RcExcel Ignition version - DLE 20
03-05-2014, 09:33 AM
#51
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Truckracer:
True about the change out of ignition modules. There are numerous resources to upgrade your ignition. Tower is probably the most expensive at 75.00. However if you do research you can find the CH ignition among RCexl online for around 50.00. Milehigh RC has some for around that price.
It is always a good idea to have a spare ignition in your "fly" kit or tool box.
Glenn Williams
True about the change out of ignition modules. There are numerous resources to upgrade your ignition. Tower is probably the most expensive at 75.00. However if you do research you can find the CH ignition among RCexl online for around 50.00. Milehigh RC has some for around that price.
It is always a good idea to have a spare ignition in your "fly" kit or tool box.
Glenn Williams
03-05-2014, 09:37 AM
#52
Not really the case at all because when flying, even doing 3D, you are well above the RPM where the ignition curve "kicks in". The problem is really just in transition to just above idle or getting the engine to settle back into a good idle. Earlier I gave an example of landing where you are on approach and just about ready to touch down .... but you need just a tiny bit of power to stretch the landing a bit or to aid the flair. That tiny bit of throttle will allow the ignition curve to kick in and you get a burst of power rather than the tiny bit you wanted. Then the dang engine won't settle back to a nice idle for a good touch down. Leads to frustration and some really sloppy landings.
Some people never experience the problem because they never use the throttle, or at least they don't use it in a way that allows the problem to happen. Some others wouldn't know a good running engine from a bad one and likewise they would never experience the problem because they could not identify it.
As others have, with very careful adjustments and a slow enough idle you can sort of work around the problem but it is always there to some degree. It will get you and p*ss you off when you least expect it. The problem can go away completely for under $50 for people that have the older modules.
Some people never experience the problem because they never use the throttle, or at least they don't use it in a way that allows the problem to happen. Some others wouldn't know a good running engine from a bad one and likewise they would never experience the problem because they could not identify it.
As others have, with very careful adjustments and a slow enough idle you can sort of work around the problem but it is always there to some degree. It will get you and p*ss you off when you least expect it. The problem can go away completely for under $50 for people that have the older modules.
03-05-2014, 11:21 AM
#53
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Hey TR, I wish you would stop beating around the bush, so to speak, and tell us how you really feel.
In all seriousness thanks for your candid input. I, for one, totally agree.
In all seriousness thanks for your candid input. I, for one, totally agree.
03-05-2014, 12:00 PM
#54
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I haven't used one of the RCXP units yet but I've never heard a bad report about them. That would probably be my choice for low cost and good support after the sale. We're talking RCextremepower here. Of course there are the Rcexl and CH units that have a proven track record and are available at a wide range of prices. Just about any unit but the #4 would be my choice. Any of the standard, off the shelf units will have an acceptable curve.
03-05-2014, 12:49 PM
#55
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03-05-2014, 01:52 PM
#56
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X2 on TR's comments regarding "tickling" the throttle to extend a glide, though I rarely run into that, and yes, I play with the 3D stuff quite a bit.
Sometimes this issue can be tracked back to throttle arm geometry and/or radio setup though. The #4 module did have trouble, but I think it's also really taken it on the chin for a ton of stuff it has/had nothing to do with. It's really easy for some low gas time pilots to point here for trouble. That's why I don't argue the point much any more. If it's making you crazy, get a different one. That's one more thing you can cross off the list of potential problems. It's not really just throwing parts at a problem either. Trying to figure out whether your "hang" issue is heat related, mixture related, throttle setting related, whatever, with little or no experience to base decisions on, well, it's not hard to see how some get so frustrated! They're VERY closely related, and that "step" isn't helping a darn thing.....
X2 on the RCXP suggestion as well. They're 45.00 as you don't need the sensor or bracket. The Rcexl sensor will plug right in to the Rcxp module. -Al
Sometimes this issue can be tracked back to throttle arm geometry and/or radio setup though. The #4 module did have trouble, but I think it's also really taken it on the chin for a ton of stuff it has/had nothing to do with. It's really easy for some low gas time pilots to point here for trouble. That's why I don't argue the point much any more. If it's making you crazy, get a different one. That's one more thing you can cross off the list of potential problems. It's not really just throwing parts at a problem either. Trying to figure out whether your "hang" issue is heat related, mixture related, throttle setting related, whatever, with little or no experience to base decisions on, well, it's not hard to see how some get so frustrated! They're VERY closely related, and that "step" isn't helping a darn thing.....
X2 on the RCXP suggestion as well. They're 45.00 as you don't need the sensor or bracket. The Rcexl sensor will plug right in to the Rcxp module. -Al
03-05-2014, 02:09 PM
#57
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"Sometimes this issue can be tracked back to throttle arm geometry and/or radio setup though." - ahicks
Al - probably LESS has been done to inform and educate modelers on this aspect alone than all the other myriad of things we have to learn. Poor documentation, ever worse owners manuals, and the fact that FEW pilots try to figure out how to get a Walbro to act anywhere near linearly for their engines all combine to make us just flat pass by.
Carb arm geometry/servo arm geometry and radio "curves" can really make these little carbs and engines run like sewing machines, but I think the vast majority of users just bolt 'n go.
Great reminder, Al !!!
Al - probably LESS has been done to inform and educate modelers on this aspect alone than all the other myriad of things we have to learn. Poor documentation, ever worse owners manuals, and the fact that FEW pilots try to figure out how to get a Walbro to act anywhere near linearly for their engines all combine to make us just flat pass by.
Carb arm geometry/servo arm geometry and radio "curves" can really make these little carbs and engines run like sewing machines, but I think the vast majority of users just bolt 'n go.
Great reminder, Al !!!
03-05-2014, 03:28 PM
#59
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I always accused a good friend of mine of having "toggle switch" throttles as they were almost always set up with the wrong differential at the low end. I couldn't imagine one of those setups with a DLE20 and a #4 ignition. Strange, the rest of the linkages on his planes were set up so well. On the throttle he was just happy if the carb arm moved when he moved the throttle stick. I think many people fall into that category.
03-05-2014, 03:56 PM
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I may be confused but, the way I understand it a direct replacement for our DLE 20 ignition module is "RCXP single CM6 ignition without sensor and sensor bracket" and it will work with the sensor that comes on the motor. If I am wrong please correct me.
03-05-2014, 06:33 PM
#63
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For the uninitiated, looking at the drawing posted by w8ye for the first time (or the 100th), going what the ????? are they talking about?
Notice that the servo arm (w/throttle stick at idle) starts out pointed nearly straight at the end of the closed throttle arm. Suggest that if you start there using arms that are roughly the same length, your battle with this issue will be mostly won. From there things will just fall into place with your linkage setup.
Notice that in the 3rd part, the servo has moved 40% of it's travel (not quite half stick) and only pulled the throttle open 9 degrees (maybe 10% of it's travel). That's because this carb design we're working with is not linear like the glow engines we're used to. This carb has pretty much all of it's available power on tap at just a little past half open? Yes, it's ALL DONE, with very little more power or rpms available, at maybe 60% open. What this means is that when you're trying to "tickle" that carb to extend the glide, the amount of carb arm travel necessary is really tiny! To have that tiny amount of travel available for us to use accurately we have to do something to allow it. Using conventional servo linkage setup like on an elevator or aileron is simply not going to cut it.
There's a LOT to be learned/accomplished here for those that don't care for that on-off "throttle switch" effect, especially if you're used to using a little throttle to help check your descent in the flair and all you can manage is a big balloon every time you try. If you're having trouble, or you just don't get it, I didn't either at first, but the more I demanded of my planes, the more it became clear I was going to need to figure this out. In the end, it was time well spent..... Ask questions! Nobody is laughing here, I can assure you....
Not going to argue that this must be done using your throttle linkage (though personally, I think it's a great place to start). This drawing illustrates pretty clearly what it is you're trying to accomplish with a throttle curve though.
Last point, this (as well as the idle hang issues) doesn't only apply to just DLE 20's or all 20's. It's pretty typical of gassers in general. -Al
Notice that the servo arm (w/throttle stick at idle) starts out pointed nearly straight at the end of the closed throttle arm. Suggest that if you start there using arms that are roughly the same length, your battle with this issue will be mostly won. From there things will just fall into place with your linkage setup.
Notice that in the 3rd part, the servo has moved 40% of it's travel (not quite half stick) and only pulled the throttle open 9 degrees (maybe 10% of it's travel). That's because this carb design we're working with is not linear like the glow engines we're used to. This carb has pretty much all of it's available power on tap at just a little past half open? Yes, it's ALL DONE, with very little more power or rpms available, at maybe 60% open. What this means is that when you're trying to "tickle" that carb to extend the glide, the amount of carb arm travel necessary is really tiny! To have that tiny amount of travel available for us to use accurately we have to do something to allow it. Using conventional servo linkage setup like on an elevator or aileron is simply not going to cut it.
There's a LOT to be learned/accomplished here for those that don't care for that on-off "throttle switch" effect, especially if you're used to using a little throttle to help check your descent in the flair and all you can manage is a big balloon every time you try. If you're having trouble, or you just don't get it, I didn't either at first, but the more I demanded of my planes, the more it became clear I was going to need to figure this out. In the end, it was time well spent..... Ask questions! Nobody is laughing here, I can assure you....
Not going to argue that this must be done using your throttle linkage (though personally, I think it's a great place to start). This drawing illustrates pretty clearly what it is you're trying to accomplish with a throttle curve though.
Last point, this (as well as the idle hang issues) doesn't only apply to just DLE 20's or all 20's. It's pretty typical of gassers in general. -Al
Last edited by ahicks; 03-05-2014 at 06:42 PM.
03-05-2014, 07:03 PM
#64
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Good info ahicks! I'd like to add that every butterfly type carb, regardless of what it is mounted on has similar non-linear characteristics. This would include everything from a chainsaw to an automobie. Tiny throttle changes at or near low throttle have a much greater affect on power than large changes from say half throttle on up. I cringe when I hear someone say this carb or that carb has these characteristics when as you stated they all do! Large carb bores exhibit this problem more than small ones, especially if the carb is considered large for the engine it is mounted on.
03-06-2014, 05:12 AM
#65
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Regarding throttle linkage setups....in the sticky, MTK posts info from Tired Old Man, who is legendary in his expertise and knowledge of these things. Some history is in order, please bear with me....when the GROSS non linearity of two-cycle carbs was profoundly affecting very serious applications for DoD projects, we (the industry of "remote control") did not have 1/8th of the transmitter capabilities, nor servo reliability of todays' stuff. Consequently, things like "differential" in elevator travel or aileron had to be done mechanically. Geometry was the cure. Remember, a FANCY tx system couldn't even alter the total travels of servos on EITHER end, much less shape response during their transit.
Fast forward about 30 years - YES - THIRTY - and we have today the identical struggles, and able to build on the mechanical work of those who have come before.
Now a really, really well-tuned throttle can be had quite simply, assuming one has a good TX system with a multi-point throttle curve and adjustable end points, and trim step authority. If you have that, (like I do, I use the Hitec Aurora 9, terrific system), here's a bulletproof, and quite simple process.
1. Set up TX - no curves, 100% travels, normal trim step. Measure the NEEDED total movement of the CARB throttle arm, fully closed to fully open and note that number. That is the target of total travel you will need from the SERVO, using whatever hole on the servo arm will give you that travel that is closest to the shaft of the servo.
2. Set throttle servo to half stick (no trim used, just center stick travel)
3. Move Carb arm to HALF travel and hold in place.
4. Setup mechanical linkage length to attach servo hole to throttle arm outermost hole (or close to it); use the servo hole that is CLOSEST to shaft that gives you the measured travel at the carb arm that is needed for full movement. That may not be the "inner most hole" on the servo arm.
5. Follow the rest of the detail in the sticky from MTK's quoted post of TOM, but THIS time, use the transmitter. Setup a VERY slow opening curve that results in nearly fully-open throttle arm at half-stick on the curve ( I've found it to be a little more like 75% open at half stick for my tastes), and you're good to go.
The solid advantage to this electronic configuration is that it gives the user TOTAL flexibility to control how rapidly the throttle opens ( the X axis of the curve) and how MUCH it opens (the Y axis of the curve). The benefits of this ability let one fine tune how the power "feels", and actually lets you adjust for power affecting changes like props or aircraft weight, with the added benefit of YOU being able to tweak it like you like it.
If you have multiple curves available (Flight Modes), it's even better, because you can preset subtle throttle curve changes on the ground and switch them in the air.
As others have said - THE most valuable thing to know is that the bottom one-third of that carb plate rotation is where the action is. That's where all your tweaking for stick position up to nearly half stick should be.
Technology can be your friend and ally. Do not fear it.
Fast forward about 30 years - YES - THIRTY - and we have today the identical struggles, and able to build on the mechanical work of those who have come before.
Now a really, really well-tuned throttle can be had quite simply, assuming one has a good TX system with a multi-point throttle curve and adjustable end points, and trim step authority. If you have that, (like I do, I use the Hitec Aurora 9, terrific system), here's a bulletproof, and quite simple process.
1. Set up TX - no curves, 100% travels, normal trim step. Measure the NEEDED total movement of the CARB throttle arm, fully closed to fully open and note that number. That is the target of total travel you will need from the SERVO, using whatever hole on the servo arm will give you that travel that is closest to the shaft of the servo.
2. Set throttle servo to half stick (no trim used, just center stick travel)
3. Move Carb arm to HALF travel and hold in place.
4. Setup mechanical linkage length to attach servo hole to throttle arm outermost hole (or close to it); use the servo hole that is CLOSEST to shaft that gives you the measured travel at the carb arm that is needed for full movement. That may not be the "inner most hole" on the servo arm.
5. Follow the rest of the detail in the sticky from MTK's quoted post of TOM, but THIS time, use the transmitter. Setup a VERY slow opening curve that results in nearly fully-open throttle arm at half-stick on the curve ( I've found it to be a little more like 75% open at half stick for my tastes), and you're good to go.
The solid advantage to this electronic configuration is that it gives the user TOTAL flexibility to control how rapidly the throttle opens ( the X axis of the curve) and how MUCH it opens (the Y axis of the curve). The benefits of this ability let one fine tune how the power "feels", and actually lets you adjust for power affecting changes like props or aircraft weight, with the added benefit of YOU being able to tweak it like you like it.
If you have multiple curves available (Flight Modes), it's even better, because you can preset subtle throttle curve changes on the ground and switch them in the air.
As others have said - THE most valuable thing to know is that the bottom one-third of that carb plate rotation is where the action is. That's where all your tweaking for stick position up to nearly half stick should be.
Technology can be your friend and ally. Do not fear it.
Last edited by Bob Pastorello; 03-06-2014 at 08:21 AM. Reason: Additional comment
03-06-2014, 10:34 AM
#66
I used to just use a long arm on the throttle shaft of the carb, set up the linkage for full and low throttle, and then use some exponential in the transmitter on the throttle channel.
Worked fine. Then I set up a couple of planes with the diagram as shown by W8YE. I didn't like it because it made the throttle too insensitive right at idle. The idle trims didn't work well, and the idle didn't seem as stable/reliable even though I had a tight linkage setup. I went back to using either exponential or throttle curves myself.
AV8TOR
Worked fine. Then I set up a couple of planes with the diagram as shown by W8YE. I didn't like it because it made the throttle too insensitive right at idle. The idle trims didn't work well, and the idle didn't seem as stable/reliable even though I had a tight linkage setup. I went back to using either exponential or throttle curves myself.
AV8TOR
03-06-2014, 10:58 AM
#67
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The diagram posted by W8YE shows an extreme amount of differential. Long before that diagram was going around, I was using mechanical differential but not as much as shown in the diagram. With a bit less differential the trims and idle cut-off still work in a normal manner. On the last few airplanes that have transmitters with throttle curves, I'm back to just setting up the linkages with fairly equal carb and servo arm lengths and everything set at 90 degrees at center. I just dial in the desired throttle curve at the transmitter. Works great and is more adjustable than a strictly mechanical setup. Using quality throttle servos, I see no downside to doing it this way.
03-06-2014, 01:02 PM
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Here's a guy whose carb is well-adjusted....demonstrates a LOT of that "full on">"full off" style....by necessity.... 
Enjoy - and turn your speakers UP so you can hear how well tuned.... https://www.youtube.com/watch?v=2xrtHUUjQDo
Enjoy - and turn your speakers UP so you can hear how well tuned.... https://www.youtube.com/watch?v=2xrtHUUjQDo
03-06-2014, 11:15 PM
#70
Senior Member
Conrod, there's a BUNCH of guys flying with that original "single step" module. The downside is it's pickier on it's adjustments.
Re: the high idle hang, many (most?) times, that's due to a lean low speed mixture, or an idle speed setting that's been set a little too close to the "step" (2500rpm+-).
Point being, fly it and see what you think. If the high idle thing is an issue that ends up being a headache, THEN replace the module. Don't replace it just because there's a potential problem. It's not THAT big a deal for a LOT of guys flying it.
Re: the high idle hang, many (most?) times, that's due to a lean low speed mixture, or an idle speed setting that's been set a little too close to the "step" (2500rpm+-).
Point being, fly it and see what you think. If the high idle thing is an issue that ends up being a headache, THEN replace the module. Don't replace it just because there's a potential problem. It's not THAT big a deal for a LOT of guys flying it.
Even Xu Liang at RCEXL knew this was a dumb idea,but it's what DLE wanted,I have no idea why.As you say a lot of guys flying them and say they do not have a problem.
I have given away several Ignitions to DL 20 owners just to get them to try the correct timing. Then they realized they had a problem.Anyhow.
BCCHI AMA 2500
03-06-2014, 11:21 PM
#71
Senior Member
Not really the case at all because when flying, even doing 3D, you are well above the RPM where the ignition curve "kicks in". The problem is really just in transition to just above idle or getting the engine to settle back into a good idle. Earlier I gave an example of landing where you are on approach and just about ready to touch down .... but you need just a tiny bit of power to stretch the landing a bit or to aid the flair. That tiny bit of throttle will allow the ignition curve to kick in and you get a burst of power rather than the tiny bit you wanted. Then the dang engine won't settle back to a nice idle for a good touch down. Leads to frustration and some really sloppy landings.
Some people never experience the problem because they never use the throttle, or at least they don't use it in a way that allows the problem to happen. Some others wouldn't know a good running engine from a bad one and likewise they would never experience the problem because they could not identify it.
As others have, with very careful adjustments and a slow enough idle you can sort of work around the problem but it is always there to some degree. It will get you and p*ss you off when you least expect it. The problem can go away completely for under $50 for people that have the older modules.
Some people never experience the problem because they never use the throttle, or at least they don't use it in a way that allows the problem to happen. Some others wouldn't know a good running engine from a bad one and likewise they would never experience the problem because they could not identify it.
As others have, with very careful adjustments and a slow enough idle you can sort of work around the problem but it is always there to some degree. It will get you and p*ss you off when you least expect it. The problem can go away completely for under $50 for people that have the older modules.
BCCHI
03-07-2014, 03:52 AM
#72
I am of a different group and I know my RC plane engines well. Being a certified mechanic over the years and working on many types of engines and mechanical equipment since I was a kid I can detect even different sounds in an engine. I have even told people when an engine was going to fail due to hearing the internal sounds. If you work with engines long enough you can develop this type of skill. I even know when my cars are developing an issue - wife wonders how I do it, yet it is normal to me and nothing new at all. It is just part of my internal mechanisms.
I am like that with PCs, home appliances, heating and ac, and many things really. I am not perfect with it and no, I don't guess them all, but not too bad for a jack leg. Some consider it a great skill, yet at times it can be troublesome and a burden to me. I have been on job sites and told the guys that they are developing issues with a hydraulic cylinder and they would look at me like I was a total idiot. In a few days, they would have the cylinder off repairing it. It is an aptitude I developed from a young boy by running the snot out of engines and building mechanical junk and just having an overall "knack" for that stuff.
I was one of those guys that bought a bicycle and turned it into a wild bike from three different bikes with grandpa's drill press as a starting point. I remember me and my cousin getting a mini-bike as payment one summer for working a crop of tobacco. Well it was not long before my uncle, me, and my cousin had turned his into a three-wheeler. That was before three wheelers became the "big deal" and we rode the wheels off that thing - talk about fun!
With all of this being stated, you can see why timing and the way an engine runs is important to me.
I am like that with PCs, home appliances, heating and ac, and many things really. I am not perfect with it and no, I don't guess them all, but not too bad for a jack leg. Some consider it a great skill, yet at times it can be troublesome and a burden to me. I have been on job sites and told the guys that they are developing issues with a hydraulic cylinder and they would look at me like I was a total idiot. In a few days, they would have the cylinder off repairing it. It is an aptitude I developed from a young boy by running the snot out of engines and building mechanical junk and just having an overall "knack" for that stuff.
I was one of those guys that bought a bicycle and turned it into a wild bike from three different bikes with grandpa's drill press as a starting point. I remember me and my cousin getting a mini-bike as payment one summer for working a crop of tobacco. Well it was not long before my uncle, me, and my cousin had turned his into a three-wheeler. That was before three wheelers became the "big deal" and we rode the wheels off that thing - talk about fun!
With all of this being stated, you can see why timing and the way an engine runs is important to me.
The ignitions from RCEXL and branded as RCEXL are not step down types.
03-21-2014, 01:34 AM
#74
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For those looking for replacement ignitions this one has worked well for me and for the price you can have a spare or two. Comes with an extra hall sensor as well. Comes with the 10mm cm-6 plug cap installed and an extra 14 mm plug loose. They used to come with 2 cm-6 caps but my last ordered had it corrected with the 14mm cap. No idle hang issue either. I've only run 4 cell packs or a diode with life so keep that in mind.
https://www.hobbyking.com/hobbyking/...s_Engines.html
If you don't need the extra hall sensor this one is a few bucks cheaper.
https://www.hobbyking.com/hobbyking/...C_Engines.html
https://www.hobbyking.com/hobbyking/...s_Engines.html
If you don't need the extra hall sensor this one is a few bucks cheaper.
https://www.hobbyking.com/hobbyking/...C_Engines.html
Last edited by Mikecam; 03-21-2014 at 01:38 AM.