RV-8 and the 2026 Condition Inspection, Epilogue
- Steve
- 3 days ago
- 7 min read
To read about how this saga begin, you can look here.
5/30/26 When last we left our intrepid hero, he was contemplating the need to modify the front bulkhead for the spinner. The initial idea on how I planned to do this can be found in this post.
After last weekend's success, all that was left was to get the spinner back on and then go out and see if it will run, and more importantly, see if the prop will cycle. I was more than a little nervous about this operation. At one point, I wondered if it wouldn't be easier to start with a new bulkhead, but after looking at the drawings, I don't think it would be.
The first thing that I needed to do was to determine how much the holes needed to move and in what direction. While I had the spinner on for a test fit, I marked the location of where the holes in the spinner were on the bulkhead flange, and that gave me an indication of what direction it needed to move. After drawing lines from the center of the bulkhead to the center of the screw hole and through the center of the marked new hole location, I was able to determine that the holes needed to move by about one whole hole, in this case, 1/4".
The next thing to do was to make sure I understood on which side of the current hole the new hole should be. With this knowledge, I was still a little leery of making the actual cut. A true sheet metal mechanic would probably just take a Dremel or die grinder, or some other tool holding a rotary file and just free hand the slot. I do not have that ability. I do not have enough practice to control such a tool with any precision.
Based on the post referenced above, I had planned to use a milling machine with a rotary table to cut the groove. For various reasons, I was advised that with the equipment I had on hand, and the limited clamping options I had, this would likely be a bad idea. This left me with the choice of either making a plunge cut with the end mill or using a 1/4" drill to cut the new hole and then use the end mill to clean up the slot.
To avoid having to make a bunch of tool changes, I opted to do the whole process of moving the hole, with the end mill. Since I was still nervous about the actual process, I wanted to make a test piece and try it out before I took a chance on boogering up (technical term) the real piece. I took some scrap material of the same thickness and drilled a 1/4" hole using a drill. I then used the end mill to create a second hole right next to it.
This worked out better than I expected, even though the area under the work piece was not supported and bent away from the tool during cutting. With that giving me more confidence I set up the actual bulkhead as previously described.
As it turned out, this was not nearly a rigid enough set up and as soon as I put the mill to the piece it began to move off of its position. That left me once again going back to the drawing board. I still had no idea how to clamp the bulkhead more securely to the table. After searching through the hangar again, I came up with a very non-machinist solution. It is almost elegant in its non-elegance.
I used simple hardware store clamps to clamp the piece to the rotary table. The big drawback is that with this method, the rotary table would no longer rotary. I got the tool lined up where I wanted it, then attached the blue clamps and then created the hole. From there, I had to remove the blue clamps and reposition the table to get the mill over the bit between the holes to clean that out and then reattach the blue clamps before cleaning that area out. After that, I once again removed the blue clamps and was able to rotate the rotary table to clean out the groove.
After the first two holes were finished, I took the bulkhead back to the propeller to see how it fit and how well it would rotate. The original holes were slightly larger than 1/4", so the 1/4" hole I made was not quite the same size and the bulkhead did not rotate as smoothly as I would like it to. In thus rotating it though, the bolt threads left marks on the bulkhead showing me where I needed to remove a smidge (technical term) more material.
After that, it was just a simple matter of repeating the above processes for the two remaining holes.
Once I had all four slots started, it was just a matter of a few minutes with a file to get the right shape and contour so that it would rotate easily in place. Once that was done, I de-burred all of the holes / slots, and it was ready for initial fit.
Once I test fit it on the prop, I was surprised at how well it fit and how easily it rotated around the slots. From there, I put the bulkhead in what I hoped was a position to be close enough to be able to align the holes once I got the spinner on. I only put the bolts in finger tight so that the bulkhead would still move a little.
I attached the spinner with all of the screws in the rear bulkhead to try to get it as precisely located as I could. I hoped that it would be close enough to allow me to use a pick, or some other tool, to rotate the bulkhead to where it would fit correctly. I figured that I may have to go back the milling machine and enlarge the slots if it wasn't close enough already.
I was stunned to learn that on my first try I was within a couple of thousandths of having it perfectly positioned. From here I carefully pulled the spinner back off and tightened the four bolts holding the bulkhead to the prop. I then put the spinner back on with all of the screws, rear bulkhead first and then front bulkhead. The front bulkhead screws all dropped in perfectly without any need for further adjustment.
I was amazed at how well it fit. I thought I would have to mess with it for a while to get it to fit properly. Of course, now I have to take it off again so that I can safety those bolts.
After that was done, I had to put the spinner back on yet again. The good part is that I shouldn't have to pull it off again until next year's condition inspection.
It is now ready for a test run. After sitting for two months, I hope I can get it started easily.
5/31/26 I started by taking a few moments to look everything over making sure that there was nothing that was missed or left disconnected, or loose. I found no issues so I opened the doors and rolled it outside.
As part of the condition inspection I have to inspect the gascolator, which results in draining all of the fuel firewall forward. After having done such, I often have a hard time getting the engine to start as I have a difficult time determining how much to prime and I usually under do it and have to try a couple of times. This year, for whatever reason, I got it just right the first time and it lit right off.
Since I completely drained the oil system, and then let it sit for a couple of months before adding more oil, there was not really anything in the oil passages, particularly between the governor and the prop. I thought it might take longer than usual to see oil pressure displayed and it did, but only about 15 seconds longer than usual.
You can see a short video here.
After letting it warm up a bit, I taxied out to the runup area to see if I could get the prop to cycle. I had no idea how long it would take for oil to get throughout the system, but by the time the oil hit 90 degrees and I was comfortable running it up,the prop cycled just fine. It seems to be a little different than before, though. Prior to the overhaul, the prop control was a bit touchy, Carl even warned me about it before I first flew it. Moving the prop control back a very small amount resulted in a very large drop in RPM very quickly. It wasn't a problem, once you got used to it. Now, however, it seems that I have to move the prop lever a good bit further back before the RPM starts to drop off. That's probably not a bad thing, but it is different. Time will tell.
After taxiing back to the hangar, I shut down and pulled it back in and looked it over for leaks. Fortunately, there were none. Everything looked good. About all I have to do is put the cowling back on and it should be ready to fly.
It was pretty much all necessary work, but I am glad that it is finished.