Difference in Fan Horsepower Costs

[Mike51Merc]

Originally Posted by 36Bill

I always thought that the fan was for still air, when you are stopped. At speed the fan is working in moving air and not doing much work. With a 50mph wind coming into the grill the fan can't being much.

Bill

Good point, Bill. So what you're saying is that if you are driving fast enough, the airflow will actually propel the fan and that will actually add horsepower rather than use horsepower. I guess a four blade fan will add more HP than a three blade fan.

[Roger/Sacramento]

If it is decided to paint the fan powder coating would be better than rattle can paint. Since the stock fan has a sharp edge on the blade powder coating would tend to round off the edge and give a more efficient cut through the air. Somewhat like a propeller. This has not been field tested but, I think the theory is correct.

[rotorwrench]

With forward speed the fan is unloaded a fair amount. That's kind of a counter balance for the amount of work it takes the engine to pull it. It's just one more variable that changes the work it takes to spin one. We wax main rotor blades on the helicopters all the time but it only seems to aid with lift a very slight amount and waxing the top or high velocity side of the blade does help with packing or lift on the high pressure side more if you don't wax the bottom of the blade. We wax them more to keep corrosion in check than for lift or speed reasons. On a little tiny fan it won't even be noticeable.

[Richard in Florida]

Originally Posted by rotorwrench

On a little tiny fan it won't even be noticeable.

Ran a temperature comparison road test today with the four-blade fan. Conditions were the same as they were during the three-blade test including OAT (within 2 degrees).

Overall, engine temperatures ran about 8 to 10 degrees cooler.

However, I can feel wear in one or both of the hub bearings.

Can these bearings be replaced? Are these bearings available, or might there be a new "modern" equivalent? Anybody done this?

[jdl]

Originally Posted by Richard in Florida

Ran a temperature comparison road test today with the four-blade fan. Conditions were the same as they were during the three-blade test including OAT (within 2 degrees).

Overall, engine temperatures ran about 8 to 10 degrees cooler.

However, I can feel wear in one or both of the hub bearings.

Can these bearings be replaced? Are these bearings available, or might there be a new "modern" equivalent? Anybody done this?

the 49-51 Ford and Merc passenger car fan shafts were pressed in the mount. I have pressed one out and found a new bearing at Kaman Bearing ( the shaft and bearing are one in the same, like a water pump bearing) the one from Kaman was a little longer shaft so I cut it to match the old one.(the part # is on the end of the old shaft) look at the back of the fan mount, there is a rubber washer recessed in around the shaft, carefully pick it up and back then you will see a snap ring, remove it, then using a press, press it out from the backside of the mount. when pressing it back be sure to press to the same depth so your pulleys line up. to press the shaft out of the hub, carefully remove the center metal cover (like a little hub cap)from the front of the hub then press out the shaft/bearing by pressing from front of hub towards the back. I know I am long winded but it worked for me (and they said it couldn't be done)..jdl

[Richard in Florida]

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Originally Posted by jdl

the 49-51 Ford and Merc passenger car fan shafts were pressed in the mount.

Thanks, JDL. Very interesting stuff. Not sure I can picture a bearing and shaft being "one in the same."

Aren't there TWO bearings in that hub assembly?

I'd like to save this Mercury hub since my chances of finding another one are slim.

[Vergil]

The first fan bearing I changed I cut the one end to match the one being replaced. On the second fan I changed the bering on I measured and found there is enough room in the housing toward the fan so the shaft fit without shortening the shaft, the thin end cover plug fit with room to spare.

Vergil

[Richard in Florida]

Originally Posted by jdl

...the shaft and bearing are one in the same, like a water pump bearing

Does it look something like this?

[jdl]

Originally Posted by Richard in Florida

Does it look something like this?

Yes, that is similar...the number on the end of the shaft is 885106, the one I got from Kaman bearing is # 885586 NSK brand. this was for the three blade fan.

[ken ct]

Originally Posted by Roger/Sacramento

If it is decided to paint the fan powder coating would be better than rattle can paint. Since the stock fan has a sharp edge on the blade powder coating would tend to round off the edge and give a more efficient cut through the air. Somewhat like a propeller. This has not been field tested but, I think the theory is correct.

LOL,LOL,LOL ken ct.

[rotorwrench]

We refer to those types of bearings as a double row bearing. It has two rows of balls and double ball grooves in each race. Most of them are sealed but many have seals the can be removed for servicing. Those plugs on the front are commonly refered to as Willkie button plugs. We use them a lot in aviation to plug old unused holes in instrument panels and they are made in all sorts of sizes. They are named after Wendell Willkie who used buttons like them in his failed presidential bid.

JDL, thanks for that P/N. My Merc fans are still running smooth but the day will come when they aren't. 60-years is a long time for grease to be in a sealed bearing.

Kerby

[Richard in Florida]

Originally Posted by jdl

Yes, that is similar...the number on the end of the shaft is 885106, the one I got from Kaman bearing is # 885586 NSK brand. this was for the three blade fan.

Thanks for that info.