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Warbirdsolutions

Active Member
I know this subject has been beat to death, but I have not read in previous threads on the subject of specific MT props. Van sells the MTV12B/183-59B for the O-360 which is 72" diameter. I am hoping someone has real experience with THIS prop. I am deciding between the Hartzell 7497 Blended Airfoil prop and the MT. I have had 3 MT 3-blade props in the past and really liked them primarily for the smoothness. Les Dowd at Hartzell says the 74" blade is as long as can be used with a non-counterweighted IO360 using high compression pistons and electronic ignition. Diamond aircraft uses the same MT prop as Van's sells on their certificated airplanes as mentioned above so it is probably the most ideal prop for the higher HP IO360. Any feedback on the MT prop listed above would be greatly appreciated. I would love to hear from anyone who may have used both as well. I expect that the MT will suffer a few knots at wide open throttle so a cruise comparison would be the most helpful. Sorry if this thread is redundant, but I'm hoping that some of you may have experience with this specific prop.
Thanks very much in advance,
Brad
 
Brad,

Apart from Primers, this is one of my favourites !

What you want from a propeller is very subjective.

Some people want ultimate speed.

Some people want best economy.

Some people want best price.

Ultimately - if you choose an MT 3 blade propeller, you get the best, the finest, the smoothest, the most sexy looking , the lightest propeller.

However - I am not biased (Herr Albrecht please note)

Seriously - it is a good prop, it performs well, it gets you out of short strips, cruises very smoothly, doesn't go as fast as some, but is lighter and is well built and one of the best things - comes with it's own spinner, so no faffing around there..
 
MT vs. blended

My first RV-7 started life with the MT three blade offered by vans and I later switched to the new 72" blended airfoil Hartzell. I flew both for well over 100 hrs each. My engine was a 180hp lyc with high compression pistons and Lasar ignition.

I liked the MT for looks, smoothness, and braking in the patern and landing. I have heard someone quoted as saying that with RVs you "land the prop" more so than landing the plane. The point being that a each prop completely changes the way your RV will land. I think this is a very true statement. With the MT my 7 was VERY easy to land. As soon as power was pulled, the prop would slow the plane to landing speed in a way that three point near stall landings were the norm and very repeatable.

What I didn't like with the MT was its durability. The prop was delivered with a nickel sized knot in the face of one blade, this was repaired free of charge. Then after flying for awhile the blades developed cracks about 12" out from the spinner. The cracks were perpendicular to the leading egde and on the face and back of both blades. MT replaced the blades under warranty. This happened a second time and MT replaced the blades once again. At this point I decided to sell it with the brand new blades and a fresh check out from MT's rep in Florida.

I liked the Hartzell for its price, smoothness, durability and speed. It flew nicely and was a few knots faster than the MT.

If I had to pick a favorite for flying I would give the edge to the MT. However, the headaches from having it repaired would keep me from buying another MT. Oh, and the price!


I hope this is helpful. This is just my experience, YMMV.

Keith
 
Further to last......

There was an SB out a couple of years ago dealing with extra carbon sheathing on the prop.

That - I believe cured the surface cracking issue.

Because of rogues at our airfield damaging our prop - it had to go back to Germany. They did the SB during the repair.

On the landing topic.

I do not land full fine - always about 1/2" out, which would be about 2350 under power.

Makes for a much better landing and still gives plenty of performance on the go around.
 
Mike and Keith,
Thanks a million for the feedback! I have owned 3 MT props in past years and never had an ounce of problem with any of them. Each of these props were on IO540 Lycs. I love the smoothness of these props but I have read so many opinions that the M/T is too much prop for the IO360 and so much slower. So, before I give up on the MT and use the 7497 Hartzell BA, I want to be as sure as I can that the MT really is Not a best choice. I am using an IO360 with 10:1 pistons and elect ign so MT has suggested a different prop design which uses a 74" 3-blade instead of the 72" offered by Van's. No idea how this prop might do, they say it will have better performance but who knows.....
Thanks again,
Brad
 
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