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stuart(at)harnerfarm.net
Guest

Posted: Fri Apr 24, 2015 9:58 am Post subject: Firefly/447 RPM question

Guys,

 

Here is a question for those that have a Firefly with a Rotax 447.

 

Assuming a properly dialed in propeller with a static full throttle output of 6300 RPM, what do you usually see at straight and level cruise RPM and speed?

 

For that matter, if you have any information of what airspeeds to expect at different throttle settings (straight and level) I would appreciate knowing what others are seeing.

 

I have been up a for a couple of short flights this spring and it seems to me that a comfortable airspeed is between 55 and 60 indicated, but that seems to be in the 4800 RPM range which is still giving me high EGT’s. I moved the needle clip down (more rich) one notch and that helped a lot. Now when I get a warning at mid-range, I just add a little “choke” to take care of it. I expect this problem to go away with warmer temps, but may have to fuss with the pitch a little.

 

I need MUCH more time in the air to sort this stuff all out, but the weather has not been cooperating very well. 

 

Any numbers you can give me for comparison/starting points would be appreciated.

 

Thanks,

 

Stuart

  [quote][b]

olendorf

Joined: 06 Jul 2006
Posts: 140
Location: Schenectady, NY USA

Posted: Fri Apr 24, 2015 11:42 am Post subject: Re: Firefly/447 RPM question

It all depends on what size prop you have.  And the drag of your craft.

I find 4800rpms to be just about the hot spot for my EGTs also.  4600-4800.  I try to stay out of that range.  I usually cruise around about 5500-5800rpm which provides 53-58mph airspeed.

_________________
Scott Olendorf
Original Firestar, Rotax 447, Powerfin prop
Schenectady, NY
http://sites.google.com/site/kolbfirestar/

Herbgh(at)nctc.com
Guest

Posted: Fri Apr 24, 2015 2:18 pm Post subject: Firefly/447 RPM question

Remember also...Stuart,,,that engine is not broken in...rings will seat 

in the 40+ hour range..temps usually drop...cht and egt...



    I cruised in the 5600 range and saw high 50's to low 60's using a 

three blade IVO..Herb



On 04/24/2015 02:42 PM, olendorf wrote:

 	  Quote: 	
		   



 It all depends on what size prop you have.  And the drag of your craft.

 I find 4800rpms to be just about the hot spot for my EGTs also.  4600-4800.  I try to stay out of that range.  I usually cruise around about 5500-5800rpm which provides 53-58mph airspeed.



 --------

 Scott Olendorf

 Original Firestar, Rotax 447, Powerfin prop

 Schenectady, NY

 http://sites.google.com/site/kolbfirestar/





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=441248#441248

stuart(at)harnerfarm.net
Guest

Posted: Fri Apr 24, 2015 2:38 pm Post subject: Firefly/447 RPM question

Thanks Scott. I have a 3 blade 60" Warp Drive at 7.5° of pitch. The amount

of drag is a little harder to figure. I have the short windshield, double

struts, and the larger wheels with brakes.



Less pitch will give more RPM but less thrust so that may be the way to go.

There is no shortage of thrust, that's for sure!



I need to go back and review to see if less pitch increases EGT or if I need

a little more. 



I have had it up to 70 IAS in a descent and that seemed "uncomfortable" to

me.  Maybe I am just not used to it yet, but I really like the way it

"feels" between 55 and 60.



Someone else said "climb at 50, cruise at 50 and approach at 50" or

something like that.  So far that seems to fit.  I didn't build it to travel

with anyway.



Your Firestar is slightly larger than the Firefly but if you have a full

enclosure it may have about the same amount of drag as I do.



Thanks again,



Stuart



--

stuart(at)harnerfarm.net
Guest

Posted: Fri Apr 24, 2015 4:22 pm Post subject: Firefly/447 RPM question

Thanks Herb,



Sounds like a mandate to go fly! Tiny Tack is currently showing 19, halfway

there.



The darned wind comes up with the sun and temps these days.  I am sure after

some time aloft, I will be able to handle more adverse conditions but at

this stage of the game I don't need any more to deal with, so will wait.



When you are a little kid at heart, waiting is sooooo HARD to do!



Patience was my dad's virtue, not mine.  GRRRR!



I sure like the power (thrust) I am getting with the 447. Sometimes I wonder

if it is overkill for the Firefly.  Better to have it and not need it than

need it and not have it.  (True of most things in life)



Thanks again,



Stuart



--

Herbgh(at)nctc.com
Guest

Posted: Fri Apr 24, 2015 4:43 pm Post subject: Firefly/447 RPM question

I bought the low time Firefly in Conn...pictures only...one of those 

impulse things....! January...no way to get it....then had buyers 

remorse...not because of the nice looking plane or nice trailer...just 

taking my ole bones on a 2000 mile round trip....so I sold...it....  



   Hope to get back in the air before too long...Firestar this time 

maybe.?  More local too!   447 engine...not the 503 I hope...or a 

Firestar with no engine...for I have another 447...older model... single 

seater..project would be good...damaged cage ok..if not too bad...



   Herb



On 04/24/2015 07:22 PM, Stuart Harner wrote:

[quote] 



 Thanks Herb,



 Sounds like a mandate to go fly! Tiny Tack is currently showing 19, halfway

 there.



 The darned wind comes up with the sun and temps these days.  I am sure after

 some time aloft, I will be able to handle more adverse conditions but at

 this stage of the game I don't need any more to deal with, so will wait.



 When you are a little kid at heart, waiting is sooooo HARD to do!



 Patience was my dad's virtue, not mine.  GRRRR!



 I sure like the power (thrust) I am getting with the 447. Sometimes I wonder

 if it is overkill for the Firefly.  Better to have it and not need it than

 need it and not have it.  (True of most things in life)



 Thanks again,



 Stuart



 --

russk50(at)gmail.com
Guest

Posted: Fri Apr 24, 2015 5:13 pm Post subject: Firefly/447 RPM question

Herb

Dunno if this is of any help to you but I have an open trailer, set up for a Kolb, that you can borrow anytime you need it — but it’s in  MAINE!

Prolly 5-6 hrs north of CT. But you’re welcome to use it

Fair winds,

Russ K

[quote] On Apr 24, 2015, at 8:43 PM, Herb <Herbgh(at)nctc.com> wrote:

 I bought the low time Firefly in Conn...pictures only...one of those impulse things....! January...no way to get it....then had buyers remorse...not because of the nice looking plane or nice trailer...just taking my ole bones on a 2000 mile round trip....so I sold...it....  

  Hope to get back in the air before too long...Firestar this time maybe.?  More local too!   447 engine...not the 503 I hope...or a Firestar with no engine...for I have another 447...older model... single seater..project would be good...damaged cage ok..if not too bad...

  Herb

 On 04/24/2015 07:22 PM, Stuart Harner wrote:

> 

> 

> Thanks Herb,

> 

> Sounds like a mandate to go fly! Tiny Tack is currently showing 19, halfway

> there.

> 

> The darned wind comes up with the sun and temps these days.  I am sure after

> some time aloft, I will be able to handle more adverse conditions but at

> this stage of the game I don't need any more to deal with, so will wait.

> 

> When you are a little kid at heart, waiting is sooooo HARD to do!

> 

> Patience was my dad's virtue, not mine.  GRRRR!

> 

> I sure like the power (thrust) I am getting with the 447. Sometimes I wonder

> if it is overkill for the Firefly.  Better to have it and not need it than

> need it and not have it.  (True of most things in life)

> 

> Thanks again,

> 

> Stuart

> 

> --

Herbgh(at)nctc.com
Guest

Posted: Fri Apr 24, 2015 6:19 pm Post subject: Firefly/447 RPM question

Maine?  Isn't that near Greenland??     Thanks for the offer...One 

more plane and I am out of the business for a while...Herb



On 04/24/2015 08:13 PM, kinne russ wrote:

[quote] 



 Herb

 Dunno if this is of any help to you but I have an open trailer, set up for a Kolb, that you can borrow anytime you need it — but it’s in  MAINE!

 Prolly 5-6 hrs north of CT. But you’re welcome to use it

 Fair winds,

 Russ K

> On Apr 24, 2015, at 8:43 PM, Herb <Herbgh(at)nctc.com> wrote:

>

> 

>

> I bought the low time Firefly in Conn...pictures only...one of those impulse things....! January...no way to get it....then had buyers remorse...not because of the nice looking plane or nice trailer...just taking my ole bones on a 2000 mile round trip....so I sold...it....  

>

>   Hope to get back in the air before too long...Firestar this time maybe.?  More local too!   447 engine...not the 503 I hope...or a Firestar with no engine...for I have another 447...older model... single seater..project would be good...damaged cage ok..if not too bad...

>

>   Herb

>

> On 04/24/2015 07:22 PM, Stuart Harner wrote:

>> 

>>

>> Thanks Herb,

>>

>> Sounds like a mandate to go fly! Tiny Tack is currently showing 19, halfway

>> there.

>>

>> The darned wind comes up with the sun and temps these days.  I am sure after

>> some time aloft, I will be able to handle more adverse conditions but at

>> this stage of the game I don't need any more to deal with, so will wait.

>>

>> When you are a little kid at heart, waiting is sooooo HARD to do!

>>

>> Patience was my dad's virtue, not mine.  GRRRR!

>>

>> I sure like the power (thrust) I am getting with the 447. Sometimes I wonder

>> if it is overkill for the Firefly.  Better to have it and not need it than

>> need it and not have it.  (True of most things in life)

>>

>> Thanks again,

>>

>> Stuart

>>

>> --

undoctor(at)rcn.com
Guest

Posted: Fri Apr 24, 2015 6:26 pm Post subject: Firefly/447 RPM question

Hi Stuart,

The 447 on my FireFly was set for 6200 RPMs sratic. At 4800 RPMs I felt like I was plowing through the air. Not wuite slow flying but close to it. When I cruised at 5200 my air speed was 65 - 70 mph and it felt good there. 

The air strip where I hangared my FF wasn't the easiest place to land. You had to clear power lines then drop down into a gully between trees and land uphill. I often ran final between 65 and 70 mph because handling and control was excellent at that speed. Just use caution dropping your flaperons over 65 mph. 

If it would do you any good I have some videos on youtube taken with a "hat cam" where you can see my asi and vsi. When I look at them I can feel the speed and control inputs. Maybe it wouldn't work for you but if you want to check them out go to   youtube.com/undoctor

Fair winds and blue skies. I sure do miss my beloved FF. 

Dave Kulp

Bethlehem, PA





Sent from my Verizon Wireless 4G LTE smartphone



-------- Original message --------

From: Stuart Harner  

Date:04/24/2015  6:38 PM  (GMT-05:00) 

To: kolb-list(at)matronics.com 

Subject: RE: Kolb-List: Re: Firefly/447 RPM question 

--> Kolb-List message posted by: "Stuart Harner" <stuart(at)harnerfarm.net>



Thanks Scott. I have a 3 blade 60" Warp Drive at 7.5Â° of pitch. The amount

of drag is a little harder to figure. I have the short windshield, double

struts, and the larger wheels with brakes.



Less pitch will give more RPM but less thrust so that may be the way to go.

There is no shortage of thrust, that's for sure!



I need to go back and review to see if less pitch increases EGT or if I need

a little more. 



I have had it up to 70 IAS in a descent and that seemed "uncomfortable" to

me.  Maybe I am just not used to it yet, but I really like the way it

"feels" between 55 and 60.



Someone else said "climb at 50, cruise at 50 and approach at 50" or

something like that.  So far that seems to fit.  I didn't build it to travel

with anyway.



Your Firestar is slightly larger than the Firefly but if you have a full

enclosure it may have about the same amount of drag as I do.



Thanks again,



Stuart



--

Airknocker

Joined: 26 Apr 2014
Posts: 6
Location: ND

Posted: Fri Apr 24, 2015 7:39 pm Post subject: Re: Firefly/447 RPM question

Hi Dave,



Thanks, I will check out your videos.



I have been considering getting a sports cam to record my flights so I can review them later. My hope is to be able to learn things that I was too busy to notice when in the air.



Did you find video useful in that way?



One of the many things I need to do is get some time aloft with my phone where I can see the GPS speedometer readout. by flying different routes and then again in reverse, I hope to get an idea at to the accuracy of the ASI.

_________________
"I don't care, I'm still free. You can't take the sky from me" - Josh Wedon

olendorf

Joined: 06 Jul 2006
Posts: 140
Location: Schenectady, NY USA

Posted: Sat Apr 25, 2015 3:56 am Post subject: Re: Firefly/447 RPM question

 	  stuart(at)harnerfarm.net wrote: 	
		  

...

Less pitch will give more RPM but less thrust so that may be the way to go.

There is no shortage of thrust, that's for sure!



I need to go back and review to see if less pitch increases EGT or if I need

a little more. 

.....

Stuart



-- 	




Less pitch will actually increase your EGT.  You can try this test.  Fly straight and level watch EGT.  Push nose down to unload prop a little, simulating less pitch. Watch which way EGT goes.   It will go up.  

That's also your danger zone while decending at lower throttle you will be in that hot zone of 4500 rpm already, then with the added unloading of the prop during decent, you will see your EGT spike.   I will either throttle back more to get out of the zone or decend with more power.  Depends on my approach.



The ideal situation would be to get a jet needle with a different curve that didn't lean out at 4500rpm but so far I haven't found one.  There was talk about one on this forum a few years back.  I bought it and it was way too thick so I am back to stock.



I think the 3 blade on a Firefly is perfect.  Lots of climb performance but less top speed.  Like you found the top speed isn't as much fun anyway.  Seems uncomfortable.  It's much more comfortable in an enclosed cockpit where the wind, noise and buffetting are reduced but whats the fun in that?

_________________
Scott Olendorf
Original Firestar, Rotax 447, Powerfin prop
Schenectady, NY
http://sites.google.com/site/kolbfirestar/

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sat Apr 25, 2015 6:48 am Post subject: Re: Firefly/447 RPM question

If you have not seen this before, or if trying to figure out jetting and prop load seems non-intuitive, maybe this will help: http://oh2fly.net/oldpoops/pg11.htm

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

stuart(at)harnerfarm.net
Guest

Posted: Sat Apr 25, 2015 9:14 am Post subject: Firefly/447 RPM question

Ha! Yes, that is where I saw it before.  Just could not remember the

details.



Thanks for the link.  There are lots of other sources too, some I have read,

some not. This one is nice and concise with pictures even!



More flying, less thinking.



Thanks,



Stuart



--

stuart(at)harnerfarm.net
Guest

Posted: Sat Apr 25, 2015 9:14 am Post subject: Firefly/447 RPM question

That is exactly where it happens, powered back for descent. 



I guess that makes sense, energy not used by the prop gets dumped overboard

in the exhaust.



In any case, either getting out of the mid-range or adding a little "choke"

fixes it.



I get nice even temps on both cylinders everywhere but mid-range. The clip

was in the top slot and I dropped it to the second which is actually the

recommended starting point.



At this point I think it is dialed in fairly close and I don't want to make

any more changes until I can get some more hours on the engine, heck it is

still new. Also I have yet to fly it at temps above 70°, so I expect things

to change some as the weather warms. 



Probably the best thing to do would be quit thinking about flying and start

actually flying.  Not today though, cool, cloudy and windy.  



Thanks again,



Stuart



--

west1m

Joined: 19 Apr 2014
Posts: 155
Location: Hastings, MN

Posted: Mon Apr 27, 2015 4:53 am Post subject: Re: Firefly/447 RPM question

I just started flying my Firefly. It was running very hot 1200+ ish.

66' 30 pitch wooden prop. the prop is a bit under pitched as I can over rev it.

However, I saw a chart in Leading edge catalog that shows  a 155 main jet for a 447 with a silencer or a 165 jet with out. I only have a K&N type filter and it had the 155 Jet.

 I switched to a 162 jet and a moved the needle to the middle rich position and problem solved, low 1000 temps. I will likely put the needle back to the middle lean position.

_________________
West1m
Hastings, MN

neilsenrm(at)gmail.com
Guest

Posted: Mon Apr 27, 2015 6:50 am Post subject: Firefly/447 RPM question

I read an article a few years back from the guy that developed the EGT system. He said that he was against the idea that there be any number markings on the gage. The only information that was important is that the pilot can see quickly that the engine has been leaned too much. The result is a much quicker swing of the EGT than the CHT when leaning in flight. That is also how it is explained during my private pilot training.



So all this talk about adjusting the prop to get a specific EGT number just sounds funny. I fail to understand how a engine is better when the heat of the exhaust is captured more by the engine.

By all means get the prop loading right. Make sure the CHT temps are in line and the spark plugs read correctly (these are the important things). Again the EGT will tell you quickly when you have leaned the mixture too much.

As always worth what you paid of it.

Rick Neilsen

Redrive VW Powered MKIIIC

On Mon, Apr 27, 2015 at 8:53 AM, west1m <west1m(at)hotmail.com (west1m(at)hotmail.com)> wrote:

[quote]--> Kolb-List message posted by: "west1m" <west1m(at)hotmail.com (west1m(at)hotmail.com)>

 

 I just started flying my Firefly. It was running very hot 1200+ ish.

 66' 30 pitch wooden prop. the prop is a bit under pitched as I can over rev it.

 However, I saw a chart in Leading edge catalog that showsÂ  a 155 main jet for a 447 with a silencer or a 165 jet with out. I only have a K&N type filter.

 Â I switched to a 162 jet and a moved the needle to the middle rich position and problem solved, low 1000 temps. I will likely put the needle back to the middle lean position.

 

 --------

 West1m

 Hastings, MN

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=441368#441368

 

 

 

 

 

 

 

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 [b]

John Hauck

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

Posted: Mon Apr 27, 2015 7:06 am Post subject: Firefly/447 RPM question

Aluminum melts at 1221F.Â  Rotax two stroke EGT redline is 1200.Â  That's close to the melting point.Â  Instruments are not precision.Â  A tiny hot spot will melt a speck of the piston ring groove, enough to cause rings to stick and blow by, then seizure.

 

I am a fan of the four stroke.Â  They aren't as critical to tune as the two stroke.Â  They run well for me right out of the box.Â  Prop loading is not critical.

 

john h

mkIII

Titus, Alabama

 

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Rick Neilsen

Sent: Monday, April 27, 2015 9:50 AM

To: kolb-list(at)matronics.com

Subject: Re: Re: Firefly/447 RPM question



 

I read an article a few years back from the guy that developed the EGT system. He said that he was against the idea that there be any number markings on the gage. The only information that was important is that the pilot can see quickly that the engine has been leaned too much. The result is a much quicker swing of the EGT than the CHT when leaning in flight. That is also how it is explained during my private pilot training.

 



So all this talk about adjusting the prop to get a specific EGT number just sounds funny. I fail to understand how a engine is better when the heat of the exhaust is captured more by the engine.



 



By all means get the prop loading right. Make sure the CHT temps are in line and the spark plugs read correctly (these are the important things). Again the EGT will tell you quickly when you have leaned the mixture too much.



 



As always worth what you paid of it.



 



Rick Neilsen



Redrive VW Powered MKIIIC

 

On Mon, Apr 27, 2015 at 8:53 AM, west1m <west1m(at)hotmail.com (west1m(at)hotmail.com)> wrote:

--> Kolb-List message posted by: "west1m" <west1m(at)hotmail.com (west1m(at)hotmail.com)>



I just started flying my Firefly. It was running very hot 1200+ ish.

66' 30 pitch wooden prop. the prop is a bit under pitched as I can over rev it.

However, I saw a chart in Leading edge catalog that shows  a 155 main jet for a 447 with a silencer or a 165 jet with out. I only have a K&N type filter.

 I switched to a 162 jet and a moved the needle to the middle rich position and problem solved, low 1000 temps. I will likely put the needle back to the middle lean position.



--------

West1m

Hastings, MN





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=441368#441368



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

stuart(at)harnerfarm.net
Guest

Posted: Mon Apr 27, 2015 8:02 am Post subject: Firefly/447 RPM question

Not knowing a great deal about 2 stroke engines, I think the EGT limits are to keep the exhaust ports from burning out.Â  EGT is an indication of whether or not the combustion is taking place mostly in the cylinder or if it is spilling out into the exhaust. A charge of gas that is still burning when the piston goes past the exhaust port would kind of act like a cutting torch on the edges of the port.

 

On my 447 the only leaning is done with the clip on the needle (or swapping needles and or jets). You can make the mixture more rich by adding â€œchokeâ€, which is what I have done on a couple of occasions.Â  Of course, the ideal is to get the engine to operate properly though the entire RPM range so you donâ€™t have to fiddle with things like the enricher while in the landing circuit.

 

I donâ€™t have anything against using the enricher when needed, and indeed that may be the best solution for me.Â  Maybe it will become part of my descent and landing procedure. Kind of like adding carb heat and going full rich when flying my old Cherokee. If that becomes the case, I may relocate the enricher lever to be down by the throttle so I am not reaching around blindly for a lever I canâ€™t see.

 

From what I can gather, prop loading/engine mixtures is more sensitive on little two strokes like the 447 and changes quite readily with temp and altitude. Trying to fly in 3 seasons may cause me to have to adjust things several times a year.

 

In any case, weather forecast is for flying conditions tomorrow.Â  Hopefully they are right this time, I am anxious to get back up and do some more experimenting.

 

Stuart

 

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Rick Neilsen

Sent: Monday, April 27, 2015 9:50 AM

To: kolb-list(at)matronics.com

Subject: Re: Re: Firefly/447 RPM question

 

I read an article a few years back from the guy that developed the EGT system. He said that he was against the idea that there be any number markings on the gage. The only information that was important is that the pilot can see quickly that the engine has been leaned too much. The result is a much quicker swing of the EGT than the CHT when leaning in flight. That is also how it is explained during my private pilot training.

 



So all this talk about adjusting the prop to get a specific EGT number just sounds funny. I fail to understand how a engine is better when the heat of the exhaust is captured more by the engine.



 



By all means get the prop loading right. Make sure the CHT temps are in line and the spark plugs read correctly (these are the important things). Again the EGT will tell you quickly when you have leaned the mixture too much.



 



As always worth what you paid of it.



 



Rick Neilsen



Redrive VW Powered MKIIIC

 

On Mon, Apr 27, 2015 at 8:53 AM, west1m <west1m(at)hotmail.com (west1m(at)hotmail.com)> wrote:

--> Kolb-List message posted by: "west1m" <west1m(at)hotmail.com (west1m(at)hotmail.com)>



I just started flying my Firefly. It was running very hot 1200+ ish.

66' 30 pitch wooden prop. the prop is a bit under pitched as I can over rev it.

However, I saw a chart in Leading edge catalog that shows  a 155 main jet for a 447 with a silencer or a 165 jet with out. I only have a K&N type filter.

 I switched to a 162 jet and a moved the needle to the middle rich position and problem solved, low 1000 temps. I will likely put the needle back to the middle lean position.



--------

West1m

Hastings, MN





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=441368#441368



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===========

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

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Herbgh(at)nctc.com
Guest

Posted: Mon Apr 27, 2015 8:13 am Post subject: Firefly/447 RPM question

remember also...Stuart...the engine is on the main jet from     somewhere beyondÂ  65 to 75 % throttle opening...before that you are     on the needle jet and needle..... Herb 

     

     On 04/27/2015 11:02 AM, Stuart Harner       wrote:

     

     [quote]                       <![endif]-->   <![endif]-->                

Not             knowing a great deal about 2 stroke engines, I think the EGT             limits are to keep the exhaust ports from burning out.Â  EGT             is an indication of whether or not the combustion is taking             place mostly in the cylinder or if it is spilling out into             the exhaust. A charge of gas that is still burning when the             piston goes past the exhaust port would kind of act like a             cutting torch on the edges of the port.         

Â          

On             my 447 the only leaning is done with the clip on the needle             (or swapping needles and or jets). You can make the mixture             more rich by adding â€œchokeâ€, which is what I have done on a             couple of occasions.Â  Of course, the ideal is to get the             engine to operate properly though the entire RPM range so             you donâ€™t have to fiddle with things like the enricher while             in the landing circuit.         

Â          

I             donâ€™t have anything against using the enricher when needed,             and indeed that may be the best solution for me.Â  Maybe it             will become part of my descent and landing procedure. Kind             of like adding carb heat and going full rich when flying my             old Cherokee. If that becomes the case, I may relocate the             enricher lever to be down by the throttle so I am not             reaching around blindly for a lever I canâ€™t see.         

Â          

From             what I can gather, prop loading/engine mixtures is more             sensitive on little two strokes like the 447 and changes             quite readily with temp and altitude. Trying to fly in 3             seasons may cause me to have to adjust things several times             a year.         

Â          

In             any case, weather forecast is for flying conditions             tomorrow.Â  Hopefully they are right this time, I am anxious             to get back up and do some more experimenting.         

Â          

Stuart         

Â          

From:             owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com)             [mailto:owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com)] On Behalf               Of Rick Neilsen

             Sent: Monday, April 27, 2015 9:50 AM

             To: kolb-list(at)matronics.com (kolb-list(at)matronics.com)

             Subject: Re: Re: Firefly/447 RPM question         

Â                     

I read an article a few years back from             the guy that developed the EGT system. He said that he was             against the idea that there be any number markings on the             gage. The only information that was important is that the             pilot can see quickly that the engine has been leaned too             much. The result is a much quicker swing of the EGT than the             CHT when leaning in flight. That is also how it is explained             during my private pilot training.                        

Â            

                        

So all this talk about adjusting the               prop to get a specific EGT number just sounds funny. I               fail to understand how a engine is better when the heat of               the exhaust is captured more by the engine.           

                        

Â            

                        

By all means get the prop loading               right. Make sure the CHT temps are in line and the spark               plugs read correctly (these are the important things).               Again the EGT will tell you quickly when you have leaned               the mixture too much.           

                        

Â            

                        

As always worth what you paid of it.           

                        

Â            

                        

Rick Neilsen           

                        

Redrive VW Powered MKIIIC           

         

                    

Â                         

On Mon, Apr 27, 2015 at 8:53 AM, west1m               <west1m(at)hotmail.com (west1m(at)hotmail.com)>               wrote:             

-->               Kolb-List message posted by: "west1m" <west1m(at)hotmail.com (west1m(at)hotmail.com)>

               

               I just started flying my Firefly. It was running very hot               1200+ ish.

               66' 30 pitch wooden prop. the prop is a bit under pitched               as I can over rev it.

               However, I saw a chart in Leading edge catalog that showsÂ                a 155 main jet for a 447 with a silencer or a 165 jet with               out. I only have a K&N type filter.

               Â I switched to a 162 jet and a moved the needle to the               middle rich position and problem solved, low 1000 temps. I               will likely put the needle back to the middle lean               position.

               

               --------

               West1m

               Hastings, MN

               

               

               

               

               Read this topic online here:

               

               http://forums.matronics.com/viewtopic.php?p=441368#441368

               

               

               

               

               

               

               

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stuart(at)harnerfarm.net
Guest

Posted: Mon Apr 27, 2015 8:25 am Post subject: Firefly/447 RPM question

Absolutely. I am shooting for high 1100â€™s EGT and mid 300â€™s for CHT. I think the 2 stroke is a fine line dance between shock cooling and burning up. Carefully monitored and well maintained the little Rotax would seem to be capable of going beyond what the factory says it will, but make any mistakes and you are looking for a place to land!

 

The Rotax guy from LEAF told us at OSH that 1250Â° was the absolute top red line limit. Since my manual has no listing for max EGT, I will defer to the factory certified guy. Consequently, I have my EIS limit set to 1225Â°.

 

If I could find a viable 4 stroke to put on a Firefly and keep it Part 103, I would buy it in a heartbeat.

 

Of course, 2 HP from every cubic inch of displacement on .01 GPH is every pilots wet dream, right?Â  Now where did I leave that box of di-lithium crystals and that bottle of anti-matter?

 

Anyway, I think there may be a future in electric motors for the Firefly. They are getting close to having reliable long lasing batteries. The motors and controllers already exist. If you can get a battery that will run a 30 HP motor for an hour with some left in reserve that does not cost $45K and weigh 100#, we will be in business.

 

Stuart

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of John Hauck

Sent: Monday, April 27, 2015 10:06 AM

To: kolb-list(at)matronics.com

Subject: RE: Re: Firefly/447 RPM question

 

Aluminum melts at 1221F.Â  Rotax two stroke EGT redline is 1200.Â  That's close to the melting point.Â  Instruments are not precision.Â  A tiny hot spot will melt a speck of the piston ring groove, enough to cause rings to stick and blow by, then seizure.

 

I am a fan of the four stroke.Â  They aren't as critical to tune as the two stroke.Â  They run well for me right out of the box.Â  Prop loading is not critical.

 

john h

mkIII

Titus, Alabama

 

From: owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com) [mailto:owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com)] On Behalf Of Rick Neilsen

Sent: Monday, April 27, 2015 9:50 AM

To: kolb-list(at)matronics.com (kolb-list(at)matronics.com)

Subject: Re: Re: Firefly/447 RPM question



 

I read an article a few years back from the guy that developed the EGT system. He said that he was against the idea that there be any number markings on the gage. The only information that was important is that the pilot can see quickly that the engine has been leaned too much. The result is a much quicker swing of the EGT than the CHT when leaning in flight. That is also how it is explained during my private pilot training.

 



So all this talk about adjusting the prop to get a specific EGT number just sounds funny. I fail to understand how a engine is better when the heat of the exhaust is captured more by the engine.



 



By all means get the prop loading right. Make sure the CHT temps are in line and the spark plugs read correctly (these are the important things). Again the EGT will tell you quickly when you have leaned the mixture too much.



 



As always worth what you paid of it.



 



Rick Neilsen



Redrive VW Powered MKIIIC

 

On Mon, Apr 27, 2015 at 8:53 AM, west1m <west1m(at)hotmail.com (west1m(at)hotmail.com)> wrote:

--> Kolb-List message posted by: "west1m" <west1m(at)hotmail.com (west1m(at)hotmail.com)>



I just started flying my Firefly. It was running very hot 1200+ ish.

66' 30 pitch wooden prop. the prop is a bit under pitched as I can over rev it.

However, I saw a chart in Leading edge catalog that shows  a 155 main jet for a 447 with a silencer or a 165 jet with out. I only have a K&N type filter.

 I switched to a 162 jet and a moved the needle to the middle rich position and problem solved, low 1000 temps. I will likely put the needle back to the middle lean position.



--------

West1m

Hastings, MN





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=441368#441368



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===========

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

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