Searching \ for '[EE]: Airplane cruise control' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=airplane+cruise
Search entire site for: 'Airplane cruise control'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: Airplane cruise control'
2002\06\12@204816 by Jinx

face picon face
I've been asked to look at a cruise control for a single-
engined light plane. I got the request via an intermediary,
who doesn't know a lot of details except that

(1) the micro should maintain the sensor input at 200Hz by

(2) sending a DC pulse to a pitch-control servo on the propellor

It seems "simple" enough, under ideal conditons anyway, but
if any of the licenced pilots on the list have any comments I'd
be glad to hear them. There will be real life factors to take
into consideration, eg buffeting, plane loading, time needed to
change pitch etc

Also, I have my hourly rate of course, and have a rough idea
what time is involved in the initial stages at least, but have
no idea what a commercially available unit costs. Possibly
the enquirer can't afford a unit off the shelf, I don't know. Any
ideas ? I'd just like to know whether I'm hundreds or thousands
of dollars off-beam. As there could be a small run follow up,
it would be nice to know I could actually get a reasonable return

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\12@210836 by Pic Dude

flavicon
face
I've never had the opportunity to fly an airplane with
cruise control, but with other autopilot systems (heading
and altitude being most popular in my experiences).  There's
not a really big push to maintain a specific airspeed, except
for maybe when in a speed-restricted zone and you have an
airplane that will exceed that.  Usually most pilots will
set a specific manifold pressure/throttle setting and let
the airplane do what it can speed-wise.

My guess is that you will run into significant red-tape with
regulations/certification.  Pick up an airplane magazine and
look thru the ads for the brands of these systems, then
contact the manufacturers for their distrubutors, and hence
pricing.  Names like Bendix/King, Narco, UPS (yes the same
shipping company), JP instruments, and PS Engineering come
to mind.  Contact the FAA in the US or other group in other
parts of the world and get the equipment standards &
certification docs.  In the US, the AOPA is also helpful
with stuff like this, but there may be another similar org
in your neck of the woods.

BTW, pilots may not be as helpful as aircraft owners, or
ideally: A&P mechanics.

Hope it helps,
-Neil.



{Original Message removed}

2002\06\12@214101 by Jinx

face picon face
>
> My guess is that you will run into significant red-tape with
> regulations/certification.

I'm expecting that - public safety etc. So it's by no means
certain that this will go ahead. Had a similar problem
recently offering to do house improvements for someone.
Job and materials was the easy bit. Eventually didn't get
done because of expensive council and govt BS

> Pick up an airplane magazine and look thru the ads

Yeah, I'll be doing that, just thought someone here may
have some quick and ready info

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\13@003455 by Bob Japundza

flavicon
face

I'm a private pilot, bonafide airplane nut and have built one experimental aircraft (Van's Aircraft RV-6) and am currently building an F1 Rocket, so I guess I can help you out here...on an experimental home-built aircraft pretty much anything goes so you could legally build a control for the prop and fly it as you wish.

Sounds like what this person wants is a governor for an electric constant-speed propeller; there's no such thing as a cruise control for airplanes.  I have a Hartzell constant-speed prop on my RV-6 and it is hydraulically controlled via a governor that is mounted on the back of my engine.  The advantage of a constant-speed propeller over a fixed pitch propeller is akin to the difference between a transmission with only one gear ratio and one that has a variable speed drive.  They outperform fixed-pitch props on several orders of magnitude.  You can always maintain an efficient RPM for climb or cruise so the prop can absorb the most power in a given flight regime without "loading" the engine.  With a fixed-pitch prop, the RPM varies with the airspeed of the aircraft, so if you pull the nose up the RPM will drop or if you point the nose down you can overspeed the engine.  Several props are available for experimental aircraft that have an electric pitch-change mechanism, thus not hydraulically-controlled like most of them are.  I assume this person wants to build a control for one of these propellers, as the control (governor) may be expensive, costing several thousand dollars.  Basically, with a constant-speed propeller, you set the RPM with the prop control lever, and the throttle controls manifold pressure.  The governor maintains the RPM of of the engine by varying the pitch of the blades.  So once you set the RPM, any time airspeed changes the governor changes the pitch of the blades to maintain the RPM you set with the prop control.  As far as what you need to do with something like a PIC, you would have a prop control to set RPM and an RPM sensor to maintain the RPM you have set with PID/PWM routines.  Probably would also have an LCD that displays RPM, too.

For a better explanation of how constant-speed props work, check out www.spa-training.com/constant_speed_props.htm.

Bob


       {Original Message removed}

2002\06\13@014057 by Dave King

flavicon
face
> > My guess is that you will run into significant red-tape with
> > regulations/certification.
>
>I'm expecting that - public safety etc. So it's by no means
>certain that this will go ahead. Had a similar problem
>recently offering to do house improvements for someone.
>Job and materials was the easy bit. Eventually didn't get
>done because of expensive council and govt BS

There are a few certified electric props and they are worth quite a few $$
Hoffman is one of the big ones and you can kiss about $8K++ goodbye to
start. There are other non certified props such as Warp and Ivo that have
inflight adjustable props. Both of those have problems with various parts
of the control mechanism. Even those will set you back about $2K.

To certify the part you would be looking at 10's of thousands of cubic $
for the basic part. The testing is involved and require people with alphabets
to write various reports and tests.

If he's doing it for a amateur or home built then you don't have restrictions
other than a couple of sue happy people who were trying to go after anyone
building a governor for one of these. I think they stopped doing that a few
years ago.

Yeah, I'll be doing that, just thought someone here may
>have some quick and ready info

Sounds like a few people here fly, just need a bit more info on what he's
working with.
Worked out the software for it a few years ago using a 8051 and a hall sensor.

Dave

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\13@015736 by Jafta

flavicon
face
Hi Jinx

Only the VERY expensive AC used in airlines have speed control - and
they are turbo jets/fans.  Speed control with the prop pitch will not
work either, as the change in RPM to maintain airspeed will be very
big indeed.  All CS props has a min/max angle that the blades will
deflect.

Low reving AC engines - like Lycoming, Continental et al - have not
been built to change speed quickly like a car engine. It might be
different with the small screamers like Rotax and co.

Two factors contribute to the speed of an AC engine - manifold
pressure, and the RPM setting.  Changing either of these will affect
the other.

And then you have to decide at which speed you want to set the
cruise - Indicated Air Speed, True Air Speed, or Ground Speed - which
will be a different calculation all together.

I have some tech info on this from my CP course which I can let you
have if you are interested.

Regards

Chris Albrecht



{Original Message removed}

2002\06\13@020131 by Jinx

face picon face
> Sounds like a few people here fly, just need a bit more info on
> what he's working with

Bob Japundza's post summed it up very well - thank you Bob

And thank you Dave for your reply too. The prices you
mentioned are in the ball park of the one engineer I
did manage to speak to this afternoon

Being late in the day now in NZ, and I could only start
ringing around at 5pm, I don't have much more info
yet, but I've been referred to a couple of web sites by
that engineer. I should have more details by tomorrow

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\13@020754 by Jinx

face picon face
> I have some tech info on this from my CP course which I
> can let you have if you are interested.
>
> Regards
>
> Chris Albrecht

Cheers. I've been thrown in at the deep end, completely
ignorant about this type of control. I just need to get my
thoughts together and have a chat to the enquirer if I can

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\13@111650 by Lawrence Lile

flavicon
face
Jinx, from a liability standpoint I would not touch this with a ten-foot
landing gear spar.

Just my $0.02, adjusted for inflation

--Lawerece

{Original Message removed}

2002\06\13@113140 by Paul Hutchinson

flavicon
face
Can't help with the tech stuff but I do have one piece of advice.

Make sure your liability insurance coverage is appropriate. If you are named
in a lawsuit, even a frivolous lawsuit, you want to have the backing of your
insurance carrier to cover the legal expenses.

Paul

> {Original Message removed}

2002\06\13@150349 by Dave King

flavicon
face
At 11:29 AM 13/06/02 -0400, you wrote:
>Can't help with the tech stuff but I do have one piece of advice.
>
>Make sure your liability insurance coverage is appropriate. If you are named
>in a lawsuit, even a frivolous lawsuit, you want to have the backing of your
>insurance carrier to cover the legal expenses.
>
>Paul

There has never been a successful lawsuit involving experimental
aircraft  even in
the US. That doesn't mean you couldn't experience  some legal fee's. And
generally they tend to do a sue/serve first and sort them out later routine.
In other words you could get named but as soon as they find out your pockets
are just deep enough to hold small change they stop.

Plus he's in NZ which like us (Canucks) use a different standard for civil
suits
than the US. You have to prove actual damages not just pain and suffering.
Here if you sue and loose you get to pay everyone's legal fee's as well so
you have to be right. To do anything to him he'd have to be sued in NZ anyway.
assuming that he intended to make this a commercial product not just a one off
which he hasn't said yet.

Lawyers are like nukes. As long as you don't use them everything is fine,
as soon
as you do everything gets F'd up ;-]

Dave

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\13@151404 by Bob Japundza

flavicon
face
True, but there have been settlements with kitplane manufacturers, but not the kitplane builders themselves.

Having a fat insurance policy is bait for the injury attorneys that take out full-page ads in the backs of phone books.  Those bastards are the ones that have made flying so expensive.

Bob

> {Original Message removed}

2002\06\13@161231 by Dave King

flavicon
face
At 02:13 PM 13/06/02 -0500, you wrote:
>True, but there have been settlements with kitplane manufacturers, but not
>the kitplane builders themselves.
>
>Having a fat insurance policy is bait for the injury attorneys that take
>out full-page ads in the backs of phone books.  Those bastards are the
>ones that have made flying so expensive.
>
>Bob

Bob

Your not suggesting that anyone involved in aviation doesn't have bags of
money lying around the house? I've heard those RV guys are loaded ;-]

Cheers

Dave

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\13@162305 by Paul Hutchinson

flavicon
face
I did not see any reference to this being an experimental aircraft.
I just saw this from the original message:
>I've been asked to look at a cruise control for a single-
>engined light plane.
I assumed he was referring to a plane like a Cessna.


I read this part of the original message to mean that he might do a
production run of these devices.
>I'd just like to know whether I'm hundreds or thousands
>of dollars off-beam. As there could be a small run follow up,
>it would be nice to know I could actually get a reasonable return

If in fact it's an experimental plane and it's a one off device then I
wouldn't worry much about liability. Although I'd probably get a signed
waiver from the person doing the flyer so that the heirs can't sue.

If however it's going to be produced in some quantity and sold to the flying
public I still suggest checking the liability coverage. Not much worse than
having your liability carrier tell you no that wasn't covered after
something comes up. Much safer to at least ask about it first regardless of
where you live.


Paul

> {Original Message removed}

2002\06\13@170211 by Bob Japundza

flavicon
face
heh...I traded all the green stuff I had for a bunch of aluminum.  My wife calls it the "hobby from hell."

Bob

> {Original Message removed}

2002\06\13@175800 by Jinx

face picon face
> >Make sure your liability insurance coverage is appropriate. If
> you are named in a lawsuit, even a frivolous lawsuit, you want
> to have the backing of your insurance carrier to cover the legal
> expenses.

I found out, through devious means, that the enquirier is already
in the light plane industry, and more than likely just looking for a
less expensive product that's made locally, rather than a US
import. AFAIK he has propellors but no control electronics. He's
therefore aware of rules and regs concerning experimental vs
production runs, in which case I'd be happy to do some work for
him. I'm waiting for a reply from the NZ Civil Aviation fellas for
my own benefit

Anyone following the thread and not sure what is being
talked about (yeah, like I'm the big expert already) have
a look here

http://www.propellor.com

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\14@095754 by Roman Black

flavicon
face
Jinx wrote:
>
> I've been asked to look at a cruise control for a single-
> engined light plane. I got the request via an intermediary,
> who doesn't know a lot of details except that


Wow! A request for a self-flying aeroplane, coming
from a "intermediary", and nobody on the list raised
a suspicious eyebrow??

I don't suppose the "intermediary" asked about the
GPS coords of govt or military installations? Or the
minimum altitudes that radar would pick up the 'plane?
;o)
-Roman

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spam_OUTlistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body


2002\06\14@102643 by Alan B. Pearce

face picon face
>I don't suppose the "intermediary" asked about the
>GPS coords of govt or military installations? Or the
>minimum altitudes that radar would pick up the 'plane?
>;o)
>-Roman

Shucks Roman, he would have a job getting a plane of that size to fly from
him to you without worrying about having a payload that would do damage to a
military installation :)))

There ain't hardly anything in NZ worth flying a 'plane into apart from the
odd mountain and the skytower :) Hang on maybe that's what he wanted it for
:))

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body


2002\06\14@102902 by Tal Dayan

flavicon
face
I hope this is not shipped to Saudi Arabia as the remote activation device
that was mentioned here a week or two ago.

FBI, it's time to turn on Carnivore
(http://www.robertgraham.com/pubs/carnivore-faq.html).

;-)

Tal

> {Original Message removed}

2002\06\14@103731 by Eoin Ross

flavicon
face
There is the Waihopi sattelite receiving/tracking station - part of the US worldwide communications spying network, and operation Deep Freeze (US military planes flying to Antarctica)

But then the request it appears is for cruise control - not autopilot

>>> A.B.PearcespamKILLspamRL.AC.UK 06/14/02 10:26AM >>>
>I don't suppose the "intermediary" asked about the
>GPS coords of govt or military installations? Or the
>minimum altitudes that radar would pick up the 'plane?
>;o)
>-Roman

Shucks Roman, he would have a job getting a plane of that size to fly from
him to you without worrying about having a payload that would do damage to a
military installation :)))

There ain't hardly anything in NZ worth flying a 'plane into apart from the
odd mountain and the skytower :) Hang on maybe that's what he wanted it for
:))

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2002\06\14@110021 by Pic Dude

flavicon
face
I'm curious how "cruise control" got interpreted as
"self-flying".  Thinking of selling my car, maybe I should
advertise it as "Self-driving -- sleep while it takes you
to your destination!"  :-)

This is just speed control he was asking about.  There are
already autopilot systems on even very small aircraft that
will maintain a heading and altitude, which I think are more
of an issue.

Cheers,
-Neil.


{Original Message removed}

2002\06\14@183527 by Jinx

face picon face
> There is the Waihopi sattelite receiving/tracking station -
> part of the US worldwide communications spying network,
> and operation Deep Freeze (US military planes flying to
> Antarctica)

Ach - infidel !!!!! ;-)

The application is for propellor control only, through control
of a reasonably spunky DC motor and gearbox

=======================================

btw, David Letterman in his news round-up monologue
yesterday said Bin Laden is suspected of having a
recruitment camp for Al Qaeda in Florida, which explains
the number of old people who drive into buildings

Insensitive ? Probably. But it shows how a country
bounces back with some spirit

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email EraseMElistservspam_OUTspamTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body


2002\06\15@024513 by Roman Black

flavicon
face
Pic Dude wrote:
>
> I'm curious how "cruise control" got interpreted as
> "self-flying".  Thinking of selling my car, maybe I should
> advertise it as "Self-driving -- sleep while it takes you
> to your destination!"  :-)


Ummm, not self-flying? So exactly what purpose DOES
a cruise control serve? Come on, in these troubled times
when small embedded consultants are approached to design
ANYTHING even related to self flying aeroplanes you
have to be a bit suspicious. And the added bit "I was
contacted through an intermediary" really made me grin.
Did the intermediary insist on a meeting on a park
bench where the design plans were handed over inside
a folded newspaper? ;o)
-Roman

--
http://www.piclist.com hint: To leave the PICList
piclist-unsubscribe-requestspamspam_OUTmitvma.mit.edu


2002\06\15@075853 by Jinx

face picon face
> Ummm, not self-flying? So exactly what purpose DOES
> a cruise control serve?

It's exactly the same as cruise control in a car. I spoke to the
actual person who wants the job done today. If I understand
him correctly it means less work for the pilot making minor
corrections to engine RPM during a flight. I presume from
this that it would make it easier to some degree to gauge
fuel usage if the engine is running at the same revs from
take-off to landing, as well as probably a more comfortable
flight for all concerned. He told me that on a recent trip from
Queenstown to Auckland (about 225mm. Hang on, it's more
than that surely. Oh right, there's a scale, er 700 miles) he
noted that the pitch control on this 4-seater cycled about
half a dozen times, but it was pretty clear air most of the way

He gave me some more details. The prop needs to be held
at a selectable speed betrween 2000 and 3000 rpm. There
are 6 magnetic sensors on the prop shaft that output 200 to
300Hz (eg (2000/60) * 6). There was also talk of adjustment
time, pilot controls, operational stuff like that. It's reasonably
straight-forward

> small embedded consultants

Can't argue with that. I'm 5'3" and people are always consulting
me. Like, "just when ARE you getting up ?"

> are approached to design ANYTHING even related to self
> flying aeroplanes you have to be a bit suspicious.

I wasn't concerned at all. To be honest, I didn't hear much
after the word "job" except a distant cash register going
"ching ching ching". One of "those" weeks. And NZ is so
small you can get up in the air and pretty well point out
anywhere in the country. GPS ? Waste o' money here.

Security is nowhere near as tight as you'd see in the US for
example and it would be easy to damage any of many soft
targets you wanted to with devices other than a plane. And
why would you bother with a light plane anyway ? Look at the
student who hit that building (the only high rise in a European
town) with a light plane. And I think one in Florida too. Broke
a couple of windows and killed themselves doing it

> And the added bit "I was contacted through an intermediary"
> really made me grin

If you've ever spoken to my acquaintance old Mr Harris you'd
be thinking that a terrorist organisation could do a little better
than use "him" as a go-between. He's not what you'd call "perky"

> Did the intermediary insist on a meeting on a park bench
> where the design plans were handed over inside a folded
> newspaper? ;o)

Well yes actually. But it was no bother - I was already down the
park trying out the new E-Z-Flash raincoat. Which is really great
btw, the 2002 VelcroMatic, beats buttons on a cold finger-
numbing day I can tell you

--
http://www.piclist.com hint: To leave the PICList
@spam@piclist-unsubscribe-requestKILLspamspammitvma.mit.edu


2002\06\15@101119 by Pic Dude

flavicon
face
I bet you save a lot of money by not going to movies. :-)



-----Original Message-----
From: pic microcontroller discussion list
[KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU]On Behalf Of Roman Black
Sent: Saturday, June 15, 2002 1:25 AM
To: RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU
Subject: Re: [EE]: Airplane cruise control


Pic Dude wrote:
>
> I'm curious how "cruise control" got interpreted as
> "self-flying".  Thinking of selling my car, maybe I should
> advertise it as "Self-driving -- sleep while it takes you
> to your destination!"  :-)


Ummm, not self-flying? So exactly what purpose DOES
a cruise control serve? Come on, in these troubled times
when small embedded consultants are approached to design
ANYTHING even related to self flying aeroplanes you
have to be a bit suspicious. And the added bit "I was
contacted through an intermediary" really made me grin.
Did the intermediary insist on a meeting on a park
bench where the design plans were handed over inside
a folded newspaper? ;o)
-Roman

--
http://www.piclist.com hint: To leave the PICList
spamBeGonepiclist-unsubscribe-requestspamBeGonespammitvma.mit.edu

--
http://www.piclist.com hint: To leave the PICList
TakeThisOuTpiclist-unsubscribe-requestEraseMEspamspam_OUTmitvma.mit.edu


2002\06\15@102214 by Pic Dude

flavicon
face
Hmmm.... not sure if this is clear or not, but I'll
say it just in case.  On an airplane, engine RPM is not
directly proportional to groundspeed (which is not the
same as airspeed, btw).  My guess is that you want to
be able to maintain a constant groundspeed, so there
will need to be some sensor(s) to gauge that, and perhaps
GPS is the way to go.

Also, revs are not proportional to fuel consumption.
Not just in airplanes, but also in cars.

Speaking of fuel, if you really want to do something
useful for the aviation community, how about building a
fuel gauge that senses the level at various points, and
perhaps also the motion of the aircraft to mathematically
calculate a more accurate fuel-level.

Cheers,
-Neil.


{Original Message removed}

2002\06\15@103252 by Alexandre Domingos F. Souza

flavicon
face
>Speaking of fuel, if you really want to do something
>useful for the aviation community, how about building a
>fuel gauge that senses the level at various points, and
>perhaps also the motion of the aircraft to mathematically
>calculate a more accurate fuel-level.

       Why not a gauge who meters the flow of fuel to the tank, and computes this flow against the know quantity of fuel on the tank? If the flow is 3 gallons/minute, and the tank has 30 gallons, you have 10 minutes of flight. It is just a matter of counting how much fuel has passed thru the flow meter...

       It cannot be as simple as that, but I cannot see an easier way


---8<---Corte aqui---8<----

Alexandre Souza
RemoveMEtaitospamTakeThisOuTterra.com.br
http://planeta.terra.com.br/lazer/pinball/

---8<---Corte aqui---8<----

--
http://www.piclist.com hint: To leave the PICList
piclist-unsubscribe-requestEraseMEspam.....mitvma.mit.edu


2002\06\15@103903 by Jafta

flavicon
face
I don't think that is too crucial - once you have properly planned
your flight, and you are flying the plan, the engine settings
determine your fuel economy.  You know how much fuel you have - you
used your dip stick, didn't you?  Of course, you would never trust the
gauges - but actually have a computer determining the best setting for
the mixture would be much easier than having the pilot fiddling with
the control.  How accurate is peak EGT less 25degC?  Let a PIC measure
the EGT, and control the mixture to within pre-set tollerances.  This
will stretch your gallons per seat mile.

And this will be moot when you fly a C208 or such.

Regards

Chris A

----- Original Message -----
From: "Pic Dude" <EraseMEpicdudespamAVN-TECH.COM>
To: <RemoveMEPICLISTEraseMEspamEraseMEMITVMA.MIT.EDU>
Sent: Saturday, 15 June, 2002 16:19
Subject: Re: [EE]: Airplane cruise control


Hmmm.... not sure if this is clear or not, but I'll
say it just in case.  On an airplane, engine RPM is not
directly proportional to groundspeed (which is not the
same as airspeed, btw).  My guess is that you want to
be able to maintain a constant groundspeed, so there
will need to be some sensor(s) to gauge that, and perhaps
GPS is the way to go.

Also, revs are not proportional to fuel consumption.
Not just in airplanes, but also in cars.

Speaking of fuel, if you really want to do something
useful for the aviation community, how about building a
fuel gauge that senses the level at various points, and
perhaps also the motion of the aircraft to mathematically
calculate a more accurate fuel-level.

Cheers,
-Neil.


{Original Message removed}

2002\06\16@063328 by Roman Black

flavicon
face
>
> > And the added bit "I was contacted through an intermediary"
> > really made me grin
>
> If you've ever spoken to my acquaintance old Mr Harris you'd
> be thinking that a terrorist organisation could do a little better
> than use "him" as a go-between. He's not what you'd call "perky"


I'm Soooo glad at least one person realised I was
joking, heck I thought it real obvious, even including
the mandatory "winky face" ;o)

Umm, old Mr Harris??? He's the gentleman that just
contracted me to build the "Cessna laser steering system"
although I still can't work out why he needs to make
the 'plane home in onto a red dot?? Funny old chap. ;o)

Now seriously Jinx, wouldn't a proper cruise control
need to be closed-loop to airspeed, ie monitored by GPS
and adjusted accordingly? If you do it closed-loop to
engine revs how useful can it be? Isn't it just a slightly
improved throttle and really how bad is the stock
throttle anyway? Doesn't it hold the revs constant
already?
-Roman

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@072041 by Jinx

face picon face
> Now seriously Jinx, wouldn't a proper cruise control
> need to be closed-loop to airspeed, ie monitored by GPS
> and adjusted accordingly? If you do it closed-loop to
> engine revs how useful can it be? Isn't it just a slightly
> improved throttle and really how bad is the stock
> throttle anyway? Doesn't it hold the revs constant

I'll quote you from Bob Japundza's post of a few days ago

"The advantage of a constant-speed propeller over a fixed
pitch propeller is akin to the difference between a transmission
with only one gear ratio and one that has a variable speed drive.
They outperform fixed-pitch props on several orders of magnitude.
You can always maintain an efficient RPM for climb or cruise
so the prop can absorb the most power in a given flight regime
without "loading" the engine.  With a fixed-pitch prop, the RPM
varies with the airspeed of the aircraft, so if you pull the nose up
the RPM will drop or if you point the nose down you can
overspeed the engine"

http://www.spa-training.com/constant_speed_props.htm

The propellors I'll be working with are 4-blade, with a planetary
gear driven by a DC motor to adjust the pitch. There are micro
switches at the limits too. According to others on the list and Mr
X himself, it is not all difficult. Mr X has no concerns about safety
either - he has a make-do governor built around a stepper on a
plane now that doesn't work half the time and he's quite relaxed,
even a little nonchalant, about it. The worst that can happen is
that the pilot simply takes over manually. I've been told that some
units available now cost around NZ$1500 and have unused and
unnecessary features which is encouraging

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@192600 by Peter L. Peres

picon face
On Sun, 16 Jun 2002, Jinx wrote:

>The propellors I'll be working with are 4-blade, with a planetary
>gear driven by a DC motor to adjust the pitch. There are micro
>switches at the limits too. According to others on the list and Mr
>X himself, it is not all difficult. Mr X has no concerns about safety
>either - he has a make-do governor built around a stepper on a
>plane now that doesn't work half the time and he's quite relaxed,
>even a little nonchalant, about it. The worst that can happen is
>that the pilot simply takes over manually. I've been told that some

I assume this is a one seater yes ? ;-( Or else Mr. X might be
over-insured. If Mr. X says it is not difficult then it must be easy.

Peter

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@194301 by Tony Nixon

flavicon
picon face
Jinx wrote:
>
> I've been asked to look at a cruise control for a single-
> engined light plane. I got the request via an intermediary,
> who doesn't know a lot of details except that
>
> (1) the micro should maintain the sensor input at 200Hz by
>
> (2) sending a DC pulse to a pitch-control servo on the propellor
>
> It seems "simple" enough, under ideal conditons anyway, but
> if any of the licenced pilots on the list have any comments I'd
> be glad to hear them. There will be real life factors to take
> into consideration, eg buffeting, plane loading, time needed to
> change pitch etc

I just passed my private pilots licence on Friday :-)))

I'd be cautious about doing anything "automated" to an aircrafts engine.
If an accident occurred and your device was the suspect.... the mind
could only boggle at the legal implications that would follow.

Imagine the 'box' taking control of the engine speed on short final, or
worse, just after leaving the ground, due to some weird software bug, or
some wiring fault - in the end, who's to say. Was it caused by you, the
installer (owner), or both.

Personally, I'd pass on the project, especially as there are a lot of
unknowns, and leave it to a company with mega bucks available for
possible law suits.

My limited experience with "real world" projects is that they take a lot
of time to debug and fine tune. Aircraft time is "expensive".

--
Best regards

Tony

mICros
http://www.bubblesoftonline.com
RemoveMEsalesspam_OUTspamKILLspambubblesoftonline.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@194927 by Jinx

face picon face
> I assume this is a one seater yes ? ;-( Or else Mr. X might be
> over-insured. If Mr. X says it is not difficult then it must be easy.

That example was a four-seater. During testing Mr X presumably
just takes people he doesn't like as passengers

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@195959 by Jinx

face picon face
> I just passed my private pilots licence on Friday :-)))

Congrats - placate the missus ?

> I'd be cautious about doing anything "automated" to an aircrafts
> engine.If an accident occurred and your device was the suspect....
> the mind could only boggle at the legal implications that would follow

I'd also be cautious about anything that affected the engine.
However this device merely alters the pitch of the propellor. If
it fails (touch wood) then all that happens is that either the
status quo is maintained or the pilot re-takes control. There's
no way the plane can just drop like a stone. I'm told it's quite
normal for the pilot to be "involved" only for take-offs and landings.
The rest of the time he's more or less just along for the ride,
the same as the passengers

> My limited experience with "real world" projects is that they
> take a lot of time to debug and fine tune. Aircraft time is
> "expensive"

Oh how true that can be. But Mr X is in the air a lot anyway
and for the reasons mentioned, it's not a device that in any
significant way affects the running of the plane. Obviously
there will be some fine tuning required, but the system the
PIC has to deal with is not overly-complicated, predictable,
and relatively slow to react

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@202109 by Tony Nixon

flavicon
picon face
Jinx wrote:
>
> Oh how true that can be. But Mr X is in the air a lot anyway
> and for the reasons mentioned, it's not a device that in any
> significant way affects the running of the plane. Obviously
> there will be some fine tuning required, but the system the
> PIC has to deal with is not overly-complicated, predictable,
> and relatively slow to react


I haven't followed this thread fully.

To my somewhat limited knowledge of variable pitch props, you may also
need to monitor the engine manifold pressure to keep the engine
operating optimally especially at altitude when the mixture might be
leaned. Too lean = bad news. How complicated this will get, I don't
know. Variable pitch props are the start of my next set of flying
lessons.


--
Best regards

Tony

mICros
http://www.bubblesoftonline.com
RemoveMEsalesTakeThisOuTspamspambubblesoftonline.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@203733 by Jinx

face picon face
> To my somewhat limited knowledge of variable pitch props,
> you may also need to monitor the engine manifold pressure
> to keep the engine operating optimally

Mr X is not concerned with manifold pressure. Armed with
the list's "instant knowledge" I was able to talk to him a little
more confidently than I would have otherwise. As he's in the
aviation industry he's aware of all the rules/regs/howtos and
does not require a system that uses anything other than the
prop speed (engine revs). That's not to say he's right, been
caught by so-called experts before now, but he seems to
know what he's talking about and for the time being I've no
reason or facts to persuade him otherwise. My aim initially
is to give him exactly what he's asking for. If (when) he's happy
with that then maybe there'll be more to follow

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@210057 by Dave King

flavicon
face
>To my somewhat limited knowledge of variable pitch props, you may also
>need to monitor the engine manifold pressure to keep the engine
>operating optimally especially at altitude when the mixture might be
>leaned. Too lean = bad news. How complicated this will get, I don't
>know. Variable pitch props are the start of my next set of flying
>lessons.
>
>Tony

Tony

Constant speed props do not directly or significantly affect the mixture of
the engine.

For the rest of you non-flier types..

Fixed pitch props are set to provide optimal thrust from the engine at one
condition of airspeed and engine power setting. For an example the 150
you might have trained on has a prop the is most efficient at about 95mph
in cruise or at 70 for climb. What you gain at one "setting" you loose out
at the others. If you fly from floats you want to thing to get off the
water asap
or if you do short field  you might want to climb at best rate or angle etc
while
someone else might want to go cross country and high speed or cruise is it.
The only props that are capable of doing all of them efficiently (more anyway)
is a in-flight adjustable which is the basic prop Jinx is playing with or a
constant speed
which is what he is converting it to.

There have been electrically controlled props like this since the 40's as
well as the more
common hydraulically controlled ones. The electric ones more or less use a
toggle switch
to adjust the pitch through a reversible geared electric motor. The pitch
"governor" is the nut behind
the stick aka the Pilot. They work fairly well but can bit a bit of work
when you do circuits
or "crash and dashs" as instructors call em. Where you can be playing with
the switch the entire
time. Works great however when you are going someplace.

These are not a cruise control as such but more of a rpm governor.

Dave

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\16@214222 by Tony Nixon

flavicon
picon face
Jinx wrote:
>
> > I just passed my private pilots licence on Friday :-)))
>
> Congrats - placate the missus ?

I'm very forgiving to the missus' needs, otherwise I'm grounded :-)

Last week, I volunteered to help with the building of a flight simulator
which is being constructed by the aero club for IFR use. From what I've
seen so far it has five monitor screens in use for instrument displays
and background veiws. Not quite sure what that entails yet, but I hope a
PIC here and there comes in handy.

--
Best regards

Tony

mICros
http://www.bubblesoftonline.com
EraseMEsalesspamspamspamBeGonebubblesoftonline.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\17@003755 by Graeme Zimmer

flavicon
face
Jinx,

Regarding Aircraft Cruise control....

In most aircraft, when you trim things up a the required height and speed
and then sit back, you can watch the aircraft slowly oscillate around your
set points. The nose drops slightly and the speed slowly builds up, which
causes the nose to rise, which causes the speed to slowly drop....

With much fiddling, you can usually get it stable for a while, and then as
you burn fuel and the weight distribution changes it starts all over again..

In a sedate training aircraft the effect is quite minor, but in a high
performance aircraft the effect is a best annoying and at worst dangerous...

By nailing one of the primary variables (e.g. RPM) the effect can be
entirely eliminated...   hence Cruise Control.

Be careful that controlling one of the secondary variables (e.g. pitch
rather than RPM), you don't actually make things worse...
(The nose drops slighty, the speed builds up, the revs increase, the pich
increases, the speed increases further ......)

................ Zim

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@010121 by Jinx

face picon face
> In a sedate training aircraft the effect is quite minor, but in a high
> performance aircraft the effect is a best annoying and at worst
> dangerous...

The testing schedule is all sorted out

Install unit
Test flight
Wet oneself
Land
Change clothing
Tinker with unit
Get into "happy place"
Test flight......

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@011841 by Tony Nixon

flavicon
picon face
Jinx wrote:
>
> > In a sedate training aircraft the effect is quite minor, but in a high
> > performance aircraft the effect is a best annoying and at worst
> > dangerous...
>
> The testing schedule is all sorted out
>
> Install unit
> Test flight
> Wet oneself
> Land

The following is variable, depending on how hard the landing was ;-)

> Change clothing
> Tinker with unit
> Get into "happy place"
> Test flight......
>


--
Best regards

Tony

mICros
http://www.bubblesoftonline.com
RemoveMEsalesKILLspamspambubblesoftonline.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@100058 by WASSON, KIRK D

flavicon
face
There a lot of real smart folks on this board. I have received great PIC information.
We should not be responding to requests for information on Cruise Controls.
Folks interested in cruise controls can get a response from: http://www.fbi.gov/
Keep America safe, Kirk

{Original Message removed}

2002\06\17@100937 by Michael Rigby-Jones

flavicon
face
> -----Original Message-----
> From: WASSON, KIRK D [SMTP:KWASSONSTOPspamspamspam_OUTENTERGY.COM]
> Sent: Monday, June 17, 2002 2:49 PM
> To:   spamBeGonePICLISTSTOPspamspamEraseMEMITVMA.MIT.EDU
> Subject:      Re: [EE]: Airplane cruise control
>
> There a lot of real smart folks on this board. I have received great PIC
> information.
> We should not be responding to requests for information on Cruise
> Controls.
> Folks interested in cruise controls can get a response from:
> http://www.fbi.gov/
> Keep America safe, Kirk
>
As has been stated, this is a CRUISE control we are talking about, not an
AUTOPILOT.  This is also for a light aircraft application.  IMO inferring
that discussing the finer points of propeller pitch control on a light
aircraft is compromising the security of the US is verging on paranoia.

Regards

Mike

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@101326 by Dale Botkin

flavicon
face
A little paranoia goes a long way.  The OP was not asking for help with an
autopilot or an automatic guidance system, both of which can be very
easily purchased commercially without any questions being asked anyway.
It's a prop pitch controller, guys, not a nuclear detonator.  Let's not
needlessly litter the list with this kind of stuff.  Not trying to pick on
you, Kirk, but this is far from the first similar post...  read the
thread, this is not a potential weapon system.

Dale
PICList Admin
--
"Curiosity is the very basis of education and if you tell me that
curiosity killed the cat, I say only the cat died nobly."
         - Arnold Edinborough


On Mon, 17 Jun 2002, WASSON, KIRK D wrote:

> We should not be responding to requests for information on Cruise Controls.
> Folks interested in cruise controls can get a response from: http://www.fbi.gov/
> Keep America safe, Kirk

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@111325 by Olin Lathrop

face picon face
> There a lot of real smart folks on this board. I have received great PIC
information.
> We should not be responding to requests for information on Cruise
Controls.
> Folks interested in cruise controls can get a response from:
http://www.fbi.gov/
> Keep America safe, Kirk

This is off the deep end.

There are many ordinary everyday things that in the right circumstances
could be used as weapons.  A prop pitch controll isn't even high on that
list.  We do need to be a bit more vigillant and ask a few more questions
than we would have a year ago, but we also need to proceed in as normal a
manner as possible.  Do you want to ban alarm clocks because they could be
used to trigger a detonator?  Do you want to ban diesel fuel and fertilizer
because they can used to make an explosive?  We could ban lots of stuff, and
determined terrorist would still get their hands on it.  But they wouldn't
need to because they would have already succeeded by curtailing many
legitimate activities.  The main objective of terrorists is to scare us and
to keep us from doing what we would have normally done.  Let's not allow
them to win.


*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\06\17@150614 by John Dammeyer

flavicon
face
First of all congrats to Tony.  It's fun up there.  Good description by
Dave King on props.

I'll add my two cents here since I just took my family flying on Sunday
in a low wing 4 seater with a 160HP engine.  Climb rate was a dismal
average 450 feet per minute so it took 10 minutes to get to 5500 ft
crossing the Strait of Georgia from Victoria to Vancouver.  Altitude is
your friend when crossing large bodies of cold water.  ;-)

Dave is right.  The props on the small trainers and rentals are designed
to prevent Engine damage and the best compromise with lowest price.
Constant Speed Propellers are expensive.  But with the newer high
density self lubricating plastics and composite materials for propellers
you are starting to see an increase in the use of adjustable pitch units
out there.  As usual,  the Experimental Category is paving the way.

So why have adjustable Pitch?  It's like the truck and holiday trailer
gearing down for hills.  At some grades your rig will have the throttle
wide open (WOT)and be turning maximum RPM with the engine generating
maximum power and it's that power gives you the increase in altitude at
a particular rate.  In aircraft it's called Feet per Minute (fpm).

The propeller spec'd for the General Aviation aircraft is usually sized
to the engine so that WOT at level flight doesn't overspeed the engine
which keeps renters and students from hurting themselves or the
airframe.  Once the aircraft is put into a climb attitude, airspeed and
engine RPM drop.  Like a Motorhome,  try going up that long steep
mountain hill in 5th gear.  Eventually as the vehicle slows down the
engine stalls.

Ideally you'd like to be using 100% power (high manifold pressure) at
Maximum RPM to get the greatest climb rate in fpm.  The propeller fine
pitched for that would create a very slow cruise speed and could easily
be oversped in level flight.  So at level flight,  a coarse pitch prop
which runs at max RPM and WOT gives the greatest cruise speed.

The controller that Jinx pointed to on the WEB for this propeller has
several settings including climb and cruise.  A pilot simply presses the
switch and the prop motor moves a leadscrew which pulls a nut that
twists the blades.

The cruise control Jinx refers to is the constant speed propeller
algorithm that lets the pilot set the throttle to the percent of power
he wishes via manifold pressure and the propeller controller then
adjusts to maintain a preset engine RPM.  A fine pitch setting so that
maximum RPM and therefore maximum power during a climb means the climb
rate is increased over a fixed pitch prop.

My trip to the mainland couldn't be done with full tanks because with my
family on board we would have been too heavy.  If the distance had been
greater the fuel consumption would have been a big issue.  Knowing that
I burn 6 gallons per hour  (36 pounds of fuel per hour) means that I
want to run the engine as efficiently as possible at the fastest ground
speed possible to reach my destination with reserve fuel in the tanks.
A constant speed prop would get me up to altitude faster, and then let
me cruise at a faster speed all with predictable fuel consumption.

Now as an aside on automobile conversions for aircraft.  The Honda VTEC
1.6L produces its torque over a much wider range than an aircooled
aircraft engine.  It turns a higher RPM and is more fuel efficient.
Turns out piston speed is also slower than the longer stroke aircraft
engines so they wear more slowly.  The water cooling means the engine
runs with tighter tolerances which again translates into more power.
With a reduction drive a Honda 125HP engine will produce considerably
more torque at 1800 propeller RPM than a 125HP aircraft engine turning
1800RPM.  That allows a coarser pitch on the propeller and that
translates into faster cruise with lower fuel consumption and yet at
2700 propeller RPM both engines produce the same power for identical
climb rates.  The Honda still uses less fuel because the engine is
turning 6500RPM with a volumetric efficiency approaching 97% while the
aircraft engine needs extra fuel for cooling the exhaust valve and
cylinder so runs a much lower VE and higher fuel consumption.

Hope that all makes sense.  I've spent a lot of Dyno time and Adjustable
prop time on the Honda Engine Controller (Multi-port Fuel Injection and
CD Ignition) but sometimes it's difficult to explain all this in a few
short paragraphs.

Cheers,

John Dammeyer



Wireless CAN with the CANRF module.
www.autoartisans.com/documents/canrf_prod_announcement.pdf
Automation Artisans Inc.
Ph. 1 250 544 4950


> {Original Message removed}

2002\06\17@192439 by m_imsic

flavicon
face
Kirk,

Lets not throw the baby out with the bath water!  If a terrorist wants
to buy a UAV he can do so for less than $20K.  So why would he waste his
time trying to develop something which may or may not work?  For
terrorists, money is not an issue, time is.  For the hobbyist time is
not an issue, money is.

Michael



> {Original Message removed}

2002\06\18@035259 by Alan B. Pearce

face picon face
That looks a pretty good explanation of the reasons for a constant speed
prop John. Thanks for the insight.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\06\19@133329 by Peter L. Peres

picon face
On Mon, 17 Jun 2002, Jinx wrote:

>> I assume this is a one seater yes ? ;-( Or else Mr. X might be
>> over-insured. If Mr. X says it is not difficult then it must be easy.
>
>That example was a four-seater. During testing Mr X presumably
>just takes people he doesn't like as passengers

He must really hate himself badly ;-)

Peter

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email KILLspamlistservspamBeGonespammitvma.mit.edu with SET PICList DIGEST in the body


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...