Today's Message Index:
----------------------
1. 11:57 AM - For Sale ()
2. 12:26 PM - Choke Control (Bill Berle)
3. 03:57 PM - Re: Choke Control (Stuart Harner)
4. 06:55 PM - Tundra tires (Larry Cottrell)
5. 09:57 PM - Re: Choke Control (Richard Girard)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
2000 Kolb FireStar II $7500 obo. 503 DCDI, electric start, oil
injection, 600 hrs TT, IVO 2 blade prop,
BRS, Poly-Fibre covering, GRT EIS, Kuntzleman hotbox, heel brakes.
Always hangered Southern Calif.
Contact Lloyd McFarlane 714-388-4520
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Happy Tuesday Kolbers, I'm trying to hook up the throttle and choke cables for
my HKS installation.
Because I'm an "airplane guy" instead of an "ultralight guy" it's been rather frustrating,
to say the least. Hooking up one way "pull-only" controls that rely
on a return spring on the carburetor arm is counter-intuitive to me. There was
almost no friction in the entire throttle system, including the cable "splitter",
until I hooked up the throttle arm return spring. As soon as I hooked it
up the entire system had way way more resistance to pulling the cable. Seemed
like way too much resistance to movement.
Now I understand why the Kolb has a very tall throttle lever.
Finally I managed to get the throttle mostly done except for final adjustment.
Now the choke is becoming a difficult problem.
I moved the choke lever from behind the pilot's left shoulder (factory position)
to the right side of the cockpit next to the pilot's right thigh. This seemed
safer to me, because I can always see where the choke lever is, instead of forgetting
it because it was out of my sight behind my head. So I ran a cable and
sheath from the choke "splitter" down to the right side of the cockpit. I mounted
the OEM choke lever (a piece of twisted aluminum sheet metal) using an
Adel airframe clamp on one of the fuselage tubes.
The problem is that the choke lever doesn't exert enough force on the cable to
overcome the friction in the system when the (really strong) return springs are
hooked up on the carburetor. I don't feel good about using weaker springs, because
they may not allow the choke to spring back to the OFF position.
I believe that these cable friction problems are "built in" because of how many
bends and changes in direction that the throttle and choke cables go through
on a Kolb installation. But since there have been hundreds or thousands of Kolbs
flying for years with return spring type systems... I want to figure out whether
I am doing something wrong, or whether everybody else has the same problems
and complaints about their throttle and choke systems.
The cable "splitter" units are smooth, I took them apart and lubricated them.I
used new throttle cable and sheath for most of it. I used brand new brass elbow
fittings screwed in to the tops of the carburetors (Bing). I verified that the
throttle and choke controls worked smoothly and with little friction when I
disconnected the return springs.
Can anybody guess or predict if or what I'm doing wrong here?
Bill Berle
HKS Firestar
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Bill,
Possibly what you are experiencing is just normal friction plus return spring resistance.
Some thoughts:
The return spring for the choke needs to hold the choke open against airflow and
also should be able to supply enough force to pull a broken cable through the
cable housing. Suppose the cable broke at the lever end while it was pulled
all the way out, you would need enough spring to overcome whatever friction could
be introduced to the system if that should happen. In reality that is a very
remote possibility at best because normally you would shut the choke off while
still on the ground and are not likely to touch it again until the next startup.
Now, the throttle is a different matter. If something should break in the linkage
somewhere, what do you want the carburetor to do? Go full power as the default
or go to idle? The usual choice is go to idle. In most cases that is considered
the lesser of two evils. One would hope that proper pre-flight inspections
would prevent any such event from ever happening. But you must always consider
"what if".
So, how to tell how much resistance is too much. (remember, "resistance is futile").
Here is a little test. You can probably judge it by feel alone, but if you use
a small spring scale you can quantify it for your satisfaction.
1) Disconnect the cables at the carburetor and pull each control with the proper
spring installed. Note the force required.
2) With the cable still disconnected (but routed the way you have them) pull from
each direction and note the force required. I would think it should be the
same going both ways.
3) Connect the cables to the carburetor and pull again. Forces should be the sum
of those measured independently or just slightly more.
Now, if you think the test # 2 has too much friction, remove the cable and lay
it out straight and re-test. The difference will be what your routing added to
the mix. Usually the only time this is a factor is if you have lots of turns
or turns with too small of a radius.
All of this assumes you have not tightened the control levers too tight and introduced
a lot of friction there. For my Firefly, I played with different washer
thicknesses and tensions until I found the combination that introduced as little
friction as possible but still would hold the throttle against the return
spring. As things have worn a little it will creep down just a little at cruise.
Someday I will have to tighten it a little to stop the creeping.
I had to manufacture some cable ends for the control lever side of things as none were available for purchase when I needed them. You can check it out here: http://harnerfarm.net/serenity/engine.html
If I didn't explain this very well, let me know and I will try and re-word it.
Sometimes what is in my head doesn't translate to the keyboard very well.
Stuart
-----Original Message-----
From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Bill Berle
Sent: Tuesday, May 16, 2017 2:24 PM
Subject: Kolb-List: Choke Control
Happy Tuesday Kolbers, I'm trying to hook up the throttle and choke cables for
my HKS installation.
Because I'm an "airplane guy" instead of an "ultralight guy" it's been rather frustrating,
to say the least. Hooking up one way "pull-only" controls that rely
on a return spring on the carburetor arm is counter-intuitive to me. There was
almost no friction in the entire throttle system, including the cable "splitter",
until I hooked up the throttle arm return spring. As soon as I hooked it
up the entire system had way way more resistance to pulling the cable. Seemed
like way too much resistance to movement.
Now I understand why the Kolb has a very tall throttle lever.
Finally I managed to get the throttle mostly done except for final adjustment.
Now the choke is becoming a difficult problem.
I moved the choke lever from behind the pilot's left shoulder (factory position)
to the right side of the cockpit next to the pilot's right thigh. This seemed
safer to me, because I can always see where the choke lever is, instead of forgetting
it because it was out of my sight behind my head. So I ran a cable and
sheath from the choke "splitter" down to the right side of the cockpit. I mounted
the OEM choke lever (a piece of twisted aluminum sheet metal) using an
Adel airframe clamp on one of the fuselage tubes.
The problem is that the choke lever doesn't exert enough force on the cable to
overcome the friction in the system when the (really strong) return springs are
hooked up on the carburetor. I don't feel good about using weaker springs, because
they may not allow the choke to spring back to the OFF position.
I believe that these cable friction problems are "built in" because of how many
bends and changes in direction that the throttle and choke cables go through
on a Kolb installation. But since there have been hundreds or thousands of Kolbs
flying for years with return spring type systems... I want to figure out whether
I am doing something wrong, or whether everybody else has the same problems
and complaints about their throttle and choke systems.
The cable "splitter" units are smooth, I took them apart and lubricated them.I
used new throttle cable and sheath for most of it. I used brand new brass elbow
fittings screwed in to the tops of the carburetors (Bing). I verified that the
throttle and choke controls worked smoothly and with little friction when I
disconnected the return springs.
Can anybody guess or predict if or what I'm doing wrong here?
Bill Berle
HKS Firestar
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
http://highdesertflier.blogspot.com/
The link is to a page of my personal blog wherein I document the
problems relating to the purchase of Desser Tires, Aero Classic Smooth
Tundra tire for my Firestar. It covers how I balanced them in spite of
the fact that one of the tires required 14.7 ounces of weight to
balance. Perhaps some of you will have a better solution, if so I
would be interested to hear it.
I contacted Desser and thought for a while that they were going to
replace the tire. They were supposed to have contacted me by the end
of the day to tell me what they had decided. I have not heard anything
so I assume that they decided to shine me on.
I documented my process as well as I could, and as long as I can keep
the weights stuck to the rims I should be ok.
If any of you were considering these tires I suggest that you wade
through the page.
Larry
--
The older I get, the less tolerant I am of those who are intolerant of others.
If you forward this email, or any part of it, please remove my email
address before sending.
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Choke Control |
Bill, The Bing 64 carburetor has no choke. What it does have is a starting
carburetor that is jetted richer than the 64. It only works below about
3,000 RPM so leaving it open won't be noticed until you pull power for
approach and notice an unusually high idle.
One thing that has always bothered me about the HKS installation of the 64
is that it is like a motorcycle, if the cable breaks the carburetor goes to
idle. I'd love to change it out to the Rotax system. Like a regular
airplane engine if the cable breaks the engine goes to full throttle so
only a very light spring is needed. The cable pushes the throttle open and
pulls it closed. McFarlane Aviation Products;
http://www.mcfarlaneaviation.com/ has a dual cable throttle for the 912
that requires no mixer and uses 1 X 19 cable that easily handles the
push/pull requirements.
The Rotax 912 IPC has a drawing of the way their throttle works.
Rick Girard
On Tue, May 16, 2017 at 5:56 PM, Stuart Harner <stuart@harnerfarm.net>
wrote:
>
> Bill,
>
> Possibly what you are experiencing is just normal friction plus return
> spring resistance.
>
> Some thoughts:
>
> The return spring for the choke needs to hold the choke open against
> airflow and also should be able to supply enough force to pull a broken
> cable through the cable housing. Suppose the cable broke at the lever end
> while it was pulled all the way out, you would need enough spring to
> overcome whatever friction could be introduced to the system if that shou
ld
> happen. In reality that is a very remote possibility at best because
> normally you would shut the choke off while still on the ground and are n
ot
> likely to touch it again until the next startup.
>
> Now, the throttle is a different matter. If something should break in the
> linkage somewhere, what do you want the carburetor to do? Go full power a
s
> the default or go to idle? The usual choice is go to idle. In most cases
> that is considered the lesser of two evils. One would hope that proper
> pre-flight inspections would prevent any such event from ever happening.
> But you must always consider "what if".
>
> So, how to tell how much resistance is too much. (remember, "resistance i
s
> futile").
>
> Here is a little test. You can probably judge it by feel alone, but if yo
u
> use a small spring scale you can quantify it for your satisfaction.
>
> 1) Disconnect the cables at the carburetor and pull each control with the
> proper spring installed. Note the force required.
> 2) With the cable still disconnected (but routed the way you have them)
> pull from each direction and note the force required. I would think it
> should be the same going both ways.
> 3) Connect the cables to the carburetor and pull again. Forces should be
> the sum of those measured independently or just slightly more.
>
> Now, if you think the test # 2 has too much friction, remove the cable an
d
> lay it out straight and re-test. The difference will be what your routing
> added to the mix. Usually the only time this is a factor is if you have
> lots of turns or turns with too small of a radius.
>
> All of this assumes you have not tightened the control levers too tight
> and introduced a lot of friction there. For my Firefly, I played with
> different washer thicknesses and tensions until I found the combination
> that introduced as little friction as possible but still would hold the
> throttle against the return spring. As things have worn a little it will
> creep down just a little at cruise. Someday I will have to tighten it a
> little to stop the creeping.
>
> I had to manufacture some cable ends for the control lever side of things
> as none were available for purchase when I needed them. You can check it
> out here: http://harnerfarm.net/serenity/engine.html
>
> If I didn't explain this very well, let me know and I will try and re-wor
d
> it. Sometimes what is in my head doesn't translate to the keyboard very
> well.
>
> Stuart
>
>
> -----Original Message-----
> From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-
> server@matronics.com] On Behalf Of Bill Berle
> Sent: Tuesday, May 16, 2017 2:24 PM
> To: kolb-list@matronics.com
> Subject: Kolb-List: Choke Control
>
>
> Happy Tuesday Kolbers, I'm trying to hook up the throttle and choke cable
s
> for my HKS installation.
>
> Because I'm an "airplane guy" instead of an "ultralight guy" it's been
> rather frustrating, to say the least. Hooking up one way "pull-only"
> controls that rely on a return spring on the carburetor arm is
> counter-intuitive to me. There was almost no friction in the entire
> throttle system, including the cable "splitter", until I hooked up the
> throttle arm return spring. As soon as I hooked it up the entire system h
ad
> way way more resistance to pulling the cable. Seemed like way too much
> resistance to movement.
>
> Now I understand why the Kolb has a very tall throttle lever.
>
> Finally I managed to get the throttle mostly done except for final
> adjustment. Now the choke is becoming a difficult problem.
>
> I moved the choke lever from behind the pilot's left shoulder (factory
> position) to the right side of the cockpit next to the pilot's right thig
h.
> This seemed safer to me, because I can always see where the choke lever i
s,
> instead of forgetting it because it was out of my sight behind my head. S
o
> I ran a cable and sheath from the choke "splitter" down to the right side
> of the cockpit. I mounted the OEM choke lever (a piece of twisted aluminu
m
> sheet metal) using an Adel airframe clamp on one of the fuselage tubes.
>
> The problem is that the choke lever doesn't exert enough force on the
> cable to overcome the friction in the system when the (really strong)
> return springs are hooked up on the carburetor. I don't feel good about
> using weaker springs, because they may not allow the choke to spring back
> to the OFF position.
>
> I believe that these cable friction problems are "built in" because of ho
w
> many bends and changes in direction that the throttle and choke cables go
> through on a Kolb installation. But since there have been hundreds or
> thousands of Kolbs flying for years with return spring type systems... I
> want to figure out whether I am doing something wrong, or whether everybo
dy
> else has the same problems and complaints about their throttle and choke
> systems.
>
> The cable "splitter" units are smooth, I took them apart and lubricated
> them.I used new throttle cable and sheath for most of it. I used brand ne
w
> brass elbow fittings screwed in to the tops of the carburetors (Bing). I
> verified that the throttle and choke controls worked smoothly and with
> little friction when I disconnected the return springs.
>
> Can anybody guess or predict if or what I'm doing wrong here?
>
>
> Bill Berle
> HKS Firestar
>
>
===========
===========
===========
===========
===========
>
>
--
=9CBlessed are the cracked, for they shall let in the light.=9D
Groucho Marx
<http://www.goodreads.com/author/show/43244.Groucho_Marx>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|