UMS Evolution Radial Care and Operation
#1251
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I am quite happy with my 9-99 in my 87 inch Ziroli Stearman. At 30 pounds it gets off the ground in less than 50 feet and flies very realistically just like a full size Stearman but faster. I am getting 4900 rpm on a 24X12 Xoar prop. I get only 4300 rpm during the first minute of running but it increases after I warm it up and go back and forth from idle to WOT several times. I am using on board ignition which kicks in at about i/2 throttle. It idles great at 1700 rpm. I have followed all of Maxam's advice except for the use of the aquarium pump and the engine continues to seem very 'buttery smooth" when turned over by hand. I use 20 cc of air-tool oil and 5cc of after-run oil at the end of each flying day. I am wondering if Maxam has any additional advice regarding laying these engines up for the winter.
#1253
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I solved all of the after run oil issues...I purchased a CH ignition for the 7-77 and will run it on gas. I installed the ignition today, hopefully get to run it this weekend.
The 77 will be going in a 1/4 scale Fleet bi-plane.
The 77 will be going in a 1/4 scale Fleet bi-plane.
#1257
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Best you check with Adrian at CH for a price. I obtained somewhat of a pre-production unit as he has not yet finalized the box to house the electronics. They are a tad expensive!
#1258
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Ran the 77 on gas/ignition today. (32:1) Started right up, glow carb worked very well, but still have to play around with the adjustments...,spitting a fair bit of oil...at least the innards should be well lubricated.
Turned a JC 22-12 at 56-5700, transition is very crisp, no hesitation, idle at about 17-18--, but only have approx 20 mins. on the engine on glow. RPM, high and low, should get better with time.
Ignition unit was quite expensive, but to me, well worth it...I'm not a glow fuel fan...lol
Turned a JC 22-12 at 56-5700, transition is very crisp, no hesitation, idle at about 17-18--, but only have approx 20 mins. on the engine on glow. RPM, high and low, should get better with time.
Ignition unit was quite expensive, but to me, well worth it...I'm not a glow fuel fan...lol
#1261
My Feedback: (3)
My experience is glow carbs can't regulate accurately enough in the lean region for gasoline, but maybe things have changed with modern glow carbs. Methanol carries more oxygen than gas does does, as such the carb runs richer than it would as adjusted for gas(which needs more air).
#1263
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But I'm no expert ...
#1265
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I never thought that methanol has a higher flame speed than gasoline. I've always thought it actually was slower. And gasoline has more BTU content (heat) per unit volume than methanol. One of the reasons race cars use it is because it's safer in an accident. I could be wrong, as I'm not an expert (remember experts said Obamacare would save us all $2500 per year on our premiums), but there's a simple reason you get more power out of a methanol based engine. It's because you run it richer. And you run it richer because methanol carries more of it's own oxygen chemically than gasoline, so you can. So even though gasoline carries more energy, you have to mix it with so much air to achieve proper fuel/air ratio that the mixture far leans out (less gas=fewer BTU's) compared with methanol. That's why your car, running farm-welfare fuel, gets crummier mileage. So, in a given unit amount of time, methanol is processing more BTU's per minute than gasoline, thus more "perceived" power. Power always has a time component. For example, HPower=torque x rpm/5252 (a constant). The rpm has MINUTE in it, thus the time component. So, measuring the power produced by gasoline must also have a time component.
#1266
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To answer a few of the questions posted here....
I converted the 77 to gas as everything else I have is gas @ 32:1 so only 1 gas can. Haven't use glow fuel for years, other than a couple of tanks when first running the engine.
Adrian made no mention of changing the carb "O" rings, I've only run a couple of 16 oz. tanks through and no issues.....yet. Having to lean the needles quite a bit on gas.
The timing set up is comprised of 3 parts, 1...the sensor ring which is a press fit over the front snout of the crankcase.
2..the prop drive washer is 2 parts, the drive washer and a magnet ring which is set-screwed to the prop driver once the timing has been set...straight forward job.
The only drawback that I can see is if you have a prop strike, and the drive washer moves, you have to go through the timing procedure again. Good incentive to keep the prop off the ground.
The ignition box is a little bulky as it has 7 plug leads and whatever else is in there. When Adrian finalizes the box it may be smaller. Mine is serial #5. When you first look at the magnet ring it has eight magnets, but is a 7 cyl engine. Magnet # 8 is to re-set the firing sequence in the computer. 1-3-5-7-2-4-6..repeat
As for the price, please contact Adrian at CH....it is not cheap!!!
This 77 will be going in a 1/4 scale Fleet model 2, which will be one of my winter projects. More power than I need, but that is what the left stick is for.
I bought the radial for the looks and sound, went to gas, not because it may have or not have more or less power, but because gas is all I do.
I'll try to post a picture soon.
Cheers,
Dave.
I converted the 77 to gas as everything else I have is gas @ 32:1 so only 1 gas can. Haven't use glow fuel for years, other than a couple of tanks when first running the engine.
Adrian made no mention of changing the carb "O" rings, I've only run a couple of 16 oz. tanks through and no issues.....yet. Having to lean the needles quite a bit on gas.
The timing set up is comprised of 3 parts, 1...the sensor ring which is a press fit over the front snout of the crankcase.
2..the prop drive washer is 2 parts, the drive washer and a magnet ring which is set-screwed to the prop driver once the timing has been set...straight forward job.
The only drawback that I can see is if you have a prop strike, and the drive washer moves, you have to go through the timing procedure again. Good incentive to keep the prop off the ground.
The ignition box is a little bulky as it has 7 plug leads and whatever else is in there. When Adrian finalizes the box it may be smaller. Mine is serial #5. When you first look at the magnet ring it has eight magnets, but is a 7 cyl engine. Magnet # 8 is to re-set the firing sequence in the computer. 1-3-5-7-2-4-6..repeat
As for the price, please contact Adrian at CH....it is not cheap!!!
This 77 will be going in a 1/4 scale Fleet model 2, which will be one of my winter projects. More power than I need, but that is what the left stick is for.
I bought the radial for the looks and sound, went to gas, not because it may have or not have more or less power, but because gas is all I do.
I'll try to post a picture soon.
Cheers,
Dave.
Last edited by mogman; 10-13-2014 at 02:38 PM.
#1267
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[QUOTE=Pull Up Now!;11898938]I One of the reasons race cars use it is because it's safer in an accident. I could be wrong, as I'm not an expert ...
Gasoline was used at the Indianapolis 500 until 1964, when a horrific crash & fireball in the first turn of lap one took the life of two drivers, including the really popular Eddie Sachs. They switched to methanol because it is much less volatile than gasoline (has a lower vapor pressure), has a much higher "lower flammability limit" (6% in air vs 1.4% for gas), can be put out with water, etc. - hence safer. These days they run ethanol because of the political sensibilities of corn ethanol in the Midwest.
The dirt track guys (racers) are a good source of information on the relative merits of gasoline, methanol, and nitromethane. Here's a typical source that states methanol is good for about 20% more power than gasoline (for a given displacement). I like the comment 'I guess the old saying is true. "Gasoline is for washing parts, alcohol is for drinking and nitro is for racing."'.
Gasoline was used at the Indianapolis 500 until 1964, when a horrific crash & fireball in the first turn of lap one took the life of two drivers, including the really popular Eddie Sachs. They switched to methanol because it is much less volatile than gasoline (has a lower vapor pressure), has a much higher "lower flammability limit" (6% in air vs 1.4% for gas), can be put out with water, etc. - hence safer. These days they run ethanol because of the political sensibilities of corn ethanol in the Midwest.
The dirt track guys (racers) are a good source of information on the relative merits of gasoline, methanol, and nitromethane. Here's a typical source that states methanol is good for about 20% more power than gasoline (for a given displacement). I like the comment 'I guess the old saying is true. "Gasoline is for washing parts, alcohol is for drinking and nitro is for racing."'.
Last edited by redball8; 10-13-2014 at 02:42 PM. Reason: fixed the link
#1269
My Feedback: (3)
I love this radial ignition experiment. Want one! But...I'm still trying to wrap my head around EIGHT magnets. Are you sure you didn't count #1 twice? Why wouldn't #1 be #8? 1,3,5,7,2,4,6,1,3,5,7,2,4,6,1,3,5,7,2,4,6,1....... etc? Also, have you checked to see if the ignition module is truly firing in sequence? Or are more than one plugs firing at the same time? I would assume that each plug fires once when it should, and a second time harmlessly on the exhaust stroke. Because the unit doesn't know if a cylinder is on compression or exhaust. More detailed info would be great.
#1270
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The engine runs very smoothly. The #8 magnet is to tell the ignition computer to start the firing sequence again at #1.
When I talked to Adrian, that's what he told me.
Magnets for # 1-2-3-4-5-6-7 are "north" magnets, the #8 is a "south "( or vise-versa) When you set up the timing using the provided RCXL timing kit, you turn the magnet ring c/c wise the magnets for all 7 cyls turn on a green light, the #8 magnet turns on a red light.The computer now knows it has fired all cyls. Now time to start all over again.
Yes, there is a wasted spark.
Adrian set up the ignition to run on a 3 cell lipo...7.4-12.0v. I tried with a 2 cell 6.6 life, ran great, and Adrian says that will work very well. He also initially recommended 20:1 mix, but told me that produces a lot of exhaust mess, so he said go to 32:1.
Cheers,
Dave.
All I can say it works very well, and I am very happy with it.
When I talked to Adrian, that's what he told me.
Magnets for # 1-2-3-4-5-6-7 are "north" magnets, the #8 is a "south "( or vise-versa) When you set up the timing using the provided RCXL timing kit, you turn the magnet ring c/c wise the magnets for all 7 cyls turn on a green light, the #8 magnet turns on a red light.The computer now knows it has fired all cyls. Now time to start all over again.
Yes, there is a wasted spark.
Adrian set up the ignition to run on a 3 cell lipo...7.4-12.0v. I tried with a 2 cell 6.6 life, ran great, and Adrian says that will work very well. He also initially recommended 20:1 mix, but told me that produces a lot of exhaust mess, so he said go to 32:1.
Cheers,
Dave.
All I can say it works very well, and I am very happy with it.
Last edited by mogman; 10-14-2014 at 08:18 AM.
#1271
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#1273
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yeah, it does look great. I like the crude home-made look to the box too. I see 3 connections....must be power, hall sensor, and rpm? I hate to keep harping on the 8 magnets, but I have to ask if that 8th magnet with the opposite polarity is co-located right next to the 7th magnet (at the same place degree-wise)?
#1274
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Yes, 3 connectors, sensor, battery and tach.
The 8th magnet is located between the last magnet in the firing order...#6, and the first in the firing order...#1..so as soon as #6 fires, #8 triggers the end of the rotation and sets up #1 to fire.
Cheers,
Dave.
The 8th magnet is located between the last magnet in the firing order...#6, and the first in the firing order...#1..so as soon as #6 fires, #8 triggers the end of the rotation and sets up #1 to fire.
Cheers,
Dave.
#1275
My Feedback: (3)
Dave, that makes MUCH more sense now. The 8th magnet doesn't represent it's own equal segment, but rather serves as a warning #1 is coming. The module gets the warning, but still doesn't know if it's exhaust or compression that coming, but it doesn't matter. Like a single or a twin, it just fires anyway. Thanks for sticking with me on this detail. I've got a request for quote in to Adrian on one of these babies. Also, one for a flat four 4-stroke. Pegasus 320.