joepilot Posted October 6, 2015 Report Posted October 6, 2015 I've read some other reports on the Top Prop, but here's mine, for anyone who cares. I have a '94 J ("adopted" from Gary H) which had the McCauley since new. I have only flown it a few hours since install, but here's my opinion so far: TO & climb performance seems about the same. MAY be getting a couple knots extra in cruise. Did 2 four-way GPS tracks, but none were in great conditions. The Hartzell is 9 pounds heavier, but what's MUCH worse is I'm noticing a LOT more vibration in both climb & cruise. The old McCauley set up was silky smooth. Center post mounted compass shakes a lot in climb now. I've had it dynamically balanced, then rechecked by another mech with a different machine. Balance is perfect; at 0. Printout confirmed. Motor mounts in good shape, but have they "learned" the old prop? Anybody else ever see this? I've heard a/c manufacturers try to find the smoothest prop/motor combination & engineer accordingly, which may explain why an STC'd piece of equipment is not always as good. The only really good news so far is that the Hartzell was almost $3000 cheaper than the McCauley. Oh, and my new/OH ignition system now gives me 1/2 blade starts, even hot, & motor running cool, and running VERY well & balanced LOP! Oh well, pay your price & take your chances. -Joe Quote
Browncbr1 Posted October 7, 2015 Report Posted October 7, 2015 The top prop has torsional vibration restrictions. You can't run it between 2350-2500rpm when over 24" MAP. Below 24", there is no restriction, but it does run smoother at 2500rpm. Mine is balanced to 0.04 and seems ok. I noticed it was smoother when I recently installed new mags too. Quote
Bob_Belville Posted October 7, 2015 Report Posted October 7, 2015 I cruise with mine (Scimitar/IO360-A1A) at either 2550 or 2350 because of the RPM restriction, even when I'm pulling <24". The engine/prop seems to like 2550 better though it is smooth at either speed. I like to run full throttle and RAM air open so even at 9000' yesterday I was running @ 70% power (22" MAP) until I pulled prop back to 2350. At 2350 I was indicating ~65% power and felt comfortable pulling mixture to ~ 9 gph. 5 kts slower but 20%+ less FF. (FWIW, rear cylinders CHT were ~335 and front were ~370.) Quote
joepilot Posted October 7, 2015 Author Report Posted October 7, 2015 Thanks. I don't have the RPM restriction because I have a J model. Hartzell wants to see my dynamic balance printout. Also could be just the way the new prop's airflow is around the airframe. This could be worse than chasing down electrical issues! Here's a vid of my compass shaking during climb. The frequency is actually a bit higher than the iPhone recorded. Parts are gonna wear out... IMG_4260.MOV Quote
carusoam Posted October 7, 2015 Report Posted October 7, 2015 Unable on that video. Using iPad... just me? -a- Quote
Bennett Posted October 7, 2015 Report Posted October 7, 2015 I generally run my Top Prop J at 2550, ram air open (LoPresti cowl), full throttle, and about 75% HP at 7,500'. I've had the prop dynamically balanced twice- as good as the gauges will show, and there is no noticeable vibration. 1 Quote
Bob_Belville Posted October 7, 2015 Report Posted October 7, 2015 I generally run my Top Prop J at 2550, ram air open (LoPresti cowl), full throttle, and about 75% HP at 7,500'. I've had the prop dynamically balanced twice- as good as the gauges will show, and there is no noticeable vibration. Hi Bennett, your J has better cooling than my E, particularly with the LoPresti. What FF do you use @ 75%? 11.5? 75+ ROP? Quote
fantom Posted October 7, 2015 Report Posted October 7, 2015 Beautiful plane, Joe! Trust you kept the old McCauley ;-) Quote
joepilot Posted October 7, 2015 Author Report Posted October 7, 2015 Beautiful plane, Joe! Trust you kept the old McCauley ;-) Thanks! Haha. Working on getting the McCauley back, but I don't think screwing that one back on is an option. Ill try try the vid again, but doesn't seem to load from my phone. Quote
Bennett Posted October 7, 2015 Report Posted October 7, 2015 Hi Bennett, your J has better cooling than my E, particularly with the LoPresti. What FF do you use @ 75%? 11.5? 75+ ROP? I generally see fuel flows at about 11.8 to 12.2 depending on outside air temp and altitude. My "sweet spot" is between 8,000' and 10,000'. The LoPresti ram air provides about 1 to 1.4" increases in MP. Well designed ram air mechanism. I keep CHT temps below 370 degrees (hottest cylinder) if I crack the cowl flaps a bit I can keep CHTs under 350 degrees. 1 Quote
Bob_Belville Posted October 7, 2015 Report Posted October 7, 2015 I generally see fuel flows at about 11.8 to 12.2 depending on outside air temp and altitude. My "sweet spot" is between 8,000' and 10,000'. The LoPresti ram air provides about 1 to 1.4" increases in MP. Well designed ram air mechanism. I keep CHT temps below 370 degrees (hottest cylinder) if I crack the cowl flaps a bit I can keep CHTs under 350 degrees. Great, I can run there (except CHTs will be a little higher but acceptable) if I'm in a hurry or if I'm taking a panel pic for Marauder. My old RAM air is worth 1". I do have PowerFlow exhaust) I was @ 22" MAP @ 9000 PA, 9300 GPS altitude, didn't calculate DA. You're doing 160kts+, TAS? Quote
OR75 Posted October 7, 2015 Report Posted October 7, 2015 i am ready to bet that when you shut down , your prop always come to a stop like it is on your picture ... At 6-12 o'clock Quote
joepilot Posted October 7, 2015 Author Report Posted October 7, 2015 i am ready to bet that when you shut down , your prop always come to a stop like it is on your picture ... At 6-12 o'clock With the new prop, more times than not, I believe. But at least more often than the McCauley did. What are you thinking?? IMG_4260.MOV Quote
Bennett Posted October 8, 2015 Report Posted October 8, 2015 Great, I can run there (except CHTs will be a little higher but acceptable) if I'm in a hurry or if I'm taking a panel pic for Marauder. My old RAM air is worth 1". I do have PowerFlow exhaust) I was @ 22" MAP @ 9000 PA, 9300 GPS altitude, didn't calculate DA.You're doing 160kts+, TAS? I also have the PowerFlow exhaust system, and the combination of these mods allows for normal cruise at well above 160 KTAS. Every so often I run the prop at 2700 RPM, close everything, including the vents, and richen the mixture a bit more to keep everything cool, full throttle, and I can just touch 170 KTAS in level flight. My old 261 conversion's POH said running at 83% power was OK, and I'm used to running high power settings. The JPI 830 is a great tool for watching the engine parameters. Lately I have been adding too many antennas. I buried almost all the antennas in the wingtips and belly pan on my 261, but I was a fanatic about speed then. Then came the Rocket conversion, and then it was over. The J is "good enough" for me for the type of flying I am doing today. 2 Quote
Bob_Belville Posted October 8, 2015 Report Posted October 8, 2015 My prop always stops @ 10/4 (as viewed from in front). I've forgotten what the reason is... Quote
Andy95W Posted October 8, 2015 Report Posted October 8, 2015 My prop always stops @ 10/4 (as viewed from in front). I've forgotten what the reason is... For a 4-cylinder Lycoming and 2-blade Hartzell it means that it was put together correctly. Quote
jetdriven Posted October 8, 2015 Report Posted October 8, 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. Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 2015 For a 4-cylinder Lycoming and 2-blade Hartzell it means that it was put together correctly. So, 12/6, 10/4 stoppage. Any mechanical rationale or tell tails behind this statistical phenomenon? As a non-mechanic, dumb pilot, seems like a 1 in 4 coincidence on a 4 cylinder 4 stroke. (But good odds vs roulette!) Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 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. I helped with my install, and it seems with the flange "holes", there was only 2 options of the prop install position. No? Quote
Andy95W Posted October 8, 2015 Report Posted October 8, 2015 I helped with my install, and it seems with the flange "holes", there was only 2 options of the prop install position. No? I was flippantly speaking in generalities that really apply mostly to the more "vintage" Mooneys with a stock engine/propeller combination. Not sure what the Top Prop does to change that. They may have wanted the compression and combustion impulses on the prop at a different angle than the original. Depending on compression health and heat of the engine at shutdown, I would expect anything from about 9:30-11:30 for a vintage, stock airplane. Quote
jetdriven Posted October 8, 2015 Report Posted October 8, 2015 Iirc thise those bushings can be driven from the prop flange and the recessed holes in the prop hub might have more than one variation. I am pretty sure the prop and the crank throws are inline on an A3B6 (d) engine. I.E., when one piston on each side is at TDC, the prop is horizontal. Take a look. Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 2015 Ok, thanks! Wilco. Although I think my 2nd mech checking the dynamic balance checked this. Quote
OR75 Posted October 8, 2015 Report Posted October 8, 2015 With the -A3B6D , the top prop cap be installed only two options. You can turn it a 180 degrees and it may make a difference. It did with my install even thought the prop was tested on the bench and found to be perfectly balanced. It reduced the vibrations in a certain rpm range. Do a search or "Google" 1/2 order vibrations. Quote
joepilot Posted October 8, 2015 Author Report Posted October 8, 2015 (edited) With the -A3B6D , the top prop cap be installed only two options. You can turn it a 180 degrees and it may make a difference. It did with my install even thought the prop was tested on the bench and found to be perfectly balanced. It reduced the vibrations in a certain rpm range. Do a search or "Google" 1/2 order vibrations. That's good information (and a cheap troubleshoot). Thank you! Detailed link: http://www.propbalancing.com/Vibe Analysis.htm Edited October 8, 2015 by joepilot link added Quote
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