Wood prop

Okay, a quick update but unfortunately not the final report.

The W72GK-50;is mounted and it's beautiful. I knew that wooden props are known to be smoother due to their dampening engine pulses, but it is VERY much smoother. I was verifying my RPMs with an optical tachometer and this prop idles butter smooth at 475 RPM. The RPM also accelerate quicker, and it's noticeably smoother at all RPM settings.

On interesting difference from the old McCauley - the black back of the McCauley really disappeared above 1200 RPM. The back of the Sensenich is brighter wood and brass so there's a golden propeller arc that's a lot more visible. I don't think it'll be a problem, but this prop really let me know that it was going to be different.

Unfortunately, it also exceeds the static RPM limit. I had mentioned to Sensenich that I have not a stock c-85 but a c-85 "Stroker" with a little extra horsepower, but they still recommended this as a "cruise" prop so I agreed.

Now, According to TCDS A-718 Propellers Item 2: "Propeller with Continental C-75 or C-85 series engines" ... "any fixed pitch wood propeller eligible for engine speed and power which meets the static r.p.m. and diameter limits as follows: Static r.p.m. at maximum permissible throttle setting: not over 2100, not under 1850. no additional tolerance permitted. Diameter: not over 74 in., not under 72 in."

But I'm getting 2176-2185 on the ground. Waiting to hear from Sensenich about how to proceed. Looks like I'll be going to the 52 or 54 inch pitch but I want to hear from them.

Understood! As my dad was fond of saying, "No good deed goes unpunished". Wood prop with a lithium battery is for later this year or early next year. Adding your notes here to my Squawk list Notes tab.

Much appreciated for everyone who has helped a newbie get up and running!

The TCDS requires careful reading to figure out the propeller stuff. Sometimes the C-75 and C-85 are allowed to have the same prop but at a different diameter and static RPM limits.

Upgrading the C-75 to C-85 is pretty simple... different carb (or a few new parts for the same old carb) and move the redline up to 2575 RPM. That was done on my plane decades ago but nobody ever followed up that the prop was supposed to have been shortened at that time... the prop's been "illegal" for decades!

The shorter prop allows you to get those higher RPM's. I decided to get my prop trimmed, but it got red tagged. That's what I get for trying to become legal.

Thanks Brooks, appreciate the info. One question, on RPMs were there any changes to the RPM limits needed? I am seeing depending on engine and prop you may or may not have to back down or increase max RPM. I'm looking forward to your report! Currently in Annual and dreaming about losing a few more pounds now that the carpet and rudder kit are out.

I ordered a W72GK-50 directly from Senseneich in Florida because they had it in stock. I have a c-85 "stroker" and I hope this turns out to be a good cruise prop. It was Senseneich's recommendation for a cruise prop. Price was $4200 including a new bolt kit and shipping. The best quote I had gotten on a new McCauley 1B90 was over $8000 (!) and even at that price it might take a YEAR to fulfill the order.

The wooden prop, bolts, and skull cap spinner turned out to be 12.3 pounds lighter than my old McCauley, bolts, spinner, and spinner plates. The bolts are different - the wooden prop needs longer bolts.

With that weight loss on the nose, if I were flying solo with full baggage (heading to Sun n Fun or Oshkosh with camping gear) AND I ran the wing tanks dry... Very soon after I started running down the nose tank my CG would move too far aft.

Now really, I try not to ever empty the wings and I could always grab a piece of heavy baggage and toss it on the passenger floor. But in the interest of NOT relying on that while I'm probably getting worried about fuel, I got the Earthx TSO battery and install kit. That saved just over 15 pounds from near the baggage arm. 

Been down with a cold for a couple days but as soon as I have a good weather day and my nose works again, I'll report on the results of the prop and battery. 

Looking forward to it!

Meantime I was wrong, I have the C75, is that what you have? If so which Sensenich did you get and what was the cost if you don't mind? How much weight will it/did it shave off your bird and did you have to adjust anything to compensate for a lighter nose?