REFLECTOR: IMPORTANT MT PROP INFO & QUESTION

Wayne wowens at darientel.net
Thu Mar 17 20:52:31 CST 2005


 I know you had one of the Serrano's Vibetech balancers; was the weight
of the blade so far off in comparison to the other two that it was simply
and practically impossible to match them up in balance,
I
 or did the
difference in thickness create a pitch differential from the other two
blades that created a thrust imbalance rather than a mass imbalance? 
The blade balanced with the others to about 0.06 ips but wasn't consistent at various rpm's. The wobbling pitch change motor and the poor tracking were probably a factor.


 I'd
also be curious as to how Ivo handled the customer service aspect of the
problem.
They were fairly prompt about supplying a blade. When I called and said the thickness was throwing off the crush plates they asked me to mike the blades at the holes and send the dimensions with the blade I was returning. After he made another batch they finally found a reasonable match. Back and forth took a couple of weeks.

I dinged a tip not  long ago and had to cut 1/4 inch off all the blades
The blades are not hard to statically balance. You put the heavy end on a knife edge through one hole and weigh the other end on a postal scale. Then add a few buckshot to the hollow torque tube. Pack it in with rubber plug and centrifugal force does the rest.My Dynamic balance weight consist of about 2 inches of extra SS foil tape  on one blade under the regular foil tape.

Monitor the torque closely at first. It seems to stabilize after an hour or two. I keep checking and don't see much loosening. Early on I over heated the engine and the blades needed to be retorqued after that.

    A thoughtful analysis would be helpful to any others who may eventually
consider the IVO prop on a powerplant that is appropriate for his propeller.
I don't know what IVO is selling now but when I bought my prop the brush holder was do-do.  They were slot car brushes and would not last. I found a DELCO brush holder assembly for a CS130D alternator that approximates closely the spacing on my brush rings. They last fairly well. You have to saw off lots of extraneous stuff and make a bracket.

My engine is the 230 HP Soob 6 cyl with a 2.18:1 Marcotte gear drive.
As for performance,We live at sea level  on a 3600 ft paved strip 45 feet wide surrounded by 100 foot pines (like landing in a hallway) and with two on board and 40 gallons I can still use up 1200  feet getting airborne. After that my climb rate is 1200 to 2200 feet per minute initially depending on load. After I eventually move the radiator (pregnant guppy lot of drag) and improve the oil cooling I expect another 10 kts over the 160 kt top speed I can get now. 

Wayne Owens 912 832 6778


Thanks,
Robin
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