Fuel pump and gascolator
The new Buzz Aero wobble pump showed up this last week. It is (close to) a bolt in replacement for the D2 pump that was in my Pitts. The bolt pattern matches and I just had to flip the pump handle 180 degrees to get it to fit the existing mount. I was pretty happy about that until I tried to install the inlet AN fitting. On the D2, the inlet fitting was towards the bottom of the pump when mounted. The new pump has it clocked near the top. Not a big deal, but now it interferes with the front tube on the seat.
I removed the mounting hardware and rotated the pump backwards until the fitting cleared sufficiently. Then I drilled new mounting holes in the existing mount. It was an easy modification and now all the original fuel lines will work correctly. I'll be replacing the hoses when they get re-installed, but it's nice to see everything fit.
I also pulled the new ACS high-pressure gascolator out of its box. It is much shorter than the old part and won't project out of the belly pan. The old gascolator had a good 3-4 inches that stuck out of the bottom of the plane. The new one fits much better and only the end of the Curtis drain valve will be exposed through the belly. I still need to fab up a mount for the new part.
I had one last welding task on the fuselage. There have been harmonic issues on some S1's with the diagonal tube on the bottom of the fuselage in the section behind the seat. It is the longest tube in the fuselage and resonates at frequencies that are reinforced by some power settings. The result can be a crack near cluster welds. The solution is to change the resonance frequency to something higher. I did this by welding in a short 3/8" steel tube between the lower seat back and the diagonal. This raises the harmonic frequency quite a bit. After 30+ years, I couldn't find any cracks, but this will eliminate one possible cause.
I think I've got the fuselage ready for blasting and shooting primer. I need to order a few supplies and then we'll start working through the steel parts until they are all protected again. I'm planning on using the PolyFiber two-part epoxy primer. I'll use white instead of chromate green, since the topcoat for the tubing will be white.
<EDIT> Added pictures of the new pump and the mod for the bottom diagonal behind the seat.
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