A 7% loss of cruise speed is completely unacceptable IMHO.
Sorry I mistyped it, it’s 7kts, which means about 5%. Still way too much IMO. P28R, BTW.
But what is “very much less noise”?
You can look up various combinations of airframe, engine, exhaust silencer and propeller combination noise levels in the EASA TCDSN. It usually boils down to very rougly 3dB.
But you usually both need a less noisy propeller and an exhaust silencer Just one component alone typically doesn’t reduce certified noise level much.
The MT composite propellers are a little more expensive to overhaul than the aluminium propellers but in the process no material is lost, so there is basically unlimited blade life
That sounds like a composite prop commercial. While it’s true that some material is lost during overhaul of an aluminium prop, it doesn’t seem that big a problem in practice. Mine has been overhauled I think 4 times, it is still very well within tolerances (says MT). And the plane has been operating from a grass strip for at least the last 10 years.
Anyway, what is actually replaced at overhaul of a composite prop? It can’t just be the leading edge and the paint, considering the cost.
FWIW, this is one testimonial from a Cirrus pilot on COPA:
Just a follow-up pirep on the MT 4-Blade prop…
I now have about 20 hours behind the new prop. I like it. It is VERY quiet and VERY smooth at cruise. MT claims a few other benefits as well, but compared to the previous 3-Blade Hartzell composite on my Turbo G3, those about sum up the noticeable differences. Speed is as good or just a smidge better (1-2 knots), but I have not noticed any substantial improvement in that category or climb ability.
If you are considering this prop, do it for the reduction in noise and vibration. It is quite substantial. Everything else appears to be of little consequence (at least compared to the Hartzell Composite).
I do have one point worth noting… Although the Hartzell prop provides substantial braking action when the throttle is pulled back, its onset is pretty linear and not too dramatic. The MT prop, on the other hand comes on all at once and can be cause for a little excitement if you are not used to it or expecting it. I used to pull the throttle all the way back (with the Hartzell) if I was a few feet over the runway and a little hot and glide it on. If you do this with the MT prop you will fall like a stone and bounce down the runway. (Don’t ask me how I know…) I’ve done a bunch of tests to confirm this behavior and its quite noticeable. Its that last little bit of throttle pull where the MT prop really brakes hard. It comes on very hard and all at once. You can even hear it when happens (actually sounds like BETA thrust reversing). My instructor (Cirrus Certified) also noticed this during the test flights during the initial installation. Perhaps related, the MT prop also seems to want to carry a bit more power during landings. Both of these qualities were noted on two different SR-22’s which had the 4 bladed prop installed. If you have the prop installed, you may want to take some time to get your “numbers” re-established for landing profiles..
Its a great prop! Very quiet and smooth. Folks at my shop often go outside when I take off as the plane apparently sounds like a turbo-prop on departure
Achim, while the statement is somewhat emotional, I like it! If you knew Gerd Muehlbauer you would know that he is an emotional guy, and I like that too. Actually I like it better than statements by robot-like managers who will never answer a question in a concrete way and never show any emotion.
My 5 c
Peter,
they offer them for extreme applicatiosn like Air Races, because some pilots wanted them. One of the Chief Engineers told me (last week) that while some people claim the full carbon composite props are stiffer they (the company) do not think it has an advantage and they usually do not recommend the much more expensive carbon blades that also cannot be repaired as easily as the ones with the wooden core
This statement of Gerd Mühlbauer clearly was a low-light in the history of the company. A very childish and unprofessional answer to unfair competition.
A simple statement stating the facts would have been enough, possibly combined with a cease and desist. MT has nothing to fear, they have been eating Hartzell’s and McCauley’s lunch for years and they will continue doing so. The vast majority of new GA aircraft are equipped with their props and the retrofits are very popular. They should just continue their work and let the competition do their thing.
There was some stir in 2014 which caused Gerd Muehlbauer, the president of MT, to publish this open letter which can still be found on their website, see link below.
Allegedly Hartzell made some public claims about MT-propellers, including showing a video in which an MT-prop blade was destroyed by an object simulating a bird strike, which brought forward this reaction. I have not seen the video and could not find it on the net but MT claim that the set-up to the demonstration by Hartzell was done with the sole purpose of destroying the blade and not in line with the tests required by EASA and FAA simulating a bird strike for the certification of props. MT further mention that the “Hartzell-test” would destroy ANY prop blade regardless of which material it would be made of, implying that Hartzell props would also be destroyed if they were subjected to such test.
Enhanced cruise performance by 5 to 8 kts
Given that this improvement would be happening at the top end of the perf curve (well, obviously 
) where most of the drag is parasitic, and given that 5-8kt is about 5% of the IAS, that would correspond to about 10% more thrust, and where is this amazing free lunch going to come from?
If the efficiency of the Hartzell prop is say 90%, it would imply that the MT prop is approximately 100% and that would be Nobel Prize material, at a level similar to discovering a method of interacting with gravity that doesn’t involve the manipulation of impractically large masses.
It is easy to get extra 10% by increasing the RPM (by about 5%) but they aren’t doing that. You would also have ~10% more fuel flow.
If I could get 5kt extra at the same fuel flow, and measurably less vibration, I would buy the MT prop tomorrow.
Also MT also produces full composite/carbon props. They are more expensive, but available – but MT says there is no advantage when compared to their props with a wood core
Why do they offer them?
Silvaire
all of the newer MT blades are covered with carbon fibre (not glass) at the root, plus glass fibre on top, AFAIK. I do know the MTV-14 is made like that.
Also MT also produces full composite/carbon props. They are more expensive, but available – but MT says there is no advantage when compared to their props with a wood core
My comments were specific feedback from people doing work on them. Albeit a small sample size I confess. Nothing to do with myths.
I met them and like the guys there as well.
