Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

'Vertical' CG

Matronics Email Lists Forum Index -> Kolb-List

View previous topic :: View next topic

Author Message

Ed in JXN

Joined: 24 Mar 2006
Posts: 122

Posted: Wed Mar 11, 2009 12:04 pm Post subject: 'Vertical' CG

Hi Rick,

  

         I've  neither heard of 'vertical' CG, nor found anything in any manuals.  How  would one calculate it, and where does this term come from?  CG is just  that, a point around which the aircraft rotates in any axis. Some aircraft are  more prone to being displaced during low-speed taxi, but the most  susceptible would have to be light weight coupled with lots of exposed  surface area, which means a Kolb or other ultralight. Control displacement  during taxi in a wind is the same for high- or low-wing aircraft, but varies if  nosedragger or conventional gear.

  

 Ed in JXN

 MkII/503

 [quote]   ---

aslsa.rng(at)gmail.com
Guest

Posted: Wed Mar 11, 2009 1:56 pm Post subject: 'Vertical' CG

Since the effect of having 300lb of fuel weight 7' above the roll center of the aircraft (while on the ground the roll center is between the tires and at the surface) was mentioned repeatedly to me by my instructor, and on my check ride by the DPE, it seems I was meant to know about it and take heed.

 No, you won't find it in flight manuals, those decisions were made for you by the designers and engineers and you can't change them like you can fore and aft weight changes in relation to the aerodynamic center. 

 By experience I can tell you that on the ground a "K" model 172 with long range tanks handles differently in a crosswind than a "P" model with standard tanks (20 gallons and 120 lb. difference). The extra weight and the difference in landing gear track makes the "K" model more sensitive to gusts while taxiing, even though there are no other differences between the aircraft. Yes, the extra mass has more inertia, but given that both aircraft have the same size ailerons and the pilot has to have more force to stop the movement of the greater mass once it's started, the only way to get it is more aileron deflection.

 By analogy consider the roll characteristics of an Alfa Romeo Spider and a GMC Yukon. What happens to either vehicle when they are hit by a 40 mph side wind as when driving out of the wind shadow of a hedge row along side the highway? Which has the more severe response?

 Every object in an aircraft has a center of mass and a moment arm from the roll, pitch and yaw axis. How those masses are arranged will effect the handling of the aircraft whether on the ground or in the air. Whether it is critical to the aircraft depends on the aircraft's mission. 

 For instance, how many competetive aerobatic aircraft have you seen lately that are not a shoulder wing design? If you want fast roll response you put the center of mass of the wings on the roll axis of the aircraft.

 Now, the question is, does moving the fuel tank upward have an effect on the aircraft's ground handling? 

Yes, you've changed the moment arm through which a mass acts.

Will you notice it?

 I don't know.

Will it be critical?

I don't know.

I do know that to say categorically it has no effect is ridiculous on its face.

Rick



 On Wed, Mar 11, 2009 at 2:56 PM, Ed Chmielewski <edchmiel(at)mindspring.com (edchmiel(at)mindspring.com)> wrote:

[quote]        Hi Rick,

  

         I've  neither heard of 'vertical' CG, nor found anything in any manuals.  How  would one calculate it, and where does this term come from?  CG is just  that, a point around which the aircraft rotates in any axis. Some aircraft are  more prone to being displaced during low-speed taxi, but the most  susceptible would have to be light weight coupled with lots of exposed  surface area, which means a Kolb or other ultralight. Control displacement  during taxi in a wind is the same for high- or low-wing aircraft, but varies if  nosedragger or conventional gear.

  

 Ed in JXN

 MkII/503

 [quote]   ---

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Mar 11, 2009 2:19 pm Post subject: 'Vertical' CG

At 05:55 PM 3/11/2009, Richard Girard wrote:

 	  Quote: 	
		  By experience I can tell you that on the ground a "K" model 172 with long 

range tanks handles differently in a crosswind than a "P" model with 

standard tanks (20 gallons and 120 lb. difference). The extra weight and 

the difference in landing gear track makes the "K" model more sensitive to 

gusts while taxiing, even though there are no other differences between 

the aircraft. Yes, the extra mass has more inertia, but given that both 

aircraft have the same size ailerons and the pilot has to have more force 

to stop the movement of the greater mass once it's started, the only way 

to get it is more aileron deflection.


	


I don't know what the landing gear differences are, but what you're talking 

about is more a function of roll moment of inertia (presumably because the 

tanks extend farther outboard?) then vertical CG location.



If a wind gust lifts a wing, the aircraft with more roll inertia won't roll 

as far, so it takes the same amount of aileron to return it to neutral, if 

the pilot reacts in the same amount of time.



If, however, the pilot reacts not after the same amount of time, but after 

the bank angle reaches a certain point, then it WILL take more aileron 

deflection (or more time) to return to neutral.



 	  Quote: 	
		  By analogy consider the roll characteristics of an Alfa Romeo Spider and a 

GMC Yukon. What happens to either vehicle when they are hit by a 40 mph 

side wind as when driving out of the wind shadow of a hedge row along side 

the highway? Which has the more severe response?


	


The SUV, but because it has more side area, not because it's heavier.



 	  Quote: 	
		  Now, the question is, does moving the fuel tank upward have an effect on 

the aircraft's ground handling?

Yes, you've changed the moment arm through which a mass acts.


	


Yes, if you make a sharp turn when turning fast... same as the difference 

between the sports car and the SUV in a sharp turn (that IS due to the 

higher CG; a separate issue from wind effects).  It doesn't effect how you 

use your controls for crosswind taxiing; if anything it _reduces_ or slows 

the immediate felt effect of a gust (but may require more correction if you 

let it go farther).



-Dana

--

  A seminar on Time Travel will be held two weeks ago.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Mar 11, 2009 2:30 pm Post subject: 'Vertical' CG

Hey Rick:

  

 Way over my head.

  

 Do we have a problem with "vertical CG" on our  Kolbs?  I don't think I have ever encountered the phenomenon.

  

 john h

 mkIII

  

  

  

  

 [quote]    I do know that to say categorically it has    no effect is ridiculous on its face.

   



   Rick

 [b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jimh474(at)embarqmail.com
Guest

Posted: Wed Mar 11, 2009 2:55 pm Post subject: 'Vertical' CG

Y'all;



Now let me see this from that, All this vertical CG mess.



Seems to me we are strictly hypothetical in what a vertical CG does.



In referring to Bro John's MKIII, of where his fuel tank is located and the 

effect of a vertical CG, seems to me is not relevant at all.



Comparing a Cessna with the fuel tanks in the wings to The MKIII Classic 

with the fuel tank located on the center line is totally out of kilter. The 

fact is that John's fuel tank is located below the wing level and inboard of 

the cage. A Cessna has its fuel tanks outboard of the fuselage and at wing 

level. I can see where the fuel tanks being located outboard of the fuselage 

would make a difference in ground control, but not with the fuel tank 

located on the center line below the wings.



If the fuel tank was located above the wing some distance and outboard on 

the center of the fuselage, then I could see where the weight of fuel would 

effect ground handling.



So if vertical CG is so dang important, How do you compensate for it when 

you have a full tank of fuel or an almost empty tank.



Maybe I ain't edumacated enough to figger this out:)



Jim Hauck

russ(at)rkiphoto.com
Guest

Posted: Wed Mar 11, 2009 4:25 pm Post subject: 'Vertical' CG

Hoo boy, hope I haven't started another long-winded debate.

The location of the vertical CG is (i think) of small import in  

flying Kolbs. But it must exist, and be there.

Imagine if you will, having a 300-lb lead weight mounted between your  

tires. Then also imagine the same 300-lb weight in  the center  

section of the wing. or above it..

Would you expect a difference in the rate of roll while in the air?  

Yes, I think  so.

And on the ground, fast-taxiing and swerving? yes again, of course.

Anyone who's flown a Cessna on  wheels and then floats is well aware  

of this difference. But I think the tank placement on a Kolb makes so  

slight a difference it's maybe not even noticeable. A most forgiving  

and flexible wing/plane design.

We all should be grateful to Homer and his #1 test-pilot!

Anyway.

Russ Kinne

do not archive



On Mar 11, 2009, at 6:53 PM, Jim Hauck wrote:



 	  Quote: 	
		   



 Y'all;



 Now let me see this from that, All this vertical CG mess.



 Seems to me we are strictly hypothetical in what a vertical CG does.



 In referring to Bro John's MKIII, of where his fuel tank is located  

 and the effect of a vertical CG, seems to me is not relevant at all.



 Comparing a Cessna with the fuel tanks in the wings to The MKIII  

 Classic with the fuel tank located on the center line is totally  

 out of kilter. The fact is that John's fuel tank is located below  

 the wing level and inboard of the cage. A Cessna has its fuel tanks  

 outboard of the fuselage and at wing level. I can see where the  

 fuel tanks being located outboard of the fuselage would make a  

 difference in ground control, but not with the fuel tank located on  

 the center line below the wings.



 If the fuel tank was located above the wing some distance and  

 outboard on the center of the fuselage, then I could see where the  

 weight of fuel would effect ground handling.



 So if vertical CG is so dang important, How do you compensate for  

 it when you have a full tank of fuel or an almost empty tank.



 Maybe I ain't edumacated enough to figger this out:)



 Jim Hauck

jimh474(at)embarqmail.com
Guest

Posted: Wed Mar 11, 2009 4:37 pm Post subject: 'Vertical' CG

Russ;



Naw you ain't opened no can of worms.



But If I remember  the center of gravity is the center of mass as applied to 

a none moving object or a moving object, but in this case it is a none 

moving critter. So in reality, John's center of gravity is at the lower 

portion of his fuel tank and should just fine.



Jim Hauck

russ(at)rkiphoto.com
Guest

Posted: Wed Mar 11, 2009 5:08 pm Post subject: 'Vertical' CG

Jim,

Thanx reply. But the CG is the point that the aircraft rotates around  

-- unless i'm nuts (possible) that's the same, moving or not. The  

aircraft rotates in, any axis, around the CG. Only way to change the  

CG is to move weights around. Fuel tanks & passenger seats are often  

located on or near the CG, so no major changes when  they're full or  

empty. But you know all this.

And I'm sure no problem with John's or any other(?) Kolb .

Russ



On Mar 11, 2009, at 8:35 PM, Jim Hauck wrote:



 	  Quote: 	
		   



 Russ;



 Naw you ain't opened no can of worms.



 But If I remember  the center of gravity is the center of mass as  

 applied to a none moving object or a moving object, but in this  

 case it is a none moving critter. So in reality, John's center of  

 gravity is at the lower portion of his fuel tank and should just fine.



 Jim Hauck

slyck(at)frontiernet.net
Guest

Posted: Wed Mar 11, 2009 5:19 pm Post subject: 'Vertical' CG

Russ, maybe my Kolb needs a lead filled keel?

BB

do not archive

On 11, Mar 2009, at 9:06 PM, russ kinne wrote:

 	  Quote: 	

 Jim,

 Thanx reply. But the CG is the point that the aircraft rotates  

 around -- unless i'm nuts (possible) that's the same, moving or  

 not. The aircraft rotates in, any axis, around the CG. Only way to  

 change the CG is to move weights around. Fuel tanks & passenger  

 seats are often located on or near the CG, so no major changes  

 when  they're full or empty. But you know all this.

 And I'm sure no problem with John's or any other(?) Kolb .

 Russ

 On Mar 11, 2009, at 8:35 PM, Jim Hauck wrote:

> 

>

> Russ;

>

> Naw you ain't opened no can of worms.

>

> But If I remember  the center of gravity is the center of mass as  

> applied to a none moving object or a moving object, but in this  

> case it is a none moving critter. So in reality, John's center of  

> gravity is at the lower portion of his fuel tank and should just  

> fine.

>

> Jim Hauck

>

>

russ(at)rkiphoto.com
Guest

Posted: Wed Mar 11, 2009 5:33 pm Post subject: 'Vertical' CG

Maybe depends on how much lead there is in the pilot's keel??

do not archive!



On Mar 11, 2009, at 9:19 PM, robert bean wrote



 	  Quote: 	
		   



 Russ, maybe my Kolb needs a lead filled keel?

 BB

 do not archive

 On 11, Mar 2009, at 9:06 PM, russ kinne wrote:



> 

>

> Jim,

> Thanx reply. But the CG is the point that the aircraft rotates  

> around -- unless i'm nuts (possible) that's the same, moving or  

> not. The aircraft rotates in, any axis, around the CG. Only way to  

> change the CG is to move weights around. Fuel tanks & passenger  

> seats are often located on or near the CG, so no major changes  

> when  they're full or empty. But you know all this.

> And I'm sure no problem with John's or any other(?) Kolb .

> Russ

>

> On Mar 11, 2009, at 8:35 PM, Jim Hauck wrote:

>

>> 

>> <jimh474(at)embarqmail.com>

>>

>> Russ;

>>

>> Naw you ain't opened no can of worms.

>>

>> But If I remember  the center of gravity is the center of mass as  

>> applied to a none moving object or a moving object, but in this  

>> case it is a none moving critter. So in reality, John's center of  

>> gravity is at the lower portion of his fuel tank and should just  

>> fine.

>>

>> Jim Hauck

>>

>>

>>

>>

>

grantr

Joined: 12 Sep 2007
Posts: 217

Posted: Wed Mar 11, 2009 5:58 pm Post subject: Re: 'Vertical' CG

Gyro planes are sensitive to vertical cg vs thrustline. It really effects the stability of them. They really need centerline thrust to be considered stable. Many of the old ones like the original air commands and the RAFs have high thrustlines. The gyros can be flipped forward in flight due to an effect know as a power push over. That is where the thrust is so offset above the vertical cg that it pushes the nose of the gyroplane down thus getting air on top of the rotor and thats the end of that flight and pilot. Think of the vertical cg location as the pivot point as the thrust pushes the nose over.



high thrust lines coupled with  no horizontal stabs have contributed to many gyroplane fatal crashes. Even with the addition of H stab they are still not  stable but better than without.



I dont think fixed wing has a problem with vertical cg. If our thrust line gets to high we offset it with tail incidence. Plus our tail is a lot further back than a gyro.



The newer center line thrust gyros have some ground handling issue due to the mass being so high up.  Check out http://www.rotorflightdynamicsinc.com  Dominator or ultrawhite. Its  actually a low thrustline design which is very stable in flight. On the ground though it can be easily rolled over.



Airplane generally sit low so I dont see it as an issue there.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Mar 12, 2009 8:50 am Post subject: Re: 'Vertical' CG

Interesting Info Grant,



Which is exactly why I will never be flying a Gyro Plane      The performance is pretty incredible but having to depend on moving rotors to keep me from falling like a rock just does not sound fun...



I know John H spent many hours hanging in the air by rotors and lived through it, but there is a big difference between a helicopter developed by Bell Helicopters and flown for millions of hours, and a home made gyrocopter designed and tested by people with limited resources and funds !  



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

rlaird

Joined: 10 Jan 2006
Posts: 373
Location: Houston

Posted: Thu Mar 12, 2009 10:28 am Post subject: 'Vertical' CG

On Thu, Mar 12, 2009 at 11:50 AM, JetPilot <orcabonita(at)hotmail.com (orcabonita(at)hotmail.com)> wrote:

 	  Quote: 	
		   ..home made gyrocopter designed and tested by people with limited resources and funds !....

	




Yeah, sort of like a home made Kolb MkIII, built and tested by people with limited resources and funds !...   Oooo, that's scary!   

 

  -- R



  [quote][b]

_________________
~~~~~~~~~~~~~~~~~~~
Robert Laird
formerly: MkIIIc w/ 912ULS & Gyrobee
current: Autogyro Cavalon w/ 914ULS
Houston, TX area
http://www.Texas-Flyer.com

Ed in JXN

Joined: 24 Mar 2006
Posts: 122

Posted: Thu Mar 12, 2009 3:02 pm Post subject: 'Vertical' CG

Rick,

  

         Please  don't put words in my mouth.  No one said 'categorically it has no  effect'.  To an engineer, perhaps.  To a pilot, it's a moot  point.  Fore-and-aft CG change is of primary concern to aircraft, then  lateral, then last (and I would conjecture least) vertical. (We are  still discussing aircraft, not SUV's.) Never heard of an aircraft going  out-of-control due to displaced vertical CG.  You're correct in the  engineering sense, but waaay too concerned about something that's not even  touched on in general aviation texts.

         I will hand  it to you, I could not detect the handling difference in models of 172's,  so perhaps 3,000 hrs. of dual given hasn't properly prepared me.  Never had  a check airman bring it up in the CFI, CFI-AI, MEI, or ATP oral or  checkrides.  I should get my money back.  And I must've been sleeping  through all the and initial and recurrent training at FlightSafety Int'l. and  SimCom in the Cessna 400-series, King Air 200, 300, 350, Merlin IIIB, Piper  Cheyenne I & II, Citation I, II, V, Bravo,  obtained over 30-odd  years and 15,000+ hours.  The only vertical component available to me is  the seat height, and my comfort trumps the slight concern over handling  effect.  So vertical component is (A) never discussed, (B) something we  have little-to-no control over, and (C) of concern in only the most arcane  sense.

         Vertical CG  certainly exists, but is of concern when we have some control over  it.  With my RC planes, I can move components to change it, but in  full-size aircraft it's fixed.  If it's so windy that control becomes  a concern, I don't fly.

         I'll respond  BC in the future so's not to further bore our Kolb brothers and  sisters.

  

 Ed in JXN

 MkII/503

 [quote]   ---

dcreech3(at)hotmail.com
Guest

Posted: Thu Mar 12, 2009 4:25 pm Post subject: 'Vertical' CG

If I may add a humble point: the vertical CG affects the pitch axis C too C doesn't it?  I've always assumed that the high CG of my Firestar II (resulting mainly from the engine way up there) is a major factor in its tendency to nose over if not handled carefully in some situations. 

  

 Lee

 

 

  From: edchmiel(at)mindspring.com

To: kolb-list(at)matronics.com

Subject: Re: Re: 'Vertical' CG

Date: Thu C 12 Mar 2009 18:56:08 -0400



    Rick C

  

         Please don't put words in my mouth.  No one said 'categorically it has no effect'.  To an engineer C perhaps.  To a pilot C it's a moot point.  Fore-and-aft CG change is of primary concern to aircraft C then lateral C then last (and I would conjecture least) vertical. (We are still discussing aircraft C not SUV's.) Never heard of an aircraft going out-of-control due to displaced vertical CG.  You're correct in the engineering sense C but waaay too concerned about something that's not even touched on in general aviation texts.

         I will hand it to you C I could not detect the handling difference in models of 172's C so perhaps 3 C000 hrs. of dual given hasn't properly prepared me.  Never had a check airman bring it up in the CFI C CFI-AI C MEI C or ATP oral or checkrides.  I should get my money back.  And I must've been sleeping through all the and initial and recurrent training at FlightSafety Int'l. and SimCom in the Cessna 400-series C King Air 200 C 300 C 350 C Merlin IIIB C Piper Cheyenne I & II C Citation I C II C V C Bravo C  obtained over 30-odd years and 15 C000+ hours.  The only vertical component available to me is the seat height C and my comfort trumps the slight concern over handling effect.  So vertical component is (A) never discussed C (B) something we have little-to-no control over C and (C) of concern in only the most arcane sense.

         Vertical CG certainly exists C but is of concern when we have some control over it.  With my RC planes C I can move components to change it C but in full-size aircraft it's fixed.  If it's so windy that control becomes a concern C I don't fly.

         I'll respond BC in the future so's not to further bore our Kolb brothers and sisters.

  

 Ed in JXN

 MkII/503

 [quote] ---

slyck(at)frontiernet.net
Guest

Posted: Thu Mar 12, 2009 6:30 pm Post subject: 'Vertical' CG

That is more directly a function of center of thrust, referenced to either the wing or center of drag whichever most concerns you.  Any vertical CG effect caused by the engine location would have little influence on the

nose down with power tendency.  -which, BTW,I pretty much automatically compensated for by the 

time I had an hour on my MkIII.

It turns out to be a beneficial effect for me anyway during landing.  Old antique, high wing tractor taildraggers exhibit

quite a nose up pitch with power added at the last second, sometimes to your detriment.

The Kolb properly points you in the right direction 

BB

On 12, Mar 2009, at 8:24 PM, LEE CREECH wrote:

[quote]If I may add a humble point: the vertical CG affects the pitch axis, too, doesn't it?  I've always assumed that the high CG of my Firestar II (resulting mainly from the engine way up there) is a major factor in its tendency to nose over if not handled carefully in some situations. 

 

Lee



 

From: edchmiel(at)mindspring.com (edchmiel(at)mindspring.com)

To: kolb-list(at)matronics.com (kolb-list(at)matronics.com)

Subject: Re: Re: 'Vertical' CG

Date: Thu, 12 Mar 2009 18:56:08 -0400



Rick,

 

        Please don't put words in my mouth.  No one said 'categorically it has no effect'.  To an engineer, perhaps.  To a pilot, it's a moot point.  Fore-and-aft CG change is of primary concern to aircraft, then lateral, then last (and I would conjecture least) vertical. (We are still discussing aircraft, not SUV's.) Never heard of an aircraft going out-of-control due to displaced vertical CG.  You're correct in the engineering sense, but waaay too concerned about something that's not even touched on in general aviation texts.

        I will hand it to you, I could not detect the handling difference in models of 172's, so perhaps 3,000 hrs. of dual given hasn't properly prepared me.  Never had a check airman bring it up in the CFI, CFI-AI, MEI, or ATP oral or checkrides.  I should get my money back.  And I must've been sleeping through all the and initial and recurrent training at FlightSafety Int'l. and SimCom in the Cessna 400-series, King Air 200, 300, 350, Merlin IIIB, Piper Cheyenne I & II, Citation I, II, V, Bravo,  obtained over 30-odd years and 15,000+ hours.  The only vertical component available to me is the seat height, and my comfort trumps the slight concern over handling effect.  So vertical component is (A) never discussed, (B) something we have little-to-no control over, and (C) of concern in only the most arcane sense.

        Vertical CG certainly exists, but is of concern when we have some control over it.  With my RC planes, I can move components to change it, but in full-size aircraft it's fixed.  If it's so windy that control becomes a concern, I don't fly.

        I'll respond BC in the future so's not to further bore our Kolb brothers and sisters.

 

Ed in JXN

MkII/503

[quote]---

dcreech3(at)hotmail.com
Guest

Posted: Thu Mar 12, 2009 6:57 pm Post subject: 'Vertical' CG

I was actually thinking of the time I was taxiing down a rather steep hill (shortcut from runway to barn) at about 1 mph with the engine idling C when the world slowly rotated around me and the plane put its nose on the ground.  From then on I went the long way around.  

  

 Lee

 

  From: slyck(at)frontiernet.net

Subject: Re: Re: 'Vertical' CG

Date: Thu C 12 Mar 2009 22:27:58 -0400

To: kolb-list(at)matronics.com



That is more directly a function of center of thrust C referenced to either the wing or center of drag whichever  most concerns you.  Any vertical CG effect caused by the engine location would have little influence on the

 nose down with power tendency.  -which C BTW CI pretty much automatically compensated for by the 

 time I had an hour on my MkIII.

 It turns out to be a beneficial effect for me anyway during landing.  Old antique C high wing tractor taildraggers exhibit

 quite a nose up pitch with power added at the last second C sometimes to your detriment.

 The Kolb properly points you in the right direction 

 BB

 



   On 12 C Mar 2009 C at 8:24 PM C LEE CREECH wrote:

  	  Quote: 	
		  If I may add a humble point: the vertical CG affects the pitch axis C too C doesn't it?  I've always assumed that the high CG of my Firestar II (resulting mainly from the engine way up there) is a major factor in its tendency to nose over if not handled carefully in some situations. 

 

Lee



 

        

	




Windows Live™ Groups: Create an online spot for your favorite groups to meet. Check it out.  [quote][b]

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Fri Mar 13, 2009 12:52 pm Post subject: Re: 'Vertical' CG

[quote="rlaird"]

Yeah, sort of like a home made Kolb MkIII, built and tested by people with limited resources and funds !...ï¿½ï¿½ Oooo, that's scary!ï¿½ï¿½ 

 

ï¿½ -- R



   	  Quote: 	
		  [b] 	




Yes, its true of our Kolbs also,



But I feel much better with big aluminum tube spars, ribs and fabric,  Even I can get this right !  Hanging by a whirling mass of very highly stressed rotor components, bearings, and linkages just seems more problematic than the big aluminum tube spar we hang by.   I am just as happy to leave the rotors to Bell Helicopter  



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Display posts from previous:

	Matronics Email Lists Forum Index -> Kolb-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum