Well, another small update.
The prop finally arrived and the airplane is now in the hangar being returned to flight. We will have to do a first test flight next week hopefully, which will be a 2 hour (min) break in flight with the engine at 75% and at around 6000 ft AMSL. It will then land at the location of my normal maintenance, where some finishing touches will be applied. With luck, we should yet be able to catch some of the flying season.
The major issue here really was the waiting time for the prop. It is totally amazing that it takes up to 9 months for a new prop these days. So we are very carefully looking into possibly acquiring a reserve. Had I known it would take this long, I would have most probably taken the offer (more expensive however) of a 2nd hand prop sourced from MT. But who could have known.
I am looking forward to find out how well the 3 blade prop works. Also it will be interesting to see if we can get the noise class reduced. I am also waiting to see what this will do for weight and balance, probably a 10 kg or so loss of payload and a CG slightly further forward.
What has become brutally clear after 9 months standing time is that the airplane will need a respray soon. We have to see how to do that and where, given that budget reserves will probably be exhausted after this repair.
Good news MD, great to see that you’ll be airborne again soon. You are going to enjoy the smoothness of that 3-blade prop.
Good luck MD with your aircraft, people will tell you 3 balades are draggy, noisy, slow, heavy but 3rd blade looks cool and adds to redundancy 
Ibra wrote:
people will tell you 3 balades are draggy, noisy, slow, heavy but 3rd blade looks cool and adds to redundancy
Well, what I read on Mooneyspace is that I’ll probably loose 1-2 kts of top speed in return for better take off and climb performance. I will loose some 10 kgs payload and the CG will move forward. Hopefully however I will gain the noise class D in Switzerland, which would be really neat (I was “B” with the 2 blade which meant surcharges of up to 80 CHF eg in Samedan).
3 blade props are supposed to be quieter than 2 blades anyway… I originally thought it also gives better ground clearance but it does not, same diameter.
Reason behind buying the 3 blade is that at the time we asked they did give us a delivery date for a 3 blade but none for a 2 blade. Even though they did not honor that delivery date in the end, we took the lack of one for the 2 blade that possibly could not deliver at all. Which is mindboggling, as it is not a prop proprietary to the Mooney, it is used on many other airplanes too.
My lesson is that I will have a look around for a used prop which fit onto the airplane.
My 3B Hartzell has a 25mm smaller radius than the 2B one used on other TB20s.
No change in performance.
Most 3 blades on mooney are the same radius as 2 blades (I measured and one can look at the specs) but people will tell you there is more propeller clearance on 3 blades, I am sure they mean on climb gradient
Peter wrote:
My 3B Hartzell has a 25mm smaller radius than the 2B one used on other TB20s.No change in performance.
Did you have a 3-blade from day 1, from the factory? If so, standard fitment or a customer option?
I’m pretty sure our TB10 must have left the factory (in 1989!) with a 2-blade, but it’s had a 3-blade the whole time I’ve been involved with it. Looks much cooler.
Am not sure at what horsepower it makes sense for reasons of physics to go from two blade to three blade, but for the typical hair dryer GA engine am pretty sure there is no need to have three blades. Most Beech 18 (450 HP) and all Harvards (600 HP) have two blade propellers. I understand the argument if propeller tips are going supersonic, or there is a need for propeller clearance in the design, but generally three blades add weight, complexity, cost and reduce efficiency. @lbra wasn’t sure whether you were tongue in cheek when you suggested three blades added redundancy. There was a single blade asymmetric propeller design, but am not sure you didn’t mean that :)
wasn’t sure whether you were tongue in cheek when you suggested three blades added redundancy
Tongue in cheek, this guy does not have many blades in backups…
RobertL18C wrote:
. I understand the argument if propeller tips are going supersonic, or there is a need for propeller clearance in the design, but generally three blades add weight, complexity, cost and reduce efficiency.
Well, in my case I went for 3 blade because there were no delivery positions for 2 blade. And because I was lead to believe that the 3 blade will be quieter and therefore will reduce my noise class, which over the years may repay some noise taxes. Other than that, I would have gone back to 2 blade.
