Today's Message Index:
----------------------
1. 11:56 AM - Re: 2010 Holiday trip (BlueSkyFlier)
2. 12:23 PM - Re: CATTO 3 bladed prop (BlueSkyFlier)
3. 12:40 PM - Re: Maneuvering Speed SAIB (BlueSkyFlier)
4. 03:36 PM - Re: Re: CATTO 3 bladed prop (Scott Stearns)
5. 04:10 PM - Re: Re: CATTO 3 bladed prop (Scott Stearns)
6. 04:41 PM - Re: Re: CATTO 3 bladed prop (Galin Hernandez)
7. 05:42 PM - Re: Re: CATTO 3 bladed prop (Robert Reed)
8. 08:12 PM - Re: Re: Maneuvering Speed SAIB (Flyinisfun@aol.com)
Message 1
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| Subject: | Re: 2010 Holiday trip |
Hi John (Petrie)
A belted answer to your question regarding the Henshaw challenge ...
I know all about it and followed the last two attempts closely. Not my idea of
enjoyable (or safe) flying - as the latest attempt illustrated. I believe the
Glassair is still sitting in Windhoek (which happens to be my home town :o))
My KIS has only 130hp at ground level, so not much of a chance to compete for the
record anyway. I'll just make my way down to Cape Town at my leisure. If I
add extra fuel tanks I can do 1000nm at a stretch. That will make for five stops
for the plane - maybe more for me :o).
Not yet made up my mind as to whether adding the extra tanks is worth the trouble.
Depends on how easy or difficult I find it to find Avgas when arranging with
FBOs for stopovers.
Have you decided on what your next plane will be after selling the KIS?
Regards,
Alfred
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| Subject: | Re: CATTO 3 bladed prop |
Hi Galin,
As part of making a decision about my new propeller (and also because I wanted
to do it) I created an performance model for the KIS which integrates propleller
and airframe models.
To my surprise and contrary to popular wisdom the results showed that
(a) larger diameter is not necessarily always better and
(b) 3 bladed props are rarely (if ever) better than 2 bladed props
At normal operating RPMs the parasitic drag of the third blade easily negates the
reduction in induced drag due to lower power loading per blade. So I would
suggest staying with a two blade prop unless ground clearance issues makes 3 blades
an unavoidable necessity.
For any particular density altitude and RPM, there is an optimum prop diameter
which maximises residual engine power across the speed range.
The diameter determines the prop blade power loading which in turn determines the
prop drag losses. Therefore, optimising diameter is equivalent to optimising
prop drag losses across the speed range for chosen RPM and altitude.
These non-linear characteristics of the propulsion system only become apparent
when the airframe and propeller are integrated together.
Regards,
Alfred
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| Subject: | Re: Maneuvering Speed SAIB |
Agreed Sott.
All moment arms come into play - that's why weight distribution (weight as a force)
is so important. With the big 360 up front you know about that.
Bottom line - slow down when the air gets turbulent, and then slow down even more
if airframe weight distribution is not as good as it could be.
Regards,
Alfred
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| Subject: | Re: CATTO 3 bladed prop |
I remember when the 'new' cessna 182 came out.- The 3 bladed propeller wa
s an option.- The POH showed no difference in performance between the two
and three bladed propellers, except the 3 bladed propeller was 40 pounds h
eavier and a $10,000+ option.- I've never seen a new 182 with a two blade
d propeller and a lot of older 182 have converted to three bladed props.-
It does look cool....
-
Scott
--- On Fri, 2/18/11, BlueSkyFlier <bleuskyfly@teledynamix.com> wrote:
From: BlueSkyFlier <bleuskyfly@teledynamix.com>
Subject: KIS-List: Re: CATTO 3 bladed prop
Hi Galin,
As part of making a decision about my new propeller (and also because I wan
ted to do it) I created an performance model for the KIS which integrates p
ropleller and airframe models.
To my surprise and contrary to popular wisdom the results showed that
(a) larger diameter is not necessarily always better and
(b) 3 bladed props are rarely (if ever) better than 2 bladed props
At normal operating RPMs the parasitic drag of the third blade easily negat
es the reduction in induced drag due to lower power loading per blade. So I
would suggest staying with a two blade prop unless ground clearance issues
makes 3 blades an unavoidable necessity.
For any particular density altitude and RPM, there is an optimum prop diame
ter which maximises residual engine power across the speed range.
The diameter determines the prop blade power loading which in turn determin
es the prop drag losses. Therefore, optimising diameter is equivalent to op
timising prop drag losses across the speed range for chosen RPM and altitud
e.
These non-linear characteristics of the propulsion system only become appar
ent when the airframe and propeller are integrated together.
Regards,
- - - - - - Alfred
--------
_________________________________________
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=331443#331443
le, List Admin.
=0A=0A=0A
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| Subject: | Re: CATTO 3 bladed prop |
Also,-a one bladed propeller is really best, just a bit hard to do.- So
me model racing airplanes use one bladed propellers with a counter weight t
o balance the prop.
-
Scott
--- On Fri, 2/18/11, BlueSkyFlier <bleuskyfly@teledynamix.com> wrote:
From: BlueSkyFlier <bleuskyfly@teledynamix.com>
Subject: KIS-List: Re: CATTO 3 bladed prop
Hi Galin,
As part of making a decision about my new propeller (and also because I wan
ted to do it) I created an performance model for the KIS which integrates p
ropleller and airframe models.
To my surprise and contrary to popular wisdom the results showed that
(a) larger diameter is not necessarily always better and
(b) 3 bladed props are rarely (if ever) better than 2 bladed props
At normal operating RPMs the parasitic drag of the third blade easily negat
es the reduction in induced drag due to lower power loading per blade. So I
would suggest staying with a two blade prop unless ground clearance issues
makes 3 blades an unavoidable necessity.
For any particular density altitude and RPM, there is an optimum prop diame
ter which maximises residual engine power across the speed range.
The diameter determines the prop blade power loading which in turn determin
es the prop drag losses. Therefore, optimising diameter is equivalent to op
timising prop drag losses across the speed range for chosen RPM and altitud
e.
These non-linear characteristics of the propulsion system only become appar
ent when the airframe and propeller are integrated together.
Regards,
- - - - - - Alfred
--------
_________________________________________
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=331443#331443
le, List Admin.
=0A=0A=0A
Message 6
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| Subject: | Re: CATTO 3 bladed prop |
Yes, I am aware of what you pointed out about the different props. But, I
want to use a smaller diameter prop since I fly in and out of runways that
are not very well kept. I have a constant struggle with nicks on my 76"
prop. I installed prop guard on the leading edge. It lessened the problem,
but it still exists more than I like.
That is why I wanted a PIREP if anybody had a CATTO prop and how it
performed.
Galin
On Fri, Feb 18, 2011 at 2:21 PM, BlueSkyFlier <bleuskyfly@teledynamix.com>wrote:
> >
>
> Hi Galin,
>
> As part of making a decision about my new propeller (and also because I
> wanted to do it) I created an performance model for the KIS which integrates
> propleller and airframe models.
>
> To my surprise and contrary to popular wisdom the results showed that
> (a) larger diameter is not necessarily always better and
> (b) 3 bladed props are rarely (if ever) better than 2 bladed props
>
> At normal operating RPMs the parasitic drag of the third blade easily
> negates the reduction in induced drag due to lower power loading per blade.
> So I would suggest staying with a two blade prop unless ground clearance
> issues makes 3 blades an unavoidable necessity.
>
> For any particular density altitude and RPM, there is an optimum prop
> diameter which maximises residual engine power across the speed range.
> The diameter determines the prop blade power loading which in turn
> determines the prop drag losses. Therefore, optimising diameter is
> equivalent to optimising prop drag losses across the speed range for chosen
> RPM and altitude.
>
> These non-linear characteristics of the propulsion system only become
> apparent when the airframe and propeller are integrated together.
>
> Regards,
> Alfred
>
> --------
> _________________________________________
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=331443#331443
>
>
Message 7
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| Subject: | Re: CATTO 3 bladed prop |
Well, there is one thing you won't have to worry about with the Catto 3 blad
ed is any significant weight increase. It is a very light prop. I know all
the issues of 2 vs. 3 but my main reason for the Catto 3 blade was the quie
t operation of the 3 bladed prop. My wife has migranes and I have made seve
ral changes to reduce cabin noise. Besides, it's one of the sexiest looking
props around.
Bob
Sent from my iPhone
On Feb 18, 2011, at 5:25 PM, Scott Stearns <sstearns2@yahoo.com> wrote:
> I remember when the 'new' cessna 182 came out. The 3 bladed propeller was
an option. The POH showed no difference in performance between the two and
three bladed propellers, except the 3 bladed propeller was 40 pounds heavie
r and a $10,000+ option. I've never seen a new 182 with a two bladed propel
ler and a lot of older 182 have converted to three bladed props. It does lo
ok cool....
>
> Scott
>
> --- On Fri, 2/18/11, BlueSkyFlier <bleuskyfly@teledynamix.com> wrote:
>
> From: BlueSkyFlier <bleuskyfly@teledynamix.com>
> Subject: KIS-List: Re: CATTO 3 bladed prop
> To: kis-list@matronics.com
> Date: Friday, February 18, 2011, 12:21 PM
>
>
>
> Hi Galin,
>
> As part of making a decision about my new propeller (and also because I wa
nted to do it) I created an performance model for the KIS which integrates p
ropleller and airframe models.
>
> To my surprise and contrary to popular wisdom the results showed that
> (a) larger diameter is not necessarily always better and
> (b) 3 bladed props are rarely (if ever) better than 2 bladed props
>
> At normal operating RPMs the parasitic drag of the third blade easily nega
tes the reduction in induced drag due to lower power loading per blade. So I
would suggest staying with a two blade prop unless ground clearance issues m
akes 3 blades an unavoidable necessity.
>
> For any particular density altitude and RPM, there is an optimum prop diam
eter which maximises residual engine power across the speed range.
> The diameter determines the prop blade power loading which in turn determi
nes the prop drag losses. Therefore, optimising diameter is equivalent to op
timising prop drag losses across the speed range for chosen RPM and altitude
.
>
> These non-linear characteristics of the propulsion system only become appa
rent when the airframe and propeller are integrated together.
>
> Regards,
> Alfred
>
> --------
> _________________________________________
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=331443#331443
>
>
> http://www.matronics.com/Nav - MATRONICS WEB
&nbsf="http://www.matronics.com/contribution" target=_blank>http://
www.matr====================
>
>
>
>
>
>
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Message 8
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| Subject: | Re: Maneuvering Speed SAIB |
Man do I ever know about maneuvering speed. I have the 0-320 Lyc. in my
two place and those little short wings just don't ride the bumps very well.
I have hit rough air and cracked my head on the ceiling several times
before I could get it slowed down. I have tested my wings several times trying
to run my engine wide open and couldn't shut it down fast enough. I can
indicate 180 mph full throttle and I believe that is about the limit I want
to see. Is anybody else consisently doing more?
Jesse
Agreed Sott.
All moment arms come into play - that's why weight distribution (weight as
a force) is so important. With the big 360 up front you know about that.
Bottom line - slow down when the air gets turbulent, and then slow down
even more if airframe weight distribution is not as good as it could be.
Regards,
Alfred
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