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Thom Riddle

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

Posted: Mon Jul 16, 2007 9:05 am Post subject: FS 1 First Flight questions

I flew the new-to-me FS 1 / 447 this morning and discovered a couple things that I could use some help with. 

1) CHTs are low and EGTs are high during normal cruise speeds. They were in the normal range only during full power climb at Vy.



My conundrum: I believe that by increasing the prop pitch a bit this should improve both the CHT and EGT readings. However, its current pitch gives me 6,500 rpm at WOT in level flight, which I've always thought was just about right. The prop is a 2-blade Powerfin x 62".



What should I do?



2) With cruise power (5800 and higher), the elevator seems to be trimmed at higher IAS than I want or expect, i.e. it wants to descend with hands off. At lower power settings it seems to be trimmed at about 50 mph IAS, which I like. Is this an engine tilt(inclination) problem or something else?



I don't recall either of these situations in my old early FS. It was trim neutral at all speeds and EGTs and CHTs stayed in normal even when descending at low power.



Thanks for any guidance.

_________________
Thom Riddle
Buffalo, NY (9G0)

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

jindoguy(at)gmail.com
Guest

Posted: Mon Jul 16, 2007 10:11 am Post subject: FS 1 First Flight questions

Sounds like you might want to check the carb needle for the position of the clip. If it's not where Rotax or Bing recommends, put it back there. Since this is a new engine to you, check to see that the needle doesn't easily rotate in the groove, that the little O-ring is in place, and the plastic shoe has the relief for the O-ring. And of course, the needle goes in before the plastic shoe. 

If all the above are per spec, try raising the clip one notch (lowering the needle and leaning the midrange) and monitor CHT and EGT. CHT should go up and EGT should come down.



Rick



 On 7/16/07, Thom Riddle <riddletr(at)gmail.com (riddletr(at)gmail.com)> wrote: 	  Quote: 	
		   --> Kolb-List message posted by: "Thom Riddle" <riddletr(at)gmail.com (riddletr(at)gmail.com)>



I flew the new-to-me FS 1 / 447 this morning and discovered a couple things that I could use some help with. 

1) CHTs are low and EGTs are high during normal cruise speeds. They were in the normal range only during full power climb at Vy.



My conundrum: I believe that by increasing the prop pitch a bit this should improve both the CHT and EGT readings. However, its current pitch gives me 6,500 rpm at WOT in level flight, which I've always thought was just about right. The prop is a 2-blade Powerfin x 62". 



What should I do?



2) With cruise power (5800 and higher), the elevator seems to be trimmed at higher IAS than I want or expect, i.e. it wants to descend with hands off. At lower power settings it seems to be trimmed at about 50 mph IAS, which I like. Is this an engine tilt(inclination) problem or something else? 



I don't recall either of these situations in my old early FS. It was trim neutral at all speeds and EGTs and CHTs stayed in normal even when descending at low power.



Thanks for any guidance.



-------- 

Thom in Buffalo

N197BG FS1/447

do not archive

--------------------

&quot;Blind respect for authority is the greatest enemy of truth.&quot;

Albert Einstein





Read this topic online here: 



	


-- 

Rick Girard

"Ya'll drop on in"

takes on a whole new meaning

when you live at the airport.  [quote][b]

Thom Riddle

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

Posted: Mon Jul 16, 2007 10:22 am Post subject: Re: FS 1 First Flight questions

Rick,



If what you suggest leans the mixture at mid-range (it will), then the EGT's would go up, no? 



Thom in Buffalo

lcottrell

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

Posted: Mon Jul 16, 2007 10:31 am Post subject: FS 1 First Flight questions

[quote]    try raising the clip one notch (lowering the needle and leaning the    midrange) and monitor CHT and EGT. CHT should go up and EGT should come    down.



    

   Isn't this backwards? If his CHT's are high now in midrange,    it would seem to follow that he needs more fuel to cool it down.    

   Larry C 

[b]

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Jul 16, 2007 10:39 am Post subject: Re: FS 1 First Flight questions

The trim problem you are having is from flying a high thrust mounted pusher airplane, that is normal for that plane.   The more thrust you have, the more the plane will tend to pitch down.  Take off the power, and the airplane goes up.  This has nothing to do with the thrust angle, its easier than that.  All you need to trim the elevator to fly straight and level with cruise power and speed.  My MK III has a spring trim system, I just put in some nose up trim for level flight at cruise power setting.



Mike

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

Kolb MK-III Xtra, 912-S

Richard Pike

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

Posted: Mon Jul 16, 2007 2:03 pm Post subject: FS 1 First Flight questions

1) Put a bit more pitch in the prop. It is true that 6500 is the ideal RPM, 

however you won't hurt anything by adding some pitch, and that will both 

raise your CHT and lower your EGT. Dropping the needle one clip lower as 

someone else suggested will raise both your CHT and EGT.

If you try a bit of pitch and don't like the results, you haven't hurt 

anything.



2) Try a couple extra washers under the aft end of the engine. If you don't 

like it, put it back like it was.



Richard Pike

MKIII N420P (420ldPoops)



---

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

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

jindoguy(at)gmail.com
Guest

Posted: Mon Jul 16, 2007 3:31 pm Post subject: FS 1 First Flight questions

Larry, The condition Thom quoted was low CHT's and high EGT's with the prop pitched correctly. Since the aircraft is new to Thom, the first thing to verify is that everything is set up stock and the easiest thing to check, in my humble opinion, is the needle setting and the correctness of the needle setup. Also, he says the temps are all good when at WOT. This suggests that the main jet is stock or very close to it. 

All the things I listed should be checked immediately after purchase on any engine carrying Bing carbs and annually thereafter to insure that the needle is protected from vibration damage. All but one of my aircraft engines came with some portion of the vibration preventatives missing or installed incorrectly. The 582 I inspected at Sun n Fun had damage to both needles, one almost to the point of failure. When that happens the fire goes out. So, my idea was, why not do the easy inspection of a known problem area first, make sure all the jetting is stock and move on from there, once it's certain everything is up to snuff? Even if you have to replace every piece I mentioned, it's only about $50 a carb, so it's probably the cheapest potential life saving repair you'll ever do, too. 



Rick



On 7/16/07, Larry Cottrell <lcottrell(at)fmtcblue.com (lcottrell(at)fmtcblue.com)> wrote:[quote]         

 [quote]    try raising the clip one notch (lowering the needle and leaning the    midrange) and monitor CHT and EGT. CHT should go up and EGT should come    down.



    

   Isn't this backwards? If his CHT's are high now in midrange,    it would seem to follow that he needs more fuel to cool it down.    

   Larry C 

[b]  http://www.matronics.com/Navigator?Kolb-List http://forums.matronics.com 

when you live at the airport.  [quote][b]

jindoguy(at)gmail.com
Guest

Posted: Mon Jul 16, 2007 3:35 pm Post subject: FS 1 First Flight questions

I guess my logic would be that there is less fuel being burned on the way out the exhaust port making the EGT go down or remain unchanged. 



Rick



On 7/16/07,  Thom Riddle <riddletr(at)gmail.com (riddletr(at)gmail.com)> wrote:[quote] --> Kolb-List message posted by: "Thom Riddle" <riddletr(at)gmail.com (riddletr(at)gmail.com)>



Rick,



If what you suggest leans the mixture at mid-range (it will), then the EGT's would go up, no? 



Thom in Buffalo





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=124123#124123



 

when you live at the airport.  [quote][b]

Thom Riddle

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

Posted: Mon Jul 16, 2007 3:50 pm Post subject: Re: FS 1 First Flight questions

Thanks for all the pointers.  My plan is to try one thing at a time and see what the results are and change it back and try another if the previous made it worse or didn't improve it. 



I'll let you know what each change did for our collective education.

_________________
Thom Riddle
Buffalo, NY (9G0)

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

John Hauck

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

Posted: Mon Jul 16, 2007 4:01 pm Post subject: FS 1 First Flight questions

|I guess my logic would be that there is less fuel being burned on the 

way

| out the exhaust port making the EGT go down or remain unchanged.

|

| Rick

Rick/Richard:



My experience with 2 strokes has been:



1-Unload the prop, EGT goes up.



2-Load the prop, EGT goes down.



How did I discover this?  Watching the EGT on my Ultrastar in 1984, as 

I pulled the nose up and loaded the prop, and pushed the nose over and 

unloaded the prop.



3-Lean it midrange, EGT goes up.  Richen it up in midrange, EGT goes 

down.



4-Full throttle is same as midrange.



Finally, I don't worry about CHT, except to keep it under the red 

line.



My experience and opinion only.  The two stroke operates best when it 

is pitched to turn max continuous rpm, WOT, straight and level flight. 

I find the EGT will be right in the ball park, and one will experience 

the best climb and cruise with a prop that is not "in flight 

adjustable."



I prop my boats the same way as I do my airplanes.  Gives me the best 

"out of the hole" and cruise performance.



For what it is worth,



john h

mkIII

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

Thom Riddle

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

Posted: Mon Jul 16, 2007 4:53 pm Post subject: Re: FS 1 First Flight questions

John,



Thanks. That is what I was thinking. Unfortunately, with the prop pitched for WOT level flight at 6500 RPM (max continuous), I get very high EGTs. I'm going to try lowering the clip one notch so as not to loose the 6500 rpm during WOT. IF that solves it, then I couldn't have asked for a simpler solution. I'll post the results.

_________________
Thom Riddle
Buffalo, NY (9G0)

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

grabo172

Joined: 10 Oct 2006
Posts: 32
Location: Beaver, OH

Posted: Mon Jul 16, 2007 5:00 pm Post subject: Re: FS 1 First Flight questions

Thom,



Your carb needle is set at the second from the bottom, o-ringed in place and under the cup.  I put it there a few weeks ago.



I've been researching the EGT for the last year, and if you notice in the Rotax manual for the 447, they don't give an EGT spec... just a CHT.  



I've even talked to a few Rotax repairman about it and they say as long as the CHT is OK, you are pitched for 6500 RPM at WOT,  that's OK.  



With that advice and the manual not having the EGT limit for the 447, I felt confident in the engine.



When it all comes down to it, it is what YOU feel comfortable with.  



Hope that helps a little. (at least about where your needle is set)



P.S.

Besides the two issues above, how did you like her?

_________________
-Erik Grabowski
N?????
CFI/CFII/LS-I

Earl Zimmerman

Joined: 13 Jan 2006
Posts: 35
Location: Elizabethtown, PA

Posted: Mon Jul 16, 2007 6:17 pm Post subject: FS 1 First Flight questions

grabo172 wrote:

 	  Quote: 	
		   

 

 Thom,

 

 Your carb needle is set at the second from the bottom, o-ringed in place and under the cup.  I put it there a few weeks ago.

 

 I've been researching the EGT for the last year, and if you notice in the Rotax manual for the 447, they don't give an EGT spec... just a CHT.  

 

 I've even talked to a few Rotax repairman about it and they say as long as the CHT is OK, you are pitched for 6500 RPM at WOT,  that's OK.  

 

 With that advice and the manual not having the EGT limit for the 447, I felt confident in the engine.

 

 When it all comes down to it, it is what YOU feel comfortable with.  

 

 Hope that helps a little. (at least about where your needle is set)

 

 --------

 -Erik Grabowski

 N?????

 CFI/CFII/LS-I

 


	


That's exactly how the local 447 drivers around here do it. Jet and Prop 

by the book and forget the EGT. ~ Earl

Thom Riddle

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

Posted: Tue Jul 17, 2007 3:32 am Post subject: Re: FS 1 First Flight questions

Erik,



I believe that the absence of an explicit EGT range specification for the 447 in the Rotax 2-stroke Operators Manual was an accidental omission, not an indication that this particular engine has no limits. Since all the air-cooled Rotax aircraft engines are built similarly using similar technologies, I am taking the 503 numbers, a close relative of the 447, as proxy for the 447 in regards to normal EGT range. I am getting mid-range EGTs around 1200-1250 and that is too hot for this engine.



For what its worth:

1- Mike Stratman of CPS, says that 1200F EGT is too hot.

2- Rotax-service.com says that the normal EGT range for all Rotax aircooled engines is 860-1080F with a max of 1200F. 

3- I don't know what the Rotax gurus at Lockwood etc say but I will find out.

_________________
Thom Riddle
Buffalo, NY (9G0)

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

jindoguy(at)gmail.com
Guest

Posted: Tue Jul 17, 2007 5:00 am Post subject: FS 1 First Flight questions

Thom, I checked the Bing manual for the proper clip position on the needle of the type 54 carb. All versions of the 447 should have the clip set to the #2 position (from the top), unless you have the 447DC without the intake silencer installed, then it goes to #3.  

It should be noted that the 447DC w/o silencer uses a different needle (6G1) than the other models (15K2). 

447 and 447DC with the silencer use the same needle, but a different needle jet. The 447 uses a 2.70 needle jet, the 447DC uses a  2.68.

Hope this helps.



Rick

On 7/17/07, Thom Riddle <riddletr(at)gmail.com (riddletr(at)gmail.com)> wrote:[quote] --> Kolb-List message posted by: "Thom Riddle" <riddletr(at)gmail.com (riddletr(at)gmail.com)>



Erik,



I believe that the absence of an explicit EGT range specification for the 447 in the Rotax 2-stroke Operators Manual was an accidental omission, not an indication that this particular engine has no limits. Since all the air-cooled Rotax aircraft engines are built similarly using similar technologies, I am taking the 503 numbers, a close relative of the 447, as proxy for the 447 in regards to normal EGT range. I am getting mid-range EGTs around 1200-1250 and that is too hot for this engine. 



For what its worth:

1- Mike Stratman of CPS, says that 1200F EGT is too hot.

2- Rotax-service.com says that the normal EGT range for all Rotax aircooled engines is 860-1080F with a max of 1200F. 

3- I don't know what the Rotax gurus at Lockwood etc say but I will find out.



--------

Thom in Buffalo

N197BG FS1/447

do not archive

--------------------

&quot;Blind respect for authority is the greatest enemy of truth.&quot; 

Albert Einstein





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=124307#124307





 

when you live at the airport.  [quote][b]

Richard Pike

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

Posted: Tue Jul 17, 2007 5:59 am Post subject: FS 1 First Flight questions

Been thinking about this and came up with a theory I'll throw out for 

appropriate abuse:

While it is SOP that a correctly propped engine will give you good EGT's and 

CHT's while bumping red line in level flight, what would be your results if 

the prop diameter was slightly excessive for your engine?



Here is my thinking (your results may vary): if the diameter is slightly too 

large, then in order to get the engine to turn it's appropriate max RPM, 

(say 6500) you would need to dial in slightly less pitch than normal, due to 

the excess load imposed by the excess diameter. Then when reducing the RPM 

to cruise, the prop is now somewhat under pitched, and the EGT is going to 

be abnormally high, and the CHT abnormally low.



 So relative to your situation, any way you can borrow a 2 blade 60" prop to 

compare and see what happens? Or even a 62" Warp or Ivo, just in case 

Powerfin (with it's thicker airfoil) is causing a slightly higher load, and 

requiring a slightly lower pitch?



Richard Pike

MKIII N420P (420ldPoops)



---

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

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

tlongo

Joined: 17 Jul 2007
Posts: 14

Posted: Tue Jul 17, 2007 6:03 am Post subject: Re: FS 1 First Flight questions

If EGT is okay at full throttle and too high at cruse that means your main jetting is good and needle too lean. Check the holes in sides of needle jet tube if they have a build up that will cause a lean mixture even if your needle is set in the correct clip setting. You can use a toothpick to clean the holes or a piece of wire then blow out with air. Worth a try, very easy to do.

Richard Pike

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

Posted: Tue Jul 17, 2007 7:13 am Post subject: FS 1 First Flight questions

Not necessarily. See here:

http://www.bcchapel.org/pages/0003/pg11.htm

Richard Pike

MKIII N420P (420ldPoops)

---

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

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

Eugene Zimmerman

Joined: 10 Jan 2006
Posts: 392

Posted: Tue Jul 17, 2007 9:13 am Post subject: FS 1 First Flight questions

Ok Guys,

  I’ll weigh in with my $.02 on this topic.



NEVER depend entirely on your EGT gauge to adjust your carburetor.   

Plug color is a better indication to go by along with using your  

primer to give an extra small shot of fuel. If the rpms increase with  

the extra fuel you are obviously lean of peak and should raise the  

needle to enrich the fuel mixture. If the extra shot of fuel slows  

the rpm or causes the engine to stumble you should lower the needle  

to lean the mixture.



If you do not have a primer, sell your  EGT gauge and get one.  Just  

kidding ,,,,,,, but do get one.



These EGT gauges are notoriously inaccurate.



Gene Z

On Jul 17, 2007, at 9:58 AM, Richard Pike wrote:



[quote] 



 Been thinking about this and came up with a theory I'll throw out  

 for appropriate abuse:

 While it is SOP that a correctly propped engine will give you good  

 EGT's and CHT's while bumping red line in level flight, what would  

 be your results if the prop diameter was slightly excessive for  

 your engine?



 Here is my thinking (your results may vary): if the diameter is  

 slightly too large, then in order to get the engine to turn it's  

 appropriate max RPM, (say 6500) you would need to dial in slightly  

 less pitch than normal, due to the excess load imposed by the  

 excess diameter. Then when reducing the RPM to cruise, the prop is  

 now somewhat under pitched, and the EGT is going to be abnormally  

 high, and the CHT abnormally low.



 So relative to your situation, any way you can borrow a 2 blade 60"  

 prop to compare and see what happens? Or even a 62" Warp or Ivo,  

 just in case Powerfin (with it's thicker airfoil) is causing a  

 slightly higher load, and requiring a slightly lower pitch?



 Richard Pike

 MKIII N420P (420ldPoops)



 ---

jindoguy(at)gmail.com
Guest

Posted: Tue Jul 17, 2007 9:19 am Post subject: FS 1 First Flight questions

Richard, Since we're talking theory I'd tend to agree with you, but as Yogi Berra once said, "In theory there is no difference between theory and practice, In practice, there is."

Yes the prop unloads, but two things happen to ameliorate the engine temps. One, the prop disk of the larger prop counters the thrust loss produced by the lower pitch angle, so the relative amount of work done by the engine remains pretty much the same. Two, the bleed over in the mid to high range circuits of the carb, tends to lean out the carb as RPM drops. Rotax and Bing have worked this out by transition circuit design and jetting options. 



Rick



On 7/17/07, Richard Pike <richard(at)bcchapel.org (richard(at)bcchapel.org)> wrote:[quote] --> Kolb-List message posted by: "Richard Pike" <richard(at)bcchapel.org (richard(at)bcchapel.org)>



Been thinking about this and came up with a theory I'll throw out for

appropriate abuse: 

While it is SOP that a correctly propped engine will give you good EGT's and

CHT's while bumping red line in level flight, what would be your results if

the prop diameter was slightly excessive for your engine? 



Here is my thinking (your results may vary): if the diameter is slightly too

large, then in order to get the engine to turn it's appropriate max RPM,

(say 6500) you would need to dial in slightly less pitch than normal, due to 

the excess load imposed by the excess diameter. Then when reducing the RPM

to cruise, the prop is now somewhat under pitched, and the EGT is going to

be abnormally high, and the CHT abnormally low.



 So relative to your situation, any way you can borrow a 2 blade 60" prop to 

compare and see what happens? Or even a 62" Warp or Ivo, just in case

Powerfin (with it's thicker airfoil) is causing a slightly higher load, and

requiring a slightly lower pitch?



Richard Pike

 MKIII N420P (420ldPoops)



---

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