Stevens Aeromodel Control Line Timer

Additional Details

A control line timer, so simple, you can actually program it at the field!

Control line flying has always been about you, the handle, and the lines. Stevens Aeromodel pioneered electric control line flying back when others thought it couldn’t be done. Unlike the fuel-powered models of years past, an electric model relies on a motor controller, the Electronic Speed Control (ESC), to govern power to the motor. The ESC comes from the radio control side of the hobby. It’s designed to take signals from a transmitter and receiver and turn them into motor output. Flying that way works, but it adds cost, a radio to bind and charge, and a second person flying your model. It also changes the classic control line experience in ways most of us didn’t come out to the circle for. A timer takes the radio’s place. Throttle and flight duration are set on the ground, and the timer runs the motor from takeoff to a dead-stick landing, for an experience similar to the fuel-tank-and-glow days. The timer is the purist’s choice, and it’s ours.

Enter the Stevens Aeromodel Control Line Timer. Earlier timers piled on features and buried them in programming sequences that were hard to get right with cold fingers and a pilot waiting at the handle; ours does the job with one button and one trimmer. At your command, the timer supplies the instructions for motor run-up, manages the flight time, warns that it is time to land, and manages the landing sequence. You simply program your desired maximum motor output and flight time on the ground, and the timer instructs the motor with exactly what you programmed, right down to faking the brap… brap! of running low on fuel. The experience is better than you remember as a child: no more charging glow plugs, no more flipping propellers, no more cleaning oil from models. A clean and predictable electric flight experience.

How a flight goes. Your assistant holds the button and counts. Each LED blink, paired with a short motor blip, adds one minute. When you’ve counted the number you want, release the button. That starts a 5-second delay so your assistant can clear the prop. The motor then ramps up smoothly over 5 seconds and holds steady at your trimmer setting for the time you programmed. Forty seconds before the end, the stumble tells you to set up your landing. The power then fades over 25 seconds to a dead-stick finish. The motor always runs for your programmed time plus 30 seconds, so a 3-minute program gives you 3:30 of motor every time.

No surprises. The timer always powers up with the motor commanded off, so your ESC arms normally and nothing spins until you’ve programmed a flight. A single press of the button at any point in the flight stops the motor immediately and clears the time. Reverse polarity is blocked harmlessly. A solid LED means a programmed run is underway, and flashing means lead-in, lead-out or an interruption, so you can read the timer’s state from the pilot’s handle.

Specifications

Weight	2.1 g
Board size	15 × 35 mm
Flight time	1–10 minutes, set in 1-minute steps
Total motor run	Programmed time + 30 s (5 s ramp up, 25 s wind-down)
Start delay	5 s after the button is released
Landing warning	Motor stumble, 40 s before the end of the run
Throttle range	50–100%, set by the onboard trimmer
Power	From the ESC’s BEC, 5 V only
Connection	Standard 3-pin servo header (GND / +5 V / Signal)
Protection	Reverse polarity blocked, motor off at power-up, one-press emergency stop

Flight Sequence

Phase	Length	LED	What’s happening
Start delay	5 s	Fast flash	Motor off. Assistant clears the prop.
Ramp up	5 s	Slow flash	Throttle rises smoothly to your trimmer setting.
Programmed run	Your time	Solid	Full power at the trimmer setting.
Warning	2 s	Flicker	Engine “stumble.” 40 seconds of power left.
Wind-down	25 s	Slow flash	Power fades gradually. Set up your landing.
Stopped	—	Double-blink	Motor off, time cleared, ready to reprogram.

ESC Compatibility (Important)

This timer is for ESCs with a 5 V BEC only. A 6 V BEC will damage it. Check your ESC’s specification before you connect it. Our SA Sport ESCs all supply 5 V and are a natural match:

Model class	Recommended ESC
1/2A-size electric control line (RingRat 100, FlatRat, SCRAM!)	SA Sport 12A Brushless ESC (JST)
Larger sport models (RingRat 250 class)	SA Sport 20A Brushless ESC or SA Sport 30A Brushless ESC

What’s Included

Timer and printed instructions. Download available here.

Pairs With

Would you like a model to put it in? The timer drops straight into our RingRat 100, RingRat 250, FlatRat and SCRAM! electric control line kits. Add a Vintage 1/2A Control Line Handle Bundle and a set of control lines and you’re ready for the circle.

Frequently Asked Questions

Will it work with my ESC?
If your ESC’s BEC supplies 5 V, almost certainly. The timer uses a wide throttle range that most ESCs accept without any setup. If yours won’t arm, or the top of the trimmer’s travel does nothing, the manual walks you through a quick one-time ESC calibration.

Can I set a flight shorter than one minute?
No. Flight time is 1 to 10 minutes in 1-minute steps, plus the fixed 30 seconds of ramp up and wind-down. If you’re coming back to the circle after some time away, start at 1 minute and work up to 3-minute flights and longer.

How do I set the motor power?
With the propeller removed, turn the trimmer with a small flat screwdriver. Clockwise gives more power, across a range of 50% to 100%. Set it on the ground before you program the time, and treat it as a pre-flight setting.