Will.iam Posted January 22 Report Posted January 22 Well since my mccauley 2 bladed prop was starting to leak i decided to change from essentially a 1980’s design to a 2010 ish designed prop. I would loved if MT made a 2 blade scimitar prop for M20K aircraft but alas that’s just not the case. Since i am not FIKI certified and my 2 blade prop was labeled inop for prop heat anyway i elected to not install the MT heated blades either both as a weight savings and speed savings. By removing the heater ring and brushes as well as the mount i also gained 2 more pounds of weight loss. The total being 13 lbs off the nose. This really helped in the uptrim department as before i would be bumping up to full nose up trim now I’m half way between takeoff and full up. Cruise I’m below the takeoff box in the trim setting. Top end speed seems the same as before down low (2000-8000ft) i have not tested it yet higher as the winds were punishing high above 8000 on the way back home from kded to dfw. They were able to dynamically balance my prop to 0.082 ips which feels amazing. Before i hated to run at 2500rpm as it just felt better at 2300 on the 2 blade but now 2500 feels better that 2300 and is faster too. The biggest change for me is the takeoff and climbout. I genuinely feel the increase both in vvi and how quickly i get airborne which was my number 1 reason I chose to go with this prop over overhauling my 2 blade as my home airport only has a 2600ft runway and in the summer time it’s pushing the edge of my comfort zone for takeoffs. The prop noise is a different kind of noise. It is quieter than my 2 blade but not as much as i had heard from other people that have switched. The biggest change reduction is in the beats the 2 blade made that are now more like a buzz than beats if that makes since. At just above idle i hear the famous whispering the blades make but passed 1800 or so that either disappears or the engine noise drowns it out. Also changing rpm’s is now lightning quick i find using the twisting of the vernier prop knob much smoother than pushing the knob in because it’s just too sensitive otherwise. Now for the bad part that i loath and so wished they had a 2 blade option, taking the cowl off or on is a nightmare with the scimitar type blade they are much fatter at the base right where the cowl front edge needs to clear. I already have the first scratch marks on the back of the blades as the cowl is such a tight fit. The guys at the MT recommend wrapping the lower blades in wrapping plastic and using painter’s tape on the front end of the cowl to keep from making any more scratches hopefully that will help but changing my oil has now become a 2 person job for me where as before i could do it by myself. Anybody else have a better method please let me know. 5
Oscar Avalle Posted January 22 Report Posted January 22 24 minutes ago, Will.iam said: Well since my mccauley 2 bladed prop was starting to leak i decided to change from essentially a 1980’s design to a 2010 ish designed prop. I would loved if MT made a 2 blade scimitar prop for M20K aircraft but alas that’s just not the case. Since i am not FIKI certified and my 2 blade prop was labeled inop for prop heat anyway i elected to not install the MT heated blades either both as a weight savings and speed savings. By removing the heater ring and brushes as well as the mount i also gained 2 more pounds of weight loss. The total being 13 lbs off the nose. This really helped in the uptrim department as before i would be bumping up to full nose up trim now I’m half way between takeoff and full up. Cruise I’m below the takeoff box in the trim setting. Top end speed seems the same as before down low (2000-8000ft) i have not tested it yet higher as the winds were punishing high above 8000 on the way back home from kded to dfw. They were able to dynamically balance my prop to 0.082 ips which feels amazing. Before i hated to run at 2500rpm as it just felt better at 2300 on the 2 blade but now 2500 feels better that 2300 and is faster too. The biggest change for me is the takeoff and climbout. I genuinely feel the increase both in vvi and how quickly i get airborne which was my number 1 reason I chose to go with this prop over overhauling my 2 blade as my home airport only has a 2600ft runway and in the summer time it’s pushing the edge of my comfort zone for takeoffs. The prop noise is a different kind of noise. It is quieter than my 2 blade but not as much as i had heard from other people that have switched. The biggest change reduction is in the beats the 2 blade made that are now more like a buzz than beats if that makes since. At just above idle i hear the famous whispering the blades make but passed 1800 or so that either disappears or the engine noise drowns it out. Also changing rpm’s is now lightning quick i find using the twisting of the vernier prop knob much smoother than pushing the knob in because it’s just too sensitive otherwise. Now for the bad part that i loath and so wished they had a 2 blade option, taking the cowl off or on is a nightmare with the scimitar type blade they are much fatter at the base right where the cowl front edge needs to clear. I already have the first scratch marks on the back of the blades as the cowl is such a tight fit. The guys at the MT recommend wrapping the lower blades in wrapping plastic and using painter’s tape on the front end of the cowl to keep from making any more scratches hopefully that will help but changing my oil has now become a 2 person job for me where as before i could do it by myself. Anybody else have a better method please let me know. I have the same prop on my M20E and I fully agree with you PIREP. Overtime the rubber on the leading edge deteriorates but otherwise the prop ages well.
KSMooniac Posted January 22 Report Posted January 22 I'm still happy with mine since late 2010, even with a surprise overhaul and condemned hub last summer. I wish they had grease zerks... pay attention to any grease getting slung after the first 15-20 hours. I let mine go to long before a reseal attempt, and it ended up ruining my hub. Fortunately I was able to get a replacement quickly so the only pain was the big check. Otherwise, it is a great performer and much lighter and smoother than the other options, as well as offering 1' more ground clearance for the E/F/J. I don't know if that is the case for the K's. I suspect you should be able to dynamically balance it much better than 0.08 too... we got mine to 0.01 the last time I did it, and that is with a 4-cyl Lycoming! I took extra care during my engine overhaul to get everything balanced and flow-matched so I could get the smoothest possible 4-banger. A Continental 6 cyl should be able to get to that level too. I also suspect you can get some real optimal power settings with lower RPM (once you get it balanced better) and higher MP + LOP mixture setting. I believe MT optimized for lower RPM efficiency due to the noise sensitivity in Europe, and with a turbo, you have the flexibility to run there and not give up speed. I'm intrigued by the new Hartzell 2-blade composite prop, but so far have not seen any compelling data to think it is any better than the MT aside from cowl removal improvements.
Will.iam Posted January 22 Author Report Posted January 22 Unfortunately the Hartzell 2 blade is also not certified for the m20k. .the MT-12/188-53 is the same diameter as my mccauley at 74” so no ground increase for me. .01 would be impressive but i think most places stop after .1 no? i did an AI dive into performance calculations and through the power performance charts it reveled that 2575rpm as the optimal thrust of the prop achieving 92% with staying at or above 90% from 2600 to 2400 and that range shifting down 50rpm by 20,000ft which is the optimal altitude as well. Compared to my mccauley achieving 90% at 2500rpm and going down to 88% just 100 rpm lower and optimized alt of 18,000.
Will.iam Posted January 22 Author Report Posted January 22 Do you have the steel leading edge or nickel? I got the nickel version.
KSMooniac Posted January 22 Report Posted January 22 Mine is stainless steel...that is all they had in 2010. No complaints whatsoever aside from the bad paint I had to deal with under warranty back then.
MB65E Posted January 23 Report Posted January 23 Most stop at .03. .3 is a helicopter standard. Lol. .01 is really smooth. -Matt
1980Mooney Posted January 23 Report Posted January 23 Aren’t MT’s made in Germany? Is MT eating the current 10% Import Tax?
Will.iam Posted January 24 Author Report Posted January 24 I think so as the price was the same as a year ago. Was quite shocked by that and the fact no sales or labor state tax in Florida justified the fuel burn to and from dfw with extea savings to spare over having someone install it in texas. 1
KSMooniac Posted January 24 Report Posted January 24 Kansas has no sales tax on aviation parts too and it is quite helpful! (although I bought my J from an FBO and had to pay sales tax on it, unfortunately...maybe some day I'll break even)
1980Mooney Posted January 24 Report Posted January 24 7 minutes ago, KSMooniac said: Kansas has no sales tax on aviation parts too and it is quite helpful! (although I bought my J from an FBO and had to pay sales tax on it, unfortunately...maybe some day I'll break even) General Aviation…”break even”?! 1
KSMooniac Posted January 24 Report Posted January 24 30 minutes ago, 1980Mooney said: General Aviation…”break even”?! which is why I never add it all up... 1 1
Will.iam Posted January 25 Author Report Posted January 25 4 hours ago, 1980Mooney said: General Aviation…”break even”?! Sssssh let me keep dreaming.
Will.iam Posted February 13 Author Report Posted February 13 New Pirep on seat of the pants takeoff performance. In the past with our 50 ft drop in elevation at about midway down the runway at max gross takeoff weight my abort decision was visually easy to acquire as I needed to be airborne before the aircraft reached the bottom of the hill and with temperature differences sometimes I would be airborne as I was coming down the hill. Well today with max gross weight takeoff I was airborne before I even started down the hill and climbing at a full 1000ft per min after airborne made for a much bigger performance cushion than what I had in the past. 2
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