propeller anyone ?

Apart from meeting a whole lot of cool people in need of gently used Yak parts, another upside to parting out a 52 is pimping your own ride.

As you may already know, the factory just started making 52's one day with sheet metal control surfaces. Nobody can quite tell why. A couple of years later, just as mysteriously, they stopped. Doomed to short lives in service, these Sheet metal control surfaces are seen quite rarely now in stock tricycle-gear 52's 

By the time Czech Mate, (the Red, Black and White and checkered 52 which can be spotted in these pages), came into my life, its previous owners had already switched the Rudder and Elevators to Fabric at great expense, due to plentiful cracks in the sheet metal. And as for my sheet metal Ailerons, it's not a matter of if, just when. So a pair of fabric covered ailerons from the parts Yak have been reserved for the day Czech Mate goes to the auction block and its next owner.

Similarly, a low time V530 paddle prop and hub came with the Parts Yak, and today it is featured at a discounted price under the main page's 'shop' button, so please check it out!
It's been doing stellar service for the last two weeks while Czech Mate's original prop and hub received a makeover.

​Whirlwind Propeller, right here at KSEE, do an amazing job of refurbishing tired V530 Paddle prop blades. Two weeks after I dropped them off, mine were standing there at Jim Rust's shop, wrapped in clear poly, showing off their crisp white paint, red tips and that amazing Nickel leading edge. 

Mouth watering.

Vlad Yestremski, meanwhile, had been rebuiding the hub. In the short animation below, 

you can see a grey colored cylinder behind the red piston which turns linear movement into blade rotation. It is lined with an  impregnated Baekelite-type material which, where I come from, used to be called Tufnol.

Grasp your Vperod blades by the counterweights, and notice some rotational play as you apply opposing forces around the blade axis. (Do this after the engine has run and oil is in the hub). That movement you feel is largely due to wear of the integral Tufnol sleeve inside this grey collar.  

If you were ever a Lycoming owner in a previous life, you might have been in awe of how the diminutive IO360 could not only produce 200 HP but also how its matched Hartzell or McCauley put that out through just 2 blades. Then the 390 upped it to over 100 HP per blade. But all this time, humble Vperods have been quietly shovelling 180HP per blade into Yaks slipstream, so, being sized for the job, it's no surprise the Vperod Hub is a beefy piece of kit.

That axial blade play mentioned above, which comes with age, allows the blades to have slight variation in their angles of attack under power and is thus a significant source of in-flight vibration.

If you subscribe to the Red Star Pilots Association's quarterly magazine RED ALERT, in Summer 2017's issue, Socal Propeller balance wizard Jim Fackler wrote an excellent article about the method and history of Propellers' dynamic balancing. He's quoted here:

"In physical terms, each 0.1 IPS equals about .001" physical displacement of the propeller at 2000 RPM.  The average out-of-balance on an M-14 or Housai is about 0.4 IPS with the real shakers coming in at 0.6 IPS and up."

As you can see on the instrument readout for Jim's final balance....

the combined Vlad/Whirlwind/Fackler therapy resulted in .01 IPS.  To sit in the plane, it certainly feels like you are, by Yak standards, sitting on the couch. 

" Honey, I need two beers, one with the top off...and Hey, where's the remote?" 

Yeah, might as well dream at the airport, because that dog don't hunt at home. Ah well...

Thanks Vlad, Jim and Jim. 

​A happy customer.