Safety Officer Posted September 29, 2011 Report Share Posted September 29, 2011 Take a look at the new prop blog by our Safety Officer. Link to comment Share on other sites More sharing options...
Flying Bozo Posted September 30, 2011 Report Share Posted September 30, 2011 While we are on the subject of props, can anyone fill me in on the difference between the three blade and the red two blade? I have the three blade on my CTSW but hear that the red two blade is better in cruise. Any truth to that. Thanks, Larry Minch Flying Bozo Link to comment Share on other sites More sharing options...
Jacques Posted September 30, 2011 Report Share Posted September 30, 2011 I had the red Neuform 2 blades for 120 hrs. I went for a 3 blades not Neuform and now have the ''standard'' white Neuform 3 blades. Not much difference in speed but a bit smoother that the 2. This is with a 2005 CTSW with the 80 hp. Link to comment Share on other sites More sharing options...
Flying Bozo Posted September 30, 2011 Report Share Posted September 30, 2011 Thanks for the comments Jacques, I have the three blade on there now and have a new two blade in the box. Wondering if it is worth it to swap them?? Larry Flying Bozo 2006 CTSW 100 hp rotax Link to comment Share on other sites More sharing options...
wlfpckrs Posted September 30, 2011 Report Share Posted September 30, 2011 I've heard that the 3-blade is supposed to be smoother. Link to comment Share on other sites More sharing options...
Flying Bozo Posted September 30, 2011 Report Share Posted September 30, 2011 Wlfpckrs, Thanks for the comment on smoother. I think that the three blades are thought to be smoother on all types of airplanes and I suppose that is true with the CT also. I wish that someone might have tried both of them and compared the difference in performance if that is possible. Larry Flying Bozo Arizona Link to comment Share on other sites More sharing options...
Roger Lee Posted September 30, 2011 Report Share Posted September 30, 2011 I have been testing props for the last two weeks. The Warp Drive 3 blade, the Neuform 3 blade and the Neuform (red) 2 blade fly the same speed flat and level provided they all have the same WOT rpm and climb is reasonably close. I have tested these side by side. The 3 blade on all of these is smoother than the Neuform 2 blade. I'm testing the Sensenich 68" 3 blade. It is smooth and at WOT with the same rpm as the others flies the same speed. The one big issue I have with the Sensenich is I loose 250 rpm in climb. The other props get approximately 4950 at take off side by side, but the 68" Sensenich only gets 4700-4720 rpm. The other props all out climb this Sensenich 68" prop. I have contacted Sensenich and they are going to send me a shorter prop for testing. Right now I'm not impressed with the 68" Sensenich which FD is putting on the new LS's. I think they should drop back to the 66". Link to comment Share on other sites More sharing options...
Flying Bozo Posted September 30, 2011 Report Share Posted September 30, 2011 Hi Roger, Thanks for the comments. I have the 3 blade and after your test results I will stick with it. It is smooth and gives me a good climb too. On another note are you and others going to Cooledge breakfast on this Saturday (Oct 1 )morning. I was there one other time before I had the CT and noticed that there were about 4 CTs there. I am going. Another note, I have been running the flaps in the manual position because I like the ability to choose a deflection that suits the conditions and after takeoff "milk" the flaps off rather than the dump that I get when I go from 15 to zero. I assume that since that is in the airplane manual I am not doing any harm to the electronics. Do you have any experience with that or think it might be harmful in some way? Larry Minch Cottonwood, AZ Flying Bozo Link to comment Share on other sites More sharing options...
Roger Lee Posted September 30, 2011 Report Share Posted September 30, 2011 Hi Larry, I'm out of town until Saturday afternoon. I can't make this Coolidge fly in, but next month will be okay. Manual flaps shouldn't hurt anything. I don't think it is really necessary. Link to comment Share on other sites More sharing options...
Flying Bozo Posted September 30, 2011 Report Share Posted September 30, 2011 Roger, OK on Saturday. Will miss you then and also the next one since I will be out of town. Larry Minch Flying Bozo Link to comment Share on other sites More sharing options...
Runtoeat Posted September 30, 2011 Report Share Posted September 30, 2011 A few observations from recent "tuning" of my Neuform 3 blade prop. The first thing I have done is to make a simple fixture which accepts a quality digital level that provides a consistent way to compare the individual blade angles with each other. The digital level gives me accuracy to .1 of a degree. This provides consistent angles for all 3 blades. By doing this, I have noticed a significant improvement to engine smoothness while at cruise. Recently, I also had my prop balanced. I was surprised that the Neuform had imbalance and required offsetting weight. This balancing gave me additional improvement for vibration when combined with equalization of the blade angles. Link to comment Share on other sites More sharing options...
chanik Posted September 30, 2011 Report Share Posted September 30, 2011 I basically did the same thing with the TLL-90E digital level described in the Sensenich prop thread, but I just used rubber bands to hold it to the prop backside. One blade was off by 0.3deg compared to the other two but I hadn't been noticing vibrations. I'm better than 0.2Deg now but seems just as smooth. I don't know what offset it takes to see noticable vibrations or how accurate the manual portractors are. Link to comment Share on other sites More sharing options...
Runtoeat Posted October 1, 2011 Report Share Posted October 1, 2011 Kurt, one of my blades had .8 degree more pitch than the other two and I was running at 5850 rpm at WOT cruise. Before I evened up the pitch of the blades, I would notice vibration when there were gusty wind conditions that came from the rear quarters when on the ground and when pulling back power and slowing down during flight. Equalizing the pitch on all the blades eliminated this vibration. After evening up the blades and flying the CT for a few days, I increased the pitch which brought the engine RPM down to 5500 rpm WOT at cruise. The fixture I made allows me to use the digital level on the edge of each blade to insure each blade is level before setting the pitch. Once the blade has been leveled, the fixture is used to locate the digital level at the same distance out from the prop hub for the 3 blades and aligned vertically on the back side of the 3 blades. If the digital level is not held at the same vertical position on each blade, and instead is allowed to rotate while being held on the backside of the blade, the pitch angle measurement will vary. Link to comment Share on other sites More sharing options...
chanik Posted October 1, 2011 Report Share Posted October 1, 2011 Yeah, 0.8Deg seems like alot. This is a dual axis protractor so I could have used it that way to achieve normal to ground, but really I found that my most repeatable measurement technique was to level the blade to the horizon with the protractor, band it onto the blade at the exact distance, which I pencil marked on each blade, and then use its integral laser to aim at the same point I marked on the ground to ensure there was no side tilt to the protractor. Link to comment Share on other sites More sharing options...
Runtoeat Posted October 1, 2011 Report Share Posted October 1, 2011 Kurt, hitting the spot on the ground with the laser is a good method. If one doesn't realize that it is important to consistently hold the level in the same orientation vertically, as your method and mine do, they won't get repeatable pitch angle readings. Link to comment Share on other sites More sharing options...
chanik Posted October 1, 2011 Report Share Posted October 1, 2011 True, but it is a weak contributer to error. Basically the error from an offset on the 'roll' axis of a protractor is proportional to cos(theta) times the actual pitch angle. So at 0 Deg or normal to the ground, it is the maximum which is the true pitch angle but even with a large 5deg sideways error it is only lower by 0.4% or about 0.1Deg on a ~20 deg pitch angle. Link to comment Share on other sites More sharing options...
Runtoeat Posted October 1, 2011 Report Share Posted October 1, 2011 Kurt, I'm not sure we're talking about the same movement of the level? I would not call the movement a "roll" axis. I would call it more of a pivoting (clocking?) of the level while it is being held against the prop. Hard to put into words but as the level is allowed to pivot, it goes thru an angular change because the lower end of the level on the bottom of the blade is moving in an opposite "fore/aft" direction than the top of the level due to the twist of the prop. Also, your example of being 5 deg. might go without notice if working with a short level. I would venture to say someone could be up to 10 deg. off if they weren't paying attention and if the level might be allowed to tilt the other way on subsequent blades, there might result in a 20 deg. variance blade-to-blade. I realize that the result of this means only a few tenths of a degree variance which might not result in perceived vibration. Still, having a simple fixture takes all of the variance out of this and makes pitching a prop a quick and accurate procedure. Link to comment Share on other sites More sharing options...
chanik Posted October 1, 2011 Report Share Posted October 1, 2011 That could be, since the pitch of the blade is changing if the protractor twists. I did notice that if I move the prop blade a few degrees off from horizontal that is almost undetectable with the gauge. But getting the gauge mounted precisely perpendicular to the radial prop axis would be more crucial. Having the radial position on the blade off by 1/8" would also be about a 0.5% error which is also about what you would get being just 2Deg off with a twist. +-3Deg is about as well as I can eyeball a mounting so the laser method is much more accurate Link to comment Share on other sites More sharing options...
207WF Posted October 23, 2011 Report Share Posted October 23, 2011 Wow! I want the two of you to come to HHR and tweak my prop for me! WF Link to comment Share on other sites More sharing options...
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