Cowl Prop Clearance

[Pavel]

I'm installing the cowling on my Long-EZ here, and need to cut the trailing edge to size.

What would the most recent recommendations be, how much of a clearance do I want in-between the cowls and the prop?.. 🤔
 

[zolotiyeruki]

I don't have any knowledge to share, but I just have to say:  That cowl looks amazing!

[jridge]

Did you build that cowl or is it from Featherlite?

[Pavel]

These are the "Melville Cowl Set" from Featherlite, indeed.
Ref.: https://aerocomposites.aero/the-hangar-price-lists/#Long_EZ
 

[Pavel]

From what I've been able to find on the internet, 3.5" clearance seems to be a reasonable starting point... 🤔

[Kent Ashton]

4 hours ago, Pavel said:

From what I've been able to find on the internet, 3.5" clearance seems to be a reasonable starting point... 🤔

I can't swear to it but I don't think it matters much.  I would guess an 1" should be fine.  I think my Cozy is about an inch to 1.5".  Here are a few http://www.briansplane.com/2016/07/     https://www.longezpilot.com/N6PC page4.htm   http://www.freeflightcomposites.com/the-krossfire

It is helpful to go to Google Images for this kind of question or even better Google Verbatim then Images to see what others have done.    https://www.google.com/webhp?tbs=li:1    That's where I found these

Edited October 20, 2022 by Kent Ashton

[slk23]

I reshaped and extended my cowling and have approx. 1" clearance between prop and cowling trailing edge.  No problems with resonances or any other negative effects.  I was hoping it would help cooling while taxiing and that is indeed much better although I can't say how much of the improvement is due to the reduced prop clearance vs. the new baffle seals.

Pavel, take a look at my cowling some time 😉  KLVK #355

[Pavel]

Additional deciding factor, for those of us having exhaust pipe ends inside the cowl, how much of a clearance do we need in-between these pipe ends and the trailing edge of the cowling?.. 🤔

I took measurements at three Long-EZ's here on the field, here are the numbers:

• Plane 1: Prop-to-cowling: 5.50"; pipe-to-cowling: 1.50".
• Plane 2: Prop-to-cowling: 5.75"; pipe-to-cowling: 1.00".
• Plane 3: Prop-to-cowling: 3.00"; pipe-to-cowling: 3.00".