Motor stutters near full throttle

[Richard Hayward 6]

Thanks Dennis - I don't know any other way to set the range other than:

Turn Tx on, Throttle to max, turn Rx on, wait for beeps, throttle to min. ????

[Denis Watkins]

Ahh But, the sticks may not be calibrated well

Or there may be some latent end point setting or sub trim left in

Basically, your Throttle stick may be going too far down and not enough up.

 

If you have a Servo Monitor on your Tx, with the Rx switched off, move the Stick fully up and down

And watch the cursor move steadily fully left and fully right.

Go into sub trim and dial out any trim to zero

Check there is zero expo

Check end points are not over 100% and for now set those 95%

While you have been testing recently, you didn't mention if the model was tethered, And with prop on or off

But usually from now, proceed with the prop off as the next step may involve the prop bursting into life.

 

Edited By Denis Watkins on 13/03/2020 17:02:36

[Trevor]

Surely the easiest way to check whether the problem is in the Tx (or Rx) is to drive the ESC from a servo tester instead. If the motor throttles smoothly with the tester, it’s a radio problem. If the problem’s still there, my bet would be excess current causing the ESC to complain. Although I have to agree that when I’ve seen this behaviour in the past, it’s usually been down to motor/ESC wiring defects.

Trevor

[Richard Hayward 6]

Thanks Dennis. No servo monitor on Tx. SubTrim 0. Expo 0. Tried trims at 95%. Still the same problem. The problem only shows with the prop on.

Trevor. Ii don't have a servo tester (yet!). I can't see excess current being a problem as it only gets to around 25 Amps when the motor cuts

[Colin Carpenter]

Richard. How about trying on 3s lipo ,smaller prop ? Straw clutching now ! Colin

[J D 8]

My T8j has a servo monitor, if by that Denis means the servo test screen in the power down mode.

John.

[Richard Hayward 6]

Dennis. I'm relatively new to electric flight, but I thought the whole point of calibrating the throttle movement with the ESC was to take account of all the differencies in different transmitters?

[Tony Richardson]

With some transmitters and esc combinations the TX throttle trim must be all the way down before calibrating, have you tried this ????

[Dickw]

Posted by Richard Hayward 6 on 13/03/2020 16:39:31:

Thanks Dennis - I don't know any other way to set the range other than:

Turn Tx on, Throttle to max, turn Rx on, wait for beeps, throttle to min. ????

Not sure if this is what you meant, but my version would be:-

Start with Lipo disconnected - (but Rx turned on if you have a separate switch?)

Turn on Tx, throttle to max, connect Lipo to ESC, wait for beeps, throttle to min.

Dick

[Former Member]

[This posting has been removed]

[Richard Hayward 6]

The wires are stock. As mentioned, all joints have been resoldered. The combo should cope with an 8s pack. I am using a 5s and have tried a 4s with same result! Amos peak at 25, so we’ll under what should be the limit

[Richard Hayward 6]

Sorry. Amps peak at 25 so well under ....,

[Peter Christy]

Just a thought, as I'm not that familiar with Futaba systems. Have you got high frame rate enabled?

Standard frame rate is around 18mS (give or take) but many 2.4 GHz sets allow a higher frame rate (9mS or so) in order to reduce latency. Usually its only servos that object to high frame rate (should only be used with "digital" servos), ESCs are usually tolerant. But if you have selected high frame rate, it might be worth trying it at the normal frame rate.

You never know....

--

Pete

[Richard Hayward 6]

Thanks Pete. As far as I can see in the manual, there is no option to change frame rate. I’m finding this really frustrating as all my other motor/ESC combos have worked ‘out of the box’

[Denis Watkins]

Richard, have gone back to page 1 of your gear, so I will quote that others may help

These are notes from Mcgregor

Aimed at none-hall, direct current brushless motors, several parameters can be set through a programming card or key on the ESC and are convenient to use.

• Easily configured using a programming card.
• System can automatically detect throttle neutral point.
• 3 timing modes can match different motors.
• 3 modes of start force adjustment.
• Governor mode for heli
• Reverse motor direction

Lads, a question

Does Governor mode prevent overspeed?

 

Edited By Denis Watkins on 14/03/2020 15:45:02

[Colin Carpenter]

Richard ! I’ve an idea ! Give up !!😂😂😂 Are you able to take this combo t to a fellow modeller using a different radio system and try to set up anew ! Colin

[Richard Hayward 6]

I think that's a great idea (give up, that is)! No one really local I could use. I think there must just be an incompatibility with futaba! Looks like the seller will refund and provide a different make to try.

[Denis Watkins]

Posted by Denis Watkins on 14/03/2020 15:42:38:

Richard, have gone back to page 1 of your gear, so I will quote that others may help

These are notes from Mcgregor

Aimed at none-hall, direct current brushless motors, several parameters can be set through a programming card or key on the ESC and are convenient to use.

• Easily configured using a programming card.
• System can automatically detect throttle neutral point.
• 3 timing modes can match different motors.
• 3 modes of start force adjustment.
• Governor mode for heli
• Reverse motor direction

Lads, a question

Does Governor mode prevent overspeed?

Edited By Denis Watkins on 14/03/2020 15:45:02

[Richard Hayward 6]

Now getting really interesting. I took a Quantum 55 motor off the Acrowot and plugged it in to the 'new' ESC with same size prop. That runs up to full power pulling 45 Amps without any problems. So, it is beginning to look as though 3 motors all have the same weakness - doesn't it?!!

[Colin Carpenter]

Richard. That’s really interesting ! That would seem to indicate a motor problem I agree ! What brands have given the problem ! Would the Quantum power your new model ? Colin

[Peter Beeney]

Richard,

Does a clue now lie in the fact you have 1350 watts versus 860 watts? It did strike me in the beginning that 25 amps at three quarter throttle on the 13 x 8 prop seemed a bit unusual. Plus the fact that the prop seemed to be the only common link during all your trials and tribulations. I always clock the prop speed with a tacho first anyway, that’s a fairly sure way of seeing what’s going on; for me anyway. And my idle thoughts about a warbird of around 9lbs in weight would be that it would surely appreciate at least 1200 watts of power (or just a little bit more, perhaos...) to fly in that nicely spirited manner that warbird should be flown. Flat out! But that’s only my idea, every one has his own personal choices and ideas. Agreeing with Colin it certainly sounds like the Quantum is a potential contender as a replacement. How would you consider your Spit compares physically with your Acrowot? If more or less the same then a likewise power plant might not be far of the button… I’d have thought that the flying characteristics are perhaps not that much too dissimilar, either…

Good luck with what ever you try.

PB

Edited By Peter Beeney on 14/03/2020 19:58:17

Edited By Peter Beeney on 14/03/2020 19:59:16

[Richard Hayward 6]

Thanks Peter. The spit has much the same span as an Acro, but about 2lbs heavier. Wing section not too dissimilar. Waiting to hear back from the supplier re alternative motors, but the Quantum defo a contender. Colin - the first two motors were included with the Macgregor Boost 50 pack. The latest one is an Overlander Thumper. But, they have identical specs and look identical, so I suspect they are badged versions of the same motor .

[Colin Carpenter]

Richard ! Yes a lot of motors are the same . Badge engineering as you say. I have the Quantum in my Wots Wot. Good verticals ! I have an E Max on 5 cells in an Axiome bipe. From Robot birds - can't remember the number but it's larger than the Quantum. Good luck ! Colin

[David Hall 9]

Following this thread with interest.

I recently bought a set of four 20A ESCs. when tried, the first had an odd "misfire" at anything over half throttle, but only on load. Off load it sounded fine. After a little messing around, I found that all four ESCs had this "feature". I did wonder if I had bought seconds, sold as perfect.

[Colin Carpenter]

Richard. E Max GT 4020/07 in Axiome. Super motor. Colin