REFLECTOR: Ivo and Vesta

[Andy Millin]

Hey Larry,

 

Believe it or not, I did a fair amount of research on the Ivo.  I wanted to
use the Ivo.  I gave the guy a call and we spoke for nearly an hour.

 

Way back in the day Mark Machado had mounted an Ivo on a standard with an
IO-360.  He was VERY impressed with the performance.   I believe the write
up was in Velocity Views.  It sounded like it was going to be better than
sliced bread AND peanut butter.  It is a real performer, great price, etc.

 

Ivo's blades are very light.  The prop is amazingly light.  This is a
blessing and a curse.  The prop does not have enough mass to absorb the
significant torque thrashing a big bore aircraft engine produces.  In his
own words "you could see the prop was just being tortured."  At low RPM it
was possible to see the blades flexing length wise as the amazing shear
forces were hitting the base.

 

The blades are tough and as far as I know they never failed.  What did
happen was the blades would shift at the base.  They would work their way
free from the bolts.  Ivo compensated with a very specific torquing regimen
combined with stainless steel foil marking tape on the seams.  I believe
this worked.  However . not all users of the prop were as vigilant or
patient as they needed to be.

 

I believe Ivo called for torque the bolts, run the engine, re-torque the
bolts, re-run the engine, repeat until the torque does not change between
cycles.

 

In 1997, Mark Ewart and his family were killed  (Standard Velocity DMO-266).
Please read the report yourself: http://tinyurl.com/dhok3m   It was RELATED
to the Ivo.  The detail related to the Prop is on the second page.  Reading
the whole report is better.

 

In the end Ivo decided to stop fighting with big bore aircraft engines and
their violent torque curves.  His props really can withstand 750 HP, you
just have to have a relatively smooth power curve.  Ivo has been a very good
option for guys like Chris Barber running a rotary with reduction unit.
Smooth.

 

It works on the Franklin as a 6 cylinder 360 has smoother power curve than 4
cylinder 360.

 

As for the Vesta.  If you want to read back in the Archives, I was one of
the first, possibly even the first from the Velocity community to speak with
Jason Day.  Jason is a very nice guy.  I had acted as a bit of a liaison to
get him to work with Velocity to develop a prop for us and have Velocity
test the thing.

 

A major portion of Jason's business is automotive conversions for aircraft.
His props have been running by-and-large on automotive engines with
reduction units on them - read smooth power curve.

 

Jason's stuff looks great.  I believe he has the background and skills to
make a great prop.  Problem is, he didn't have ANY experience with our prop
running on an aircraft engine.  Velocity wanted to help, but were unwilling
to risk Turbo Charlie $200K+ aircraft and a pilot on a completely untested
prop.

 

Velocity suggested that Jason give the prop to testers in the Airboat
industry and let them beat on it for a year.  I don't believe Jason was
willing and I'm pretty sure this has never been done.

 

Bob Buls owns one of Jason's props.  Bob is also going to run it with one of
Jason's automotive conversions.

 

Dave Dent has a prop and has been working with Jason on it.  I sincerely
wish Dave the best of luck on his flight testing and am eager to hear his
findings.  This could be a great new option for us.

 

The other concern on the Vesta is the weight.  It is a heavy prop.  I
believe it might weigh 50 to 100% more than the MT or Aero Composite.

 

Please form your own opinions based on your own direct research.  For my
soft pink body, I'll wait for someone else to strap one on and hit the wild
blue.

 

Andy

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