Vibration Monitor (Hyde, Wanttaja?)

If you wait that long, you're probably more concerned if the chain that's
holding the motor to the firewall is going to break after the motor cuts
loose from the mounts. All too often, the vibrations start to pick up
seconds or miliseconds before a catastrophic failure.

To do such a health-monitoring function properly, you really want some
seeded fault data to characterize what a "bad" engine spectrum looks like.
How many engines do you want to sacrifice to get the data? You can
approach
it from the "anything different from a healthy engine signature"
standpoint,
but that will likely result in a ton of false positive fault indications.


Are you suggesting that a bad engine will give clues to it's demise enough
in advance that you could actually do something about it? Clues that a
monitor could pick up on, but an experienced pilot wouldn't?

Of course. It has been done. Depends on the failure mode, of course. There
are some failure modes that take a long time to develop that give early
indications, and some that don't. A ton of work has been done in this area
for military jet engines. Seeded fault test data is the key to this.
Unfortunately, that might mean wrecking a bunch of engines to get the data.
It's not a project for the average home-builder.

Personally, I wouldn't bother trying to get a vibration caution together for
a home-built. Doing right would be just way too expensive. It would be
cheaper to just buy something that's turbine-powered and get rid of the
hazards that way. Besides, a huge number of failure modes already show up in
CHT's, EGT's, RPMs, etc. You have to weigh the cost of covering additional
failure modes against the hazards. This is really a job for engine
manufacturers. Additionally, you have to take complexity and reliability of
the sensing and processing into account. A monitor that is always going
haywire on you would be worse than nothing at all.

I'm actually looking at some stuff like this for possible inclusion on a
future project right now for a different type of powerplant. If you can
reliably predict RUL (remaining usable life) for a critical component, it
could be possible to reduce the amount of redundancy in a complex system and
rely on health monitoring functions to let you know when it's time to
replace the part.

PHM (prognostics and health management) has been a big focus in the military
aircraft world in recent years. I'm hoping that some of this technology will
trickle down to us in the GA world. Hmm...maybe I should get with an engine
manufacturer and work something out... SO, how much would people pay for an
engine health monitoring system package as an option for a new engine (i.e.
one of the new generation...maybe a DeltaHawk)? My guess is that it would be
too expensive to ever sell.

Pete


"LCT Paintball" wrote in message
news:ipA0e.102105$Ze3.20828@attbi_s51...
Are you suggesting that a bad engine will give clues to it's demise enough
in advance that you could actually do something about it? Clues that a
monitor could pick up on, but an experienced pilot wouldn't?

Pete Schaefer wrote:

PHM (prognostics and health management) has been a big focus in the military
aircraft world in recent years. I'm hoping that some of this technology will
trickle down to us in the GA world.

One useful technology that keeps getting more real are self-powered
sensors that communicate via bluetooth or other wireless, so you could
just stick them on various places and not have to worry about cabling
and all those other points of failure.

Cool. Maybe we should do entire airplanes around bluetooth. That way, any
geek with a PDA can hack our planes when we fly by. Yeah, **** all these EMI
worries!

Sorry, but that idea sounds like an awfully inviting drive-by target.

"nafod40" wrote in message
...
One useful technology that keeps getting more real are self-powered
sensors that communicate via bluetooth or other wireless, so you could
just stick them on various places and not have to worry about cabling
and all those other points of failure.

Pete Schaefer wrote:
Cool. Maybe we should do entire airplanes around bluetooth. That way, any
geek with a PDA can hack our planes when we fly by. Yeah, **** all these EMI
worries!

Sorry, but that idea sounds like an awfully inviting drive-by target.

Bluetooth has a limited range -- about 10m absolute max. Do you often
fly overhead geeks at 36ft AGL?

Not only that, but Bluetooth also allows closed networks to be set up --
no access to anyone outside the selected group of devices.

Sorry, but you shouldn't get all sarcastic about someone suggesting a
technology that you clearly don't have a clue about.

Frank

Frank:

I do have quite a clue about EMI, and clearly have a better clue than you
about systems engineering in general. Here's a question for you:

Why bother?

If you're trying to cert bluetooth for aviation, maybe with the thought of
selling some other bluetooth product that you think you can make a big chunk
of cash with, then, yeah, maybe going off to play with bluetooth on your
airplane makes sense. Personally, I can't see it. Maybe it makes sense for
using it to reprogram boxes on your airplane, but to go to the extent of
making it useful/safe in flight....nah. Way too much effort for too little
return, given that the inclusion of an RS-232 port is so freakin' easy.

If you have some other goal in mind, maybe some other sensing or data fusion
tech (e.g. may you have a huge array of air data sensors for some advance
stall detection method), then you have to look at whether or not the tech
risk buys you something that you can't get otherwise. Why bluetooth rather
than the 1/2 dozen other wired data communication protocols (e.g. 1392, .
422, 232, 485, CAN, etc.) that are out there?

I get rather frustrated with people who get really !@#$ing enamored with
technologies for implementation and loose sight of what their goals are. All
too often, risk variables get introduced where none is warranted, resulting
in zero or negative value added. I beat on my guys daily about issues like
this. (Kelly Johnson (...yeah, I work at that place.....) had a lot to say
about where it was acceptable to take project risks..too bad so much of it
never got captured in "the rules").

So, back to Blue Tooth....

Why bother?

For data collection, I've already got a half-dozen options in my hip pocket
that I know will work just fine with very well understood EMI issues that I
know how to mitigate. What's my goal? Blue tooth airplane or getting the
data for some other purpose?

I have very little room for Geek Factor on any airplane that I'll ever
build. If it can't buy it's way on (I'd lump Blue Tooth in here), then !@#$
it.


Pete

P.S. I just got done with a 5 hour drive and am tired as all !@#$. I've got
4 beers in me to diffuse stress. Please forgive my abbrasiveness. I'm not
really that bad of a guy. I just don't want people to pursue ideas that
will get them killed.


"Frank van der Hulst" wrote in message
...
Sorry, but you shouldn't get all sarcastic about someone suggesting a
technology that you clearly don't have a clue about.

Pete Schaefer wrote:
Frank:

I do have quite a clue about EMI, and clearly have a better clue than you
about systems engineering in general. Here's a question for you:

Why bother?

For the same reason that we build planes instead of buying them.

If you're trying to cert bluetooth for aviation, maybe with the thought of
selling some other bluetooth product that you think you can make a big chunk
of cash with, then, yeah, maybe going off to play with bluetooth on your
airplane makes sense. Personally, I can't see it. Maybe it makes sense for
using it to reprogram boxes on your airplane, but to go to the extent of
making it useful/safe in flight....nah. Way too much effort for too little
return, given that the inclusion of an RS-232 port is so freakin' easy.

I agree totally. except maybe about RS-232. I suggest that some sort of
current-based rather than voltage-based signalling would be more
noise-immune. Bring back 20mA current loop! :-)

If you have some other goal in mind, maybe some other sensing or data fusion
tech (e.g. may you have a huge array of air data sensors for some advance
stall detection method), then you have to look at whether or not the tech
risk buys you something that you can't get otherwise. Why bluetooth rather
than the 1/2 dozen other wired data communication protocols (e.g. 1392, .
422, 232, 485, CAN, etc.) that are out there?

The TWO key ideas in the proposition (wasn't mine, BTW) were wireless
comms and self-powered. If you can do BOTH of those, then wired comms
and power is best. Wireless comms has been pretty much solved. For
example, I saw a projection in an engineering mag that within 25 years
wireless will replace wired as the cheapest comms technology to the home.

But without "self-powered" it is pointless. Are there any devices out
there that can turn (e.g.) vibration into *useful* amounts of electricity?

I get rather frustrated with people who get really !@#$ing enamored with
technologies for implementation and loose sight of what their goals are.

Hmmm... so what are *my* goals? Maybe I want the geekiest plane on the
block? I suggest that one or other of your 4 beers has introduced some
patronisation (as well as abrasiveness) into your system.

All
too often, risk variables get introduced where none is warranted, resulting
in zero or negative value added.

I'll choose what risks are warranted on *my* project, thanks.

I beat on my guys daily about issues like
this. (Kelly Johnson (...yeah, I work at that place.....) had a lot to say
about where it was acceptable to take project risks..too bad so much of it
never got captured in "the rules").

This is fine where *you* get to set the goals.

So, back to Blue Tooth....

Why bother?

*With* self-powered devices, it gives options not available via wired
systems.

For data collection, I've already got a half-dozen options in my hip pocket
that I know will work just fine with very well understood EMI issues that I
know how to mitigate. What's my goal? Blue tooth airplane or getting the
data for some other purpose?

I have very little room for Geek Factor on any airplane that I'll ever
build. If it can't buy it's way on (I'd lump Blue Tooth in here), then !@#$
it.


Pete

P.S. I just got done with a 5 hour drive and am tired as all !@#$. I've got
4 beers in me to diffuse stress. Please forgive my abbrasiveness. I'm not
really that bad of a guy. I just don't want people to pursue ideas that
will get them killed.

Hey, I prefer to talk straight too. And also don't want people to kill
themselves. But if people don't experiment with Experimental category
aircraft, then nothing is going to change.

Frank

Frank:

P.S. Your're right...I don't know **** about the specifics of Blue Tooth.
I'm glad to admit it.

"Frank van der Hulst" wrote in message
...
Sorry, but you shouldn't get all sarcastic about someone suggesting a
technology that you clearly don't have a clue about.

Frank

Pete Schaefer wrote:
Cool. Maybe we should do entire airplanes around bluetooth. That way, any
geek with a PDA can hack our planes when we fly by. Yeah, **** all these EMI
worries!

Sorry, but that idea sounds like an awfully inviting drive-by target.

The idea that some sensors sending their signals via bluetooth to a data
recorder instead of cabling could be "hacked", whether from a PDA
standing outside the plane or from 5,000 feet AGL is silly. The EMI
argument is an open one, but the FAA rule says...

"a) Except as provided in paragraph (b) of this section, no person may
operate, nor may any operator or pilot in command of an aircraft allow
the operation of, any portable electronic device on any of the following
U.S-registered civil aircraft:


(1) Aircraft operated by a holder of an air carrier operating
certificate or an operating certificate; or
(2) Any other aircraft while it is operated under IFR.

(b) Paragraph (a) of this section does not apply to--

(1) portable voice recorders;
(2) hearing aids;
(3) heart pacemakers;
(4) electric shavers; or
(5) any other portable electronic device that the operator of the
aircraft has determined will not cause interference with the navigation
or communication system of the aircraft on which it is to be used.

It's coming to aircraft. In fact, it's already there via people that
don't turn off their cell phones and laptops etc., just uncontrolled.
Good article.

http://developer.intel.com/technolog...cles/art_4.htm

I've always wanted 100T ethernet thru the entire avionics stack.
Adding Bluetooth to the portable devices makes perfect sense!