About time.. ing

[tiqueman]

So just as I started to think I knew what was going on... BAM... another turn in the road.

Feigao motors, specifically 540 XLs. On thier website and in many other areas Ive read that timing should be set as low as possible. 0-ish dgrees. I just read the post about a 9Xl smoking and saw that it was recommended to run higher. I then found another post that states for sport running, run up to 15 degrees.

So 0 degrees is going to cause more heat? And does higher timing mean faster runs?

Class is in session and Im listening!

[sailr]

higher timing than recommended = performance gain but also higher heat. Lots of power lost (wasted) to heat.

General Rule is 2 pole motors like the Feigao use low timing. 0-6 degrees.
4-6 pole motors, SV27, UL1 use medium timing, 8-12 degrees.
More poles, most outrunners, higher timing 12-8 degrees

[BakedMopar]

I know I'm going to cause an up roar but here goes. Too little timming can cause poor performance and heat also. At 3 degrees timming my 540 8xl was comming in at 135. At 7 degrees 130 and 11 degrees 137. At 15 it was the same as 11. These were tested more than once and temps are an average. These were all on a Ice 100 in a OM29 with a m445.

[Fluid]

George is 100% correct, too little timing causes poor performance and excess heat. There is no "general rule" for timing advance, it depends entirely on the motor design and the amp load on the motor. I don't know where this idea of "0" timing advance came from, but it is very ill-advised for 2-pole motors.

The reason for timing advance is to allow enough time for the next coil to energize and build a magnetic field to attract the next advancing magnet. The more wire in the coil or the more amperage drawn, the more advance is required because it takes time to charge the coil. If there is too little timing advance, the coil will energize too late, hurting efficiency and building heat. Bottom line - too little or too much are both bad. You need to experiment to find the optimum for your setup....

I always ran my own turn 2-pole motors with between 10 and 15 degrees advance for oval racing applications where amp draw was 60-100 amps, and up to 25 degrees for SAW attempts drawing over 200 amps. I run 13-17 degrees with my 4-pole Neu "Y" winds pulling 140 amps, and 4 degrees with the "D" winds pulling 160 amps. My Scorpion 8-pole motor likes 15 degrees pulling 80 amps. Clearly there is no hard and fast rule for all motors.

About all I can say with certainty is that "0" degrees is almost always wrong.



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[tiqueman]

Awesome guys. Thanks for the replies. Guess I will be doing some serious reprogramming in the next few days as well as a lot of testing. So chances are, each boat/ set up may req. a different setting depending on what its pulling, even if for example the motors and ESCs are all the same...

Ive been struggling to get the 70 mark on my twin HOTR. 69.8 has been my best w/ 10XLs coming in at about 125-130. Thats also been on 0 degrees. Hmmmmmmm??????? Can you guess what boat I will be tuning first?

[sailr]

Interesting info. My 'general rule' comes from a VERY experienced and FAST FE racer.
Bottom line, there is no real answer I guess.

[sailr]

Let us know if you get better speed and no more heat by increasing the timing. VERY INTERESTING!

Awesome guys. Thanks for the replies. Guess I will be doing some serious reprogramming in the next few days as well as a lot of testing. So chances are, each boat/ set up may req. a different setting depending on what its pulling, even if for example the motors and ESCs are all the same...

Ive been struggling to get the 70 mark on my twin HOTR. 69.8 has been my best w/ 10XLs coming in at about 125-130. Thats also been on 0 degrees. Hmmmmmmm??????? Can you guess what boat I will be tuning first?

[CornelP]

With a very good cooling system, my 10L has actually got an extra 10kph, on the same config and prop. The difference is visible, a new motor. Initially ran on 0, now on 11 degrees. I tried higher, but the trade off is too big... the motor was sizzling when I brought it in after 2min. I have no temp gauge, but the difference was like hand warm with "Aaaargh" (not Ouch!!).
On the Turnigy Aquastar 120, timing is medium. On the others, with selectable values, it is 11 or in the area.

[sailr]

Your experience totally bears out what I said.... 0 timing for Feigaos (2 pole). Higher timing causes more performance but extremely high heat.

With a very good cooling system, my 10L has actually got an extra 10kph, on the same config and prop. The difference is visible, a new motor. Initially ran on 0, now on 11 degrees. I tried higher, but the trade off is too big... the motor was sizzling when I brought it in after 2min. I have no temp gauge, but the difference was like hand warm with "Aaaargh" (not Ouch!!).
On the Turnigy Aquastar 120, timing is medium. On the others, with selectable values, it is 11 or in the area.

[CornelP]

Correct Sailr, on a timed race, with my 9S, timing is zero to get the 6 minutes required. On the bigger boats, I would say it is safe to push at 10-11 if you have cooling. I have read previous threads about this and the two opinions (yours and Fluid) were strangely apart... well you're both right. The ideal would be to run at zero, you do not need the water jacket (I run a 14S on my mono1 500mm) and a pack will last longer. On a race, like we had our drag race, you can push it a bit, but with the necessary precautions. I started doing things a bit different now: see where I am with the speed required by playing with timimg: if the timing is high, just get a bigger kv... working for now :)

[tiqueman]

Interesting info. My 'general rule' comes from a VERY experienced and FAST FE racer.
Bottom line, there is no real answer I guess.

Let us know if you get better speed and no more heat by increasing the timing. VERY INTERESTING!

My set up info came straight from Fiegao! I will post my findings as they happen.

[m4a1usr]

Interesting info. My 'general rule' comes from a VERY experienced and FAST FE racer.
Bottom line, there is no real answer I guess.

There are some answers by some very reputable sources too. Take a gander at what Castle says about motor timing. http://www.castlecreations.com/suppo...ing_guide.html

And theres what Ken has compiled from his own empirical testing. VERY INTERESTING stuff if you read it all. http://homepage.mac.com/kmyersefo/timing/timing.htm

I feel like you do Sailr. But I'm no expert.

John

[JohnZ]

Wouldn't it be great if we could adjust the timing on the fly? If the ESC's were designed to have adjustable timing from the radio? With gas powered RC planes, it can be used to adjust the fuel mixture while flying. I believe this is also done with some glow powered boats.

[Fluid]

I My 'general rule' comes from a VERY experienced and FAST FE racer.

Oh really?
"See, the controller switches the magnetic fields in the motor, so the rotor will turn and follow the electric field. Because of inductance of the coils, this switching needs to be done with some advance to have the full magnetic field in place at the best possible position.

This "timing advance" can be set in some steps. The higher the inductance the more advance is needed, but it also depends on the current (load) and rpm. It also depend on the position detection method and the general construction of the motor....

Most of the common controllers use some kind of (almost) fixed timing advance. It's optimized for the best possible current, the operating point of that motor type. So the timing advance is too much for running the motor without load, this shows in quite to high idle currents. Two pole motors without slots (LMT, Hacker, Feigao) react more on wrong timing than higher pole, slotted motors (Neu, Plettenberg, Outrunners). Thus the idle currents you "see" when you test the motors do not represent the truth. Truth in a way, how high the losses are under the correct load. What you measure is higher, it just hurts the motor and the controller (heat). Misfire may also happen and leads to pretty high voltage spikes which can kill the FET's - which most likely happened to your controllers." Joerg

My "very experienced racer" is faster than yours.......
.

[tiqueman]

Interesting reads. I didnt get any water time yesterday as I hoped. Hopefully in the next few days I can get some testing in and see what reality on my setup is compared to whats recommended.... which is everything from 0 - 30