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IVO first flight

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Kayberg(at)AOL.COM
Guest

Posted: Thu Nov 13, 2008 1:56 pm Post subject: IVO first flight

Dateline Green Landings from the Chief Hangar Rat:

  

 Along with a Lighning First Flight this past week, there has also been an  IVO first flight.

  

 One of our intrepid owners replaced his adjustable Sensinich prop with a  three-blade IVO Magnum with In- flight adjust.

  

 Very very preliminary testing indicates a normal take off and climb (but  that will be tweaked) but a faster top speed.   The numbers are rough  since it was only a couple short flights,  but it looks like a top of 175  at low altitude is easily achieved.  Other virtues indicate that one can  set the fuel flow and then set the prop pitch to match.   The braking  effect of a three blade on final is also helpful to increasing the  approach angle of a long wing.

  

 Weather will prevent much more data for a while.   I would not  encourage anyone to run right out and buy an IVO inflight adjust.  The avid  experimenter above has many years of experience with this prop on a Rotax  912-S.  However, for those who want the very max speed and efficiency the  IVO may offer something. 

  

 My personal observation is that while fixed pitch props are simple, they  are hard to match to a plane.   "Musical Props" is the game that seems  to be played frequently.   There is simply a lot of difference between  builds (long wing, short wing , rigging, wheel pants fit, etc) and  engine power.  We find some engines have more power out of the box and some  have less.   We also find that the props, possibly because they are  wood, also vary significantly....and Sensenich has a long lead time.    

  

 We can get IVO props overnight if necessary.  If you have some kind of  prop strike, the IVO easily  disintegrates, usually saving the engine  crankshaft.   Supposedly it is good for up to 150 hp and 250  mph.  We shall see.

  

 So just consider this a heads-up.

  

 Doug

  [quote][b]

N1BZRich(at)aol.com
Guest

Posted: Thu Nov 13, 2008 6:22 pm Post subject: IVO first flight

In a message dated 11/13/2008 4:57:14 P.M. Eastern Standard Time,  Kayberg(at)AOL.COM writes:

  	  Quote: 	
		  but it    looks like a top of 175 at low altitude is easily  achieved. 	


 

 Doug,

     How about some clarification of what you mean by "a  top of 175".  Is that MHP or Knots?  And what is "low altitude"?   And since you said low altitude, I assume you are talking indicated  airspeed.  Are we talking wide open throttle?  And are we talking  about a "pass down the runway" (I seem to remember you guys are about 500  AGL)?  And if so, what was the rpm at WOT?  Were you able to adjust  the pitch in flight to get the engine to be WOT at 3300 rpm?

     With the fixed pitch I am now using I can see just  over 200 MPH (pulling back the throttle to keep from going over 3300 rpm) on a  high speed pass down the runway, but remember I am basically at sea  level.   At 5000', (again pulling back the throttle to stay  at 3300) it shows 185 to 187 MPH true.    

     Also what is the going price for the in-flight  adjustable IVO?  Does it still have those narrow cord blades?  

     How is the Cub project coming along?   And remember, you are invited to come here to fly my Cub.

 Blue Skies,

 Buz



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  [quote][b]

Kayberg(at)AOL.COM
Guest

Posted: Fri Nov 14, 2008 7:04 am Post subject: IVO first flight

Sorry, but I gotta be a little fuzzy on the details.  It was just two  short flights by two different people.  The airspeed had just been changed  because it "indicated a little low"  but the new one "indicates a little  high".   The speed runs were in level flight but the optimum prop  settings had not be reached.  175 mph is perhaps the fastest this airframe  had gone...and it has had a couple of Sensnich props on it  before.   Altitude for the runs was about 1500 feet.   It  was a cool day, so probably close to sea level.

  

 The pitch adjust worked fine.  When you lowered the nose after the  climbout, the rpms went past 3300 easily and the pitch adjust dropped it to ????  .   Tweeking is needed because it would not turn more than 2350  static.  The owner is looking for more thrust on takeoff and more speed at  the top.  The consensus of the test pilots was, "that is the fastest that  airplane has ever gone"   ...both the level passes and the obligitory  dive to high speed down the runway were fast.

  

 I dont know the cost of the IVO, since that was not in my department, but  it is close to the cost of the ground adjust Senny.  More than a fixed  pitch, but not by a lot.

  

 the other thing was cooling.  Even with no spinner (fitting one will  be a bitch) it ran cooler than usual.   Of course it was a cool day,  but cooling seemed better.  The IVO has good pitch to the blades close to  the air inlets.

  

 Again, I would caution those out there in radio land to wait until  more testing is done.   And dont plan on it being real  scientific.  In my mind, we need to see how the prop stands the  pulses.   However, the consensus was that this is the smoothest prop  yet, so it cant all be bad.   the IVO needs to be retorqued ever hour  or so during the first 10 hours of running.  The blades "settle in" to the  grip on the hub plates and it is very important that those not get loose.

  

 There is some plan afoot to remove one blade and try it as a two blade  (easily done with an IVO)

  

 Keep in mind this project is assisted by the Green Landings technical  staff, but not under their direct control.[img]http://cdn-cf.aol.com/se/smi/0201d20638/02[/img]

  

  

 Doug

  

 In a message dated 11/13/2008 9:23:33 P.M. Eastern Standard Time,  N1BZRich(at)aol.com writes:

  	  Quote: 	
		     Doug,

       How about some clarification of what you mean by    "a top of 175".  Is that MHP or Knots?  And what is "low    altitude"?  And since you said low altitude, I assume you are talking    indicated airspeed.  Are we talking wide open throttle?  And are we    talking about a "pass down the runway" (I seem to remember you guys are about    500 AGL)?  And if so, what was the rpm at WOT?  Were you able to    adjust the pitch in flight to get the engine to be WOT at 3300 rpm?

       With the fixed pitch I am now using I can see    just over 200 MPH (pulling back the throttle to keep from going over 3300 rpm)    on a high speed pass down the runway, but remember I am basically at sea    level.   At 5000', (again pulling back the throttle to    stay at 3300) it shows 185 to 187 MPH true.    

       Also what is the going price for the in-flight    adjustable IVO?  Does it still have those narrow cord blades?   

       How is the Cub project coming along?     And remember, you are invited to come here to fly my Cub.

   Blue Skies,

   Buz



	


 

  

  [quote][b]

dashvii(at)hotmail.com
Guest

Posted: Fri Nov 14, 2008 3:44 pm Post subject: IVO first flight

Doug C

   Are there any pics of the IVO on the Lightning.  Also C when converting an IVO to a two blader C do you use the same blades: profile C pitch C and chord?  Brian W.

 From: Kayberg(at)aol.com

Date: Fri C 14 Nov 2008 10:03:07 -0500

Subject: Re: IVO first flight

To: lightning-list(at)matronics.com

  Sorry C but I gotta be a little fuzzy on the details.  It was just two short flights by two different people.  The airspeed had just been changed because it "indicated a little low"  but the new one "indicates a little high".   The speed runs were in level flight but the optimum prop settings had not be reached.  175 mph is perhaps the fastest this airframe had gone...and it has had a couple of Sensnich props on it before.   Altitude for the runs was about 1500 feet.   It was a cool day C so probably close to sea level.

 The pitch adjust worked fine.  When you lowered the nose after the climbout C the rpms went past 3300 easily and the pitch adjust dropped it to ???? .   Tweeking is needed because it would not turn more than 2350 static.  The owner is looking for more thrust on takeoff and more speed at the top.  The consensus of the test pilots was C "that is the fastest that airplane has ever gone"   ...both the level passes and the obligitory dive to high speed down the runway were fast.

 I dont know the cost of the IVO C since that was not in my department C but it is close to the cost of the ground adjust Senny.  More than a fixed pitch C but not by a lot.

 the other thing was cooling.  Even with no spinner (fitting one will be a bitch) it ran cooler than usual.   Of course it was a cool day C but cooling seemed better.  The IVO has good pitch to the blades close to the air inlets.

 Again C I would caution those out there in radio land to wait until more testing is done.   And dont plan on it being real scientific.  In my mind C we need to see how the prop stands the pulses.   However C the consensus was that this is the smoothest prop yet C so it cant all be bad.   the IVO needs to be retorqued ever hour or so during the first 10 hours of running.  The blades "settle in" to the grip on the hub plates and it is very important that those not get loose.

 There is some plan afoot to remove one blade and try it as a two blade (easily done with an IVO)

 Keep in mind this project is assisted by the Green Landings technical staff C but not under their direct control.[img]http://cdn-cf.aol.com/se/smi/0201d20638/02[/img]

 Doug

 In a message dated 11/13/2008 9:23:33 P.M. Eastern Standard Time C N1BZRich(at)aol.com writes:

  	  Quote: 	
		   Doug C

     How about some clarification of what you mean by "a top of 175".  Is that MHP or Knots?  And what is "low altitude"?  And since you said low altitude C I assume you are talking indicated airspeed.  Are we talking wide open throttle?  And are we talking about a "pass down the runway" (I seem to remember you guys are about 500 AGL)?  And if so C what was the rpm at WOT?  Were you able to adjust the pitch in flight to get the engine to be WOT at 3300 rpm?

     With the fixed pitch I am now using I can see just over 200 MPH (pulling back the throttle to keep from going over 3300 rpm) on a high speed pass down the runway C but remember I am basically at sea level.   At 5000' C (again pulling back the throttle to stay at 3300) it shows 185 to 187 MPH true.    

     Also what is the going price for the in-flight adjustable IVO?  Does it still have those narrow cord blades?  

     How is the Cub project coming along?  And remember C you are invited to come here to fly my Cub.

 Blue Skies C

 Buz

 	  Quote: 	

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st">http://www.matronics.com/Navigator?Lightning-List

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selwyn

Joined: 12 Mar 2008
Posts: 102
Location: Australia

Posted: Fri Nov 14, 2008 11:32 pm Post subject: Re: IVO first flight

"If you have some kind of prop strike, the IVO easily disintegrates, usually saving the engine crankshaft. Supposedly it is good for up to 150 hp and 250 mph. We shall see."



Hmmm.  Not sure if I like a prop that easily disintegrates as that would imply that the margins are rather fine and perhaps more likely to shed a blade in "normal" circumstances.  I think I would prefer some additional protection against that instead of the possibility that I may prevent crank damage if I was silly enough to run my prop into something hard.



If anyone is interested in more info I've compiled a list of links to prop makers, including IVO, here:

http://www.recreationalflying.com.au/links/propellers-4/

_________________
Cheers, Selwyn
Kit 66 VH-ELZ

jhausch

Joined: 14 Jan 2008
Posts: 35

Posted: Sat Nov 15, 2008 6:58 am Post subject: Re: IVO first flight

"Hmmm. Not sure if I like a prop that easily disintegrates as that would imply that the margins are rather fine "



Not sure I agree.  I would imagine the margins are acceptable when loaded as designed.  



The Osprey has rotor/prop blades which are designed to "broomstraw" if one must land with the nacelles in the horizontal position. 



The other idea which comes to mind is tempered glass.  Very strong when loaded as designed, very fragile when struck on edge.

N1BZRich(at)AOL.COM
Guest

Posted: Sat Nov 15, 2008 4:52 pm Post subject: IVO first flight

Unless IVO has changed their blade design, I doubt that their props will be  as efficient as the Sensenich models that have been so successful on the  Lightning.  The original IVO props were designed for the Rotax which of  course have a "gear down transmission" to reduce prop speed.  The slower  turning props can use a longer diameter and narrow blades.  It has been a  while since I took Aero 101, but I think the best propeller tip speed for  efficiency is about .75 mach.  Since the Jabiru is a direct drive  "airplane" engine, the prop rpm is the same as engine rpm and you have a more  "normal" looking prop and blade profile that works best.  Of course as  everyone knows making propellers is part science and part black magic, so  who really knows what will work best on a specific airframe and engine  combination until you try it.  So glad the Green Landing guys are trying it  again.  

 Buz



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  [quote][b]

Kayberg(at)AOL.COM
Guest

Posted: Sun Nov 16, 2008 5:08 am Post subject: IVO first flight

In a message dated 11/14/2008 6:45:22 P.M. Eastern Standard Time,  dashvii(at)hotmail.com writes:

  	  Quote: 	
		  Doug,

  Are there any pics of the IVO on the Lightning.     Also, when converting an IVO to a two blader, do you use the same blades:    profile, pitch, and chord?  Brian W.

	


 

  

 No pics just yet.  Need a little more time and weather.  Plus,  there is no spinner.  It was also necessary to change the prop extension  back to the stock shorter one.

  

 The IVO Medium blades are all the same.  They can vary in length,  the ones tested are 62".    Supposedly a 68" blade will work on a  Jab 3300 also.  

  

 Doug

  [quote][b]

Kayberg(at)AOL.COM
Guest

Posted: Sun Nov 16, 2008 5:24 am Post subject: IVO first flight

In a message dated 11/15/2008 2:33:26 A.M. Eastern Standard Time,  selwyn(at)ellisworks.com.au writes:

  	  Quote: 	
		  -->    Lightning-List message posted by: "selwyn"    <selwyn(at)ellisworks.com.au>



"If you have some kind of prop strike,    the IVO easily disintegrates, usually saving the engine crankshaft. Supposedly    it is good for up to 150 hp and 250 mph. We shall see."



Hmmm.  Not    sure if I like a prop that easily disintegrates as that would imply that the    margins are rather fine and perhaps more likely to shed a blade in "normal"    circumstances.  I think I would prefer some additional protection against    that instead of the possibility that I may prevent crank damage if I was silly    enough to run my prop into something hard.



If anyone is interested in    more info I've compiled a list of links to prop makers, including IVO,    here:

http://www.recreationalflying.com.au/links/propellers-4/



	


 

  

  

 The IVO props may not be for everyone.  Some people cannot deal with a  prop where the tips can flex as much as 12" or perhaps more.     They are also noisy.   

  

 Our experience is that they outperform anything else:  more thrust on  takeoff and higher top speeds...at least in other applications.  There are  tradeoffs.

  

 They do not like rain or seaplane operations. 

  

 If the hub is kept torqued correctly, they do not shed a blade under  "normal circumstances"   

  

 No question that a " wooden fence post" prop is less likely to shed a  blade.   It is also very difficult to adjust the pitch.

  

 doug

  [quote][b]

Kayberg(at)AOL.COM
Guest

Posted: Sun Nov 16, 2008 5:52 am Post subject: IVO first flight

In a message dated 11/15/2008 7:53:02 P.M. Eastern Standard Time,  N1BZRich(at)aol.com writes:

  	  Quote: 	
		     Unless IVO has changed their blade design, I doubt that their props will    be as efficient as the Sensenich models that have been so successful on the    Lightning.  The original IVO props were designed for the Rotax which of    course have a "gear down transmission" to reduce prop speed.  The slower    turning props can use a longer diameter and narrow blades.  It has been a    while since I took Aero 101, but I think the best propeller tip speed for    efficiency is about .75 mach.  Since the Jabiru is a direct drive    "airplane" engine, the prop rpm is the same as engine rpm and you have a more    "normal" looking prop and blade profile that works best.  Of course as    everyone knows making propellers is part science and part black magic, so    who really knows what will work best on a specific airframe and engine    combination until you try it.  So glad the Green Landing guys are trying    it again.  

   Buz



	


 

  

  

 I understand the theory; that the difference in prop tip speed will make  the IVO less efficient.   However, with a Rotax 912-s  we swing a  72" three blade.   The 3300 Jab has a 62" prop.   Perhaps  the IVO is optimised for the greater RPMs.

  

 We are talking about much thinner Kevlar blades on the IVO, rather the  wooden fence post of a Senny.  Even the composite blades of the ground  adjust Sennsenich  are much thicker than the IVO.

  

 Also the IVO blades are all the same.  Not true with a  wooden  prop.   Each prop is subject to some variation as moisture content  changes.   Uneven moisture retention can make for vibrations.

  

 The guru on the Tailwind site buys wooden props and then sands  the profile of the tips a bit to get more speed out of them.   His  planes outrun higher horsepower RV's.    However, he has  built 10 Tailwinds from scratch and has reshaped a lot of  props.    

  

 It seems that everyone who buys wooden props tends to accumulate a  selection of them.   That gets a little pricey after  while.   Once you have one of them hanging on the wall of your living  room and one hanging on your plane, the rest are as helpful as unused golf  clubs.

  

 Additiionally, the point of the IVO in question is to have in-flight  adjust.  There is even a constant-speed controller if you want one.   So blade profile may be less important.  

  

  

 doug

  [quote][b]

N1BZRich(at)aol.com
Guest

Posted: Sun Nov 16, 2008 6:20 am Post subject: IVO first flight

In a message dated 11/16/2008 8:52:58 A.M. Eastern Standard Time,  Kayberg(at)AOL.COM writes:

  	  Quote: 	
		  Uneven    moisture retention can make for vibrations. 	


 

 Doug,

     Excellent point, and a good  reminder  for wooden prop users..  That is why all wooden props should  always be left in the horizontal position when  the airplane is parked.  That way, the prop blades accumulate moisture at  the same rate or amount and you do not get an out of balance blade that would  indeed cause vibration on start up.

     Keep us informed on the IVO testing.  But I am  still curious as to the 175 mph speed you mentioned.  Was that WOT?   

 Blue Skies,

 Buz



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  [quote][b]

Kayberg(at)AOL.COM
Guest

Posted: Sun Nov 16, 2008 2:40 pm Post subject: IVO first flight

In a message dated 11/16/2008 9:20:51 A.M. Eastern Standard Time,  N1BZRich(at)aol.com writes:

  	  Quote: 	
		    Keep us informed on the IVO testing.  But I am still    curious as to the 175 mph speed you mentioned.  Was that WOT?     	


 

 As best I understood, it was WOT with the prop "bit in" , ie the blades  were adjusted to give  a less than 3300 rpm.    Because of  the shortness of the flight,  the uncertainty of the airspeed  indicator and limited experimentation, the number of 175 was  offered.    Again, this was the fastest the bird has seen at a  full power flat run.

  

 doug

  [quote][b]

selwyn

Joined: 12 Mar 2008
Posts: 102
Location: Australia

Posted: Mon Nov 17, 2008 12:50 am Post subject: Re: IVO first flight

Puts a whole new meaning to the term "glass prop" doesn't it.



But seriously, a prop has to be able to withstand some serious shock and vibration loadings in normal operation, more so on a direct drive engine such as the Jab than on a reduction drive such as the Rotax.  To design something to stand up to these loads yet still disintegrate on a prop strike sufficiently easily to avoid engine damage is an engineering challenge of a high order.



There have been enough instances of deciduous blades on composite props to indicate that not everyone has even the first part of the requirement under control.  Personally I would prefer that part to be right and I'll accept responsibility for keeping my prop away from hard things.



Don't get me wrong though, I would dearly love to have a variable pitch prop option for my Lightning so I will be very interested in the results of this trial and wishing everyone involved the best of luck.

 	  jhausch wrote: 	
		  "

Not sure I agree.  I would imagine the margins are acceptable when loaded as designed.  



The Osprey has rotor/prop blades which are designed to "broomstraw" if one must land with the nacelles in the horizontal position. 



The other idea which comes to mind is tempered glass.  Very strong when loaded as designed, very fragile when struck on edge.

_________________
Cheers, Selwyn
Kit 66 VH-ELZ

Kayberg(at)AOL.COM
Guest

Posted: Mon Nov 17, 2008 4:47 am Post subject: IVO first flight

In a message dated 11/17/2008 3:51:09 A.M. Eastern Standard Time,  selwyn(at)ellisworks.com.au writes:

  	  Quote: 	
		  

But    seriously, a prop has to be able to withstand some serious shock and vibration    loadings in normal operation, more so on a direct drive engine such as the Jab    than on a reduction drive such as the Rotax.  To design something to    stand up to these loads yet still disintegrate on a prop strike sufficiently    easily to avoid engine damage is an engineering challenge of a high    order.

	


 

  

 I dont think it was a part of the design criteria, just a byproduct.

  

 The blades are very thin at the end.  They need to be thin for the  metal rod inside them to be able to twist the blade.   This also makes  the prop have lower inertia.    Again, this is a very light  prop.   It flexes a lot.   

  

 I like the prop, but I remain a skeptic about the power pulses from the Jab  engine.   True they are smaller than a 4 cyl Lycoming  and at a  different frequency, but we just need to see how it lasts.   I am  aware of a failure on the Vernier engine.  That was a two-cyl 80 hp engine  that was geared, but it still wiped out a 3 blade IVO in about 10  hours.    IVO did not recommend that prop/engine  combination.   They are fine with the Jab 3300/IVO Magnum.

  

 The incidence of prop strikes in Experimental Aircraft is high.  If  you have a constant speed prop and a Lycoming engine on your Vans project,   taxing into a gopher hole can cost you $15,000 or more in just a  second.    Taxing a Lightning with an IVO into the same hole  could cost about $450.     Something to think about.

  

 doug

  [quote][b]

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