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Ignition System
Introduction
The V2 Desert Aircraft Ignition module is a microprocessor controlled auto advance/retard system.
The unique timing curve has been developed by Desert Aircraft to provide optimum performance and reliability for your
DA35. This unique curve will provide easy starting, smooth running throughout the rev range and rapid response to
acceleration and deceleration.
With the combination of multiple magnets on the engine hub and a bipolar hall sensor, the microprocessor can measure
the shaft speed and position accurately. The V2 ignition provides consistent safe starting because the module won't spark
unless the propeller is deliberately "flipped" at starting speed. The module will also not allow the engine to start or run
backwards.
Warning! This programmed ignition system may not be compatible with other Desert Aircraft engines.
Mounting
The module is supplied with mounting grommets and eyelets to be used in a similar way they are used to mount servos.
Alternatively the module can be mounted with Velcro straps on a foam/rubber bed. Cable ties (Zip ties) should be avoided
as the hard plastic can damage the ignition module case over time.
Choose a location where the module can sit flat away from heat sources and well away from any receivers or connected
servos. The module will produce a small amount of heat so do not completely enclose it in foam. (The top surface with the
embossed logo is where most of the heat will be radiated from.)
Choose a location that will allow you to route the cables in such a way they will not be damaged.
The sensor cable is provided in a rubber braided sleeve that is resistant to high temperatures and abrasion. There is no
need to provide any additional protection (e.g. spiral wrap) as that will just add mass to the sensor lead putting more strain
on the connections.
The HT cable has an outer silicon jacket to give protection from both high temperatures and mechanical abrasion. Please
take care that the cable is protected from sharp edges (e.g. fiberglass cowl edges) as this will cut through the protective
sleeve and can result in unreliable engine performance. Route and support the cable so that it minimizes the amount of
movement of the cable.
Connection
Three simple connections are all that is required.
1. Push the spark plug cap onto the CM6 spark plug until the hex of the spark plug is covered by the cap outer shell.
The cap is secured by both the outer housing around the plug hex as well as the internal silicon moulding fitting
over the plug top.
2. Plug the sensor lead into the module in the slot marked "SENSOR." A Futaba style lead is used so that it will only
plug in one way. YOU MUST USE A DA TYPE HALL SENSOR FOR CORRECT OPERATION.
3. Connect the battery via your preferred switch (either mechanical or Tx controlled kill switch) to the slot marked
"POWER." Check the alignment so that the polarity is correct. IT IS IMPORTANT NOT TO CONNECT POWER
TO A MODULE WITHOUT A SPARK PLUG FITTED TO THE CAP.
Note about mechanical switches. We have found that toggle switches are un-reliable when subjected to the vibration
typical of a model aircraft. Heavy duty slide style switches typically supplied by the radio manufacturers are better suited.
Battery Considerations
The V2 ignition module is nominally rated for 4.8 to 8.4V dc supply. This means you can use either a 4 or 5 cell nickel
cadmium (NiCad), nickel metal hydride (NiMH) battery, or a 2 cell lithium ion (Li-ion), Lithium polymer (LiPo) or Lithium ion
phosphate (LiFePO4) battery. The module features a constant power convertor to charge the high voltage capacitor. This
will mean the higher the supply voltage used, the lower the current draw from the battery. On the V2 single ignition
module, a 4cell NiCad 1100mAHr battery will give a couple of hours of typical flying with plenty of reserve. A 2 cell Lion
600mAHr will give approx the same running time.
Soft pack LiPo batteries while electrically compatible are not ideal for use in gas aircraft because of their mechanical
construction. Over a period of time, the tab connection to the LiPo cells will not tolerate the vibration experienced by a
typical gas aircraft. We have seen these connections become intermittent resulting in unreliable engine performance.
A reverse connected battery will not damage the module but it won't run and the LED will not turn on. On the other hand if
you allow the battery positive (or an internal cell connection) to come into contact with the engine or the ignition module
enclosure, it will damage the module. We have seen this happen with poor mounting of the battery pack which has worn
through the insulation of the cell letting it touch the engine or module case.
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