Seidel 7-70 radial: Help me decide!
12-11-2015, 10:42 AM
#927
Thread Starter
12-11-2015, 10:48 AM
#928
Thread Starter
12-11-2015, 07:58 PM
#929
Thread Starter
That it could have been the new tank was definitely a long shot. But I've now ruled that out. Again the engine wouldn't start. I'll remove the Microsens (and indeed ANY glow system) and try to get the engine started with direct battery power. Just have to wait until I can procure a suitable battery.
I'll post again in 2016.
I'll post again in 2016.
12-12-2015, 01:10 AM
#931
Thread Starter
While I ponder the battery issue, can someone explain why a 1.2V (7000mAh) battery like the one from Sanyo could be enough to light a 7-cylinder engine but not a regular 1.2V cell, for example a D-cell...or even a rechargeable 1.2V AA cell (1950mAh). I understand why these batteries would not be suitable for an onboard glow system, which requires a greater capacity, but why wouldn't ANY 1.2V battery do the job of getting the engine started once?
12-12-2015, 03:23 AM
#932
My Feedback: (3)
I am by no means an expert but here's my layman's take on it.
A 1.2V battery nominally puts out 1.2V regardless of how big the battery is. So, in essence, any size 1.2V battery can drive a glow plug. The 2 other primary factors we need to be concerned with are the capacity of the battery (mah), i.e., how long it can provide power, and its rate of power output (internal resistance), i.e., how big a thing it can drive. The capacity is like the size of your gas tank. The bigger it is, the longer it can supply power at a given rate. The internal resistance dictates how fast the power can be delivered. A V-8 engine needs more power (gas) delivered to it at a time than a straight 4 cylinder engine. Internal resistance is like the size of a spigot on a faucet. A high-power application (like a cordless power tool) needs the power to be delivered quickly (big spigot). Likewise, 7 glow plugs is a much higher power application than 1 glow plug.
A "AA" nicad has an internal resistance of about 20 mOHM. An "F" cell has an internal resistance of about 3.5 mOHM, meaning it can deliver more power faster than a "AA" cell. You could put each glow plug on its own "AA" cell and it would work fine because each cell only has to be able to deliver 1/7 of the power that an "F" cell driving all 7 plugs at once would have to deliver. However, "AA" cells are limited in their total capacity, with about 500 mah being the largest. An "F" cell, due to its low resistance, can provide much more power at a time than a "AA" (enough to drive 7 plugs instead of just 1). In addition, at 7000 mah, it would provide 7000/7 ma or 1000 ma per plug (twice the operating time of the "AA" cell) along with the convenience of not having to carry and charge 7 batteries.
The resistance (spigot size) is also why the gauge and quality (and run length) of the wire used is critical. Having a cell with a resistance of 3.5 mOHM does not do much good if the wire you use to connect it to the plugs has a resistance of 15 mOHMs, thereby closing down the size of your power spigot. 16 gauge wire has less than half the resistance of 20 gauge wire.
A 1.2V battery nominally puts out 1.2V regardless of how big the battery is. So, in essence, any size 1.2V battery can drive a glow plug. The 2 other primary factors we need to be concerned with are the capacity of the battery (mah), i.e., how long it can provide power, and its rate of power output (internal resistance), i.e., how big a thing it can drive. The capacity is like the size of your gas tank. The bigger it is, the longer it can supply power at a given rate. The internal resistance dictates how fast the power can be delivered. A V-8 engine needs more power (gas) delivered to it at a time than a straight 4 cylinder engine. Internal resistance is like the size of a spigot on a faucet. A high-power application (like a cordless power tool) needs the power to be delivered quickly (big spigot). Likewise, 7 glow plugs is a much higher power application than 1 glow plug.
A "AA" nicad has an internal resistance of about 20 mOHM. An "F" cell has an internal resistance of about 3.5 mOHM, meaning it can deliver more power faster than a "AA" cell. You could put each glow plug on its own "AA" cell and it would work fine because each cell only has to be able to deliver 1/7 of the power that an "F" cell driving all 7 plugs at once would have to deliver. However, "AA" cells are limited in their total capacity, with about 500 mah being the largest. An "F" cell, due to its low resistance, can provide much more power at a time than a "AA" (enough to drive 7 plugs instead of just 1). In addition, at 7000 mah, it would provide 7000/7 ma or 1000 ma per plug (twice the operating time of the "AA" cell) along with the convenience of not having to carry and charge 7 batteries.
The resistance (spigot size) is also why the gauge and quality (and run length) of the wire used is critical. Having a cell with a resistance of 3.5 mOHM does not do much good if the wire you use to connect it to the plugs has a resistance of 15 mOHMs, thereby closing down the size of your power spigot. 16 gauge wire has less than half the resistance of 20 gauge wire.
12-12-2015, 05:47 AM
#933
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I recently came across this thread, spent a little time with and and can certainly understand the frustration you must be experiencing and commend your persistence in trying to get this solved.
One sure method to eliminate the electrical issues is to just go out and buy 7 D size Duracell batteries and wire each directly to each plug. Break one of the leads, then twist the wires together to make the connection - no switches. Untwist to disconnect. Crude for sure, but the batteries will deliver 1.5 volts, and you will know the plugs are hot.
There may be a higher probability of finding more Seidel users on a German language r/c forum. Can't help with a link, but they must be out there. Start with a translator program. There is an older thread at RCScalebuilder on the Evolution radials. Maybe someone's there who can help.
Jim
One sure method to eliminate the electrical issues is to just go out and buy 7 D size Duracell batteries and wire each directly to each plug. Break one of the leads, then twist the wires together to make the connection - no switches. Untwist to disconnect. Crude for sure, but the batteries will deliver 1.5 volts, and you will know the plugs are hot.
There may be a higher probability of finding more Seidel users on a German language r/c forum. Can't help with a link, but they must be out there. Start with a translator program. There is an older thread at RCScalebuilder on the Evolution radials. Maybe someone's there who can help.
Jim
12-12-2015, 07:32 AM
#934
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Abu,
I watched your video two pages back and what I understand from your posts since then is that all attempts since have had the same result. I know it is stating the obvious, but for an engine to run, it needs fuel, air, and spark/fire. Your video shows that you don't even get a pop... You get nothing as if you didn't have one or more of the three necessaries.
Of course you've got air, and it sounds like you have taken out the glow plugs connected to their leads and they are glowing with some degree of brightness, is that correct? You've checked them all at the same time, right? As for fuel, besides you stating that fuel is dripping from your ring, are the plugs wet when you take them out?
I wish I had a specific AHA to give you, but your problem has to be no fuel, no air, or no fire. The fact that it is a glow engine rules out ignition system firing problems.
Lars
I watched your video two pages back and what I understand from your posts since then is that all attempts since have had the same result. I know it is stating the obvious, but for an engine to run, it needs fuel, air, and spark/fire. Your video shows that you don't even get a pop... You get nothing as if you didn't have one or more of the three necessaries.
Of course you've got air, and it sounds like you have taken out the glow plugs connected to their leads and they are glowing with some degree of brightness, is that correct? You've checked them all at the same time, right? As for fuel, besides you stating that fuel is dripping from your ring, are the plugs wet when you take them out?
I wish I had a specific AHA to give you, but your problem has to be no fuel, no air, or no fire. The fact that it is a glow engine rules out ignition system firing problems.
Lars
12-12-2015, 08:26 AM
#935
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Abufletcher
What has worked well for me is just wiring together 4 D cell rechargeable 10,000 milliamp batteries to 2.4 volts switched with a 30 amp toggle. That gives you a 40 amp battery capacity which you need to glow all seven plugs at once. Those plugs can draw almost 3 amps each on start up and unless they are glowin' you ain't startin' I also recommend using a 24 volt starter for the first start when cold.
After messing with these engines for the past 3 years I can just about guarantee you that if you try this it will start and run.
Tom
What has worked well for me is just wiring together 4 D cell rechargeable 10,000 milliamp batteries to 2.4 volts switched with a 30 amp toggle. That gives you a 40 amp battery capacity which you need to glow all seven plugs at once. Those plugs can draw almost 3 amps each on start up and unless they are glowin' you ain't startin' I also recommend using a 24 volt starter for the first start when cold.
After messing with these engines for the past 3 years I can just about guarantee you that if you try this it will start and run.
Tom
12-12-2015, 08:58 AM
#936
Like RBACONS was saying there is capacity and there is flow. If you have one water hose and want to water the front and back yard at the same time, you will only have trickels instead of a spray. Your house has the capacity to water as long as the city lets you but dividing once it hits the house pipes limits how fast you can use it. House, unlimited capacity, use limited. Get 4 glow sticks; start on 4 cylinders and then move sticks to cold cylinders should get it running.
12-12-2015, 09:51 AM
#937
My Feedback: (3)
Tom,
I'm sure the 4 D cells work just fine. And you have excess capacity. The only down side is space and weight. The 4 D cells weigh in at about 23 oz (1 1/2 lbs) whereas the F cell is just under 8 oz. That's a lot of extra dead weight to be carrying. Also, while you might have 40,000 mah of capacity, that does not say anything about the ability to deliver 21 Amps to the plugs. That's current, not capacity.
I'm sure the 4 D cells work just fine. And you have excess capacity. The only down side is space and weight. The 4 D cells weigh in at about 23 oz (1 1/2 lbs) whereas the F cell is just under 8 oz. That's a lot of extra dead weight to be carrying. Also, while you might have 40,000 mah of capacity, that does not say anything about the ability to deliver 21 Amps to the plugs. That's current, not capacity.
12-12-2015, 10:53 AM
#939
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Rbacons,
You are right about the current and capacity. After experimenting with onboard glow power for several years this is the set up that works best for me. Not just for the evo 77 but the evo 99 and asp 400. My airplanes need the weight in the tail anyway to get the correct cg with the heavy radial up front so the battery weight is useful. I switch the battery on with a servo to a toggle switch for start up and low throttle settings. I love these engines and they are joy to fly in large airplanes but they do require more tinkering and maintenance. But when I do a low pass and that radial goes rumbling by I still get goose bumps. Not many things can do that to a 70 year old guy like me! It is close as I can get to the days I flew my Travelair 4000 with the Lycoming R 680 growling up front.
Anyway, I know my glow set up is not the only way to do it but it works great for me and I think it might be worth Abufletcher giving it a try.
Tom
You are right about the current and capacity. After experimenting with onboard glow power for several years this is the set up that works best for me. Not just for the evo 77 but the evo 99 and asp 400. My airplanes need the weight in the tail anyway to get the correct cg with the heavy radial up front so the battery weight is useful. I switch the battery on with a servo to a toggle switch for start up and low throttle settings. I love these engines and they are joy to fly in large airplanes but they do require more tinkering and maintenance. But when I do a low pass and that radial goes rumbling by I still get goose bumps. Not many things can do that to a 70 year old guy like me! It is close as I can get to the days I flew my Travelair 4000 with the Lycoming R 680 growling up front.
Anyway, I know my glow set up is not the only way to do it but it works great for me and I think it might be worth Abufletcher giving it a try.
Tom
12-12-2015, 12:07 PM
#940
Thread Starter
One sure method to eliminate the electrical issues is to just go out and buy 7 D size Duracell batteries and wire each directly to each plug. Break one of the leads, then twist the wires together to make the connection - no switches. Untwist to disconnect. Crude for sure, but the batteries will deliver 1.5 volts, and you will know the plugs are hot.
There may be a higher probability of finding more Seidel users on a German language r/c forum. Can't help with a link, but they must be out there. Start with a translator program.
I have in the past visited a German RC forum but at this point there are probably more Seidel/UMS/Evolution engines being sold outside Germany. BTW, there is this RCU thread on radial engines:http://www.rcuniverse.com/forum/glow...l-engines.html
I appreciate all of the advice and suggestions, guys.
12-12-2015, 12:19 PM
#941
Thread Starter
My understanding (from a previous explanation on another thread) is that mAh is capacity (i.e. the "size of the tank") while voltage is like the diameter of the pipe (i.e. more volts = more electricity flowing). I don't understand how "battery resistance" comes into this. And despite the fact that I speak German, Spanish, English, and some Japanese, Russian, Arabic, and Portuguese, "amps" is completely Greek to me. 
How would I wire four D cells together? Also, for test purposes would ordinary non-rechargeable alkaline batteries work?
How would I wire four D cells together? Also, for test purposes would ordinary non-rechargeable alkaline batteries work?
12-12-2015, 02:13 PM
#942
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The 7 D cell setup uses a single D size non-rechargeable alkaline battery (from the drug or hardware store) for each plug. This is for bench testing only and is definitely a Rube Goldberg setup.
In thinking about one way to do this, tape the 7 batteries together side by side all positives up and in a line. Solder a heavy #16 lead across and to each of the negative posts. Extend the tail about 18-24 inches and strip the end back about an inch. Then to each positive post solder an 18 inch lead and terminate at each plug center post with whatever connector you are using (even wheel collar with wire soldered). Finish by attaching a lug to the engine case using #16 wire. Strip other end and make long enough to reach the stripped negative from the batteries. To complete the circuit just twist the wires together. To turn off untwist.
This method gives you the full capacity of a fresh D cell to each plug.
I was thinking of this thread: http://www.rcscalebuilder.com/forum/...TID=18951&PN=6
Last post on bottom of page: http://www.rcscalebuilder.com/forum/...37&PN=4&TPN=10
Going through the threads on big radial warbirds should turn up Seidel/Evolution installations. You could contact those users.
Do keep posting here, and good luck. Jim
In thinking about one way to do this, tape the 7 batteries together side by side all positives up and in a line. Solder a heavy #16 lead across and to each of the negative posts. Extend the tail about 18-24 inches and strip the end back about an inch. Then to each positive post solder an 18 inch lead and terminate at each plug center post with whatever connector you are using (even wheel collar with wire soldered). Finish by attaching a lug to the engine case using #16 wire. Strip other end and make long enough to reach the stripped negative from the batteries. To complete the circuit just twist the wires together. To turn off untwist.
This method gives you the full capacity of a fresh D cell to each plug.
I was thinking of this thread: http://www.rcscalebuilder.com/forum/...TID=18951&PN=6
Last post on bottom of page: http://www.rcscalebuilder.com/forum/...37&PN=4&TPN=10
Going through the threads on big radial warbirds should turn up Seidel/Evolution installations. You could contact those users.
Do keep posting here, and good luck. Jim
12-12-2015, 06:31 PM
#943
My Feedback: (3)
My understanding (from a previous explanation on another thread) is that mAh is capacity (i.e. the "size of the tank") while voltage is like the diameter of the pipe (i.e. more volts = more electricity flowing). I don't understand how "battery resistance" comes into this.
12-13-2015, 03:39 AM
#944
Thread Starter
Quick test: Ordinary 1.5V DD cell, some store-bought wires with alligator clips, and one of the original UMS cables = GOOD STRONG GLOW. This seems a bit stronger than I was getting through the glow system. Note: The wires with the alligator clip are much thinner than the ones for the glow system. Maybe I'll solder some electrical tabs onto the terminals of the 7 DD batteries and use these wires with clips for the test run (attempt). Now to work out the logistics.
12-13-2015, 07:31 AM
#945
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Glow that bright to all 7 plugs will certainly eliminate any electrical problem. Soldering the wires directly to the battery is easy and eliminates conductivity questions about springs and clips.
12-13-2015, 07:34 AM
#946
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Wow that plug connector (UMS cable) is very close to the hex of the plug.
I wonder if they are able to be pushed on to far? And that would be a
short. A easy path for the current to go and bypass the filament.
And short drains your power system very fast.
And can be dangerous to with systems (voltage regulators and batteries)
over heating.
I realize you may already know all this but it may help another modeler.
So much for taking a break.
I wonder if they are able to be pushed on to far? And that would be a
short. A easy path for the current to go and bypass the filament.
And short drains your power system very fast.
And can be dangerous to with systems (voltage regulators and batteries)
over heating.
I realize you may already know all this but it may help another modeler.
So much for taking a break.
12-13-2015, 08:30 AM
#947
Thread Starter
As far as taking a break, well, I guess the DD batteries setup might allow me to try starting the engine. And if I can get that to work, it'll be at least a week (and more likely three) before I scrabble together a functional glow system for the model (tested first on the stand). And then if I can get the engine to consistently start time after time, then I can put the whole kit and caboodle back into the model. Then test the whole setup all over again. So yeah it'll definitely be 2016 before this gets all sorted out.