Author Topic: RPM adjustment with timer and/or ESC? (Read 2395 times)

Mike Scholtes · « **on:** October 10, 2009, 09:08:51 PM »

In setups using a programmable ESC and also an adjustable timer (e.g. ICE 50 and Hubin timer with fine and gross rpm mini-pots) what is the protocol for setting the flight rpm? My understanding (and this is still at the theory stage for me) is that the RPM can be programmed into the ESC using the USB link and Castle software. But, the Hubin timer also has two RPM pots.

What is the interrelationship of these components in setting and adjusting flight RPM, and how does one set and then field-adjust RPM?

Alan Hahn · « **Reply #1 on:** October 10, 2009, 09:30:52 PM »

Mike,
It all depends. I won't say much about the Hubin timer because I need the manual to sort out the way to set the pots (I need the manual for my JMP-2 and Ztron too!

).

Basically you have two options with the Castle Creation Phoenix line--one is a standard governor mode like I think most other ESC governors available. Here the ESC has a range of rpm that can be set by the timer throttle output.

The other mode is the "Set RPM" mode. Here you program 3 rpm settings into the ESC. Zero timer throttle will give motor "off". Throttle values above zero, but less than 50% will give setting #1, values above 50% but less than 100% will give setting #2, and 100% throttle will give setting #3.

You choose which type of governor rpm mode to use in the CC PC software.

Hope this helps.

bob branch · « **Reply #2 on:** October 11, 2009, 06:46:29 AM »

Mike

I use the Hubin timers in the governor mode, not fixed rpm. In fixed rpm the black selector switch on the red section of the Hubin timers that have the capability is set away from the two adjacent pots. The rpms are set in the castle link program as Alan described in the previous post. . In governor mode the switch on the timer is set towards the two adjacent pots. The the fine rpm adj pot is set in the middle. The course rpm adjustment pot also about in middle and you do an rpm check, using the coarse pot to get to the ballpark range (+ or - 700 rpm or so) of what you want. The fine tune pot is then used to adjust the final rpm setting to exactly what you want on your tach. Ideally you would like the fine adjust pot accesable from outside the plane. At least I find it easier that way. With a profile its not a problem as the timer is usually external. I have seen it mounted by Rick Sawicki on the floor of an open cockpit. That was nice and simple. I have Will add the remote fine tune pot (and start switch for that mater) to my timers. Both are then located on the outside of the fuse. The fine tune pot protrudes like a needle valve and fine tune rpm adjustment is done with the plane on its wheels at the circle if I need to change. No computer or link required. In this mode you operate in the same rpm range thru the flight. But in the castle link software you can adjust the ramp up speed if you want a low power takeoff roll.

bob branch

walterbro · « **Reply #3 on:** October 11, 2009, 08:03:36 AM »

Hi Mike - Bob has described how to adjust your RPM at the field with the plane ready
for takeoff using an adjustable pot. I use the same Gov. mode HIGH setting in my
CC 45 ESC with a Zigras timer V4 series. This timer has a pot that mounts internally
with the pot shaft extending out of the fus. You set the timer to the desired RPM
and then use the pot to adjust the rpm up or down like an electronic needle valve.
These timers are sold by Mike Palko.

Later
Walt Brownell

John Cralley · « **Reply #4 on:** October 11, 2009, 03:03:10 PM »

Mike,

Will Hubin makes several timers with different functions. I have a couple the that Will programmed for me specially for the "set RPM" mode that Castle Creations has for their Phoenix ESCs. I believe he called these FM-2A model (I'm about 300 miles from home and cannot check them right now). Anyway, these timers are programmed to step through the 3 RPMs set by the ESC. One sequence goes through the 1, 2, 3 RPM sequence and the other the reverse (if I recall correctly which I may not!!!). I can select the sequence with one of the pots. I my case he has it so that about 6 seconds before shut down the second RPM occurs for a second or so and then the third RPM runs for the remainder of the flight. This gives a burp that signals the end of the timing period is about to occur.

I guess the bottom line is that Will can program the timer pots to do various things and if you work with him he can set the timer functions to meet your needs. You need to tell him what functions you want. I believe if you wish he could use the pot designated as "stooge" to run two (or more) particular sets of RPMs etc. This might be useful if you have no need for the "stooge" delay that he programs into that pot.

DISCLAIMER: I cannot officially speak for Will so you need to contact him yourself.

Cheers John

Douglas Ames · « **Reply #5 on:** October 11, 2009, 03:42:38 PM »

Is the Governor mode used more for heavy models where the motor is running a higher percent of power?
Would Fixed RPM be a better choice for a lighter model -less wing loading?
I'm thinking the Governor mode was designed for R/C 3D hover maneuvers and the like, but can be used for CL for slightly under-powered models.

Alan Hahn · « **Reply #6 on:** October 11, 2009, 06:09:10 PM »

Doug,

"Set RPM" is a governor mode.

I find it easier to zero in on a rpm and then just fix it. When I use to use the other CC governor mode, whenever I played with my timer, I was never positive if I had the rpm back to where I wanted it.
So I find a rpm that I feel comfortable with for all kinds of weather--and fix it in the ESC.

Dennis Adamisin · « **Reply #7 on:** October 11, 2009, 08:14:55 PM »

I'll second what John & Alan said.

"Setting the needle", using a tach will certainly work, but consider this: an optical tach usually is at the mercy of how well it "sees" the prop, and can easily vary a couple hundred RPM. On the other hand the ESC is a direct self-adjusting input/output tachometer. If I tell it I want 10,000 RPM then that is what it will try its best to achieve!

I use the Set-RPM mode, with the prefered RPM as the middle setting. If for what ever reason I want to run faster or slower, I have the lower RPM set 100 RPM lower than the midpoint, and the higher RPM set 100 RPM faster. Yes, it usually takes a few short test hops to zero in on the correct speed, but it is pretty darned easy to reel it in...

bob branch · « **Reply #8 on:** October 12, 2009, 05:40:19 AM »

I think the nice thing is that Will Hubin has given us the choice to do it either way. They both get you to the same place, its just which one makes the most sense to you and that will be different for each of us. To me the thing I am trying to adjust is lap time. That is the variable I am locking in. Doesn't matter if its measured with an optical tach or one in the esc, its all just a way of gettting to the lap times we want. As Dennis pointed out he like most of us do a test flight or two to get the speed right for the weather condition and then leaves it unless there is a change during the day. Both ways work and work well. Its one of the nice luxuries we have now in electric CL.

bob branch

Will Hubin · « **Reply #9 on:** October 12, 2009, 08:13:20 PM »

If I know that someone is going to use the Phoenix "High RPM" mode, I can set up a single pot to cover about a 2,000 RPM range (say, 9,000 to 11,000), as in the FM-2 and FM-2R, with throttle values between 20% and 50% of full throttle (1.20 ms to 1.50 ms pulse widths). But other modes, such as the "Simple RPM" mode and the "Low RPM" mode have a different calibration, as do the Hacker being sold through RSM and the Schulze F2B. With two RPM pots, as in the FM-2a and FM-6a, it is possible to cover the whole throttle range and so it can be used with any governed RPM mode whatsoever; the idea is to center the "fine" pot and then use the "RPM" pot to get the middle of the RPM range that you want, and use the fine pot thereafter for small changes. In each case, it is possible to make changes in throttle values of about 1/2 of 1%, probably as good as the ESCs can utilize. All of these timers allow the user to adjust and tach the RPM in the first minute of "flight" time. And, in each case, the warning of the end of flight time is made by selecting one second worth of lower RPM.

The "Set RPM" mode of the Phoenix is quite different in its requirements; you get RPM #1 for throttle settings below 50%, RPM #2 for throttle settings above 50% but less than 100%, and RPM #3 for 100% throttle. I can set up a single RPM pot to easily access these three RPMs; for anything close to fully counterclockwise, a single pulse width in the less than 50% throttle range is sent; for anything in the middle of the pot's range, another single pulse width in the 75% range is sent; for anything close to fully clockwise, a full throttle pulse width of 2.00 ms is sent.

A timer with two RPM pots could theoretically access all three RPMs, but the warning RPM would always be RPM #1, thereby making that RPM rather unusable. So I normally set up a single RPM pot timer for either High RPM (or another simple governed mode such as the Schluze) or the Set RPM mode. In the Set RPM mode, the warning is given using RPM #1 if that is not in use and RPM #3 if it is--placing a requirement on the user to select RPMs that differ in 500 RPM or so if the warning is to be noticeable (I tried initially to use a momentary "off" throttle, but that takes far too long to recover.).

The FM-6a is unique in that I used a larger version of the microcontroller and so could incorporate both two RPM pots and a switch to select either the program for an adjustable, governed RPM for any ESC or the program for the "Set RPM" mode of the Phoenix. But since there were two RPM pots and the "Set RPM" mode really only needs one, I added a couple of optional variations for using the three RPMs via the "fine" pot.

Mike Scholtes · « **Reply #10 on:** October 12, 2009, 10:13:38 PM »

Many thanks to all of you; this has been a very helpful discussion. If I understand it right, we are using the helicopter rpm governor modes in the Phoenix ESC; the instructions say the "governor mode low" "determines the RPM the motor will run and the controller will attempt to hold that RPM regardless of how the load changes" [to control rotor head speed]. Sounds like what we want.

Is the sequence to (1) set the ESC rpm via the Castle software, then (2) run the motor in the model and tune the pots in the timer to refine the rpm? In essence, the ESC rpm choice is kind of an educated guess, and the timer is used to set real rpm for flight?

Wil, I have your FM-2a timer with remote start (three actually).

Mike Scholtes · « **Reply #11 on:** October 12, 2009, 11:51:30 PM »

To follow up on my own question, I downloaded the Castle 3.18 software and connected the ICE 50. After a few minutes of "no connection" message I discovered the 3-prong connector will go on the Castle Link either reversed or correctly. That done, the program prompted me to enter motor and battery data, which I did. Incidentally the newest update acknowledges "control line" as a vehicle type, so they know we exist and are not flying helicopters, sort of.

I chose "governor low" mode and set 8000, 9000 and 10,000 as the three rpms for up to 50%, 50-99%, and full throttle. It would not allow me to enter a number higher than 10K rpm, saying the motor and/or battery capacities are wrong. I don't think so, as the TGY 42-50 650kv motor and 5S batteries are used by others on this forum successfully. Anyway, I think I have programmed the ESC to operate in the 8000-10,000 range, which should get me in the ballpark.

So now do I fine tune the rpm with the timer pots? Will the ESC refuse to deliver rpm above 10,000, regardless of the timer rpm settings? I would guess the answer is "yes" but not sure.

Alan Hahn · « **Reply #12 on:** October 13, 2009, 07:45:34 AM »

Mike,
In "low governor mode" the rpm settings have no effect, they are there only for the "Set RPM" governor mode. (At least I think so)

As a comment on the history of the CL mode, I think the only difference between the CL and Helicopter modes, is that CL governor allows you to enable the prop brake. This was (and still is) strictly forbidden on the Helicopter governor settings--basically it would be a disaster for a chopper to have its rotor blades stopped simply because you might go to zero throttle (like in a auto-rotation). I think it was Den Pappas who helped convince CC to give us a "brake" (pun intended), which they finally did in the summer of 2008.

But other than that there is no difference between CL and Heli governors. So whatever is being done for (or to!) the heli governor in the software/firmware updates is likely to affect us too.

Anyway those warnings you are getting are probably aimed at helicopter setups---yes they may be ok for us because our power changes (about 30% between cruising and maneuvering) still allow an "ok" overhead in available power. But for helicopter, the 10k rpm setting may not have sufficient headroom to give enough power to get out of trouble.

And no, the ESC will give you whatever you try to give it, as long as the rpm is within the low governor band--this also depends on your motor and how many magnets it has in it. I don't recall what the allowed range is.

I may be wrong about this, I really haven't played with the low and high governor modes for the last year or more.

Will Hubin · « **Reply #13 on:** October 13, 2009, 10:29:36 AM »

The "Low RPM" mode goes from about 1650 RPM (1.20 ms or 20%) to about 9200 RPM (1.90 ms or essentially full throttle). So if you want more than 9,000 RPM, use the "High RPM" mode (8,000 RPM at 1.20 ms to 11,760 RPM at 1.50 ms, in my test, and it will go higher).

Larry Wong · « **Reply #14 on:** October 13, 2009, 03:51:13 PM »

Will:
Can I use your FM2a timer with a Schulze F2b or do I need a BEC,?

Alan Hahn · « **Reply #15 on:** October 13, 2009, 05:36:22 PM »

Quote from: Larry Wong on October 13, 2009, 03:51:13 PM

Will:
Can I use your FM2a timer with a Schulze F2b or do I need a BEC,?

Doesn't the Schulze have a BEC?

If not, I always thought that it should be possible to use the balancing plug to grab the first cell off the pack to supply 3.5V. It would be a negligible drain of the battery. Only issue( AFAIK) is whether it is enough voltage or not.

Of course Will is the expert here.

Larry Wong · « **Reply #16 on:** October 13, 2009, 06:14:49 PM »

Well Alan
I think I just have to many things to choose from, I like Will Hubin's it what I call "KISS" But I also have FMA timer and Z-Tron with Pot and switch , and C/C -45 and C/C -60, Schulze F2b ESC ,Jeti ESC. for AXI motors Hacker XL, Plettenberg 30-12 Humm I think I 'm Hooked, my wife keeps saying remember it's only a hobby!

Will Hubin · « **Reply #17 on:** October 13, 2009, 07:29:26 PM »

The Schulze does not supply a BEC. I haven't tried using one of the cells; the voltage is plenty for the microcontroller I use but I'm not sure if the ESC would consider the output voltages high enough to be unambiguously interpreted as logic 1s.

I did buy a Schulze and calibrated its RPM range (it is a little more spread out than the High RPM of the Phoenix, so potentially the resolution could be a little better, say 40 RPM versus 50 RPMS). I matched it with one of my FM-2R models, which includes a 5-volt regulator to power the timer. The regulator's input leads have to be attached to the battery leads of the ESC; it is easy to do, just use a wire stripper to open up a gap at a convenient place and solder, or connect well, the leads. I delivered combination to a customer and he's reported no problems. The regulator probably presents a cleaner 5 volt signal than a normal BEC.

I've been flying two airplanes for many flights with the FM-2R, with the regulator supplying the 5 volts for the timer. No problems. There is no reason to have to pay for the extra weight and cost of a separate BEC!

Larry Wong · « **Reply #18 on:** October 13, 2009, 07:47:26 PM »

Will:
What do you use for a 5v supply? ( Battery)

Alan Hahn · « **Reply #19 on:** October 13, 2009, 08:14:43 PM »

Quote from: Will Hubin on October 13, 2009, 07:29:26 PM

The Schulze does not supply a BEC. I haven't tried using one of the cells; the voltage is plenty for the microcontroller I use but I'm not sure if the ESC would consider the output voltages high enough to be unambiguously interpreted as logic 1s.

I did buy a Schulze and calibrated its RPM range (it is a little more spread out than the High RPM of the Phoenix, so potentially the resolution could be a little better, say 40 RPM versus 50 RPMS). I matched it with one of my FM-2R models, which includes a 5-volt regulator to power the timer. The regulator's input leads have to be attached to the battery leads of the ESC; it is easy to do, just use a wire stripper to open up a gap at a convenient place and solder, or connect well, the leads. I delivered combination to a customer and he's reported no problems. The regulator probably presents a cleaner 5 volt signal than a normal BEC.

I've been flying two airplanes for many flights with the FM-2R, with the regulator supplying the 5 volts for the timer. No problems. There is no reason to have to pay for the extra weight and cost of a separate BEC!

I suppose you could plug into the first 2 cells then--The main advantage to that would be that it would be a plug-in connection as opposed to a solder. A disadvantage would be you would have to plug it in every time the battery was used. But since I don't have a Schulze, I really don't have a dog in this hunt!

Will Hubin · « **Reply #20 on:** October 14, 2009, 02:52:24 PM »

Larry,
The regulator is designed to take a higher DC voltage and bring it down to 5.0 volts. The "regulator" part means that it has to maintain a constant voltage output independent of the current draw. It is a "linear" regulator and it must dissipate as heat the current it supplies times its internal voltage drop--but this isn't a problem for our timers because they draw so little current. The regulator I use on the FM-2R and FM-4R is a 78L05, which is able to handle up to a 5S LiPo battery pack, connected directly across the battery leads of the ESC. The regulator I use on the FM-6R is a 7805, which is able to handle up to a 6S LiPo battery pack. In each case the regulator is on the circuit board and leads are provided to connect to the ESC's battery leads. Connecting the timer to the ESC isn't a problem because they'll be used together indefinitely.

Dean Pappas · « **Reply #21 on:** October 14, 2009, 08:52:08 PM »

Larry,
Castle and other companies make high voltage BECs which will work nicely, even if overkill and a tiny bit heavy. Will's suggestion of using a 7805 regulator is a good one, and the parts are available from Radio-Shack.
Now I have to go draw a schematic and write out a parts list!
Dean P.

Author Topic: RPM adjustment with timer and/or ESC? (Read 2395 times)

Alan Hahn

Alan Hahn

Alan Hahn

Alan Hahn

Alan Hahn