Looking at changing my prop to get a little better performance. The TC for the Luscombe only allows me to use a McCauley 1A90 with a max diameter of 71 inches. Currently I run a 7151. The TC does allow any wood propeller that meets static rpm requirements; of course the proper ground clearance has to be maintained so that leaves me with a make length of about 74inches.

Am I going to gain anything by going to a longer wood prop? I contacted Flight Resource and found out that the fixed pitch MT props are certified as wood so I could go with a MT. Too bad their MTV-1 is certified as a constant speed instead of an "adjustable pitch."

This is what the TC says about wood props:

Propeller - wood (fixed or adjustable pitch) (Models 8A, 8B, 8C, 8D, 8E and 8F)

Pretty open...just has to be a certified wood prop.

Whee,
Performance wise I don't think you will see any improvement.
It will take 11 lbs off the nose and run smoother and if you wreck it you'll have
Kindling for a fire.
I went with wood on the Vagabond for weight and looks.
Dave

What horsepower is that Luscombe? From the prop diameter & pitch you cite it must be an 85 or 90? Looking at the Univair catalog, a 72" Sensenich wood prop (W72GK-48 or 50) is approved . A friend of mine tried a couple props on his 65 horse 8A, and the best performer was a Sensenich wood. One side benefit besides lighter weight is (maybe?) no engine teardown if you ever have a prop strike. The downside is that they're harder to handprop due to less momentum, if you don't have an electric system.
Looking at the Sensenich metal catalog, I don't see anything listed for a Luscombe but I do see the 76AK-2-42 (74" diameter) listed for the 85 & 90 horse Cubs. Might be possible to get it approved with the 85 or 90 on your Luscombe?

Mine is 85hp. I really don't want to have to get approval for anything; I just want to put it on and be legal. The McCauley 1A90 is the only approve metal prop for the 8E. I have a friend with a 8A than he only uses wood props. He is kind of a collector, last I talked with him he had about a dozen props. If he wasn't across the state I'd go see him and try a few.

Where the TC allows any wood prop to be used and it says "adjustable" I thought a ground adjustable MT might be a good option. But I've also heard that wood props aren't as efficient as metal so I'm not sure there will be any benefit aside from weight.

Interesting side note: A Beech Controllable Pitch prop was approved on the 8A 8C and 8D.

You can see the crank to adjust pitch on the upper right of the panel:

If the MT or other "modern era" wood props have well-designed composite tips, then the tips might possibly be as thin at the tip section as a metal prop, which then might mean you would get similar performance out of it as a metal prop.

A standard wood prop (Sensenich etc.) is thicker at the tip for structural reasons, giving you a thick airfoil which is inefficient and makes a lot of drag. Imagine a big ugly 2X over-thick Clark Y airfoil trying to fly at .8 Mach... lots of drag, which on a propeller means more engine HP used to overcome that drag. This thickness problem could easily take away any added thrust from a larger diameter or weight benefit.

However if you find that the MT props have a wood core that tapers off to a solid composite section out near the tip, and is thus a much thinner airfoil in that critical region - you might get the advantages of both wood and metal.

whee, I had a cub 85hp with a 1B90 and my buddy had a cub 90 hp with a wood sensenich. He borrowed my metal 1B90 and instantly gained 7 mph. That's quite a bit for a cub. I didn't try his wood on my 85 cub. Just a little input from the Piper side of things.

When it comes to a wood prop, think 1/2. If you buy a used one its only worth 1/2 or less of a new one, and if you buy a new one and put the crush ring mark on it torquing it up, its now only worth 1/2 of what you paid for it even if you only put 1 minutes worth of time on it. Know what your doing before you buy one. doug

When it comes to a wood prop, think 1/2. If you buy a used one its only worth 1/2 or less of a new one, and if you buy a new one and put the crush ring mark on it torquing it up, its now only worth 1/2 of what you paid for it even if you only put 1 minutes worth of time on it. Know what your doing before you buy one. doug

So I pay 3k for a MT, find out it sucks and can only sell it for 1500. That does not sound very good. Thanks for the tip guys.

c-ed, I'm guessing you no longer have the cub?? would be nice to find some guys around here to fly with.

sold the cub in 2004, the best flying there is. Am now flying a tripacer. More comfortable, but not as fun as the stick in the right hand and the throttle in the left.