Hey barnstormer. I want to but your 86" two blade once you have made the switch!!!

Phil,

Thanks for the quick response. I'm totally sold on the MT blade technology and the weight, the only thing that hangs me up is the RPM. It's not a "tip" speed thing for me; I know the shorter blades at 2850 would be a big improvement over the other blades in that department. My hang up is the engine is rated for 300 at 2850. the net result of the 3 blade MT at 2700 probably is better performance over the other props at 2850. But that's a thrust issue. I have to think that with a good blade like that, not running at 2850 is leaving something on the table for takeoff. Just my opinion.

Thanks again,
Bill

Maybe and maybe not. The shock waves associated with breaking the sound barrier create a lot of drag. Transonics can happen at much lower M numbers than a calculated M 1.0 tip speed as well.

While your engine may make more power at 2850, the extra power may or may not be eaten up by the extra drag on the prop. Heck, you may even make less thrust than at a lower RPM due to the excess drag!

bigrenna wrote:I know you had a hell of a time with your light weight starter, but I might chalk that up to the Hartzell. I've got 250 hard hrs of short hops (lots of starts) with no issues using the Skytec/MT combo. No way Im putting that heavy starter back on if I can help it.

Greg, you are either one of the lucky ones, or my friends are some of the unlucky ones. And yep, the Harztell M-Drive in junk.

PAMR MX wrote:Hey barnstormer. I want to but your 86" two blade once you have made the switch!!!

I’ll let you know once the change has been made, probably in July.

fiftynineSC wrote:Phil,

Thanks for the quick response. I'm totally sold on the MT blade technology and the weight, the only thing that hangs me up is the RPM. It's not a "tip" speed thing for me; I know the shorter blades at 2850 would be a big improvement over the other blades in that department. My hang up is the engine is rated for 300 at 2850. the net result of the 3 blade MT at 2700 probably is better performance over the other props at 2850. But that's a thrust issue. I have to think that with a good blade like that, not running at 2850 is leaving something on the table for takeoff. Just my opinion.

Thanks again,
Bill

I hear ya Bill, that’s what has kept me from making the change. But I suspect CamTom12 might be on to something. As long as MT is willing to take it back if I’m not satisfied, that’s a pretty good reason to go for it. We shall see.

FWIW my experience with that same prop on a 280hp +/- C180 is that although I have the 2700 rpm redline, under most circumstances my T/O performance is best dialed back to 2600-2650. Under those circumstances it is noticeable and repeatable.

Take care, Rob

Look, folks.....the bottom line on propeller performance is THRUST, not horsepower. As Cam noted, horsepower is certainly a factor, but it's really easy on these engines to convert that extra horsepower to noise. Horsepower is essentially a representation of energy. Noise (sound) is also a form of energy.

What you want to do is convert horsepower to thrust, not to noise, and as Cam pointed out, those prop tips don't have to be very close to mach to convert a fair bit of horsepower to noise.

For a number of years, I operated a Beaver with a Hamilton Standard 2D-30 propeller. The Beaver standard 2D-30 blade is a -12, meaning 12 inches are cut from the basic stock blades to achieve the proper blade length for that engine/airframe. My airplane's propeller had -6 blades......a VERY long propeller.

I was really proud of that prop....I mean it was looooong, and man, did it make some noise on takeoff.... In fact, so much so that during a presentation at the Lussac Library in Anchorage fifteen years later, I put a picture of that airplane up on the screen and a guy in the back of the audience hollered "So you were the SOB that woke me up at 5:00 AM twice a week that summer".

The problem with that long prop was that it was hard to keep it out of the water on floats. So, eventually, the blades got to limits, and our maintenance folks decided to make the thing legal for a change......meaning putting legal blades on that prop.

I was devastated. The new blades were AG-100 blades....big paddle blades, but.....short .

Actually, I was devastated right up till I made the first heavy takeoff from water......then.... Holy shit, as they say..... That prop pulled like a tugboat, compared to that long thin blade.

Noisy props are not necessarily all they're cracked up to be.

Again, it's THRUST that's the goal, and horsepower is just one factor in the equation that results in that solution.

MTV

^^ This.

Cant find it right now, but somewhere buried on this site is Aktahoe's pull tests with his various props, including the MT. If I recall correctly, the MT made the most thrust at slower RPM's. (2500 as opposed to 2700 or something like that)

So I spoke with Larry Schlasinger, at Flight Resource, on Friday about the causes for starter adapter failures that occur to some when changing to a lightweight prop, in this case the MT prop.

According to Larry the primary culprits are: the new style starter adapter; the lightweight starters; a battery that is in less then ideal condition; and a magneto that is improperly timed or not set up correctly.

Or putting it another way, what Larry believes is the correct setup to eliminate starter adapter failure is: the old style starter adapter, the energizer starter, a battery that is in good condition, and a properly set up and adjusted magneto.

He did add that folks that set their mag timing to 25 degrees, instead of the factory setting of 22 degrees, run the risk of breaking the adapter because the impulse coupling is now firing before TDC instead of after TDC, which could cause the propellor to spin backwards damaging or breaking the starter drive.

McCauley has not yet responded to my inquiry.

mtv wrote:during a presentation at the Lussac Library in Anchorage

Mike, I don't know how many of those presentations you did, but I went to one in 2001 that made me rethink the way I fly. I still talk about it to this day, and in fact thought about it today before I read this post. Thank you! You made a difference.

slowmover wrote:

mtv wrote:during a presentation at the Lussac Library in Anchorage

Mike, I don't know how many of those presentations you did, but I went to one in 2001 that made me rethink the way I fly. I still talk about it to this day, and in fact thought about it today before I read this post. Thank you! You made a difference.

Slowmover, I did a few there over the years. Thanks for the comment....it's always good to know you helped somewhere along the line.

MTV

I know that this is going to be an extremely unpopular view on a sight where the MT prop is considered the greatest thing since sliced bread but I find it interesting that the people selling the light weight prop fail to mention that one of the problems is the reduced cranking inertia of the light weight prop compared to the weight the props which were available when the engineers designed the engine. When the engine was designed and the retard of the impulse coupling was determined the engineers took into consideration the available inertia in the prop (read flywheel) to continue rotation of the crankshaft in the correct direction when the first cylinder fires. An engine with a light weight prop requires the starter and thus starter drive to contribute a greater share of that force, possibly more than it is designed for resulting in failure of the starter drive or the starter. I can not say that the sellers of light weight props are aware of this factor, but it is interesting that they say that reducing the timing from 25 to 22 degrees, which has the same effect as increasing the impulse coupling retard by 3 degrees reduces the chance of kickback (reversing of crankshaft direction of rotation). These engines have started fine for decades with inaccurate timing and weak batteries with the old heavy props, and I personally would not want to be dependent on a strong battery and perfect timing when in the back country.

Tim

Tim, that is my thoughts exactly. I've never put it in writing because I'm not good enough with words to defend my position.

Hmmm, well, I have hand propped several aircraft equipped with "lightweight" (read MT) props. Never a problem, though wearing a glove is a good idea, since the trailing edge of those blades is sharp.

But, inertia.....not an issue for hand propping.

Learning to start your engine also helps.....and hand propping occasionally will guarantee that you learn that process.

FWIW

MTV

Barnstormer wrote:....He did add that folks that set their mag timing to 25 degrees, instead of the factory setting of 22 degrees, run the risk of breaking the adapter because the impulse coupling is now firing before TDC instead of after TDC, which could cause the propellor to spin backwards damaging or breaking the starter drive.....

I know a couple guys that bump the timing up to boost the power in their 150hp 320 Lyc's, figuring it's OK cuz they run 100LL instead of 80/87. Never thought about it changing when the impulses fire. Thanks for mentioned this aspect of things.

I do find it interesting that similar engines or different dash numbers of the same basic engine spec out such widely varying timing. For a quick example, check out TCDS E-273 for the Continental O-470. Timing varies from 20* BTDC to 26*. The A & J engines are pretty similar, with the main difference as I understand it being heavier cyls on the J, but the A times at 26 and the J at 20. The K L R & S all time at 22.

bat443 wrote:I know that this is going to be an extremely unpopular view on a sight where the MT prop is considered the greatest thing since sliced bread but I find it interesting that the people selling the light weight prop fail to mention that one of the problems is the reduced cranking inertia of the light weight prop compared to the weight the props which were available when the engineers designed the engine. When the engine was designed and the retard of the impulse coupling was determined the engineers took into consideration the available inertia in the prop (read flywheel) to continue rotation of the crankshaft in the correct direction when the first cylinder fires. An engine with a light weight prop requires the starter and thus starter drive to contribute a greater share of that force, possibly more than it is designed for resulting in failure of the starter drive or the starter. I can not say that the sellers of light weight props are aware of this factor, but it is interesting that they say that reducing the timing from 25 to 22 degrees, which has the same effect as increasing the impulse coupling retard by 3 degrees reduces the chance of kickback (reversing of crankshaft direction of rotation). These engines have started fine for decades with inaccurate timing and weak batteries with the old heavy props, and I personally would not want to be dependent on a strong battery and perfect timing when in the back country.

Tim

I'm not here too poo poo the MT either but I think the "greatest thing since sliced bread" has another side as well. I know of a couple incidents where they have completely came apart (yes they hit stuff -- but a Mac would have made salad of that stuff) and one that had extremely low hrs and had to go to factory for a rock ding.

Anyway, I just re- "war-gamed" it personally and purchased another Mac. Even with Mac's prices increasing….
There isn't much I'd like more than to drop that weight off the nose (and who doesn't like new stuff) but the lack of resilience is something I couldn't personally sacrifice. Now if I were on floats, I think thats a different conversation entirely.

I appreciate new technology and those who develop it. Certainly! Maybe the MT is the answer for a lot of guys….but there are always negatives and this one is substantial for some of us. Just something to think about in the "best thing" talk.
Maybe not a big deal for "you" but it is for many of us here.
I'd imagine thats why they aren't hanging on a lot of wagons here.
Cheers,
KA

I've been hand propping the new 2-blade MT on cold starts as the starter pulls just fine the first two blades but will hang on the third sometimes. Usually fires first blade hand propping, but I prime and pull 3-4 blades through and load the system (guess I could do that prior to using the starter too). Once warm fires up great with the starter, no problem.

I have now overhauled the bendix mags, overhauled starter drive, double checked the timing (24 deg), and am gonna swap my energizer starter with another spare I keep in the hangar tomorrow. It is possible that this starter is wearing out, unknown hours on it. Battery is new so there is nothing else to replace after that.

Starting to really like the MT prop. As far as inertia being the culprit I am somewhat skeptical. I lost 8 pounds total (certified scales), including spinner n backplate etc., over the C204 82" that was removed, so we are not talking a tremendous amount of weight. The three blade MT is as heavy/heavier than the McCauley I removed, so that would be strange for there to be any issues with the 3-blade MT if inertia is the problem. Are there abnormal kickback issues with the 3-blade MT on Continentals? Seems like almost everyone I've heard having this issue had the 2-blade?

As far as starter drives, after talking to many people, I went with Niagara's advice and opted for the new style again. The new style will break clean almost every time and thus I can hand prop as long as necessary should this happen again. The old style can bind and cause major damage to the motor etc. Guess I get to be the Guinea Pig as so many pilots say the classic style with the energizer starter is the way to go. Not one IA/A&P I consulted with nor the Niagara folks agreed with that, they all said new style starter drive period...

I wanted to upgrade the prop on my old C180. I'm pretty much old school but just for grins requested a quote on an MT from John at Flight Resource last march. He quoted a 2-blade scimitar 83" prop, including Kevlar spinner & STC, at $12,950 plus crate & freight. Wow! I'm sure it's an awesome prop but way above my pay grade. I got a quote from a local prop shop for a new 88" Mac (which my existing spinner will fit) for around $8200. Still pretty spendy....I ended up buying a used 88" Mac from the friend of a friend for a grand, which I'm now having overhauled & converted to oil-filled) for another 4K. So I'll be good to go for a long time for around $5K.

Happy Days Are Here Again!

Just got word from my A&P/IA (pictures sent by him) that the wagon is ready to fly again. As a recap I had him pull the tail and replace every single bushing, bearing, nut and bolt, at the suggestion of Willie Stene. Thanks Willie for helping me spend my money.

The old crappy MX radios are gone. And the Apollo GPS is out. Replaced by a Garmin GTN650 and a Garmin CDI with Glideslope. The Annunciator still has to be installed but that will have to wait until we are back from San Diego seeing our daughter, son-in-law, and granddaughter off to Japan for their last deployment before retirement.



Also need to pull the second, no longer hooked to anything, CDI and replace it with a blank plate for now. Gonna placard it Inop in the morning before test flying the plane.

Also got the starter adapter accessory drive oil seal replaced. And got the "annoying passenger stay-in-the-back" net installed.

Barnstormer wrote: And got the "annoying passenger stay-in-the-back" net installed.

Bah. I'm telling you, man - zombies will reach right through that thing and eat your brains...

CapnMike wrote:Bah. I'm telling you, man - zombies will reach right through that thing and eat your brains...

Hmmm, hadn't considered that.

Found out we don't need to install the annunciator as the GTN 650 is close enough to my line of sight. Hopefully I can return it and get my money back.

Test flew her yesterday and brought her home. Couple of squawks to work through.

1. Intercom volume is too low.
2. Autopilot turn rate is half what it should be.

I suspect these are related to now interfacing with the GTN. Hopefully not a big deal to adjust.

Nice to have a touchscreen GPS that is approach certified (now I just need to finish my IFR training), but I had to smile when I was reminded it doesn't display Wx until I hook it up to something like the GDL 39, or the Baron Mobile Link.

The iPad/iPad-Mini with Foreflight or Garmin Pilot is the best technology by far.

Sure is nice to be flying her again.

Now I need to find a paint shop so I can get the WingX and Sportsman painted.