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500 Performance Loss With Pma Blades


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I'm on a job right now with a 500 and an Astar. The 500 is pretty much incapable of doing anything in the mountains in the summer.

 

You end up temping out at 80 psi torque.

 

You might as well just park them all summer and only pull them out of storage come winter time.

 

If you take a PMA blade and feel along the abrasion strip, you will see that they have a divot on the top and bottom. Current theory is that this disrupts the smooth airflow enough to lose 200 lbs of lift. The question is, did they design this on purpose to try and curb blade cracking? Or is it just shoddy design?

 

All I know is that I fly both Astars and 500's and feel much safer and comfortable in the Astars.

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Interested in your comments about that divot in the blades Jet B, seems to be the most logical reason we could come up with as well, be like having permanent dirty blades with disrupted airflow across the top skin. The reasons for it being there ?..idea's anyone ?? and the hundred thousand dollar question..Can it be fixed?

Also what sort of Alt's and temps are you temping out at ?

 

Cheers TT

 

As for 500 vs Astar comfort, I must admit my head isn't pounding so much after a big day in the Astar compared to a big day in The 500 :wacko:

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Interested in your comments about that divot in the blades Jet B, seems to be the most logical reason we could come up with as well, be like having permanent dirty blades with disrupted airflow  across the top skin.  The reasons for it being there ?..idea's anyone ??   and the hundred thousand dollar question..Can it be fixed?

Also what sort of Alt's and temps are you temping out at ?

 

Cheers TT

 

As for 500 vs Astar comfort, I must admit my head isn't pounding so much after a big day in the Astar compared to a big day in The  500 :wacko:

 

From what I understand, a big 500 operator from the coast has come up with a way of smoothing the divot, with a filler.

 

One of my buddies who is a contract engineer found out how to do it from someone in B.C., but unfortunately because it isn't approved, our DoM didn't want to try it. I think he was open to the idea, but upper management and the lawyer types probably shut him down.

 

Maybe I'm the suspicious type, but I think when M.D. decided to let pma blades be made, they said here are the design specs... Wow, a blade designed to still fly but carry 200 lbs less weight. This might fix those Crazy longline Canucks who keep cracking our blades...

 

And I was temping out yesterday at 4000-5000' 15-20 degrees C.

I thought this 500 was having some heater line leakage or something, it just seemed a little too weak, but the power check numbers checked out according to maintenance. I parked the turd bird and am flying all the bags and crews with the Astar now. Much better. :up:

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Maybe I'm the suspicious type, but I think when M.D. decided to let pma blades be made, they said here are the design specs... Wow, a blade designed to still fly but carry 200 lbs less weight. This might fix those Crazy longline Canucks who keep cracking our blades...

 

MDHS actually had nothing to do with the production of the PMA blades. The blades were produced by an enterprising manufacturer, who saw an opening in the market due to MD's excessive price and inability to manufacture a reliable blade. PMA approval is a function of the FAA and has nothing to do with the OEM, hence the lawsuits that are always going on concerning proprietary rights. The greatest problem occurred when MD moved their blade production from Culver City to Mesa, leaving all their skilled employees behind in the process! The blades suffered from never ending problems with abrasion strip delamination, causing never ending warranty returns, which in turn, hammered operators and repair facilites, as there was inadequate cpacity available to handle the volume of blade repairs. If I had a new blade delaminate during this period, I would send the entire set in under warranty and get the strips on all 5 blades replaced at the same time. MDHS agreed to this!:shock:

 

The PMA blades were significantly cheaper, available, reliable and had a higher service life. The problems with blade failures came as the number of hours in operation grew and they hit real world operating conditions. All this time, MD were trying everything to STOP operators from moving to the PMA blades, or MD Service Centres from selling the blades.

 

I never did operate the PMA blades, but must admit I had never heard of any performance loss with them until now. I did however solve all the problems I had with the 500's - I sold them all! :up:

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