MOKI RADIAL Care and Maintenence
05-29-2013, 08:13 AM
#2426
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: Detlef Kunkel
Folks, I understand your comments, but the answer is really simple.
DONT slow down on the throttle like lightning(!!)
Its a radial engine, has some characteristics due to the volume of the crankcase that the mixture is running through, and the careful owner deals (and can live) with those characteristics.
In fact, a carefully adjusted Moki WILL ALWAYS come to an extremely low idle ( if not quitting) for a second or so, when cut down too fast.
Believe me, thats normal AND a sign that the adjustment is the best you can do, with a primitive carb like we use here.
Dont worry about that, it WILL NOT happen in flight. In 8 years of flying Moki engines, there was no single second where I was in doubt about the engine. Not that it was always perfect, I had my share of issues, too. But it always brought me home safely.
And- once you know about that - be a little more easy on the throttle.
You are not in LeMans on the fast lane
Folks, I understand your comments, but the answer is really simple.
DONT slow down on the throttle like lightning(!!)
Its a radial engine, has some characteristics due to the volume of the crankcase that the mixture is running through, and the careful owner deals (and can live) with those characteristics.
In fact, a carefully adjusted Moki WILL ALWAYS come to an extremely low idle ( if not quitting) for a second or so, when cut down too fast.
Believe me, thats normal AND a sign that the adjustment is the best you can do, with a primitive carb like we use here.
Dont worry about that, it WILL NOT happen in flight. In 8 years of flying Moki engines, there was no single second where I was in doubt about the engine. Not that it was always perfect, I had my share of issues, too. But it always brought me home safely.
And- once you know about that - be a little more easy on the throttle.
You are not in LeMans on the fast lane
Good advise.. .thanks!
05-29-2013, 09:21 AM
#2427
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RE: MOKI RADIAL Care and Maintenence
Somebody set me straight, I thought the RCS was a Moki, I don't see any difference except that little round tag on the crankcase.
Ron
Waco Brother #216
Ron
Waco Brother #216
05-29-2013, 10:07 AM
#2429
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RE: MOKI RADIAL Care and Maintenence
Unfortunately I am having issues with my Moki 150 (with R-Tronics ignition) dying in flight. We had two dead sticks on three flights at Joe Nall, the last we aborted early when full throttle yielded poor results. It brought the plane home but died soon after landing. Gotz of Vogelsang Aerosclae had adjusted the needles so we were sure with those settings. The engine was too warm on the ground after the last flight so we strongly suspect overheating.
Recipe for fix is to switch prop from 28x12 to 26x16 and fly without the cowl, see if that solves the problem.
Whit
05-29-2013, 10:39 AM
#2430
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: wphilb
Unfortunately I am having issues with my Moki 150 (with R-Tronics ignition) dying in flight. We had two dead sticks on three flights at Joe Nall, the last we aborted early when full throttle yielded poor results. It brought the plane home but died soon after landing. Gotz of Vogelsang Aerosclae had adjusted the needles so we were sure with those settings. The engine was too warm on the ground after the last flight so we strongly suspect overheating.
Unfortunately I am having issues with my Moki 150 (with R-Tronics ignition) dying in flight. We had two dead sticks on three flights at Joe Nall, the last we aborted early when full throttle yielded poor results. It brought the plane home but died soon after landing. Gotz of Vogelsang Aerosclae had adjusted the needles so we were sure with those settings. The engine was too warm on the ground after the last flight so we strongly suspect overheating.
Recipe for fix is to switch prop from 28x12 to 26x16 and fly without the cowl, see if that solves the problem.
Whit
Whit, 28x12 is far too small for the engine, it revvs itself to death in the air. No wonder it is suffering....I would do the same if tortured so
What rpm did you read out on the ground, what airplane type ( size)?
Your engine will have reached the speed limit duringthe entire flight time. The ignition cuts it down and prevents severe damage, but that is nevertheless overheating the engine if this lasts constantly all flight long (!!).
05-29-2013, 11:10 AM
#2431
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: mogman
Something to do with the MOKI trademark, as I recall. RCS,MOKI and AMR= same engine.
Something to do with the MOKI trademark, as I recall. RCS,MOKI and AMR= same engine.
05-29-2013, 12:04 PM
#2432
Join Date: Apr 2006
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RE: MOKI RADIAL Care and Maintenence
One thing that amazes me, is that pilots are still overreving their radials, even if the subject have been discussed over and over again...
I see Mokis on youtube that are screaming for lower rpm, I read about pilots who tells about over five thousand revs with proudness...
One phrase comes to mind: "They are asking for it".
/Straightleg
I see Mokis on youtube that are screaming for lower rpm, I read about pilots who tells about over five thousand revs with proudness...
One phrase comes to mind: "They are asking for it".
/Straightleg
05-29-2013, 12:16 PM
#2433
RE: MOKI RADIAL Care and Maintenence
I'm not looking for more revs, just trying to validate with others who have owned them as to what I should expect. I've ordered a 26x18 prop just to get a little more bite and slow the motor down a little, but I realize I'll be fighting that prop on landings.. The plane weights about 32 pounds, so even the 26x16 I have on it should fly it well... but in flight, it seemed VERY slow. I don't think I was getting anywhere near the 5100 that I was seeing earlier at my house.
Just 2 flights so far, still chasing all the little things that we all do this early in the game.
Just 2 flights so far, still chasing all the little things that we all do this early in the game.
05-29-2013, 04:32 PM
#2435
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RE: MOKI RADIAL Care and Maintenence
I fly a 50lb model on a Moki 150, using either 26x16 2-blade or 24x18 3-blade props, and the performance is well above scale (fast, non-scale climb rates). With such a light model (30lbs) you should be able to pull huge loops!
The suggestions above are spot on. Props that do not load the engine enough will directly contribute the eventual destruction of the engine. Relative to measures made on the ground, RPM will increase by at least 300-600 RPM in the air, once the model is in forward flight and the propellor "unloads."
The suggestions above are spot on. Props that do not load the engine enough will directly contribute the eventual destruction of the engine. Relative to measures made on the ground, RPM will increase by at least 300-600 RPM in the air, once the model is in forward flight and the propellor "unloads."
05-29-2013, 05:24 PM
#2436
My Feedback: (10)
RE: MOKI RADIAL Care and Maintenence
Guys, I used the 28 x 12 prop because that's what $&@ (name withheld, no sense in beating a dead horse) told me that was the prop to use! Not sure what more a guy can do but listen to the guys who sold him the engine! I went back and forthwith them about my engine problems for quite a while and asked about the prop more than once. Gotz picked up on it at Joe Nall but he was not the seller of the engine!
That's number one. Number two is that I got 5200 rpm on the ground with that prop, Moki recommends running 5K RPM on the 150. Gotz called them directly and that's what they recommend, not the 4K of the larger engines. Guys running the 26 x16 get about the same RPMs on the ground so even though I knew about the 26 x 16, not immediately obvious that switching to that prop was the solution as upper RPM (on ground) is the same.
lastly, I can pretty honestly say that my 150 has only seen max throttle on the ground in testing and tweaking and it ran fine with no ignition cut outs. In the 35 lb BUSA N 28 1/3 throttle had it airborne, anything above half and it was climbing too much, never got it trimmed with enough down trim or engine thrust to come anywhere near full throttle and not have a space shuttle. The Meister F4u was a heavier plane at 42 lbs but less drag so just about the same, 1/2 throttle or a bit more at most during takeoff and climb and then cruise at that for the brief flight time I had in it. I only advanced to full once on the third flight to show Gotz how little engine I had which is when he called abort and I landed. I would be very happy with a 4K top end with whatever prop works so long as its reliable! No quest for high RPMs here.
Whit
05-29-2013, 05:31 PM
#2437
RE: MOKI RADIAL Care and Maintenence
Please keep us posted with your findings... sounds like your issues may be something other than the prop.
I saw that you upgraded to the Rainbow Tronics ignition.. so did I. Does your ignition cut out at middle to high RPM? I know they are designed to cut out once they reach an RPM max, but mine cuts out very briefly starting around the mid-range.
I saw that you upgraded to the Rainbow Tronics ignition.. so did I. Does your ignition cut out at middle to high RPM? I know they are designed to cut out once they reach an RPM max, but mine cuts out very briefly starting around the mid-range.
05-29-2013, 06:18 PM
#2438
My Feedback: (10)
RE: MOKI RADIAL Care and Maintenence
I hope it is the prop, it's quite a jump from a 12 to a 16 pitch, it could be unloading at lower throttle settings enough to overheat? Anyway we will test fly with the new prop and no cowl and see how that flies...
I get a rare miss, prob from number three but its rare. Audible but rare and very brief.
Whit
05-29-2013, 07:06 PM
#2439
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RE: MOKI RADIAL Care and Maintenence
I have never run a moki before but I'm thinking about getting a 180cc. I have a question about props as well. What would be the smallest diameter prop I could safely and reliably put on this motor and still have it perform well. My concern is having enough prop clearance for the plane I am thinking about putting it on. I believe a 26" prop would fit with a couple of inches to spare. Would you guys say probably not to go any smaller than that? I did read somwhere that somone is running a 24x14 prop on an moki150cc but I don't know anything more about it. I'm thinking that this motor will have plenty of power for my plane so I am not really concerned about getting the most rpms or the fastest speed out of it.
David
David
05-29-2013, 10:04 PM
#2442
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: Detlef Kunkel
David, I am running a 26x17 SEP 3-blades on the 180, and it revvs with the new ignition even higher than I would like to, measured at 4700 on the ground. For my taste, this is beginning to be too much. I will switch to a 26-18 ( 3-blade). The plane is a 20 kg (44 pounds)Ziroli Hellcat, and has reallyplenty of power, high speed and impressing climbing rate. A fun to fly.
A fourblade 25x18 could do well in your case.
Whit; as I told in my PM to you, you cannot be sure that it is NOT the ignition. But it makes a lot of sense to check a better suiting prop first.
Whan I hear things like rpm- increase by 300 or maybe 600 rpm in flight, I like to recall another example for prop setup and rpm-increase: My 2,8 m P47 on the Moki 250 weighs close to 68 pounds. I run a fourblade Solo 30" dia, pitch is not comparable with others due to lacking twist in the solo blades. So we need to look at the rpm. In my case,I went down to 3600 on the ground. The pitch is at maybe 15" average ( to small for this bird, I know)
The rpm in flight reaches 6000 !! more than once per flight, in a shallow dive. I am gentle on the stick then, not to damage the engine or prop. 6000 is the limit that SOLO calls for 30 dia blades !!
I stay with this setup, because the takeoff-power with this heavy airplane is second to none, ANDI am gentle with full throttle in flight, NEVER dive it steeply with max power. What I want to say: the setup is a compromise; good takeoff, but wrong once you gathered some speed. As long as the pilot knows what he has in his hands, I think its OK.
But I would not let another jockey fly that one
ORIGINAL: davidgeorge212
I have never run a moki before but I'm thinking about getting a 180cc. I have a question about props as well. What would be the smallest diameter prop I could safely and reliably put on this motor and still have it perform well. My concern is having enough prop clearance for the plane I am thinking about putting it on. I believe a 26" prop would fit with a couple of inches to spare. Would you guys say probably not to go any smaller than that? I did read somwhere that somone is running a 24x14 prop on an moki150cc but I don't know anything more about it. I'm thinking that this motor will have plenty of power for my plane so I am not really concerned about getting the most rpms or the fastest speed out of it.
David
I have never run a moki before but I'm thinking about getting a 180cc. I have a question about props as well. What would be the smallest diameter prop I could safely and reliably put on this motor and still have it perform well. My concern is having enough prop clearance for the plane I am thinking about putting it on. I believe a 26" prop would fit with a couple of inches to spare. Would you guys say probably not to go any smaller than that? I did read somwhere that somone is running a 24x14 prop on an moki150cc but I don't know anything more about it. I'm thinking that this motor will have plenty of power for my plane so I am not really concerned about getting the most rpms or the fastest speed out of it.
David
David, I am running a 26x17 SEP 3-blades on the 180, and it revvs with the new ignition even higher than I would like to, measured at 4700 on the ground. For my taste, this is beginning to be too much. I will switch to a 26-18 ( 3-blade). The plane is a 20 kg (44 pounds)Ziroli Hellcat, and has reallyplenty of power, high speed and impressing climbing rate. A fun to fly.
A fourblade 25x18 could do well in your case.
Whit; as I told in my PM to you, you cannot be sure that it is NOT the ignition. But it makes a lot of sense to check a better suiting prop first.
Whan I hear things like rpm- increase by 300 or maybe 600 rpm in flight, I like to recall another example for prop setup and rpm-increase: My 2,8 m P47 on the Moki 250 weighs close to 68 pounds. I run a fourblade Solo 30" dia, pitch is not comparable with others due to lacking twist in the solo blades. So we need to look at the rpm. In my case,I went down to 3600 on the ground. The pitch is at maybe 15" average ( to small for this bird, I know)
The rpm in flight reaches 6000 !! more than once per flight, in a shallow dive. I am gentle on the stick then, not to damage the engine or prop. 6000 is the limit that SOLO calls for 30 dia blades !!
I stay with this setup, because the takeoff-power with this heavy airplane is second to none, ANDI am gentle with full throttle in flight, NEVER dive it steeply with max power. What I want to say: the setup is a compromise; good takeoff, but wrong once you gathered some speed. As long as the pilot knows what he has in his hands, I think its OK.
But I would not let another jockey fly that one
05-30-2013, 02:29 AM
#2443
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RE: MOKI RADIAL Care and Maintenence
An increase of more than 2000 RPM in flight?!?! Scary.
I stand corrected. And I would always defer to Detlef's experience and expertise.
Thanks for the perspective on potential increases in RPM while in flight! Wow!
I guess you know nothing unless you have telemetry to directly make those measurements. Now I'm very curious about my full throttle flying with my Moki 150. I get 4600 on the ground. I was "guessing" that increased to ~5000 in the air with the 24 x 18 3-blade SEP prop.
Hmmmmmm.
I stand corrected. And I would always defer to Detlef's experience and expertise.
Thanks for the perspective on potential increases in RPM while in flight! Wow!
I guess you know nothing unless you have telemetry to directly make those measurements. Now I'm very curious about my full throttle flying with my Moki 150. I get 4600 on the ground. I was "guessing" that increased to ~5000 in the air with the 24 x 18 3-blade SEP prop.
Hmmmmmm.
05-30-2013, 02:56 AM
#2444
My Feedback: (62)
RE: MOKI RADIAL Care and Maintenence
Noah, Do you have musical training? If the engine goes up one octave it has doubled in rpm! If the engine was running 4000 rpm and it goes up a fourth (close to a half octave depending on temperment) in a dive , that would be 6000 rpm! Try it on a piano. Just one note from lets say c to d would be 4000 to 4500 rpm. -Tom
05-30-2013, 01:08 PM
#2448
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: butlern
An increase of more than 2000 RPM in flight?!?! Scary.
I stand corrected. And I would always defer to Detlef's experience and expertise.
Thanks for the perspective on potential increases in RPM while in flight! Wow!
I guess you know nothing unless you have telemetry to directly make those measurements. Now I'm very curious about my full throttle flying with my Moki 150. I get 4600 on the ground. I was "guessing" that increased to ~5000 in the air with the 24 x 18 3-blade SEP prop.
Hmmmmmm.
An increase of more than 2000 RPM in flight?!?! Scary.
I stand corrected. And I would always defer to Detlef's experience and expertise.
Thanks for the perspective on potential increases in RPM while in flight! Wow!
I guess you know nothing unless you have telemetry to directly make those measurements. Now I'm very curious about my full throttle flying with my Moki 150. I get 4600 on the ground. I was "guessing" that increased to ~5000 in the air with the 24 x 18 3-blade SEP prop.
Hmmmmmm.
Yes, an amazing increase. But this is not necessarily the same with other setups, just an example HOW BIG the increase is if your pitch doesnt really suit the aircrafts speed in flight.
With a 32x20 2-blade, the increase is less (of course) but still 1400 rpm ( 4000 to 5400) at the same angle of dive, but with a higher speed on the clock (270 km/h to 240 with the fourblade, no payload carried ( clean wing).
And yes, measurement is made via telemetry. Guess who was surprised with such a readout. Me of course :-) I myself had thought that there might be a plus 1200, but not double that number (!) The pitch is too fine, but due to takeoff power I stay with that, and always careful in a dive :-)
Ah yes me measured a Moki 150 with a 24x17 SEP 3-blade at 5650 - 5700 in flight, no steep dive. Aircraft was a ScaleWIngs small LA-7 (2,3 m wingspan)
05-30-2013, 01:37 PM
#2449
My Feedback: (62)
RE: MOKI RADIAL Care and Maintenence
Detlef, Are you still working on a V-4 design? Is the moki 250 7 cylinder showing to be a fine engine? Still enjoying the perfect running of my turbulated 215. All 5 cylinders within 10F at 170 degrees F. All 5 piston surfaces without carbon deposits.
05-30-2013, 01:49 PM
#2450
RE: MOKI RADIAL Care and Maintenence
ORIGINAL: Maxam
Detlef, Are you still working on a V-4 design? Is the moki 250 7 cylinder showing to be a fine engine? Still enjoying the perfect running of my turbulated 215. All 5 cylinders within 10F at 170 degrees F. All 5 piston surfaces without carbon deposits.
Detlef, Are you still working on a V-4 design? Is the moki 250 7 cylinder showing to be a fine engine? Still enjoying the perfect running of my turbulated 215. All 5 cylinders within 10F at 170 degrees F. All 5 piston surfaces without carbon deposits.
Tom,
The Phoenix V-4 came to life for the first time december last year, and had its official debut on the Prowing exhibition last month. I am really very pleased withit.
But its no radial engine, so to anyone who wants to read more about that engine you need to look up in the RCSB-forum.
-
About the moki 250 7 cylinder : I did not hear one of the 7- cylinders running yet, dont know anybody who owns one, and so I got no idea how they perform.
