I'm replacing (with new)the Fan Blades on my project and there seems to be a difference in the inner edge (back side)of the fan blade to the Fan hub mount distance. Checking a couple of old blades the distance is about 1/4" and the new blade is 3/4"to 7/8". This lets the blade hit the Fan belt even after trying to add two washers between fan arm and hub. I've checked the alinement of the fan hub with the top edge of the pan nose and I'm only about 1/64" or less off alignment. Any Ideas.
Can the new blades be stamped incorrectly causing this problem or am I not seeing something? I've never had this happen before.
Bob
P.S.
The hub is the 20 to 27 style.
Bob
What happens if you turn them over? The pitch would be the same but the offset might be different at the center.
Mark
That would reverse the curve of the fan blade and I don't think it would work that well in drawing in air for cooling.
Bob
I just went out and looked at mine, you are correct.
Pictures:
new fan blade
old fan blade
new fan blade
old fan blade
Bob
Bob,
Looks like your new fan would work on the extend 26-27 hub but not on the standard 21-27 hub.
Jim
The top photo looks like the top blade is closer to the belt then the bottom blade. Do the tips of the blades travel on the same plane? If not maybe one of the blades was stamped wrong. The photo of the pulley that Jim posted, I had the same thought.
Jim And Mark
Thanks for the help. I think the new fan blades will help in the cooling,more air flow.
Will contact the supplier and suggest that a spacer be made available to use with the old hubs, it would appears that there will be more shorter hubs available than the 26-27 longer ones. This would be helpful to the hobby.
Thanks again to the forum.
Bob
Bob, maybe you could find one of these.
Can't you just hand bend the fan blades to the proper position?
Royce
There is a 1" difference, it would ruin the pitch. I found and have in my hot little hand a 26-27 long hub already. Thanks
Jeff
I'm doing a snow machine not an airplane, but thanks any way. Grin.
Bob