop and having weak performance, I decided to call Jim Gerard. Let me tell you he is a great guy to deal with. The short story is that I was doing every thing right, I just had a sick Moki. I told Jim I had a Moki Ultra on its way to me and I would run one more test. The Moki Ultra 20/10 is the gold standard and should hit 7600 rpm.

I was so positive that my 2.10 didn't have a chance to do this that I took the motor out of the Hots. I even took out the tank. Put the motor on a test stand and waited for the prop to come in.
Tuesday after work, the prop was in my mail box. I drilled it out, put it on the Moki and hurried to start it before the rain came.

I flipped, I flipped, I flipped, did I mention that I flipped that stupit prop for about 15 minutes without so much as a cough from the motor. I mean I was mad, I flew this motor at least 40 times and its a "starts on the first flip Moki" you know! its just not a problem to start. Well the rain came and I had to stop. Later that night it came on me. The Moki was taped for a Cline regulator and the vent was open. DUH!

Yesterday, I hooked the Cline regulator back up, flipped the prop and the motor was running. Full open on the carb, grab the tach and saw 7660. Thats the magic number that Dave Gierke talked about when he tested the Moki 2.10 for MAN. That motor was humming.

Oh by the way the Moki Ultra prop is beautiful, best looking prop I have ever seen.

So what was wrong before? Well, I don't know. My best guess is that some where I had a fuel restriction, perhaps a partial kink in the line. All I know is on the bench it did what it was suppose to do.

Love that Moki, and the Ultra prop.

tonyc

Crash90

My Feedback: (17)

Congratz. I have a bambula 20x8 that I will be trying this weekend. I also bought a digital fish scale so I can get a thrust reading. I only have about 1.5 gallons thru it and I know that it runs better every time I start it.

What size fuel tank are you guys using?

tonyc

My Feedback: (4)

Crash90

Post your numbers when you get them.
I think that 7200 is the expected # on the 20/8 Bambula.

I use a 24 oz tank, but I will be swithching to a 20 oz tank. When I get my Hots re-built.

tonyc

RollingHover

My Feedback: (1)

tonyc,

Where did you get your Moki 20x10 prop? How much? How about a pic of it?

tonyc

My Feedback: (4)

I bought the prop here on RCU. Brand new for $18 plus I paid $4 to get it shipped.

I am not yet digital so no picture. The prop looked like a piece of expensive maple furniture, the finish was that good.

I don't know if Moki props are still available. Frank Tiano no longer handles them.


tonyc

taildraggerdave

My Feedback: (1)

I'm using a 40oz. Dubro in my giant scale P-51. I usually run flat out for 13 minutes then still have time to slow it down for a few laps then land. This leaves me with 1/4 tank for emergencies......

Crash90

My Feedback: (17)

My last post was lost.

Moki 210
1.5 gallons of fuel
Byron 0%
Bambula 20/8
K&B1L Plug
Bisson Pitts Muffler with ends cut.

Cold 77-7800 rpm 18lbs thrust
Hot 75-7600 RPM 16.5lbs

Thrust was measured with Rapala 50lb digital scale. Wraped rope around tail, hooked it to the scale and throttled up.

Scale Speed

Hi Guys:

I have two Moki's and the 2.1 is definitely stronger. I am running a Moki 20-8 prop in a 1/3rd scale Pitts @ 15-1/2 lbs. and it turns 8500 on the ground using Byron 5% with 18% oil. I have unlimited vertical and can pull up out of a hover with easy. More than enough power for this airframe. My 1.8 is in a Hanger 9 Cap and what a combination. Knife-edge loops aren't a problem with a Moki 18-8 prop.

Scale Speed

john316

A couple of quick questions to the Moki experts:

1. Does higher nitro increase rpm/thrust with the normal IMAC style props used on this engine? I am running 10% nitro, have not tried lower or higher nitro to check the effects. with fuel costs what they are, I want the highest possible cost to benefit ratio.

2. Bisson lists two muflers for this engine in the Pitts style. One they call the high volume style and the other they call the low volume style. Does anyone know the difference in power output between the two???????

3. I have the low volume stlye Bisson Pitts muffler, what is gained by cutting off the muffler tips like some of you guys are talking about on this thread?

4. I have 4 gallons through this engine so far and I am taching 6660 rpm with the Menz 20x10 prop on 10% Omega fuel. You guys are getting way more rpm than I am. I'm starting to believe I got a dud or someday stuffed a shop rag in my intake. It could also be the Menz prop is less efficient. In defense of Menz and Moki, the combination is pulling my 14 1/2 pound Patty Wagstaff Extra straight up out of sight without even slowing down. Also the downline braking is awesome, it almost stops in midair when you chop throttle. Anyway, has anybody else tried the Menz on this engine, I want all the thrust I can get out of this critter.

5. Where can I get the Moki 2.1 prop everbody is talking about and how much?

jmw

RollingHover

My Feedback: (1)

John,

Strange how low your rpm's are, but at least the flying perfomance is there.

I just tach'd mine again early yesterday:

7800 rpm (needle valve slightly rich). Peak is 8,000 rpm.
Using an APC 20x8
L1 plug
5% PowerMaster Fuel
85F Air Temp
approx 69F Dew Point (before the rains came...)
Bison Pitts Style muffler

I'm not sure of the volume differences that you mention, but I'll check for you tonight.

When are you flying that plaen. I would like to see it fly. Ben

john316

Hi Ben, I flew last night over at Bandera, it's a bit tight over there but close by the house, will try to get out again at least once this week. Yea it does seem a little weird that the rpms are not there but I have no complaints on the performance. Patty will hover at just over 1/3 throttle and will pull out with authority! I'm not so sure that rpm is the only yardstick when measuring propeller performance. I mean I could wrap 20 inches of weed trimmer line around the crankshaft and it would turn up a about a gazillion rpm but the thrust would be zilch. Anyway , you get my point, the real world test is to go fly it and see how it works in the sequence. I haven't got around to the APC 20x10 yet, that is one I am going to try soon, my only concern is downline braking, there doesn't seem to be a lot of blade area out there. The Moki 20x10 and Mezjlik 20x10 are two other props I want to try, especially the Moki. Bring your Edge over some time, I haven't seen you fly that one yet.

jmw

tonyc

My Feedback: (4)

I had a chance to chat with Jim Gerard when I was trying to get my Moki 2.10 up to speed.

1)Nitro makes no difference, won't be 50 rpm difference between 0 nitro and 10% nitro. No reason at all to use it.

2)High volume pitts muffler is less restrictive, may effect the rpm by as much as 150-200rpm

3)Cutting the ends off makes a muffler less restrictive.

Thats the comments I got from Jim.

On my 2.10 I use the low volume muffler with the tips cut off, 0 nitro fuel. The Moki 20/10 Ultra prop,the Gold Standard, should hit 7500 rpm. Mine hit 7660.

I was where you are now. Low rpm and ready to ship it back. In fact I took the Moki off the Ultra Hots and gave it one more try, before it got boxed and shipped back. I knew it was a DUD so thats why I took it off the air frame. Well, surprise, when I put the Moki 20/10 prop on, and bench tested the motor it hit the exact rpm plus some.

Here is what I think is the rest of the story, so to speak. When I got the Moki, it was brand new and weak. It needed several break in runs. I did about 6 bench runs at 6000 rpm, sloppy rich. Then I put it on the Hots, might as well fly if the motor is running. I figured I would need perhaps another dozen or so flights, Well it never really got any better, No high rpm. Poor verticle with all props, Bambula being the best. When I finally gave up and called Jim I knew the motor was going back. He convinced me to give it a try with the Moki 20/10 prop. I had just bought it here on RCU but didn't have it yet. When I bench tested the prop, I used the same fuel tank from the Hots. But this time the RPM was there. I mean, first start, no adjustment to the needle valve.
My best guess is that I must have had a small kink in the fuel line. The Moki Ultra prop is light, very light, I don't know if that has any thing to do with it, I doubt it. If the Moki hits the mark with the Moki 20/10 prop, I think it will follow all the other posted numbers for prop rpm.

If your Moki is still weak, try a few no cost fixes. Cut the tips off the muffler, go to no nitro fuel, make sure the fuel line is the large tubbing all the way to the clunk, and that the clunk is drilled out.

I use a Cline. It's not needed, but I scratch build and put the tank on the CG. With the Cline I don't care where the tank is. Doesn't make a difference.

Hope this helps.

tonyc

john316

Thanks for the input tonyc, I am not sure I have an engine problem at this point. the Menz prop is the only one I have tried thus far and it may be loading the engine and restricting rpm. The engine has over 20 pounds static thrust and it has unlimited vertical plus outstanding downline braking. Now this is the Menz S 20x10. the Menz Ultra series is very similar to the Moki prop and will probably increase upline speed at the expense of downline braking. I think I am going to stay with the Menz S for now. Has anybody else tried this prop and if so, how did it perform?

jmw[:@]

michpittsman

My Feedback: (11)

My 2.10 turned 7,000 with Mach7 5%, 1/2castor-1/2 synth fuel and 20x6-10 or 20x10 Zinger or Moki prop. They are pretty; too bad they are now made of unobtanium. My Slimline pitts muffler didn't need trimming, but the exhaust port on it was about 25% SMALLER than the exhaust port on the motor. Mr. Dremel fix! With that fuel, I didn't need big fuel line; 3/32 worked fine. I'm a little tired of the gassers in my club snickering about the fuel consumption rate, but nobody can give me TWO reasons gas is better. There aren't any! Weight, power, price, radio glitching. Until you run four CASES through a 2.10, don't even say "broken in". MOKI LOVER If God had intended airplanes to have one wing, Curtis Pitts would have built them that way!

john316

Like I was saying earlier, I am more than happy with the way this prop/engine is working so I am in no big hurry to change things. I'm not too concerned about rpms unless somebody can show me another 2.1 Moki that will turn this identical prop any faster. Folks are reporting they are getting such and such rpm with various proipellers but that is like comparing oranges to apples. Nobody has tried the Menz S 20x10 on this engine out there?????

jmw

AirRayInc

My Feedback: (7)

Inspiring thread,
got a P-38 that will break in a pair of brand new 210s.
[link=http://www.airrayinc.com/vic_rc_p-38.htm]Vic RC P-38[/link]
I have access to Zinger Pros, and have 20x8s ready for initial break ins and first hops.
At the moment trying to run down a pair of J'Tec Upright/Inverted Mufflers for the engines.
I cant wait to see the performance of twin Moki 210s on an 88" P-38, with 20x8 props.

Any thoughts?

Ray

taildraggerdave

My Feedback: (1)

Are you going to maiden it at the Basin or Rabbit?? Looking forward to seeing it.
See Ya,
Dave

john316

Update on my Moki 2.1 rpm. Changed prop from Menz S 20x10 to Mezjlik 20x10 and for a whopping $45 picked up almost 500 rpm but lost performance everywhere compared to the Menz. Rpm increased from 6660 to 7060 with an increase in noise, increase in fuel flow, loss of vertical and amazingly, a loss of straight line speed. I put the Menz back on yesterday and all is well again. I have not been able to verify a loss of static thrust with instrumentation yet but an assistant that was holding my plane while performing a full throttle runup commented that that the Mezjloik didn't feel like it was pulling as hard as the Menz. This fits nicely with my theory that rpm is not an ultimate predictor of thrust and performance with a given engine/airframe combination. I thought the Mezjlik was going to give a quantum leap in performance due to percieved higher efficiency. This was obviously not the case. If you havve not tried the Menz S on your Moki yet I would give it a try.

JMW[:@]

AirRayInc

My Feedback: (7)

Hey Dave,
When I get it all set, I will be taking it to Rabbit. At present rate and income, about the first weekend of December looks to be the target date.

+++++++++

Have any of you tried a Menz Ultra, if so what sizes and tach numbers did you get.

Ray

Major catastrophe

My Feedback: (9)

OK i have read every ones post and it all looks good but I have a few question. One is for Tonyc , did you feel like the 2.1 is still a lesser engine then the 1.80 or did you get your 2.10 working better then your 1.8?
I want one of the moki's and would like to buy one 1.8 or the 2.1. I read about people and the 2.1 pulling 18-20 LB thrust and not what it should have been 25lb of thrust.

And what im hearing is the 1.8 Vs power, fuel comsupstion, and weight. Out runs the 2.1 . I would like to hear some feed back from this.
my email address is [email protected]
or reply to this post

tonyc

My Feedback: (4)

Major catastrophe ;

I did get my Moki 2.10 running right. I put the Moki 20/10 Ultra prop on this motor and it hit 7660 rpm. This is the tach reading that Model Airplane News said was 26 lbs of thrust.

So the next question is how does it compare to the Moki 180? Stronger, yes its stronger, heavier we know it is by a few ounces, burns more fuel, well we know it must because its bigger motor.

How does it start and run? Great, just like the 180.

If I was going to buy a brand new motor and pay top dollar what would I buy, it would be the 2.10. If I saw a deal on a 180, no question about it I would grab it.

My rule of thumb for a sport plane that weighs in at 14 lbs or less put the 180 on it. Above that I would put the 2.10 on it.

I would not be concerned at fuel consumption. The 0% no nitro fuel is cheap, about 1/2 the cost of 15% fuel. The motors are both so powerful that most of the time I don't need the top end of the rpm curve.

Hope this helps

tonyc