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williamtsullivan(at)att.n
Guest

Posted: Fri Apr 18, 2008 12:04 pm Post subject: Homer Kolb

Curiosity question- I know Homer Kolb experimented with various designs. There was even a reference to a multi-engine design. Did he ever experiment with a bi-plane version? The only plane mentioned today that is a lot different than today's production versions is the Ultrastar. Apparently there are a lot of them still flying. When did the Ultrastar go out of production? Does anyone know if Homer still has some radically different version on paper, tucked in a drawer, that never even hit prototype? I can't see a man like him letting his ingenuity retire.

   

  do not archive

                                                            Bill Sullivan

                                                             FS/KX/447

                                                            Windsor Locks, Ct.

 [quote][b]

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Fri Apr 18, 2008 1:07 pm Post subject: Re: Homer Kolb

Dave put multi engines on a Kolb Firestar     Great idea, but there was interaction between the props that produced to much vibration.



Mike

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

Kolb MK-III Xtra, 912-S

Dana

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

Posted: Fri Apr 18, 2008 1:30 pm Post subject: Homer Kolb

At 04:02 PM 4/18/2008, william sullivan wrote:

 	  Quote: 	
		  Curiosity question- I know Homer Kolb experimented with various designs. 

There was even a reference to a multi-engine design. Did he ever 

experiment with a bi-plane version? The only plane mentioned today that is 

a lot different than today's production versions is the Ultrastar. 

Apparently there are a lot of them still flying. When did the Ultrastar go 

out of production? Does anyone know if Homer still has some radically 

different version on paper, tucked in a drawer, that never even hit 

prototype? I can't see a man like him letting his ingenuity retire.


	


Well, there was the Kolb Flyer (predecessor to the Ultrastar) which looked 

like an US with two 14HP Solo engines mounted on a short crossbar where the 

US engine is.  I think there were a few even simpler aircraft 

earlier.  Later, there was the Kolb Laser, a conventional low wing tractor 

airplane of which only a couple of examples were ever built.  Never heard 

of a Kolb biplane.



-Dana

--

  Blow your mind, smoke gunpowder.

mdnanwelch7(at)hotmail.co
Guest

Posted: Fri Apr 18, 2008 2:13 pm Post subject: Homer Kolb

Curiosity question- I know Homer Kolb experimented with various designs. There was even a reference to a multi-engine design. 



do not archive



Bill Sullivan

Bill,



  Awesome as the idea may be, to have a new twin-engined Kolb (especially a twin-engined Xtra), if I'm not mistaken, this could NOT be flown under Sport Pilot Rules.



  You would need a regular pilot's license, with a multi-engine endorsement.



  I have the pilot's license.  Let's get TNK to work on the twin Xtra design, and I'll get a "multi" rating.



Just musing,



Mike Welch

(with only one engine) 

                                                         



_________________________________________________________________

Get in touch in an instant. Get Windows Live Messenger now.

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Dana

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

Posted: Fri Apr 18, 2008 2:53 pm Post subject: Homer Kolb

At 06:10 PM 4/18/2008, Mike Welch wrote:



 	  Quote: 	
		  Awesome as the idea may be, to have a new twin-engined Kolb (especially a 

twin-engined Xtra), if I'm not mistaken, this could NOT be flown under 

Sport Pilot Rules.



   You would need a regular pilot's license, with a multi-engine 

 endorsement...


	


The old twin engined Kolb Flyer was 103 legal, needing no license at all...



-Dana



--

  Hard work has a future payoff.  Laziness pays off now.

David Lucas

Joined: 10 Jan 2006
Posts: 79
Location: Europe. based Amsterdam NL

Posted: Sat Apr 19, 2008 12:47 pm Post subject: Re: Homer Kolb

If twin engines pose a classification problem, how  about a single engine driving two props ?



David.

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slyck(at)frontiernet.net
Guest

Posted: Sat Apr 19, 2008 2:02 pm Post subject: Homer Kolb

Interesting.  That would  take care of some harmonic issues and clear  

a more properly located

boom tube,  On the downside is added weight and maintenance.



BB,  suzi powered MkIII,  back at work on the most recent mod.  Too hot

outside but nice in the cave.

do not archive



On 19, Apr 2008, at 4:47 PM, David Lucas wrote:



 	  Quote: 	
		   



 If twin engines pose a classification problem, how  about a single  

 engine driving two props ?



 David.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=177875#177875





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 http://forums.matronics.com//files/april07_026a_165.jpg

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sat Apr 19, 2008 6:52 pm Post subject: Re: Homer Kolb

 	  David Lucas wrote: 	
		  If twin engines pose a classification problem, how  about a single engine driving two props ?



David. 	




There is always someone out there that will try something very stupid, and driving 2 props with a single engine is definitely one of them.   It just adds complication, and increases chances of failures, while offering no safety advantage.



The whole idea of twin engines is to be able to fly the plane if one engine quits, even if the second engine results in an extended glide, you have something...  With a single engine and two props, you have every disadvantage of complication, and asymmetrical thrust and with no advantage of two engines.



Mike

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

Kolb MK-III Xtra, 912-S

Dana

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

Posted: Sun Apr 20, 2008 5:18 am Post subject: Homer Kolb

At 10:52 PM 4/19/2008, JetPilot wrote:



 	  Quote: 	
		  There is always someone out there that will try something very stupid, and 

driving 2 props with a single engine is definitely one of them.   It just 

adds complication, and increases chances of failures, while offering no 

safety advantage...


	


It's not stupid at all.  Well, it would be if you were doing it for safety 

reasons but that's not the point.  You _don't_ do it for safety reasons; 

you do it due to space constraints, where you don't have room for a single 

propeller large enough to be efficient.  That's why the Wrights did it; 

with limited HP they turned two absurdly large slow turning props, which is 

what got them such good efficiency.  I can see it being a good idea on a 

plane like the UltraStar, where prop ground clearance limits the kinds of 

fields you can operate from.



Of course it would totally screw up the wing folding...



-Dana



--

  "Makers of oils will assure you their lubricants will last the life of 

the transmission. This may be true, but that life can be longer if you 

change the oil.

David Lucas

Joined: 10 Jan 2006
Posts: 79
Location: Europe. based Amsterdam NL

Posted: Sun Apr 20, 2008 5:27 am Post subject: Re: Homer Kolb

 	  Quote: 	
		  There is always someone out there that will try something very stupid 	




Well maybe Mike, but this is NOT one of them. It is neither 'stupid' nor 'very stupid' (Nb. Your adjectives seem always to be way too strong). What it is, is the result of entrepreneurial spirit and technical expertise complete with the funds to follow up on it.



This application was flown on a proof of concept aircraft, the German FK11 (see attached photo), and while it did not go into production, this was because of other commitments stifling the project and not because of failure of the concept. It worked ! The idea was to get the props working in the cleanest air possible in a pusher application rather than directly behind the fuselage/wing area with all the conflicting air-flows there that negatively affecting performance and increasing noise levels.



 	  Quote: 	
		  driving 2 props with a single engine is definitely one of them 	




Wrong, some applications require two props to absorb the power, eg; the Russian Tupolev Tu-95 'Bear' one of the fastest subsonic aircraft flying today. but on the application I showed, it was for efficiency reasons, not power absorption. The reason for this layout I described above. A good reason !



 	  Quote: 	
		  The whole idea of twin engines is to be able to fly the plane if one engine quits, even if the second engine results in an extended glide, you have something... 	




Granted, this is one of the benefits of twin engine flying, even if, as you say, the second, or remaining engine only "takes you to the scene of the accident"   



 	  Quote: 	
		  With a single engine and two props, you have every disadvantage of complication, and asymmetrical thrust and with no advantage of two engines. 	
 



Well, that assumes engine failure being the one and only problem. What if a drive belt fails, it's happened right ? In this case the other prop will still be receiving power giving you further options that a single prop plane would not have. That seems like an advantage to me. You might well have to improve rudder authority in such a case, eg. Larger vertical stab or (dare I say) VG's, but if that's so, I don't see it as a disadvantage.



As to application to a Kolb, it might be possible. Someone had gone to the trouble to install twin engines but had consequential problems. This just might work. Someones curiosity might be satisfied by trying it. Who knows, that's all I posted it for.



Safe flying



David.

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JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Apr 21, 2008 8:35 am Post subject: Re: Homer Kolb

That dual prop setup on a small gas engine is nothing short of stupid, overly complicated, prone to failure, and dangerous.   The setup pictured does NOT compare to a large turboprop or hugely powerful engine where counter - rotating propellers would be beneficial, not even in the same league.



A setup similar to this was used on the wright flyer, but we have learned a lot since then, I would question anyones intelligence that would suggest that something is a good idea just because the wrights used it, that just shows poor judgment.



The fact that the single engine into a dual prop setup in the picture has never been used in any significant numbers should clue you in to the fact that it is not practical or even a good idea.   Its not rocket science, there is no excuse for anyone involved in building and flying airplanes to not be able to figure this one out.



Mike

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

Kolb MK-III Xtra, 912-S

lcottrell

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

Posted: Mon Apr 21, 2008 9:17 am Post subject: Homer Kolb

---

_________________
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Dana

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

Posted: Mon Apr 21, 2008 9:18 am Post subject: Homer Kolb

At 12:35 PM 4/21/2008, JetPilot wrote:



 	  Quote: 	
		  That dual prop setup on a small gas engine is nothing short of stupid, 

overly complicated, prone to failure, and dangerous.   The setup pictured 

does NOT compare to a large turboprop or hugely powerful engine where 

counter - rotating propellers would be beneficial...


	


But those _weren't_ counterrotating as far as I can tell (though they were 

on the Wright Flyer).  Furthermore, except for having two props, belts, 

bearings, etc. (none of which are particularly prone to failure compared to 

the engine itself) it's no more complicated than a single propeller belt 

redrive.



 	  Quote: 	
		  A setup similar to this was used on the wright flyer, but we have learned 

a lot since then, I would question anyones intelligence that would suggest 

that something is a good idea just because the wrights used it, that just 

shows poor judgment.


	


I didn't hear anybody say it "was a good idea just _because_ the Wrights 

used it".  I simply pointed out one of the reasons why the Wrights used it 

(maximizing propeller disk area in the space available), which could still 

make sense today.



 	  Quote: 	
		  The fact that the single engine into a dual prop setup in the picture has 

never been used in any significant numbers should clue you in to the fact 

that it is not practical or even a good idea.


	


Now, that's just a dumb statement, which could be applied to ANY idea 

that's not yet widespread.  If we all believed that there would be no new 

ideas.  It may well be true (almost certainly IS true) that dual props from 

a single engine doesn't make sense most of the time, but that doesn't mean 

that it NEVER makes sense.



-Dana

--

  Never vote for a politician who has to borrow a gun to go duck hunting

R. Hankins

Joined: 18 Jan 2006
Posts: 185
Location: Grants Pass, Oregon

Posted: Mon Apr 21, 2008 9:46 am Post subject: Re: Homer Kolb

David Lucas,

Do you know the diameters of the two three bladed props used and the power of the engine in the picture you posted?  This would be more efficient if longer two bladed props were used to increase disk area.  To do that, this mount would have to place the props behind the ailerons on a Kolb.  

Also, it looks like the props are turning the same direction, but the belt tensioners are on the same side of the frame.  If this is so, one belt is being tensioned on the loaded side.  This is not generally a good idea.



As configured in the photo, I doubt that this set up would be any more efficient on a Kolb than one larger diameter prop.



Compare the disk area of a 66" prop (13,685 sq.in.) to that of two 50" props (15,707 sq.in. total) and you can see that not much is gained.  The added weight, increased complexity and decreased efficiency of two smaller props v.s. one large one will likely outweigh any improvements from better airflow or the slight increase in disk area.



In short, I think this is a bad idea for a Kolb and I haven't used the word stupid anywhere.  I do have to admit it looks very cool though.  



Engineering is a series of compromises and decisions to reach a desired goal.  This design looks like a reasonable solution on the aircraft it was designed for. It would not be a good solution for a Kolb.

_________________
Roger in Oregon
1992 KXP 503 - N1782C

John Hauck

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

Posted: Mon Apr 21, 2008 9:59 am Post subject: Homer Kolb

> In short, I think this is a bad idea and I haven't used the word stupid 

anywhere.  I do have to admit it looks very cool though.

 	  Quote: 	
		  

 --------

 Roger in Oregon


	




Hi Gang:



Brother Jim and I have had a lot of ideas over the years.  Many were never 

carried through based on lack of time and money.



One of Jim's better ideas was to build a pusher with twin tailbooms with 

enough space inbetween to swing a nice size prop.  This concept could be 

single of twin engine.  Would bring the thrust line down behind the center 

of mass where it belongs.



I have oftened wondered what a rocket ship a Kolb would be with a thrust 

line in the center of mass.  Closest Homer ever came was the US.  It 

performed more like a tractor than the high thrust line pusher that eats up 

a lot of the profits before they can be spent on thrust.



john h

mkIII

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

David Lucas

Joined: 10 Jan 2006
Posts: 79
Location: Europe. based Amsterdam NL

Posted: Mon Apr 21, 2008 10:37 am Post subject: Re: Homer Kolb

Roger.     No, sorry, I haven't the spec's on the prop size, you'll just have to make an educated guess based on other items in the photo that may be familiar. The engine, however, is the 80 HP 3 cylinder, turbocharged, injected, FADEC controlled, liquid cooled engine that was developed for the 'Smart Car' by Mercedes Benz. The engine is a great little unit, but Smart have recently swapped to a Japanese engine for overseas sales due to the strength of the Euro. Pity, it had great potential for aero conversions. It met or exceeded most Rotax 912 performance figures so I'm told, especially economy and with auto gas at around US$ 9.00 / gallon over here thats quite an important factor. Yes US$ 9.00 per Gallon !



Mike,   A lot of earlier, not so successful, ideas are having a second life due to advances in technology. The Kevlar beams holding the prop mounts being an excellent example. Years ago the only option would have been something like a steel/metal frame which would have been too heavy. 



Jules Verne (Feb 8, 1828 – Mar 24, 1905) wrote about space, air, and underwater travel before navigable aircraft and practical submarines were invented, and before any means of space travel had been devised. Now a significant number of his ideas are just 'status quo'. All it took was increased technology. Got to keep an open mind about these things and be willing to have a second look instead of just slamming the door shut.



David.

airspeedx3(at)yahoo.com
Guest

Posted: Mon Apr 21, 2008 11:01 am Post subject: Homer Kolb

Mike Bigelow is frequently short of tackfulness.  So, in order to help tell his story, GEICO has asked me to help .......

   

  JetPilot <orcabonita(at)hotmail.com> wrote--> Kolb-List message posted by: "JetPilot" 



That dual prop setup on a small gas engine is nothing short of stupid, overly complicated, prone to failure, and dangerous. The setup pictured does NOT compare to a large turboprop or hugely powerful engine where counter - rotating propellers would be beneficial, not even in the same league.

   

  Dual propellers seem like a good idea at first, but their true value hasn't yet been discovered.  That's a nice shirt you are wearing.



A setup similar to this was used on the wright flyer, but we have  learned a lot since then, I would question anyones intelligence that would suggest that something is a good idea just because the wrights used it, that just shows poor judgment.

   

  History has progressed since the earlier examples of this idea.  A wise aviator would want to adhere to sound engineering principles, and approach this method prudently.



The fact that the single engine into a dual prop setup in the picture has never been used in any significant numbers should clue you in to the fact that it is not practical or even a good idea. Its not rocket science, there is no excuse for anyone involved in building and flying airplanes to not be able to figure this one out.

   

  [b]Although excellent working examples of this design may be rare, one wouldn want to be cautious before further recommending using this        Be a better friend, newshound, and   [quote][b]

John Hauck

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

Posted: Mon Apr 21, 2008 3:24 pm Post subject: Homer Kolb

The man that started it all, Homer Kolb.



Homer had just landed his 1985 Kolb Firestar, the 1985 Oshkosh Grand 

Champion Ultralight.



This aircraft was destroyed by Dick Rahill at Oshkosh in 1989.  Dick stalled 

in a tight turn to final about 25 feet AGL.



john h

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

John Hauck

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

Posted: Mon Apr 21, 2008 3:32 pm Post subject: Homer Kolb

> Homer had just landed his 1985 Kolb Firestar, the 1985 Oshkosh Grand

 	  Quote: 	
		   Champion Ultralight.


	




Forgot to mention, this photo was taken the day before the Kolb Father's Day 

Flyin last year.



Well..............I ain't perfect!



john h

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

rowedenny

Joined: 09 Mar 2008
Posts: 338
Location: Western PA

Posted: Mon Apr 21, 2008 5:50 pm Post subject: Homer Kolb

 	  Quote: 	
		  

 Hi Gang:




	


 	  Quote: 	
		   One of Jim's better ideas was to build a pusher with twin tailbooms with 

 enough space inbetween to swing a nice size prop.  This concept could be 

 single of twin engine.  Would bring the thrust line down behind the center 

 of mass where it belongs.




	


 	  Quote: 	
		   > john h

 mkIII



John,
	


Ever here of a plane called the Sadler Vampire?

Denny Rowe

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