Parkzone Spitfire - Crashes Resolved??

[bdg]

Anyone at the field over the past two days might have noticed that my Spitfire crashed both days.... no control at all. On Saturday, problems started and I saw the retracts raising / lowering without command and the subsequent crash to the field due to a lack of control and power; today there was another crash after raising the retracts after take-off. The first sortie today was fine BUT the second was definitely problematic.....

I had been using a stock E-Flite 30A ESC with a size-15 E-Flite motor.

I've been able to replicate the issue and all seems to be okay when the retracts are not binding on lifting. HOWEVER, if there is any binding at all (say due to the landing gear getting pulled back from the last landing), then the retracts draw close to 2A for probably 5 seconds before switching off. The E-Flite ESC is supposed to be able to provide 3.5A continuous (http://www.horizonhobby.com/products/30 ... -EFLA1030B) BUT the voltage browns-out at 2A to 3.5V or so. This is enough to lose the electronics and was enough to shake me. Today, I tried re-applying throttle but w/o any success leading to the crash.

Interestingly, a Turnigy Plush 30A ESC is able to drive this without an issue.

Videos below only capture the retracts in operation... no ailerons, elevator or rudder.

First, normal operation of the retracts with the E-Flite ESC: http://youtu.be/eRNqTlZN7Oo

Next, bound operation of one of the retracts with the E-Flite ESC: http://youtu.be/M8-thqDy1Rc

Finally, Turnigy Plush 30A with retract operation: http://youtu.be/PrQAjJJZ2kw

Just a warning to us all for the future!

Brian

[AndrewS]

Brian,
Glad to hear you have an explanation. I have heard several times that the eflite ESC's are not the greatest...overrated for amps. A 30 amp is more like a 20-25 amp one. Haven't heard any reports about the bec part.

Andrew

[bdg]

Andrew,

At least there is a working explanation. I never tried restarting the ESC on Saturday after I had lost control and tried only to glide it in; I definitely did today.... I should have had enough time to recover after the retracts timed-out but I had no power available from the motor.

While the E-Flite is rated 3.5A, the Turnigy Plush is only rated 2 Amps but was able to handle the load. I had thought that the E-Flite would have been superior to the Turnigy - but I sure was wrong on that one!

I had recently replaced an Orange Rx with a genuine 7-channel Spektrum with satellite thinking that previous issues were a result of that component, as this has been going on for a few flights now.

Hopefully the next flights will be better

Brian

[RocketManRC]

A couple of years ago after a few problems like that I started using the Castle BEC and disabling internal BECs on anything with more than 3 servos. I haven't had any problems since.

Rick

[Rob]

The ESC in my parkzone Trojan failed after the first flight, luckily on the ground just before the second flight. They sent a replacement and it lasted about a year before failing as well so I would agree that the plush is probably the better ESC as I've many of them and to date none have caused a problem or failed.

[CF Av8or]

I agree about the Plush ESCs. I have been using these almost exclusively for the past nearly 10 years and have not had one fail on me.

Vic

[bdg]

So... the plot thickens..... Although the Spitfire was purchased as a PNP, and the replacement ESC is an E-Flite 30A V2 unit, the ESC actually in the plane is a V1.

http://www.e-fliterc.com/Products/Defau ... D=EFLA1030

The point here is that this is NOT rated for 3.5A but only 0.7A continuous from the BEC. Any stuck retract - as demonstrated - will surpass this 0.7A maximum value.

For now, I will be validating that the retracts are operating properly on the ground prior to launch and will probably either not use them in flight or add a separate external BEC (as suggested - thanks!). The Plush is in the plane and ready for the next trial while the E-Flite will become a spare for the moment. This now is my error in surpassing the rating of the ESC....

Brian

[retiredVTT]

I've not noticed this 700 ma rating before......seems extremely low compared to other ESC's
On one hand they say it can handle 5 analogue servos, on the other hand they give it a low current rating.

The Plush esc's have a 5vt/3amp BEC rating on the larger sizes. They also claim they are "Bulletproof"...!

http://www.hobbyking.com/hobbyking/stor ... oller.html

Bill

[waxman]

Thank you so much for posting this Brian. I did notice that you were having issues on Sunday. I was so close to flying my the exact same plane this weekend. Glad I didn't. We have plenty of 30A plush ESCs so I might as well swap it out before hand just to be on the safe side.

Thanks again,

John

[david3484]

Yes this is all great information.

Thanks to everyone for sharing.


Dave M