Richard Hayward 6 Posted March 12, 2020 Share Posted March 12, 2020 Hope you guys can help me again. I've recently bought the new VQ Spitfire. From the UK importers (Macgregor) I also bought the recommended motor / ESC combination (720KV, 860w motor and an 80A ESC). Transmitter is Futaba 10J (which I am using quite happily with an Acrowot and Phase 5e). Battery is a fully charged 5s. Prop APC 13x8E. I set up the Tx throttle range as per instructions. Motor powered up OK, but passing around three quarters throttle, it started juddering and rpm tailed off. Amps at this point around 25 - dropped as the stuttering started. Returned both items for refund. New ones exactly the same! Tried changing the timing from Med to Low and High. No significant change. Returned both for a refund and bought another similar combo from different supplier (different badge, but pretty sure same manufacturer). Same result!! So, I'm thinking it can only be a Tx problem? I'm at a loss - any suggestions gratefully received!! Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted March 12, 2020 Share Posted March 12, 2020 What voltage is the battery pack showing when it starts stuttering? Are any of the connectors getting hot? Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks Bob. Out at the mo. Will try when home and also a different battery Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted March 12, 2020 Share Posted March 12, 2020 Don't the car boys call that cogging ? I've had it on two planes ! Both times it was dodgy motor/esc connectors . Took a lot of investigation on bench but eventually plug lead parted ! Saw it on a club mates plane and he got it down and leads parted with just a gentle tug ! You can bring down the top end of the throttle curve as well if testing doesn't show up soldering . Did this by 8% on new bipe till got it on bench. Hope this helps ! Colin Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks Colin. Something else to try when I’m allowed home after shopping! Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 12, 2020 Share Posted March 12, 2020 I have had this problem on one of my planes. It sometimes wouldn't restart after closing the throttle but would just oscillate . Problem on that model was poor quality / connection on the bulit conectors on the motor leads. Another model with similar problem was a broken lead in motor. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks ED. It does seem to be pointing to the motor connections, but does seem odd that same prob on three motors from different sources. Still out shopping, so will continue later....... Quote Link to comment Share on other sites More sharing options...
J D 8 Posted March 12, 2020 Share Posted March 12, 2020 Another who had the same problem and it did turn out to be poor connection on a motor wire. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted March 12, 2020 Share Posted March 12, 2020 Posted by Richard Hayward 6 on 12/03/2020 11:13:26: Thanks ED. It does seem to be pointing to the motor connections, but does seem odd that same prob on three motors from different sources. Still out shopping, so will continue later....... Timing Maybe? For a brushless motor, the number of poles (magnets) determines the optimum timing. Less timing advance is more efficient and higher timing advance is more powerful but uses more juice, within the range that a particular motor can use. Low Timing Advance Timing Degrees – 5 & 10 Motor Poles – 2 to 4 Expected Performance – Good balance of power and efficiency Motor Poles – 6 or more Expected Performance – Best efficiency and run time (lowest power) Standard Timing Advance Timing Degrees – 15 & 20 Motor Poles – 6 to 12 Expected Performance – Good balance of power and efficiency Motor Poles – 14 or more Expected Performance – Best efficiency and run time (lowest power) High Timing Advance Timing Degrees – 25 Motor Poles – 12 Expected Performance – Highest power, less efficiency Motor Poles – 14 or more Expected Performance – Good balance of power and efficiency Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted March 12, 2020 Share Posted March 12, 2020 Just a thought. George at 4-Max always tells me to cut off the soldered ends of the wires and use lead solder to make the joint or solder on the plugs and bullet connectors. Non lead solder is rubbish for home soldering. Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted March 12, 2020 Share Posted March 12, 2020 Several of us in the club had the same problem with the Durafly Vampire. After changing fan units / esc's etc. it turned out to be one of the bullet connectors to the motor. Several fan units had the same fault. It was fine at low to medium rpm, but at high rpm the vibration caused one of the connectors to make and break quickly. Hope that helps. Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted March 12, 2020 Share Posted March 12, 2020 Having re-read OP it seems really strange that 3 combos have same problems ???? I take it the tx works normally on other planes ?? Set up another model memory ?? Colin Quote Link to comment Share on other sites More sharing options...
J D 8 Posted March 12, 2020 Share Posted March 12, 2020 Richard may be on to something with the battery, would a poor connection here result in the same problem? John. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks for all your interest. I’m in the process of charging a different battery. The existing one works fine with a Quantum motor in my Acrowot using the Futaba radio. Will try out all your ideas later today. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Tried a 4s battery - same result. Have changed the timing from Med to Low and High - same result. Connectors don't feel hot, but there is a lot of propwash. Have emailed Steve Webb (who I bought the setup from) to see if has any ideas. Meanwhile, keep coming up with suggestions please! Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted March 12, 2020 Share Posted March 12, 2020 Struggling now !😥😥 Reset throttle end points / curve !! Try different Rx ? One that's ok in different plane !! Colin Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks Colin. Will go and have a play......... Quote Link to comment Share on other sites More sharing options...
extra slim Posted March 12, 2020 Share Posted March 12, 2020 Had this a good few times, from my experience, it is either 1. Timing or 2. Re-solder connectors on both ESC to motor and motor to ESC.. do one at a time if you want to find out which one it was... if these fail, it tends to be wire in the motor windings.. but rare for me. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Thanks Extra Slim. I'm very tempted to solder new connectors on motor and ESC - just want to check that it won't bu@@er the warranty if it doesn't work. Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted March 12, 2020 Share Posted March 12, 2020 Richard. It's highly improbable that 3 combos have the same fault from new especially if pre soldered ! Can you not put a working motor /esc into the mix to prove tx and Rx and lipos are ok ??? Scratching my hair out now !!😀😀😀😀 Colin Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 12, 2020 Author Share Posted March 12, 2020 Good idea Colin. I’ll swap motors from my Acrowot and vice versus tomorrow. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 13, 2020 Author Share Posted March 13, 2020 Right. Have redone all connectors with new items and leaded solder. Have tried a known good receiver from Acrowot. Still the same. Think it must be something in the Tx settings, but really have no idea what as I set the throttle range in the ESC in the usual way. Quote Link to comment Share on other sites More sharing options...
Richard Hayward 6 Posted March 13, 2020 Author Share Posted March 13, 2020 P.S. Just going to remove motor from Acrowot and try that on the new model's settings. Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted March 13, 2020 Share Posted March 13, 2020 Richard. It's starting to look like tx settings ! If the Wot combo results are bad it must be. I'm a Spekkie man myself so can't help there ! Top end set over 100%. ?????? Colin Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted March 13, 2020 Share Posted March 13, 2020 Posted by Richard Hayward 6 on 13/03/2020 15:26:19: Right. Have redone all connectors with new items and leaded solder. Have tried a known good receiver from Acrowot. Still the same. Think it must be something in the Tx settings, but really have no idea what as I set the throttle range in the ESC in the usual way. You have a handle on it now Richard 3 motors throttling exactly the same way as the Tx range was set Go back and check and reset the throttle range as per instructions in the usual way, but not as you did before Edited By Denis Watkins on 13/03/2020 16:33:17 Quote Link to comment Share on other sites More sharing options...
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