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Flight characteristics of the Kolb FSII & The Challenger
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WillUribe(at)aol.com
Guest

Posted: Fri Dec 07, 2007 7:55 pm Post subject: Flight characteristics of the Kolb FSII & The Challenger

Greetings, 

 The Challenger has been around forever, it is an old design. I have flown  my friend's Challenger and it flys OK. IMHO not as fun as my FireStar, but  when I flew the Challenger with the doors on, it scared the hell out  of me.  I just felt I didn't have the control authority I should have on  any airplane. I told my friend to remove the doors because if he ever lost the  rudder he would never be able to control it. 

 My friend has wiped out his noise gear twice and the main gear once.   I was with him in the back seat when we landed hard, the main gear cables broke  and one gear leg collapsed. That was the last time I flew in his Challenger.  Replacing the gear leg attachment is a major repair, you have to cut in half the  main aluminum tube that is part of the fuselage.  

 He really enjoys flying it, goes flying more then a couple of times a  week.  Other then the X-Air he learned to fly in the Challenger is the only  other airplane he has flown.  

 I like to fly low and slow and the FireStar will get me out of trouble in a  hurry when the wind changes.  The Challenger takes a little longer to react  to my inputs.

  

 Hope this helps.

 Will Uribe 

 FireStar II N4GU

 El Paso, TX but working in Philadelphia, PA

 do not archive





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  [quote][b]

pj.ladd(at)btinternet.com
Guest

Posted: Sat Dec 08, 2007 3:06 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

the main gear cables broke  and one gear leg  collapsed. >>

  

 Good grief Will, I would have bet you could lift  the Titanic with that braided cable. Even after the cable breaks there is   the torsion of the main fuselage longerons, which must be around 1,1/4"" in  diameter. I am surprised you didn`t break your back with an impact like that. If  he makes many similar  landings  and with a rcord of wiping off  nosewheels i don`t think I would want to fly with him at all.

 Friendship is  a wonderful thing.

  

 Cheers

  

 Pat

   [quote][b]

pj.ladd(at)btinternet.com
Guest

Posted: Sat Dec 08, 2007 3:31 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

only way once it progressed so far to get it back in line was cross control 

the critter>>



Hi Larry,

a lot of people seem to be running down the poor old Challenger so I assume 

therer must be something in it.. Perhaps it is something to do with the 

doors. As i selected the open cockpit version I never flew one with doors 

on.



I can only say that I almost always sideslipped in to a landing at my field, 

because I like doing it,  but as soon as  I let go of the fully crossed 

controls she would straighten up. That doesn`t sound to me like a plane 

without directional stability. Perhaps that dorsal fin addition to the tail 

fin really did work. I remember seeing about 5 Challengers waiting to take 

off from some  west coast airfield, Seattle or Vancouver, and I noticed that 

none of them had the dorsal fin. Perhaps it is unusual over there. With our 

system if a fault was discovered the PFA would prscribe a `fix" and ALL 

planes would have to be modified. Immediately if it was potentially 

dangerous fault, by the next C of A if it was considered minor.  In my case 

the dealer rang me, we fixed a date and he arrived and fitted the dorsal fin 

in my hangar within a few days. That does seem to indicate some urgency. 

Usually the pilot is left to make his own arrangements. Perhaps without the 

dorsal fin she really was as bad as you suggest.



The Challenger is not alone in needing a dorsal fin. I remember the B-17 had 

one added pretty quickly after the original design reached Squdrn service.



Cheers

Pat

pj.ladd(at)btinternet.com
Guest

Posted: Sat Dec 08, 2007 4:12 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

I understand it is not too difficult to accomplish the wiping off part since 

the nose gear is attached to an aluminum cross tube with two hose clamps.>>



Not exactly right John,

The nosewheel IS held on by two hose clamps but ham handedness is required 

to wipe it off.

I did put a couple extra jubilee clips on mine and the nose wheel was solid 

as a rock. Mind you I never wheelbarrowed the plane in on the nosewheel as 

is seen quite often  with tricycle undercart designs. That will collapse 

them no matter what sort of plane it is. I always operated from a farmers 

field which was not particlarly smooth and never had any trouble. The 

Challenger should have minimal weight on the nose, she sits on the tail 

wheel  when the pilot is not aboard, and the nosewheel is designed to keep 

the nose off the ground and to steer with. Thats all. If the pilot puts a 

load on any part of a plane which is outside the design parameters, it will 

break.



Regarding low time Kolb pilots giving advice on flying. I freely admit that 

I am in that category. It is also obvious that some pilots, particularly in 

the early days of ultralighting, taught themselves to fly. There was no 

other way. Some pilots got away with it but a lot were hurt and to recommend 

that course in these days when alternatives are available seems a bit 

perverse.

My comments were not based on my Kolb flying experience but on the 

accumulated experience of ALL pilots. Messing about just above the stall 

close to the ground is dangerous. Just as Neptune is always waiting for a 

sailor to make a mistake, Mr Newton is always there waiting for a pilot to 

mess up.It is simple enough, You get about 20 ft up in still air, 5 knots 

above the stall, a thermal goes up from a nearby field drawing air into 

itelf. Your still air changes to 5 knots on the tail, the plane stops 

flying, you have no height to get the nose down....Kaboong!



I have been there. When I was learning  hang gliding I tried to take off  as 

the wind dropped and broke my leg. Lucky to get away with it.



Pat

ElleryWeld(at)aol.com
Guest

Posted: Sat Dec 08, 2007 7:18 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

one more thing on a Challenger that I didn't care about  I had taken a passenger with me once in one and all he complained about was there is not enough room for his feet and he could not operate the rudder good enough from the back seat 

  

 one of the Challengers I know about  on his first few attempts of flying the rig had managed to break one of the main gear cables on a hard landing after a short flight a 100 feet or so down the strip and  it scared the $h!t out of him and he told me he didn't have any rudder control and there was something wrong with the plane  so I helped him fix it and he wasn't to crazy about trying it again,  so I tried it for him and it was like the other challengers I have flown, that's just the way they are.   that built confidence in him enough to try it on a later date and he has  had a few incidents with it  smashed  nose up a couple times 

  

 To keep this KOLB related I am still building  MK3xtra and Going to stick with KOLB Airplanes

  

 Ellery

 do not archive



hottest products and top money wasters of 2007.

  [quote][b]

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sat Dec 08, 2007 8:20 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

---

_________________
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Wade Lawicki

Joined: 27 May 2007
Posts: 31
Location: Nashville Tn.

Posted: Sat Dec 08, 2007 8:37 am Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

There is alot of talk about the challenger design  on other lists also.More of possible design flaws that have gone unchanged do to liability issues. They cant go back and say something was flawed without opening up litigation.  The main point being the leading edge attachment  using a RONY bracket that  was originally used on the single place and has not been changed since , and is also used on the 2 place models. Other issues are in a spar slice at the root section of the wing. here is a snip from the http://groups.yahoo.com/group/quicksilverultralightowners -



"I just left the drug store with the negatives of a 2 place challenger that came apart 4 years ago Killing both on board, I Represented USUA on the incident and partook in the investigation, I would show the video of the incident but the families don't deserve to re-live the trauma. I will post the investigative photos of the aftermath. Then you all can be the judge, Just know the flaw not only lies in the Ronny brackets/attach, it also exists in the Spar Splice at the root of the trailing edge which is in the wrong place to start and it is not a tight fit, its to short and to many rivets concentrated without any standard pattern, that matches AC-4313 for tube splices. In addition you have an airframe that is sold with no corrosion protection,stainless rivets,in an alclad frame with bare steel parts to boot, its a flying battery. I addressed my concerns and finding,reviewed a build manual only to be turned away by Dave Guliet.....What a pity because this could all be avoided. It will rear its ugly head as theses planes continue to age........Mark My words! "

 

Al Sibi

Director of Production Indus Aviation

Dallas Texas

Former Quick Dealer/ Region 4 USUA Regional Rep

Former Vice President Jersey Shore Ultralights 96-2000

I do not own or fly a challenger so, I make no claims myself but have heard this over and over on many lists but the challenger list and believe that anyone considering flying or buying one should be fully informed and cautious.



Fly Safe,   Wade

do not archive

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sat Dec 08, 2007 9:23 am Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

 	  pj.ladd(at)btinternet.com wrote: 	
		  

Hi ,

I would love to hear about them. I have flown a Challenger for years, built 

it myself and it always struck me as very strongly engineered. 



Pat 	




When making the decision of which plane to buy, I did a lot of research on accidents and failures.   In my research, one thing that turned up time and time again was structural failures of Challengers.   Documented cases, people talking about problems, it came up again and again.  Structural failures was reason enough to keep me away from this plane, but that combined with the rudder, and other things make it one of the very worst designs out there.  I suggest doing google searches of things like Challenger structural failure, problems, etc. etc.  Use lots of words and also use the advanced search to exclude the word shuttle...  It takes a while, but if you use imagination and take the time, you can find lots of good information.



It is very common for a person that has a plane to like it, and gain a false sense of security in it even if it is a bad, dangerous design.  I would suggest that you do research on the web, the information is there, lots of cases and discussion, if you really want to know the truth about Challengers.



I also did the same type of research on Kolb aircraft, and found very few cases of structural failures.   The things that caused the failures in the Kolbs are mostly older and have been fixed.  More ribs in wings, better welding...  What I never saw with Kolbs were lots unexplained failures and people talking about lots of structural problems in relation to Kolbs.  Made for an easy choice  



Mike

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

Kolb MK-III Xtra, 912-S

Jim ODay

Joined: 09 Jul 2007
Posts: 61
Location: Fargo North Dakota

Posted: Sat Dec 08, 2007 2:58 pm Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

The name of the plane says it all.



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_________________
Jim O'Day
Fargo, ND
Former Firestar II Builder/Pilot

azfirestar

Joined: 08 Dec 2007
Posts: 25

Posted: Sat Dec 08, 2007 8:03 pm Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

I found the postings on the rudder effectiveness of the Challenger very interesting.  The stability of a flying object about any axis is derived from the center of gravity (CG) being in front of the center of pressure (i.e. aerodynamic surface area).  I almost became an aviation statistic about 10 years ago as a passenger in a friend's Challenger II (the only time I ever wanted to jump out of a plane).  The CG was aft because of me (170 lb) in the back seat and the heavier 582 engine, and the center of pressure was forward because of the surface area of the doors.  The net result was the aircraft was not yaw-stable when the engine was throttled back and propwash reduced over the rudder.  The rudder was almost totally ineffective on final approach and we came very close to spinning in during multiple attempts to land.  If you have a Challenger II with a lighter engine, no doors, and/or flying solo, then you may not experience any problems.  



If the manufacturer has not done anything about the yaw stability, then I consider that disreputable.  Unfortunately, as someone said before, the legal repercussions of admitting the mistake are probably a big factor.



In regard to your first flight in a any aircraft, I don't recommend the crow hops down the runway if you are a low time pilot.  If you are a good pilot it may not be an issue, but the quick transitions from take off to landing could easily get a low time pilot into an awkward situation.  I have read multiple accident reports where someone was taxi testing an aircraft, got airborne unexpectedly and stalled due to some combination of unusual attitude, low airspeed, and insufficient throttle.

_________________
Dan G.
503 Firestar II
Tucson AZ

pj.ladd(at)btinternet.com
Guest

Posted: Sun Dec 09, 2007 2:07 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

f you have a Challenger II with a lighter engine, no doors, and/or flying 

solo, then you may not experience any problems.>>



Hi Dan,

thats interesting. I had a 503, no doors and usually flew solo. When I took 

a passenger I usually contrived that it was a slim female so you could well 

be right about the  C of G.



I think the C of G limits for the Xtra are specified as further forward here 

than in the USA also.



Cheers



Pat

pj.ladd(at)btinternet.com
Guest

Posted: Sun Dec 09, 2007 4:51 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

More of possible design flaws that have gone unchanged do to liability 

issues. They cant go back and say something was flawed without opening up 

litigation.>>



Hi Wade,

I dont think that there has been a history of problems with the Challenger 

over here.  Of course there are not that many flying here  compared to the 

numbers sold in the States.

I find it difficult to think that there are basic flaws in the design. With 

our system it would never have been licensed to fly here at all if the PFA 

Engineering dept considered it dangerous.  Granted that the design was 

introduced before we started using the tighter `Section S` standard but even 

then designs were scrutinised pretty carefully and many planes which had 

sold in their hundreds in other countries with no problems were not cleared 

for sale here.



We dont have the same propensity over here to sue over every error imagined 

or real ( but we are getting there) so I cannot believe that would prevent 

an upgrade of the design taking place.



Thanks for your input. Very nice to hear from someone with real experience 

who is not just passing on the rumours and half truths that exist.



Cheers



Pat

pj.ladd(at)btinternet.com
Guest

Posted: Sun Dec 09, 2007 4:53 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

They have some good features no doubt,  just not enough to prefer one over 

a Kolb.>>



Hi Larry,

well,  I have  a Kolb now so I guess that must make a statement.



Cheers



Pat

pj.ladd(at)btinternet.com
Guest

Posted: Sun Dec 09, 2007 5:02 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

passenger with me once in one and all he complained  about was there is not enough room for his feet>>

  

 Hi Ellery,

  

 Things were definitely awkward from the back seat  unless you had fairly long legs as there was nowhere to put your feet ecept in  the pedals. In my wifes case this meant that she had to slide right forward and  then she could hardly see out.

  

 I only flew a pilot in the back seat once and he  seemed to have no problems in control. My usual wandering up and down fifty feet  and 10 degree wanderings off course suddenly damped out and the plane ran is if  on rails. He was  an R A F pilot with the Red Arrows ( like the Blue Angels  but better Heh! Heh!)  so that probably explained it.

  

 Cheers

  

 Pat

   [quote][b]

Wade Lawicki

Joined: 27 May 2007
Posts: 31
Location: Nashville Tn.

Posted: Sun Dec 09, 2007 8:51 am Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

Pat,

       They now offer what is called a "High G kit" that patches some of the problem but, they don't say it is to fix a "PROBLEM". I have also seen some very large finlets for the tail that are advertised to help the rudder problem but i don't think they are sold by the factory, just someone who came up with a solution.  IMHO with the challenger design there are too many "ducks" out of the row for me to want to own, fly or be a passenger in one.



                          Fly Safe,

                                             Wade

do not archive

pj.ladd(at)btinternet.com
Guest

Posted: Tue Dec 11, 2007 4:43 am Post subject: Flight characteristics of the Kolb FSII & The Challenger

IMHO with the challenger design there are too many "ducks" out of the row 

for me to want to own, fly or be a passenger in one.>>



Hi  Wade,



I think the whole question is pretty much decided over here now.



I bought one of the very first Challenger kits sold here. Since then there 

have been several changes of dealership and I see that the franchise is up 

for sale again in the last few weeks.

The design, like that of the Kolb, has been overtaken by the newer planes 

now available and hardly any are now being sold.



Please everyone, don`t jump on me over my comments. I bought a Kolb because 

I have always liked the look of them and fell in love when I saw a picture 

tacked to a wall in a clubroom in my early flying days. But that was over 25 

years agoand they haven`t changed.. If I had not let my heart rule my head I 

would not have bought a Kolb but would have settled for a secondhand machine 

with a newer, cleaner  design. There are several available these days, with 

better cruise speed, burning around 12 litres per hour, with doors that fit, 

without a cranky flap system that digs in the back of your elbow, and a wing 

fold system which beats the Kolb system hands down. The tendency seems to be 

to put bigger and bigger engines and props on the Kolbs to coax a few more 

mph out of it when what is needed is a redesign.

But, most of the newer machines  are getting onto the `light aircraft` 

bracket and  I guess that I am an `ultralighter` at heart, and still hanker 

after the low and slow and ( cheap?) philosophy which started the whole 

ultralight thing so, come the Spring I shall be happy admiring the view 

through that fabulous nose as I trundle around at 65 mph , refueling every 

90 minutes or so but still happy and proud to be a Kolber when pilots walk 

up to this strange anachronism at a fly in and say `What is it?"



Incidentally I put up an ultralight flight at an `Auction of Promises` for 

the local church. It was sold for $200 to a guy who has never flown in a 

small aircraft and I know that he will enjoy a flight with me in the Kolb 

much more that he would being whipped off in an Ikarus at 120 mph.



Cheers



Pat

George Alexander

Joined: 10 Jan 2006
Posts: 245
Location: SW Florida

Posted: Tue Dec 11, 2007 5:55 am Post subject: Re: Flight characteristics of the Kolb FSII & The Challe

Pat:



Well said!  



 	  pj.ladd(at)btinternet.com wrote: 	
		  



<<<<SNIP>>>>



But, most of the newer machines are getting onto the `light aircraft` 

bracket and I guess that I am an `ultralighter` at heart, and still hanker 

after the low and slow and ( cheap?) philosophy which started the whole 

ultralight thing so, come the Spring I shall be happy admiring the view 

through that fabulous nose as I trundle around at 65 mph , refueling every 

90 minutes or so but still happy and proud to be a Kolber when pilots 

walk up to this strange anachronism at a fly in and say `What is it?"



<<<<SNIP>>>>



Cheers

Pat

_________________
George Alexander
FS II R503
E-LSA N709FS
http://www.oh2fly.net

Dennis.Kirby(at)kirtland.
Guest

Posted: Mon Dec 17, 2007 1:12 pm Post subject: Flight characteristics of the Kolb FSII & The Challenger

Not trying to beat this dead horse any more than necessary (and with no

offense to our fellow former-Challenger-owning Kolbers), but here's what

I've seen, from my limited experience with Challengers:



My flying buddy at my home airport owns a Challenger II (long wing) with

a 503.  You've heard me mention this guy - when we go flying together, I

always let him depart first, because he has a dismal climb rate compared

to my 912 Mark-III.  I catch up to him in short order.  But after we

form up and are in cruise, he can easily outrun my draggy Kolb.



This Challenger's empty weight is nearly 800 pounds (!!), so he has VERY

little excess power - especially at our field elevation of 6500 feet

MSL.  This, coupled with the fact that Challengers are known for their

lack of rudder authority, was the setup for disaster this past

September.



He took off on a warm, thermally afternoon to practice some touch and

go's.  Lots of dust devils in the area.  On his third circuit, after

takeoff, he was about 100 feet high and climbing (barely) when his

Challenger experienced an un-commanded yaw to the right.  Instinctively,

he put in left rudder, but with no effect.  Even with full left rudder

(and still at full power), the plane's nose was still swinging to the

right.  Meanwhile, with airflow no longer blowing over his wings from

directly head on, he began losing lift and was losing altitude quickly

while in a flat attitude.



He ended up pancaking it into the ground while still at full power.

Destroyed the aircraft.  My friend was lucky to escape this incident

with only bangs & bruises and a sprained ankle.  The most likely cause

of this accident was that he encountered a horizontal wind shear (like a

large dust devil, but without the dust) due to the unstable air near the

surface that day.  This Challenger did not have sufficient rudder

authority to overcome the horizontal wind gradient, nor did it have

sufficient power to penetrate or outclimb it.



While this set of weather conditions could happen to any of us, I like

to think that a Kolb would likely fare better if thrown in the same

situation.  I have the confidence that, with our better climb rates (if

not overloaded), and better directional stability, our Kolbs could more

easily overcome this kind of horizontal shear gradient.



Happy I chose a Kolb -



Dennis Kirby

Mark-III, 912, N93DK in

Cedar Crest, NM

Do not archive

indyaviator(at)gmail.com
Guest

Posted: Mon Dec 17, 2007 3:26 pm Post subject: Flight characteristics of the Kolb FSII & The Challenger

 	  Quote: 	
		  This Challenger's empty weight is nearly 800 pounds (!!),


	


Surely this cannot be right.  Empty weight of a Challenger is usually less than 400lbs.  Dioes he have a Chevy bigblock for and engine??



Bryan Dever 

  [quote][b]

John Hauck

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

Posted: Mon Dec 17, 2007 3:32 pm Post subject: Flight characteristics of the Kolb FSII & The Challenger

Bet you could get all that info and even more over at the  Challenger List.

  

 Challenger wannabie!

 [quote]    Surely this cannot be right.  Empty    weight of a Challenger is usually less than 400lbs.  Dioes he have a    Chevy bigblock for and engine??



Bryan Dever 

 

[b]

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

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