On Thursday MT Prop at EDMS airport (Straubing) mounted the MTV-14D prop on my SR22. I have an agreement with MT to test fly the prop for two months. If I like it i will buy it – if not my metal 3-blade Hartzell prop will be put on, free of charge.
The Prop:
- This version of the MTV-14 has the new NICKEL leading edges. They are much harder than the steel ones, and they make them extra wide because analyizing prop damage they found out that many times the damage is not only at the leading edge but further in. Also the wide nickel edge prevents erosion of the paint. The metal part can easily be changed when damaged.
- The prop is 1 inch shorter in diameter than the standard SR22 prop. I am glad it’s not more, because that makes them ugly … Nevertheless 1 inch can be enough to prevent damage, especially landing of grass runways
- is the classic MT wooden core type. It is covered by carbon fibre and glass fibre. One of the main advantages in my eyes is that the engine will not be damaged in case of a prop strike, because the blade/s will break before the bearings etc of the prop are exposed to any significant load. Also a damaged/broken blade can be repaired, Typical costs for a broken (!) blade start at € 500 (compare with price for one metal blade …)
The installation/details
- took about 2.5 hours plus 1 hour for dynamic balancing. The prop measured within the tolerance, no weights etc. were needed.
- the TKS pipes are pressed flat on the MT prop (round on the Hartzell), according to MT this solution works better
- Various spinners can be had: polished aluminum, Carbon fibre, chrome plated plastic
First (!) impressions:
- The prop looks much better than i feared, actually after one day i really like the looks
- The (polised aluminum) spinner is not as nice as the original one: it is a little bit less pointed (it’s really just a little bit, but I am crazy for details …), and it has a second bulkhead for stabilty in front of the hub (solved differently on the Hartzell), and therefore 4 additional screws. Also it does not have the curved prop (spherical? sorry, don’t know english word) prop outlets. But these details are really very minor
- When we did the balancing my iPhone db meter measured almost exactly the same noise inside the plane. The sound is very different though. At 1000 rpm the prop whistles and you hear the engine much more than before.
- Since my 3-blade was perfectly balanced (by Jim Barker, Cirrus specialist) i could not really feel much difference in vibration. Putting the hand on top of the glareshield there’s practically no vibration (most SR22s do have some vibration here).
First flight
- I immediately noticed the better acceleration on take-off, but have no data
- The initial climb is improved by at least 200 fpm, i am sure
- the governor reacts quicker because of the lighter blades (less intertia), so when going from cruise setting to full power/highest rpm it feels like it “bites” much quicker
- in cruise i did not feel much difference in noise or vibration
- Cruise is maybe 1-2 knots better down low (have not flown above FL90 yet)… but i can’t really tell know. I am pretty sure it’s not slower. I tod them that I’d accept 1-2 knots slower but that I’d be back for my old prop the next day if it was more than that.
The biggest difference:
- Yesterday I did my yearly IR check and bi-annual SEP check at the same time and for that you need to do a dead stick landing on the airport. Although i usually have no problem with that I would have landed 100 m before the runway … I had to add a lot of power to make the runway!
- We did some more landings and two IFR approaches at EDMA airport (Augsburg). While 12 inches of power would be enough for a 3 degree glideslope with my old prop I used 18 to 20 percent with the four blade.
- If you reduce power too soon before the threshold the new prop has the effect of barn door, really! The nose goes down and the sink rate is extreme! I think that will make steep approaches possible … and i have heard from other Cirrus pilots that 3000 fpm descents are possible without going over the red line (although i would never do that in idle, have to test what that means for pwr on descents)
Here’s some pictures:
Installation at MT prop
I wonder why they use a white bulkhead for a polished spinner, and that will be changed at my next visit (i want a poiished backplate, becasue you can see the white behind the blades!))
preparing a/c for dynamic balancing
Looks pretty good, doesn’t it?
I think it looks better than the original. The shape of the blades is very pleasing
Flyer59, take my word for it, you will be very pleased with the MT prop, and MT as company to deal with. Excellent product, excellent people. Enjoy your time with them, and decades of happiness with the prop. The nickle leading edges are worth the cost, during 35 hours of testing in difficult conditions, I did not put a single mark in a leading edge.
MT took a long time to figure out nickel leading edges, but in the here and now they would certainly be a lot better than stainless. I don’t know how MT are making theirs (their stainless leading edges are relatively crude) but the best kind are formed to a numerically defined 3-D shape to fit a recess in the blade. Blade and thin inconel sheath then match with minute precision because the blade recess is manufactured to a mating numerically defined 3-D shape. The inconel leading edge can then extend further to the hub and wrap around the tip, if wanted. It’s been done that way elsewhere for roughly 15 years. Here one example, this one I think with hollow carbon fiber blades.
And the tip…
I have the same ‘barn door’ braking effect with my MT prop, static RPM on the low pitch stop is redline on mine… so when it goes full fine it’s a great brake. Not so good if the engine quits, but it makes landing easy.
Yes, you are right – but in the Cirrus you’d use CAPS anyway if you can’t make s runway!
Very pretty !
I guess I have to ask them now whether they also offer the nickel edges for my 3 -blade when it is due for overhaul.
Many happy hours with the new prop.
Thanks!
I like it too. I would say some minor details were nice with the old props (spinner a bit more pointed, polished backplate) – but all in all itÄs a great product i think.
More testing tomorrow :-) (Sorry, wife, have to go propeller testing!)
Flew 2 hours yesterday with new prop. My impression is that it’s a bit faster than before even at low altitudes. Still have to get used to the braking effect. No way to pull the power too early when landing … that feels like activating a reverser!
Acceleration on T.O. feels much better, climb is improved too!
I’ll share some data later, first have to fly to my other office :-)
Wat would be the physics behind this type of prop having a greater braking effect?
It’s just that one more blade … I have no other explanation. But it’s really astonishing. I just landed on the grass runway in Rakovnik ten minutes ago and i was standing after 350 meters … that’s really my new records
