OR75 Posted October 8, 2015 Report Posted October 8, 2015 I installed the top prop about two years ago. Good looking prop . Very smooth operation on the ground , the dynamic balancing may have helped but to be honest it was already very smooth on the ground even before the dynamic balancing . Take off roll: the top prop seems to me less crisp than the McCauley. It takes it a little more time to get going and become very efficient when the plane is moving. As a result I apply power a little more progressively At high RPM in climb It is also very smooth. At low RPM , it is very smooth ( unlike the previous McCauley that had a yellow arc - I really did not need to look at the tach to know if i was in it !) vibration occur when i throttle back in the 2200-2450 RPM range. Less vibration after I re-indexed the prop 180. but I have no idea why since the prop was found to be perfectly balanced on the bench ! I used to cruise at 23in 2300RPM with the McCauley.. Now I tend to be at 23in 2450-2500RPM i would prefer to be at 2300 RPM (in part to reduce noise - but my ears tell me the the McCauley at 2300RPM had the same sound level as the top prop at 2500RPM From on my research .... As certified ... Not many options. Making the engine lighter may help (lightweight starter helped -plus I wanted a faster starter - I am not sure the PP alternator is lighter that the prestolite , other idea ? ) Personally I believe having a A1B3 can help ( re-indexing) but I am not sure the prop is approved with that engine model at overhaul, I am planning to go to a non D engine and the 20 degrees (vs 25 degrees) timing may help also. Hope this helps ... Quote
jetdriven Posted October 8, 2015 Report Posted October 8, 2015 (edited) All the 20 degrees timing does is slow your plane down 3-5 knots and runs 20 degrees cooler. Climb rate and LOP performance is also similarly affected. There is no difference in vibration Edited October 8, 2015 by jetdriven Quote
OR75 Posted October 8, 2015 Report Posted October 8, 2015 Timing may affect 1/2 order vibrations Quote
jetdriven Posted October 8, 2015 Report Posted October 8, 2015 (edited) Having ran two different engines at 20, 23, and 25 degrees, there is no difference. All the cylinders get retarded or advanced by the same amount what 20 degrees does is reduce power. Unless the peak power is at 23 degrees and both 20 and 25 degrees both produce the same. But I doubt that Edited October 8, 2015 by jetdriven Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 2015 Realized I need a link to post a vid. Hope this works. The vibration may just be a different frequency than the McCauley had, but it definitely appears, and feels, to shake things more. This vid is taken in climb. 2700rpm, full throttle, low altitude. As mentioned, vid didn't quite catch the higher frequency of the compass vibrating, but you get the idea. Shakes a lot more than I noticed the McCauley. 65-70%hp 2500rpm cruise reduces vibration, but not as smooth as old prop. Quote
N601RX Posted October 8, 2015 Report Posted October 8, 2015 Have you checked the tracking of the blade Tips? Unlikely it is off with a new prop, but never know. Also is different clocking of the prop on the crank possible on your engine prop combo? Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 2015 Thanks! Yes, checked the blade track & blade angles. Both perfect. Spinner appears motionless from side view when running. I believe there's one other position the prop can be mounted on the flange. May try it; couple hours of labor vs more drastic (expensive) actions. Quote
carusoam Posted October 8, 2015 Report Posted October 8, 2015 (edited) Have you by chance tightened the screws holding the compass in place recently? My C's compass was doing that vibration. The tighter the screws the worse the vibration became. It must be located in the middle of the tube where the vibration is at a maximum amplitude. Of course, this doesn't solve the original problem. But, the compass shouldn't vibrate like that either. It would probably take a spongy piece of rubber between the compass and the tube with lightly tightened hardware to absorb the shake... Are you feeling or measuring the vibration in other ways as well? Best regards, -a- Edited October 9, 2015 by carusoam Quote
jetdriven Posted October 9, 2015 Report Posted October 9, 2015 Our compass does something similar at 2700 rpm. A piece of foam between the compass and the glare shield took care of that Quote
joepilot Posted October 17, 2015 Author Report Posted October 17, 2015 Had a 40 year professional aeronautical engineer run a diagnosis on my vibration issue today. Vibration levels are changing at fixed RPM's & he believes there's a mechanical, infant mortality issue inside the hub. Looks like I could be headed down a long road... Anyone dealt with Hartzell on warranty issues? Quote
joepilot Posted October 18, 2015 Author Report Posted October 18, 2015 Damn Joe.... I know... Been a frustrating & expensive first year. ADS-B (my option), then volt reg/alternator, #2 nav-com dead (again), new ignition system, now brand new prop with issues. Hope it gets better. Grounded again, as I choose not to fly a single engine after a diagnosis of a problem with the prop hub. Quote
garytex Posted October 18, 2015 Report Posted October 18, 2015 My J stops at 11:00 and 5:00 when viewed from the front. If the prop is clocked wrong it can do what the OP is describing. In fact the A3B6 is simply the A1B6 with the prop clocked one hole off. That was my first thought, to check that the prop is clocked properly. I have bought 3 A?C in my life, all 3 were clocked wrong, and my mechanic continues to tell me about improperly clocked props that come in to his shop pretty regularly. Quote
joepilot Posted October 18, 2015 Author Report Posted October 18, 2015 There's a Lycoming Service Instruction (1304?) that addresses this, but is not applicable to my plane. Quote
RobertGary1 Posted October 18, 2015 Report Posted October 18, 2015 That was my first thought, to check that the prop is clocked properly. I have bought 3 A?C in my life, all 3 were clocked wrong, and my mechanic continues to tell me about improperly clocked props that come in to his shop pretty regularly. how does this happen? At least on my A3B6 the prop will only go on one way. My prop always stops at 12:00. -Robert Quote
Cyril Gibb Posted October 18, 2015 Report Posted October 18, 2015 I have been doing some reading re: vibration. Mooney SB M20-206 talks about reclocking the prop to reduce vibration. Additionally, there is a bunch of recommendations from other type specific sites about reclocking. Even the Skyranch recommendation is consistent with the others. It seems that the current prop clocking was traditional based on the need to hand prop, but doesn't optimise (non-US spelling) the orientation that minimizes vibration. Apparently, orienting the prop parallel to the #1 crankthrow should be best. Has anyone done the M20-206 Service Bulletin ? Did it make any difference ? Has anyone done the recommended prop reclocking to any other engine model with success, or not ? Quote
RobertGary1 Posted October 18, 2015 Report Posted October 18, 2015 So the SB seems to infer that the A1 series can be indexed as an A3 by changing the bushings. Those of us with the A3 already I don't think can change the clocking. The poster who said his A&P sees a lot of props indexed wrong probably either means that they haven't enjoyed the benefit of the SB or he saw those modified by the SB and didn't realize it existed so he set it back to factory. -Robert Quote
joepilot Posted October 18, 2015 Author Report Posted October 18, 2015 So the SB seems to infer that the A1 series can be indexed as an A3 by changing the bushings. Those of us with the A3 already I don't think can change the clocking. This is the Mooney SB version of the Lycoming SI 1304 I referenced earlier. I agree, I don't think these Bulletins apply if you have a factory A3; should already be set up correctly. In my case, plane was silky smooth with the McCauley and is NOT with the Hartzell. So, gotta be a prop issue, whether mechanical or a compatability issue. Quote
Cody Stallings Posted October 18, 2015 Report Posted October 18, 2015 What is an infant mortality issue? I must ask, has anyone greesed the propeller after it was run for the first time? offten overlooked, greese plays a big role in the balance of a propeller. Quote
joepilot Posted October 18, 2015 Author Report Posted October 18, 2015 What is an infant mortality issue? I must ask, has anyone greesed the propeller after it was run for the first time? offten overlooked, greese plays a big role in the balance of a propeller. He thinks there's a mechanical issue with the new prop. Here's about infant mortality: https://en.m.wikipedia.org/wiki/Bathtub_curve No one greased after first run. Not listed in the Prop Manual as recommended action. Had vibration issue on first flight. But thanks, I'll ask. Quote
RobertGary1 Posted October 18, 2015 Report Posted October 18, 2015 (edited) When I installed my prop the prop shop recommended lubing after 5 hours because the lube will move around. Edited October 18, 2015 by RobertGary1 Quote
jetdriven Posted October 18, 2015 Report Posted October 18, 2015 This is the Mooney SB version of the Lycoming SI 1304 I referenced earlier. I agree, I don't think these Bulletins apply if you have a factory A3; should already be set up correctly. In my case, plane was silky smooth with the McCauley and is NOT with the Hartzell. So, gotta be a prop issue, whether mechanical or a compatability issue. verify the prop blades are parallel with the crank throws. With #1 at TDC the prop should be horizontal. Don't rely on the prop bushings that fit into the prop, actually go out and mechanically verify it. I had a friend who prematurely overhauled his engine because #4 was running hot and the mechanic decided the cam on that cylinder was bad. The overhaul shop called and the entire engine was fine inside, but they already tore it down. The overhauled engine was running very hot on #4 again. Turns out it wa she new slick mags that the mechanic said were fine. Nobody ever bothered to verify the internal magneto timing Quote
testwest Posted October 18, 2015 Report Posted October 18, 2015 (edited) Joe, we have a 77 M20J as shown in our sig below. Our prop stops at 6-12 like the picture, and it is very smooth. One item to check that has not been mentioned is the condition of your crankshaft counterweights. If they have been detuned, it could cause the issues you are seeing. John Schwaner's Sky Ranch Engineering Manual has a marvelous write up on this and referrals to Lycoming service instructions to troubleshoot the problem. Here is a link to a page excerpt from this fine book regarding detuned counterweights: https://books.google.com/books?id=JEXnFqVTqJQC&pg=PA426&lpg=PA426&dq=crankshaft+counterweight+detuning&source=bl&ots=dRBcJYb83H&sig=iKac0xO4uIpTvxjyhZV2No8-vno&hl=en&sa=X&ved=0CEMQ6AEwBGoVChMIuPz0u5rNyAIVCMxjCh26hQiX#v=onepage&q=crankshaft counterweight detuning&f=false It is entirely possible that the counterweights could be detuned and still show no symptoms on the previous prop, but be apparent with the new prop due to different resonance characteristics of the new rotating mass, in both magnitude and phase angle. Attached is a copy of Lycoming SI 1012G. Everything you ever wanted to know about counterweights. Good luck! And please let us know what you find. Counterweights and Rollers on Engine Models.pdf Edited October 19, 2015 by testwest Quote
joepilot Posted October 19, 2015 Author Report Posted October 19, 2015 Testwest, Thank you very much for the info & links! I'm trying to absorb as much as I can on this subject because I'm not happy with my situation, and I think I know what I'm going to hear from Hartzell... Quote
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