Today's Message Index:
----------------------
1. 12:04 AM - Re: Runaway trim (Fiveonepw@aol.com)
2. 07:01 AM - Re: Runaway trim (Valovich, Paul)
3. 08:02 AM - Runaway trim (Fergus Kyle)
4. 08:35 AM - Re: Isolated DC-DC Electronics design pointers (Ron Quillin)
5. 08:44 AM - Re: Runaway trim (Ron Quillin)
6. 09:23 AM - Re: First Start of my rotary (Hinde, Frank George (Corvallis))
7. 09:23 AM - Re: Runaway trim (john@ballofshame.com)
8. 11:00 AM - Re: Runaway trim (Buckaroo Banzai)
9. 11:07 AM - Re: First Start of my rotary (Ernest Christley)
10. 11:38 AM - Re: Runaway trim (Robert L. Nuckolls, III)
11. 01:47 PM - Re: Runaway trim (Kevin Horton)
12. 01:47 PM - Re: Runaway trim (Kevin Horton)
13. 01:52 PM - Re: Runaway trim (Doug Windhorn)
14. 02:36 PM - Re: Runaway trim (Kevin Horton)
15. 03:52 PM - Re: Isolated DC-DC Electronics design pointers (Ralph Hoover)
16. 05:17 PM - Re: Runaway trim (Glen Matejcek)
17. 06:24 PM - JJN 80 Amp "Boltable" Fuse Source (Michel Creek)
18. 06:43 PM - Re: JJN 80 Amp "Boltable" Fuse Source (Michael T. Ice)
19. 07:02 PM - Re: JJN 80 Amp "Boltable" Fuse Source (Michel Creek)
20. 07:15 PM - Re: Runaway trim (Robert L. Nuckolls, III)
21. 08:04 PM - Re: JJN 80 Amp "Boltable" Fuse Source (Robert L. Nuckolls, III)
22. 08:52 PM - Re: JJN 80 Amp "Boltable" Fuse Source (Joemotis@aol.com)
23. 08:58 PM - Re: JJN 80 Amp "Boltable" Fuse Source (Joemotis@aol.com)
24. 09:11 PM - Annunciator HELP! (Fiveonepw@aol.com)
Message 1
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Subject: | Re: Runaway trim |
In a message dated 6/6/2007 11:03:59 PM Central Daylight Time,
DAVELEIKAM@wi.rr.com writes:
Should we or has anyone installed a trim power disconnect of some sort?
>>>
Already done- it's called the "Master Switch". First indication of a trim
runaway and this puppy gets nailed. Trim is on Main Bus, so it dies as fast as
you can react. E-bus for remainder of flight.
Mark Phillips - Z-11 RV-6A
_http://websites.expercraft.com/n51pw/_ (http://websites.expercraft.com/
n51pw/) (http://websites.expercraft.com/n51pw)
************************************** See what's free at http://www.aol.com.
Message 2
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Subject: | Re: Runaway trim |
I intend to have both roll trim and pitch trim disconnect switches on
the side panel.
However, more importantly, during the test phase I will fly with full
nose up / nose down trim.
Paul Valovich
RV-8A N192NM (Reserved)
Message 3
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A circuit breaker is not an emergency switch. Looking for it on the
panel is not a good idea when the aircraft may be going out of control.
A critical question to ask when searching for a kit/project is:
'Can this design be flown when at the extremes of trim range?'
If not, it should be shunned. That is a criterion most required of
any design with relatively limited speed range.
If so, then time is available to plan for a safe landing under the
circumstances. At least there is little need to panic - if in automatic
flight, disconnect and handfly. If not, the fastest reaction is your
(already-) attached hand.
Engine failure on take-off and runaway trim are perhaps the two most
demanding failures. On every takeoff one should be spring-loaded to expect
the engine to quit. The exhilaration of a successful takeoff is the
knowledge the engine didn`t quit!
If runaway trim is too rapid to react to, then the trim motor needs
slowing.......
Happy landings
Ferg
Europa A064
Message 4
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Subject: | Re: Isolated DC-DC Electronics design pointers |
At 20:19 6/6/2007, you wrote:
> I have attached a schematic and photo's of the 9VDC ANR supply I
> have built for my RV7A (Headsets Inc ANR conversion) I have tested
> the supply for basic DC voltage. I
Shouldn't converter pin 7 in your schematic be VOUT- ?
Likely just an oversight/typo, but could confuse years later.
Ron Q.
Message 5
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Subject: | Re: Runaway trim |
At 22:00 6/6/2007, you wrote:
>Should we or has anyone installed a trim power disconnect of some
>sort? <snip> After Attending Bob Nuckolls seminar and hearing his
>reasons for not installing circuit breakers which I generally agree
>with, would this be a reason for a pullable breaker on this
>circuit? What do you guys and gals think?
Many certified A/P and electric trim systems have multiple means to
effect an emergency disconnect.
A Century Flight Systems system with which I am quite familiar has three:
1) yoke mounted momentary disconnect/override
2) panel mounted on/off toggle switch; one each for A/P and trim
3) panel mounted pullable circuit breakers; one each for A/P and trim
This is in addition to the mechanical trim control that can override
the clutch of the system.
Overkill, perhaps. But like I mentioned, it's a certified system in
a certified aircraft.
It does, however, provide redundancy; and points of failure...
Ron Q.
Message 6
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Subject: | First Start of my rotary |
Didn't say they don't work but the debate over how fast they go VS. how
much fuel burn has never been proven to my knowledge...I.e water cooled
engines have an inherrent disadvantage in that they have more drag to
overcome. That can be done with careful ducting but it's a hard thing to
do with the engine so close to the front.
Has it been done on an RV?..I dunno,...Does it matter?...I.e if it costs
1 gallon per hour more in a Rotary coversion but the conversion is half
price compared to a Lyc it may still be a good deal.
Frank
Do not archive
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bob
White
Sent: Wednesday, June 06, 2007 3:46 PM
Subject: Re: AeroElectric-List: First Start of my rotary
Hi Frank,
Better not tell all those guys flying RV's with rotary engines.
Bob W.
On Wed, 6 Jun 2007 20:58:14 -0000
"Hinde, Frank George (Corvallis)" <frank.hinde@hp.com> wrote:
> Indeed, although the web page is a little out of date as Experimental
> Lyclones are now way cheaper than the 34K listed...More like 21 to 24k
> for a brand new fuel injected IO360.
>
> The rotary is a fascinating conversion however (not good for a tractor
> airplane due to the difficulty in getting long ducts to deal with the
> cooling drag, but much more amenable to a pusher design I think.
>
> Good job
>
> Frank
>
> ________________________________
>
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> longg@pjm.com
> Sent: Wednesday, June 06, 2007 1:15 PM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: First Start of my rotary
>
>
> Congratulations Chris,
> A freshly minted non-smoking wiring system and a smooth running
> rotary are proud milestones.
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> Christopher Barber
> Sent: Wednesday, May 30, 2007 11:40 PM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: First Start of my rotary
>
>
> Just a quick note to announce the first starts of my 13b rotary
> engine in my Velocity SE wired with Bob's Z-14 diagrams. Thanks for
> the great info in the book and on this list. It provides a great deal
> of piece of mind. If you are interested in more details check out my
> posts or those of my buddy David Staten who is helping me in the
> build, on www.canardaviation.com or the flyrotary email list. Thanks
Bob.
>
> All the best,
>
> Chris
> www.LoneStarVelocity.com
> Houston, Texas
>
>
>
> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www
> .m atronics.com/Navigator?AeroElectric-List
> href="http://forums.matronics.com">http://forums.matronics.com
>
>
>
>
>
>
>
>
--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://www.roblinphoto.com/shop/
Message 7
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Subject: | Re: Runaway trim |
What anyone should take away from ANY discussion of fuses, switches and
breakers is:
"Use the right tool for the right job."
It seems perfectly reasonable to me to use a switchable breaker like a
Klixon (my favorite) or a P&B for things which you may want to switch off
for regular maintenance or emergencies. Alternator field, electric trim
and electric flaps seem like a very good use for a breaker.
Another thing to consider which I haven't seen anyone do is a warning tone
whenever the trim or flaps are energized. Low pitch for trim...hi for
flaps...something like that. You could also install a blinky light right
next to the breaker that controls the piece of equipment in question.
This would be trivial as you'd just take power right at the breaker. Any
time current flowed, the light would go on. So warning tone goes off,
"Hey, I'm not moving the trim!!", look over and yank the breaker with the
blinky light. Bad idea? Maybe. It's not a suggestion...just food for
thought.
While it's nice to think that most of us would catch a runaway trim or
flap motor, and then just do the right thing because we're all trained and
proficient, the reality is that the pilot is not only the most flexible
and capable part of the system but also often the weak link esp. when
things go wrong. Systems should be balanced to both be efficient AND give
the pilot every advantage.
my $.02
-John
www.ballofshame.com
Message 8
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Subject: | Re: Runaway trim |
Cessna used to use a split switch for electric trim (they might still but I don't
have any recent experience with Cessnas) so that two failures would have to
occur to get runaway trim. Of course, you should also make sure the wiring from
each of the switches is isolated from the other and the trim power relays
are isolated from each other (physical separation or barriers) to prevent a short
across both switches or relays.
Greg
Dave Leikam <DAVELEIKAM@wi.rr.com> wrote: A few days ago a Citation jet carrying
a crew of two and 4 medical personnel including organ transplant doctors,
went down in Lake Michigan just off shore from Milwaukee, WI shortly after
takeoff. The pilot declared an emergency due to severe control problems and
was cleared to return to MKE. No survivors. First my condolences to the
families and friends. Next, preliminary reports are that the crash may have
been due to "Runaway trim." Our RV-10s have electric trim. Should we or has
anyone installed a trim power disconnect of some sort? I realize that the
forces to overcome full trim on the 10 are not as great as a Citation, but would
this be prudent? After Attending Bob Nuckolls seminar and hearing his reasons
for not installing circuit breakers which I generally agree with, would
this be a reason for a pullable breaker on this circuit? What do you guys and
gals think? Mr. Nuckolls, how about your
thoughts?
Dave Leikam
40496 RV-10
QB Wings
---------------------------------
Moody friends. Drama queens. Your life? Nope! - their life, your story.
Play Sims Stories at Yahoo! Games.
Message 9
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Subject: | Re: First Start of my rotary |
Hinde, Frank George (Corvallis) wrote:
>
> Didn't say they don't work but the debate over how fast they go VS. how
> much fuel burn has never been proven to my knowledge...I.e water cooled
> engines have an inherrent disadvantage in that they have more drag to
> overcome. That can be done with careful ducting but it's a hard thing to
> do with the engine so close to the front.
>
>
Water cooled engines have an inherent advantage in that they don't have
to have the radiator up front just because that is where the engine is.
Here's a picture of my oil cooler arrangement. The radiator is on the
other side. Tractor configuration. Picture is from the front of the
airplane. The black triangle up front is part of the firewall.
http://www.ernest.isa-geek.org/Delta/Pictures/OilCoolerDuctFront.jpg
Advantages: Better weight and balance configuration. NACA studies
indicate that my inlet and outlet placement will provide the least drag
of any cooling arrangement except for jets or rockets.
The fuel burn question will never be answered, IMHO, regardless of how
much data you provide showing the rotary gobbles gas if you try to fly
it like a Lycoming, but the difference falls into the noise when you fly
it like a rotary. The BSFC goes through the roof when the mixture is
configured for best power (the only regime anyone seems to care about on
a dyno), but stays quite reasonable when properly leaned for a power
regime that keeps the plane under Vne. To complicated for most, I
guess. I give up. The doubters win. I'll just tell people that I have
secret tanks concealed with a cloaking device and levitated with my
anti-gravity pixie-dust so that the fuel it contains doesn't add to the
airplane's gross weight. The extra fuel is delivered at night by
secret-ops Federal Marshalls under the direct supervision of the CEO of
Exxon, because I know of some dirty secrets on Dick Cheney's
good-ol'-boy network. That should be a much more convincing story of
why all the rotary powered aircraft seem to have the same range as their
Lycoming powered brethren.
To bring this back on topic for this discussion list, the rotary has
another advantage in that the output shaft is turning at 6000RPM or so
at cruise. Just about right for a direct-drive generator. With a PM
rotor mounted directly to the shaft, there's no need for belts or
gears. No weight needed for a heavy case or robust and heavy mounting
brackets. In a tractor configuration, it will be constantly impacted by
fresh cooling air.
Message 10
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Subject: | Re: Runaway trim |
At 09:22 AM 6/7/2007 -0700, you wrote:
>
>What anyone should take away from ANY discussion of fuses, switches and
>breakers is:
>
>"Use the right tool for the right job."
>
>It seems perfectly reasonable to me to use a switchable breaker like a
>Klixon (my favorite) or a P&B for things which you may want to switch off
>for regular maintenance or emergencies. Alternator field, electric trim
>and electric flaps seem like a very good use for a breaker.
>
>Another thing to consider which I haven't seen anyone do is a warning tone
>whenever the trim or flaps are energized. Low pitch for trim...hi for
>flaps...something like that. You could also install a blinky light right
>next to the breaker that controls the piece of equipment in question.
>This would be trivial as you'd just take power right at the breaker. Any
>time current flowed, the light would go on. So warning tone goes off,
>"Hey, I'm not moving the trim!!", look over and yank the breaker with the
>blinky light. Bad idea? Maybe. It's not a suggestion...just food for
>thought.
>
>While it's nice to think that most of us would catch a runaway trim or
>flap motor, and then just do the right thing because we're all trained and
>proficient, the reality is that the pilot is not only the most flexible
>and capable part of the system but also often the weak link esp. when
>things go wrong. Systems should be balanced to both be efficient AND give
>the pilot every advantage.
There are many, Many, MANY approaches to building firewalls against
the undesirable. The task is first to see if a firewall is even
necessary. Finally, the elegant solution calls for a minimum parts
count solution with low cost of ownership and minimizing probability
that "Plan-B" for pitch trim failure is not more likely to be
a maintenance problem than the pitch trim system being monitored/
protected. See:
http://www.aeroelectric.com/articles/Trim_System_Failures.pdf
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 11
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Subject: | Re: Runaway trim |
On 7 Jun 2007, at 00:00, Dave Leikam wrote:
> A few days ago a Citation jet carrying a crew of two and 4 medical
> personnel including organ transplant doctors, went down in Lake
> Michigan just off shore from Milwaukee, WI shortly after takeoff.
> The pilot declared an emergency due to severe control problems and
> was cleared to return to MKE. No survivors. First my condolences
> to the families and friends. Next, preliminary reports are that
> the crash may have been due to "Runaway trim." Our RV-10s have
> electric trim. Should we or has anyone installed a trim power
> disconnect of some sort? I realize that the forces to overcome
> full trim on the 10 are not as great as a Citation, but would this
> be prudent? After Attending Bob Nuckolls seminar and hearing his
> reasons for not installing circuit breakers which I generally agree
> with, would this be a reason for a pullable breaker on this
> circuit? What do you guys and gals think? Mr. Nuckolls, how about
> your thoughts?
>
If you have electric trim, you should set do flight testing to
confirm that you can handle a full travel trim runaway at high
speed. You can minimize the stick forces by setting the trim travel
to the minimum required to trim off forces in the two extreme cases
(VNE at aft CG and approach speed at forward CG).
If a trim runaway happens, you can minimize the amount of mistrim by
having a quick way to remove power from the trim, but it needs to be
something that you can find and actuate very quickly. I've got a big
red button on my stick grip. Pushing and holding that button removes
power from the trim and wing leveler. I then would turn off the
power switch for trim or wing leveler, and release the big red button.
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 12
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Subject: | Re: Runaway trim |
On 7 Jun 2007, at 08:59, Valovich, Paul wrote:
> However, more importantly, during the test phase I will fly with
> full nose up / nose down trim.
The worst case failures to look at for this test would likely be:
CG at the aft limit, VNE, full nose up trim runway, and
CG at the forward limit, flaps down, approach speed, full nose down
trim runaway.
Areas of interest to investigate during the tests:
Starting from an in-trim condition, and holding the trim switch, but
letting the aircraft respond naturally - how long do you have to
react before a dangerous condition results? Are you comfortable that
you would always react that quickly? If not, maybe the trim rate
should be slowed down. As a reference, for transport category
aircraft, it is expected that the crew could delay their reaction for
up to three seconds in cruise without a dangerous condition being
reached. On final approach, it is assumed that the crew will react
within one second.
What are the stick forces required once you react to the failure by
applying a stick force to counter the aircraft pitching motion? Are
you comfortable that you could hold this high a stick force for the
time required to get the aircraft on the ground? Could you fly a
safe landing holding this much stick force?
How should you fly the approach following this failure (which flap
angle and approach speed)? If the runway is nose down, the stick
forces might be lighter if you do an approach with the flaps up, and
a bit higher speed than normal.
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 13
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Subject: | Re: Runaway trim |
Not about to become in the probability or need of trim system interrupts,
but since it is of some concern, the following approach might be of interest
to some (those not tied to the dual stick coolie hat switches). This is
from another web list, and is a modification I will make to my system on the
next wiring go-around.
First, use only one trim input point such as on the panel, one on each stick
aggravates the possibility of unwanted trim travel, either accidentally, or
through cross-inputting. That location of the switches would be available
to both pilot/copilot in a side by side seating. This may eliminate the
need for relays (except for switch wear).
Use two (on)-off-(on) rocker switches, installed side by side. The 1st
switch is the power control switch. The 2nd switch is the servo control
switch. Both must be activated simultaneously to move the servo. Wire the
outputs [(on)] of the first switch to together and input to the 2nd switch
[off] and any relays or other components in the trim system needing power.
Unless the power switch is moved to either (on) position, there is no power
to the trim system and it should not go anywhere; no need to get into a
reactive situation, or have a pullable breaker.
Doug Windhorn
----- Original Message -----
From: <john@ballofshame.com>
Sent: Thursday, 07 June, 2007 9:22
Subject: Re: AeroElectric-List: Runaway trim
>
> What anyone should take away from ANY discussion of fuses, switches and
> breakers is:
>
> "Use the right tool for the right job."
>
> It seems perfectly reasonable to me to use a switchable breaker like a
> Klixon (my favorite) or a P&B for things which you may want to switch off
> for regular maintenance or emergencies. Alternator field, electric trim
> and electric flaps seem like a very good use for a breaker.
>
> Another thing to consider which I haven't seen anyone do is a warning tone
> whenever the trim or flaps are energized. Low pitch for trim...hi for
> flaps...something like that. You could also install a blinky light right
> next to the breaker that controls the piece of equipment in question.
> This would be trivial as you'd just take power right at the breaker. Any
> time current flowed, the light would go on. So warning tone goes off,
> "Hey, I'm not moving the trim!!", look over and yank the breaker with the
> blinky light. Bad idea? Maybe. It's not a suggestion...just food for
> thought.
>
> While it's nice to think that most of us would catch a runaway trim or
> flap motor, and then just do the right thing because we're all trained and
> proficient, the reality is that the pilot is not only the most flexible
> and capable part of the system but also often the weak link esp. when
> things go wrong. Systems should be balanced to both be efficient AND give
> the pilot every advantage.
>
> my $.02
>
> -John
> www.ballofshame.com
>
>
>
Message 14
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Subject: | Re: Runaway trim |
On 7 Jun 2007, at 15:47, Doug Windhorn wrote:
> Use two (on)-off-(on) rocker switches, installed side by side. The
> 1st switch is the power control switch. The 2nd switch is the
> servo control switch. Both must be activated simultaneously to move
> the servo. Wire the outputs [(on)] of the first switch to together
> and input to the 2nd switch [off] and any relays or other
> components in the trim system needing power. Unless the power
> switch is moved to either (on) position, there is no power to the
> trim system and it should not go anywhere; no need to get into a
> reactive situation, or have a pullable breaker.
>
If you go down this road, you should add a first flight of the day
ground test to confirm that the power switch has not failed in the
hot position. This would be a dormant failure, which would defeat
the protection provided by this design, and would only be detected by
a specific test.
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 15
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Subject: | Re: Isolated DC-DC Electronics design pointers |
Ron,
Good catch. Thanks!
Here is a revised PDF.
--
Ralph C. Hoover
RV7A
hooverra at verizon dot net
Message 16
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Subject: | Re: Runaway trim |
Hi Dave-
RE: After Attending Bob Nuckolls
seminar and hearing his reasons for not installing circuit breakers
which I generally agree with, would this be a reason for a pullable
breaker on this circuit? What do you guys and gals think? Mr.
Nuckolls, how about your thoughts?
For my part, on my -8, which is of course a tandem, I do have a way to defeat the
trim. My original concern was to be able to render the aft trim inop should
someone back there do something innapropriate. One thing led to another, and
what I have now is a progressive switch wired up to manage the trim system.
The way it's configured, in the up position the grounds from both MAC stick grips
are connected to the ground bus and the whole sys is operative. In the central
position, the fwd stick still grounds, but the aft is isolated. In the
down position, only the fwd PTT still grounds. This way I can protect against
errors in the back as well as a runaway with the flick of one switch.
FWIW-
gm
Glen Matejcek
Message 17
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Subject: | JJN 80 Amp "Boltable" Fuse Source |
Does anyone know a good source for a JJN/JJS style 80 amp "boltable" fuse?
I'm wiring a 60 amp alternator per Z-22, but I can't seem to locate the
right fuse to wire in-line between the alternator and starter leads. I've
checked B&C and AC Spruce.
Thanks,
Mike C.
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Subject: | Re: JJN 80 Amp "Boltable" Fuse Source |
Michel,
www.marineengineparts.com/shopsite_sc/store/html/page223.html
Is this the type of fuse you are looking for?
Mike
----- Original Message -----
From: "Michel Creek" <mwcreek@frontiernet.net>
Sent: Thursday, June 07, 2007 5:21 PM
Subject: AeroElectric-List: JJN 80 Amp "Boltable" Fuse Source
> <mwcreek@frontiernet.net>
>
> Does anyone know a good source for a JJN/JJS style 80 amp "boltable" fuse?
> I'm wiring a 60 amp alternator per Z-22, but I can't seem to locate the
> right fuse to wire in-line between the alternator and starter leads. I've
> checked B&C and AC Spruce.
>
> Thanks,
> Mike C.
>
>
>
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Subject: | JJN 80 Amp "Boltable" Fuse Source |
Thanks Mike. Those would work if they can be used in-line with a 4 awg
cable in about an 8-inch run. There isn't anyplace to mount an ANL type
base so the fuse must be strong enough in tension to survive in the high
vibration environment between the alternator and starter.
Searching the archives, Bob made reference to a JJN/JJS style "boltable"
fuse for that application.
Do Not Archive
------------------------------------------------------------------------
Michel,
www.marineengineparts.com/shopsite_sc/store/html/page223.html
Is this the type of fuse you are looking for?
Mike
>
> Does anyone know a good source for a JJN/JJS style 80 amp "boltable" fuse?
> I'm wiring a 60 amp alternator per Z-22, but I can't seem to locate the
> right fuse to wire in-line between the alternator and starter leads. I've
> checked B&C and AC Spruce.
>
> Thanks,
> Mike C.
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Subject: | Re: Runaway trim |
Thanks to the welcome attention of a few readers on the List, I've
updated the article below to fix some wording . . . and
modified the schematic to make installation and operation easier
and more logical. Interested parties can get revision A at:
http://www.aeroelectric.com/articles/Trim_System_Failures.pdf
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
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Subject: | Re: JJN 80 Amp "Boltable" Fuse Source |
At 06:21 PM 6/7/2007 -0700, you wrote:
><mwcreek@frontiernet.net>
>
>Does anyone know a good source for a JJN/JJS style 80 amp "boltable" fuse?
>I'm wiring a 60 amp alternator per Z-22, but I can't seem to locate the
>right fuse to wire in-line between the alternator and starter leads. I've
>checked B&C and AC Spruce.
We discontinued that fuse when it proved less robust
mechanically than we would have liked. The recommended
replacement is the ANL series current limiters. Better
yet, consider the Littlefuse MEGA series fuses. See:
https://www.vtewarehouse.com/content/electromech/fuse/html/mega/megafuse.php
These are smaller and less expensive than the ANL devices.
Another option is the MAXI fuse which is also available with
an in-line holder at:
https://www.vtewarehouse.com/content/electromech/fuse/html/maxi/maxifuse.php
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
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Subject: | Re: JJN 80 Amp "Boltable" Fuse Source |
Bob, as a long time lurker and a former 68F20/68F30 I would like to thank
you for the personal knowledge you share so unselfishly.
The knowledge base that you have earned and so generously share is
immeasurable in it's contribution to the advancement of Aviation. JJN/JJS indeed.
Joe Motis
I.B.E.W. Local 11 Special Skills Electrician
601 XL
Do not archive
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Subject: | Re: JJN 80 Amp "Boltable" Fuse Source |
And it's=its when you proofread after the fact...
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Subject: | Annunciator HELP! |
This post is for the techno-weenies- all others delete NOW!
Goal: Illuminate an annunciator light when TruTrak servos are OFF using NKK
LB series illuminated pushbutton:
_http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=360&M=LB25RKW01-5C
-JC-RO_
(http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=360&M=LB25RKW01-5C-JC-RO)
This device is a DPDT PB with LED lamp, built-in resistor for the LED.
(Reason for using PB instead of simple lamp is provide built-in PTT function with
N.O. contacts. LED has its own +&- contacts on back of switch)
Consultation with TruTrak reveals that the torque line (pin6) to either servo
can be used to sense when power is applied to the servo, thereby providing
the necessary input. They sent a drawing showing a 10K resistor tied to this
pin gating on a darlington transistor to provide the switch (ground path) for a
lamp. Good, but I need the light OFF when power is on this pin. Please don't
ask why, this is what I want to happen.
I begged the list for guidance some time ago and Bob very generously supplied
sketches (THANKS!) for how to achieve this using a IRF510 MOSFET to either
(1) turn the lamp ON as TruTrak indicated, or (2) turn the lamp OFF by
connecting the MOSFET between a 470 ohm resistor supplying the LED and ground,
which I
understand would essentially remove voltage from the LED by shorting its
supply voltage to ground. With 13 volts supplied, this would be about 30mA through
the MOSFET when it is gated on, probably not resulting in a new-clee-ur
event. Problem is, I assume Bob is referring to the resistor normally used to
control LED current and since in the LB series switches this resistor is built
into the LED, connecting the MOSFET to the LED supply voltage would essentially
result in a dead short (minus MOSFET internal resistance) to ground. I'd
surmise Mr. MOSFET would melt?
Unless there is a more elegant solution, I suppose I could use the MOSFET to
ground a relay coil and use NC contacts to operate the LED, which in my
electronically-challenged understanding of this would get the job done. But even
after hours of googling to understand these MOSFET monsters these questions
remain:
What are the connections to this beast? "Gate" I understand- signal from
servo to gate on MOSFET. But what the heck are the "Source" (pin opposite gate)
and "Drain" (center pin)? I'm supposing "source" in this case would be
connection to the relay coil and "drain" is ground. Correct? One place I looked
(WebEE?) indicates the mounting flange for the MOSFET (TO-220 pkg) is common to
"drain" so that makes sense if the thing is mounted to the airframe. But
another source said to insulate this from ground. (?) Another speaks of monster
heatsinks, but I seriously doubt the coil current (75mA) of the relay of choice
(Omron LY2F) would make the MOSFET break a sweat...
If you managed to hang on this far, I'd sure appreciate some guidance- and if
y'all got a better mousetrap, I'm willing to stick my neck out!
Thanks and let's spare the archives with a do not archive thingie-
Mark (I grok batteries....maybe) Phillips
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