On Sun, 27 Dec 2015 23:46:43 +0000, Phil W Lee
wrote:

John B. considered Sun, 27 Dec 2015 12:39:16
+0700 the perfect time to write:

On Sat, 26 Dec 2015 18:02:59 +0000, Phil W Lee
wrote:

John B. considered Fri, 25 Dec 2015 08:28:15
+0700 the perfect time to write:

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.

But you know how fast you are flying, and in what direction, so just
making occasional fixes allows you to correct for the difference
between forecast winds aloft and actual - which is all you need.
Unless you are skirting very close to controlled or restricted
airspace, you only need to know where you are to within a couple of
miles, at least while you are at altitude and over featureless terrain
or ocean.

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.

Either of which can be damaged or destroyed by adverse weather.
It's a bit like self-steering gear. Nice to have, but a good sailor
should know their boat well enough to be able to balance it on most
points of sailing, or if it is badly balanced, at least know which
points of sailing it will or won't hold without manual steering and
sheet management. Heck, even roller reefing (or more particularly,
the gooseneck it uses between boom and mast) is a weakness that a good
sailor should be able to manage without if necessary.


Frankly, I hear that a lot, from shore bound folks, but in reality
when you go to sea there are a lot of things that can't be repaired
without outside help. I've never seen a sailing yacht with more then
one auxiliary motor and the cry, "Oh! I'll just sail it." is not
really a solution, in some cases when the engine fails.

That depends partly on how far you are going and how well you can sail
it, maybe?

Not really. It depends very much on where you are. My understanding is
that in the British Isles wind is practically an every day occurrence
but in the monsoon areas it may hardly blow at all for months out of
the year.

Sir Robin Knox-Johnston never once used his engine on his ketch
Suhaili all the way from Falmouth to Falmouth, 313 days at sea, 30,123
nautical miles. When he tried to turn it over fairly early in the
voyage (to use as an auxiliary battery charger), he discovered it had
seized.

Yup, and I mention below about the guy that takes almost a month to
drift something less then 100 miles.

His self-steering broke before he was half-way, and his gooseneck
after only a third. He ended up doing without the former altogether,
but kept repairing the latter, although of course there were lengthy
periods while it was being repaired when he was managing without,
usually in the worst weather conditions.

One can only speculate. I know probably 20 people who have made a
circumnavigation and neither their wind vane nor their gooseneck
broke.

I knew a bloke
who's transmission failed about 10 miles out from Phi-Phi Island, in
Thailand, when he was trying to get to Langkawi in Malaysia - about a
hundred miles - during the S.W. monsoon when there are very light to
no winds in that region. It took him nearly two weeks and much of the
time he was drifting with the tide and anchoring when the tide turned.

That's a situation where he should have turned back.
He could have got it fixed and still arrived at Langkawi sooner than
he did, and far more safely.

How?

The VL cargo ships have only a single engine and propeller.

And thrusters, which although they are intended for use when mooring,
can also be used to keep the ship from ending up broadside to the seas
if the prop or shaft are damaged.

The point is that there is little forward motion without the motor
driving the propeller and I doubt that one can cross the pacific using
only the bow and stern thrusters :-)


If the gooseneck breaks, depending largely on the type of rig, the
boat could probably be sailed with the main loose footed as the boom
actually only serves to make the sail easier to handle - single sheet
- and allows for more control of sail shape - out haul.

Or you can lash the boom to the mast, depending on the rig and the
circumstances.

Self steering :-) ever try hand steering a boat for days and days? I
have and it is not really something that I care to repeat.

RKJ reckoned he spent more time sewing than steering, but Suhaili was
a very well balanced boat.

As for "balanced without manual steering", very few sloops - probably
the most common yacht - can be sailed that way. And saying "which
points of sailing it will or won't hold without manual steering" is
even worse. The N.E. Monsoon will blow for the next 5 months and I
want to, have to, go north. No sloop I've seen will sail to windward
hands off.

Well, that's an inevitable consequence of having only one mast and two
sails - you have less choice of balance available. And having such
relatively large sails makes them more difficult to handle if things
are going pear-shaped.


I don't believe you have ever sailed, or at least not much :-) One
doesn't have large sails when things are going pear shaped.

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 :-)

All the large and medium sized aircraft are now turbine, yes.
They tend to be more expensive initially, but with much lower running
costs, so if you keep them long and do lots of hours, the total cost
of ownership is lower.


They also produce far more power from a smaller, lighter package :-)

Well, yes - that's partly what makes the running cost lower.

Some of the H-34's (I think it was) were converted from Recip engines
to turbo and had a rather surprising amount of ballast added to
compensate for the reduced power plant weight.

Yes, depending on how the overall weight and balance is originally,
that can be a problem with conversions.

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.

It's more individual cylinder size, as that's what you are compressing
in one go in order to start it. And of course, if it's not magneto
ignition, the minimum speed at which a magneto will give a spark is
irrelevant, as you have a battery to do that.

Well, the 500cc single engine has a 30.5 cubic inch cylinder while the
80 cubic inch Harley twin had a 40 cubic inch cylinder, and, to the
best of my knowledge the Harley "80" was made only with a manual kick
starter :-)

But not magneto, so no minimum speed to get it to spark, which means
you can just use low gearing on the kickstarter.
And the Harley 80 was a pretty soft state of tune anyway, at least
compared to the sportier of the 500 singles.

Well "soft" maybe. It was a lot of years ago now but my 80 cu. inch
bike (actually bored and stroked to 92 cu.in.) was, at the time,
unbeaten in quarter mile drag racing, in the Miami Florida area. Be
either 2 or 4 wheels :-)



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.

I never owned a "big Bike" that had a "rev counter"

So not all that highly tuned then?
More highly tuned engines tend to need them, as one result of tuning
them to give a higher output is to narrow the engine speed range over
which it's produced.

But why bother? Just built a bigger motor :-)

Come to think of it, I've only ever owned one 4 stroke motorcycle
without a rev counter, and that was a 50cc moped!


snipped

That only works in VFR below the clouds.

Piper Cubs were only flown VFR!!!!

Of course.
You can't fly IFR without instruments and a radio.
--
cheers,

John B.