Hi All,
I have had a three flights with a KR Timer and I like it. Everything seems to be working as it should. One thing that I am not sure on though is that it ramps up to full revs at the start. So I thought I would check this here. I fly from a rough grass field and tend to get the plane up as soon as possible otherwise I can see that the ramp up could be great for contest style smooth take offs.
How long should this ramp up take? Mine takes 2-3 seconds.
Do you wait for the ramp up and then get helper to release/release from the stooge?
I have found posts about slow start up but the ZTW Beetles ESC I am using is set at acceleration NORMAL and so it should be good and I do not have any other problems with the motor run?

If you fly off of rough grass be aware that the prop strike protection in the KR timer does not kick-in until the motor reaches the governed RPM.  On a  grass circle it would be best to wait until the ramp-up is complete before releasing the airplane.

I'd suggest setting the ESC acceleration to HARD and let the timer do what it's designed to do.

Thanks all for your replies.

John- I have read your excellent report before and returned to it before posting here. You wrote 'After the one-minute delay the motor starts running.  It ramps up to full RPMs and then drops back to the set RPMs.' This is what happens with mine but I was just wondering how long the ramp up to full RPM should take? I just want to check that mine is set up to work like it should.
Circuit Flyer - Interesting that you suggest the 'Hard' setting. I guess this is the equivalent of soft start off?
I found a thread where Keith Renecle's ZTW ESC suggests the settings below:
 1- brake hard #4
2 - Lipoly #2
3- cut off 2.8v #1
4- auto motor timing #1
5- sbec 5v #1
6- rpm off #1
7- rotation forward if regular prop #1 if reverse pitch prop reverse #2
8- start up strength 50% #9
9-  low voltage cut off reduce power #1
No: 8 gives the start up strength as 50%

This is for the ZTW Mantis ESC but I have a ZTW Beatles ESC and the only option I have for the start up strength is normal/soft. The default is Normal and so I left it at that.

The Beatles ESC instruction manual available online shows 3 settings for 'acceleration'.  Maybe yours is different. 

I've used the KR timer on several different ESC's.  I always set them for the fastest start-up acceleration.  Similar to you I always see 2-3 seconds to ramp up to the governed RPM, so I guess that's what Keith has built into the timer.

Hi Circuit flyer,
Thanks for letting me know that you also see the same ramp up time; it confirms that all is probably as should be.
The Beatles esc I am using is a G2 version.
https://d3if9wubzr0anm.cloudfront.net/manuals/ZTW3050211-1.pdf

 

2 - Lipoly #2
3- cut off 2.8v #1

Curious about #2,3.  It implies you are set for Lipo batteries.  The low voltage cutoff you are using is the one we use for Li-Ion.  Lipo is normally 3.2.  You probably would not notice it in flight unless something caused you to have an unusually high drain.  I don't use the KR so that may where Kieth wants it set but please check it out.  2.8 is too low for a Lipo.

Ken

2-3 seconds to run up is normal in my experiences. Your hear it overshoot and come back to the governed RPM setting.

Do not launch the model until it’s settled into the it’s governed RPM. If you do and you happen to have a nose over the auto shut down will not work and you’ll burn up your system. I’ve seen a mode catch fire from this scenario.

Always good to take a second, take a deep breath and focus before launching the model.

Thanks for letting me know. I think I will ensure I use a stooge or helper for launches and wait for the spool up.