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A Fun Flight

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Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Tue Nov 18, 2008 3:58 pm Post subject: A Fun Flight

All,

         We've been having the usually dreaded Santa Ana winds the 

last two days, with winds out of the east (offshore) blowing about 

20-40mph. While it makes great weather for burning mobile homes, it 

also, the day after, leaves us with 50 - 100 mile visibility under 

clear skies and calm winds. The visibility is a particular treat, 

since we normally have 5-10 mile visibility in haze due to the warm 

marine weather that makes San Diego so popular.

         Departing Ramona with no particular destination in mind I 

headed north to visit the east LA basin. When the smog's blown out 

after a Santa Ana it's a beautiful area, ringed by mountains, 11k' to 

the north and 10k' to the east. I decided I'd go to Hemet to check 

the restaurant that fairly recently re-opened. Traffic was 

non-existent, but I flew at 4500' since I was flying alone.

         Despite the warm weather I had a cup of chili and lemonade 

for lunch, served by a singing waitress. (Bengals - "All Over the 

Place") It cost all of $5, the cheapest flying lunch I've ever had. 

(Lessee, $5 + 1.5h (at) $67/hr = $105.50. Perfect!) Departing Hemet I 

thought, just for grins, I might see if there were any climbers on 

10.8k' San Jacinto: full throttle, hold it at 6200 rpm, lean with 

altitude, look for thermals and ridge lift, and the little beezer 582 

climbed right up to 11k'. Sure enough there was one hiker on the peak 

who offered a friendly wave. From my vantage at 11k' I could see all 

the way from Yuma to Edwards AFB to the ocean. Magnificent. It was so 

nice I flew all the way back to Ramona at 10.5k' enjoying the iPod in 

perfectly smooth, 60 degree, air. As is typical with the 582, I 

slam-dunked the descent to keep the EGT's in line. I learned a new 

trick, too. The Garmin Pilot III gps gives the vertical speed to the 

waypoint. I found I could maintain a perfect glide-slope if I kept 

the vertical speed constant. (Easier said than done.)

         No I didn't take any pictures. The problem is that they 

never come out as good as Michel's. Maybe next time.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.



Do not archive

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Tue Nov 18, 2008 6:34 pm Post subject: Re: A Fun Flight

Guy, that sounds like a fun time.  You mention leaning as you climbed.  do you have the Arctic Sparrow cockpit adjustable needles?



Also can you Tell more about the slam dunk method of descending to keep the EGT's in line?

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Wed Nov 19, 2008 8:23 am Post subject: A Fun Flight

At 06:34 PM 11/18/2008, you wrote:

 	  Quote: 	
		  You mention leaning as you climbed.  do you have the Arctic Sparrow 

cockpit adjustable needles?


	


         No, I have the HACman system that varies the float bowl 

pressure to achieve moderate leaning. I like it a lot.



 	  Quote: 	
		  Also can you Tell more about the slam dunk method of descending to 

keep the EGT's in line?


	


         With the HACman system you install rich mains, to give you 

something to lean off. I run 180's here in San Diego. The mid range 

is kept as-is so when you go moderately down hill you end up in the 

mid-range jets with the prop pushing the engine and therefore very 

lean. The only way to go down hill without getting too lean is to 

either go slow, or descend slowly, or pull the throttle way back and 

drop like a rock. Usually I do shallow controlled descents, but when 

I'm trying to stay with my 912 buddies, or the view is pretty, I 

stair-step down, dropping fast near idle, the levelling at cruise 

throttle. It drives them crazy!

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Wed Nov 19, 2008 11:50 am Post subject: Re: A Fun Flight

 	  Quote: 	
		  With the HACman system you install rich mains, to give you 

something to lean off. I run 180's here in San Diego. The mid range 

is kept as-is so when you go moderately down hill you end up in the 

mid-range jets with the prop pushing the engine and therefore very 

lean. The only way to go down hill without getting too lean is to 

either go slow, or descend slowly, or pull the throttle way back and 

drop like a rock. Usually I do shallow controlled descents, but when 

I'm trying to stay with my 912 buddies, or the view is pretty, I 

stair-step down, dropping fast near idle, the levelling at cruise 

throttle. It drives them crazy! 

Guy Buchanan 	




Thanks for the reply Guy.  I have the adjustable "Sparrow needles" and am still learning how to use them to keep the EGT's under control in a descent with partial power.



It is easy...for me anyhow...to get confused and forget how many turns on the needle adjustments I have made then which way to turn the knobs to correct a rough engine when I get it out of wack.

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

gary.algate(at)sandvik.co
Guest

Posted: Wed Nov 19, 2008 2:42 pm Post subject: A Fun Flight

Just for interest sake the IVO In-Flight adjustable prop also gives you good control over EGT's. 

 

By coarsing up in cruise you can lower the EGT's significantly and also by going to a fine pitch in descent helps lower EGT's 

 



 

 Gary Algate

 Classic4 Jab2200A

 

 

 This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission. 

 

 

 

    

 

 

 

"Tom Jones" <nahsikhs(at)elltel.net> 

Sent by: owner-kitfox-list-server(at)matronics.com 

20/11/2008 06:26 AM 

Please respond to

 kitfox-list(at)matronics.com     To

 kitfox-list(at)matronics.com   cc

    Subject

 Re: A Fun Flight 

     

 

 

 

--> Kitfox-List message posted by: "Tom Jones" <nahsikhs(at)elltel.net>

 

 

 > With the HACman system you install rich mains, to give you 

 > something to lean off. I run 180's here in San Diego. The mid range 

 > is kept as-is so when you go moderately down hill you end up in the 

 > mid-range jets with the prop pushing the engine and therefore very 

 > lean. The only way to go down hill without getting too lean is to 

 > either go slow, or descend slowly, or pull the throttle way back and 

 > drop like a rock. Usually I do shallow controlled descents, but when 

 > I'm trying to stay with my 912 buddies, or the view is pretty, I 

 > stair-step down, dropping fast near idle, the levelling at cruise 

 > throttle. It drives them crazy! 

 > Guy Buchanan 

 

 

 Thanks for the reply Guy.  I have the adjustable "Sparrow needles" and am still learning how to use them to keep the EGT's under control in a descent with partial power.

 

 It is easy...for me anyhow...to get confused and forget how many turns on the needle adjustments I have made then which way to turn the knobs to correct a rough engine when I get it out of wack.

 

 --------

 Tom Jones

 Classic IV

 503 Rotax, 72 inch Two blade Warp

 Ellensburg, WA

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p 15170#215170

 

 

 

 

 

 

 

          -Matt Dralle, List Admin.

 -

 

 

 

  

 [quote][b]

paul(at)eucleides.com
Guest

Posted: Wed Nov 19, 2008 4:01 pm Post subject: A Fun Flight

On Wed, November 19, 2008 8:12 am, Guy Buchanan wrote:

 	  Quote: 	
		   



 At 06:34 PM 11/18/2008, you wrote:


	


 	  Quote: 	
		            With the HACman system you install rich mains, to give you

 something to lean off. I run 180's here in San Diego. The mid range

 is kept as-is so when you go moderately down hill you end up in the

 mid-range jets with the prop pushing the engine and therefore very

 lean. The only way to go down hill without getting too lean is to

 either go slow, or descend slowly, or pull the throttle way back and

 drop like a rock. Usually I do shallow controlled descents, but when

 I'm trying to stay with my 912 buddies, or the view is pretty, I

 stair-step down, dropping fast near idle, the levelling at cruise

 throttle. It drives them crazy!


	


A prop clutch has been mentioned a few times on the list here. Wouldn't that solve

this problem and also make less engine shaking when you shut down too?



With a clutch on the prop it wouldn't drive the engine so lubrication would still be

maintained correctly.



Just a thought. Id like to know.



 	  Quote: 	
		  



 Guy Buchanan

 San Diego, CA

 K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.




	




-- 

Paul A. Franz, P.E.

PAF Consulting Engineers

Office 425.440.9505

Cell 425.241.1618

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Wed Nov 19, 2008 7:26 pm Post subject: A Fun Flight

At 04:01 PM 11/19/2008, you wrote:

 	  Quote: 	
		  With a clutch on the prop it wouldn't drive the engine so 

lubrication would still be

maintained correctly.


	


         The clutch is strictly centrifugal. Any time the engine's 

above 2700 rpm it's locked solid, regardless of whether the engine's 

doing the pushing or the prop. In order to get it to disengage in the 

air you have to slow to below about 50 mph, then it will disengage 

and you can descend with the engine at idle. I try not to do this 

because I worry about the instantaneous heating associated with 

re-engagement, when the engine rpm doesn't match the prop rpm very well.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

paul(at)eucleides.com
Guest

Posted: Wed Nov 19, 2008 9:18 pm Post subject: A Fun Flight

On Wed, November 19, 2008 5:48 pm, Guy Buchanan wrote:

 	  Quote: 	

 At 04:01 PM 11/19/2008, you wrote:

>With a clutch on the prop it wouldn't drive the engine so

>lubrication would still be

>maintained correctly.

          The clutch is strictly centrifugal. Any time the engine's

 above 2700 rpm it's locked solid, regardless of whether the engine's

 doing the pushing or the prop. In order to get it to disengage in the

 air you have to slow to below about 50 mph, then it will disengage

 and you can descend with the engine at idle. I try not to do this

 because I worry about the instantaneous heating associated with

 re-engagement, when the engine rpm doesn't match the prop rpm very well.

I didn't know that. I thought it was a dog and pawl setup. Anyway, it sounds to me as

long as the rpm difference is less than 2700 rpm then you'd be OK as apparently that's

what it's designed for. So, as an example, assume you slowed the engine and prop to

less than 2700 rpm so the clutch would disengage then let the engine go to idle, then

the resume descent then the prop rpm might go over 2700 rpm but wouldn't go so fast

that the tips went supersonic. You'd really hear that. You could calculate that rpm

given the diameter and assume that the speed of sound is 1100 fps.

Supersonic RPM = (1100 FPS * 60 Sec/Min) / (Dia [FT] * PI)

then say you had a 68" dia prop,

Supersonic RPM = (1100 * 60) / ((68/12) * 3.14159)

               = 3707 RPM

So, it would seem to me that as soon as you hit the throttle, the engine would not

engage the clutch until something just below 2700 rpm and the prop would not be going

more than 1000 rpm or so faster than that. You'd know for sure it was supersonic by

the really loud beating noise that happens when the prop tips go supersonic. You'd be

safe since you know the rpm difference can be 2700 as that is what you have when you

start the engine to begin with. Prop is going zero rpm and the engine gets close to

2700 rpm when the centrifugal clutch engages and that's apparently the design so I

don't think you'd have to worry about re-engaging the clutch when the rpm difference

is that low, albeit in this case the prop is going faster than the engine rather than

the engine going faster than the prop as in the case of start up. (Whew, long

sentence, should break it up)

My point is, that if you release the clutch in flight then re-engage, the load on the

clutch isn't going to be nearly as high as it is at start-up.

It would bother me to have the prop disengaged from the engine in flight because then

you're depending on the starter to work in case the engine dies and the windmilling

prop would be no assistance what-so-ever.

So, if you don't do your technique of descending in steps, what is the maximum descent

rate you can have to stay within recommended EGT and Cyl Hd temperatures at some low

power setting such as 25%? I could live with 1000 fpm descent fine and even 500 fpm

would be workable given the relatively low ground speed.

Some time back, actually many years ago, there was a debate about using pre-mix vs

auto oil injection. I thought that the auto oil injection was rpm dependent vs air

flow so that this effect would be automatically compensated for. Apparently not

because the EGT still is rising too high and the only way to control that is by adding

excess fuel. But maybe, when the engine isn't under load, the allowable EGT can be a

little higher. You're probably saying "not with my pistons!"

-- 

Paul A. Franz, P.E.

PAF Consulting Engineers

Office 425.440.9505

Cell 425.241.1618

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Thu Nov 20, 2008 9:17 am Post subject: A Fun Flight

At 09:18 PM 11/19/2008, you wrote:

 	  Quote: 	
		  My point is, that if you release the clutch in flight then 

re-engage, the load on the

clutch isn't going to be nearly as high as it is at start-up.


	


Your analysis is accurate as far as it goes, but there is a 

potentially significant difference between the two cases. In flight 

the prop is "loaded"; meaning it is "mechanically" connected to a 

fast moving air stream. It will resist any variation from it's 

equilibrium rpm. When you're on the ground there is no load at idle 

and little load at, say, 3000 rpm. I have never quantified the 

difference so I avoid testing in that regime.



 	  Quote: 	
		  It would bother me to have the prop disengaged from the engine in 

flight because then

you're depending on the starter to work in case the engine dies and 

the windmilling

prop would be no assistance what-so-ever.


	


You are anyway. With the 3:1 gearing and the wimpy Warp drive blades 

you'd have to loose all compression to turn the engine with the prop. 

I think there are several in the list who have shut down in flight 

and discovered this.



 	  Quote: 	
		  So, if you don't do your technique of descending in steps, what is 

the maximum descent

rate you can have to stay within recommended EGT and Cyl Hd 

temperatures at some low

power setting such as 25%? I could live with 1000 fpm descent fine 

and even 500 fpm

would be workable given the relatively low ground speed.


	


I think I can do around 400-500 fpm, but it's a cruise speed descent 

and slow relative to my fly-mates.



 	  Quote: 	
		  I thought that the auto oil injection was rpm dependent vs air

flow so that this effect would be automatically compensated for.


	


It is, but not by much. The main variation is that the oil injection 

reduces dramatically at idle. I've never seen the curve, but that's 

what I've been told.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Fri Nov 21, 2008 7:15 am Post subject: A Fun Flight

This is comparing apples with icicles, but just for kicks I shut my  

newly rebuilt engine (I mention this because it was still tight from  

the rebuild) off at a good altitude, and it wouldn't stop the prop,  

so I pointed the plane up until it did stop. Then I pointed it down  

to see if the wind would crank it over...it didn't, and I was not  

about to point it any more down or for very much longer, so I engaged  

the starter for the restart. Now this is a direct-drive engine, so  

the geared engines will take even more effort from the wind to get  

them to turn over. So we're comparing a stiff direct drive with a  

broken in geared drive, so there's no comparison, just food for thought.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, 591hrs

Sensenich 62x46

flying again after rebuild, and new Electroair direct-fire ignition  

system

do not archive

On Nov 20, 2008, at 12:09 PM, Guy Buchanan wrote:



 	  Quote: 	
		   



 You are anyway. With the 3:1 gearing and the wimpy Warp drive  

 blades you'd have to loose all compression to turn the engine with  

 the prop. I think there are several in the list who have shut down  

 in flight and discovered this.



 Guy Buchanan

 San Diego, CA

 K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Fri Nov 21, 2008 7:54 am Post subject: Re: A Fun Flight

At 45 mph on the trailer my prop rotates slowly.  It stops for a few seconds while the compression is evidently overcome then rotates and stops again for a few seconds on the next compression etc.  503 Rotax 3:1 gear box, 72 inch warp drive 2 blade prop.  I tie a rope to it to prevent the rotation.

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Fri Nov 21, 2008 8:16 am Post subject: A Fun Flight

You might consider getting new piston rings, Tom....just kidding. : )



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, 591hrs

Sensenich 62x46

flying again after rebuild, and new Electroair direct-fire ignition  

system

do not archive

On Nov 21, 2008, at 10:54 AM, Tom Jones wrote:



 	  Quote: 	
		   



 At 45 mph on the trailer my prop rotates slowly.  It stops for a  

 few seconds while the compression is evidently overcome then  

 rotates and stops again for a few seconds on the next compression  

 etc.  503 Rotax 3:1 gear box, 72 inch warp drive 2 blade prop.  I  

 tie a rope to it to prevent the rotation.



 I know not may 503's on a kitfox, not enough power.



 --------

 Tom Jones

 Classic IV

 503 Rotax, 72 inch Two blade Warp

 Ellensburg, WA





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 15544#215544

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

matronics(at)bob.brennan.
Guest

Posted: Fri Nov 21, 2008 8:44 am Post subject: A Fun Flight

I have the same thing happen when I trailer my KF2. The only problem for me

is that the clearance on my barn door [erstwhile hanger] isn't enough if one

blade is up, so I have to do a pre-hanger check lest I need to explain to my

insurance company how I had a prop strike on a barn door...



Also pre-trailer inspection includes mags OFF, throttle closed, and fuel

off; unless you want to start playing tug-of-war, tow-vehicle vs airplane,

in traffic!



Bob Brennan - N717GB 

1991 UK Model 2 ELSA Kitfox

Rotax 582 with 3 blade prop

Wrightsville Pa 



--

hlang(at)bluewin.ch
Guest

Posted: Sat Nov 22, 2008 1:01 am Post subject: A Fun Flight

Hello all  

Just to mention my own experience: Kitfox IV with 582 and 3:1 gear, switching off the engine and descending with 60 mph does turn the prop, but very slowly.  

Heinz Lang  

HB-YFS  

   

   

       [quote][b]

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