Ignition modules 6-4-1 pin to IgniTech modules

The Ignitech unit soft start works by retarding the ignition a further 6 degrees below 1000rpm.

The ignition delay at idle is programmable, and you can reprogram it yourself with the ignitech software ,the ignition curve over the entire operating range will then be displayed on your computer.

I do not advise you to explore this curve elsewhere than on a test bench because at 5800 rpm ...the plane immobilized, it scares me !

We took advantage of an engine not yet installed in an airplane to test different curves, but disassembling an engine Just to test different curves on a test bench is a big job!

Testing the idle curves of an engine in place on an airplane is easier, and often on this point that many of our friends have tried but, they all returned to the curves sold by Ignitech

you can also modify the curve beyond idle, (for example at 3000 RPM), but be aware that the modules are programmed by Ignitech for a Rotax engine with the correct curve, as it exists on Ducati ignition modules sold by Rotax.

We tried different curves, and got a lower idle (1100 RPM ) with a motor that runs very well , but the gearbox doesn't like it at all !!!

We therefore returned to the original curve, the one programmed for sale by Ignitech

Attachement : a photo of our inspection hatch, cockpit side, on which the modules are placed

Jacques

Kevin Stewart wrote:

The Ignitech unit soft start works by retarding the ignition a further 6 degrees below 1000rpm.

Thanks Kevin, so if I look at the table on page 260 of the latest Heavy Maintenance Manual (Rev. 5), which says 4° Before TDC or 3° After TDC, depending on which fly wheel hub (I sure don't have the latest 966872), that means 4° BTDC + 6° = 2° ATDC or for the new hub 3° ATDC + 6° = 9° ATDC. (when starting of course)  Is that correct?

Thanks Jacques, I will sure leave it like I get it ?

Walter Abrahams wrote:

Kevin Stewart wrote:

The Ignitech unit soft start works by retarding the ignition a further 6 degrees below 1000rpm.

Thanks Kevin, so if I look at the table on page 260 of the latest Heavy Maintenance Manual (Rev. 5), which says 4° Before TDC or 3° After TDC, depending on which fly wheel hub (I sure don't have the latest 966872), that means 4° BTDC + 6° = 2° ATDC or for the new hub 3° ATDC + 6° = 9° ATDC. (when starting of course)  Is that correct?

Use caution on going too far ATDC.
Remember that these are wasted spark ignitions, (Almost all engines are)
When a plug fires at 6° BTDC in the Compression Stroke, its counterpart is firing at 6° BTDC in the exhaust stroke.  Not a problem.

When a plug fires at 9° ATDC in the Power Stoke it produces a nice soft ignition that just follows the piston down. The SOFT Start.

However, that also means that its counterpart plug is firing at 9° ATDC in the Intake Stroke and has the opportunity to light off the incoming fuel mixture all the way back to the carburetor.

At 3° ATDC the incoming fuel may not have gotten much past the intake valve but by 9° ATDC it may occasionally make it to the firing plug.

If you start getting carburetor backfiring, you have reached the point of Too Much of a Good Thing.