I am building a Cruzer with a 4th generation Jabiru motor.  I am also installing a Whirldwind 2 blade prop,

( model GA-J2B) which is no longer in production.  The Whirlwind installation manual instructs to bolt the prop hub to the flange or spacer if a spacer is required.

I cannot find anything from Zenith nor Jabiru regarding mounting the prop on a Jabiru motor.  I have no idea if a spacer is required or not. I’m guessing not, but this isn’t something one should guess at…..

Anyone out there that has this combo that can fill me in?


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I think spacers are typically used to adjust cowl clearance.  If you haven't fitted your cowl yet, you likely can adjust the length of the cowl so that you have a clearance gap between the cowl and the spinner backplate.  If you've already fitted your cowl, mount the prop and see if you have adequate clearance.  Scott Matthews, an Aussie Cruzer builder, has a You Tube video on fitting the cowl and spacing the prop.

Mounting the cowl (on a STOL 750) and spacing the prop is also covered in the Jabiru FWF Installation Manual: 35563333.pdf

If a spacer is required, I'd definitely talk to the prop manufacturer to see if they have them available or if there are limitations.  Sensenich was very helpful when I fitted my Sensenich prop to my Jab 3300 and STOL 750 years ago and had to use a spacer.



Thank you.  I'm not sure what you are saying.  My cowl would be long enough with or without a spacer.  The Panther that I built had a 1 1/2 inch spacer that attached to the prop flange and it fit under the cowl.

Was there another reason you used a spacer? Weight and balance? Prop manufacturer recommendation?  Appearance?

Something else?

Thanks for the links, I will check them out.

Was there another reason you used a spacer? Weight and balance? Prop manufacturer recommendation?  Appearance?

Something else?

After fitting my cowl, I just felt the gap between the cowl and the spinner back plate was just too tight and added a thin spacer to give a bit more clearance.


I just watched the video.  Exactly what I was looking for. Thanks!

The video is great.  Just how I fit my Gen 4 Jabiru with the Whirlwind Prop to a CH750 STOL.  If you have the Arion Aircraft cowl and FWF kit, just keep fitting and you will get it to work.  

Thanks.  Kind of how I fit my Panther cowl, but I am thinking of trying piano hinges this time.


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