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slyck(at)frontiernet.net
Guest

Posted: Fri Sep 17, 2010 5:51 am Post subject: kolb stall

I think this subject is deserving of a new thread.

We all have different brains and bodies and perceive and react differently.  That's why some are natural athletes

and some aren't.  (I'm in the aren't category) .   For some, who need a board alongside the head to convince them,

have weak sensory inputs, or very limited flight experience,  will need a thorough examination of such things as

stall and aileron response during the first flight.

What works for some may not for others.  Personally I prefer to gently get to know the airplane in stages and get a feel

for it before experimenting too far into the unknown.  I don't go to altitude and do a stall series on the first flight.

I don't do maxie bank turns.   I climb to a decent altitude within a safe distance of an emergency put down and check

straight and level.  I peek at the oil pressure and temps.  I make a couple gentle turns.

I then head back to terra firma and try to make an acceptable landing.  

Get out, look at what dropped off.

Pop open a brewski and pat meself on the back.



BTW, I don't think I have ever done a real stall series on my MkIII.  

flies just fine.

BB



ps, had another of my yearly mechanical failures a couple weeks ago.  If interested I'll relate it after

youze guyz get done gnawing on this post.

jvanlaak(at)aol.com
Guest

Posted: Fri Sep 17, 2010 6:09 am Post subject: kolb stall

Folks,

 

 I have been trying to decide when/if to contribute to this discussion and finally couldn't hold back any longer.  I love Kolbs, having built a Firestar I in the late 80's and flown it happily for about 10 years.  Great airplane.  I have also built/rebuilt half a dozen other planes from a Talon XP to a Midget Mustang.  And over 40 years I have flown about 140 types from a Hummer to the F-106 and F-18.  Loved almost all of them.

 

 But experimental homebuilt airplanes are in a class of their own.  Many of them do not comply with normal standards for control harmony, rigging, or even control placement.  Some of them are built straight and true and some are an accident waiting to happen.  I once was asked to test fly a Mitchell P-38 and as it accelerated down the field it needed more and more right rudder and left aileron.  I aborted at about 20 mph as I seemed to be reaching the limit of control.  The airplane was junked for parts.  On another occasion I was test flying a Rans S-12 for a guy only to find that the CG was so far back the nose would keep going up on its own when you started to flare.  By the way, he had falsified the weight and balance to make it look right.  I eventually bought the airplane and put 40 lbs of lead in the nose to make it fly right solo.  No lead needed with two adults, but still needed 20 lb when flying with a kid.  And a Bushby Mustang II was so badly rigged that even with perfect control handling (I was at my prime at the time) it would roll into 60 degrees of bank in a stall and require the nose 20 degrees below the horizon to recover.  I had been thinking of buying it but that did not last long.  It had a beautiful paint job, interior and panel from the Space Shuttle, looked like an Oshkosh award winner, but it was a death trap.

 

 So please don't argue about the way the Kolb stalls.  Each one is different.  Yours might be a perfect lady or the devil incarnate but it does not tell you what the next one will be.  Incidentally about a year ago I flew a Mark IIIX thinking I might like to buy it but it was all messed up.  Got it back on the ground OK but did not enjoy it one bit, and that is the strongest thing about Kolbs - the sheer joy of being in the air with one.  Ended up with a Rans S-7 which is a nice plane but no Kolb.

 

 Jim Van Laak

    

  

     

  

    

     

  

     

  

    --

Ralph B

Joined: 14 Apr 2007
Posts: 367
Location: Mound Minnesota

Posted: Fri Sep 17, 2010 6:39 am Post subject: Re: kolb stall

The simple way not to stall on landing is to carry airspeed. During calm conditions the plane can be on the edge of a stall and land ok, if there are no thermals. When it's windy and gusty, there is also turbulence and more speed is required. Everyone knows this, but we forget that we are flying light aircraft that loses speed quickly. This is why I carry more speed than necessary. It doesn't hurt if the runway is long enough. I need to bring in the Kolbra at 60mph, otherwise it won't have a enough flare with a passenger. During gusty conditions, I carry 65 or maybe a little more. By the way, my ASI reads ten mph higher. I bought it this way and have gotten use to reading it, so the ASI readings are 10mph higher than I quoted here. The Kolbra has VG's installed. 



Ralph

_________________
Ralph B

Kolb Kolbra 912uls
N20386
550 hours

h20maule(at)hotmail.com
Guest

Posted: Fri Sep 17, 2010 7:02 am Post subject: kolb stall

The main thing is not to get distracted when airspeed is critical i.e climbout and landing. The Kolb firestar has a nast stall that will quickly turn into a spin. No matter what I fly, I carry way more airpeed that I need. Unfortunately, I had to experience my uncle's death when he stalled our 1st Kolb Firestar amphib on takeoff back in 2000. I only show these photos to myself and other pilot to remind us how fast our lives, and the lives of others can be taken and destroyed forever.

 	  Quote: 	
		   Subject: Kolb-List: Re: kolb stall

 From: ul15(at)juno.com

 Date: Fri, 17 Sep 2010 07:39:00 -0700

 To: kolb-list(at)matronics.com

 --> Kolb-List message posted by: "Ralph B" <ul15(at)juno.com>

 The simple way not to stall on landing is to carry airspeed. During calm conditions the plane can be on the edge of a stall and land ok, if there are no thermals. When it's windy and gusty, there is also turbulence and more speed is required. Everyone knows this, but we forget that we are flying light aircraft that loses speed quickly. This is why I carry more speed than necessary. It doesn't hurt if the runway is long enough. I need to bring in the Kolbra at 60mph, otherwise it won't have a enough flare with a passenger. During gusty conditions, I carry 65 or maybe a little more. By the way, my ASI reads ten mph higher. I bought it this way and have gotten use to reading it, so the ASI readings are 10mph higher than I quoted here. The Kolbra has VG's installed. 

 Ralph

 --------

 Ralph B

 Original Firestar 447

 N91493 E-AB

 1000 hours

 23 years flying it

 Kolbra 912UL

 N20386

 2 years flying it

 120 hrs

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=312743#312743

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Jason Omelchuck

Joined: 07 May 2009
Posts: 120
Location: Portland Oregon

Posted: Fri Sep 17, 2010 8:32 am Post subject: Re: kolb stall

I love the way MY MKIII flies although I must admit that I was disappointed in how it flew when I first flew it.  I got my license in a 1946 J3 cub and the Kolb flies very differently.  Now that I have about 100 hours in the Kolb, I think it is a great airplane, it just flies differently than the cub.



Looking back at the accidents that happen in Kolbs, it seems like they are mostly the classic stall spin in.  As many of you have stated, (with all airplanes) you must keep your speed above stall.  The thing that I noticed is different about very light HIGH DRAG airplanes (like Kolbs) is the rate at which they slow down.  Most of the airplanes (including the cub) that people train in do not slow down as fast.  I have noticed myself inadvertently at stall speed when messing around at altitude in my Kolb.  In the high drag airframe, when you pull the power the time to the airplane stalling is greatly reduced and the nose down required to prevent stall is much more pronounced than most training/lower drag airframes.  I believe that that shortened time and the view when the nose is low enough to prevent stall can catch pilots new to this kind of airplane by surprise.



One other thing I noticed about myself which may hold true with other people.  It is counter intuitive and extremely difficult to convince your brain to put the nose of the aircraft down when close to the ground.  Some of you have watched my videos of the simulated power outs I have done with the 180 turn back to the runway.  One thing I noticed after doing a bunch of them is I could feel a pre-stall buffet in some of the turns and it took some effort to convince my brain that putting the nose down is what I needed to do.  My tendency was to try and keep my path to the goal at the end of the runway which would have resulted in a stall.  When at altitude putting the nose down seems easy and it is what we are trained to do.  When we are at less than 500' the sight picture and instincts may drive us to react differently and this is area that most of us do not get training in so it is a new situation when it happens.  I recently read an article about a 300 hour helicopter pilot who was doing some night training and  the instructor pulled power at low level over a pitch black terrain.  The pilot said he hesitated to put the collective down because he had no idea what was beneath him.  This instinct to avoid the ground is very strong and to push the nose down towards it at low level takes some training and in a high drag airframe the time to over come that instinct is reduced because of the rate at which it slows down.



Like others have said here.  A low time Kolb pilot should use lots of power at all times.  



Best Wishes

Jason

Dana

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

Posted: Fri Sep 17, 2010 8:54 am Post subject: kolb stall

At 10:56 AM 9/17/2010, daniel myers wrote:

  	  Quote: 	
		  The main thing is not to get distracted when airspeed is critical i.e climbout and landing. The Kolb firestar has a nast stall that will quickly turn into a spin... 	


 My buddy's Firestar (the only Kolb I've flown other than my UltraStar) doesn't have a nasty stall at all, and neither does my US.  I'd go far as to say that if you have a FS with a "nasty" stall, then something is wrong with the plane.



 -Dana

 

 --

  **FLASH** Eveready Bunny arrested, charged with battery.    [quote][b]

Ralph B

Joined: 14 Apr 2007
Posts: 367
Location: Mound Minnesota

Posted: Fri Sep 17, 2010 10:58 am Post subject: Re: kolb stall

That "nasty" Kolb stall is due to wing loading. My Firestar has a gentle stall with 148 sq feet of wing. Take that same wing and double the wing loading like the Kolbra, and it can be a killer if you're not careful. When I was transitioning to the Kolbra, I would ask Mark why it wanted to drop as we were landing. I told him that my Firestar didn't do that. He couldn't give me an answer because that was the only Kolb he has flown. To keep from dropping the wing, I stay well away from stall. It scares me to slow it up on landing, and for good reason. On the other hand, if I do a power on stall at altitude, it refuses to drop because of the VG's.



Ralph

_________________
Ralph B

Kolb Kolbra 912uls
N20386
550 hours

John Hauck

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

Posted: Fri Sep 17, 2010 11:31 am Post subject: kolb stall

Dana/Gang:

  

 I have been very fortunate to have built and flown  extensively three Kolb models.  None of them breaks at stall.  They go  into a mush/stall unless I intentionally bring the nose up to about 45 deg until  the air speed zeroes out, then push the stick forward.

  

 Takes a while to learn to fly a Kolb.  One of  the tricks a Kolb will pull on a low time Kolb pilot is the mush/stall.   When the pilot gets into it, the Kolb will remain level, will maintain full  aileron authority, giving the Kolb pilot the sensation that he is still flying  while descending more than 2,000 FPM.  Most of these are survivable, but  the nose will drop if the Kolb pilot attempts to bring the nose up in the  mush/stall.  Then the Kolb becomes a lawn dart.

  

 I have been experimenting and flying Kolbs since  1984, and have well over 5,000.0 flight hours in most all models of Kolbs.   Their flight characteristics from my experience is very similar since they all  use the same airfoil.  Weight and size makes a little difference, but thats  about it.

  

 As with any fixed wing, they have to fly faster  than stall speed to fly.  That is pretty basic airmanship that applies to  any fixed wing.

  

 john h

 mkIII - 3,000.0+ hours

 912ULS - 440.0+ hours

  

 PS:  We just got back from making our  pilgrimage to John Williamson's Rock at Skinner Ranch, OR.

 [quote]    My buddy's Firestar (the only Kolb I've    flown other than my UltraStar) doesn't have a nasty stall at all, and neither    does my US.  I'd go far as to say that if you have a FS with a "nasty"    stall, then something is wrong with the plane.



-Dana

 

[b]

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

John Hauck

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

Posted: Fri Sep 17, 2010 11:37 am Post subject: kolb stall

> That "nasty" Kolb stall is due to wing loading.

 	  Quote: 	
		  

 Ralph


	


Ralph B/Gang:



I have yet to experience "That "nasty" Kolb stall" in any Kolb I have flown. 

In fact, I have never found anything "nasty" about the Kolb handling.  Just 

the opposite.  The most docile fixed wing I have ever flown.



john h

mkIII

Rock House, OR

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

h20maule(at)hotmail.com
Guest

Posted: Fri Sep 17, 2010 11:54 am Post subject: kolb stall

John, you have more hours in a kolb than anyone else on this list and probably in the world. But, I can name 4 guys that I know that have been killed from a takeoff stall in a firestar...all 4 experienced a wing drop or spin...perhaps nasty isnt the right word, but when family dies, it sucks...maybe I'm biased... Dont misunderstand me, I love the kolb, especially the firestar. I continue to fly my friends ml3xtra weekly and hope to build another firestar soon. 

Thanks

Daniel

Sent from my iPhone

On Sep 17, 2010, at 3:32 PM, "John Hauck" <jhauck(at)elmore.rr.com> wrote:

 	  Quote: 	

 > That "nasty" Kolb stall is due to wing loading.

> 

> Ralph

 Ralph B/Gang:

 I have yet to experience "That "nasty" Kolb stall" in any Kolb I have flown. In fact, I have never found anything "nasty" about the Kolb handling.  Just the opposite.  The most docile fixed wing I have ever flown.

 john h

 mkIII

 Rock House, OR

John Hauck

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

Posted: Fri Sep 17, 2010 12:40 pm Post subject: kolb stall

> John, you have more hours in a kolb than anyone else on this list and 

probably in the world. But, I can name 4 guys that I know that have been 

killed from a takeoff stall in a firestar...all 4 experienced a wing drop or 

spin...perhaps nasty isnt the right word, but when family dies, it 

sucks...maybe I'm biased... Dont misunderstand me, I love the kolb, 

especially the firestar. I continue to fly my friends ml3xtra weekly and 

hope to build another firestar soon.

 	  Quote: 	
		   Thanks

 Daniel


	


Daniel M/Gang:



Sorry to hear that.



I know nothing of the results of the investigations, but a Kolb in a nose 

high attitude that runs out of airspeed will drop the nose and normally a 

wing.  I think I mentioned that in a previous email, but not in the take off 

mode.  I also did not mention dropping a wing which they will do in that 

attitude.  Normally a take off stall is below normal straight and level 

stall speed because of lift from the prop.  One really has to get in an 

unusual attitude to get into this stall situation.  Most Kolbs will continue 

to climb at full throttle with the stick full aft, right back to the stop.



Any time someone stalls a Kolb it is because they let the Kolb get below the 

stall speed for that situation.  I get a lot us use out of my airspeed 

indicator.  I constantly cross check my ASI, especially when near the ground 

and especially when landing.



I also make it a habit to know what my stall speed is in different 

configurations, especially when flying with a passenger, or when loaded max 

gross for a cross country flight.



I am not good enough to know what my airspeed is without my ASI.



john h

mkIII

Rock House, OR

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

John Hauck

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

Posted: Fri Sep 17, 2010 1:04 pm Post subject: kolb stall

But, I can name 4 guys that I know that have been

 	  Quote: 	
		   killed from a takeoff stall in a firestar...all 4 experienced a wing drop 

 or spin...perhaps nasty isnt the right word, but when family dies, it 

 sucks...maybe I'm biased...

> Thanks

> Daniel


	




Daniel M/Gang:



If the pilot gets into a departure stall in a Kolb, holds the stick back 

(which is a normal reaction for most pilots), its going to drop the nose, a 

wing, and sping in a near vertical attitude (nose down).



You can experiment this at a safe altitude.



Close to the ground it is extremely difficult to push the stick forward and 

the nose down.



I had an engine failure with my mkIII powered with a 582 in Sep 1993.  It 

resulted in a departure stall at about 30 feet in a confined area.  I had 

half flaps (20 deg) in a level attitude, got behind the aircraft and mushed 

in flat.  Wiped the Hauck Main Gear off the fuselage, got some serious 

bruises, but no injuries.  A really dumb mistake on my part.  I hope I 

learned from that one.  The half flaps helped keep the aircraft level 

despite me trying to make the aircraft fly below stall speed.  I could not 

make it fly.  



john h

mkIII

Rock House, OR

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

Ralph B

Joined: 14 Apr 2007
Posts: 367
Location: Mound Minnesota

Posted: Fri Sep 17, 2010 1:13 pm Post subject: Re: kolb stall

John and others, maybe there is another factor happening with the "nasty" stall (Kolb drop). The Kolbra doesn't have a gap seal like other Kolbs. The wing center is filled in with the cockpit enclosure. It doesn't fill it in completely and there are air leaks around it. This may have something to do with the stall characteristics as a rectangular wing will stall first in the center at the gap seal. Has anyone ever flown a Kolb without the gap seal? If so, maybe try a stall and see what it does. This combined with more weight may have the type of effect that some pilots are seeing.



Ralph

_________________
Ralph B

Kolb Kolbra 912uls
N20386
550 hours

elleryweld(at)aol.com
Guest

Posted: Fri Sep 17, 2010 4:41 pm Post subject: kolb stall

I have flown my old firestar without the gap seal many times and even played with stalls in that configuration I really didnt notice any difference with or without the gap section 

 

     I have not flown the Mk3 without the center section but if I think of it I will try it sometime  to see if it makes any difference flying in it 

 

 

 Ellery Batchelder Jr.

   --

neilsenrm(at)gmail.com
Guest

Posted: Sat Sep 18, 2010 6:05 am Post subject: kolb stall

Hey All

  

 There has been a lot of good discussion since Scott's tragic accident. My concern is that it leaves the impression that there is a problem or bad flight characteristic with our airplanes which there is not.

   

 I'm not a major high time pilot but I have had the opportunity to fly quite a few different airplanes and none are as good as our Kolbs. Our planes have tremendous short field capabilities that when fully utilized (flaps and no power landings) does require a high level of precision. Pilots new to the Kolb flight characteristics will have problems with these flight characteristics no matter how skilled they are in other aircraft. Land with power and stay away from the flaps till you get very good at it. Then very gradually land with less power OR using more flaps. Don't progress too quickly. I have a set of fully retracted Kolb landing gear legs that I bent when I progressed to full flaps and no power way too quickly.   

 

 Flight instructors not used to our Kolbs don't train us how to handle our Kolbs properly/safely. I recently got my check ride with a GA instructor in my Kolb. I was praised for how well I flew the plane in everything but how I flew very short final. He felt I rounded out way too low and with too much airspeed. I think this is a very common mistake that most non Kolb instructors will make. Let me also explain I did fly a bit faster approach rounded out lower because my instructor was a good 100 lbs heaver than anyone I had ever flown in my plane and I was using a very long 2500 ft grass strip. Yes we were a bit over gross weight.

   

 Rick Neilsen

 1st Redrive VW Powered MKIIIC



  [quote][b]

Dana

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

Posted: Sat Sep 18, 2010 6:16 am Post subject: kolb stall

--------------------------------------------------

"John Hauck" <jhauck(at)elmore.rr.com> wrote:

(09/17/2010 16:35)



 	  Quote: 	
		   I know nothing of the results of the investigations, but a Kolb in a nose 

 high attitude that runs out of airspeed will drop the nose and normally a 

 wing....


	


Especially if it's a new airplane that might not be properly trimmed 

out yet.



-Dana

jbhart(at)onlyinternet.ne
Guest

Posted: Sun Sep 19, 2010 7:28 am Post subject: kolb stall

Kolbers,



A couple of comments.  VG's will move the center of lift a little to the 

rear.  Also different planes of the same model will stall differently due to 

differences in cg.  Moving them to the rear will give a more gentle break 

and/or mush.  Move them forward, and the stall will be more pronounced.



Jack B. Hart FF004

Winchester, IN

gtaylor35918(at)roadrunne
Guest

Posted: Sun Sep 19, 2010 2:51 pm Post subject: kolb stall

Not to ask a stupid question, I am familiar with CG, is VG a typo, or 

something else.

Thanks, Greg

---

williamtsullivan(at)att.n
Guest

Posted: Sun Sep 19, 2010 3:03 pm Post subject: Kolb stall

  VG's are vortex generators.  Look them up on the Matronics Wiki for discussions.  Jack Hart has an excellent web site, and they can also be looked up there.  Look it up on the web as "Firefly Slide Show".  I don't have the address handy.  

 

                                             Bill Sullivan

                                             Windsor Locks, Ct

jbhart(at)onlyinternet.ne
Guest

Posted: Sun Sep 19, 2010 3:09 pm Post subject: kolb stall

At 06:37 PM 9/19/10 -0400, you wrote:

 	  Quote: 	
		  



Not to ask a stupid question, I am familiar with CG, is VG a typo, or 

something else.

---------------------------
	




Greg,



VG's is a short form for vortex generators



Jack B. Hart FF004

Winchester, IN

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