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The benefits of three blades over two.

It has been a very wet Spring with little sunshine and wind lately to dry things out, I believe lots oft French Grass strips are in similar states this spring.
My base has been usable 90% of the time, it’s just all the water in the air that’s been a problem as in I can’t see through it

They don’t have to fly to grass Or indeed fly to an airport. I rarely fly to airports. I mostly just land there and go somewhere else. Maybe one could add “grass grows faster” to the negative points in that thread…

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

It looks like 93.75% of UK grass

The staff attitude is also not wholly unfamiliar…

And you wonder why European pilots don’t want to fly to the UK ?

That’s why I generally avoid grass; there are just few known grass airfields where I land and even that is very rare.

LDZA LDVA, Croatia

It does have a small 6” wheel but I believe it would have to be significantly larger to have provided a different outcome. Tricycle undercarriage with 70 litres of fuel just behind the fire wall is a bit of a problem on sodden ground.

Last Edited by Stickandrudderman at 12 Apr 05:53
Forever learning
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@Stickandrudderman would you be comfortable sharing with us size of the front wheel in your aircraft?
The image you posted is kind of striking

Last Edited by Robin_253 at 12 Apr 04:11

This is one advantage 3-blades have over 2-blades. The increased ground clearance is often only about 1 inch, but that 1 inch may indeed do the trick. But the smaller diameter and is not always there. Many years ago, a local flight school had a 2-blade Bonanza equipped with a 3-blade, and it was found to have exactly the same diameter as the old 2-blade, so no increased ground clearance and actually slightly more propeller noise.

I opposed going 3-blade a few years ago, when our syndicate 2-blade Piper Dakota had a prop strike and needed a new prop. I feared reduced cruise speed (theoretically you get that from adding more blades), saw no need for improving the already satisfactory take-off and climb performance, and saw no reason to add 8 kgs of empty weight about 2 metres in front of CoG. In the end we had the 3-blade, which because of better aerodynamics (scimitar profile) did not impair cruising speed, did improve vibration a little bit maybe, never made me think any more of loading than before, and improved ground clearance by one inch. It might also slightly have improved the ability to do steep approaches and reduce float during landing round-out, but that also means it will not glide quite as well in case engine failure, I guess. The noise footprint should be slightly smaller but we have no measurements and the low-RPM Dakota is not very noise in any case. Everyone says it looks better (some say “sexier” although I find it awkward using that word about a Dakota) and that it definitely will make a resale easier. Overhaul will even be slightly less expensive with the 3-blade because of longer intervals (that was what tipped the scale for me in the end).

But for an aerodynamics purist, the 2-blade will be the right choice for speed, at least for low-Mach-number piston aeroplanes. Just look at early big-bore Mooneys and Malibus.

Last Edited by huv at 11 Apr 08:21
huv
EKRK, Denmark

It looks like 93.75% of UK grass

The staff attitude is also not wholly unfamiliar…

A good outcome though. My TB20’s prop would be several inches underground in this situation, and a second £20k…

Administrator
Shoreham EGKA, United Kingdom

It looks like swamp :(

LDZA LDVA, Croatia

EGTB

Forever learning
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