Just MT Propeller

[RVjim]

My purpose in starting this thread is to provide a place for the exchange of information in the form of an interactive discuss about MT Propellers. Since MT Propeller is a manufacturer of propellers with both aluminum and wood (natural composite) blades with from 2 to 6 blades, a fairly broad discussion could result.

Since I am more than a little concerned about off topic comments, and advocates that "require" their choice for everyone, Doug Reeves has offered to monitor this thread more closely than usual.

I would like to start this thread with some basic information.

First, the MT propeller number is almost like a finger print of the aircraft for which the propeller was designed. This is because the propeller blades are designed to the aircrafts performance and engine being used. Of course, a family of aircraft with the same performance and engine (like an RV with a 180 hp Lyc (I)O-360) would use the same propeller design. Although the propellers designed for the RV family could have either two or three blades.

I have two MT Propellers for my RV-6A. A 3 blade MTV-12-B/183-59b and an aluminum 2 blade MTV-15-B/183-402. The first part of the number before the / defines the propeller hub. The number after the / defines the blade.

The first part of the propeller assembly number identifies the engine used. So, to me, the blade definition is the more significant portion of the propeller number. For examble, on my 3 blade MT propeller, /183-59b, indicates the propeller has a 183 cm (72 inch) diameter. And the -59b is a specific wood blade design in the symitar style of blade.
And on my 2 blade propeller, 183-402, is again a 183 cm (72 inch) diameter propeller, while the -402 is a specific aluminum blade design.

I should mention that MT Propeller ships the propeller assembly from the factory with a finished spinner assembly to match your cowling installation. If the customer provides the correct spinner diameter and cowling information, the propeller and spinner assembly simply bolts to the engine and is ready to go.

Why have both aluminum and wood blades available?
The 2 blade Aluminum blade propeller makes a very good propeller for the Lycoming (I)O-360 180 horsepower engine. And this is the typical propeller design we usually see and operate here in the USA.

However, the weight of the aluminum blade propeller has some limitations. Particularly the weight of the aluminum blades themselves.

For the Lycoming (I)O-360 engine, the MT Propeller Aluminum 2 blade propeller assembly weighs about 56 pounds, while the ?Natural Composite? 3 blade propeller assembly weighs about 44 pounds. Most of this lower weight is due to the light weight of the 3 ?natural composite? blades.

So, the first advantage of the 3 blade MT propeller is that it has 60% less gyroscopic load than the Aluminum 2 blade propeller. This means the propeller has a lower flywheel effect on start up and shut down. And the aerobatic loads to the propeller crankshaft are greatly reduced.

A second advantange of the lighter weight 3 blade propeller is not so obvious. By adding counterweights to the propeller blades, the propeller can start in the coarse pitch (low RPM) position, and be controlled to the low pitch (high RPM) position by the governor.

So what good is this?
With the loss of oil pressure, the counterweighted blade propeller automatically goes to a cruise flight pitch. In this position, the propeller drag is reduced to 5/8ths of the drag from the standard propeller blades in the low pitch (high RPM) position.

The counterweighted blade propeller is excellent insurance for aerobatic flight. Even with an inverted oil system, in zero G maneuvers, it is fairly common to momentarily loss oil pressure. With the counterweight blade propeller, the RPM decreases as the blades move to a higher pitch, thereby preventing engine and propeller overspeed that would otherwise normally occur.

In the event of an actual engine failure, the propeller blades will again go to a cruise pitch position with the resultant lower propeller drag. I understand the Lancair people really like this feature.

I would think the RV-8?s with the Sam James cowl would like this propeller, also. Even with the extended hub to clear the cowl and counterweighted blades, there is no aerobatic restriction on this engine/propeller combination.

MT Propeller also makes fixed pitch propellers. The blades are manufactured to the same processes and standards as the constant speed propeller blades. Each blade has the same stainless steel leading edge that is three times more resistant to water and sand erosion than Aluminum.

Briefly about myself:
I operate an FAA certified propeller repair station.
At this time, the only propellers I service and sell are MT Propellers.
I find I have really enjoyed talking with people about their project and how they plan to fly their aircraft. (Some low and fast. Some high and fast. A few actually wanted economy. J )
I originally spent $6,000 to get my RV-3 flying. And have spent at least twice that since then with various changes, including a new engine. Even so, to spend another $10,000 (5 years ago) for an electric CS propeller was a tough decision. But it has been the one most significant change I have made in the overall perfomance and reliability of my RV-3.

Regards,
Jim Ayers
RV-3 sn 50 LOM M332A engine MTV-7-C/L175-112 propeller - 650 hours TT airframe

[hydroguy2]

how about some real performance numbers from the 2 blade aluminum MT on a IO-360 RV-7?

[Kahuna]

Jim,
With a thread title of "Just MT", do you not want any discussion comparisons of the MT to other manufacturers? Seems most folks who are interested in MT discussions are interested in the discussions as they pertain to the alternatives. Without comparitive discussions for baselines, how do we discuss any attributes?

Best,

[Brian Vickers]

Jim,
I am thinking of using a fixed pitch MT on my simple, light weight O320 RV4, currently in the finishing stages of construction. I live in the northwest US. The rain has me desiring the metal edged MT. Plus, it would be interesting to try something different. I'm concerned about spending so much money and possibly ending up with a prop that is pitched too far on either end of the RPM spectrum. Do you have any experience with a set-up like I'm describing?

Sincerely,

[Russ McCutcheon]

Hi Jim,

I have an MTV-15-B/183-33 bolted to a Lycoming angle valve A1A 200HP. I have 410 hours on it in only 18 months sense its last O/H, the O/H was done at MT USA in Florida, they did a great job I think but it took about 4 or 5 months. The prop had been badly neglected by its previous owner and required a hole new hub assembly and new custom blade ferrels to accommodate mounting my old blades to the new hub. I also wanted new erosion strips (metal leading edges) but they neglected to do this and just filled the pit marks which have now eroded out again from flying in the rain, not to mention a new ding caused by me after the O/H.

I like what I got from MT USA but I am looking for someone closer for next time and someone that will have my prop for weeks not months, You seem to have a passion for MT props so you are in the running along with maybe American Propeller.

So are you the full meal deal MT prop shop? Authorized to do any and all service including the blade lag bolts if necessary, erosion strips and refinishing?

Hear is what I want next time.

1. standard hub O/H
2. new erosion strips
3. blade re finish
4. And I want this done without the ferrels being removed if at all possible, this is expensive and they just put them on there last time.

So can this be done and if it?s straight forward what would the cost be? And if we set it up well in advance can you have the parts so you can do the work in short order?

So far getting this prop serviced correctly and in a timely fashion at the same time has proven impossible!!!! I love this prop but I want some good service!!!!

Don?t PM me just answer hear so everyone can hear what you offer at your shop, everyone with an MT will be interested in your answers.

Russ

[Dennis Madden]

Ditto for me...
DM

Originally Posted by Brian Vickers

Jim,
I am thinking of using a fixed pitch MT on my simple, light weight O320 RV4, currently in the finishing stages of construction. I live in the northwest US. The rain has me desiring the metal edged MT. Plus, it would be interesting to try something different. I'm concerned about spending so much money and possibly ending up with a prop that is pitched too far on either end of the RPM spectrum. Do you have any experience with a set-up like I'm describing?

Sincerely,

[jclark]

Originally Posted by Brian Vickers

Jim,
I am thinking of using a fixed pitch MT on my simple, light weight O320 RV4, currently in the finishing stages of construction. I live in the northwest US. The rain has me desiring the metal edged MT. Plus, it would be interesting to try something different. I'm concerned about spending so much money and possibly ending up with a prop that is pitched too far on either end of the RPM spectrum. Do you have any experience with a set-up like I'm describing?

Sincerely,

MT has TWO (2) different pitches for the 2-blade props offered for the O-320. There is a difference between the one for an RV6/7 ("wide-body") and an RV4 and I think RV8 ("narrow body") sporting 160 HP.

Just be sure an make sure your order is clear if you decide to go that route.

James

[gmcjetpilot]

Originally Posted by Brian Vickers

Jim,
I am thinking of using a fixed pitch MT on my simple, light weight O320 RV4, currently in the finishing stages of construction. I live in the northwest US. The rain has me desiring the metal edged MT. Plus, it would be interesting to try something different. I'm concerned about spending so much money and possibly ending up with a prop that is pitched too far on either end of the RPM spectrum. Do you have any experience with a set-up like I'm describing?

Sincerely,

Really for a fixed pitch prop consider the Sensenich, which is made for RV's. A prop is not designed as a stand alone component, it must match the airframe and engine to get the most efficiency. For props one size does NOT fit all. Yes it weighs more but maintence and rain wise, its a no brainier. Also a RV-4 needs weight on the nose with a O320 to get full pass and bag weights, while not exceeding aft CG. Metal also can be re-pitched. Lets say a few years from now you do some plane mods and reduce your RV's drag, with new wheel pants, cowl and other clean ups. YOU CAN REPITCH the Sensenich. Also the performance of a metal props and their thinner blades are better than thicker wood blades. Van tested 8 props, all constant speed props except one, a Sensenich. It came in 2nd behind the Hartzell BA prop!


(Note: the Sensenich if allowed to over speed was faster in this typical cruise condition at 8,000'. Van estimated 2,500 rpm cruise would be about 207.9 mph (from 210.0 mph at 2730 rpm). I believe that est is a little high. Regardless the Sensenich is an efficient prop you can bolt on and forget about.)

[pvansrv3]

I have an RV3. It had a fixed pitch wood prop and was flying just dandy. In the interest of higher performance and higher tech, I replaced the fixed pitch prop a few years ago with an electric MT constant speed one, bought it through Jim Ayers.

The conversion process was straightforward, although it does affect your pocketbook to a fairly large degree ($8000). I ended up making a new instrument panel to fit the governor, and that entailed even more money spending for new goodies, but that is not the fault of MT.

The MT came with it's own spinner, fits fine but does not have the same profile shape as the original so the lines of the fuselage/cowl/spinner are not quite as nice as they used to be.

The take off performance was great and is now stellar. Initial climb is unbelievable. I fly from a 2000 foot strip and when at the departure end I am at 900 feet AGL. That is a huge improvement, not to say it was a needed improvement..

Cruising speed is the same, but at a lower rpm. Fuel burn might be a tad lower at the same cruise speed.

Max speed is at most 1 mph higher noted by flying next to an RV6. I have a Lycoming O-320 E2D by the way.

Landing is drastically different. The plane is a brick with the throttle closed in the pattern, you have to keep 2000 rpm to make a normal gliding pattern approach. I think there is such a great percentage of airplane in the propwash, and the prop is such a fine windmill sucking energy from the air that the braking effect on a light airplane is enormous. We leave the prop governor set at 2100 rpm and leave power in on approach. You can easily do a go around at that prop setting since the plane is light and powerful.

I can now safely fly in rain, and that happens here in the NW, so that is a great benefit.

Would I do it again? No. Just not worth it. But I would never know that without having done it, and that is what experimental is all about.
My $0.02.

Peter

[Brian Vickers]

Hi George,
I have previously communicated with you about the Sensenich props. Your knowledge and insights are very much appreciated. I agree with all you say and would rather have aluminum. I particularly agree with you about re-pitching and prop weight. The article you have posted is for the unrestricted prop designed for the O360. I am installing an O320. The RPM restriction is a deal killer because of my desire to fly sport aerobatics. Cruising at 2,600 RPM's or less is not an issue for me.

I attempted to order a prop from Catto but they would not return my phone calls or email. With more than a 12 month wait for delivery I can understand why.

The fixed pitch MT is a viable option. Weather resistance is a huge plus, and the price is reasonable (same as Sensenich). Rob Ray (Smokey) is very happy with the fixed pitch MT on his O320 RV-4. He is the only data point I am aware of. I would love to hear from anyone else that is operating an O320 - RV4 with a fixed pitch MT. Or anyone using the restricted Sensenich and occasionally over speeding it for brief moments, like in a diving maneuvers. Is occasional over speeding an issue? I?m trying to learn all I can.

Sincerely,