Today's Message Index:
----------------------
1. 12:29 AM - Insulator in durable gas tight compression (Jan de Jong)
2. 07:24 AM - Re: Insulator in durable gas tight compression (Robert L. Nuckolls, III)
3. 07:34 AM - Re: Insulator in durable gas tight compression (user9253)
4. 09:50 AM - Re: Insulator in durable gas tight compression (Dick Tasker)
5. 10:23 AM - Re: Landing gear electric actuator circuit (user9253)
6. 12:36 PM - Re: Insulator in durable gas tight compression (Jan de Jong)
7. 02:41 PM - Re: Insulator in durable gas tight compression (Jan de Jong)
8. 02:58 PM - Re: Insulator in durable gas tight compression (user9253)
9. 03:42 PM - Re: Re: Insulator in durable gas tight compression (Jan de Jong)
10. 05:20 PM - Re: Re: Landing gear electric actuator circuit (GTH)
11. 06:26 PM - Re: Re: Landing gear electric actuator circuit (C&K)
12. 06:42 PM - Re: Re: Landing gear electric actuator circuit (Kelly McMullen)
13. 08:14 PM - Re: Re: Landing gear electric actuator circuit (A R Goldman)
Message 1
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| Subject: | Insulator in durable gas tight compression |
I have a simple question.
Is there any example in acceptable practices where an insulating layer
(some laminate?) is part of the stack of metal layers that is compressed
to ensure a durable gas tight low resistance electrical connection
between the metal layers?
If there is such that would be great. If such can be categorically
denied that would be great too.
Thanks.
Jan de Jong
Message 2
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| Subject: | Re: Insulator in durable gas tight compression |
At 02:28 AM 3/4/2019, you wrote:
>Is there any example in acceptable practices where
>an insulating layer (some laminate?) is part of the
>stack of metal layers that is compressed to ensure
>a durable gas tight low resistance electrical
>connection between the metal layers?
Not aware of a joining technology
that uses any form of insulation to
augment integrity of the finished
joint. Gas-tight implies metal-to-
metal free of voids. Insulation
or any other material outside the
joint might be useful for protecting
the edges of the joint . . . like
solder over the 'western union'
splice or heat-shrink over
any other form of joining.
There are dozens of insulation-
displacement technologies wherein the
conductors push the insulation aside
during application . . . but it's
not clear that insulation surrounding
the finished joint is an integral
component of the design's service
life.
Bob . . .
Message 3
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| Subject: | Re: Insulator in durable gas tight compression |
Some switches are made with a layer of plastic included in the compressed electrical
connection.
They are prone to fail. How about mica?
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=487910#487910
Message 4
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| Subject: | Re: Insulator in durable gas tight compression |
I believe you are asking is it okay to use some sort of laminate in the stack-up
of layers wherein the goal is to have something to mount the connection to and
insulate it from your airplane sheet
metal and that will not affect the "gas-tightness" of the connection.
If that is the question, I believe that the answer would be that there are very
few materials that would allow that. Ceramic would work, but that is hared to
work with. Any plastic type material
probably is too soft to not allow some relaxation over time of the joint.
The way to do what I think you want is to connect the bolt (or whatever is part
of the whole assembly) to the laminate with a nut and then put the ring-lug (or
whatever needs to be connected) onto the
bolt and then use another nut to make the connection gas tight. Or if you are just
using the laminate to hold the joint in place, place the two lugs that need
to be connected over the first nut and
then use the final to make it gas tight.
If I have misinterpreted your goal, then just ignore this comment.
Dick Tasker
Jan de Jong wrote:
>
> I have a simple question.
> Is there any example in acceptable practices where an insulating layer (some
laminate?) is part of the stack of metal layers that is compressed to ensure a
durable gas tight low resistance
> electrical connection between the metal layers?
> If there is such that would be great. If such can be categorically denied that
would be great too.
> Thanks.
> Jan de Jong
>
>
Message 5
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| Subject: | Re: Landing gear electric actuator circuit |
Would this propeller current limiter be suitable for shutting off the landing gear
motor when fully extended or retracted?
http://www.matronics.com/forums/viewtopic.php?t=101826
_
Isn't a pilot more likely to fail than a switch or relay? There is a saying that
there pilots who have forgotten to put the gear down and pilots who will.
How about a circuit that will automatically extend the gear?
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=487914#487914
Message 6
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| Subject: | Re: Insulator in durable gas tight compression |
Bob, Joe, Dick, thank you.
This is exactly what I meant - is it possible to combine mechanical
connection, isolated, with electrical connection, gas tight as required,
by compressing the whole lot. It appears not - the functions have to be
separated because the isolating panel material is likely to relax too
much. In any case it looks like it is not in the accepted toolbox.
Sorry I caused confusion.
Jan de Jong
On 3/4/2019 6:48 PM, Dick Tasker wrote:
> <dick@thetaskerfamily.com>
>
> I believe you are asking is it okay to use some sort of laminate in
> the stack-up of layers wherein the goal is to have something to mount
> the connection to and insulate it from your airplane sheet metal and
> that will not affect the "gas-tightness" of the connection.
>
> If that is the question, I believe that the answer would be that there
> are very few materials that would allow that. Ceramic would work, but
> that is hared to work with. Any plastic type material probably is too
> soft to not allow some relaxation over time of the joint.
>
> The way to do what I think you want is to connect the bolt (or
> whatever is part of the whole assembly) to the laminate with a nut and
> then put the ring-lug (or whatever needs to be connected) onto the
> bolt and then use another nut to make the connection gas tight. Or if
> you are just using the laminate to hold the joint in place, place the
> two lugs that need to be connected over the first nut and then use the
> final to make it gas tight.
>
> If I have misinterpreted your goal, then just ignore this comment.
>
> Dick Tasker
>
> Jan de Jong wrote:
>> <jan_de_jong@casema.nl>
>>
>> I have a simple question.
>> Is there any example in acceptable practices where an insulating
>> layer (some laminate?) is part of the stack of metal layers that is
>> compressed to ensure a durable gas tight low resistance electrical
>> connection between the metal layers?
>> If there is such that would be great. If such can be categorically
>> denied that would be great too.
>> Thanks.
>> Jan de Jong
>>
>>
>>
>>
>>
>
>
Message 7
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| Subject: | Re: Insulator in durable gas tight compression |
...
I was actually looking at very hard phenolic laminates and other hard
insulating materials and considering Belleville washers etc. at
McMaster. when I decided to pose my question as a sanity check. I do not
plan to experiment with my electrical connections.
Thanks,
Jan de Jong
On 3/4/2019 9:09 PM, Jan de Jong wrote:
> <jan_de_jong@casema.nl>
>
> Bob, Joe, Dick, thank you.
> This is exactly what I meant - is it possible to combine mechanical
> connection, isolated, with electrical connection, gas tight as
> required, by compressing the whole lot. It appears not - the functions
> have to be separated because the isolating panel material is likely to
> relax too much. In any case it looks like it is not in the accepted
> toolbox.
> Sorry I caused confusion.
> Jan de Jong
>
> On 3/4/2019 6:48 PM, Dick Tasker wrote:
>> <dick@thetaskerfamily.com>
>>
>> I believe you are asking is it okay to use some sort of laminate in
>> the stack-up of layers wherein the goal is to have something to mount
>> the connection to and insulate it from your airplane sheet metal and
>> that will not affect the "gas-tightness" of the connection.
>>
>> If that is the question, I believe that the answer would be that
>> there are very few materials that would allow that. Ceramic would
>> work, but that is hared to work with. Any plastic type material
>> probably is too soft to not allow some relaxation over time of the
>> joint.
>>
>> The way to do what I think you want is to connect the bolt (or
>> whatever is part of the whole assembly) to the laminate with a nut
>> and then put the ring-lug (or whatever needs to be connected) onto
>> the bolt and then use another nut to make the connection gas tight.
>> Or if you are just using the laminate to hold the joint in place,
>> place the two lugs that need to be connected over the first nut and
>> then use the final to make it gas tight.
>>
>> If I have misinterpreted your goal, then just ignore this comment.
>>
>> Dick Tasker
>>
>> Jan de Jong wrote:
>>> <jan_de_jong@casema.nl>
>>>
>>> I have a simple question.
>>> Is there any example in acceptable practices where an insulating
>>> layer (some laminate?) is part of the stack of metal layers that is
>>> compressed to ensure a durable gas tight low resistance electrical
>>> connection between the metal layers?
>>> If there is such that would be great. If such can be categorically
>>> denied that would be great too.
>>> Thanks.
>>> Jan de Jong
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
Message 8
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| Subject: | Re: Insulator in durable gas tight compression |
You can use two nuts on the bolt. The first nut holds the bolt in place on the
insulating material. The electrical ring terminals go on next followed by the
second nut. The two nuts compress the terminals together with no plastic in between.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=487922#487922
Message 9
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| Subject: | Re: Insulator in durable gas tight compression |
Yes, separating the functions of locating and connection.
On 3/4/2019 11:57 PM, user9253 wrote:
>
> You can use two nuts on the bolt. The first nut holds the bolt in place on the
> insulating material. The electrical ring terminals go on next followed by the
> second nut. The two nuts compress the terminals together with no plastic in
between.
>
> --------
> Joe Gores
>
Message 10
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| Subject: | Re: Landing gear electric actuator circuit |
Le 04/03/2019 19:22, user9253 a crit:
> How about a circuit that will automatically extend the gear?
>
Joe and all,
This has been done before.
Some years ago I flew a PA28 with a special probe to automatically
extend the gear below a certain airspeed. Due to nuisance gear
extensions, an AD (or was it just an SB ?) had been issued to disable
the device.
Some airplanes have a horn going off any time the throttle is pulled to
idle with the gear up, etc.
The horn could be a good idea - but of course it will sound anytime you
reduce power in flight...Unless you add an airspeed sensor (how do you
establish the speed threshold ?), ground height sensor...
I'd personnally beware of any device trying to do my job in my place :
what when flying an airplane with *no* gear auto-extender ?
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
Message 11
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| Subject: | Re: Landing gear electric actuator circuit |
On 04/03/2019 8:08 PM, GTH wrote:
>
> Le 04/03/2019 19:22, user9253 a crit:
>> How about a circuit that will automatically extend the gear?
>>
>
> Joe and all,
>
> This has been done before.
>
> Some years ago I flew a PA28 with a special probe to automatically
> extend the gear below a certain airspeed. Due to nuisance gear
> extensions, an AD (or was it just an SB ?) had been issued to disable
> the device.
>
> Some airplanes have a horn going off any time the throttle is pulled
> to idle with the gear up, etc.
>
> The horn could be a good idea - but of course it will sound anytime
> you reduce power in flight...Unless you add an airspeed sensor (how do
> you establish the speed threshold ?), ground height sensor...
>
> I'd personnally beware of any device trying to do my job in my place :
> what when flying an airplane with *no* gear auto-extender ?
>
I don't like giving any control over to electronic devices but I
consider warning devices to be extremely valuable. The challenge is that
they must not nuisance trip which trains us to ignore them. These days
it is relatively cheap to incorporate ground sensing devices or gps
altitudes (with a database) into the warning logic.
Ideally we'd never hear such warnings and would not count on them
whether the aircraft had such a device or not. Interesting that the
same concerns are very applicable to current automotive systems.
philosophy according to Ken...
Message 12
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| Subject: | Re: Landing gear electric actuator circuit |
Given the aerodynamics today, why bother with folding gear? Good wheel
pants and gear fairings today have the speed penalty down to around 5
kts at typical general aviation speeds. I had a Mooney that would do
150-155kts on 10 gph. I now fly an RV-10 with fixed gear that does the
same speed on the same fuel flow (and faster if I want to burn more
fuel). It has bigger fuselage/cabin and same number of seats and useful
load as the Mooney, with bigger engine..so not truly apples to apples.
Just the speed gains may not be worth the cost/risk. JMHO after 18 yrs
of flying retractable, without a mishap...other than the gear mechanism
failing on different brand, but managed to still land it on the wheels.
On 3/4/2019 7:24 PM, C&K wrote:
>> Le 04/03/2019 19:22, user9253 a crit:
>>> How about a circuit that will automatically extend the gear?
Message 13
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| Subject: | Re: Landing gear electric actuator circuit |
The Bellanca super Viking also had a mechanism called auto-axion which would lower
the gear when the airspeed dropped. Below 90 mph. It worked well and only
became a problem when practicing stalls. We would, from my memory, jjust pull
the breaker to defeat it. It was a simple pitot pressure activated switch. The
arrow was more complex and had its own pitot tube mounted near the pilots window.
As mentioned before it was less than successful. The bellanca system, on
the other hand , was successful.
We of the canard persuasion do have an option of automatic nose gear extension
based on pitot pressure. It contains some logic to enable defeat when desired.
The main problem I see with any auto system is that a pilot may become less than
diligent and rely on the security of the automation
Rich
Sent from my iPhone
> On Mar 4, 2019, at 7:08 PM, GTH <gilles.thesee@free.fr> wrote:
>
> time
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