REFLECTOR: Ivo and Vesta

Thu Apr 23 12:54:35 CDT 2009

Andy thanks for the testing encouragement.  I will let you all know how it goes.  I have test flown a number of planes and modifications on planes.  So far the first blades that came on Vesta props were like trying to fly a Clark Y wing at supersonic speeds, it don't work.  Now the blades can meet those speeds.  The airfoil is much better.  
Before I install it again I will do a weight test on the MT/Vesta. I have electronic scales so it will be right for sure. When I changed it out before I did weigh them but right now I don't remember the numbers.  They may be in the log book when I test flew it the first time. I know I saw no difference in flight handling.  
Dave
  ----- Original Message ----- 
  From: Andy Millin 
  To: 'Velocity Aircraft Owners and Builders list' 
  Sent: Thursday, April 23, 2009 5:27 AM
  Subject: REFLECTOR: Ivo and Vesta

  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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