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The Numbers Don't Lie
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John Williamson

Joined: 10 Jan 2006
Posts: 146
Location: Arlington, TX

Posted: Mon Mar 24, 2008 5:08 pm Post subject: The Numbers Don't Lie

All this speculation on what and how the Xtra does or will perform made me go flying today and get some numbers.



Pressure Altitude: 2500 feet, 52 degrees F.

5480 rpm: 90 kts

5000 rpm: 80 kts

4500 rpm: 70 kts

4000 rpm: 57 kts



The airplane is rigged to the factory specs.

do not archive

_________________
John Williamson
Arlington, TX

Kolbra, 912ULS, 1640 hours
http://home.tx.rr.com/kolbrapilot

ElleryWeld(at)aol.com
Guest

Posted: Mon Mar 24, 2008 5:53 pm Post subject: The Numbers Don't Lie

Thanks John W  that is the kind of info I  was looking for that will help me make my mind up if I can get more from someone  else to compare it with

  some day it might warm up here so I can enjoy a  day of  flying my self 

  

 Ellery from Maine

  do not archive 

  if you dont think America is falling apart   take a drive across Maine  it will change your mind real quick ,The roads  are terrible here 

  

  In a message dated 3/24/2008 8:11:35 P.M. Eastern Standard Time,  kolbrapilot1(at)tx.rr.com writes:

  	  Quote: 	
		  -->    Kolb-List message posted by: "John Williamson"    <kolbrapilot1(at)tx.rr.com>



All this speculation on what and how the    Xtra does or will perform made me go flying today and get some    numbers.



Pressure Altitude: 2500 feet, 52 degrees F.

5480 rpm: 90    kts

5000 rpm: 80 kts

4500 rpm: 70 kts

4000 rpm: 57 kts



The    airplane is rigged to the factory specs.

do not    archive



--------

John Williamson

Arlington, TX



Kolbra,    912ULS, 1580    hours

http://home.tx.rr.com/kolbrapilot





Read this topic    online    here:



http://forums.matronics.com/viewtopic.php?p=172396#172396

	




Create a Home Theater Like the Pros. Watch the video on AOL Home.

  [quote][b]

NeilsenRM(at)comcast.net
Guest

Posted: Mon Mar 24, 2008 7:10 pm Post subject: The Numbers Don't Lie

Hey John W



Not everyone knows that you fly a 100HP Rotax powered Kolbra. I assume the 

figures were in that bird. It would drive these guys crazy trying to match 

those numbers in a Xtra.



Rick Neilsen

Redrive VW powered MKIIIC



---

John Williamson

Joined: 10 Jan 2006
Posts: 146
Location: Arlington, TX

Posted: Mon Mar 24, 2008 7:26 pm Post subject: Re: The Numbers Don't Lie

Hi Rick and All,



Of course those numbers are for my Kolbra! 



I tell everyone what I fly in my signature block on every post.

do not archive

_________________
John Williamson
Arlington, TX

Kolbra, 912ULS, 1640 hours
http://home.tx.rr.com/kolbrapilot

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Tue Mar 25, 2008 4:56 am Post subject: Re: The Numbers Don't Lie

Before I bent the early FS, I had the following numbers.

Early FS, no wheel pants, no streamlined struts, empty wt. 362 lb., 447, 40hp

Power Fin, 2-blade, 62" long, pitched for 6500 rpm WOT S&L



2000' Density Altitude

Note these are Indicated Airspeeds with unknown TAS



IAS(mph)/   RPM/                           Fuel Burn Estimate (gph)

80/             6,500                          

69/             5,700 (~75% power)/    3.0 

64/             5,600 (~65%)/              2.6

59/             5,300 (~55%)/              2.2

53/             4,900 (~45%)/              1.8



do not archive

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Tue Mar 25, 2008 5:59 am Post subject: Re: The Numbers Don't Lie

Those are impressive numbers John,  I dont think a MK III will ever match that, just to much Xtra drag with the wide fuselage.   



Is 5480 Max Thottle ?  What RPM do you get on climbout ?   What are you stall speeds like ?



BTW 90 KTS = 103.7 MPH !!!     How does it feel at that speed ?  



Mike

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

Kolb MK-III Xtra, 912-S

travis(at)tnkolbaircraft.
Guest

Posted: Tue Mar 25, 2008 6:09 am Post subject: The Numbers Don't Lie

> Pressure Altitude: 2500 feet, 52 degrees F.

 	  Quote: 	
		   5480 rpm: 90 kts

 5000 rpm: 80 kts

 4500 rpm: 70 kts

 4000 rpm: 57 kts



 The airplane is rigged to the factory specs.

 > John Williamson
	


John W:



Ain't fair!



How come my chubby little mkIII won't fly as fast as your skinny little 

Kolbra?



Reckon my horizontal stabilizer is mounted upside down?



Getting ready to do some more flying in the new X before the forecast winds 

arrive in London.  We are looking for 20 to 30 mph gusting to 40.  Maybe I 

can try some cross wind landings this afternoon.  



Testing is progressing.  We plan to mount the droop tips tomorrow.  If I can 

get some calm air I can come up with some numbers without the tips.  This 

block of time has not been conducive to flying.



john h

mkIII

Labhart Field, KY - 24F climbing through 31F

slyck(at)frontiernet.net
Guest

Posted: Tue Mar 25, 2008 6:33 am Post subject: The Numbers Don't Lie

John, how are the tips configured now?  stock kolb or chopped end?

We need apples to apples.  -Also a flat plate fence would be  

interesting.

Good luck with the breezes.

BB

do not archive

On 25, Mar 2008, at 10:05 AM, Travis Brown (Kolb Aircraft) wrote:

 	  Quote: 	

 <travis(at)tnkolbaircraft.com>

 > Pressure Altitude: 2500 feet, 52 degrees F.

> 5480 rpm: 90 kts

> 5000 rpm: 80 kts

> 4500 rpm: 70 kts

> 4000 rpm: 57 kts

>

> The airplane is rigged to the factory specs.

 > John Williamson

 John W:

 Ain't fair!

 How come my chubby little mkIII won't fly as fast as your skinny  

 little Kolbra?

 Reckon my horizontal stabilizer is mounted upside down?

 Getting ready to do some more flying in the new X before the  

 forecast winds arrive in London.  We are looking for 20 to 30 mph  

 gusting to 40.  Maybe I can try some cross wind landings this  

 afternoon.  

 Testing is progressing.  We plan to mount the droop tips tomorrow.   

 If I can get some calm air I can come up with some numbers without  

 the tips.  This block of time has not been conducive to flying.

 john h

 mkIII

 Labhart Field, KY - 24F climbing through 31F

travis(at)tnkolbaircraft.
Guest

Posted: Tue Mar 25, 2008 7:52 am Post subject: The Numbers Don't Lie

> John, how are the tips configured now?  stock kolb or chopped end?

 > BB

Bob B:



The wing section is 13 feet long and chopped off at the end.  It is the same 

length as the FSII wing section including the bowtip.  With the new droop 

tips, the wing section will be about 14 feet.



I just landed from my morning flight.  Air is cold, 35F, and wind is brisk.



The X has 20 and 45 degrees of flaps.  She stalled at 32 mph IAS and 30 mph 

IAS at 3,000 feet ASL.



This airplane is more a rudder airplane than any other Kolb I have flown, 

yet it flies and handles much like all the other models.



I did some maximum climbs this morning.  This airplane climbs at a near 

vertical attitude.  It feels and looks nearly vertical when it is screwing 

its way into the air.  At one point the engine quit while climbing.  I have 

never had this happen in a Kolb.



I have a much better atttitude about this X than any of the others I have 

flown.  Might be because of changes between the models and the fact that I 

have assisted in tweaking this one to fly the way I like them.



john h

mkIII

Labhart Field, KY

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Tue Mar 25, 2008 9:25 am Post subject: Re: The Numbers Don't Lie

For those who care, here is one theoretical comparison of the Droop Tips vs. Hoerner style tips (a la Possums).



http://selair.selkirk.bc.ca/aerodynamics1/Drag/Page8.html



Go to the link and page down to see the brief bits on each. 



FWIW, I've owned airplanes with both types of wing tips. I've flown Cherokees with the standard Hershey bar wing and owned one with the Hoerner type wing tips. The Hoerner wing tips definitely made the slow speed handling a lot better in all respects including a little slower stall speed, at least in the air but don't know about in ground effect 'cuz I don't watch the ASI when in ground effect.



I also owned a Titan Tornado with the droop tips and it would climb at incredible angles of attack, even with the short 20' wing with 80 hp Rotax. Its stall behavior was completely benign and quite slow speed for such a small wing.



What I've read, but can't find now, is that both types will improve slow speed handling and reduce stall speed (increase critical angle of attack). In that same article I can't find now, it said the primary difference between the two is that typically the Droop Tips cause a more abrupt stall. That was not the case in my one airplane experience. 



do not archive

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

John Williamson

Joined: 10 Jan 2006
Posts: 146
Location: Arlington, TX

Posted: Tue Mar 25, 2008 9:31 am Post subject: Re: The Numbers Don't Lie

 	  JetPilot wrote: 	
		  Those are impressive numbers John,  I dont think a MK III will ever match that, just to much Xtra drag with the wide fuselage.   

Is 5480 Max Thottle ?  What RPM do you get on climbout ?   What are you stall speeds like ?

BTW 90 KTS = 103.7 MPH !!!     How does it feel at that speed ?  

Mike 	




Hi All,



Yes 5480 rpm is full throttle, I couldn't prop it to hit 5500 rpm exactly.



Climbout rpm is dependent on airspeed and angle of climb so it is not very relevant. Climb rate will vary from 500 fpm to 1400 fpm depending on what is in the pattern behind and in front of me.



Stall speed is a good reference number for some I guess. The only three times I see the stall speed is accellerating thru it with the wheels on the runway, decelerating back thru it with the wheels on the runway and when actually doing stalls at least 1500 feet above the ground.



I see 96 kts (110.4751 mph) on almost every flight. It feels like a Kolb.



I also should have said that my speeds are calibrated airspeeds, not just indicated airspeeds. If you have an error in your IAS, you should adjust it out or make a calibration card to go beside your IAS indicator. For the folks that like TAS, I had included the PA and Temp so you can figure the TAS.



do not archive

_________________
John Williamson
Arlington, TX

Kolbra, 912ULS, 1640 hours
http://home.tx.rr.com/kolbrapilot

Last edited by John Williamson on Tue Mar 25, 2008 10:20 am; edited 1 time in total

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Tue Mar 25, 2008 9:37 am Post subject: Re: The Numbers Don't Lie

[quote="travis(at)tnkolbaircraftI did some maximum climbs this morning.  This airplane climbs at a near 

vertical attitude.  It feels and looks nearly vertical when it is screwing 

its way into the air.  At one point the engine quit while climbing.  I have 

never had this happen in a Kolb.



john h

mkIII

Labhart Field, KY[/quote]



That is incredible, but what caused the engine out ?  Could it be that the climb was so steep that it the fuel in the carb bowls was to far from level, or the fuel moved back in the tank away from where it is picked up ?



Mike

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

Kolb MK-III Xtra, 912-S

travis(at)tnkolbaircraft.
Guest

Posted: Tue Mar 25, 2008 10:49 am Post subject: The Numbers Don't Lie

> That is incredible, but what caused the engine out ?  Could it be that 

the climb was so steep that it the fuel in the carb bowls was to far from 

level, or the fuel moved back in the tank away from where it is picked up ?

 	  Quote: 	
		  

 Mike


	


Mike B:



First question:  Probably fuel starvation from the floats closing the float 

valves.



Flew again later and could not get the X to climb like it did early this 

morning.  Climbed like any other Kolb, stick full back, climbing until the 

prop started cavitating, but still climbing.



john h

mkIII

Labhart Field, KY

mdnanwelch7(at)hotmail.co
Guest

Posted: Tue Mar 25, 2008 11:14 am Post subject: The Numbers Don't Lie

 	  Quote: 	
		   I have a much better attitude about this X than any of the others I have 

 flown. Might be because of changes between the models and the fact that I 

 have assisted in tweaking this one to fly the way I like them.

 

 john h

 mkIII

 Labhart Field, KY

  
	


 

  John, 

  

   You crack me up!!  You're sounding like the guy that just got back from test-driving

 a 2009 Pickup.....and saying "hey, can I get this in metalic silver.   5 more minutes, and you're hooked!!

 You may as well make a $12,000 donation to TNK right now!   ha ha ha ha!   (Don't be mad at me, I'm just

 funnin' ya!)

  

   I have a little favor to ask of you.  Since you get the impression that this new MkIIIXtra fly fairly well, would it be possible for you to take a reading of the main wings' and the hor. stabs incidences, and the boom tube.  No need to go to any elaborate measures, just a quick reading of the bottom of the wing, and the top of the stabs, and the boom tube.  That way, I can set my boom tube to your reading, and then set my incidence the same the plane you're flying.  I'll bring you a cold beer at Monument Valley.  Thanks

  

 Mike Welch

  

  

  

   

Watch “Cause Effect,” a show about real people murce=text_watchcause' target='_new'>Learn more.  [quote][b]

dhkey(at)msn.com
Guest

Posted: Tue Mar 25, 2008 2:40 pm Post subject: The Numbers Don't Lie

Don't click this link if you have dial up.

  

 Here's a great photo of JohnW's skinny plane

 http://home.tx.rr.com/kolbrapilot/index_files/IMG_0530.JPG

  [quote][b]

dhkey(at)msn.com
Guest

Posted: Tue Mar 25, 2008 2:42 pm Post subject: The Numbers Don't Lie

Sorry I found that photo on John's site but it doesn't look like his plane. [quote][b]

John Williamson

Joined: 10 Jan 2006
Posts: 146
Location: Arlington, TX

Posted: Tue Mar 25, 2008 2:58 pm Post subject: Re: The Numbers Don't Lie

 	  dhkey(at)msn.com wrote: 	
		  Sorry I found that photo on John's site but it doesn't look like his plane. 	




That photo is one I took looking directly up the tail of a Titan with the fuselage blocking the sun.  Hence, one of many of my favorite photos I have taken.

do not archive

_________________
John Williamson
Arlington, TX

Kolbra, 912ULS, 1640 hours
http://home.tx.rr.com/kolbrapilot

ez(at)embarqmail.com
Guest

Posted: Tue Mar 25, 2008 6:11 pm Post subject: The Numbers Don't Lie

Don't click this link if you want to see a kolbra.

On Mar 25, 2008, at 6:34 PM, David Key wrote: 	  Quote: 	
		  Don't click this link if you have dial up.

 

Here's a great photo of JohnW's skinny plane

http://home.tx.rr.com/kolbrapilot/index_files/IMG_0530.JPG

 	  Quote: 	
		  http://www.matronics.com/Navigator?Kolb-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/contribution



	


	


 [quote][b]

John Bickham

Joined: 10 Jan 2006
Posts: 170
Location: St. Francisville, LA

Posted: Tue Mar 25, 2008 6:30 pm Post subject: Re: The Numbers Don't Lie

One of my most favorite things is flying XC trips with John Williamson.  Always fun and always learn something new.  The only negative is, while I'm peddling as fast as I can, he and the Kolbra are zooming and diving all over the place.  He can make a pit stop on a 2 hour leg and still climb back up with me in a matter of minutes.



Still fun, just a little aggravating in a good way.

_________________
Thanks too much,

John Bickham
Mark III-C w/ 912UL
St. Francisville, LA

I know many pilots and a few true aviators. There is a distinct difference that I have the greatest respect for.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Mar 26, 2008 6:20 am Post subject: Re: The Numbers Don't Lie

John Willamsons Web Site and videos are great.  Even if you have a slow connection, its worth the time it takes to load the pictures and watch the videos.



Mike

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

Kolb MK-III Xtra, 912-S

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