Playing dumb sometimes has it's advantages.... but I have to admit that the
Slug's comment was a memorized topic I used to teach....
Flying Helicopters is about like hanging out in a million parts flying
loose formation. when your out there beating the air into submission you
really need to know and understand the effects of Density Altitude and how
that Plays on your performance Planning data....
Each day before we flew we were required to figure out what the Performance
criteria for the day was going to be.... and often in my early days of
flying these things... we didn't have enough Power to carry two folks and a
pack of gum... so it's real performance was an issue.....
Trust me when I say the hotter it gets the Less performance you have....
the Rotor is dealing with less dense air..... and the amount of power
required to spin that BIG fan upstairs was increased as the Fan was LESS
efficient..... and required more Pitch in the blade to create the same
amount of lift....
Hence it's my point that we have to evaluate which side of the equation
your car falls under..... look at my junk .... it's a brick....
aerodynamically and requires a bunch of HP to push..... the thicker the air
I have to push through the higher the HP requirement....... BUT if I run in
the Heat of the day.... the Density of that air is much Much less then it
is in the morning and the resistance to that air is again lower.....
requiring LESS power in the Heat of the day to push it down the course...at
any given speed.
Now if your Not running in the 200mph range maybe none of this is an issue
to you and the amount of Power required to run 125mph is a bigger factor
then my car.... who knows.....
Keith...( and if you think that Thing ain't called a BIG FAN.... wait till
it comes off and watch the pilot sweat!!! )
----------
> From: John Beckett <landspeedracer@email.msn.com>
> To: DrMayf <drmayf@teknett.com>; kturk@ala.net; Dick J
<lsr_man@yahoo.com>; Want1937hd@aol.com; edvs@uswest.net
> Cc: land-speed@autox.team.net
> Subject: Air Density
> Date: Wednesday, June 27, 2001 2:56 PM
>
> I can tell you about my air density situation trying to get a 747 off a
> short runway in Cairo in the middle of summer. Long story, but sucking
the
> landing gear up at the end of the runway was a little un-nerving.
> Hot, dry air is considerably less dense. And at the speeds were running
at
> Bonneville it makes a difference.
>
> John B
> ----- Original Message -----
> From: "DrMayf" <drmayf@teknett.com>
> To: <kturk@ala.net>; "Dick J" <lsr_man@yahoo.com>; <Want1937hd@aol.com>;
> <edvs@uswest.net>
> Cc: <land-speed@autox.team.net>
> Sent: Wednesday, June 27, 2001 1:28 PM
> Subject: Re: Slugs
>
>
> > Don't know squat about salt wetness. But if air is denser then it takes
a
> > linear amount of horsepower to overcome the increased drag caused by
it.
> Hot
> > air is less dense, reduces lift and drag. Also hot air decreases HP.
But
> for
> > those on juice or pressurized and intercooled, then makes not much
> > difference. So if those conditions are met, run at the hottest part of
the
> > day. For normal aspirated run at mid morning.
> >
> > And Keith, why does an educated college dude like yourself pretend to
be
> > dumb? You went to Emory Ridel or somewhere didn't you?
> >
> > mayf, the rednecked, very ignorant, desert rat, just ask anyone!
> >
> > >Subject: Re: Slugs
> >
> >
> > >
> > > Okay let me see..... Air density is a critical factor in determining
> > > Drag... >
> > > We have talked about this Many times on the list.... Dave Dahlgren
and I
> > > were chatting about it yesterday on the phone.... and we found
several
> > > factors besides air which might attribute the Morning Passes to being
> > > slower then the afternoon passes. I'll pitch a couple of theory's
out
> > and
> > > let Mayf give us his hypothesis on them ... ( someday I'll learn what
> that
> > > word means.... just dont' teach me now I like being ignorant )
> > >
> > > 1. The Salt is wetter in the morning then it is in the afternoon.?
( I
> > > think this is true.... any decenters?
> > >
> > > a. Wet salt provides worse traction
> > > b. Wet salt increases Rolling resistance
> > >
> > > 2. The air is denser in the morning.
> > >
> > > a. Dense air increases the drag because there are more slugs per
mass
> > > volume of air.
> > > b. Dense air makes more Hp but not enough to over come the increased
> > > drag associated with the dense air.
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