jetdriven Posted May 21, 2012 Report Share Posted May 21, 2012 Quote: rbridges I saw that and was very surprised. He definitely did not like the new prop/engine combo. Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted May 21, 2012 Report Share Posted May 21, 2012 Should we have a LOP/ROP debate just to get all of the Mooney controversies in one thread? I *thought* I would get a bit of a performance boost over my OEM McCauley (square tip, narrow chord) that was used for only the 1977 J before being replaced with the 78+ version that I believe is a good bit better. I was disappointed to learn that my old prop wasn't all that bad, or the MT isn't much better from the performance standpoint. My dB measurements were inconclusive (could be the cheapy Radio Shack meter). The MT does look great, it does offer more ground clearance, it is much lighter, and it much smoother. The weight reduction was a primary characteristic for me (-12 lbs IIRC) since I want to add a turbo normalizer (+23 lbs). I believe the MT is optimized for a lower RPM than I would normally choose for moderate altitude LOP cruise, and that is why I'm slower. When I add the TN, this will be OK since I can run more MP to offset the lower RPM. Lycoming is doing themselves no favors charging such a premium and requiring a new prop at the same time for that IO-390 conversion. I'm still inclined to overhaul my current engine and save money for other upgrades or actually using the plane. Quote Link to comment Share on other sites More sharing options...
Flymu2 Posted May 22, 2012 Report Share Posted May 22, 2012 A data point: I compared the performance charts for the M20S standard configuration to the STC for the McCauley 3 blade conversion with 100 lb gross weight increase. The 3 blade is 5 kts faster in cruise and has slightly greater range and endurance. Climb is 30-50 fpm less and takeoff distance is slightly greater (probably attributable to the GW increase). The 3 blade is about 12 lbs heavier. Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 23, 2012 Report Share Posted May 23, 2012 Flymu, Check the HP rating on that aircraft. Many an eagle has been upgraded from two to three blades, but the HP seems to increase to 310 HP at the same time. Key words are Screamin' Eagle upgrade. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
John Pleisse Posted May 23, 2012 Report Share Posted May 23, 2012 Quote: jetdriven I saw that and was very surprised. He definitely did not like the new prop/engine combo. Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 23, 2012 Report Share Posted May 23, 2012 Props are expensive, three blades cost more than two. High tech materials cost more than aluminum. Weight and balance are effected. The benefits, most often, are too small compared to the price. If your plane needs a prop is one thing, or you are racing against Becca is another reason.... Overall, a knot costs a lot compared to the benefit... Improve HP: missile or rocket conversions are nice, increase prop rpm works within proven limits, turbo add-ons work Decrease drag: cowling, vent, wing roots, gear doors... What was the budget? -a- Quote Link to comment Share on other sites More sharing options...
SkyPilot Posted May 23, 2012 Author Report Share Posted May 23, 2012 Quote: carusoam Props are expensive, three blades cost more than two. High tech materials cost more than aluminum. Weight and balance are effected. The benefits, most often, are too small compared to the price. If your plane needs a prop is one thing, or you are racing against Becca is another reason.... Overall, a knot costs a lot compared to the benefit... Improve HP: missile or rocket conversions are nice, increase prop rpm works within proven limits, turbo add-ons work Decrease drag: cowling, vent, wing roots, gear doors... What was the budget? -a- Quote Link to comment Share on other sites More sharing options...
Flymu2 Posted May 23, 2012 Report Share Posted May 23, 2012 Quote: carusoam Flymu, Check the HP rating on that aircraft. Many an eagle has been upgraded from two to three blades, but the HP seems to increase to 310 HP at the same time. Key words are Screamin' Eagle upgrade. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 23, 2012 Report Share Posted May 23, 2012 When looking at upgrades for my M20C, I started to consider turbo normalization, then Missiles, then found the Ovation. It's a bit of a stretch, but you get a lot of upgrades this way... Try your best to identify your mission and how long that mission will last. I think I am on my last plane.... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
ionel Posted July 7, 2012 Report Share Posted July 7, 2012 Quote: SkyPilot Has anybody switched from a 3 blade prop to a 2 blade prop? Any speed increase noted? Quote Link to comment Share on other sites More sharing options...
jetdriven Posted July 7, 2012 Report Share Posted July 7, 2012 Consumer reports has a few articles about prop shops who "never met a prop that didn;t need overhaul". We have one in town that does that. They OH it for a large expense, and then 50 hours later its leaking, and then you have to buy a new one. Quote Link to comment Share on other sites More sharing options...
gregwatts Posted July 7, 2012 Report Share Posted July 7, 2012 Quote: SkyPilot Has anybody switched from a 3 blade prop to a 2 blade prop? Any speed increase noted? Quote Link to comment Share on other sites More sharing options...
Newmooneyguy Posted July 7, 2012 Report Share Posted July 7, 2012 There hasn't been much discussion of improved ground clearance with a 3 blade. I think that's a plus. Quote Link to comment Share on other sites More sharing options...
ionel Posted July 7, 2012 Report Share Posted July 7, 2012 Quote: gregwatts My experience was with a C model. Climbed better and then slowed down in cruise. I had a noticeable increase in vibration. At the time I was told that 3 blade props were cheaper than 2 blade because the jigs were set up for 3 and required a change if I wanted a 2 blade. I disliked the results of the 3 blade so much I sold the plane. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted July 7, 2012 Report Share Posted July 7, 2012 Quote: Newmooneyguy There hasn't been much discussion of improved ground clearance with a 3 blade. I think that's a plus. Quote Link to comment Share on other sites More sharing options...
Lood Posted July 8, 2012 Report Share Posted July 8, 2012 According to the Hartzell website, both their 2 balde and 3 blade props are 74" in diameter. So, no improvement in ground clearance then? Quote Link to comment Share on other sites More sharing options...
PilotDerek Posted July 8, 2012 Report Share Posted July 8, 2012 Only the mt prop is shorter. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted July 8, 2012 Report Share Posted July 8, 2012 No new discoveries in this thread. Some reading for you all. In short, a 3-blade looks cool but is a loser on anything but a TLS/Bravo or M20S Screamin' Eagle. Same with <300 HP Bonanza's. http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=2&threadid=4269 http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=3&threadid=4189 http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=2&threadid=2224 http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=2&threadid=906 http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=3&threadid=752 Quote Link to comment Share on other sites More sharing options...
WardHolbrook Posted July 8, 2012 Report Share Posted July 8, 2012 Quote: GeorgePerry Touché...IMHO low horsepower, (less than 240 hp) Mooney's should run a 2 blade prop. If the fundamental mission of low horsepower Mooneys is to provide fast, efficient travel then having a 3 blade prop is counter to that mission. Although 3 blade props climb better (+/- 200 ft/min increase M20J) it reduces cruise speed by a fair amout. Some reports put the 3 blade as up to 5 knots slower in cruise. The only exception to this is the MT composite which reportedly only loses a knot or two. Also 3 blade props are alot heavier and shifts the CG fwd, which also hurts top end speed. Higher horsepower (and typically heavier) Mooney's don't seem to suffer the same loss of top end speed and benefit from a 3 bladed prop. An umodded M20S with a three blade is a good example of this. Quote Link to comment Share on other sites More sharing options...
PTK Posted July 8, 2012 Report Share Posted July 8, 2012 Quote: WardHolbrook ...simply value the "ramp presence"... rate of climb? Quote Link to comment Share on other sites More sharing options...
ionel Posted July 8, 2012 Report Share Posted July 8, 2012 Quote: allsmiles I agree and echo these remarks! Personally, I find this notion of bolting on three blades somehow adds ramp appeal ridiculous. The Mooney, by definition, has ramp appeal! And as far as climb, it climbs just fine! Quote Link to comment Share on other sites More sharing options...
PTK Posted July 8, 2012 Report Share Posted July 8, 2012 Not sure I follow your logic! There is no "that implies" anything. In my opinion ramp appeal is in the eye of the beholder. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted July 8, 2012 Report Share Posted July 8, 2012 Quote: ionel I agree and echo these remarks! Personally, I find this notion of bolting on three blades somehow adds ramp appeal ridiculous. The Mooney, by definition, has ramp appeal! And as far as climb, it climbs just fine! Quote Link to comment Share on other sites More sharing options...
ionel Posted July 8, 2012 Report Share Posted July 8, 2012 Quote: jetdriven True, but then that implies that those with the McCauley 3 blade prop have MORE ramp appeal and can climb FASTER than fine while still achieving the same cruise speed and without the recurring gov/hub AD. Of course we are giving up the equivalent of ~2 gallons of fuel in useful load, but can make up for that with improved engine management. Quote Link to comment Share on other sites More sharing options...
Newmooneyguy Posted July 8, 2012 Report Share Posted July 8, 2012 This is the first time I heard that the 2 and 3 blade were the same diameter. I was told otherwise but I didn't measure it. Oh well. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.