MOKI RADIAL Care and Maintenence
06-10-2013, 03:20 AM
#2502
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: Maxam
30x16
30x16
Tom,
a good recommendation.
On a 250, best 2-blade is around 32x18. Maybe a little bigger with finer pitch on a slow biplane.
06-10-2013, 04:06 AM
#2503
My Feedback: (62)
RE: MOKI RADIAL Care and Maintenence
Detlef, I used a 32x18 on my 215 and I had to throttle back on a dive. On the same plane I switched to a 33 X16 and have better performance. It is a 37% Yak 55 SP weighing 32 pounds. Those SEP laminated props have good balance and performance. -Tom
06-11-2013, 06:55 AM
#2505
RE: MOKI RADIAL Care and Maintenence
I will start flying with a Biela 32x18 on my 250. In Biela website said that is the right Prop for 250.
But I didn't check the RPM yet...
But I didn't check the RPM yet...
06-11-2013, 10:56 AM
#2506
My Feedback: (51)
Join Date: Oct 2002
Location: Repentigny,
QC, CANADA
Posts: 128
Likes: 0
Received 0 Likes
on
0 Posts
RE: MOKI RADIAL Care and Maintenence
I would like to install a smoke system on my 215. What is the best way to tap and get equal amounts of smoke on both of my pipes.
1 nipple at the top
2 Two nipples just below the two top cylinders.
Thanks
1 nipple at the top
2 Two nipples just below the two top cylinders.
Thanks
06-11-2013, 12:11 PM
#2507
Junior Member
Join Date: Aug 2005
Location: Falkoping, SWEDEN
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
RE: MOKI RADIAL Care and Maintenence
Regarding prop sizes:
I have a Krill Models, Yak 55 37% with a Moki 250. I use the Turbulator and a fuel pump. 2% oil.
I have run 2 seasons with a 32x18 but discovered that it revs to high in flight (over 5.000 rpm). I switched to 32x22 and I like it. It now revs 4.600 at full throttle flying straight.
I think many are afraid of using high pitch, but I see these benefits: Not overrevving this precious engine, less noise, better IMAC performance! and better efficiency. I see many use to low pitch in my opinion.
just my 2 cents...
/Clarence
I have a Krill Models, Yak 55 37% with a Moki 250. I use the Turbulator and a fuel pump. 2% oil.
I have run 2 seasons with a 32x18 but discovered that it revs to high in flight (over 5.000 rpm). I switched to 32x22 and I like it. It now revs 4.600 at full throttle flying straight.
I think many are afraid of using high pitch, but I see these benefits: Not overrevving this precious engine, less noise, better IMAC performance! and better efficiency. I see many use to low pitch in my opinion.
just my 2 cents...
/Clarence
06-11-2013, 12:26 PM
#2509
Junior Member
Join Date: Aug 2005
Location: Falkoping, SWEDEN
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: reyn3545
You are using the radial engine for IMAC competition?
You are using the radial engine for IMAC competition?
/Clarence
06-11-2013, 12:50 PM
#2510
My Feedback: (62)
RE: MOKI RADIAL Care and Maintenence
I am using a 33x16 on my Yak 55SP weighing 32 pounds. What I have found is on the ground the prop loads the engine at 4400 rpm. When going at a high rate of speed or in a dive I of course throttle down. But going straight up the performance is extraordinary nearly out of sight. If I put a huge pitch prop on the engine, it is overloaded and cannot produce high HP in a climb and the performance suffers greatly. Discipline required!!! -Tom
06-12-2013, 03:48 AM
#2512
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: Maxam
I am using a 33x16 on my Yak 55SP weighing 32 pounds. What I have found is on the ground the prop loads the engine at 4400 rpm. When going at a high rate of speed or in a dive I of course throttle down. But going straight up the performance is extraordinary nearly out of sight. If I put a huge pitch prop on the engine, it is overloaded and cannot produce high HP in a climb and the performance suffers greatly. Discipline required!!! -Tom
I am using a 33x16 on my Yak 55SP weighing 32 pounds. What I have found is on the ground the prop loads the engine at 4400 rpm. When going at a high rate of speed or in a dive I of course throttle down. But going straight up the performance is extraordinary nearly out of sight. If I put a huge pitch prop on the engine, it is overloaded and cannot produce high HP in a climb and the performance suffers greatly. Discipline required!!! -Tom
06-12-2013, 04:33 AM
#2513
My Feedback: (62)
RE: MOKI RADIAL Care and Maintenence
Reyn, It is the Ohio Model Products 108" 55 SP. No weight was added. The rear structure of the fuselage allowed me to install a hatch and battery box at the very rear under the stab. The throttle and choke servos are next to the rudder servo. I was obsessive moving everything to the rear so no weight would be added. Frankly the plane seemed to be made for this engine. The canister tunnel is perfect to assist with cooling as well as the 44 louvers in the cowl.
-Tom
-Tom
06-16-2013, 11:13 PM
#2515
Senior Member
Join Date: Jul 2003
Location: Brisbane, AUSTRALIA
Posts: 486
Likes: 0
Received 0 Likes
on
0 Posts
RE: MOKI RADIAL Care and Maintenence
Guys, I have a question for Moki 150 owners. I'm thinking of building 30's racer in the future, so I wonder, what would be the best prop for speed? Also, I finally invested in APC pump but didn't notice any difference in power.
Do you actually have to lean out your needles? And if so, how much?
Many thanks
Do you actually have to lean out your needles? And if so, how much?
Many thanks
06-17-2013, 08:09 AM
#2516
My Feedback: (10)
RE: MOKI RADIAL Care and Maintenence
What I have been told is that 180 to 200 degrees F is acceptable, 200 to 220 F is of concern, in excess of 220 F is unacceptable and must be addressed.
Whit
PS, I'm no expert, would love to hear from more experienced users on this.
Whit
PS, I'm no expert, would love to hear from more experienced users on this.
ORIGINAL: heraldoboldrin
what is the temperature that the moki 250 can get?
what is the temperature that the moki 250 can get?
06-20-2013, 10:56 PM
#2517
RE: MOKI RADIAL Care and Maintenence
Just finished a second hand AW 42% Yak and I did use a Mustang propeller.
[youtube]http://www.youtube.com/watch?v=p90lU8D0tho[/youtube]
I do want to use a threbladed on this one, any suggestion?
[youtube]http://www.youtube.com/watch?v=p90lU8D0tho[/youtube]
I do want to use a threbladed on this one, any suggestion?
06-21-2013, 04:17 AM
#2518
RE: MOKI RADIAL Care and Maintenence
I purchased a new 250, which I fitted to my Sea Fury and ran yesterday. I spent a time adjusting the mixture but could not get it to sound just right it seemed to have a misfire and sounded uneven.
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m
06-21-2013, 05:06 AM
#2519
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: mick15
I purchased a new 250, which I fitted to my Sea Fury and ran yesterday. I spent a time adjusting the mixture but could not get it to sound just right it seemed to have a misfire and sounded uneven.
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m
I purchased a new 250, which I fitted to my Sea Fury and ran yesterday. I spent a time adjusting the mixture but could not get it to sound just right it seemed to have a misfire and sounded uneven.
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m
Mick, what you guess is right; thats why it should be checked with a 5cylinder radial every other two full turns, not only one side
06-21-2013, 05:20 AM
#2520
RE: MOKI RADIAL Care and Maintenence
Well if that's the case someone should educate the factory because that is how it was out of the box.
It's also strange as none of my other engines exhibit this problem?
m
It's also strange as none of my other engines exhibit this problem?
m
06-21-2013, 05:55 AM
#2521
RE: MOKI RADIAL Care and Maintenence
The Evolution radials (UMS/Seidel) are made the same way and Horizon states in the instructions that the valve lash is to be checked in several different rotational positions.
However, in checking two different engines, I found NO appreciable difference in valve clearance regardless of rotational position. This would seem to indicate a high level of machining precision.
However, in checking two different engines, I found NO appreciable difference in valve clearance regardless of rotational position. This would seem to indicate a high level of machining precision.
06-21-2013, 06:37 AM
#2523
My Feedback: (14)
Join Date: Aug 2002
Location: Copeville,
TX
Posts: 453
Likes: 0
Received 0 Likes
on
0 Posts
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: mick15
I purchased a new 250, which I fitted to my Sea Fury and ran yesterday. I spent a time adjusting the mixture but could not get it to sound just right it seemed to have a misfire and sounded uneven.
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m
I purchased a new 250, which I fitted to my Sea Fury and ran yesterday. I spent a time adjusting the mixture but could not get it to sound just right it seemed to have a misfire and sounded uneven.
So, after allowing the motor to cool down I decided to check the valve clearances and here’s what I discovered.
I set the clearance on the number one cylinder and for some reason I rotated the engine two whole turns so #1 cylinder was again at TDC on the firing stroke and………………..the exhaust valve had NO clearance!
I repeated this action on the remaining four cylinders with the same result, on all exhaust valves the clearance set was either gone or double the value each time the motor was rotated through 720deg.
I have described this anomaly to the supplier of the engine who has agreed to contact the manufacturer; I will post the content of the reply.
The reason for this problem is, I believe inaccurate machining of the cam ring. Below is my explanation.
The Moki 5 works in a different way to automobile engine
Automobile engine has camshaft running at half engine speed so the same lobe always opens the same valve. The Moki has cam ring, which runs at quarter engine speed the cam ring has TWO inlet lobes and TWO
exhaust lobes, therefore the valves are opened by two different lobes
every 720º.
It would appear the cam ring in my engine has been poorly machined as when the exhaust valve clearance is set in one position it is incorrect on the following lobe.
In my view, if the engine is run under these conditions ie one cam clearance correct the other holding the valve open damage to the valve and seat is inevitable.
m