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Throttle Cables

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Kyle

Joined: 13 Jun 2008
Posts: 15
Location: Western Kentucky

Posted: Mon Jul 14, 2008 7:42 am Post subject: Throttle Cables

On my recently acquired Kitfox IV-1200 w/912UL the throttle cables were replaced and not adjusted before I bought it. I have adjusted the cables and synchronized the carbs. The throttle cables from the bell crank to the carburetor are stranded cables, not solid wire. Is this what it's suppose to have? It looks like there is a possibility of the cables flexing instead of being rigid enough to be able to push the carburetor arms forward. 

Thanks,

_________________
Kyle Dunn
Eddyville, Kentucky
Kitfox IV 1200 912 Rotax
1978 Cessna 172 N
American Aero Phoenix II w/582 Rotax
Rotorway Exec.

paul perry

Joined: 11 Jun 2008
Posts: 36

Posted: Mon Jul 14, 2008 6:04 pm Post subject: Re: Throttle Cables

Kyle, I too have recently purchased a KF IV 1200 with the 80hp Rotax and that is the same throttle cable wire I have. I have read several of the threads regarding the throttle springs (which are fairly forceful) and have concluded the following. The throttle springs assist in moving the throttle forward(open) and act as a safety feature in case the cable breaks, then they would move to full open. It has taken me some time to get use to the system and the required use and constant adjustment  of the friction lock depending on whether I'm taking off/cruise/ or landing modes..but have found it is doable. I think I would like a vernier setup, but I'm not sure how to set that up (parts needed etc) for a system with dual carbs.  Hope this helps, although I'm sure someone with more mechanical/technical knowledge and skills will probably answer your question more thoroughly.  By the way, I fly into KY Dam airport frequently so maybe I'll run (figurative) into you sometime. Paul Perry

Kyle

Joined: 13 Jun 2008
Posts: 15
Location: Western Kentucky

Posted: Tue Jul 15, 2008 5:15 am Post subject: Re: Throttle Cables

Paul, where do you fly out of?

It seems that the springs on my carburetors are not that strong. My concern was that in the heat of the moment, (a go around for example) it might be possible to overrun the throttle springs when going WOT and pinch the stranded cable and put a kink in it on the bell crank end.

I may be overly concerned for nothing.

Kyle

_________________
Kyle Dunn
Eddyville, Kentucky
Kitfox IV 1200 912 Rotax
1978 Cessna 172 N
American Aero Phoenix II w/582 Rotax
Rotorway Exec.

Lynn Matteson

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

Posted: Tue Jul 15, 2008 11:37 am Post subject: Throttle Cables

It doesn't seem to me to be such a difficult job to go to solid wire  

control "devices".....I've got a vernier throttle, solid wire, and it  

works perfectly. A simple splitter could be constructed to make a  

solid throttle control all the way to the carbs. The splitter could  

be in the form of a bellcrank.



Lynn Matteson

Kitfox IV Speedster

Jabiru 2200

Status: flying w/547+ hrs





On Jul 15, 2008, at 9:15 AM, Kyle wrote:



 	  Quote: 	
		   



 Paul, where do you fly out of?

 It seems that the springs on my carburetors are not that strong. My  

 concern was that in the heat of the moment, (a go around for  

 example) it might be possible to overrun the throttle springs when  

 going WOT and pinch the stranded cable and put a kink in it on the  

 bell crank end.

 I may be overly concerned for nothing.

 Kyle



 --------

 Kyle Dunn

 Eddyville, Kentucky

 Kitfox IV 1200 912 Rotax

 1978 Cessna 172 N

 American Aero Phoenix II w/582 Rotax

 Rotorway Exec.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=192829#192829

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

paul perry

Joined: 11 Jun 2008
Posts: 36

Posted: Tue Jul 15, 2008 3:16 pm Post subject: Re: Throttle Cables

Kyle, I live in southeast MO and fly out of Dexter,MO, but I've had a vacation home near Jonathan Creek the past several years and although it doesn't save me that much time to fly to m34 it's a lot more fun than driving. I've only had the KF for about a month and I'm not a builder or mechanic (good friend is though) so I'm not that familiar with how a vernier or solid wire  setup would need to be constructed, but I'm sure Lynn is correct and I did see a "splitter" on Aircraft Spruce's website. My system seems to be working ok right now, so I think I will put that modification down a few spots on my wish list. You might want to check out the Rotax discussion though, as I did see some discussion about the throttle springs and it's possible if you were not the builder that what you have are not the original springs which may or may not be a problem.

Kyle

Joined: 13 Jun 2008
Posts: 15
Location: Western Kentucky

Posted: Wed Jul 16, 2008 8:21 am Post subject: Re: Throttle Cables

I did find through research that in the early 90's there was a service bulletin issued saying that because of a couple of solid wire throttle cable failures it was recommended to convert to the 1/16" (7 x 7) Stainless Steel braided wire throttle cables. The thought was that the solid wire control work hardened over time due to vibration and use to cause the failure.

Thanks,

_________________
Kyle Dunn
Eddyville, Kentucky
Kitfox IV 1200 912 Rotax
1978 Cessna 172 N
American Aero Phoenix II w/582 Rotax
Rotorway Exec.

Lynn Matteson

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

Posted: Wed Jul 16, 2008 11:01 am Post subject: Throttle Cables

That sounds reasonable, Lyle, and with the "spring-to-open" throttles  

like the Bing carb has, I could see a cable doing the job, but  

history...at least my history of looking at them...has shown (me)  

that wire is the normal set-up. It depends partly on how many bends  

are to be made in the run from knob to throttle arm.

I wouldn't be at all against using a cable to *pull* the throttle  

open, but my "shadetree mechanical engineering degree" shudders at  

the thought of using a cable to *push* it open...assisted with the  

spring, ala Bing.



Lynn Matteson

Kitfox IV Speedster

Jabiru 2200

Status: flying w/547+ hrs





On Jul 16, 2008, at 12:21 PM, Kyle wrote:



 	  Quote: 	
		   



 I did find through research that in the early 90's there was a  

 service bulletin issued saying that because of a couple of solid  

 wire throttle cable failures it was recommended to convert to the  

 1/16" (7 x 7) Stainless Steel braided wire throttle cables. The  

 thought was that the solid wire control work hardened over time due  

 to vibration and use to cause the failure.

 Thanks,



 --------

 Kyle Dunn

 Eddyville, Kentucky

 Kitfox IV 1200 912 Rotax

 1978 Cessna 172 N

 American Aero Phoenix II w/582 Rotax

 Rotorway Exec.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=193118#193118

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

lcfitt(at)sbcglobal.net
Guest

Posted: Wed Jul 16, 2008 3:31 pm Post subject: Throttle Cables

Just a quick note.  With the Kitfox 912 set-up, at least for the IV, history 

has the stranded cable and a solid wire would be a builder or operator mod. 

Not a lot of issues here.  Most modifications that I am aware of have to do 

with reducing the effective strength of the spring.  Several ways to 

accomplish that.



Lowell



---

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Thu Jul 17, 2008 12:10 am Post subject: Throttle Cables

 	  Quote: 	
		   From: Lowell Fitt [lcfitt(at)sbcglobal.net]

 With the Kitfox 912 set-up, at least for the IV, history 

 has the stranded cable and a solid wire would be a builder or operator mod. 


	


We just got a warning to all Ikarus C42 aircraft pilots, here in Norway.

A pilot lost the control of his throttle when flying. The position it was left in was not enough to maintain altitude so the pilot decided to go for a cautious landing in a field. The landing went fine but, unfortunately there was a shallow ditch, invisble from the air and the nosegear collapsed. No injury; only damages to the nosegear and one main gear.



This was the preliminary report from the pilot, the technical inspection hasn't been done yet but all owners of such an aircaft are asked to check their throttle cable.



.. but isn't the 912 equipped with a spring that brings the carb to WOT when the cable fails? My Jabiru is.



Cheers,

Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200

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_________________
Kitfox 3 - Jabiru 2200

Lynn Matteson

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

Posted: Thu Jul 17, 2008 4:38 am Post subject: Throttle Cables

Same here, Michel....sprung to wide open throttle (WOT). As I recall  

working on a 914, that it was that way also.



Lynn Matteson

Kitfox IV Speedster

Jabiru 2200

Status: flying w/547+ hrs





On Jul 17, 2008, at 4:07 AM, Michel Verheughe wrote:

 	  Quote: 	
		  

 ... but isn't the 912 equipped with a spring that brings the carb  

 to WOT when the cable fails? My Jabiru is.



 Cheers,

 Michel Verheughe

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

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