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

Level Aft CG...

Matronics Email Lists Forum Index -> Kolb-List

View previous topic :: View next topic

Author Message

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Tue May 09, 2006 4:46 am Post subject: Level Aft CG...

I need the aft CG limit (preferably the distance from datum, fixed point,

etc.) and the leveling points on an early Firestar...



I'm installing floats and I need to engineer the rigging...



Thanx...



David

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

Steve Boetto

Joined: 11 Jan 2006
Posts: 365

Posted: Tue May 09, 2006 5:07 am Post subject: Level Aft CG...

In a message dated 5/9/2006 8:47:44 A.M. Eastern Standard Time,  

david(at)davidlehman.net writes:






I need the aft CG limit (preferably the  distance from datum, fixed point,

etc.) and the leveling points on an early  Firestar...



I'm installing floats and I need to engineer the  rigging...



Thanx...



David





David,

 

After flying the Firefly on floats now for a year, Bryan Melborn and I have  

found that there may be more critical issues on position of floats on a Kolb  

other than CG.  We picked a point for what would be about midpoint of the  CG 

range for the Firefly and placed it about an inch or so forward of the step.  

This is common practice for most float installations. On a normal full power  

takeoff more back pressure is required than would seem right. At reduced  

throttle less back pressure is required. At SnF this year Dick Rayhill commented  

that due to the high thrust line it may be better to shift the CG aft in 

regard  to the step. This would compensate for  the high thrust line and increase  

takeoff performance.

Unfortunately, it would be difficult to test this on FF #007. On the  Firefly 

we are building from scratch we will move the CG aft.

Despite this minor tweaking we are very please with the handling of FF#007  

on floats. Due to it's light weight and other Kolb traits it handles anything  

that you throw at it like a Champ.

 

Steve Boetto

FF#007

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Tue May 09, 2006 6:28 am Post subject: Re: Level Aft CG...

Thanx Steve...



These are the floats I sent you a picture of awhile back...



I had received this information from a Kitfox owner, "5 to 6 degrees (nose up) between the fuselage leveling line and the top of the float.  I used the door frame on the kitfox....you need to know where the fuselage is level.  This will make your floats slightly nose down when you are in flight, which is OK.  I do know that if you don't have at least this much difference, you won't be able to get up on the step.   Don't get carried away with this, because your tail will drag in the water when you try to climb up on the step. 5 to 6 degrees is the number that works!

 

Step needs to be 4 to 6 inches AFT of your MAX AFT CG, so that you can rotate around it, otherwise you can't get the nose up to takeoff position.", and I thought I'd use that as a starting point...



There's not a lot of information out there on proper float placement...



The floats are new, but I think the rigging is for a  two-place Quicksilver, so it's all "by gosh, by golly" at this stage of the game...



Thanx again...



David



do not archive

CIMG0804.JPG

Description:

Filesize:

120.27 KB

Viewed:

357 Time(s)

CIMG0803.JPG

Description:

Filesize:

113.04 KB

Viewed:

355 Time(s)

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

Ed in JXN

Joined: 24 Mar 2006
Posts: 122

Posted: Tue May 09, 2006 12:18 pm Post subject: Level Aft CG...

Steve,



        What else do you throw at it, besides the Champ??  ;^)



Ed in JXN



Do not archive.



---

ElleryWeld(at)aol.com
Guest

Posted: Tue May 09, 2006 1:33 pm Post subject: Level Aft CG...

20% to 37% is the CG range on a early Firestar 10" to 18 3/4" back from the 

leading edge of your wing is where you want to be to stay in the CG range



involved in the same process getting my floats mounted up



Ellery in Early Firestar headed to the lake some time soon



do not archive

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Tue May 09, 2006 1:46 pm Post subject: Level Aft CG...

Thanx Ellery...



Seems to be a lot of "smoke and mirrors" to determining float placement...

Steve B has already made a lot of progress and I think we can learn from

him...



DVD



do not archive

On 5/9/06, ElleryWeld(at)aol.com <ElleryWeld(at)aol.com> wrote:

 	  Quote: 	
		  

 



 20% to 37% is the CG range on a early Firestar 10" to 18 3/4" back from

 the

 leading edge of your wing is where you want to be to stay in the CG range



 involved in the same process getting my floats mounted up



 Ellery in Early Firestar headed to the lake some time soon



 do not archive

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Tue May 09, 2006 1:51 pm Post subject: Re: Level Aft CG...

 	  ElleryWeld(at)aol.com wrote: 	
		  20% to 37% is the CG range on a early Firestar 10" to 18 3/4" back from the 

leading edge of your wing is where you want to be to stay in the CG range



involved in the same process getting my floats mounted up



Ellery in Early Firestar headed to the lake some time soon



do not archive 	




Ellery...



I forgot to ask, what's the level point(s) on the early Firestar...



Thanx...



DVD



do not archive

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

jdm(at)wideworld.net
Guest

Posted: Tue May 09, 2006 3:59 pm Post subject: Level Aft CG...

I'm 20.7 back from the LE and it seems to fly ok even with engine off?





---

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Tue May 09, 2006 4:13 pm Post subject: Re: Level Aft CG...

 	  jdm(at)wideworld.net wrote: 	
		  I'm 20.7 back from the LE and it seems to fly ok even with engine off?--- 	




Thanx JDM...



I'm assuming that's your empty weight CG...



DVD

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

Steve Boetto

Joined: 11 Jan 2006
Posts: 365

Posted: Tue May 09, 2006 4:42 pm Post subject: Level Aft CG...

In a message dated 5/9/2006 10:35:13 A.M. Eastern Standard Time,  

david(at)davidlehman.net writes:



"5 to 6  degrees (nose up) between the fuselage leveling line and the top of 

the  float.  I used the door frame on the kitfox....you need to know where the 

 fuselage is level.  This will make your floats slightly nose down when  you 

are in flight, which is OK.  I do know that if you don't have at  least this 

much difference, you won't be able to get up on the  step.   Don't get carried 

away with this, because your tail will  drag in the water when you try to 

climb up on the step. 5 to 6 degrees is the  number that works!



Step needs to be 4 to 6 inches AFT of your MAX AFT  CG,

David,  6 degrees sounds about right on the kolb but your aft CG  figure 

sounds really FAR back. 

 

steve

Steve Boetto

Joined: 11 Jan 2006
Posts: 365

Posted: Tue May 09, 2006 4:50 pm Post subject: Level Aft CG...

In a message dated 5/9/2006 4:19:48 P.M. Eastern Standard Time,  

edchmiel(at)mindspring.com writes:



Steve,



What else do you throw at it,  besides the Champ??  ;^)



Ed in JXN



Do not  archive.



Sometimes afew foul words when it wont land perfectly smooth every time  (-:

 

No really, it is the most forgiving plane I have flown, my UL skills just  

need to get better

 

steve

ElleryWeld(at)aol.com
Guest

Posted: Tue May 09, 2006 5:18 pm Post subject: Level Aft CG...

Really did you do the weight and balance with the plane in the flying 

attitude 



                         Ellery

jdm(at)wideworld.net
Guest

Posted: Tue May 09, 2006 5:22 pm Post subject: Level Aft CG...

No that's with me in it and no fuel.



 	  Quote: 	
		  



 jdm(at)wideworld.net wrote:

> I'm 20.7 back from the LE and it seems to fly ok even with engine off?---

 Thanx JDM...



 I'm assuming that's your empty weight CG...



 DVD



 --------

  http://photobucket.com/albums/e327/N446/



 Do not spin this aircraft. If the aircraft does enter a spin it will 

 return to earth without further attention on the part of the aeronaut.



 first handbook issued with the Curtis-Wright flyer.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=33717#33717

jdm(at)wideworld.net
Guest

Posted: Tue May 09, 2006 5:33 pm Post subject: Level Aft CG...

If you are asking me, yes.

---

ElleryWeld(at)aol.com
Guest

Posted: Tue May 09, 2006 5:34 pm Post subject: Level Aft CG...

Are you sure thats where your CG is that really sounds to far aft  Have you 

ever played with stalls with it (which I would not recomend at this point) if 

you havent already, after I added the full swivel tail wheel I didnt feel 

comfortable trying any stalls it just felt tail heavy but I did a new weight & 

balance and I am only 1 1/2" from my aft CG location 

my weight &balance is with Full fuel  10 gallons  and me in it 



Ellery

do not archive

jdm(at)wideworld.net
Guest

Posted: Tue May 09, 2006 5:57 pm Post subject: Level Aft CG...

I did some power off stall.  It breaks clean with no tendency to drop a 

wing.  I know it seems far back.  I should probably double-check my numbers.



Also I have to bungie the stick back to keep the nose up while cruising. 

Even at idle it needs slight back pressure.  It doesn't feel tail-heavy, 

which is why I need to do it again and check my numbers

---

David.Lehman

Joined: 10 Jan 2006
Posts: 265
Location: "Lovely" Fresno CA

Posted: Wed May 10, 2006 6:32 am Post subject: Level Aft CG...

Thanx Steve...



Lot's of numbers floating (pun intended) around for placement...



Ellery gave me some numbers that he's using and I found this site with

discussion regarding placement:

http://www.ultralightfloats.com/instructions.htm ...



I forgot to measure the width of my floats before I came to the office this

morning, but I'm guessing they're around 18" wide...



It's supposed to be 90 degrees here in "Lovely" Fresno today and the water'=

s

inviting, I'm getting real anxious to float the Firestar...



DVD



do not archive

On 5/9/06, N27SB(at)aol.com <N27SB(at)aol.com> wrote:

 	  Quote: 	
		  

 

 In a message dated 5/9/2006 10:35:13 A.M. Eastern Standard Time,

 david(at)davidlehman.net writes:



 "5 to 6  degrees (nose up) between the fuselage leveling line and the top

 of

 the  float.  I used the door frame on the kitfox....you need to know wher=

e
	


 	  Quote: 	
		   the

 fuselage is level.  This will make your floats slightly nose down

 when  you

 are in flight, which is OK.  I do know that if you don't have at  least

 this

 much difference, you won't be able to get up on the  step.   Don't get

 carried

 away with this, because your tail will  drag in the water when you try to

 climb up on the step. 5 to 6 degrees is the  number that works!



 Step needs to be 4 to 6 inches AFT of your MAX AFT  CG,

 David,  6 degrees sounds about right on the kolb but your aft CG  figure

 sounds really FAR back.



 steve

_________________
ô¿ô

"Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute."

--- George Bernard Shaw

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