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Mk III max takeoff weight

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John Hauck

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

Posted: Sun Jan 08, 2012 10:50 am Post subject: Mk III max takeoff weight

John H., I've read your stories of taking potential customers, but were

those flights with a 582 or a 912?

Folks, feel free to email me off list if you don't want to post to the

forum.



Rick Girard

 



Rick G/Kolbers:



I have flown passengers with the 582, 912 80 and 100 horse engines in the

MKIIIc.  No problem with the 582 and heavy loads.  Been to long to remember

numbers.  Factory MKIIIc's didn't have rate of climb instruments.



Flew my MKIIIc with 582, placarded for 1,200 lbs, regularly at 1,100 to

1,200 lbs with no problems.  Performed quite well.



john h

mkIII

Titus, Alabama

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

John Hauck

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

Posted: Sun Jan 08, 2012 1:51 pm Post subject: Mk III max takeoff weight

What's max continuous rpm on a 582?

 

Way back when my MKIII was 582 powered max continuous cruise was 6,500, and I usually cruised at 5,800.  Aircraft was propped to turn 6,500 rpm straight and level WOT.

 

A couple hundred rpm increase makes a lot of difference in climb performance.

 

Holding the stick in your gut sounds to me like you are still dealing with a high thrust line.  A high thrust line will rob you of much hp and performance.  Sounds like very poor performance for any model Kolb.

 

Got a good half hour flight time between and around the rain showers today.  Did a high overhead circling approach from 2,000 feet to the sod strip at Wetumpka Airport.  That is fun to do in any airplane, especially a Kolb.

 

john h

mkIII

Titus, Alabama

 

 

  200/250 ft by the time I reached the road at the end with the stick in my lap 

 



Rick

[quote]  [b]

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

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sun Jan 08, 2012 5:16 pm Post subject: Mk III max takeoff weight

John, I use 6300 as max, although I got the prop a little flat once and saw 6860 before I dialed it back. That, too was a long flat climb. :-{ I need to put Ken's prop on the airplane after I shorten each blade 1 1/2". It's a 70 right now and if I allow for just 1/2" clearance to the boom it's will run a 67.

 I'm also going to revisit the carb synch. This is a relatively new engine (40 hours as of yesterday eve) and the cables may have stretched. I just want to know it's making every last bit of power she can.

 Thrust line is now dead stock. When I moved the engine back 3/4" to allow the starter on the "E" drive to clear the rear spar, I was able to bring the engine down. No more spacers, and the last time I changed it I flipped the Lord mounts back over to short side up, too. I gave up the fight and finally killed the lawn dart syndrome with 7" long trim tabs on the inboard end of each elevator. Now the trim system is adjustable depending on throttle setting and bank angle. Friday I was doing linked 45 degree banked turns. I had to high side the ailerons a bit, but once everything is set the IIIX tracks right around. A little rudder to help the ailerons when reversing the turn and she swings right out of one turn and into the other. Hit my turbulence every time. I learned something else in all the testing. Sealing the gap between horizontal stab and the boom tube and the stab and the elevator results in much improved elevator AND rudder response. Even at 1100 lb. I can pull the stick all the way back until it hits the seat rail and keep it there in a falling leaf stall. A light touch on the rudder will raise a wing. Yesterday I descended 1000' that way in less than a minute. The vario said I was doing 1200 fpm down, which tallies with the altimeter. All the while the nose stayed pointed into the wind.

 Also, the demonstrated crosswind capability of the Mk IIIX is 13 mph with the wind at 90 to the runway. Did that yesterday morning 5 times in a row.

In short, I'm really learning to love the IIIX. My perfect Mk III Kolb would be a IIIX with a bobbed nose and not quite such a flat bottom. About 1/2 way between a C and X would be perfect, IMHO. That and a one piece, forward tilting canopy with gas cylinders. I'm just too stiff to squeeze through either of the III's doors anymore.

 Even just the way it is, she's a sweet little plane.

Rick



On Sun, Jan 8, 2012 at 3:49 PM, John Hauck <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

  	  Quote: 	
		  

What's max continuous rpm on a 582? 

 

Way back when my MKIII was 582 powered max continuous cruise was 6,500, and I usually cruised at 5,800.  Aircraft was propped to turn 6,500 rpm straight and level WOT. 

 

A couple hundred rpm increase makes a lot of difference in climb performance. 

 

Holding the stick in your gut sounds to me like you are still dealing with a high thrust line.  A high thrust line will rob you of much hp and performance.  Sounds like very poor performance for any model Kolb. 

 

Got a good half hour flight time between and around the rain showers today.  Did a high overhead circling approach from 2,000 feet to the sod strip at Wetumpka Airport.  That is fun to do in any airplane, especially a Kolb. 

 

john h 

mkIII

Titus, Alabama 

 

  



  200/250 ft by the time I reached the road at the end with the stick in my lap  

 



Rick 

 	  Quote: 	
		     	
 

   	  Quote: 	
		  



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-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx



 



  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

zeprep251(at)aol.com
Guest

Posted: Mon Jan 09, 2012 5:54 am Post subject: Mk III max takeoff weight

John,

Your reply struck a cord with me.Loaded,my MK3 climbs better at 2900rpm(jabiru direct drive) than it does at WOT 3150.The amount of stick back pressure drops off as well.My heaviest lift off in 75 degrees was 1205#(at)1100 ' msl

John Hauck

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

Posted: Mon Jan 09, 2012 6:59 am Post subject: Mk III max takeoff weight

Your reply struck a cord with me.Loaded,my MK3 climbs better at

2900rpm(jabiru direct drive) than it does at WOT 3150.The amount of stick

back pressure drops off as well.My heaviest lift off in 75 degrees was

1205#(at)1100 ' msl.

G.Aman MK3c Jabiru 2200a 670 hrs. 



Gary A/Kolbers:



Takes HP to keep that high thrust line from pushing us into the ground.

After many hours flying my MKIII with 80 HP, I was alarmed on my first

takeoff with the 100 horse.  The MKIII didn't want to break ground.  I

backed off the power and she came right up.  Didn't take long to readjust to

the bigger engine, and I never had that problem again.



I believe that not only do we have the high thrust line working against us,

but we also have a less than efficient engine mount configuration.  The more

power we have, the more the engine is pushed out of alignment with the

airframe.  Softer Lord Mounts aggravate this condition.  I remember flying

my FS with softer Lord Mounts.  On one occasion, at wide open throttle, the

FS would not accelerate past 65 or 70 mph.  Thought I had an engine problem.

I slowly started backed off the throttle.  As I did, the airspeed started to

increase.  I very slowly increased throttle and airspeed also increased.  I

think the engine power was overpowering the soft Lord Mounts to the point of

kicking the thrust line so far out of alignment it would not fly any faster.

Now I insure I have the hardest Lord Mounts on my MKIII to prevent this from

happening.



I have landed and taken off from 9,927 feet ASL at Leadville, CO, at max

gross weight.  Although the pilot was behind the power curve, the MKIII did

a good job.  There is a big transition for a sea level pilot put into a

10,000 foot environment.



Most of my flying out West is around 5,000 feet up to 14,500 feet.  The

912ULS and the MKIII perform well.  Flying out there every day, one soon

adjusts to high altitude flying.



Also, local flying is done primarily with an empty airplane.  When I load up

to take a long cross country it takes a day or two to become adjusted to

flying a heavy airplane again.  Then that becomes normal.



john h

mkIII

Titus, Alabama - Watching the rain drops fall on a warm, wet, and foggy

Monday morning.

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

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Mon Jan 09, 2012 5:00 pm Post subject: Mk III max takeoff weight

So I cut down Ken's 70 inch prop to 67" and there's a knuckles clearance to the boom. Before that I spent a good part of the morning cleaning and balancing it. Put the WD prop protractor on my prop and measured it before taking it off, then set the new prop the same. Wouldn't get over 5850 in climb or 6100 flat out. Cylinder head temp on #2 set off the alarm so I had to keep the engine at 5600 rpm in cruise to keep the CHT at 268 and keep that annoying red light from flashing. That stuff they teach you about loading up the engine is true. Got back to the house and started re-pitching the prop when friend, EAA Chapter 88 president, and Airbike Ace Paul Fiebich landed and taxied up. Finished up torquing the prop bolts as he was getting ready to leave so I followed him out. Now I get 6250 in climb and 6450 flat out. CHT's are down, EGT's are acceptable and I got 200 more fpm for my effort. Now she climbs at 800 fpm. No free lunch, she's a 68 mph IAS airplane now at 5800 rpm. But, she's a ball to fly now. I wish she were mine, I know there's 100 lbs. that could come off her and that would work the same wonders for her that taking 70 lbs. did for mine.

For those of you out there building, resist the temptation to add, add, add. As Burt used to tell the LongEZ builders, if you want to add something to the airplane throw it up in the air. If it comes back down, it's too heavy. Make 550 lb. the maximum weight you will tolerate. My Mk III at 535 lbs. is a kick to fly. At 610 it was a slug no better than a Cessna 150. When I rebuild her I am going to get her to 500 lbs. like Homer intended.

 We have had the most beautiful January I've ever seen here in Kansas and I've gotten this Mk IIIX to fly pretty good for a fat girl. :-}

Rick Girard



On Mon, Jan 9, 2012 at 8:56 AM, John Hauck <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: "John Hauck" <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)>

  

 

 

  Your reply struck a cord with me.Loaded,my MK3 climbs better at

 2900rpm(jabiru direct drive) than it does at WOT 3150.The amount of stick

 back pressure drops off as well.My heaviest lift off in 75 degrees was

 1205#(at)1100 ' msl.

 G.Aman MK3c Jabiru 2200a 670 hrs.

 

 

 

 Gary A/Kolbers:

 

 Takes HP to keep that high thrust line from pushing us into the ground.

 After many hours flying my MKIII with 80 HP, I was alarmed on my first

 takeoff with the 100 horse.  The MKIII didn't want to break ground.  I

 backed off the power and she came right up.  Didn't take long to readjust to

 the bigger engine, and I never had that problem again.

 

 I believe that not only do we have the high thrust line working against us,

 but we also have a less than efficient engine mount configuration.  The more

 power we have, the more the engine is pushed out of alignment with the

 airframe.  Softer Lord Mounts aggravate this condition.  I remember flying

 my FS with softer Lord Mounts.  On one occasion, at wide open throttle, the

 FS would not accelerate past 65 or 70 mph.  Thought I had an engine problem.

 I slowly started backed off the throttle.  As I did, the airspeed started to

 increase.  I very slowly increased throttle and airspeed also increased.  I

 think the engine power was overpowering the soft Lord Mounts to the point of

 kicking the thrust line so far out of alignment it would not fly any faster.

 Now I insure I have the hardest Lord Mounts on my MKIII to prevent this from

 happening.

 

 I have landed and taken off from 9,927 feet ASL at Leadville, CO, at max

 gross weight.  Although the pilot was behind the power curve, the MKIII did

 a good job.  There is a big transition for a sea level pilot put into a

 10,000 foot environment.

 

 Most of my flying out West is around 5,000 feet up to 14,500 feet.  The

 912ULS and the MKIII perform well.  Flying out there every day, one soon

 adjusts to high altitude flying.

 

 Also, local flying is done primarily with an empty airplane.  When I load up

 to take a long cross country it takes a day or two to become adjusted to

 flying a heavy airplane again.  Then that becomes normal.

 

 john h

 mkIII

 Titus, Alabama - Watching the rain drops fall on a warm, wet, and foggy

 Monday morning.

 

 

 

 

 

 

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

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-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx



 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

Watkinsdw

Joined: 15 Mar 2009
Posts: 138
Location: Deerfield Beach, FL

Posted: Fri Jan 13, 2012 12:30 pm Post subject: Re: Mk III max takeoff weight

OK, this something I've been wondering about.

My Mk IIIC has gross weight listed in the log book and the ID plate as 1050.

Eventually, I'd like to add an amphib system. Empty weight is 590 lbs., and a Full Lotus system plus 10 to 15 gallons of fuel starts to add up fast.

I weigh in at about 195. I think the 912S will handle a bit more, but wonder how to avoid making a really expensive single place Kolb.

(My wife would kinda like to come along...)

How do I increase the official GW? Any other suggestions on this fantasy?

Dave

neilsenrm(at)gmail.com
Guest

Posted: Fri Jan 13, 2012 9:00 pm Post subject: Mk III max takeoff weight

Dave 



You have done well to keep the empty weight down to 590. I understand you want to increase the gross weight. Engine power isn't the limiting factor and the FAA isn't either. The important part is the air frame. The factory publishes the gross weight as 1000lbs. They do allow some margin extra and I for one have increased my MKIIIC to1050lbs. I also make a point of flying only in smooth air when near the 1050lbs. limit. At least one of our group has registered and flown at 1200lbs but he did beef up the wings to be able to safely do this. Does your plane have all those modifications? That pilot is also the test pilot on that plane every time he flies at those weights. Do you KNOW what is the limit is in your plane? Do you want to test this with your wife on board? Do you have a ballistic chute? What is the cost of a air frame failure? 

 



Food for thought.

Rick Neilsen

Redrive VW Powered MKIIIC



On Fri, Jan 13, 2012 at 5:18 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:

 [quote]Dave, I actually asked this very question of my local FAA guy at the FSDO. The answer is pretty simple, you redo all your testing at the new gross weight, make a logbook entry to that effect and you're done. 



 Rick Girard



On Fri, Jan 13, 2012 at 2:30 PM, Watkinsdw <david.watkins0(at)gmail.com (david.watkins0(at)gmail.com)> wrote:

 

 	  Quote: 	
		   --> Kolb-List message posted by: "Watkinsdw" <david.watkins0(at)gmail.com (david.watkins0(at)gmail.com)>

 

 OK, this something I've been wondering about.

 My Mk IIIC has gross weight listed in the log book and the ID plate as 1050.

 Eventually, I'd like to add an amphib system. Empty weight is 590 lbs., and a Full Lotus system plus 10 to 15 gallons of fuel starts to add up fast.

 I weigh in at about 195. I think the 912S will handle a bit more, but wonder how to avoid making a really expensive single place Kolb.

 (My wife would kinda like to come along...)

 How do I increase the official GW? Any other suggestions on this fantasy?

 Dave

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=363639#363639

 

 

 

 

 

 

 



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 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========

 

 

 

 	




-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

    - Groucho Marx



 

   	  Quote: 	
		  



get="_blank">http://www.matronics.com/Navigator?Kolb-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	




[b]

John Hauck

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

Posted: Fri Jan 13, 2012 9:44 pm Post subject: Mk III max takeoff weight

At least one of our group has registered and flown at 1200lbs but he did

beef up the wings to be able to safely do this. Does your plane have all

those modifications? That pilot is also the test pilot on that plane every

time he flies at those weights.  



Rick Neilsen

 



Rick N/Kolbers:



If that test pilot makes it until 15 March 2012, he will have flown more

than a quarter million miles and 3,100.0 plus hours during the past 20

years.  Almost 2,000.0 hours and 160,000 miles of that cross country, at or

close to max gross weight of 1,200 lbs.



He may be out of the test phase by now.



The old MKIII still has a ways to go to catch his 1992 Dodge/Cummins with

388,000 plus miles and 6,500.0+ hours in 20 years.



john h

mkIII

Titus, Alabama

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

pj.ladd(at)btinternet.com
Guest

Posted: Sat Jan 14, 2012 2:20 am Post subject: Mk III max takeoff weight

but wonder how to avoid making a really expensive single place  Kolb.

(My wife would kinda like to come along...)

  

 Looks as if you are planning a really expensive one  place, or maybe two place grave.

 You will need a lot of beefing up backed up by a  lot of knowledge. Never mind the legality think of airframe  stresses.

  

 Pat

 



   [quote][b]

Watkinsdw

Joined: 15 Mar 2009
Posts: 138
Location: Deerfield Beach, FL

Posted: Sat Jan 14, 2012 5:33 am Post subject: Re: Mk III max takeoff weight

Thanks, guys,

I'd be interested in knowing what airframe changes would make it safer.

I've see Mk III's at S&F with floats, and would like to be able to take advantage of all the lakes and rivers in S. FL.

Maybe Bryan is my best source for technical advice on this.

I do have a BRS and would like to keep the wife. We're going on 25 years, and I'm almost off probation!

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Sat Jan 14, 2012 5:52 am Post subject: Mk III max takeoff weight

Dave,



  I've passed the 40 year mark, and I'm pretty sure you never get off probation.



Mike Welch



 

On Jan 14, 2012, at 7:33 AM, Watkinsdw wrote:



 	  Quote: 	
		   

 

 Thanks, guys,

 I'd be interested in knowing what airframe changes would make it safer.

 I've see Mk III's at S&F with floats, and would like to be able to take advantage of all the lakes and rivers in S. FL.

 Maybe Bryan is my best source for technical advice on this.

 I do have a BRS and would like to keep the wife. We're going on 25 years, and I'm almost off probation!

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=363716#363716

John Hauck

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

Posted: Sat Jan 14, 2012 6:20 am Post subject: Mk III max takeoff weight

I'd be interested in knowing what airframe changes would make it safer.

 

David Watkins

David W/Kolbers:



I think Rick N was referring to me when he spoke of a test pilot and a 1200

lb max gross weight MKIII.



To answer your question, we didn't do anything to the airframe to beef it

up.  My MKIII airframe was built at the old Kolb Factory in January and

February 1991, by me and Brother Jim Hauck.  We did make some changes to the

airframe and other components, but not to increase max gross weight

capability.  Each was blessed each morning when Homer Kolb came to work.

Many of these changes were incorporated in the MKIII kits.  This was during

the time the first 12 MKIII airframes were being built and prior to shipment

of the first MKIII Kit, Number 1, to Rudy Doctor.  My airframe is Number 11.

Most of you MKIII builders and flyers don't know that a lot of the

components and changes to the original MKIII Kit were designed and

fabricated by my Brother Jim Hauck, with a little help from his little

Brother, me.



I did add additional lateral bracing to the wings, and reinforced the noses

of all 10 ribs and the tails of the first four outboard ribs on each wing

panel.  This was done in anticipation of winds and weather I would encounter

on my 1994 flight around CONUS and up to the North Slope of Alaska.  The

changes to the ribs were per a plans sheet by Dennis Souder to reinforce the

outboard wing rib of all kits to help prevent damage during wing folding and

handling.



Other mods, moving main gear forward, etc., had nothing to do with

increasing the gross weight capability of my MKIII.  The standard MKIII is

overbuilt (my opinion).



We did little things like increase bolt sizes from 5/16" to 3/8" for the

inboard main spar attachment to the fuselage.  Not much else.



I don't recommend anyone change the gross weight of the MKIII without

coordinating with Kolb Aircraft and other proper procedures with the FAA.



Again, my MKIII was built and changes blessed by Homer Kolb, placarded for

1,200 lbs max gross weight, which is indicated on my Airworthiness

Certificate.  It has been thoroughly tested and proved to be a tremendous

little airplane.  I had no idea Miss P'fer ("P" fer plane) would ever

accomplish the flights she has made the last 20 years.  She sits patiently

in the old sagging T hanger at Gantt International Airport, ready and

willing to go anywhere I am courageous enough to point her.



I think if you contact Bryan, he will tell you your MKIII will be able to

haul floats and a passenger.  It has been done in the past.



john h

mkIII

Titus, Alabama

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

Dana

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

Posted: Sat Jan 14, 2012 6:26 am Post subject: Mk III max takeoff weight

At 11:58 PM 1/13/2012, Rick Neilsen wrote:



  	  Quote: 	
		  You have done well to keep the empty weight down to 590. I understand you want to increase the gross weight. Engine power isn't the limiting factor and the FAA isn't either. The important part is the air frame. The factory publishes the gross weight as 1000lbs. They do allow some margin extra and I for one have increased my MKIIIC to1050lbs. I also make a point of flying only in smooth air when near the 1050lbs. limit... 	


 There's a simple relationship (at least in theory) between gross weight and load factor.  If, for example, the aircraft was designed to the utility category limit load factor of 4.4g positive, increasing the gross weight from 1000 to 1200 lbs reduced your load factor to 3.66, or a bit less than the normal category limit of 3.8.  Fly the airplane gently in smooth air and you'll have no problem... but you _are_ pushing the limit of parameters that were created for a reason.



 Many aircraft are certificated to normal category with full load and utility category with a reduced load.



 Now, I don't know what actual load factor the MKIII was designed to  (anybody?).  In reality, there will likely be one point of the structure that is the weakest link and other areas may well be stronger.  Beefing up that weak link may allow it to carry more load, until some other weak link fails.  To know for sure requires knowledge of the actual design numbers.  You might, for example, beef up the one critical point to be 20% stronger only to have something else fail at only 10% over the max.  Or the plane may already be overbuilt; planes often are, to take advantage of readily available materials instead of using the smallest possible size.  John's example shows that 1200# is possible for one particular well built and well maintained aircraft.



 Performance issues are another story.  Add weight and climb gets worse, stall speed and fuel consumption increase, etc.  A friend of mine put floats (of course there's a drag issue there too) on a 503 powered FSII, and what had been a plane with sparkling performance turned into one that flew, in his words, "like a cinder block".



 -Dana



 

 --

 A tree: first you chop it down, then you chop it up.

    [quote][b]

neilsenrm(at)gmail.com
Guest

Posted: Sat Jan 14, 2012 7:05 am Post subject: Mk III max takeoff weight

John I didn't mean to infer that your plane is unsafe but by definition you are still the test pilot. I felt very comfortable flying in it with you except for maybe one of those high banked turns around a monument at Monument Valley.

 



The point is our planes were design to fly with a maximum gross weight of 1000lbs with a safety margin. The designer tried to have a margin to allow for some poor workman ship, age, long term air frame stress, corrosion etc. I talked at length with Dennis Souder the structural engineer for the MKIIIC and he would not budge on the 1000lb. limit. He indicated there is more safety margin on the MKIII than any other Kolb but..... I have also read crash investigation reports where intended structural improvements actually weaken the air frame or moved the stress to a place that wasn't up to the task. John seems to have built his plane in a way the survives but? Some airplanes have hour limits before they need to be rebuilt, is that from structural failures of is it calculated?

 



Rick Neilsen

Redrive VW Powered MKIIIC

 

[quote] Rick N/Kolbers:

 

 If that test pilot makes it until 15 March 2012, he will have flown more

 than a quarter million miles and 3,100.0 plus hours during the past 20

 years.  Almost 2,000.0 hours and 160,000 miles of that cross country, at or

 close to max gross weight of 1,200 lbs.

 

 He may be out of the test phase by now.

 

 The old MKIII still has a ways to go to catch his 1992 Dodge/Cummins with

 388,000 plus miles and 6,500.0+ hours in 20 years.

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 

 

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 http://forums.matronics.com

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 le, List Admin.

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

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 [b]

herbgh(at)nctc.com
Guest

Posted: Sat Jan 14, 2012 7:05 am Post subject: Mk III max takeoff weight

Interesting stuff , John....



    My MkIII was built in Montana or the Dakotas,,there bouts, by a 

couple of fellows..  It had golf cart size tires and heavy steel gear 

legs...that were not very well tempered...  It weighted 490 some odd 

pounds...with a 532 and three blade IVO...  Herb

At 08:17 AM 1/14/2012, you wrote:

 	  Quote: 	
		  





I'd be interested in knowing what airframe changes would make it safer.



David Watkins

David W/Kolbers:



I think Rick N was referring to me when he spoke of a test pilot and a 1200

lb max gross weight MKIII.



To answer your question, we didn't do anything to the airframe to beef it

up.  My MKIII airframe was built at the old Kolb Factory in January and

February 1991, by me and Brother Jim Hauck.  We did make some changes to the

airframe and other components, but not to increase max gross weight

capability.  Each was blessed each morning when Homer Kolb came to work.

Many of these changes were incorporated in the MKIII kits.  This was during

the time the first 12 MKIII airframes were being built and prior to shipment

of the first MKIII Kit, Number 1, to Rudy Doctor.  My airframe is Number 11.

Most of you MKIII builders and flyers don't know that a lot of the

components and changes to the original MKIII Kit were designed and

fabricated by my Brother Jim Hauck, with a little help from his little

Brother, me.



I did add additional lateral bracing to the wings, and reinforced the noses

of all 10 ribs and the tails of the first four outboard ribs on each wing

panel.  This was done in anticipation of winds and weather I would encounter

on my 1994 flight around CONUS and up to the North Slope of Alaska.  The

changes to the ribs were per a plans sheet by Dennis Souder to reinforce the

outboard wing rib of all kits to help prevent damage during wing folding and

handling.



Other mods, moving main gear forward, etc., had nothing to do with

increasing the gross weight capability of my MKIII.  The standard MKIII is

overbuilt (my opinion).



We did little things like increase bolt sizes from 5/16" to 3/8" for the

inboard main spar attachment to the fuselage.  Not much else.



I don't recommend anyone change the gross weight of the MKIII without

coordinating with Kolb Aircraft and other proper procedures with the FAA.



Again, my MKIII was built and changes blessed by Homer Kolb, placarded for

1,200 lbs max gross weight, which is indicated on my Airworthiness

Certificate.  It has been thoroughly tested and proved to be a tremendous

little airplane.  I had no idea Miss P'fer ("P" fer plane) would ever

accomplish the flights she has made the last 20 years.  She sits patiently

in the old sagging T hanger at Gantt International Airport, ready and

willing to go anywhere I am courageous enough to point her.



I think if you contact Bryan, he will tell you your MKIII will be able to

haul floats and a passenger.  It has been done in the past.



john h

mkIII

Titus, Alabama

Dana

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

Posted: Sat Jan 14, 2012 7:37 am Post subject: Mk III max takeoff weight

At 10:02 AM 1/14/2012, Rick Neilsen wrote:

  	  Quote: 	
		  Some airplanes have hour limits before they need to be rebuilt, is that from structural failures of is it calculated? 	


 Metal fatigues, and the fatigue behavior is predictable.  This can be used to set life limits, for a specific number of load/unload cycles.  The numbers, of course, are adjusted if problems are found during inspections.  Light planes rarely reach the number of cycles that airliners do.  



 -Dana

 --

 To be sure of hitting the target, shoot first and call whatever you hit the target.

    [quote][b]

captainron1(at)cox.net
Guest

Posted: Sat Jan 14, 2012 10:11 am Post subject: Mk III max takeoff weight

It may have had more to do with the Rotax 65hp 582 than anything else.... ?

Ron Mason

KFHU

===================



---- Rick Neilsen <neilsenrm(at)gmail.com> wrote: 



=============

John I didn't mean to infer that your plane is unsafe but by definition you

are still the test pilot. I felt very comfortable flying in it with you

except for maybe one of those high banked turns around a monument

at Monument Valley.



The point is our planes were design to fly with a maximum gross weight of

1000lbs with a safety margin. The designer tried to have a margin to allow

for some poor workman ship, age, long term air frame stress, corrosion etc.

I talked at length with Dennis Souder the structural engineer for the

MKIIIC and he would not budge on the 1000lb. limit. He indicated there is

more safety margin on the MKIII than any other Kolb but..... I have also

read crash investigation reports where intended structural improvements

actually weaken the air frame or moved the stress to a place that wasn't up

to the task. John seems to have built his plane in a way the survives but?

Some airplanes have hour limits before they need to be rebuilt, is that

from structural failures of is it calculated?



Rick Neilsen

Redrive VW Powered MKIIIC



 	  Quote: 	
		   Rick N/Kolbers:



 If that test pilot makes it until 15 March 2012, he will have flown more

 than a quarter million miles and 3,100.0 plus hours during the past 20

 years.  Almost 2,000.0 hours and 160,000 miles of that cross country, at or

 close to max gross weight of 1,200 lbs.



 He may be out of the test phase by now.



 The old MKIII still has a ways to go to catch his 1992 Dodge/Cummins with

 388,000 plus miles and 6,500.0+ hours in 20 years.



 john h

 mkIII

 Titus, Alabama






	


--

kugelair.com

neilsenrm(at)gmail.com
Guest

Posted: Sun Jan 15, 2012 9:08 am Post subject: Mk III max takeoff weight

Rick



I'm real interested in how you figure that a VW on a Kolb is less safe below gross weight than going 20 percent over factory recommended maximum gross weight in a Rotax powered Kolb. Are you figuring this with all of John's modifications at 1200lbs. Are you aware that people put the 912 series of Rotax engines on Kolbs? The 912 engines weigh a bit more than the 110-140 lbs. you are talking about. Also my VW is a bit less than the 200+ you talk about. 

 



My KOLB MKIIIC has a empty weight of 598lbs fuel drained but otherwise wet and ready to fly. I was careful but my plane has two coats of silver UV paint , full rear enclosure with storage shelves and pockets behind the seats for camping gear, full factory upholstery with added sound insulation and solid steel landing gear. I never weighed my engine nor have I weighed a wet 912 engine but based on my aircraft empty I would figure the VW to be real close to the Rotax 912 fully configured and ready to fly. 

 



Rick Neilsen

Redrive VW Powered MKIIIC



On Sat, Jan 14, 2012 at 1:01 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:

 [quote]I've always found that the Kolb guys do the right thing in their designs, and if that is true in limit loads, too, then the designer would have used a safety factor of 1.5 (pretty much an aircraft industry standard) so the ultimate load would be 6 g's.  Limit loads are defined as loads that can be applied that result in no deformation of the structure. Even if the limit load is reduced to 3 and a fraction, unless you are going out and doing snap rolls at max gross your chances of hitting it are slim and nil.

  Then there is the fact that Va, maneuvering speed goes up with load, not down.

Rick, as far as safety goes, if the spar carry through is designed for 4g's with a 110 to 140 lb. engine, it's much less safe putting a 200 lb.+ VW with redrive on the aircraft than just increasing max gross to 1200 lb.

  I've tested the Mk IIIX to 1108lb, so far, and if the wind stays in the low teens this afternoon I'll have tested it to 1200 lb. by this evening. I worry a lot more about the degradation of climb rate at that weight than I do about limit load.

  



Rick Girard



[b]

neilsenrm(at)gmail.com
Guest

Posted: Mon Jan 16, 2012 8:32 am Post subject: Mk III max takeoff weight

OK 



Rick/All

I only hear about the 912 dry weight. You can't accurately compare engine weights dry verses ready to fly. So why do 912 powered Kolbs end up weighing about the same as my VW? I'm good but with all I have in my MKIIIC I can't believe by your figures that I have trimmed 60-80lbs off the average stock MKIIIC. My plane weighs 598lbs., the old high mount with the 5lb. engine adapter was 604lbs. That is two weighings years apart with two different sets of scales Could it be that VWs and Rotax engines are heavyer than Rotax is advertising?  I guess we need to watch the weights as more of the VW powered Kolbs are being built. 

 



VW engines aren't sold for our Kolbs as a package yet. Be careful what you put on them. If you don't they will get heavy. I don't recommend a magneto and certainly not two, they are heavy, expensive, under powered, and unreliable. I got about a pound off the diel accessory case by removing two unused mounting ears and drilling lightning holes(the bed mount we use doesn't stress this case like the difocal mount did). Also if I changed to the new 100cc bigger bore nickasil cylinders, that do a better job transferring heat, I would cut another 10lbs. And there is now a lighter starter than what I have, scratch another pound. 

 



My point is that a  well built redrive VW engine will end up weighing within single digits in US pounds of the 10-15 thousand dollar more expensive Rotax 912. If you fly over remote parts of Alaska buy the Rotax. If you don't and don't mind experimenting a bit try a VW. With every new VW built we get a better and more standardized engine. 

 



Rick Neilsen

1st Redrive VW Powered MKIIIC



On Sun, Jan 15, 2012 at 2:14 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:

  [quote]They're putting Rotax 912's on Kolb's? Really? Well, what will they think of next?All up installed weight of a 912 is right at 140 lb. dry. The 582 complete with Honda Sabre radiator is 115. I averaged the VW weight between Valley Engineering's weight of 185 and that reported by Wayne Clagg for his fat fin VW at 224 installed on his Zenith 701, also with a VE redrive.

   



Rick



On Sun, Jan 15, 2012 at 11:06 AM, Rick Neilsen <neilsenrm(at)gmail.com (neilsenrm(at)gmail.com)> wrote:

  



 	  Quote: 	
		   Rick



I'm real interested in how you figure that a VW on a Kolb is less safe below gross weight than going 20 percent over factory recommended maximum gross weight in a Rotax powered Kolb. Are you figuring this with all of John's modifications at 1200lbs. Are you aware that people put the 912 series of Rotax engines on Kolbs? The 912 engines weigh a bit more than the 110-140 lbs. you are talking about. Also my VW is a bit less than the 200+ you talk about. 

    



My KOLB MKIIIC has a empty weight of 598lbs fuel drained but otherwise wet and ready to fly. I was careful but my plane has two coats of silver UV paint , full rear enclosure with storage shelves and pockets behind the seats for camping gear, full factory upholstery with added sound insulation and solid steel landing gear. I never weighed my engine nor have I weighed a wet 912 engine but based on my aircraft empty I would figure the VW to be real close to the Rotax 912 fully configured and ready to fly. 

    



Rick Neilsen

Redrive VW Powered MKIIIC



On Sat, Jan 14, 2012 at 1:01 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:

     	  Quote: 	
		  I've always found that the Kolb guys do the right thing in their designs, and if that is true in limit loads, too, then the designer would have used a safety factor of 1.5 (pretty much an aircraft industry standard) so the ultimate load would be 6 g's.     Limit loads are defined as loads that can be applied that result in no deformation of the structure. Even if the limit load is reduced to 3 and a fraction, unless you are going out and doing snap rolls at max gross your chances of hitting it are slim and nil.

     Then there is the fact that Va, maneuvering speed goes up with load, not down.

Rick, as far as safety goes, if the spar carry through is designed for 4g's with a 110 to 140 lb. engine, it's much less safe putting a 200 lb.+ VW with redrive on the aircraft than just increasing max gross to 1200 lb.

     I've tested the Mk IIIX to 1108lb, so far, and if the wind stays in the low teens this afternoon I'll have tested it to 1200 lb. by this evening. I worry a lot more about the degradation of climb rate at that weight than I do about limit load.

     



Rick Girard







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-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

     - Groucho Marx



 



   	  Quote: 	
		  



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