MOKI RADIAL Care and Maintenence
08-11-2019, 05:45 PM
#4277
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Hi im new to moki engines. I'm going to purchase the moki s180 brand new that come with the blue box ignition. Any suggestion what I should chg or buy extra apart of the aps fuel pump? Is the blue box ignition from moki good or should I go for rainbow tonics?
08-12-2019, 08:14 AM
#4278
I purchased a new Moki 180 with blue ignition. Operated it per instructions, using the exact recommended lubricants, mixture, fuel pump, power, cooling, etc. I should add this is my second Moki – my first was a used 250 with the older Top Hat ignition. I never had any trouble with that engine.
My new 180 quickly experienced two ignition failures, back to back. Both failures were the HV Coil to cylinder #4 simply no longer firing. Both failures were covered under warranty, but were accompanied by all the usual testing, swapping of components, removing, shipping, reinstalling the engine, only to have to go through it all again a second time.
The second time it happened, I was told “I must be the unluckiest Moki owner on Earth, as having the same failures back-to-back was so unusual.”
After the second failure, rather than only replacing the bad coil, Moki replaced the entire coil pack. Since that time, the engine has run great for probably 10 flights (knocking on wood, fingers crossed….)
The good? All costs were covered by Moki under warranty.
The bad? TONS of my time troubleshooting, removing, packing, shipping, (having my Moki engine box torn up in shipping), re-installing, and doing it all a second time. NOT what I expected when I purchased a brand new engine.
ALL the Moki’s still use the original design coil packs buried inside the rear portion of the case. IMHO, I don’t consider this a good design, BUT the vast majority of Moki’s run fine for years, as did my first 250, so what do I know..?
The Blue Ignition allows the use of 2S Lithium batteries and has an ignition ‘arming’ feature, but I haven’t noticed any difference in the way the engine performs over the old Top Hat.
IF my ignition fails again, I will switch to an external electronic ignition, similar to the RainbowTronics.
08-14-2019, 12:38 AM
#4279
We are 2 pilots in Norway that had the same problem with the 180. Both new engines, started but didn`t fire on all 5 cyl. Both back to Airworld, came back again and still the same issue. Airworld just denied there was further problems.
Disassembled the whole ignition and went to Adrian at www.ch-ignitions.com and then it just worked very well ever since!
Disassembled the whole ignition and went to Adrian at www.ch-ignitions.com and then it just worked very well ever since!
08-14-2019, 12:59 AM
#4280
Hello guys,
We have same problems with defect coils on MOKI radials in France, even on brand new engines.......
and the After Sales -no- Service is terrific .........
To solve definitely problem with the black grease coming into the tube between the front of the engines and the WALBRO
WT carburetor ( and kill the pressure/depressure fuel pump....) I have upgraded engine with RCEXL electric fuel pump
and a upgraded carburetor with back fuel line to the tank. Follow my Facebook webpage " Modelisme Micromoteurs Service"
Video avaiable also on YouTube : https://www.youtube.com/watch?v=O0T9YkRnk04
We have same problems with defect coils on MOKI radials in France, even on brand new engines.......
and the After Sales -no- Service is terrific .........
To solve definitely problem with the black grease coming into the tube between the front of the engines and the WALBRO
WT carburetor ( and kill the pressure/depressure fuel pump....) I have upgraded engine with RCEXL electric fuel pump
and a upgraded carburetor with back fuel line to the tank. Follow my Facebook webpage " Modelisme Micromoteurs Service"
Video avaiable also on YouTube : https://www.youtube.com/watch?v=O0T9YkRnk04
08-15-2019, 02:41 AM
#4281
Hello guys, i am trying to find any data for valach 250 cc 4stroke gas engine but it is difficult to find any. Generally does anybody know if that engine has the same power or less than moki 250 does? I am planning of using it to my 1/4 scale sist fw 190 plane, turning 3blade Vdm blade type 32 inches diameter scale look prop from sl or ramoser or varioprop manugacturer. Thank you in advance.
08-15-2019, 05:25 PM
#4282
Join Date: Jun 2018
Location: Malaysia
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Hi...im going to buy a moki for my cy model La-7 96“ wing span. Either s180 or s215. I know the s215 is replaced with s250 and no more in production for s215.
Any good if I buy the s215? I saw the one selling it as a new engine is without the moki logo bagde (logo) on the engine. Does the old version without the logo? Please advice if I should go for the s215 or s180
Last edited by vickyz; 08-15-2019 at 05:28 PM.
08-15-2019, 11:49 PM
#4283
My Feedback: (360)
Choice of engine
The 215 and the 180 are very different size wise, and in terms of power. If the aircraft is suitable for the 180 size wise, then the 215 would most likely be way too big in diameter.
Another consideration is that the 180 seems to need an aftermarket ignition, like CH for example, to run properly, sadly, even brand new out of the box.
This is not the case with the 215/250, with many still running fine with the older top hat style ignition.
I would not worry about the badge on the front, as Moki has provided them for other companies to resell over the years, like RCS for example early on.
Another consideration is that the 180 seems to need an aftermarket ignition, like CH for example, to run properly, sadly, even brand new out of the box.
This is not the case with the 215/250, with many still running fine with the older top hat style ignition.
I would not worry about the badge on the front, as Moki has provided them for other companies to resell over the years, like RCS for example early on.
Last edited by IFLYBVM2; 08-15-2019 at 11:51 PM. Reason: Spelling
08-16-2019, 12:09 AM
#4284
Join Date: Jun 2018
Location: Malaysia
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The 215 and the 180 are very different size wise, and in terms of power. If the aircraft is suitable for the 180 size wise, then the 215 would most likely be way too big in diameter.
Another consideration is that the 180 seems to need an aftermarket ignition, like CH for example, to run properly, sadly, even brand new out of the box.
This is not the case with the 215/250, with many still running fine with the older top hat style ignition.
I would not worry about the badge on the front, as Moki has provided them for other companies to resell over the years, like RCS for example early on.
Another consideration is that the 180 seems to need an aftermarket ignition, like CH for example, to run properly, sadly, even brand new out of the box.
This is not the case with the 215/250, with many still running fine with the older top hat style ignition.
I would not worry about the badge on the front, as Moki has provided them for other companies to resell over the years, like RCS for example early on.
Thanks for detail info. My la7 cowling can be fit with moki s215. I need another help. What's the 3blade scale size prop and pitch to purchase for mokis215 to use on warbird. I'm prefer using the ramoser varioprop with adjustable pitch. What size do you guys use
08-18-2019, 03:49 AM
#4285
My Feedback: (7)
I thought I’d post the setup I'm using for my Moki 300. This setup is working GREAT so I thought some of you might be interested.
This is a 300 I bought lightly used. I don't think it was ever flown - it looks brand new. First thing I did is add synthetic gear oil to the cam case. Less than an ounce. The black (molybdenum?) grease is pretty "loose" so gear oil may not be necessary but I wanted the lube to spring instantly into action (after long sitting periods) so I thinned it a bit. Then I disconnected the air pump and added a Powerfuel RX fuel pump. I then rigged up a mix on my DX18 that constantly varies the speed of the pump with throttle position. So cool.
Now to power up the ignition and pump: around here the 3D boys are running Tech Aero IBEC units to power their ignitions right off the radio batteries. Triple filtered and optically isolated, they have built up an outstanding record of reliability when added to a powersafe setup like the Spektrum powersafe receivers. SO - I've got one IBEC running the ignition and one running the fuel pump. This means I will have just TWO BIG 2s lipos running my entire aircract with power safe redundancy. I know I'll hear from the skeptics at this point :-)
The video shows me in the process of balancing the SL prop. It is nothing less than a big piece of jewelry. And you'll also see, the whimpy test stand I built is NOT up to full power running. I underestimated the brute power of this thing. It's a BEAST. But the handling characteristics are just superb. It works like this: radio on, pump on, choke on, prop until it pops, choke off and then 3 or 4 blades later it's running. Just a p*ssycat. Until you advance that throttle. . .
This is a 300 I bought lightly used. I don't think it was ever flown - it looks brand new. First thing I did is add synthetic gear oil to the cam case. Less than an ounce. The black (molybdenum?) grease is pretty "loose" so gear oil may not be necessary but I wanted the lube to spring instantly into action (after long sitting periods) so I thinned it a bit. Then I disconnected the air pump and added a Powerfuel RX fuel pump. I then rigged up a mix on my DX18 that constantly varies the speed of the pump with throttle position. So cool.
Now to power up the ignition and pump: around here the 3D boys are running Tech Aero IBEC units to power their ignitions right off the radio batteries. Triple filtered and optically isolated, they have built up an outstanding record of reliability when added to a powersafe setup like the Spektrum powersafe receivers. SO - I've got one IBEC running the ignition and one running the fuel pump. This means I will have just TWO BIG 2s lipos running my entire aircract with power safe redundancy. I know I'll hear from the skeptics at this point :-)
The video shows me in the process of balancing the SL prop. It is nothing less than a big piece of jewelry. And you'll also see, the whimpy test stand I built is NOT up to full power running. I underestimated the brute power of this thing. It's a BEAST. But the handling characteristics are just superb. It works like this: radio on, pump on, choke on, prop until it pops, choke off and then 3 or 4 blades later it's running. Just a p*ssycat. Until you advance that throttle. . .
Last edited by mitchilito; 08-18-2019 at 04:05 AM.
08-18-2019, 05:47 PM
#4286
Join Date: Jun 2018
Location: Malaysia
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Guys lot of disscussion on mokis but i cant finish read it all.
Quick question.should i buy the old version rcs moki215? Bad review or good review? Some said the older version with bronze camgears which has been replaced with steel.
should i buy the latest version moki engines s180/s250.
Quick question.should i buy the old version rcs moki215? Bad review or good review? Some said the older version with bronze camgears which has been replaced with steel.
should i buy the latest version moki engines s180/s250.
Last edited by vickyz; 08-19-2019 at 12:40 AM.
08-18-2019, 07:05 PM
#4287
Join Date: Jun 2018
Location: Malaysia
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I thought I’d post the setup I'm using for my Moki 300. This setup is working GREAT so I thought some of you might be interested.
This is a 300 I bought lightly used. I don't think it was ever flown - it looks brand new. First thing I did is add synthetic gear oil to the cam case. Less than an ounce. The black (molybdenum?) grease is pretty "loose" so gear oil may not be necessary but I wanted the lube to spring instantly into action (after long sitting periods) so I thinned it a bit. Then I disconnected the air pump and added a Powerfuel RX fuel pump. I then rigged up a mix on my DX18 that constantly varies the speed of the pump with throttle position. So cool.
Now to power up the ignition and pump: around here the 3D boys are running Tech Aero IBEC units to power their ignitions right off the radio batteries. Triple filtered and optically isolated, they have built up an outstanding record of reliability when added to a powersafe setup like the Spektrum powersafe receivers. SO - I've got one IBEC running the ignition and one running the fuel pump. This means I will have just TWO BIG 2s lipos running my entire aircract with power safe redundancy. I know I'll hear from the skeptics at this point :-)
The video shows me in the process of balancing the SL prop. It is nothing less than a big piece of jewelry. And you'll also see, the whimpy test stand I built is NOT up to full power running. I underestimated the brute power of this thing. It's a BEAST. But the handling characteristics are just superb. It works like this: radio on, pump on, choke on, prop until it pops, choke off and then 3 or 4 blades later it's running. Just a p*ssycat. Until you advance that throttle. . .
https://m.youtube.com/watch?v=5RUNsRpKnZE
This is a 300 I bought lightly used. I don't think it was ever flown - it looks brand new. First thing I did is add synthetic gear oil to the cam case. Less than an ounce. The black (molybdenum?) grease is pretty "loose" so gear oil may not be necessary but I wanted the lube to spring instantly into action (after long sitting periods) so I thinned it a bit. Then I disconnected the air pump and added a Powerfuel RX fuel pump. I then rigged up a mix on my DX18 that constantly varies the speed of the pump with throttle position. So cool.
Now to power up the ignition and pump: around here the 3D boys are running Tech Aero IBEC units to power their ignitions right off the radio batteries. Triple filtered and optically isolated, they have built up an outstanding record of reliability when added to a powersafe setup like the Spektrum powersafe receivers. SO - I've got one IBEC running the ignition and one running the fuel pump. This means I will have just TWO BIG 2s lipos running my entire aircract with power safe redundancy. I know I'll hear from the skeptics at this point :-)
The video shows me in the process of balancing the SL prop. It is nothing less than a big piece of jewelry. And you'll also see, the whimpy test stand I built is NOT up to full power running. I underestimated the brute power of this thing. It's a BEAST. But the handling characteristics are just superb. It works like this: radio on, pump on, choke on, prop until it pops, choke off and then 3 or 4 blades later it's running. Just a p*ssycat. Until you advance that throttle. . .
https://m.youtube.com/watch?v=5RUNsRpKnZE
Im using tech aero for my saito radial fg33r3.no issue. I like it.
Are you flying it on moki? Any issue using tech aero? Etc firing...
08-27-2019, 11:26 AM
#4289
Hey Guys,
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
08-27-2019, 11:50 AM
#4290
My Feedback: (360)
Hey Guys,
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
I have always avoided using devices like the Spark Switch in my setups, as my opinion is that it is just another link in the chain, and another possible choke point in the system.
My current setup is using a A123 from Electrodynamics to power the pump and ignition. They are wired in such a way as to where they both cut on and off with one switch.
KISS principle rules in my book, with nothing used that's not 100 percent necessary. Having said that, I am sure lots of other guys are using the Spark Switch with success, but my feeling is to eliminate any potential trouble spots as I can. Your actual mileage, as they say, may vary....
-Mike O
08-27-2019, 03:42 PM
#4291
Hey Guys,
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
Just wanted to share a story with ya. Earlier this month we were flying the P47 with the Moki 250 up at a show in Canada. It flew great all weekend until the final flight on Sunday. We were screaming it down the runway centerline at about 10 foot high when the motor suddenly began to "blub blub blub pop blub blub" and loose power. No way to land on that pass so we turned left and hoped it would keep running. Well it did just barely until the throttle was reduced after it was back on the ground. We went over turned off the plane and radio and began to push it back to the pitts. When I looked down I noticed the ignition indicator light was flashing slowly (about a 2s cycle). Removal of the wing revealed the PowerBox Spark switch I was using to control both the ignition and the APS fuel pump was cycling on and off and was so hot it had begun to melt the plastic housing. After disconnecting the ignition/pump battery and letting everything cool down everything seems to be working just fine including the switch. The APS pump and the old Moki 250 top hat ignition are each rated at less than 1A and the spark switch is rated at 2A constant 4.5A peak. So something happened but I'm not sure what. I have gone back and measured the current of the pump while running and the ignition (non running) and they are both WELL below 1A each. Spoke to a technical rep at PowerBox and the consensus is that the switch was overloaded. So either the pump, the ignition or both began to draw excessive current ~OR~ the switch just went into thermal runaway and failed. I sure would like to know which. The suggestion from Powerbox is to separate the pump and the ignition on separate switches basically giving twice the current overhead on both the pump and the ignition. My plan is to re-install the dual switches and re-test the system with the engine running.
I just wanted to share my story to see if anyone else has had a similar experience or opinions on how better to proceed to determine what really happened.
One thing that was REALLY odd to me was that the spark switch was intermittently turning power on to the ignition and pump with the radio turned off on the Rx & Tx side.
The rating of the spark switch is dependent on the power dissipation. That is a factor of the input voltage vs the output voltage. So while you may not of been exceeding the current rating you were exceeding the power rating. It got too hot and gave up.
I'm curious what output voltage Spark switch you are using. For my customers with the old top hat ignition I modify the Spark to have an output of 5.3V as we did find 5.9V was too much for the top hat ignition and sometimes it would quit with long periods of full RPM.
08-28-2019, 04:06 AM
#4292
Join Date: Jun 2018
Location: Malaysia
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What is the consequences if i use higher power engine ( moki250 ) on a cy model la7 instead of moki s180. Many people are flying it on you tube with s180.and one of the guy said bigger prop will hit the ground if i use the s250. Any chance if i still wantrd to use s250 with small prop 27" -28" 3blade
08-28-2019, 08:14 AM
#4293
I have definitely seen the same thing with one customer melting the plastic cover on the Spark switch. I recommend 2 separate Spark switches and use one battery for the pump and ignition.
The rating of the spark switch is dependent on the power dissipation. That is a factor of the input voltage vs the output voltage. So while you may not of been exceeding the current rating you were exceeding the power rating. It got too hot and gave up.
I'm curious what output voltage Spark switch you are using. For my customers with the old top hat ignition I modify the Spark to have an output of 5.3V as we did find 5.9V was too much for the top hat ignition and sometimes it would quit with long periods of full RPM.
The rating of the spark switch is dependent on the power dissipation. That is a factor of the input voltage vs the output voltage. So while you may not of been exceeding the current rating you were exceeding the power rating. It got too hot and gave up.
I'm curious what output voltage Spark switch you are using. For my customers with the old top hat ignition I modify the Spark to have an output of 5.3V as we did find 5.9V was too much for the top hat ignition and sometimes it would quit with long periods of full RPM.
To answer your second question I am using 5.9V output from the sparkswitch at the recommendation of Gotz Vogelsang. We do not fly the ship at full throttle very often I find 1/2 to 3/4 throttle is plenty. I understood ignition voltages below 5.9 would produce a weak spark to the plugs. Good to know we have some margin there.
Thanks as always for your feedback!
08-28-2019, 02:12 PM
#4294
Thanks for the feedback! I guess I don't quite understand the power factor issue. If I understood you correctly (certainly not a given) if the issue is not the amount of current I am drawing through the switch but rather the "Input voltage vs the output voltage" i.e. power factor I do not see how installing two switches with just one battery will solve the problem. Isn't the voltage ratio (input vs output) at each switch the same in this scenario?
To answer your second question I am using 5.9V output from the sparkswitch at the recommendation of Gotz Vogelsang. We do not fly the ship at full throttle very often I find 1/2 to 3/4 throttle is plenty. I understood ignition voltages below 5.9 would produce a weak spark to the plugs. Good to know we have some margin there.
Thanks as always for your feedback!
To answer your second question I am using 5.9V output from the sparkswitch at the recommendation of Gotz Vogelsang. We do not fly the ship at full throttle very often I find 1/2 to 3/4 throttle is plenty. I understood ignition voltages below 5.9 would produce a weak spark to the plugs. Good to know we have some margin there.
Thanks as always for your feedback!
The power (i.e.heat) the Spark has to dissipate equals the current draw times the voltage drop. So for example if you have a fresh 2 cell lithium ion battery at 8.4V and a 5.9V Spark switch, with 1 amp draw you will dissipate 1 x (8.4-5.9) = 2.5 watts. At 2 amps it is 5 watts but if you use two switches each Spark is only dissipating 2.5 watts each.
If you were running a LiFePO4 battery at 6.6V, then at the same 1 amp current the power is only 1 x (6.6-5.9) = 0.7 watt. Nearly 1/4 the power/heat for the same current draw. I hope this helps rather than confuse.
I respect Gotz's opinion as he has helped me quite a few times with Moki but I can confirm that 5.9V is too much for the old top hat ignition at full RPM. I have tested this with a couple of the old ignitions. They were designed for a 4 cell 4.8V NiCad battery and I found 5.3V gives plenty of spark and you can run full RPM all day without the ignition getting too hot.
08-29-2019, 07:35 AM
#4297
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08-29-2019, 07:55 AM
#4298
Amsoil Dominator. Break-in calls for 30:1 mix. After break-in, 50:1. I personally run it at 40:1.
Tri-Flow lubricant for the exposed valve train. DO NOT spray on. Spray some into a small container and use a Q-Tip to dab the lube into all the critical valve train areas. This prevents an unnecessary mess.
MOST IMPORTANTLY, proper cooling for cowled installs REQUIRES baffles between cylinders.
Go with Vogelsang and/or Moki prop recommendations.
Prolonged, full throttle operation on the ground is NEVER a good thing for any radial. Brief periods of full throttle on the ground is OK (no longer than 20 seconds)
I have never heard of having to lubricate the cam. It is lubricated internally by the fuel/OIL mixture.
08-29-2019, 08:31 AM
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Thanks richard.. use full info.im using this for my radial saito. Its recommend to moki as per instruction.any one using it?
About filling oil into cam,i read on this forum.
richard, my friends are using s180 with 3 blade prop 25.9 x14 on 96" wingspan la7. If i were to install a 250cc but maintain the prop size 3 blade vario prop at 27-28" but higher pitch,will that be fine with 250cc ? Because the recommended prop size is 30" but it will hit the ground
About filling oil into cam,i read on this forum.
richard, my friends are using s180 with 3 blade prop 25.9 x14 on 96" wingspan la7. If i were to install a 250cc but maintain the prop size 3 blade vario prop at 27-28" but higher pitch,will that be fine with 250cc ? Because the recommended prop size is 30" but it will hit the ground
08-29-2019, 08:58 AM
#4300
I don't think you can go wrong, using Moki's oil recommendation... I am using what Goetz Vogelsang recommended per our live discussions on the subject.
Having used Red Line in all my gassers for years, with excellent results, I was going to stick with Red Line, but Goetz said that in a 4 stroke application, Red Line is less than ideal as it burns more readily than Amsoil Dominator.
These four strokes need oil to make its way out to the top end; if it burns, that doesn't happen. Two strokes don't have the same lubrication requirements.
I now use Amsoil Dominator in everything as I don't want the hassle of multiple oils. 2 or 4 stroke, I run everything on Amsoil Dominator 40:1.
I am running a SEP 26x15 3 blade prop on my 180. It pulls like a freight train and is very quiet.
Considering the SMALLEST 3 blade prop recommended for a Moki 250 is a 29x18, I see no way to utilize a 250 while maintaining the diameter of a 180 prop.
IMHO, a 250 is serious overkill for a 96" warbird. The 250 will haul a 110" 50 pound warbird with authority and is too much engine for the LA-7 you are proposing.
Having used Red Line in all my gassers for years, with excellent results, I was going to stick with Red Line, but Goetz said that in a 4 stroke application, Red Line is less than ideal as it burns more readily than Amsoil Dominator.
These four strokes need oil to make its way out to the top end; if it burns, that doesn't happen. Two strokes don't have the same lubrication requirements.
I now use Amsoil Dominator in everything as I don't want the hassle of multiple oils. 2 or 4 stroke, I run everything on Amsoil Dominator 40:1.
I am running a SEP 26x15 3 blade prop on my 180. It pulls like a freight train and is very quiet.
Considering the SMALLEST 3 blade prop recommended for a Moki 250 is a 29x18, I see no way to utilize a 250 while maintaining the diameter of a 180 prop.
IMHO, a 250 is serious overkill for a 96" warbird. The 250 will haul a 110" 50 pound warbird with authority and is too much engine for the LA-7 you are proposing.