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In-flight fuel mixture

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John Hauck

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

Posted: Sun Dec 11, 2011 10:28 am Post subject: In-flight fuel mixture

I am a great believer in reed valve engines with ceramic coated aluminum

cylinders.  They will take much more abuse than the steel liners with

aluminum pistons. 



Jack B. Hart FF004

 

Jack H/Kolbers:



Hope the new engines work out ok.  Rotax could use a little competition.



Reed valves were very popular back in the 60's and 70's on two stroke dirt

bikes.  Made those little two strokes scream, until they swallowed a reed.

I believe it was Polson that came up with a non-metallic reed valve to

preclude destroying an engine when a reed valve broke and went through it.



I am not familiar with "ceramic coated aluminum cylinders".  The 912's use a

metallic coated cylinder that comes out of the factory with .000" to .001"

cylinder wall to piston clearance.  That's tight.



Was interested in your statement above, "They will take much more abuse than

the steel liners with aluminum pistons."  Is the ceramic coating more

durable than nikasil and other metallic cylinder wall coatings?



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 Dec 11, 2011 10:58 am Post subject: In-flight fuel mixture

--

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

jbhart(at)onlyinternet.ne
Guest

Posted: Mon Dec 12, 2011 5:14 pm Post subject: In-flight fuel mixture

At 12:56 PM 12/11/11 -0600, you wrote:

[quote]

--

John Hauck

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

Posted: Mon Dec 12, 2011 6:18 pm Post subject: In-flight fuel mixture

Also one can run higher EGT with out fear of melting the pistons. 

 

With reduced piston to wall clearances, one can run simple very thin, light

and inexpensive piston rings.  



When I purchased the Victor 1+, which has a Nikasil coated cylinder, I asked

about TBO.  I was told to replace the piston rings after 600 hours, at 1,200

hours replace the piston and rings, at 1,800 hours replace the rings, and at

2,400 hours to replace the cylinder, piston and rings.  



Jack B. Hart FF004



Jack H/Kolbers:



Can you run higher EGT because the pistons are also coated?



The TBO figures are quite impressive.  Do you have knowledge of an owner

that has attained this much time on a Victor?



I wonder if those figures are for the user or lab environment?



john h

mkIII

Titus, Alabama

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

jbhart(at)onlyinternet.ne
Guest

Posted: Mon Dec 12, 2011 7:55 pm Post subject: In-flight fuel mixture

At 08:16 PM 12/12/11 -0600, you wrote:

 	  Quote: 	
		  



Jack H/Kolbers:
	


 	  Quote: 	
		  

Can you run higher EGT because the pistons are also coated?



The TBO figures are quite impressive.  Do you have knowledge of an owner

that has attained this much time on a Victor?



I wonder if those figures are for the user or lab environment?




	


John,



There are other ceramic coatings that are used as thermal barriers that can 

be applied to the top of the piston, the head inner surface and the exhaust 

ports.  When these have been applied, one can run higher EGT's.



I do not know of anyone who has run a Victor 1+ up to these hours. 600 hours 

for a ring replacement is not all that high when little four cycle diesel 

engines run several thousand hours with no ring replacement.  Also in 

searching the web I found:



http://www.ncccoat.com/PDF/NCCSAEtechnicalpaper.pdf



and:



http://www.mt-llc.com/tour/98winter_snowtech_article.pdf



The first is pretty technical.  The second describes repair.



I suspect these hours were found by running an engine for a given number of 

hours and then the engine was torn down and measurements were taken of the 

rings, piston, and cylinder.  And then from the wear found, extrapolations 

were made to come up for the TBO, ring, piston, and cylinder replacement.



Jack B. Hart FF004

Winchester, IN

John Hauck

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

Posted: Mon Dec 12, 2011 8:18 pm Post subject: In-flight fuel mixture

I do not know of anyone who has run a Victor 1+ up to these hours. 600 hours

for a ring replacement is not all that high when little four cycle diesel

engines run several thousand hours with no ring replacement 



Jack B. Hart FF004

 

Jack H/Kolbers:



Not really any comparison between longevity of a diesel four stroke and a

gasoline two stroke.



There is a facility in Auburn, Alabama, that recoats cylinders.  I rebuilt

my son's 450 Yamaha MX engine.  The cylinder was really buggered up.  They

did a good job, but it was expensive.



Good luck with the Victor.



john h

mkIII

Titus, Alabama

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

Thom Riddle

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

Posted: Tue Dec 13, 2011 7:44 am Post subject: Re: In-flight fuel mixture

Jack,

The second link you posted regarding repair, came up fine but when clicking on the first link all I go was several blank pages. They are both .pdf files so I know that is not the problem. I would very much like to read the first document. Any chance there might be another way to get to it?

_________________
Thom Riddle
Buffalo, NY (9G0)

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

jbhart(at)onlyinternet.ne
Guest

Posted: Tue Dec 13, 2011 5:35 pm Post subject: In-flight fuel mixture

At 07:44 AM 12/13/11 -0800, you wrote:

 	  Quote: 	
		  



Jack,

The second link you posted regarding repair, came up fine but when clicking 

on the first link all I go was several blank pages. They are both .pdf files 
	


so I know that is not the problem. I would very much like to read the first 

document. Any chance there might be another way to get to it?

 	  Quote: 	
		  


	


Thom,



I could not view it on my old computer as it will not accept the latest pdf 

viewing program upgrade.  On my new machine it came up just fine.  



I hope this helps.



Jack B. Hart FF004

Winchester, IN

do not archive

jbhart(at)onlyinternet.ne
Guest

Posted: Tue Dec 13, 2011 6:04 pm Post subject: In-flight fuel mixture

At 10:16 PM 12/12/11 -0600, you wrote:

 	  Quote: 	
		  



Jack H/Kolbers:



Not really any comparison between longevity of a diesel four stroke and a

gasoline two stroke.




	


John,



True, but the piston rings, the piston, and cylinder system is common to 

both two and four stroke engines.   The one difference is one power stroke 

per one revolution versus two revolutions.  With time, technology has 

marched forward and all engines are much more reliable.  I have an Impala 

with 240,000 miles and a Ford van with 330,000 miles.  No oil has to be 

added to either between oil changes.  I estimate the conservative running 

time (miles/60 mph) to be 4,000 hours on the Impala and 5,500 hours on the 

Ford.  



These figures lead me to believe that a 600 hour ring life time for the 

Victor 1+ may be conservative.  Also, I believe there are many Rotax two 

cycle engines flying that have long  passed the 300 hour TBO period.



All it takes to beat these TBO times is to use a good oil, and not too much 

of it, and keep the engine head and exhaust gas temperatures below the 

manufacturer's recommended maximums.   



Jack B. Hart FF004

Winchester, IN

John Hauck

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

Posted: Tue Dec 13, 2011 6:24 pm Post subject: In-flight fuel mixture

All it takes to beat these TBO times is to use a good oil, and not too much

of it, and keep the engine head and exhaust gas temperatures below the 

manufacturer's recommended maximums.   



Jack B. Hart FF004

 



I agree.



Also, Rotax TBO for other than certified engines, is recommended TBO.  Not

mandatory to tear down a good engine just because it has reached

"recommended TBO".

I pull with a 1992 Dodge/Cummins with approximately 6,500 hours on it.  That

is 388,000+ miles.  Engine is still as strong now as it was when new.



Sitting here patiently waiting for some of you Kolbers to get out there and

start putting some serious time on your engines, especially two strokes, no

matter what make or model.



The only way we are going to know if manufacturers of ultralight engines are

telling us the truth or blowing smoke is to get out there and fly.



john h

mkIII-3,100+ hours

912ULS-560.0+ hours

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

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