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MOKI RADIAL Care and Maintenence

Old 07-23-2013, 09:16 PM
  #2576  
goodinmw
 
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Default RE: MOKI RADIAL Care and Maintenence

Aloha!
I've been running a solo 3 blade 26in dia propeller for several years on a ~50lb wet Corsair. I believe the pitch is somewhere between 17 and 18.
I tweaked the pitch until I was pulling ~4600RPM on the ground at full throttle. Big plane flies great.
It took me a while to get the 150 running on all cylinders- 50:1 racing oil ratio, swirl vanes in the intake tube behind the carb and leaned the mixture a bit.
Starts like a charm, sounds great and pulls with authority.
(I specifically went after the adjustable prop because with previous planes I'd invested at least as much buying multiple propellers to find the right combination of pitch and diameter for the engine/airframe)
I have a backup composite propeller- 3 blade 26x14 (Biela I think) which turns up to about 5000 RPM, and the plane is really fast- but the solo prop looks and sounds better running a bit slower RPM.
Good luck!
Mark
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Old 07-24-2013, 03:34 AM
  #2577  
wphilb
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Default RE: MOKI RADIAL Care and Maintenence

I have two 28 x 12 props and did not care for them, but I'll happily loan you one if you want to try, I think they are too light in pitch for the motor but they were what was recommended when I bought the plane.

Send me a PM if you want, just return when done.

Whit 
Old 07-24-2013, 04:43 AM
  #2578  
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Default RE: MOKI RADIAL Care and Maintenence

I appreciate the offer... I also think the 28x12 is too light of a pitch, but I haven't tried one. If folks are pulling 50 pound planes around with this motor and satisfied with the performance, then I may not be getting everything out of this motor that I think I am.

This is a post-2009 motor, so the turbulator wouldn't help. I did upgrade to the Rainbow-tronics ignition and that helped tremendously.

I guess it's possible that the motor has been heating up and giving poor performance. I opened up the cowl quite a bit and added vents, I'll give that a try on the props that I have and see what I need to do next.

Here's some before and after pictures of the cowl work. The cowl opening increased from about 6 1/2 to 8 1/2 inches.

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Old 07-24-2013, 06:20 AM
  #2579  
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Default RE: MOKI RADIAL Care and Maintenence

From a quick look of the pictures, I don't see a lot of cowl exit area. Someplace I though I read you need as much or more exit area as inlet. My Corsair has full cowl flaps I run wide open. Will try to post some pictures this evening when I get home.
Mark
Old 07-24-2013, 06:26 AM
  #2580  
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Default RE: MOKI RADIAL Care and Maintenence

Yep.. the area under those 2 metal louvers is open, and the entire area under the "oil cooler" (the thing sticking down from the bottom of the cowl) is open... about 4 inches wide and 7 inches long.

One of the guys at our field has a corsair opens/closes the cowl flaps with the throttle.. very nice.
Old 07-24-2013, 08:43 AM
  #2581  
Greg Wright
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Default RE: MOKI RADIAL Care and Maintenence

You should really put some Baffles between each cylinder then you would see a noticeable difference in temps of the engine.
Old 07-24-2013, 10:25 AM
  #2582  
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Default RE: MOKI RADIAL Care and Maintenence

I'm amazed its not overheating. 

I have baffles between each cylinder and wide open cowl flaps, I have at least 1:3 inlet : outlet ratio and still mine is still cutting out in flight. Do you have the ignition in any cooling airflow?

Whit
Old 07-24-2013, 10:31 AM
  #2583  
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Default RE: MOKI RADIAL Care and Maintenence

Ignition must NOT get hot. Then it will start "quiting", and finally stop....
Old 07-24-2013, 02:41 PM
  #2584  
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Default RE: MOKI RADIAL Care and Maintenence

My engine at Joe Nall lost power but kept running. This last time as far as I could tell it went from "fine" to "off" almost instantly. There was not stuttering or gradual power loss, just "off." I assumed overheating due to previous results.

What should I see if. It's an ignition overheating?

Whit
Old 07-24-2013, 03:07 PM
  #2585  
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Default RE: MOKI RADIAL Care and Maintenence

Baffles are next on my to do list.... is everyone just securing with wire to the cylinders?
Old 07-24-2013, 04:19 PM
  #2586  
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Default RE: MOKI RADIAL Care and Maintenence

I have done baffling two ways, one is attached to the frame that the cowl bolts to, another is a ring made up of 5 sections of roofing aluminum pop riveted together to make a complete ring, then bolted to the exhaust pipes with a two part clamp. Was complicated but allowed the cowl to be removed by rotating (not possible with baffles as part of cowl) and stay as part of the engine so I can switch between planes, baffles come along as part of the engine "package." 

Easiest is either wired around cylinders as you mention or glue and fiberglass to the cowl, assumes your cowl just slides on for and aft.

I think a few pages back I posted some pics.

I have a template I could scan and email you, or drop in post. Though creating one is really easy, just a cardboard triangle, cut away crudely until it fits in between the cylinder, then build up with bits of tape until you have what you want, transfer that to a second bit of cardboard and check fit, adjust if needed.

Whit
Old 07-24-2013, 04:49 PM
  #2587  
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Default RE: MOKI RADIAL Care and Maintenence

Old 07-24-2013, 05:14 PM
  #2588  
GaryM
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Default RE: MOKI RADIAL Care and Maintenence


ORIGINAL: wphilb

My engine at Joe Nall lost power but kept running. This last time as far as I could tell it went from ''fine'' to ''off'' almost instantly. There was not stuttering or gradual power loss, just ''off.'' I assumed overheating due to previous results.

What should I see if. It's an ignition overheating?

Whit

Whit, my 150 ran awesome until the daily temps got into the low nineties. About three minutes into the flight the motor had a distinct interruption or miss that occurred about every 1 1l2 to 2 seconds. No sagging but a slight loss of power and the miss. About the third time this happen, I took the wing off immediately upon landing and was packing up to leave. Just out of curiosity I was pushing on the connector on the back of the ignition and found I could not keep my hand on the module as it was that hot.

My firewall has at least three holes in it that are an inch in dia plus one big one right behind the carb.

In order to get cool air flowing over the ignition I was able to open up one of the air intakes on the leading edge of the wing (corsair) and duct air from it to the ignition. Instantly solved the problem and has not reoccurred

Not sure if your problem is this but you might put it on your list of things to check

Good Luck
Old 07-24-2013, 06:35 PM
  #2589  
mogman
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Default RE: MOKI RADIAL Care and Maintenence

This is how I baffled my 400 in the Waco using thin aluminum. I was (still am) concerned that not much air is hitting the ex. collector ring, but so far it seems to have been running ok. Not sure what the temps are.

Cheers,
Dave.
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Old 07-25-2013, 03:59 AM
  #2590  
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Default RE: MOKI RADIAL Care and Maintenence

Gary,

Are you saying that the firewall holes help or hurt the ignition module cooling? My module is right behind the firewall with only the open carb hole and one other smaller one for the plug wires.

Not sure I can duct air from my LE inlets without lots of surgery but opening a duct from a new hole on the firewall might be doable, open a matching hole in the baffles and duct clean cool air to it?

Which module was that hot? I have the new Rainbow Troincs with two modules, wondering which needs the airflow most.

Thanks!!

Whit


ORIGINAL: GaryM


ORIGINAL: wphilb

My engine at Joe Nall lost power but kept running. This last time as far as I could tell it went from ''fine'' to ''off'' almost instantly. There was not stuttering or gradual power loss, just ''off.'' I assumed overheating due to previous results.
What should I see if. It's an ignition overheating?
Whit

Whit, my 150 ran awesome until the daily temps got into the low nineties. About three minutes into the flight the motor had a distinct interruption or miss that occurred about every 1 1l2 to 2 seconds. No sagging but a slight loss of power and the miss. About the third time this happen, I took the wing off immediately upon landing and was packing up to leave. Just out of curiosity I was pushing on the connector on the back of the ignition and found I could not keep my hand on the module as it was that hot.

My firewall has at least three holes in it that are an inch in dia plus one big one right behind the carb.

In order to get cool air flowing over the ignition I was able to open up one of the air intakes on the leading edge of the wing (corsair) and duct air from it to the ignition. Instantly solved the problem and has not reoccurred

Not sure if your problem is this but you might put it on your list of things to check

Good Luck
Old 07-25-2013, 05:59 AM
  #2591  
Brian Rawcliffe
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Default RE: MOKI RADIAL Care and Maintenence

reyn3545. I hope the following will be of some help to you,based on my experience.
I purchased my Moki 150 ser.no.150075 in 2007, and to ths day it remains totally standard, no modifications whatsoever,and in 80+ show flights and countless fly-in's etc. it has never let me down.
The only lubrication I have ever used is BEL-RAY HIR SYNTHETIC,at a mixture of 40-1, and I can honestly say that I have never had an oily plug or loss of a cylinder.The ignition battery is a Sanyo Eneloop 4.8 volts 2000 ma, and after six show flights a capacity cycle usually indicates 800/900 m/a
remaining.Also my ignition unit is mounted inside the firewall, so it is not subject to engine temperature.
The only prop size I have used is a 28"x 12" which turns at 5100 rpm on the ground,and the performance is more than adequate, pulling my 42lbs
warbird round in style. In fact if you pull the back you can do a loop over the moon if desired.
The model is the Roy Vaillancourt Hawker Tempest modified to the mk11 variant, dry weight 42lbs.

My cooling method. I have been asked many times over the last few flying seasons how I have successfully and reliably operated my Moki 150.
firstly, it is absolutely essential to get sufficient cooling to the cylinders, and with a cowl diameter of 11" which has a radius front end, that leaves just an aperture of 7" with a spinner diameter of 6.3/8" the remaining air gap is only 5/8" all round.To maximise the airflow I have individually baffled each cylinder, and the method of fabrication can be clearly seen in the photo's.

The front plate is 1/16" ply with the side, top and bottom close fitting baffles made from 3/32" hard balsa. The whole unit is held in place by 4 screws onto hardwood blocks epoxied to the inside of the cowl. Additional air flow has been achieved by drilling the spinner backplate with a circle of 1?" holes (see photo). These line up with the bottom of the cylinders, and with the forward motion of the model air will pass through the spinner/propcut-outs and the holes in the backplate onto the cylinders. Whether of not the cooling would be adequate without this additional air flow would only be determined by blanking of the holes and flying the model. And I cannot see the point of doing this.

With the above set-up I have flown the Tempest on 90F temperatures without any reduction in R.P.M. Over the last 3 years, other than check out flights I have only flown the model at public shows or fly-ins, and after each show etc. I remove the spinner, prop, and cowl to do routine maintenance as follows:-
Check valve clearance with engine cold, should be 0.05mm - 0.08mm, lightly oil rocker arms, push rod ends and valve stems with WD40, check and tighten if required the collector ring gland nuts, these have a tendency to work loose after 10 to 12 flights, check the collector tube from the airpump to the carburettor, this can become at least partially blocked by grease and if necessary remove and clean. Make sure that all the plug caps are firmly in place and finally check all cylinder head and body bolts are fully tight.

All the above checks take no more than 1 hour to complete, and you are confident that the engine is ready for your next flying session.

Baffle plate photo 1
Baffle fabrication photo 2
Baffle mounted inside cowl photo 3
Spinner backplate photo 4
Cowl fixing blocks photo 5
Front view of model (see baffle behind spinner) photo 6
Flying shot (Courtesy Neil Hutchinson)
Old 07-25-2013, 06:05 AM
  #2592  
Brian Rawcliffe
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Default RE: MOKI RADIAL Care and Maintenence

Sorry about the photo's will try again
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Old 07-25-2013, 07:51 AM
  #2593  
GaryM
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Default RE: MOKI RADIAL Care and Maintenence


ORIGINAL: wphilb

Gary,

Are you saying that the firewall holes help or hurt the ignition module cooling? My module is right behind the firewall with only the open carb hole and one other smaller one for the plug wires.

Not sure I can duct air from my LE inlets without lots of surgery but opening a duct from a new hole on the firewall might be doable, open a matching hole in the baffles and duct clean cool air to it?

Which module was that hot? I have the new Rainbow Troincs with two modules, wondering which needs the airflow most.

Thanks!!

Whit


ORIGINAL: GaryM


ORIGINAL: wphilb

My engine at Joe Nall lost power but kept running. This last time as far as I could tell it went from ''fine'' to ''off'' almost instantly. There was not stuttering or gradual power loss, just ''off.'' I assumed overheating due to previous results.
What should I see if. It's an ignition overheating?
Whit

Whit, my 150 ran awesome until the daily temps got into the low nineties. About three minutes into the flight the motor had a distinct interruption or miss that occurred about every 1 1l2 to 2 seconds. No sagging but a slight loss of power and the miss. About the third time this happen, I took the wing off immediately upon landing and was packing up to leave. Just out of curiosity I was pushing on the connector on the back of the ignition and found I could not keep my hand on the module as it was that hot.

My firewall has at least three holes in it that are an inch in dia plus one big one right behind the carb.

In order to get cool air flowing over the ignition I was able to open up one of the air intakes on the leading edge of the wing (corsair) and duct air from it to the ignition. Instantly solved the problem and has not reoccurred

Not sure if your problem is this but you might put it on your list of things to check

Good Luck
Whit, my ignition is the stock one.
Heat was coming in thru the holes in the firewall.
So I closed them off the best I could and then ducted cool air over the module to help even more.

Gary
Old 07-25-2013, 11:10 AM
  #2594  
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Default RE: MOKI RADIAL Care and Maintenence

Gary,

Thanks!

Whit
Old 08-09-2013, 06:50 AM
  #2595  
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Here something new. I have a moki 250cc with Carf version of the soloprop, which has 32" CF blades, 3-blade. The other day I was flying with the prop for the first time. The pitch was measured about 18-19". On the ground it took 4290rpm, which is fairly good. Started flying and asked a friend of mine to check the online rpm's. In level flight 5500rpm. And, In a shallow dive 6500rpm, Shouldn't there be a ignition cuttoff @ 6000rpm?I instantly throttled down for not loosing any valve pushrods.

So it looks like that the engine has the capability of unloading to maximum revs or beyond almost any prop. My two blade 32X20 unloaded to from 4350 rpm to 5700rpm. So I see only way to go is bigger props like 34X16 3-blade. has anyone tried these? Moreover, I must wonder the recommended props that the sellers are giving for these engines. I have the recommended 30X16 3-blade from Fiala which takes 4950 rpm on the ground. This feels small from the start. EDIT: both props gives the same static thurst, about 60#

And can you imagine the sound of 32" blade @6500rpm. Not for warbids like my corsair. It is starting to look like that the torque of these engines is far greater than expected...

Last edited by jairaksinen; 08-09-2013 at 06:54 AM.
Old 08-09-2013, 06:54 AM
  #2596  
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Glad to see the forums back alive... I have a question about the smoke fitting on the exhaust ring....

Does anyone know where I can find a smoke injector that will screw into that fitting? This is a Moki 150 if that makes any difference.
Old 08-09-2013, 08:53 AM
  #2597  
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I would check with Gotz at Vogelsang Aeroscale, he should know. He might have something in stock.

Whit
Old 08-09-2013, 09:02 AM
  #2598  
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been there, done that. Goetz didn't have any in stock and didn't have any recommendations. I saw from some earlier posts in this thread that TroyBuilt may have something that may work... I'll give that a try later today.
Old 08-09-2013, 10:22 AM
  #2599  
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Hmm, it's just a hollow, threaded barbed fitting right? Need to know thread size and pitch, then look on McMaster Carr.com, they have everything.

let us know if you find the right part, I'm sure others will want to know.

Whit
Old 08-09-2013, 10:27 AM
  #2600  
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Atleast in my 250cc it is M5 threads. I would imagine it to be the same in the 150cc.

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