What’s the difference in these two MT props

[rv6ehguy]

Vans Aircraft and MT recommend the MTV-9-B/183-50a for my
AeroSport IO-375 195hp engine. I have an opportunity to purchase
a low time MTV-9-B/200-52.
Apart from the diameters of the props what’s the difference between
the two? I know the MTV-9-B/200-52 is 78 inches in diameter and MT’s
specs list the minimum diameter as 76 inches which is too big for an RV6A.
Or is it? What is the required distance between the prop tips and the ground?
I have installed the new rubber puck type landing gear on my RV6A so the
engine rides a little higher than a RV6A with the standard landing gear. Trying
to decipher MT’s spec sheets is proving difficult. Still don’t know what the “B”
stands for or the “50a” or “52”. Any help or suggestions will be very much
appreciated. Thank you.
John Van Lieshout
RV6A QB 85%
AeroSport Power IO375-M1S 195hp

 

[rocketman1988]

I don’t think that’s right

Vans Aircraft and MT recommend the MTV-9-B/183-50a for my
AeroSport IO-375 195hp engine. I have an opportunity to purchase
a low time MTV-9-B/200-52.
Apart from the diameters of the props what’s the difference between
the two? I know the MTV-9-B/200-52 is 78 inches in diameter and MT’s
specs list the minimum diameter as 76 inches which is too big for an RV6A.
Or is it? What is the required distance between the prop tips and the ground?
I have installed the new rubber puck type landing gear on my RV6A so the
engine rides a little higher than a RV6A with the standard landing gear. Trying
to decipher MT’s spec sheets is proving difficult. Still don’t know what the “B”
stands for or the “50a” or “52”. Any help or suggestions will be very much
appreciated. Thank you.
John Van Lieshout
RV6A QB 85%
AeroSport Power IO375-M1S 195hp

MT recommended the MTV-9-B/200-52 for my RV-10 with an IO 540 making 300hp. That prop is also 12 lbs heavier than the MTV-12 and is rated for 450 hp. I don’t think that’s the right prop for a 195 hp IO375….

 

[agent4573]

MT recommended the MTV-9-B/200-52 for my RV-10 with an IO 540 making 300hp. That prop is also 12 lbs heavier than the MTV-12 and is rated for 450 hp. I don’t think that’s the right prop for a 195 hp IO375….

MT requires the MTV-9 hub for a 375 to deal with the higher torsional vibe. It's a larger hub vs the -12 model which is where most of the weight comes from. It's not a ton of power at 195, but it hits harder from the longer stroke compared to the 180.

Found the parts breakdown. Images attached. They are both MT variable pitch props on the 9 series SAE 2 hub with 1/2-20 bolts. The 180 = 70.8", the 200 is 78.74". The 200 is way too big of a prop to install on anything other than a 10. Vans recommends up to 74" for an A model and 72 for a tail dragger. The 50 and 52 designation is a little cryptic, but the "a" means its been more aggressively pitched than a standard blade.

The minimum spec is there so you can dress the tips down if needed as they wear. It would be a waste to buy a 79" prop and immediately cut 1.5" off each end of it. It would also prevent you from ever dressing it again in the future if it were to get damaged. As far as ground clearance goes, i guess thats up to each individual. My blade is 72" on a taildragger and is already within a few inches if I go level on the ground, I'de say maybe 5-6" of clearance. That doesn't leave much room for error for getting the tail too high on takeoff or landing. There's also things to worry about like sewer grates and other uneven surfaces that may drop your nosewheel 2-3" low and eat up a lot of ground clearance. Hit that with any speed and you'll compress the landing gear another 1-2". Seems like a great way to get yourself into a premature engine rebuild from a prop strike if you go too big.

 

[rocketman1988]

Interesting

MT requires the MTV-9 hub for a 375 to deal with the higher torsional vibe. It's a larger hub vs the -12 model which is where most of the weight comes from. It's not a ton of power at 195, but it hits harder from the longer stroke compared to the 180.

Found the parts breakdown. Images attached. They are both MT variable pitch props on the 9 series SAE 2 hub with 1/2-20 bolts. The 180 = 70.8", the 200 is 78.74". The 200 is way too big of a prop to install on anything other than a 10. Vans recommends up to 74" for an A model and 72 for a tail dragger. The 50 and 52 designation is a little cryptic, but the "a" means its been more aggressively pitched than a standard blade.

The minimum spec is there so you can dress the tips down if needed as they wear. It would be a waste to buy a 79" prop and immediately cut 1.5" off each end of it. It would also prevent you from ever dressing it again in the future if it were to get damaged. As far as ground clearance goes, i guess thats up to each individual. My blade is 72" on a taildragger and is already within a few inches if I go level on the ground, I'de say maybe 5-6" of clearance. That doesn't leave much room for error for getting the tail too high on takeoff or landing. There's also things to worry about like sewer grates and other uneven surfaces that may drop your nosewheel 2-3" low and eat up a lot of ground clearance. Hit that with any speed and you'll compress the landing gear another 1-2". Seems like a great way to get yourself into a premature engine rebuild from a prop strike if you go too big.

Interesting. As the MT is a composite blade, I'm not sure how you would cut 1.5" off each tip without compromising the core. Just be aware that the -9 hub is 12 lbs heavier...

 

[agent4573]

Interesting. As the MT is a composite blade, I'm not sure how you would cut 1.5" off each tip without compromising the core. Just be aware that the -9 hub is 12 lbs heavier...

Sorry, yeah i was thinking for metal blade. Not sure how you would dress the carbon blade. Bad assumption on my part. The core may end a few inches shy of the blade tip, with the last few inches being solid carbon. That would allow at least some clean up of the tips. But I'm not a carbon guy so that's probably not right either.

 

[Walt]

Interesting. As the MT is a composite blade, I'm not sure how you would cut 1.5" off each tip without compromising the core. Just be aware that the -9 hub is 12 lbs heavier...

Actually the MT is a wood blade with a “cover”.
The -9 is still about 8lbs less than the std Hartzell so -12 will really move the CG aft.

 

[rocketman1988]

IOW

In other words, it is a composite prop.

If the heavier hub makes the cg work, great.

 

[Walt]

Maybe Semantics but... the MT blade is made from wood covered with a very thin layer of fiberglass for protection only, it is does not contribute to the strength of the blade.

MT Composite:
The presently used MT blades are in natural composite, using high compressed wood in the root and lightweight wood in the remaining body. Epoxy fiberglass covers the entire blade surface and is painted with acryl lacquer. This stainless leading edge is approx. 50 cm (20 inch) long. The outer portion is protected against erosion by a bonded on stainless steel erosion sheath. The inner portion of the blade is protected by a self-adhesive PU-strip, unless the blade is equipped with a de-ice boot.

VS Hartzell "composite":
The Hartzell ASC-II consists of a unique monocoque structure of advanced composite materials. The structure consists of carbon fiber laminates integrated into a co-molded stainless steel shank. The outboard half of the leading edge is protected with a co-molded electroformed nickel erosion shield.

Big advantage of the wood MT blade is unless the damage is very deep it can generally be repaired, the Hartzell on the other hand can have the same level of damage but the blade is not repairable.

Definition:
What does made of composite mean?
Composites are simply a combination of two or more constituent materials with different physical or chemical properties. When combined, they produce a material with characteristics different from their original properties. The two main components within a composite are the matrix and fiber.

 

[Walt]

MT "composite" blade.

 

[rocketman1988]

Thanks

Yes, there are different composites. Semantics, maybe but thanks for illustrating that both props are composite in nature…