This is the 2024 “Mk4” “E-FUSE” model of tiny single function DT timer designed by Liav Hershkoviz and Bernard Guest for free flight model airplanes. See the product video here. This new model is a total departure from the previous versions. Half the weight and size and programmable with an android phone via an app that uses the flashlight to “flash” the new program to the timer (you can program it without a phone as well …see video).

Note that a fuse is 0.3g, a viscous timer with spring is 0.8g and with a mousetrap mechanism is 1.5g or heavier. The new tiny timer is only 1-1.25g depending on how it is rigged. It is now competitive with the traditional fuse DT in terms of weight and is far safer and infinitely more precise.

I supply this timer in 3 layouts:

1. Standard Layout - timer with a 3D printed mount with battery wired to the timer ($35)

2. Light - timer wired to battery but no 3D printed mount (saves you half a gram but you need to figure how to mount it ($30)

3. Ultra light - Timer and battery connected and epoxied to make a single 1g unit - install the timer into you DT line to eliminate the need for mounting a timer with springs and mousetrap etc etc. see video here could not be easier and works on any size model down to a 12” catapult glider or P-nut. ($40 because it takes more time to build this version).

The charger for this timer is $10 and simply plugs into the two tiny holes in the timer board with a friction fit to charge the battery. If you opt for the slightly heavier 40 mAh battery you could probably fly for the whole season on one charge (although to be safe I would charge it halfway through the season before a major contest or once every few weeks).

INSTRUCTIONS

Notes on using the e-fuse

First, if you are struggling to get it to respond moisten your finger slightly- most people have enough moisture already but if you are a dry person then a bit of saliva will do the job.

The battery should last for 70 to 100 burns - this for most of us is more than an entire season’s worth of flying. So you really only need to charge the timer a couple of times a season (unless you are flying A LOT - I’m looking at you, cat glider and TLG flyers). Always charge BEFORE a flying session, you never want to store the timer fully charged. LiPo batteries are happy with 70-80% charge. Storing LiPos with 100% will damage the battery.

The zero or minimum possible time is 5 sec. This is the default time on your timer when shipped. If you program the timer to run for ten seconds it will actually run for fifteen seconds (the default 5 sec plus the 10 seconds you added).

Don’s Cheat Sheet (From Don DeLoach)

1. Long press-> wake up (blue blinks)

2. 3x short presses -> programming mode (solid blue)

3. long press

4. SOLID RED (minutes mode)

5. each short press = 1 min each

6. very long press to go to seconds mode

7. SOLID BLUE

8. each short press = 10 seconds

9. Long press to save this program

10. back to blue blinks (standby mode)

To Fly:

1. one long press-> wake up (blue blinks)

2. one very long press->blue/red flash (timer armed), then release the timer button as you launch the model (timer is running).

3. 3 short presses to stop the timer and return to standby