Since getting the Apache flying I have wanted to test the cruise speed for max cruise. The book says about 6500′ with 75% is going to give the max cruise speed. However, every time I tried to test there were clouds at that level or it was just too bumpy. So yesterday I had the perfect day to check it out. I had a buddy that was a 727 pilot go with me and we went out to check the Apache for best speed. We climbed up and I was beginning to think it wasn’t climbing as fast I would expect. I set up cruise power and thought maybe an engine was running a little rough but nothing seemed wrong. Checking the speed I could see it was not giving me as much as I expected. However I still couldn’t figure out what was wrong. After getting back I did my figures. I had taken speeds on the 4 cardinal headings and came up with an average ground speed of 156.5 mph. While not terrible it was not what I expected and I was pretty deflated. Driving home I was trying to understand what the issue was. I thought that if I was in my Airbus I would have thought the issue was my landing lights extended as they will “rumble” a bit and take a very slight performance hit. I don’t have lights that extend, not even cowl flaps.
Then I realized what the problem was, the door was causing the drag! When we taxied out I had mentioned to my buddy that the door handle should come up further. He pulled it up but it didn’t go up any more. I made sure the top latch was good and we went. While climbing I saw the top latch had let go so I again pulled it closed and it stayed shut. However, I later understood he had never gotten the main latch closed, just the “click” latch. So the door had been slightly “in trail” and caused the rumble and extra drag. Just a little but that was enough.
So back out today and I did some more tests on my own. This time I made sure the door was totally shut closed! Climb felt great and with the same test parameters (6500′ @ full throttle-23″ & 2400 rpm) I got 162.5 mph. This was more what I had expected. Then going to 2300 rpm it only dropped to 160.25 mph. I then climbed up and tried 8500′ with full throttle-21″ & 2300 and got an average of 156.75.
So for now I’m happy with the speed numbers I’m getting. I’ll keep track of what I get at cruise when we go somewhere but for now I will claim a “top speed” of 140 KTAS. Or maybe 160 mph since it sounds faster!
Of course I have a few things planned for the future that may add a little more speed yet. So maybe I can get to 145 KTAS 😉
BTW, the book says I should get 175 mph as the top cruise speed. I don’t know if ANY 150 hp Apache (including the test plane!) ever got that speed but mine is never going to! That is why I am doing these speed runs, so I can know what to expect from my antique Apache as it is now.
Gascolator drains are now fixed and don’t leak any more. Door will shut and latch but we need to fix the lock for the handle. New battery and master relay have made starting the engines a totally new experience! The props are turning twice as fast as they were before. My mechanic said he also tightened up some loose connections. It made all the difference. I still plan on installing the copper Bogert cables this winter. The “new” throttle knobs are great. They look and feel much better!
No pics of the “speed runs” since they are pretty boring but I am including one of my nosewheel (super exciting!) since I I totally nailed pushing the plane into the hangar and getting the nosewheel into the alignment box. I use a golf cart to push it in and it has been a slow process for me to learn how to control it.












