A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Home Built
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

IVO pireps wanted.. high performance/high speed...



 
 
Thread Tools Display Modes
  #1  
Old May 31st 04, 04:26 PM
Dave S
external usenet poster
 
Posts: n/a
Default IVO pireps wanted.. high performance/high speed...

Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.

What has been your experience with this product.. Any pro's or cons
based on your experience...

Has the product met your expectations...

Where I am coming from: working with a builder making a Mazda powered
Velocity. We have kicked around the idea of a controllable
pitch/quasi-constant speed propeller.

I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a
flying RV-4 with a Mazda rotary. His experience was that he had a loss
of top end speed with the IVO product compared to a fixed pitch prop...
It was enough of a difference that he has chosen not to research using
the product any further in his later applications. I am not sure if this
is because the blades are unable to "twist" enough or what.

This is somewhat disheartening, because the IVO seemed like a cost
effective possibility. The electric MT is out of my price range, and I
cant seem to find any other electric actuated in-flight adjustable props
that can handle 200-250 hp.

I am curious if others have experienced similar outcomes using this
propeller in applications running in the 170-200 kt/200-250 hp range

Dave

  #2  
Old May 31st 04, 08:09 PM
Jan Carlsson
external usenet poster
 
Posts: n/a
Default

Dave and everyone interested,

First I have to say that I have no experience what so ever with the IVO,
(but other props.)

I got this info from a builder in US on the IVO

3 blade, 66" dia prop, electric adjustable pitch from 45" to 105"

Max blade width: 5.25"
At 25" radius: 0.7" thickness, 4.75" width.

Analyze:

The blade thickness of almost 15% at the 0,75 radius is maybe one reason for
the reported result of the IVO to be less then others tested.

"Normal" or often used on wood props is 13% thickness; normal range is from
11% to 14% for wood props.

Metal props from 8,5% to 10%

Max blade width of 16% of the radius (33") is normal (15%-16.7%)

The blade width of 14,4% at the 0,75% radii is a bit wider then normal
(12-13%)

The adjustable pitch range from 45" to 105" (16deg to 34deg at 0,75% radii)
is good.

But it is only the outer parts of the blade that is changed in pitch not the
inner. What the pitch is here I don't know.

What effect does this have?

If we think of an adjustable prop (70" dia) that have CONSTANT PITCH along
the blade when the .75% radii is sat to 15deg. = 44" pitch

At the .45% radii the angle is 24deg.

(At the tip it is 11.3deg)

IF we now increase the angle of the whole blade 15deg to 30deg at the .75%
radii we get 95" pitch.

At the .45% radii =39deg = 80" pitch

(At the tip 26,3deg = 108,7")

This means that the inner parts of the propeller blade will not increase as
much as the outer parts in pitch, but this is not all bad, by a number of
reasons.

But if as in the case of IVO the inner part is not changed in pitch, it will
be far from optimum in some stage of the speed range. Especially if the
speed range is large as in high performance aircraft.

If the inner part is coarse pitch and fixed it will stall during take off
and climb.

If the inner part is fine pitched and fixed it will make negative thrust at
high speed.

So, The thicker and wider outer 25% of the blade aren't very effective, the
inner fixed pitch isn't good at all speeds!

A propeller that have blades that is thicker and wider then normal needs to
compensate this by reducing something else, like diameter and or blade area
to handle the same power, the pitch should be sat so the blade work at its
best L/D for efficiency, so if we reduce the pitch (angle of attack) to
compensate for an propeller that have to much drag it is not so good, it is
better to reduce the diameter in that case.

A thinner propeller is better (obvious) that will give us a larger diameter
that moves more air, or if the diameter is limited by tip-speed or
structural reasons, more blade area (more blades)



For now,

Jan Carlsson

www.jcpropellerdesign.com




"Dave S" skrev i meddelandet
hlink.net...
Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.

What has been your experience with this product.. Any pro's or cons
based on your experience...

Has the product met your expectations...

Where I am coming from: working with a builder making a Mazda powered
Velocity. We have kicked around the idea of a controllable
pitch/quasi-constant speed propeller.

I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a
flying RV-4 with a Mazda rotary. His experience was that he had a loss
of top end speed with the IVO product compared to a fixed pitch prop...
It was enough of a difference that he has chosen not to research using
the product any further in his later applications. I am not sure if this
is because the blades are unable to "twist" enough or what.

This is somewhat disheartening, because the IVO seemed like a cost
effective possibility. The electric MT is out of my price range, and I
cant seem to find any other electric actuated in-flight adjustable props
that can handle 200-250 hp.

I am curious if others have experienced similar outcomes using this
propeller in applications running in the 170-200 kt/200-250 hp range

Dave



  #3  
Old June 1st 04, 08:47 AM
Ken Sandyeggo
external usenet poster
 
Posts: n/a
Default

Might try NSI

http://www.nsiaero.com/nsiaero2/3.0/....7/3.3.1.7.htm



Dave S wrote in message thlink.net...
Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.

What has been your experience with this product.. Any pro's or cons
based on your experience...

Has the product met your expectations...

Where I am coming from: working with a builder making a Mazda powered
Velocity. We have kicked around the idea of a controllable
pitch/quasi-constant speed propeller.

I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a
flying RV-4 with a Mazda rotary. His experience was that he had a loss
of top end speed with the IVO product compared to a fixed pitch prop...
It was enough of a difference that he has chosen not to research using
the product any further in his later applications. I am not sure if this
is because the blades are unable to "twist" enough or what.

This is somewhat disheartening, because the IVO seemed like a cost
effective possibility. The electric MT is out of my price range, and I
cant seem to find any other electric actuated in-flight adjustable props
that can handle 200-250 hp.

I am curious if others have experienced similar outcomes using this
propeller in applications running in the 170-200 kt/200-250 hp range

Dave

  #6  
Old June 1st 04, 10:33 PM
Jan Carlsson
external usenet poster
 
Posts: n/a
Default

You have to make the research, don't you? Just ask them what they can do for
you, I am sure they want to show their best products.

I for sure would not put my money on an untested design just because it is
cheep, better to be able to come home for dinner.

Jan Carlsson


"Dave S" skrev i meddelandet
link.net...
And how many of those make electric controllable props that can handle
200-250 hp?

Jan Carlsson wrote:
Some Prop makers,

http://pro.wanadoo.fr/arplast/

http://www.aviapropeller.com/

http://www.bolly.com.au/

http://climbandcruise.com/

http://www.vzlu.cz/vrtule/basis.htm

http://www.gt-propellers.com/

http://www.hoffmann-prop.com/

http://www.mt-propeller.com/en/index.htm

http://www.sensenichprop.com/

http://www.nsiaero.com/index_yes.html

http://www.powerfin.com/

http://www.princeaircraft.com/

http://home.t-online.de/home/3200301.../rospeller.htm

http://whirlwindpropellers.com/

http://www.woodcomp.cz/

http://www.airmasterpropellers.com/

http://www.greatplainsas.com/ed.html

http://www.jcpropellerdesign.com/

Jan Carlsson





  #7  
Old June 1st 04, 10:36 PM
Dave S
external usenet poster
 
Posts: n/a
Default

thanks Ken

Ken Sandyeggo wrote:

Might try NSI

http://www.nsiaero.com/nsiaero2/3.0/....7/3.3.1.7.htm



Dave S wrote in message thlink.net...

Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.

What has been your experience with this product.. Any pro's or cons
based on your experience...

Has the product met your expectations...

Where I am coming from: working with a builder making a Mazda powered
Velocity. We have kicked around the idea of a controllable
pitch/quasi-constant speed propeller.

I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a
flying RV-4 with a Mazda rotary. His experience was that he had a loss
of top end speed with the IVO product compared to a fixed pitch prop...
It was enough of a difference that he has chosen not to research using
the product any further in his later applications. I am not sure if this
is because the blades are unable to "twist" enough or what.

This is somewhat disheartening, because the IVO seemed like a cost
effective possibility. The electric MT is out of my price range, and I
cant seem to find any other electric actuated in-flight adjustable props
that can handle 200-250 hp.

I am curious if others have experienced similar outcomes using this
propeller in applications running in the 170-200 kt/200-250 hp range

Dave


  #8  
Old June 2nd 04, 04:58 AM
Paul Lee
external usenet poster
 
Posts: n/a
Default

Dave S wrote in message thlink.net...
Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.


Dave,

I have an IVO prop with a 220hp Franklin. But am just starting testing
phase and have not tested the high end.

But you should be aware that IVO makes two pitch ranges for their
magnum props: [30"- 90"] and [45" to 105"]. I have the higher pitch
range prop whose average pitch is greater than the pitch recommended
for my aircraft with fixed pitch props and should be expected to do
better at higher end. Somebody getting the lower pitch range can
expect good takeoff performance but probably average cruise.

I don't think that IVO is a perfect substitute for the expensive
constant speed props, but is a lot better than a fixed pitch and
may be satisfactory for your needs if you select the right pitch
range - and is a very decent price to boot.

-----------------------------------------
Paul Lee, SQ2000 canard: www.abri.com/sq2000
  #9  
Old June 2nd 04, 04:12 PM
Bashir
external usenet poster
 
Posts: n/a
Default

Dave S wrote in message thlink.net...
Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props.

What has been your experience with this product.. Any pro's or cons
based on your experience...

Has the product met your expectations...

Where I am coming from: working with a builder making a Mazda powered
Velocity. We have kicked around the idea of a controllable
pitch/quasi-constant speed propeller.

I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a
flying RV-4 with a Mazda rotary. His experience was that he had a loss
of top end speed with the IVO product compared to a fixed pitch prop...
It was enough of a difference that he has chosen not to research using
the product any further in his later applications. I am not sure if this
is because the blades are unable to "twist" enough or what.

This is somewhat disheartening, because the IVO seemed like a cost
effective possibility. The electric MT is out of my price range, and I
cant seem to find any other electric actuated in-flight adjustable props
that can handle 200-250 hp.

I am curious if others have experienced similar outcomes using this
propeller in applications running in the 170-200 kt/200-250 hp range

Dave


This came over the Velocity mailing list --

=============================================

Carbureted/magneto Franklin, electric IVO.
Nothing special.

I wanted to get more data, but clouds below 5000 was a problem.

The best speed we saw was at 7500 feet altitude, full throttle, the first
altitude where we actually
achieved full open throttle.
182KTS TAS, 2520 RPM, 23.1 inches MAP, 12.4GPH.

I was more impressed however, with putting more pitch in the prop. At this
same altitude, I took data at progressively slower RPM's (same throttle).
174KTS TAS, 2300 RPM, 23.5 inches MAP, 10.8GPH.

We stabilized a climb through 8000 feet at 120 kts indicated, 144kts true at
700FPM rate.

Levelling at 9000, going through various MAP/RPM settings, I was impressed
by the economies achieved:
KTS TAS RPM MAP GPH
1 147 2370 19.7 9.5
2 180 2520 21.8 12
3 175 2400 21.9 11.2
4 162 2200 22.1 9.9

At line 1, this is at 120 kts indicated (where I started data collection),
147TAS. This is partial throttle operation. Not bad for 9.5GPH, but look
at line 4, full throttle, slower RPM. Faster speed, with just a little more
fuel flow. I find it surprising that pumping losses account for a 5%
penalty between lines 1 and 4. That's 15.5 nautical miles/gal and 16.4
nautical miles/gal for lines 1 and 4.

The most economical was at 7500 feet:
174KTS TAS 2300RPM 23.5MAP 10.8GPH, making that 16.1 nm/gallon. I don't
know why I didn't get at data point at 2200RPM. It would have been better
yet.
What this says to me is pick a MAP/RPM combo that is the economy setting you
want, then fly the altitude that will give you that power setting at WOT.

It was hot too. 95F on the ground, adding about 3000' for density altitude.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 09:48 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AviationBanter.
The comments are property of their posters.