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Dana

Joined: 13 Dec 2007 Posts: 1047 Location: Connecticut, USA
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Posted: Wed Jul 15, 2009 9:56 am Post subject: Victor 1+ Report |
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At 09:20 AM 7/15/2009, Jack B. Hart wrote:
Quote: |
I do not subscribe to the cork screw prop wash theory. I do subscribe to
the adverse roll caused by the torque reaction between the propeller and the
aircraft. This is countered with a little ailerons bias which then causes
the adverse yaw.
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The spiraling slipstream is definitely a factor in turning tendencies under
power. On a conventional (tractor) aircraft this force operates in the
same direction as the P-factor and torque, while on a high mounted pusher
like a Kolb it counteracts the P-factor and torque, since the bottom half
of the spiraling slipstream is hitting the fin instead of the upper
half. Which is stronger I can't say, but certainly it's going to be
stronger the closer the prop is to the vertical fin.
P-factor should not be an issue in cruise if the engine is set up properly
(thrust line parallel to the relative wind).
At 09:56 AM 7/15/2009, lucien wrote:
Quote: |
...my FSII... needed left rudder on the takeoff roll...
So judging by that, it couldn't have been P-factor or torque but something
else stronger than either of those affects. Well, my guess anyway. There
was no offset in the engine mounting, the crank was parallel to the
tailboom.....
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Is that the way it's supposed to be? I was under the impression that the
low boom Kolbs had the boom tube angled upwards from the pod in level
flight, so if the thrust line was parallel to the boom you'd get P-factor
in the opposite direction, i.e. a RH turning prop would then cause a right
turning tendency.
-Dana
--
New safety announcement from the Department of Homeland
Security: Securely duct tape shut any books you may own about civil
liberties or the U.S. Constitution.
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Dana

Joined: 13 Dec 2007 Posts: 1047 Location: Connecticut, USA
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Posted: Wed Jul 15, 2009 10:19 am Post subject: Victor 1+ Report |
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At 11:33 AM 7/15/2009, Ron (at) KFHU wrote:
Quote: | ...The Kolb thrust line is pretty close to its center of mass so its
moment arm for affecting deviation from flight path is pretty weak, as
compared to a Cessna 150...
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No, the effect of P-factor is a torque around the yaw axis, and a torque
("couple" in engineering terms) is independent of location.
However, P-factor is a factor of the relative wind, and there are two
things on a Kolb that would tend to reduce it. First, the low speed means
that the propeller induced inflow (air is "sucked" into the prop) is a
larger factor, tending to align the airflow with the thrust line before it
even gets to the prop. Second, the location of the prop behind the wing
means that it's operating in the wing induced downflow rather than the free
stream direction. This latter could cause a P-factor in either direction
depending on the thrust line and the direction of the downflow vector.
-Dana
--
New safety announcement from the Department of Homeland
Security: Securely duct tape shut any books you may own about civil
liberties or the U.S. Constitution.
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captainron1(at)cox.net Guest
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Posted: Wed Jul 15, 2009 11:51 am Post subject: Victor 1+ Report |
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You should not start a post with a "no", as that indicates rudeness or belligerence, if you must say no you need to enter it after you made you counter point or made your explanation.
P-Factor is short for propeller factor Dana, in other words the entire effect of the propeller from induced drag to counter torque is at play, so if you do not want to come across as an ignorant jerk trying to raise yourself to a level of expertise that you have yet to show, you need to word your answers quite differently.
Having said that now let me read the rest of your post, and see if there is anything worth considering in it.
Okay I read the rest of your message and I am not seeing where your Jerk Off "No" is coming from.
So post your explanation as to what exactly your " jerk off " no is about.
You may be one of those jack asses where being civil to you indicates a weakness, I run into people like that every so often and after I get over their * rudeness * I respond to them in the manner that they understand and deserve, so thread carefully especially if you don't know who you are talking to Dana. Trust me when I say to you that I am way better than you at flaming, so if you choose to be uncivil not only will you disturb this entire list but also come out on the short end of the stick.
Ron (at) KFHU
============================
---- Dana Hague <d-m-hague(at)comcast.net> wrote:
=============
At 11:33 AM 7/15/2009, Ron (at) KFHU wrote:
Quote: | ...The Kolb thrust line is pretty close to its center of mass so its
moment arm for affecting deviation from flight path is pretty weak, as
compared to a Cessna 150...
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No, the effect of P-factor is a torque around the yaw axis, and a torque
("couple" in engineering terms) is independent of location.
However, P-factor is a factor of the relative wind, and there are two
things on a Kolb that would tend to reduce it. First, the low speed means
that the propeller induced inflow (air is "sucked" into the prop) is a
larger factor, tending to align the airflow with the thrust line before it
even gets to the prop. Second, the location of the prop behind the wing
means that it's operating in the wing induced downflow rather than the free
stream direction. This latter could cause a P-factor in either direction
depending on the thrust line and the direction of the downflow vector.
-Dana
--
New safety announcement from the Department of Homeland
Security: Securely duct tape shut any books you may own about civil
liberties or the U.S. Constitution.
--
kugelair.com
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aslsa.rng(at)gmail.com Guest
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Posted: Wed Jul 15, 2009 12:04 pm Post subject: Victor 1+ Report |
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Ah, another fan you've made, Dana. Congratulations, that Dale Carnegie course is working just fine.
Rick Girard
do not archive
On Wed, Jul 15, 2009 at 2:50 PM, Ron (at) KFHU <captainron1(at)cox.net (captainron1(at)cox.net)> wrote:
[quote]--> Kolb-List message posted by: "Ron (at) KFHU" <captainron1(at)cox.net (captainron1(at)cox.net)>
You should not start a post with a "no", as that indicates rudeness or belligerence, if you must say no you need to enter it after you made you counter point or made your explanation.
P-Factor is short for propeller factor Dana, in other words the entire effect of the propeller from induced drag to counter torque is at play, so if you do not want to come across as an ignorant jerk trying to raise yourself to a level of expertise that you have yet to show, you need to word your answers quite differently.
Having said that now let me read the rest of your post, and see if there is anything worth considering in it.
Okay I read the rest of your message and I am not seeing where your Jerk Off "No" is coming from.
So post your explanation as to what exactly your " jerk off " no is about.
You may be one of those jack asses where being civil to you indicates a weakness, I run into people like that every so often and after I get over their * rudeness * I respond to them in the manner that they understand and deserve, so thread carefully especially if you don't know who you are talking to Dana. Trust me when I say to you that I am way better than you at flaming, so if you choose to be uncivil not only will you disturb this entire list but also come out on the short end of the stick.
Ron (at) KFHU
===
---- Dana Hague <d-m-hague(at)comcast.net (d-m-hague(at)comcast.net)> wrote:
=============
--> Kolb-List message posted by: Dana Hague <d-m-hague(at)comcast.net (d-m-hague(at)comcast.net)>
At 11:33 AM 7/15/2009, Ron (at) KFHU wrote:
>...The Kolb thrust line is pretty close to its center of mass so its
>moment arm for affecting deviation from flight path is pretty weak, as
>compared to a Cessna 150...
No, the effect of P-factor is a torque around the yaw axis, and a torque
("couple" in engineering terms) is independent of location.
However, P-factor is a factor of the relative wind, and there are two
things on a Kolb that would tend to reduce it. First, the low speed means
that the propeller induced inflow (air is "sucked" into the prop) is a
larger factor, tending to align the airflow with the thrust line before it
even gets to the prop. Second, the location of the prop behind the wing
means that it's operating in the wing induced downflow rather than the free
stream direction. This latter could cause a P-factor in either direction
depending on the thrust line and the direction of the downflow vector.
-Dana
--
New safety announcement from the Department of Homeland
Security: Securely duct tape shut any books you may own about civil
liberties or the U.S. Constitution.
--
kugelair.com
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arget="_blank">http://www.matronics.com/Navigator?Kolb-List
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le, List Admin.
="_blank">http://www.matronics.com/contribution
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John Hauck

Joined: 09 Jan 2006 Posts: 4639 Location: Titus, Alabama (hauck's holler)
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Posted: Wed Jul 15, 2009 12:31 pm Post subject: Victor 1+ Report |
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Trust me when I say to you that I am way better than you at flaming, so if
you choose to be uncivil not only will you disturb this entire list but also
come out on the short end of the stick.
Captain Ron:
Looks like your post would have been better sent back copy and not to the
Kolb List.
I can't find anything in it Kolb related.
Thanks,
john h
mkIII
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_________________ John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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lucien
Joined: 03 Jun 2007 Posts: 721 Location: santa fe, NM
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Posted: Wed Jul 15, 2009 12:57 pm Post subject: Re: Victor 1+ Report |
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Dana wrote: |
Is that the way it's supposed to be? I was under the impression that the
low boom Kolbs had the boom tube angled upwards from the pod in level
flight, so if the thrust line was parallel to the boom you'd get P-factor
in the opposite direction, i.e. a RH turning prop would then cause a right
turning tendency.
-Dana
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Well the thrust line wasn't parallel to the boom tube on mine, it was basically in line with the chord of the main wing. So in flight it all "lined up" as far as I could tell, the wing flying at some small positive AoA and maybe the prop disk canted backwards a little with respect to the relative wind. The boom tube would "ride" pointing up a bit.
So if there was any P factor at cruise it would have been trying to yaw to the left.
My plane did have trim tabs on an aileron and on the rudder but I don't remember which way they were oriented. And also, the left rudder was needed generally only on the takeoff roll. I don't remember much of anything like having to trim once it was in the air.
I don't see how it could have been anything else but the corkscrewing airflow as torque and P factor effects on the ground or at high AoA's were all acting in the opposite direction.
Could be why my titan doesn't need much rudder at t/o - it's got about 800,000 times more torque and P factor than my FSII did with the 912 100 horse and the huge honking powerfin on it. That may be enough to cancel out the corkscrewing airflow on the vertical stab?....
LS
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_________________ LS
Titan II SS |
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jbhart(at)onlyinternet.ne Guest
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Posted: Wed Jul 15, 2009 1:12 pm Post subject: Victor 1+ Report |
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At 11:23 AM 7/15/09 -0500, you wrote:
Quote: |
Relative wind has affected every aircraft I ever flew, fixed and rotary
wing. The fix was step on the ball and get it centered.
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Once again, my point is that if your plane is well trimmed out at cruise,
you will not have to step on the ball.
Quote: |
Cork screw prop wash, on my mkIII, is not theory.
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I should have said, I believe the effects are greatly over rated in
comparison to propeller torque reaction.
Quote: |
Mine keeps the ball of the slip/skid indicator centered.
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I am pleased that you do not have to step on the ball, it becomes tiresome.
Quote: |
I agree with the above, but not enough to try and correct at normal cruise.
I think my cruise speed is what the aircraft was designed for. If I slow it
down in comparison to the way you fly, everything changes, including the
prop angle of attack in relative wind.
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I have never indicated that you or anyone should slow down to FireFly cruise
speed. I have always used the words "trimmed for cruise". You have already
indicated that you kick the ball to center and then that you don't need
to.
Quote: |
Never seen or flown a Kolb aircraft that did not have more than enough prop
wash over the tail to take care of any situation. If there is not enough
prop wash over your FF's tail, it is because you have screwed it up
adjusting prop thrust lines and flying with under powered engines.
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Thank you, my underpowered FireFly can easily exceed 55 knots and I am very
pleased with the effortless way it flys.
Quote: |
There are occassions when a burst of full throttle is all that saved my mkIII from
ground looping, as experienced during my flight from Gallup, NM, to MV,
while landing at Chinle, AZ.
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John, you decided to move your landing gear foward and to run large low
pressure tires. The further the cg is behind the landing gear the pilot
must exercise greater skill to prevent ground looping.
Quote: |
I am happy with my mkIII after nearly 3,000 hours and 17 years living with
and flying it. You would not be happy with my mkIII and I would not be
happy with your FF, the way you have it set up.
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This is a little presumptous.
That is what makes the Kolb
Quote: | List what it is. If I don't happen to agree with someone, doesn't mean I
don't like them or what they are doing. Just not the way I do it.
I don't tell folks how to do it. I try to share what I do and let you all
pick and choose what they want, if anything.
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I believe this is a good philosophy.
Quote: | Getting ready to get out of here in the morning. Got a long boring 800
miles to fly in some really hot, humid, hazy weather. It gets worse as I
get further NE, closer to the larger population centers. I also have to
contend with the Washington DC restricted area. Going to make me fly
further north and west than I would normally. Thanks to the terrorists!!!
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John, have a good trip and keep the ball centered. (joke)
Jack B. Hart FF004
Winchester, IN
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russ(at)rkiphoto.com Guest
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Posted: Wed Jul 15, 2009 3:12 pm Post subject: Victor 1+ Report |
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Ron
I don't know you, but please don't re-start this business of
insulting other people on the list.
Like your saying 'ignorant jerk', 'jerk-off no', 'jackasses',
'uncivil', & even 'rudeness' and 'belligerance'
None of us need that.
It's counterproductive.
We had a lot of that some time ago, from another Kolber.
We need no more 'flaming'
Please stop.
Thanx
Russ K
On Jul 15, 2009, at 3:50 PM, Ron (at) KFHU wrote:
Quote: |
You should not start a post with a "no", as that indicates rudeness
or belligerence, if you must say no you need to enter it after you
made you counter point or made your explanation.
P-Factor is short for propeller factor Dana, in other words the
entire effect of the propeller from induced drag to counter torque
is at play, so if you do not want to come across as an ignorant
jerk trying to raise yourself to a level of expertise that you have
yet to show, you need to word your answers quite differently.
Having said that now let me read the rest of your post, and see if
there is anything worth considering in it.
Okay I read the rest of your message and I am not seeing where your
Jerk Off "No" is coming from.
So post your explanation as to what exactly your " jerk off " no is
about.
You may be one of those jack asses where being civil to you
indicates a weakness, I run into people like that every so often
and after I get over their * rudeness * I respond to them in the
manner that they understand and deserve, so thread carefully
especially if you don't know who you are talking to Dana. Trust me
when I say to you that I am way better than you at flaming, so if
you choose to be uncivil not only will you disturb this entire list
but also come out on the short end of the stick.
Ron (at) KFHU
============================
---- Dana Hague <d-m-hague(at)comcast.net> wrote:
=============
At 11:33 AM 7/15/2009, Ron (at) KFHU wrote:
> ...The Kolb thrust line is pretty close to its center of mass so its
> moment arm for affecting deviation from flight path is pretty
> weak, as
> compared to a Cessna 150...
No, the effect of P-factor is a torque around the yaw axis, and a
torque
("couple" in engineering terms) is independent of location.
However, P-factor is a factor of the relative wind, and there are two
things on a Kolb that would tend to reduce it. First, the low
speed means
that the propeller induced inflow (air is "sucked" into the prop) is a
larger factor, tending to align the airflow with the thrust line
before it
even gets to the prop. Second, the location of the prop behind the
wing
means that it's operating in the wing induced downflow rather than
the free
stream direction. This latter could cause a P-factor in either
direction
depending on the thrust line and the direction of the downflow vector.
-Dana
--
New safety announcement from the Department of Homeland
Security: Securely duct tape shut any books you may own about civil
liberties or the U.S. Constitution.
--
kugelair.com
|
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captainron1(at)cox.net Guest
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Posted: Wed Jul 15, 2009 4:11 pm Post subject: Victor 1+ Report |
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That's correct it was not meant for public consumption.
My apologies to all.
Ron
==============
---- John Hauck <jhauck(at)elmore.rr.com> wrote:
=============
Trust me when I say to you that I am way better than you at flaming, so if
you choose to be uncivil not only will you disturb this entire list but also
come out on the short end of the stick.
Captain Ron:
Looks like your post would have been better sent back copy and not to the
Kolb List.
I can't find anything in it Kolb related.
Thanks,
john h
mkIII
--
kugelair.com
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Dana

Joined: 13 Dec 2007 Posts: 1047 Location: Connecticut, USA
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Posted: Wed Jul 15, 2009 6:43 pm Post subject: Victor 1+ Report |
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At 03:50 PM 7/15/2009, Ron (at) KFHU wrote:
Quote: | You should not start a post with a "no", as that indicates rudeness or belligerence, if you must say no you need to enter it after you made you counter point or made your explanation.
P-Factor is short for propeller factor Dana, in other words the entire effect of the propeller from induced drag to counter torque is at play, so if you do not want to come across as an ignorant jerk trying to raise yourself to a level of expertise that you have yet to show, you need to word your answers quite differently.
Having said that now let me read the rest of your post, and see if there is anything worth considering in it.
Okay I read the rest of your message and I am not seeing where your Jerk Off "No" is coming from.
So post your explanation as to what exactly your " jerk off " no is about.
You may be one of those jack asses... |
What on earth is your problem? You made an incorrect statement, I said so and explained why it was incorrect. Would it have been better if I said, "Um, gee, I'm terribly sorry, but I think you may have made a teeny weeny little mistake, I think you might be mistaken..."? Your own reaction to being corrected is the way of an "ignorant jerk" (your words, not mine, I prefer to be polite). I am quite aware of what P-factor is (a more accurate term is "asymmetric blade thrust"), they kinda taught us about it when I was earning a degree in aerospace engineering 30 years ago... and they taught it in ground school when I was learning to fly around the same time.
Now, go back and read my post, where I fully explained what the "no" was about. If you want to discuss it further, ask politely, without comments about "ignorant jerks" and "jack asses".
-Dana
--
The number of elected federal officials is limited to congress, the president and the vice president. That's only 537 people. The federal bureaucracy numbers in the millions..... [quote][b]
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zeprep251(at)aol.com Guest
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Posted: Thu Jul 16, 2009 4:49 am Post subject: Victor 1+ Report |
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The best example of aircraft designed to neutralize all of those forces is ,in my opinion,the Ercoupe.The wide rudder placement,and the engine mount that looks like it's bent.But it was still fast, 100+ on 75hp.
G.Aman
--
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russ(at)rkiphoto.com Guest
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Posted: Thu Jul 16, 2009 9:43 am Post subject: Victor 1+ Report |
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Even for private consumption, that's some unnecessary harsh talk
do not archive
On Jul 15, 2009, at 8:07 PM, Ron (at) KFHU wrote:
Quote: |
That's correct it was not meant for public consumption.
My apologies to all.
Ron
==============
---- John Hauck <jhauck(at)elmore.rr.com> wrote:
=============
Trust me when I say to you that I am way better than you at
flaming, so if
you choose to be uncivil not only will you disturb this entire list
but also
come out on the short end of the stick.
> Ron (at) KFHU
Captain Ron:
Looks like your post would have been better sent back copy and not
to the
Kolb List.
I can't find anything in it Kolb related.
Thanks,
john h
mkIII
--
kugelair.com
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