Thread: O/T: knots
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Old December 25th 15, 02:28 AM posted to rec.bicycles.misc
John B.[_6_]
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Default O/T: knots

rOn Thu, 24 Dec 2015 20:47:53 +0000, Phil W Lee
wrote:

John B. considered Wed, 23 Dec 2015 09:14:08
+0700 the perfect time to write:

A great deal of redundancy snipped


Well, a military aircraft should anticipate the possibility of the GPS
constellation being knocked out.


But there is no necessity. You said, above, that you could use radio
beacons and other radio stations to navigate by.


Or INS, or celestial navigation.


Are you serious? Celestial navigation? In an airplane? It probably
takes 10 to 15 minutes to actually make a minimum of two star sights
and work out a position. Which is possibly accurate to, say a 2 mile
radius. In an aircraft flying at, again say, 500 MPH (Boeing 747
cruise M-0.85)?

In 10 minutes the airplane travels ~80 miles while you are fanatically
making a series of fixes. All accurate to a location 75 miles behind
you.

More snipped
But more realistically, most yachtsmen, on offshore voyages, carry at
least two GPS receivers, and sometimes even more. I've even got a
wrist watch device that includes GPS. Some boats carry "chart
plotters" and don't use paper charts at all any more.

What kind of battery life does your wrist GPS have?

A rechargeable one :-)

Which can be re-charged from either the solar panel or the wind
generator.

and yet more snipped

As for Edwards AFB, they have a lot of odds and ends of aircraft
there. Some, and I suspect the Slingsby Firefly, as there were a
couple of crashes with that aircraft, that Edwards did some flight
testing to see if the aircraft would recover from one particular
maneuver. The aircraft passed the tests I believe :-)

Yes, the aircraft didn't have a problem - the crashes were all put
down to pilot error. But I don't know why they retained that
aircraft, let alone the AN-2.


At least when I was stationed there were a lot of old aircraft
scattered around. At one time - maybe in the very late 1960's - I saw
what may have been a Hiller X-18, which flew its last flight in 1961.
And of course the B-52A (only 3 ever built) that had carried the X
aircraft :-)


But, you get more revs from the kick starter on a bike than the
starter on a large aircraft engine.

On large aircraft engines, maybe, but I've not had much to do with
them. I do know that motorcycle kickstarters are very variable,
partly depending on size. Big singles (500+cc) are particularly slow.


Really, I had a Harley 80 cu. inch, flat head, and had no problem kick
starting it. I never owned a 500 c.c. bike but I did ride a mate's 500
c.c Norton single and it started easily. (In fact, the first
motorcycle I saw with an electric starter, I wondered about whether it
was intended for the ladies :-)

Did your Harley have magneto ignition?


Nope, but your remark about the "big" 500 cc bikes I assumed that you
were referring to engine size.

The Norton's (and similar BSAs, Matchless, etc) difficulty in starting
was almost directly determined by the state of tune - the higher the
power it was tuned for, the more difficult it was to start.
But the point (pardon the pun) is how fast the engine needs to spin to
give a useful spark. I'll bet that it was too slow to even register
on the rev counter until the thing was running. It has been on every
four stroke I've ever owned with a kickstarter.


Yes, likely due to advanced Ignition timing. I once helped to push
start a Norton 500 cc "feather bed" racing bike at the Daytona Beach
races that the rider said was impossible to kick start.

Come now. I flew with my father when I was just a lad, in a Piper J-3
and it didn't have any vacuum instruments in it.

Only because it only had pitot/static instruments and a turn & slip
indicator!


No turn and slip indicator. An altimeter, magnetic compass and air
speed was all the flight instruments it had.

Yeah, I knew they didn't have a lot.
The continued existence of aircraft like that is one reason why it's
still legal to operate NORDO (outside controlled airspace) - because
you can't fit a radio to something without an electrical system.
Of course, the same is true of some yachts, and the conditions under
which they can operate is potentially far more hostile to electrical
systems, both in severity and duration.


The preferred navigation method was to follow the railroads :-)

By the way, there is a research paper titled "Vision-Based
Road-Following Using a Small Autonomous Aircraft" done at the AINS
Center for Collaborative Control of Unmanned Vehicles, University of
California, Berkeley, which apparently is dated 2003, which describes
the method :-)
--
cheers,

John B.

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