[jhb_airlines] Re: Performance Query

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Sat, 20 Aug 2005 06:52:04 +0100

Ta for that Mike - I actually got CalcV40d.exe - a nice simple DOS prog.

It was interesting working through a couple of simple examples as it was all
to easy to forget the RPN logic and fall into a trap. I was all right with
(3x2)+1 as 1 2 3 * + but it took me a while to twig why 1 2 3 * - gave -5
instead of 5 (because it was 1-6 rather than 6-1). In fact you can use 2 3 *
1 - or 1 2 3 x r - here.

Which all gets me back to Gerry's original line of (A:TOTAL WEIGHT,pound)
(L:VSPEED_LOW_WEIGHT,number) - * + because it doesn't make sense. Once the
minus has executed the stack is clear so the * + don't seem to do anything.
Not in the calculators that is - so I hope the RPN used in FS2004 isn't a
tweaked version.

The work is not in vain as I need to understand this stuff for a couple of
my own troublesome gauges.

bones

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Brook
Sent: 19 August 2005 19:13
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: Performance Query


More at http://www.hpmuseum.org/rpn.htm and Calc98 seems to be configurable
to use RPN http://www.calculator.org/download.html  I'm going for the malt
option...

M.

> -----Original Message-----
> From: jhb_airlines-bounce@xxxxxxxxxxxxx
> [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx]On Behalf Of Bones
> Sent: Friday, August 19, 2005 6:56 PM
> To: jhb_airlines@xxxxxxxxxxxxx
> Subject: [jhb_airlines] Re: Performance Query
>
>
> I can understand the example on that page as it confirms the stack is
> reversed but the operands not.
>
> 3 2 1 + x is logically (1+2)x3 =9 and 1 2 3 x + is (3x2)+1 =7. But
> then I wonder about (-3x2)+1..  1 2 3 - x + ??
>
> But (A:TOTAL WEIGHT,pound) (L:VSPEED_LOW_WEIGHT,number) - * + ???  Two
> values in the stack but three operands? Is one of the stack items a
> negative value and it's giving Total Weight x (-VSpeed)? It seems
> logical but then we
> get to a second problem of two brackets in the line.
>
> Gerry needs (X/1000) x (-Y/1000) and this requires two sub sets to be
> worked out before multiplication. I'll have to read up a bit more to
> see how 1000 Y
> - / + (or is it just 1000 Y / - ?) is calculated and then
> returned to the
> top of the stack to await 1000 X / + ..
>
> Hateful stuff. I wonder if there is an RPM calculator online?
>
> bones
>
>
> -----Original Message-----
> From: jhb_airlines-bounce@xxxxxxxxxxxxx
> [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Brook
> Sent: 19 August 2005 12:54
> To: jhb_airlines@xxxxxxxxxxxxx
> Subject: [jhb_airlines] Re: Performance Query
>
>
> Gerry -
>
> My knowledge of RPN goes back to the dim and distant days of early HP
> scientific calculators (late 1960's) so is VERY hazy <g>.  Maybe the
> following site would help you in getting the logic sorted out:
> http://www.calculator.org/rpn.html
>
> MikeB
>
> > -----Original Message-----
> > From: jhb_airlines-bounce@xxxxxxxxxxxxx
> > [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx]On Behalf Of
> Gerry Winskill
> > Sent: Thursday, August 18, 2005 6:10 PM
> > To: jhb_airlines@xxxxxxxxxxxxx
> > Subject: [jhb_airlines] Re: Performance Query
> >
> >
> > Bones,
> > It struck me I might be able to get around the comma problem, when
> > using both the Vspeed gauge and your weight gauge. In the case of
> > Vspeed, a version has to be created for each individual
> > aircraft, by editing the source file and inserting the high and low
> > takeoff weights to be covered, together with their Vnumbers
> > at the flap
> > settings permitted for takeoff config. No problem there.
> > It considers actual Ramp Weight and signifies an over load, when
> > present. That's the current problem with the Q400. The
> > warning could be
> > ignored but the calculated V numbers are daft, having been
> > based on the
> > comma'd weight. Now, if I include a factor of 1000 in the
> > calculation,
> > that might restore sanity.
> >
> > The existing line is
> > (A:TOTAL WEIGHT,pound) (L:VSPEED_LOW_WEIGHT,number) - * +
> >
> > If I want to multiply the TOTAL WEIGHT by 1000, what's the syntax?
> >
> > Gerry Winskill
> > gwinsk@xxxxxxx
> >
> >
> > Gerry Winskill wrote:
> >
> > > I've spent the day, well most of it, modifying Rob
> > Barendregt's Vspeed
> > > gauge, to suit my normal CA aircraft. Once his instructions are
> > > decyphered it's not too difficult. The sticking point at
> the moment
> > > is that next in the queue
> > is the Q400
> > > and I haven't any real life data for it.
> > > What I'm looking for is the Vnumber data for lowest and
> > highest take
> > > off weights, at the normal flap settings used. The
> > Bombardier website
> > > doesn't have it. Anyone able to suggest a site where I
> > might find it?
> > >
> > > The gauge is useful in that it also provides the speed
> > calls, filling
> > > the empty second seat gap.
> > >
> > > Gerry Winskill
> > > gwinsk@xxxxxxx
> > >
> > >
> > >
> > >
> >
> >
>
>
>
>
>
>





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