Jabiru Motor and AF2500 RPM

[Spriteah]

Hello fellow flyers and builders. I'm having troubles getting the TACHO to work on a AF2500 from advanced flight systems.

 

Has anyone successfully done this? The readings I get are very erratic. Have asked company for assistance and been given several mods but none so far have worked. Curious if someone had successfully done it.

 

Cheers,

 

Jim Tatlock.

 

 

[Captain]

Jim

 

 

 

I've done it on a Dynon but not an AF2500.

 

 

 

Are you taking the signal from the Jabiru (VDO) tacho sender or the alternator wire. (I tried both and prefer the latter).

 

 

 

If the former I suggest you check earthing and clearance from the trigger. If from the white alt wire, check earthing of the system and the instrument itself.

 

 

 

As it's erratic I'd concentrate on checking intermittent contacts and earthing if it was me, and maybe recheck the calibration settings in the instrument.

 

 

 

At least I hope that is some help.

 

 

 

Regards Geoff

 

 

[Spriteah]

Tried Both

 

Thanks for the reply Geoff

 

I have tried both. The company has released several mods but none seem to work. At present I have it off the alternator. But it really is unusable. I have tried earthing different locations. Replace a computer module, rewired.

 

I'm become suspect that it has not been successfully done on this instrument with a jab motor.

 

If anyone knows of it being successfully done please response.

 

Jim

 

 

[Captain]

Assume you have also tested the wires .... but as a last resort, run a quick temporary wire as it is not unheard of that sod's law says you have a bodgie bit of wire, no matter what quality it is .... or maybe that stuff just happens to me.

 

 

 

I have a friend had erratic readings on the tacho in his Dynon with a 3300 engine and the error was somewhere in the yellow/green and red limits that are programmed into the Dynon. Do you do the same thing with yours? (Apologies but I am not familiar with the unit).

 

 

 

[Spriteah]

Can program

 

You can program limits but they should not restrict or cause the display to float. Basically the instrument is looking for a certain type of pulse. The jab motor produces different to the required pulse.

 

Wire ect. are fine and been replaced. Im actually an L2 avionics. Just losing the battle and was hoping someone can worked out a fix. I could put a independant rpm sensor in but messy and not cheap.

 

Any more info greatly appreciated.

 

Jim.

 

 

[Captain]

Apologies if my last suggestions were a bit too basic.

 

To add to that, though, I assume you have also read the exchange on their Forum where a bloke was discussing Tacho set-up on a 3300 which provides the same signal, although this is for the AF3400 instrument. Anyway it is at http://www.advanced-flight-systems.com/forum/viewtopic.php?t=288&highlight=jabiru

 

 

[Guest brentc]

Have you confirmed it with a standard tacho? I get very erratic readings on my standard Jab tacho. The problem lies with the tabs on the flywheel not aligning properly with my sender unit.

 

 

[Spriteah]

Standard Tacho

 

Brent nope not yet. im not using the standard tabs at the min. Both myself and AFS gave up on that concept. I will have a look at the 3400 info it's most llikely the fix/mod I have installed.

 

can anyone recommend good Tacho 2 1/4 inch that will suit the jab 6?

 

Jim'

 

 

[Captain]

can anyone recommend good Tacho 2 1/4 inch that will suit the jab 6? Jim'

Jim

 

 

 

I reckon it's a no-brainer for UMA's unit. I have one as well as the Dynon and it works + looks great.

 

 

 

See them at http://www.umainstruments.com and here is what it looks like in my dash http://www.recreationalflying.com/forum/attachment.php?attachmentid=2017&d=1181461809 I have their 57 mm ASI & VSI as well.

 

 

 

You will see that they have a unit specifically for Jabiru engines also have a take-off to drive a Hobbs unit when above a set rpm.

 

 

 

You can get them via Aircraft Spruce and similar suppliers and they are in their catalogues, but I went direct to UMA and they sent them out in about a week after adding the coloured sectors to my spec.

 

 

 

Hope this helps.

 

 

 

Regards Geoff