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MOKI RADIAL Care and Maintenence

Old 12-15-2013, 02:52 PM
  #2726  
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Already some very good info to you here, bossrc. All I can add, is the fact that mine ran perfectly for 60+ flights without the need for a external fuel pump. I strongly recommend that you measure the temp on each of the cylinders after every flight, to make sure you don't miss a non working cylinder. Good luck with your fantastic motor! :-)
Old 12-15-2013, 06:11 PM
  #2727  
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I really appreciate the response and inputs to my questions. I'm making my way through this thread....what a wealth of information. As a first time Moki and Radial owner, these are very helpful. May save an airplane. I picked up an infrared temp scanner this weekend. Gotta love Harbor Freight. I hope to run the engine later this week and get the Nieuport 28 in the air in time for the Blue Max in January. Thanks guys.
Dennis
Old 12-19-2013, 03:59 AM
  #2728  
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Originally Posted by ram3500-RCU
Yes, I am running the new unit and it does not need a regulator, and accepts up to 10v input. I run a 2 cell LiPo on it, at 7.4 volts with good results.

It is plug and play as a replacement for the original unit.

I have (2) original "top hat" units for sale if anyone is interested. One is new and never flown, the second has light use on it. PM me if interested.
HI Gary
Have just fitted the new ignition to my 250 not started as yet 1 SOLID GREEN 1 BLINKING reason on the blink did read somewhere can,t remember why
Old 12-19-2013, 04:41 AM
  #2729  
nine o nine
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The solid light means power is on and the blink occurs when spark is made. Mitch
Old 12-24-2013, 01:35 PM
  #2730  
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Does anybody know what carb is used on the Moki 250?
Old 12-24-2013, 02:38 PM
  #2731  
Greg Wright
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Walboro carb.
Old 12-24-2013, 02:44 PM
  #2732  
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Yes, but what model.. should be a WT-something.
Old 01-02-2014, 06:04 AM
  #2733  
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I hope there are more clever people here than I am. I've been tuning my Moki 250 intake and exhaust ports so the there are no sharp bends and that the flow does not experience any unnecessary turbulence. Now I'm in a situation that with the tuned head I need to turn High and low needle half a turn richer to get it running smoothly. And still it takes the same revs than if I put my old non-tuned heads. With the non tuned head again I can close the needles by half a turn. So definitely the engine is getting more fuel/air mixture but why there is no rpm increase? All I could think up was that the droplet size would be bigger now with opening the needles and thus burning slower. Or could it be that there is now just more torque at lower rpm's? I did notice that it is responding better with the tuned heads. But I was expecting higher rpm with the increased fuel consumption.
Old 01-02-2014, 06:36 AM
  #2734  
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You sir, are much more ambitious than I am. I tip my hat to you. I have always been under the impression that a 2-stoke engine benefits more in rpm from tuning than a 4-stroke, as the Moki is. This engine has excess capabilities for the type aircraft I use them in anyway. 18 inch pitch really hauls the mail even at 4800. Bad things happen when these rev too high.

Last edited by ram3500-RCU; 01-02-2014 at 06:40 AM.
Old 01-02-2014, 07:48 AM
  #2735  
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Originally Posted by ram3500-RCU
You sir, are much more ambitious than I am. I tip my hat to you. I have always been under the impression that a 2-stoke engine benefits more in rpm from tuning than a 4-stroke, as the Moki is. This engine has excess capabilities for the type aircraft I use them in anyway. 18 inch pitch really hauls the mail even at 4800. Bad things happen when these rev too high.
I have a 32" three blade solo prop at about 18-19" pitch. It takes some 4300rpm on the ground which is the same than my 32x20" Menz. Also I've seen the soloprop to unload to 6500rpm in a shallow dive and at level flight close to 6000rpm. I have not tried the solo prop with the non-tuned heads so I don't know if there would be any differences. But I do find it strange not seeing any differences with higher fuel consumption...
Old 01-02-2014, 09:18 AM
  #2736  
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which is why I tach the Solo prop for no more than 3600 to 3800 on the ground. I don't go by the gauge on the prop. 6000 is way too high and 6500 in the danger zone.
Old 01-02-2014, 11:40 AM
  #2737  
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From my 4 stroke motorcycle racing days...smoothing the radii in the intake and exhaust manifolds and heads makes for a smoother mixture flow but may or may not change performance. What will help however is TUNING. Unless one could experiment with different length headers there might not be any performance gain available. As we've found out however,
the Moki radials don't need MORE performance. Out of the box they'll pull rediculously pitched props. Mitch
Old 01-02-2014, 11:43 AM
  #2738  
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Originally Posted by ram3500-RCU
which is why I tach the Solo prop for no more than 3600 to 3800 on the ground. I don't go by the gauge on the prop. 6000 is way too high and 6500 in the danger zone.
That's another funny thing, I remember reading it here that there is a electronic limit at 6000rpm starting to cut of ignition. well either it is not true or mine is not working.
Old 01-02-2014, 11:51 AM
  #2739  
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Originally Posted by nine o nine
From my 4 stroke motorcycle racing days...smoothing the radii in the intake and exhaust manifolds and heads makes for a smoother mixture flow but may or may not change performance. What will help however is TUNING. Unless one could experiment with different length headers there might not be any performance gain available. As we've found out however,
the Moki radials don't need MORE performance. Out of the box they'll pull rediculously pitched props. Mitch

Yes, well I don't need more power either, just want to see if it can give more power. And if it is now consuming more fuel, one would expect it would give more power. I suppose it could unload even bigger pitched props now in the air. Moreover, I felt that the lower cylinder at 5 O'clock is not cutting out the way it used to, meaning it is not so sensitive to the needle settings as before. Perhaps it gets better mixture there as well.
Old 01-05-2014, 07:25 AM
  #2740  
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Today I did some experiments. With the original heads with 32x24 soloprop it took 3470rpm (well the intake lines leaving the crackcase was smoothened). With the new head, the soloprop pitch was accidently 25", it took 3600 rpm. So it looks like it is the torque that was increased. Also the throttle respond is much better now and the lower cylinders keeps on firing a even running at low rpm's for longer periods. All in all, the engine is breathing better now. Almost forgot, the low rpm was 550 that it was able to keep. But now I must decide if I can use such a high pitch, It will unload to over 5000rpm so my corsair will fly very fast... With a 2-blade MenzS 32x20" it flew 250kmh.
Old 01-05-2014, 08:04 AM
  #2741  
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that is over 155 mph. the air frame is only rated for 125. other planes may benefit from what you are doing, but the CARF Corsair can't handle it. The stock Moki is more than enough.
Old 01-05-2014, 08:35 AM
  #2742  
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I repeat one of my earlier posts to ask, “What is the preoccupation with pitch” why not use a larger diameter prop?
A ¼ scale warbird doing 125mph that’s 500mph, they’re not going that speed at Reno! They just look ridiculous. Remember, pitch is for speed, diameter is for weight.
I have a three blade 32x12 on my La7 and it’s easy to get that flying too fast.

m
Old 01-05-2014, 09:02 AM
  #2743  
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Originally Posted by mick15
I repeat one of my earlier posts to ask, “What is the preoccupation with pitch” why not use a larger diameter prop?
A ¼ scale warbird doing 125mph that’s 500mph, they’re not going that speed at Reno! They just look ridiculous. Remember, pitch is for speed, diameter is for weight.
I have a three blade 32x12 on my La7 and it’s easy to get that flying too fast.

m
any piston engine that is propped has a parameter of optimal rpm for healthy operation. to achieve this target rpm with a given diameter, pitch must be considered to properly load the engine. A larger disc is not always available or practical. In the case of the Moki, being high torque, it benefits from a Lott of pitch and lower rpm. Modelers give way too little consideration to pitch. In full scale, pitch is a big consideration in engine operation.
Old 01-05-2014, 09:31 AM
  #2744  
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That's the point, if you have a very powerful engine, loading it up with pitch makes the model fly faster, to the point where they are flying too fast and do not look scale so, you load the engine with either diameter or more blades.

Fine pitch is like a low gear the plane will climb better accelerate better and so on, that's why planes take off in fine pitch then go to course for cruising speed.

m
Old 01-05-2014, 09:46 AM
  #2745  
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Originally Posted by mick15
That's the point, if you have a very powerful engine, loading it up with pitch makes the model fly faster, to the point where they are flying too fast and do not look scale so, you load the engine with either diameter or more blades.

Fine pitch is like a low gear the plane will climb better accelerate better and so on, that's why planes take off in fine pitch then go to course for cruising speed.

m
with all do respect, I can't agree. speed is the result of pitch AND rpm. A 2-stroke turning the same diameter prop with far less pitch at far more rpm can be going the same relative speed as a 4-stroke with twice the pitch yet half the rpms, but both engines will be their power zone. have you ever heard of a constant speed prop? It is all about pitch.
Old 01-05-2014, 10:03 AM
  #2746  
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Yes that is a statement of the obvious, what it ignors though is there are two types of pilot, one who uses throttle management and the other who flys the whole flight flat out.


Yes it is about pitch but the engine/airframe has to have the correct diameter quotiant to start with.

m
Old 01-05-2014, 10:39 AM
  #2747  
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You asked why the preoccupation with pitch. that was my focus. there are indeed other considerations including ground clearance, engine compartment size, scale appearance, style of flying, and more, but always, no matter what the engine choice, the engines health dictates consideration of pitch given the selected disc.
Old 01-06-2014, 05:21 AM
  #2748  
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Originally Posted by ram3500-RCU
that is over 155 mph. the air frame is only rated for 125. other planes may benefit from what you are doing, but the CARF Corsair can't handle it. The stock Moki is more than enough.
I know the CARF corsair cannot handle the speeds my plane is running at. Therefore it is good that it is not a CARF model, but a build from Don Smith plans. And for the scale appearance, it is already overpowered. I've measured over 60# of thrust with the soloprop. And the plane weights the same. So if I want to fly scale and will have to use the throttle. And now with the new heads, even more. I have been thinking of going bigger diameter, but have not seen good ones yet. 38" would be scale size, but that might be too big for the moki.
Old 01-06-2014, 05:30 AM
  #2749  
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very cool. what is the wing spam? it would be c Cool to have a corsair done in one of the Reno schemes and capable of speeds you are talking about.
Old 01-06-2014, 05:42 AM
  #2750  
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Originally Posted by ram3500-RCU
very cool. what is the wing spam? it would be c Cool to have a corsair done in one of the Reno schemes and capable of speeds you are talking about.
It is the 120" version, but modified with hydraulic wing folding. I've also had the thought of repainting it to the Reno schemes, but we'll see.

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