Prop tip clearance for various props/gear leg length?

I did a forum search but didn't find anythng relevant. I also looked on the Van's web page...nothing obvious there.

What is the prop tip clearance for the following configurations:

Short Gear legs:

68" prop
72" prop

Long Gear Legs:

68" prop
72" prop

If engine and CS vs FP prop matters then:

IO-320

C/S

If mount matters (e.g. dynafocal I etc) and you only know the stats for a particular mount

or if you only know the stats for a 360, please share those.

I'm trying to get an idea of the range.


Many thanks!

Size matters...

Saville said:

I did a forum search but didn't find anythng relevant. I also looked on the Van's web page...nothing obvious there.

What is the prop tip clearance for the following configurations:

Short Gear legs:

68" prop
72" prop

Long Gear Legs:

68" prop
72" prop

If engine and CS vs FP prop matters then:

IO-320

C/S

If mount matters (e.g. dynafocal I etc) and you only know the stats for a particular mount

or if you only know the stats for a 360, please share those.

I'm trying to get an idea of the range.


Many thanks!

Click to expand...

Saville,
My RV4 has short gear and over the years I had Eight different props on her. I found on the short gear that 69" diameter was perfect yielding roughly one foot of clearance in level flight. I frequented many rough turf and gravel runways over 10 years of flying and never had grass stains or chips present. My 1989 builders manual even gave a recommended prop diameter range. The factory cautioned any prop diameters over 70". Long gear came along in the mid-90's and solved the issue.

A short gear RV4 with a 74" Hartzell is another story altogether. One of my Squadron mate's short gear Four with an 0-360 /Hartzell square tip had to be careful on my rough grass strip, three point landings only. Slightly less than 6 inches is roughly the clearance in level flight attitude. The blended airfoil has the same diameter.

Long Gear on the RV4 is a no-brainer, much better clearance, takeoff angle of attack, aesthetics...etc for many different engines and props, especially the Hartzell 74".

My advice for a short gear Four is an 0(IO)-320 with 9.0:1 comp, flow matching, Electronic IGN and a Catto three blade or a 69" 2 blade. Keep it under 1000# EW and Bob's your Uncle...

V/R
Smokey

smokyray said:

Saville,
My RV4 has short gear and over the years I had Eight different props on her. I found on the short gear that 69" diameter was perfect yielding roughly one foot of clearance in level flight. I frequented many rough turf and gravel runways over 10 years of flying and never had grass stains or chips present. My 1989 builders manual even gave a recommended prop diameter range. The factory cautioned any prop diameters over 70". Long gear came along in the mid-90's and solved the issue.

A short gear RV4 with a 74" Hartzell is another story altogether. One of my Squadron mate's short gear Four with an 0-360 /Hartzell square tip had to be careful on my rough grass strip, three point landings only. Slightly less than 6 inches is roughly the clearance in level flight attitude. The blended airfoil has the same diameter.

Long Gear on the RV4 is a no-brainer, much better clearance, takeoff angle of attack, aesthetics...etc for many different engines and props, especially the Hartzell 74".

My advice for a short gear Four is an 0(IO)-320 with 9.0:1 comp, flow matching, Electronic IGN and a Catto three blade or a 69" 2 blade. Keep it under 1000# EW and Bob's your Uncle...

V/R
Smokey

Click to expand...

So then it sounds like a long gear with a 72" prop is also good.

original info from Vans

Since the builder of my RV4 seems to be the most detail oriented person ever, I looked in his 4" thick POH, at section on landing gear. He had this original vans newsletter article in there talking about the taller gear legs. Of all the discussion I have seen on this topic I have not yet seen this info straight from vans, so I thought I would post it here. The pertinent info is boxed in with highlighter.