Rick Martin
Gold Member
- Joined
- Apr 20, 2004
- Messages
- 2,162
- Location
- BRADENTON, FLORIDA & FL10
- Aircraft
- Everglades Kite Gyro, Tandem Dominator
- Total Flight Time
- 900 hours
Most of the guys who were at Essex days know about this, but I thought I'd share it with everyone:
I arrived early on Thursday. When I tried to fly Thursday afternoon I had three aborted takeoffs. I couldn't get enough climb.
My bee is about 315 lbs, 447 single carb, 60 Ivo, me at 220 lbs.
Even with this situation, all of you know I fly fine at Wauchula in the heat(I'm guessing Wauchula is about 150' ASL).
Scott's field is at about 800' and was hotter than home.
We took out a half turn of pitch (increase engine rpm). I waited until the next morning and flew but it was marginal.
Later that day the heat caused the same problem. My tiny tach had just died so we were re-pitching blind until Ron showed up with his optical tach.
So we used his tach and pitched it to 6500 static......my usual static is 6250-6300. So we thought......this should do it! It was a dog! I couldn't fly it. He couldn't fly it.
All we could think of was that we had taken out too much pitch..........so we put two and a half turns back in and ............problem solved (sorry but i don't think we took another reading). We both had a good time flying it. It still didn't climb like Barry's 503, but it was adequate.
Scott and I were still scratching our heads so I told him when I got home, I would fly at Wauchula without changing anything and give him a report. Here is what I sent him this evening:
--------------------
Sorry Scott,
I forgot to get back to you about this.
After fitting a temporary fuel tank (I think I told you mine had a hole in it when I got home) and three of us looking the Bee over very carefully, I flew at Wauchula without adjusting anything. It was about 90 degrees and humid with a bout a 5 mph head wind. The old girl leapt into the air and flew as good or better than she ever has on a cool morning here....very good climb. The engine rpm said 6250 to 6300 on climb out. This is lower than normal for here. I usually turn about 6350 to 6400.
So I guess the logic works....................if it's set for best performance at a higher density altitude then it will fly better at a lower density altitude. I have flown well two days in a row, so it wasn't a fluke. By the way I was discussing this reverse-logic phenomenon (higher engine rpm is supposed to give better thrust) with my friend K.C. who flies a fixed wind 912 with an Ivo. He confirmed that it was fairly common knowledge that you can go too far with taking pitch out of a prop (to hell with the suggested engine rpm). So I guess the best indicator is to just do a thrust test for each new set up. I doubt whether running/cruising etc at anything over 5000 would cause the engine to load up.......................tell me I'm correct please and have no concerns here.
I arrived early on Thursday. When I tried to fly Thursday afternoon I had three aborted takeoffs. I couldn't get enough climb.
My bee is about 315 lbs, 447 single carb, 60 Ivo, me at 220 lbs.
Even with this situation, all of you know I fly fine at Wauchula in the heat(I'm guessing Wauchula is about 150' ASL).
Scott's field is at about 800' and was hotter than home.
We took out a half turn of pitch (increase engine rpm). I waited until the next morning and flew but it was marginal.
Later that day the heat caused the same problem. My tiny tach had just died so we were re-pitching blind until Ron showed up with his optical tach.
So we used his tach and pitched it to 6500 static......my usual static is 6250-6300. So we thought......this should do it! It was a dog! I couldn't fly it. He couldn't fly it.
All we could think of was that we had taken out too much pitch..........so we put two and a half turns back in and ............problem solved (sorry but i don't think we took another reading). We both had a good time flying it. It still didn't climb like Barry's 503, but it was adequate.
Scott and I were still scratching our heads so I told him when I got home, I would fly at Wauchula without changing anything and give him a report. Here is what I sent him this evening:
--------------------
Sorry Scott,
I forgot to get back to you about this.
After fitting a temporary fuel tank (I think I told you mine had a hole in it when I got home) and three of us looking the Bee over very carefully, I flew at Wauchula without adjusting anything. It was about 90 degrees and humid with a bout a 5 mph head wind. The old girl leapt into the air and flew as good or better than she ever has on a cool morning here....very good climb. The engine rpm said 6250 to 6300 on climb out. This is lower than normal for here. I usually turn about 6350 to 6400.
So I guess the logic works....................if it's set for best performance at a higher density altitude then it will fly better at a lower density altitude. I have flown well two days in a row, so it wasn't a fluke. By the way I was discussing this reverse-logic phenomenon (higher engine rpm is supposed to give better thrust) with my friend K.C. who flies a fixed wind 912 with an Ivo. He confirmed that it was fairly common knowledge that you can go too far with taking pitch out of a prop (to hell with the suggested engine rpm). So I guess the best indicator is to just do a thrust test for each new set up. I doubt whether running/cruising etc at anything over 5000 would cause the engine to load up.......................tell me I'm correct please and have no concerns here.
