KR> Thrust line

[Craig Williams]

If you go to my webpage you can see pictures of the fixture I just built for my
O-235.  They are listed under the 3/11/15 update.

Craig
http://www.kr2seafury.com/

> On September 23, 2015 at 5:58 PM Mike Arnold via KRnet  list.krnet.org>
> wrote:
> 
> 
> So, no one wants to wade in on the thrust line on the fire wall for a KR2
> huh. No Aeronautical engineers out there.
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
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> options

KR> Thrust line

[Mike Arnold]

Thanks Larry and those that responded. The  plane is already built but no
engine or mount. It was originally built with a 0-200. I am putting a VW
1835 on it. Insert sad emote here. I am going to build an adjustable jig.
You thought I was going to say "engine mount" didn't you. Ha ha ha,  . .
Hu
On Sep 23, 2015 6:29 PM, "Flesner via KRnet"  wrote:

> At 04:58 PM 9/23/2015, you wrote:
>
>> So, no one wants to wade in on the thrust line on the fire wall for a KR2
>> huh. No Aeronautical engineers out there.
>>
> ++
>
> I'm sure there are.  I'm not an engineer but my opinion is very
> affordable. The plans place the thrust line basically in line with the top
> longeron as others have stated.  Do you plan on making major changes from
> the plan or why do you ask?  Moving the thrust line considerably above or
> below that line could / will cause greater pitch changes with power changes
> when compared to a top longeron thrust line.  Few aircraft designs place
> the thrust line low because of prop ground clearance but many have a very
> high thrust line like the Kolb, challenger, and others.  These designs are
> quite flyable but the pilot must be aware and respond to major pitch
> changes with power changes.  An inch or two above or below the top longeron
> in a KR  would probably have little noticeable effect with power changes
> but, like I said, I'm not an engineer.  And like I said, my opinion is
> affordable.  It cost you nothing at all. :-)
>
> Larry Flesner
>
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
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>

KR> Thrust line

[Flesner]

At 04:58 PM 9/23/2015, you wrote:
>So, no one wants to wade in on the thrust line on the fire wall for a KR2
>huh. No Aeronautical engineers out there.
++

I'm sure there are.  I'm not an engineer but my opinion is very 
affordable. The plans place the thrust line basically in line with 
the top longeron as others have stated.  Do you plan on making major 
changes from the plan or why do you ask?  Moving the thrust line 
considerably above or below that line could / will cause greater 
pitch changes with power changes when compared to a top longeron 
thrust line.  Few aircraft designs place the thrust line low because 
of prop ground clearance but many have a very high thrust line like 
the Kolb, challenger, and others.  These designs are quite flyable 
but the pilot must be aware and respond to major pitch changes with 
power changes.  An inch or two above or below the top longeron in a 
KR  would probably have little noticeable effect with power changes 
but, like I said, I'm not an engineer.  And like I said, my opinion 
is affordable.  It cost you nothing at all. :-)

Larry Flesner 

KR> Thrust line

[James Babcock]

If I recall correctly (from about 1989) I tried to get the engine thrust line 
at center of crankshaft to line up with the top longeron. I did not offset the 
engine laterally to compensate for p factor like I have read that some planes 
do. Too much math for me. 
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> On Sep 23, 2015, at 4:59 PM, Mike Arnold via KRnet  
> wrote:
> 
> So, no one wants to wade in on the thrust line on the fire wall for a KR2
> huh. No Aeronautical engineers out there.
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change 
> options

KR> Thrust line

[Mike Arnold]

So, no one wants to wade in on the thrust line on the fire wall for a KR2
huh. No Aeronautical engineers out there.

KR> Thrust line

[Dan Prichard]

I'm not an engineer but I've been in the presence of a few. I was told the 
thrust line is typically in plane with the top longeron.  I set mine at 2.5"s 
below to accommodate the Corvair and the starter. Check out the KRnet Archives. 
Type "thrust line " in the email body section and watch the well of knowledge 
spring out. 

Dan Prichard
Portland Oregon 

Sent from my iPhone

> On Sep 23, 2015, at 2:58 PM, Mike Arnold via KRnet  
> wrote:
> 
> So, no one wants to wade in on the thrust line on the fire wall for a KR2
> huh. No Aeronautical engineers out there.
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change 
> options

KR> Thrust line

[Mike Arnold]

How do you locate the thrust line on the fire wall. Makeing my own motor
mount.

KR> Thrust line offsets ....

[Martin Pearce]

Hi Barry
I guess that is what I was seeing too . I instruct a bit in the
Jab160/170 and whilst there are yaw changes with throttle, they are quite
subtle, although the pitch change, tho gentle, is quite noticeable. On the
KR2 I don't (didn't) see much pitch change with throttle, and I suspect the
pitch change differences are associated with high / low wing and the thrust
/ drag line differences.

Have you thought about changing your thrust line offset at all, Barry? I
think the prop swings clockwise from the viewpoint of the cockpit? Do you
find you need increasing right rudder as the power increases? 

Cheers
Martin
Martin Pearce
KR2  19 - 7814
rocketdri...@optusnet.com.au






-Original Message-
From: Barry Kruyssen [mailto:k...@bigpond.com] 
Sent: Tuesday, 10 April 2012 10:49 AM
To: 'KRnet'
Subject: RE: KR> Thrust line offsets  

Hi Martin

I get enormous yaw variations with different throttle settings with a Jabiru
2200 engine in an otherwise stock KR2.

Regards
Barry Kruyssen
http://www.athertonairport.com.au/kr2/index.html
19-3873




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info at http://www.krnet.org/info.html

KR> Thrust line offsets ....

[Virgil N. Salisbury]

Put washers on one side of the mount until satisfied with the results,
Virg

On 4/10/2012 6:27 AM, Mark Langford wrote:
> I guess I scanned Martin's email too quickly before, and missed that he was
> talking about the horizontal plane, rather than the vertical.  I built my
> rudder with no offset because I wasn't positive that I was going to use a VW
> or Corvair.  But the cure for that big Corvair engine was as simple as a 1"
> x 4" aluminum tab on the rudder with about a 25 degree bend on it.  I'd
> guess that a 2-3 degree offset would be plenty to correct for it.  As for
> yaw variations are various throttle settings, I never notice mine except at
> wide open on takeoff.  The rest of the time I don't mess around with the
> rudder pedals unless on takeoff or landing, unless I do it subconsciously
> and don't notice, which is possible...
>
>
> Mark Langford
> m...@n56ml.com
> see experimental N56ML at www.N56ML.com
>

KR> Thrust line offsets ....

[Mark Langford]

I guess I scanned Martin's email too quickly before, and missed that he was
talking about the horizontal plane, rather than the vertical.  I built my
rudder with no offset because I wasn't positive that I was going to use a VW
or Corvair.  But the cure for that big Corvair engine was as simple as a 1"
x 4" aluminum tab on the rudder with about a 25 degree bend on it.  I'd
guess that a 2-3 degree offset would be plenty to correct for it.  As for
yaw variations are various throttle settings, I never notice mine except at
wide open on takeoff.  The rest of the time I don't mess around with the
rudder pedals unless on takeoff or landing, unless I do it subconsciously
and don't notice, which is possible...


Mark Langford
m...@n56ml.com 
see experimental N56ML at www.N56ML.com  


-Original Message-
From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf
Of Martin Pearce
Sent: Monday, April 09, 2012 4:59 PM
To: kr...@mylist.net
Subject: KR> Thrust line offsets  

Does anyone have thoughts / experience with the best thrust line offset to
use for the KR2?

I have a suby motor with Redrive so the prop turns clockwise viewed from the
cockpit. My engine mount appears to have close to 1 deg offset to the right
built into it, but I have heard that 3 deg is likely to be closer to what is
best. The a'c has a fixed rudder trim tab with quite a lot of right rudder
bias (tab bent to the left) and, as I recall, there was a fair bit of yaw
variation with throttle. Pitch changes with throttle seemed to be fairly
minimal  

Would appreciate some guidance as I will soon be remounting the engine to
the airframe 

Cheers

Martin Pearce

KR2  19 - 7814

rocketdri...@optusnet.com.au

KR> Thrust line offsets ....

[Barry Kruyssen]

Hi Martin

I get enormous yaw variations with different throttle settings with a Jabiru
2200 engine in an otherwise stock KR2.

Regards
Barry Kruyssen
http://www.athertonairport.com.au/kr2/index.html 
19-3873

-Original Message-
From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf
Of Martin Pearce
Sent: Tuesday, 10 April 2012 7:59 AM
To: kr...@mylist.net
Subject: KR> Thrust line offsets  

Does anyone have thoughts / experience with the best thrust line offset to
use for the KR2?



I have a suby motor with Redrive so the prop turns clockwise viewed from the
cockpit. My engine mount appears to have close to 1 deg offset to the right
built into it, but I have heard that 3 deg is likely to be closer to what is
best. The a'c has a fixed rudder trim tab with quite a lot of right rudder
bias (tab bent to the left) and, as I recall, there was a fair bit of yaw
variation with throttle. Pitch changes with throttle seemed to be fairly
minimal  



Would appreciate some guidance as I will soon be remounting the engine to
the airframe 



Cheers





Martin Pearce

KR2  19 - 7814

rocketdri...@optusnet.com.au







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KR> Thrust line offsets ....

[Tony King]

Good to know the aircraft works fine with the crank centreline on a
plane parallel with the top longerons, but I think Martin's question
was about the alignment of the engine in relation to the vertical
plane along the aircraft's centreline.  In other words, is the mount
configured so as to position the thrust line at an angle to the
aircraft's centreline (to counteract torque effects and thus reduce
the amount of rudder trim required) and if so by how much?

I can see a big dependency here on the amount of torque the engine is
producing, so I doubt there is a single number for all cases.  And as
Mark has suggested it'd be a lot of work to try different settings to
get to the ideal number for a given combination.  Nevertheless it'd
certainly be interesting to learn what different people have done.

On another note, I flipped my 'boat' right way up on the bench for the
first time a few days ago.  Starting to feel like I really will turn
this pile of sticks into an aircraft :-)

Cheers,

Tony King
Queensland Australia

On 10 April 2012 09:41, Mark Langford  wrote:
> Martin Pearce wrote:
>
>>Does anyone have thoughts / experience with the best thrust line offset to
>>use for the KR2?
>
> I doubt anybody's done testing with various thrust lines to know what
> works
> best, and they are essentially all different anyway, but apparently the
> plans work fine (crank centerline along the plane of the top of the
> longeron) and what I used works (dropped ~2.625" below the top of the
> longeron).  Anywhere in there should work, and I'm guessing the range is
> larger.  I dropped mine to get the engine lower for better visibility over
> the cowling.
>
> Mark Langford
> ML at N56ML.com
> website at http://www.N56ML.com
> 
>
>
> ___
> Search the KRnet Archives at http://mylist.net/private/krnet/
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html

KR> Thrust line offsets ....

[Mark Langford]

Martin Pearce wrote:

>Does anyone have thoughts / experience with the best thrust line offset to 
>use for the KR2?

I doubt anybody's done testing with various thrust lines to know what works 
best, and they are essentially all different anyway, but apparently the 
plans work fine (crank centerline along the plane of the top of the 
longeron) and what I used works (dropped ~2.625" below the top of the 
longeron).  Anywhere in there should work, and I'm guessing the range is 
larger.  I dropped mine to get the engine lower for better visibility over 
the cowling.

Mark Langford
ML at N56ML.com
website at http://www.N56ML.com

KR> Thrust line offsets ....

[Dan Heath]

This has been discussed in the past and I know of no offset being
recommended.  I have a 100HP Corvair on mine and unless WW built in an
offset, which I am sure he did not, there is no offset for that awesome
power.

See N64KR at http://KRBuilder.org - Then click on the pics 
See you at the 2012 - KR Gathering in Mt. Vernon, Il – MVN – 40th
Anniversary
There is a time for building and it is over.
Daniel R. Heath - Lexington, SC
http://www.krbuilder.org/MyUSA/



-Original Message-
Does anyone have thoughts / experience with the best thrust line offset to
use for the KR2?

KR> Thrust line offsets ....

[Martin Pearce]

Does anyone have thoughts / experience with the best thrust line offset to
use for the KR2?



I have a suby motor with Redrive so the prop turns clockwise viewed from the
cockpit. My engine mount appears to have close to 1 deg offset to the right
built into it, but I have heard that 3 deg is likely to be closer to what is
best. The a'c has a fixed rudder trim tab with quite a lot of right rudder
bias (tab bent to the left) and, as I recall, there was a fair bit of yaw
variation with throttle. Pitch changes with throttle seemed to be fairly
minimal  



Would appreciate some guidance as I will soon be remounting the engine to
the airframe 



Cheers





Martin Pearce

KR2  19 - 7814

rocketdri...@optusnet.com.au

KR> thrust line

[phil brookman]

can anyone informed tell me what the thrust line is supposed to be on a 
standard kr 2 
where is it measured from 
tia

phill

KR> thrust line

[Larry&Sallie Flesner]

At 05:21 PM 5/22/2007, you wrote:
>can anyone informed tell me what the thrust line is supposed to be 
>on a standard kr 2
>where is it measured from
>tia
>
>phill
+

Without looking back at the plans I believe it should fall in the area of the
top longeron, give or take an inch or two.  It depends to some extent on
the engine installation and clearances needed.  I don't think this falls
in to the area of rocket science and close should work.

Larry Flesner

KR> thrust line

[Phil Matheson]

Phil.
The Top of the longerons ???is the normal thrust line. I do remember a 
number of builder changing , including me. I lowering my thrust line about 1 
1/2 inches below the longerons to allow the twin top mounted carbs to fit 
under the cowl line.

But One of the Famous Mark's Brothers, sorry (Mark L and Mark J ) would be a 
much better adviser than I.


Phil Matheson
SAAA Ch. 20
VH-PKR
Australia

EMAIL:   phillipmathe...@bigpond.com
KR Web Page: www.philskr2.50megs.com
http://www.vw-engines.com/ 

KR> thrust line

[Mark Langford]

phil brookman wrote:

> can anyone informed tell me what the thrust line is supposed to be on a
standard kr 2
> where is it measured from

Below is a post from 2005 that I found in the archives
(http://www.maddyhome.com/krsrch/index.jsp) that pretty much sums it up.  I
had always thought it was in line with the top of the top longeron, but I
had to install my Corvair 2.375" below that if I wanted the fuel pump and
intake manifolds to not protrude through the top of my cowling.  Below is
Jeff Scott's comment:

>>The drawing I have from RR for their O-200 engine mount clearly states
that the engine CL is 1 1/2" below the top longeron.  In this case CL is
drawn as the thrust line and references the top of the upper longeron in
the drawing.  Of course you'll probably see it clearly stated as
something different on other drawings.  From previous discussions that
should be in the archives, you'll find that people have it all over the
place, but nobody seems to notice any ill effects from it not being
exactly according to any of the specs.<<

Mark Langford, Huntsville, Alabama
see KR2S project N56ML at http://home.hiwaay.net/~langford
email to N56ML "at" hiwaay.net
--

KR> thrust line

[Mark Jones]

 Phil.
> The Top of the longerons ???is the normal thrust line.
>
> But One of the Famous Mark's Brothers, sorry (Mark L and Mark J ) would be 
> a
> much better adviser than I.
>

Famous, ha...maybe crazy..mine is set 1 1/2 inches below the longeron.

Mark Jones (N886MJ)
Wales, WI
Visit my web site: www.flykr2s.com
E-mail: flyk...@wi.rr.com 

KR> Thrust Line issues

[Colin Rainey]

Don and netters
Something else came to mind the other day when considering the effects of
raised or lowered thrust line. During flight training to become CFI's we
were always told that the reason the Piper Seminole was made with a high "T"
tail as compared to its sister plane the Piper Seneca which had a
traditional tail (and 2 more seats, but that is another story) is because
the Seminole was really ear marked for the training market, and so Piper
wanted the tail in "clean air". This was supposed to make it safer to flight
train in. I am told that the same designer, later worked for Beech and
designed the Duchess, which is why so much of the configuration resembles
the Seminole.

My point for this post is this: while in most cases planes are designed with
the empennage "in the prop wash", some very successful designs are not.
These planes seem to experience less pitch change due to the change in the
amount of prop thrust over the elevator/stabilator, and the change is more a
function of airspeed/airflow. If by raising the thrust line, one lessens the
amount of prop wash over the elevator of a particular KR2 or S, that builder
may find a nice softening of the effectiveness, without becoming dangerous.
Then again it may favor one side only, causing good nose up authority, but
lose some nose down authority.

I would also think that if the builder then used a longer prop taking
advantage of the greater ground clearance, he might not have any change in
the behavior of the plane to speak of at all.

Just some ideas for thought. I was once considering a PSRU or re-drive as
some call them, for my 1915 cc VW original engine. Had I installed that, I
would have been 4 to 5 inches higher. This may be an issue many builders
have contemplated or evaluated.

Colin Rainey
brokerpi...@bellsouth.net

KR> Thrust Line issues

[D Lively]

Colin:

I spoke with Steve at GPAS and his comment was that the lowest rpm rduction of 
their PSRU would likely require to long of a prop to work with a KR2 for ground 
clearance reasons but my desire was to stick with the 3400 rpm max and not push 
the rpm up to 4400 rpm max.  I do intend water cooled heads principly for a 
"Cabin Heat" source to get away from the time honored exhaust heat muff so as 
to reduce the opportunity for CO intrusion.

I still have no clean answer on the effects of the Thrust CL change but it is 
but 5 inches which still would leave the stabilizer in the prop wash.

I learned long ago that the dumbest questions are the ones not ask!

Don



- Original Message - 
From: "Colin Rainey" 
To: "KRnet" 
Sent: Tuesday, February 20, 2007 12:07 AM
Subject: KR> Thrust Line issues


> Don and netters
> Something else came to mind the other day when considering the effects of
> raised or lowered thrust line. During flight training to become CFI's we
> were always told that the reason the Piper Seminole was made with a high "T"
> tail as compared to its sister plane the Piper Seneca which had a
> traditional tail (and 2 more seats, but that is another story) is because
> the Seminole was really ear marked for the training market, and so Piper
> wanted the tail in "clean air". This was supposed to make it safer to flight
> train in. I am told that the same designer, later worked for Beech and
> designed the Duchess, which is why so much of the configuration resembles
> the Seminole.
> 
> My point for this post is this: while in most cases planes are designed with
> the empennage "in the prop wash", some very successful designs are not.
> These planes seem to experience less pitch change due to the change in the
> amount of prop thrust over the elevator/stabilator, and the change is more a
> function of airspeed/airflow. If by raising the thrust line, one lessens the
> amount of prop wash over the elevator of a particular KR2 or S, that builder
> may find a nice softening of the effectiveness, without becoming dangerous.
> Then again it may favor one side only, causing good nose up authority, but
> lose some nose down authority.
> 
> I would also think that if the builder then used a longer prop taking
> advantage of the greater ground clearance, he might not have any change in
> the behavior of the plane to speak of at all.
> 
> Just some ideas for thought. I was once considering a PSRU or re-drive as
> some call them, for my 1915 cc VW original engine. Had I installed that, I
> would have been 4 to 5 inches higher. This may be an issue many builders
> have contemplated or evaluated.
> 
> Colin Rainey
> brokerpi...@bellsouth.net
> 
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> Post photos, introductions, and For Sale items to <A 
> HREF=http://www.kr2forum.com/phpBB2/index.php
> please see other KRnet info at http://www.krnet.org/info.html
>

KR> Thrust Line issues

[Dave Arbogast, CISSP]

Funny, my instructor called them the "Trauma - hawk" because of the T 
tail being less responsive to prop wash when you need it the most - 
stall recovery.

Raising the trust-line I would think increases the loads on the upper 
half of the firewall. Maybe not enough to worry about, but I sure like 
the idea of more ground clearance for the prop.

-dave

Colin Rainey wrote:

>Don and netters
>Something else came to mind the other day when considering the effects of
>raised or lowered thrust line. During flight training to become CFI's we
>were always told that the reason the Piper Seminole was made with a high "T"
>tail as compared to its sister plane the Piper Seneca which had a
>traditional tail (and 2 more seats, but that is another story) is because
>the Seminole was really ear marked for the training market, and so Piper
>wanted the tail in "clean air". This was supposed to make it safer to flight
>train in. I am told that the same designer, later worked for Beech and
>designed the Duchess, which is why so much of the configuration resembles
>the Seminole.
>
>My point for this post is this: while in most cases planes are designed with
>the empennage "in the prop wash", some very successful designs are not.
>These planes seem to experience less pitch change due to the change in the
>amount of prop thrust over the elevator/stabilator, and the change is more a
>function of airspeed/airflow. If by raising the thrust line, one lessens the
>amount of prop wash over the elevator of a particular KR2 or S, that builder
>may find a nice softening of the effectiveness, without becoming dangerous.
>Then again it may favor one side only, causing good nose up authority, but
>lose some nose down authority.
>
>I would also think that if the builder then used a longer prop taking
>advantage of the greater ground clearance, he might not have any change in
>the behavior of the plane to speak of at all.
>
>Just some ideas for thought. I was once considering a PSRU or re-drive as
>some call them, for my 1915 cc VW original engine. Had I installed that, I
>would have been 4 to 5 inches higher. This may be an issue many builders
>have contemplated or evaluated.
>
>Colin Rainey
>brokerpi...@bellsouth.net
>
>___
>Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
>to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
>Post photos, introductions, and For Sale items to HREF=http://www.kr2forum.com/phpBB2/index.php
>please see other KRnet info at http://www.krnet.org/info.html
>  
>

KR> Thrust Line issues

[D Lively]

Dave:

I am not at all sure what the impact of the change on the loading of the engine 
mount "Force Couple" to the firewall migkt be but I have the "GPAS" 5-pt mount 
and the "Thrust Line"  would certainly move up to or above the Pt. of 
attachment line of  the (3) upper motor-mount attatch points. 

The biggest issue to Steve @ GPAS seemed to be that of prop clearance.  That 
may well have been because I wished to hold the rpm to 3400 max and the 
resulting prop rpm would need to be sufficiently longer to get the job done 
that ground clearance would be an issue.  This was not clearly spoken but it is 
my inferance to what he said. 

Don
Burlington IA 52601


- Original Message - 
From: "Dave Arbogast, CISSP" 
To: "KRnet" 
Sent: Tuesday, February 20, 2007 11:46 AM
Subject: Re: KR> Thrust Line issues


> Funny, my instructor called them the "Trauma - hawk" because of the T 
> tail being less responsive to prop wash when you need it the most - 
> stall recovery.
> 
> Raising the trust-line I would think increases the loads on the upper 
> half of the firewall. Maybe not enough to worry about, but I sure like 
> the idea of more ground clearance for the prop.
> 
> -dave
> 
> Colin Rainey wrote:
> 
>>Don and netters
>>Something else came to mind the other day when considering the effects of
>>raised or lowered thrust line. During flight training to become CFI's we
>>were always told that the reason the Piper Seminole was made with a high "T"
>>tail as compared to its sister plane the Piper Seneca which had a
>>traditional tail (and 2 more seats, but that is another story) is because
>>the Seminole was really ear marked for the training market, and so Piper
>>wanted the tail in "clean air". This was supposed to make it safer to flight
>>train in. I am told that the same designer, later worked for Beech and
>>designed the Duchess, which is why so much of the configuration resembles
>>the Seminole.
>>
>>My point for this post is this: while in most cases planes are designed with
>>the empennage "in the prop wash", some very successful designs are not.
>>These planes seem to experience less pitch change due to the change in the
>>amount of prop thrust over the elevator/stabilator, and the change is more a
>>function of airspeed/airflow. If by raising the thrust line, one lessens the
>>amount of prop wash over the elevator of a particular KR2 or S, that builder
>>may find a nice softening of the effectiveness, without becoming dangerous.
>>Then again it may favor one side only, causing good nose up authority, but
>>lose some nose down authority.
>>
>>I would also think that if the builder then used a longer prop taking
>>advantage of the greater ground clearance, he might not have any change in
>>the behavior of the plane to speak of at all.
>>
>>Just some ideas for thought. I was once considering a PSRU or re-drive as
>>some call them, for my 1915 cc VW original engine. Had I installed that, I
>>would have been 4 to 5 inches higher. This may be an issue many builders
>>have contemplated or evaluated.
>>
>>Colin Rainey
>>brokerpi...@bellsouth.net
>>
>>___
>>Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
>>to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
>>Post photos, introductions, and For Sale items to <A 
>>HREF=http://www.kr2forum.com/phpBB2/index.php
>>please see other KRnet info at http://www.krnet.org/info.html
>>  
>>
> 
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> Post photos, introductions, and For Sale items to <A 
> HREF=http://www.kr2forum.com/phpBB2/index.php
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>

KR> Thrust Line issues

[Pete Klapp]

I learned to fly in a Tomahawk. Didn't realize landings were easy till I 
began flying a 172 !!!

Pete Klapp, KR-2S, Canton, OH


From: "Dave Arbogast, CISSP" 
Reply-To: KRnet 
To: KRnet 
Subject: Re: KR> Thrust Line issues
List-Post: krnet@list.krnet.org
Date: Tue, 20 Feb 2007 12:46:02 -0500

Funny, my instructor called them the "Trauma - hawk" because of the T
tail being less responsive to prop wash when you need it the most -
stall recovery.


 >
 >___
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HREF=http://www.kr2forum.com/phpBB2/index.php
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 >
 >

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KR> Thrust Line issues

[Dave Arbogast, CISSP]

You make me feel better !!  Kansas spam cans are what most of my time is 
in, 172 being the most. The Champ is as close to a KR2 as I have flown. 
The heel brakes took some getting used to on grass. The one Arrow I 
would not count since it is much larger.

-dave

Pete Klapp wrote:

>I learned to fly in a Tomahawk. Didn't realize landings were easy till I 
>began flying a 172 !!!
>
>Pete Klapp, KR-2S, Canton, OH
>
>
>From: "Dave Arbogast, CISSP" 
>Reply-To: KRnet 
>To: KRnet 
>Subject: Re: KR> Thrust Line issues
>Date: Tue, 20 Feb 2007 12:46:02 -0500
>
>Funny, my instructor called them the "Trauma - hawk" because of the T
>tail being less responsive to prop wash when you need it the most -
>stall recovery.
>
>
> >
> >___
> >Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> >to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> >Post photos, introductions, and For Sale items to <A 
>HREF=http://www.kr2forum.com/phpBB2/index.php
> >please see other KRnet info at http://www.krnet.org/info.html
> >
> >
>
>___
>Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
>to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
>Post photos, introductions, and For Sale items to <A 
>HREF=http://www.kr2forum.com/phpBB2/index.php
>please see other KRnet info at http://www.krnet.org/info.html
>
>_
>Want a degree but can't afford to quit? Top school degrees online - in as 
>fast as 1 year 
>http://forms.nextag.com/goto.jsp?url=/serv/main/buyer/education.jsp?doSearch=n&tm=y&search=education_text_links_88_h288c&s=4079&p=5116
>
>
>___
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>  
>

KR> Thrust Line issues

[Mark Wegmet]

Rumor has it that it was called a "Trauma-hawk" because it was "spin
friendly". :-)


-Original Message-
From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf
Of Dave Arbogast, CISSP
Sent: Tuesday, February 20, 2007 11:46 AM
To: KRnet
Subject: Re: KR> Thrust Line issues

Funny, my instructor called them the "Trauma - hawk" because of the T 
tail being less responsive to prop wash when you need it the most - 
stall recovery.

Raising the trust-line I would think increases the loads on the upper 
half of the firewall. Maybe not enough to worry about, but I sure like 
the idea of more ground clearance for the prop.

-dave

Colin Rainey wrote:

>Don and netters
>Something else came to mind the other day when considering the effects of
>raised or lowered thrust line. During flight training to become CFI's we
>were always told that the reason the Piper Seminole was made with a high
"T"
>tail as compared to its sister plane the Piper Seneca which had a
>traditional tail (and 2 more seats, but that is another story) is because
>the Seminole was really ear marked for the training market, and so Piper
>wanted the tail in "clean air". This was supposed to make it safer to
flight
>train in. I am told that the same designer, later worked for Beech and
>designed the Duchess, which is why so much of the configuration resembles
>the Seminole.
>
>My point for this post is this: while in most cases planes are designed
with
>the empennage "in the prop wash", some very successful designs are not.
>These planes seem to experience less pitch change due to the change in the
>amount of prop thrust over the elevator/stabilator, and the change is more
a
>function of airspeed/airflow. If by raising the thrust line, one lessens
the
>amount of prop wash over the elevator of a particular KR2 or S, that
builder
>may find a nice softening of the effectiveness, without becoming dangerous.
>Then again it may favor one side only, causing good nose up authority, but
>lose some nose down authority.
>
>I would also think that if the builder then used a longer prop taking
>advantage of the greater ground clearance, he might not have any change in
>the behavior of the plane to speak of at all.
>
>Just some ideas for thought. I was once considering a PSRU or re-drive as
>some call them, for my 1915 cc VW original engine. Had I installed that, I
>would have been 4 to 5 inches higher. This may be an issue many builders
>have contemplated or evaluated.
>
>Colin Rainey
>brokerpi...@bellsouth.net
>
>___
>Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
>to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
>Post photos, introductions, and For Sale items to <A
HREF=http://www.kr2forum.com/phpBB2/index.php
>please see other KRnet info at http://www.krnet.org/info.html
>  
>

___
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Post photos, introductions, and For Sale items to <A
HREF=http://www.kr2forum.com/phpBB2/index.php
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5:01 PM

KR> Thrust Line

[Phil Matheson]

I have been looking for info on the correct thrust line, Others have talked
about the
T/L being equal to the top longerons, If I fit my engines cowls and sort out
he centre of the prop outlet, the T/L seems to be approx 1 - 3/4 inches
below the T/L.
Can anyone add to this.

Phil Matheson
mathe...@dodo.com.au
VH-PKR  ( Phil's KR)
61 3 58833588
Australia.( Down Under)
See My KR2 Building Web Page at:
http://mywebpage.netscape.com/flyingkrphil/VHPKR.html

See our VW Engines and Home built web page at
http://www.vw-engines.com/
www.homebuilt-aviation.com/

KR> Thrust Line

[Mark Langford]

Phil Matheson wrote:

> I have been looking for info on the correct thrust line, Others have
talked
> about the
> T/L being equal to the top longerons, If I fit my engines cowls and sort
out
> he centre of the prop outlet, the T/L seems to be approx 1 - 3/4 inches
> below the T/L.
> Can anyone add to this.

The Corvair folks (including three that are flying now, Makish, Lester, and
Clapp) are using an engine mount that puts the thrust line 2.375" below the
longeron, and it seems to work fine.  I think I've seen something very close
to that in an old Newsletter, but most references point to the longeron line
as the thrust line.  Apparently either one works fine, so you're in the
ballpark.

The DAR comes today (he's up here signing off an RV and a Baby Lakes
anyway), but after a frenzied attempt to get ready, there's no way in the
world he's going to sign me off today.  There are way too many things to do
before it's airworthy (which is not news to me, but I needed a reality check
to make me realize it's not going to happen today)...

Mark Langford, Huntsville, AL
N56ML at hiwaay.net
see KR2S project N56ML at http://home.hiwaay.net/~langford

KR> Thrust Line

[Mark Jones]

Mark,
Good luck with your DAR. You never knowgive him a few Amberbocks and he
may just let you have it. Literally Please give us a report later as to
how it goes.

Mark Jones (N886MJ)
Wales, WI 


-Original Message-
From: Mark Langford [mailto:n5...@hiwaay.net] 
Sent: Wednesday, September 01, 2004 6:57 AM
To: KRnet
Subject: Re: KR> Thrust Line

Phil Matheson wrote:

> I have been looking for info on the correct thrust line, Others have
talked
> about the
> T/L being equal to the top longerons, If I fit my engines cowls and sort
out
> he centre of the prop outlet, the T/L seems to be approx 1 - 3/4 inches
> below the T/L.
> Can anyone add to this.

The Corvair folks (including three that are flying now, Makish, Lester, and
Clapp) are using an engine mount that puts the thrust line 2.375" below the
longeron, and it seems to work fine.  I think I've seen something very close
to that in an old Newsletter, but most references point to the longeron line
as the thrust line.  Apparently either one works fine, so you're in the
ballpark.

The DAR comes today (he's up here signing off an RV and a Baby Lakes
anyway), but after a frenzied attempt to get ready, there's no way in the
world he's going to sign me off today.  There are way too many things to do
before it's airworthy (which is not news to me, but I needed a reality check
to make me realize it's not going to happen today)...

Mark Langford, Huntsville, AL
N56ML at hiwaay.net
see KR2S project N56ML at http://home.hiwaay.net/~langford


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KR> Thrust line data

[Bob]

Mark..sent the headsets Monday..They were 45 each..the venturi were 25
each..bob
Mark Langford wrote:
> 
> Steve McGee wrote:
> 
> >> I know I have seen this mentioned before both here and noticed it in 
> >> web
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html

KR> Thrust line data

[Steve and Lori McGee]

I know I have seen this mentioned before both here and noticed it in web sites, 
but have not noticed it in the manual or on the drawings.   I take it I am 
missing something here as everyone that has built their plane had to figure 
this out. Langford mentions being high or low from the main longerons (I 
forget and don't want to look again) but should be ok because of blah blah...   
Where is this data and how is it measured?  What are typical tolerances for the 
KR2S.


Steve McGee
Endeavor Wi. USA
Building a KR2S widened.
lmc...@maqs.net 

KR> Thrust line data

[Mark Langford]

Steve McGee wrote:

>> I know I have seen this mentioned before both here and noticed it in web
sites, but have not noticed it in the manual or on the drawings.   I take it
I am missing something here as everyone that has built their plane had to
figure this out. Langford mentions being high or low from the main
longerons (I forget and don't want to look again) but should be ok because
of blah blah...   Where is this data and how is it measured?  <<

A quick trip to the KRnet archives at
http://www.maddyhome.com/krsrch/index.jsp using the subject of "thrust" will
get you 47 hits on the subject.The reason there are so many hits is
because there's no mention of it in the plans, and most people have had to
just figure out the blah, blah  part.  One of the many reasons there's a
KRnet, and a KRnet archive...

Mark Langford, Huntsville, Alabama
N56ML "at" hiwaay.net
see KR2S project at http://home.hiwaay.net/~langford

KR> Thrust line data

[Mark Langford]

I guess I should have answered your question, which is that it's generally
considered to be in the same plane as the top of the top longeron.  That's
been arrived at by the fact that if you buy an RR or Revmaster cowling,
that's where the center of the prop hole ends up, blah, blah, blah...

Mark Langford, Huntsville, Alabama
N56ML "at" hiwaay.net
see KR2S project at http://home.hiwaay.net/~langford