I have a couple of the old E-Flite timers that I have been using but I'd like finer control over the flight time and I hate the way it slowly shuts down the motor.
What little I have read about some of the timers on here, they sound like they are do it all units. At this point, I'm just want to start and stop the motor at a set time, although a motor sag for a second or so just as a warning would be nice.
I was also thinking maybe a simple RC system with just an on off switch. I know there are basic transmitter modules that can be adapted but the electronic end of it is beyond my knowledge level at the moment.

Suggestions?

I have a couple of the old E-Flite timers that I have been using but I'd like finer control over the flight time and I hate the way it slowly shuts down the motor.
...

Suggestions?

The eflite timer has no method of controlling RPM other than the initial 'throttle setting' that you program in.  It sounds as if you are setting the run time too long for the batteries to maintain the power setting.  (If you were to set a minimum run-time, would you get a cleaner cut-off?).  At any rate, the simplest, cheapest replacement is the Hubin/Brodak FM-1a - which you program by setting pots with a screwdriver.  If you don't change the pots, the flight will be the same every time.  It does have four adjustments, rather than the 3 that the e-flite has - but the 4th is just an adjustment that adds some RPM at a few intervals to make up for battery voltage sag.  If you just turn that pot all the way down, there will be no power addition.  I would recommend that you just set it at half-way, and forget about it until you wish to play with it.  It also has a motor sag warning that the end of the flight is about 5 seconds away.

The other 3 adjustments - Flight time, Power Level, and 'Delay' should mimic adjustments that are also needed on the e-flite timer.

This timer is available from Brodak or directly from Wil Hubin and costs about $17.  It requires no programmer (other than a small screwdriver) and works with any ESC.

As for the RC system - yes you can do that, and you wouldn't even need a switch - you would just plug the ESC into the Receiver and when you go to low or zero throttle, the motor will stop.  That will cost considerably more than the $20 or so that the Hubin timer costs.

I know I'm not overrunning my batteries on the E-Flite timer. They are coming down with about 35% capacity left.  It just takes about a lap and a half to go from full power to shut off. I'd rather have just enough of a warning to let me know times up and then a quick clean shut down say 5 seconds later.
The "fancier" timers have their place and I'll likely end up with some in the next year or so if I continue to pursue electric stunt competition. But for now, I'm looking for simple. How does the Hubin timer shut off? Is it a gradual slowdown or a clean shutdown like a nitro engine?
The radio idea comes from my idea of solo flying. With power on a switch on my belt, I can fly solo without the need for a stooge or anything else. RC car tx's also have timers that can alert me when to land. I just don't want a big tx hanging from my belt.

There's a number of different Hubin timers, and I'm not familiar with the range of them.  You might want to contact Will directly and ask, or start a thread titled "which timer should I buy"?  With one exception, all of the timers that folks use in serious competition around here just shut the plane off -- if you want to know just when, look at your watch.  Since it takes a set amount of time to fly the pattern you can just program in enough time to finish the pattern with maybe five or ten extra laps in case you want to take the occasional extra lap between maneuvers.  Then go fly, and remember that it'll just -- stop -- when it's done.

There are two serious downsides to the radio idea that I can see: first, without a helicopter-style governor in the ESC it'll still slowly lose power through the flight, unless you play the throttle, and second, unless the rules have changed it's not legal in competition.

  ... I'd rather have just enough of a warning to let me know times up and then a quick clean shut down say 5 seconds later.
The "fancier" timers have their place and I'll likely end up with some in the next year or so if I continue to pursue electric stunt competition. But for now, I'm looking for simple. How does the Hubin timer shut off? Is it a gradual slowdown or a clean shutdown like a nitro engine?

Matt

It gives a warning - slows the motor and speeds it back up twice - 5 seconds before shutoff.  Then 5 seconds later, it shuts off - abruptly.
If you have your ESC set to "Brake", it will shut off very abruptly.

You can contact Wil at:
whubin@kent.edu

I would get the FM-1a and set the 'Advance' function in the center and then leave it alone at first.

I am attaching a couple pages from his information sheets.  (Couldn't fit all four into a single post).