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RK400 clutch 582 application

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patreilly43(at)hotmail.co
Guest

Posted: Mon Feb 04, 2008 2:57 pm Post subject: RK400 clutch 582 application

Guy Bucahanan, You stated how much you like your  582 with the clutch. What about durning decent? Someone stated the clutch  does't disengage and drives the engine. Can you comment on this and more on any  drawbacks of the application. I know the benifits. Thank You 

  

 Pat Reilly 

 Mod 3 Rebuild

 Rockford, IL

   [quote][b]

Guy Buchanan

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

Posted: Mon Feb 04, 2008 6:03 pm Post subject: RK400 clutch 582 application

At 02:54 PM 2/4/2008, you wrote:

  	  Quote: 	
		  Guy Bucahanan, You stated how much you like your 582 with the clutch. What about durning decent? Someone stated the clutch does't disengage and drives the engine. 	


         That was me. Since I've never had an engine out or practiced by killing the engine I don't really know what will happen when the engine dies. I suppose it depends on whether I seize the engine, or run out of fuel, or loose an ignition module, or foul a plug. Other than the engine-out drag and the fact that it eventually wears out, (I don't know when,) I've found no problems. 

         Descent is Cessna-normal, unless you slow down so much that the prop disengages. Then the engine will drop to idle, (1500,) and the prop will windmill. The only way to do this is to slow to near stall speed.

         I really like having it. Starts are instantaneous and reliable, indeed if I sit for any length of time waiting for clearance I shut down the engine. It engages readily, but you have to be at about 2800 for full engagement. Between 2400 and 2800 it slips. If you want to taxi slow you have to use brakes, or go back and forth between idle and 2800.



 

 Guy Buchanan

 San Diego, CA

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

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

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Feb 04, 2008 7:20 pm Post subject: Re: RK400 clutch 582 application

[quote="patreilly43(at)hotmail.co"]Guy Bucahanan, You stated how much you like your  582 with the clutch. What about durning decent? Someone stated the clutch  does't disengage and drives the engine. Can you comment on this and more on any  drawbacks of the application. I know the benifits. Thank You 

  

 Pat Reilly 

 Mod 3 Rebuild

 Rockford, IL

    	  Quote: 	
		  [b] 	


The clutch will not drive the engine anymore than direct gears.  The only draw back, is the fact that you cant stop the prop from wind milling in the case of an engine out, and if you battery is dead you cant prop it.  Other than that there are NO drawbacks, only benefits IMO

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

avidfox

Joined: 03 Apr 2007
Posts: 87

Posted: Mon Feb 04, 2008 9:19 pm Post subject: RK400 clutch 582 application

"...you cant stop the prop from wind milling in the case of an engine out,..."

  

 Leni,

   Would it be possible to fabricate something like a simple helicopter style "rotor brake"  for just such an occasion?

 Has it been done before?

  or...Is it a totally stupid idea?

 Just thinking out loud here.....

  

 Steve

 84KF

  [quote][b]

akanka(at)kiamichiwb.org
Guest

Posted: Tue Feb 05, 2008 5:56 am Post subject: RK400 clutch 582 application

An opinion: It appears to me that the gearbox with a Sprague (or overrunning) clutch which is found in helicopters, on an engine drivetrain would be MUCH less drag in a dead engine situation than would a direct drive prop.  A dead direct drive engine will windmill at normal glide speeds so long as the internal components of the engine are intact (speaking from experience).  In order to stop a fixed pitch direct drive prop, the aircraft must be slowed well below best glide speed.  A controllable pitch prop, such as found on most multiengine planes, can be set to feather, which will cause it not windmill.    

   

In twin-engine engine out operations, the primary things to do after identifying which side has a dead engine is to maintain airspeed above VMC, apply full throttle to the good engine, clean up drag which is gear, flaps and feather the bad engine prop.  Quite a few twin engine airplanes will not climb at maximum gross takeoff weight until the bad engine’s prop is feathered.  The drag induced by a windmilling prop from  the compression, friction, and load of the accessories impose on a direct drive engine is FAR greater than a freewheeling prop.    

   

As for the “rotor brake” idea, it would work to stop a windmilling, non-feathering prop, but I think the blades would then impose more drag than they would if windmilling.   The effect would be similar to sticking a 2” X 4”  with the 4” side vertical out either side of the cockpit the distance of the prop blade length.  The only advantage I could see is that stopping the prop may help prevent damage to the prop itself in the event of gear failure during landing.  

   

John Hart  

Model IV N44CN  

Oklahoma    

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of 84KF

 Sent: Monday, February 04, 2008 11:17 PM

 To: kitfox-list(at)matronics.com

 Subject: Re: Re: RK400 clutch 582 application  

  

     

"...you cant stop the prop from wind milling in the case of an engine out,..."  

    

   

    

Leni,  

    

  Would it be possible to fabricate something like a simple helicopter style "rotor brake"  for just such an occasion?  

    

Has it been done before?  

    

 or...Is it a totally stupid idea?  

    

Just thinking out loud here.....  

    

   

    

Steve  

    

84KF  

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       [quote][b]

Tom Jones

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

Posted: Tue Feb 05, 2008 6:41 am Post subject: Re: RK400 clutch 582 application

 	  Quote: 	
		  The drag induced by a windmilling prop from the compression, friction, and load of the accessories impose on a direct drive engine is FAR greater than a freewheeling prop. 



As for the â€œrotor brakeâ€ idea, it would work to stop a windmilling, non-feathering prop, but I think the blades would then impose more drag than they would if windmilling. 	




Actually it is just the opposite.  A freewheeling prop produces much more drag than  a stopped prop or one windmilling at reduced engine speed.



With the gearbox clutch, if the engine stops and the prop freewheels, your options for landing areas is greatly reduced.  It would be good for the pilot to know how much drag the freewheeling prop produces and know what to expect when it happens.

_________________
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: Tue Feb 05, 2008 8:05 am Post subject: RK400 clutch 582 application

At 05:53 AM 2/5/2008, you wrote:

 	  Quote: 	
		  The drag induced by a windmilling prop from  the compression, 

friction, and load of the accessories impose on a direct drive 

engine is FAR greater than a freewheeling prop.


	


         Two possible ways to think about this, John. First, think 

about what helicopters do when they auto-rotate. As they pick up 

blade speed their vertical descent speed decreases. (You can also see 

this by making a paper helicopter. As they spin up they slow down.)

         Second, for the engineering types remember that lift is 

proportional to lift coefficient (Cl), blade area, density, and the 

SQUARE of the velocity. Pushed blades are just lifting in reverse 

(bad Cl) so area and density remain constant. Now Cl decreases as the 

prop speeds up, (lower angle of attack,) but it's variance is linear, 

and is overwhelmed by the squared velocity term. The faster the prop 

spins, the greater the lift (drag).

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.

JohnA

Joined: 22 Dec 2007
Posts: 26
Location: Woodland, CA

Posted: Tue Feb 05, 2008 2:23 pm Post subject: RK400 clutch 582 application

In the case of the RK-400 clutch, the speed of the prop turning has no bearing on the engagement of the clutch.  It is the engine speed that determines when the clutch engages/disengages.  In a descent with the engine RPM below the engagement threshold of the clutch or in the case of a stopped engine, the prop will freewheel.  It is known that a freewheeling prop has higher drag than one that is stationary.   The purpose of the RK-400 clutch is to make starting easier and reduce wear on the gearbox and engine during that start.  Everyone who has driven a 2-stroke knows how they rattle and gripe below 2500 rpm or so.  This is due to the load of the prop.  Prop load at start becomes a non-issue with the clutch, so starts are easier and smoother - especially if you have pull start.  As for not being able to prop your engine with the clutch, it is most unlikely that one will be able to prop start a 582 with a ducati ignition.  The ducati ignition doesn't start to develop a spark until around 800 engine rpm or thereabouts.  This translates to about 300 prop rpm.  One important note:  If you use a clutch, make sure to warm up the engine thoroughly at an engine rpm at which the prop is being driven (3000 is a good number).  You need that prop load on the engine so it generates enough heat to become thoroughly heat soaked before piling on the coal for a takeoff.  Lastly, if you use the E-box on your engine, you cannot use the RK-400 clutch -- unless you shift to a mag end starter or use the pull start.  The RK-400 will decouple the starter on the E-box from the engine.  All that will happen is you'll spin your prop but not the engine.  With the RK-400 clutch, you are limited to the C-box.   John Alexander Woodland, CA     On Mon, 4 Feb 2008 16:54:47 -0600, Pat Reilly wrote > Guy Bucahanan, You stated how much you like your   582 with the clutch. What about durning decent? Someone stated the clutch   does't disengage and drives the engine. Can you comment on this and more on any   drawbacks of the application. I know the benifits. Thank You    >    > Pat Reilly    > Mod 3  Rebuild  > Rockford,  IL   	  Quote: 	
		  



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_________________
John Alexander
Woodland, CA

Guy Buchanan

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

Posted: Tue Feb 05, 2008 7:09 pm Post subject: RK400 clutch 582 application

At 02:20 PM 2/5/2008, you wrote:

 	  Quote: 	
		  In a descent with the engine RPM below the engagement threshold of 

the clutch or in the case of a stopped engine, the prop will 

freewheel.  It is known that a freewheeling prop has higher drag 

than one that is stationary.


	


         Just to clarify. If I pull the throttle and descend, the 

engine will remain at some high idle or even higher RPM, being driven 

by the prop. If I slow until the engine RPM drops below 2400 it will 

immediately drop to 1500. I can then accelerate to any speed and the 

engine will remain at 1500, while the prop appears to spin like 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.

JohnA

Joined: 22 Dec 2007
Posts: 26
Location: Woodland, CA

Posted: Tue Feb 05, 2008 7:35 pm Post subject: RK400 clutch 582 application

This certainly makes sense, since the RK-400 clutch is set to disengage at

about 2500 rpm.  I'm guessing that with older ones, the springs that hold the

slipper shoes back at low rpm get tired and so engage and disengage at lower rpm.

But yes, as long as the engine rpm is below the engagement rpm for the clutch,

the prop will go to town - spinning freely.

Please do take note of my aside on warming the engine with the clutch

installed.  I repair more than a few cold seizured engines every year.  This

is something that is completely avoidable, but becomes something to always

keep in mind when using the RK-400 clutch, since the engine can operate at

very low rpm and load factors.  Long, low power descents followed by a

go-around is where you will get bit here.

John Alexander

On Tue, 05 Feb 2008 19:02:32 -0800, Guy Buchanan wrote

 	  Quote: 	

 At 02:20 PM 2/5/2008, you wrote:

 >In a descent with the engine RPM below the engagement threshold of 

 >the clutch or in the case of a stopped engine, the prop will 

 >freewheel.  It is known that a freewheeling prop has higher drag 

 >than one that is stationary.

          Just to clarify. If I pull the throttle and descend, the 

 engine will remain at some high idle or even higher RPM, being 

 driven by the prop. If I slow until the engine RPM drops below 2400 

 it will immediately drop to 1500. I can then accelerate to any speed 

 and the engine will remain at 1500, while the prop appears to spin 

 like crazy.

 Guy Buchanan

 San Diego, CA

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

--

Beer is proof that god loves us and wants us to be happy.  - Ben Franklin

_________________
John Alexander
Woodland, CA

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Wed Feb 06, 2008 3:33 am Post subject: RK400 clutch 582 application

I wonder how many RPM the prop willl take before being damaged. 



Dave Goddard- Mod IV 1050/582

do not archive



. I can then accelerate to any speed 

 	  Quote: 	
		  > and the engine will remain at 1500, while the prop appears to spin 

> like crazy.

> 

> Guy Buchanan

> San Diego, CA

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

> 

 

 

 --

 Beer is proof that god loves us and wants us to be happy.  - Ben Franklin

Guy Buchanan

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

Posted: Wed Feb 06, 2008 8:12 am Post subject: RK400 clutch 582 application

At 03:31 AM 2/6/2008, you wrote:

 	  Quote: 	
		  I wonder how many RPM the prop willl take before being damaged.


	


         LOL! I wondered about that when I was testing. Needless to 

say I didn't push it. However I don't think there's any worry. The 

prop will always spin faster pulling than pushing, since slippage 

works against you both ways. (Meaning, it slips when generating 

thrust, and slips worse when being thrust because of the lousy airfoil.)

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 Feb 06, 2008 9:24 am Post subject: Re: RK400 clutch 582 application

 	  Quote: 	
		  LOL! I wondered about that when I was testing. Needless to 

say I didn't push it. However I don't think there's any worry. The 

prop will always spin faster pulling than pushing, since slippage 

works against you both ways. 	




Maybe you can do the math for RPM, pitch and speed to get an idea of RPMs with the slippage being a safety factor.  Pitch = distance traveled through the air in one revolution.

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

msm_9949(at)yahoo.com
Guest

Posted: Wed Feb 06, 2008 10:05 am Post subject: RK400 clutch 582 application

Low-power descents are where Lowell's rad shutters save the day. Adjust the shutters as needed to keep temps above 140 degrees. They work like a charm. They also help get the temps up faster on the ground. An easy, inexpensive mod that I highly recommend, whether or not you have the RK400 installed.

  http://highwingllc.com/

John Alexander <alexandj(at)preachain.org> wrote: 

  [quote]--> Kitfox-List message posted by: "John Alexander" 

This certainly makes sense, since the RK-400 clutch is set to disengage at

about 2500 rpm. I'm guessing that with older ones, the springs that hold the

slipper shoes back at low rpm get tired and so engage and disengage at lower rpm.

But yes, as long as the engine rpm is below the engagement rpm for the  clutch,

the prop will go to town - spinning freely.

Please do take note of my aside on warming the engine with the clutch

installed. I repair more than a few cold seizured engines every year. This

is something that is completely avoidable, but becomes something to always

keep in mind when using the RK-400 clutch, since the engine can operate at

very low rpm and load factors. Long, low power descents followed by a

go-around is where you will get bit here.

John Alexander

On Tue, 05 Feb 2008 19:02:32 -0800, Guy Buchanan wrote

[quote] --> Kitfox-List message posted by: Guy Buchanan 

 At 02:20 PM 2/5/2008, you wrote:

 >In a descent with the engine RPM below the engagement threshold of 

 >the clutch or in the case of a stopped engine, the prop will 

 >freewheel. It is known that a freewheeling prop has higher drag 

 >than one that is stationary.

 [quote][b]

avidfox

Joined: 03 Apr 2007
Posts: 87

Posted: Wed Feb 06, 2008 10:25 am Post subject: RK400 clutch 582 application

"Maybe you can do the math for RPM, pitch and speed to get an idea of RPMs with the slippage being a safety factor.  Pitch = distance traveled through the air in one revolution"

  

 

 

 Or..., just point an optical "checker" out the windshield. 

 [url=http://store.wagaero.com/product_info.php?products_id 933]http://store.wagaero.com/product_info.php?products_id 933[/url] 

  

 Occam's razor

 http://en.wikipedia.org/wiki/Occam's_Razor

  

 Steve

 84KF

  

  [quote][b]

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