gfeher wrote:My '52 B model has its original legs and I am considering the P-Ponk mod. I don't want to re-open the P-Ponk mod debate as I understand how it is installed and works, and the debate has been thoroughly aired in this thread and others. However, I have a question about the P-Ponk mod that relates to the original legs vs the lady legs vs the 180 legs that was touched on in this thread above but is still not clear (at least to me). Are the lady legs or 180 legs thicker than the original legs in the gear box area? Because the P-Ponk blocks install directly on top of the gear legs in the gear box, it appears (at least to me) that if the mod is installed with original legs, the original legs cannot later be changed out for legs that are thicker in the gear box area (without modifying the P-Ponk blocks). Is this correct? If either the lady legs or 180 legs are thicker, by how much over the original legs? I'm not convinced that I will ever change my gear legs to lady or 180 legs. I just would like to know the facts ahead of time.
Thanks in advance.
It's my understanding that the early legs and lady legs are the same thickness. It looks like early model 180 gear legs are the same thickness as 170 gear.
My recollection from many years ago when we installed the pPonk reinforcement, is that they suggested placing a washer (or shim) between the top side of the gear and the pPonk bracket. This would give the ability to change gear, or adjust lateral leveling.
Ryan, thanks for that link. It's very helpful. From it, I looks like (at least nominally) the original legs ("The Early 170 Gear") are 5/8" thick but the lady legs ("The Late 170B Gear") and the early 180 legs are 11/16" thick. But the ranges of all three versions overlap, so much so that the upper range of the original legs is the same as that of the lady and early 180 legs. I'm not sure what to make of that.
Sfarringer, the P-Ponk installation drawing and instructions I have seen do not show or mention use of a washer or shim under the block. But that makes sense. The problem I now see from Ryan's link is how much to allow for a shim or washer given the broad ranges of thicknesses mentioned above.
John Renwick
Minneapolis, MN
Former owner, '55 C-170B, N4401B
'42 J-3 Cub, N62088
'50 Swift GC-1B, N2431B, Oshkosh 2009 Outstanding Swift Award, 2016 Best Continuously Maintained Swift
I just got off the phone with Steve at P. Ponk, who was very helpful. Here's his explanation: The P. Ponk gear mod blocks were designed to allow for a later switch to thicker gear legs, such as 180 legs, without any reduction in the strength of the blocks. At the time you switch to thicker legs, you just remove the blocks, and on each block, machine down the surface that contacts the top of the gear leg just enough to accommodate the actual thickness of the new gear leg. Then replace the blocks. The way the radius is cut on the ends of the surface that touches the top of the gear leg shows that extra material is provided on this surface to allow for machining it at a later date.
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