Small Comet Obs...

[petermcleland]

I'm flying along at 37,000 feet in the Comet 4 bound for Pago Pago and just thought I would mention a couple of things:-

1. Cabin Altitude settles at 8250 feet so since this is above 8000 feet the Cabin Pressure item in the Climb & Cruise Quick Checklist is NOT ticked. The Required Cabin Alt. knob has no effect on this if turned down to 7000 feet as the cabin pressure can not be persuaded to go above 8.0 psi

2. Wind Direction on first page of Quick Check Lists is TRUE rather than MAG.

3. Landing Gear Pos Lights on Overhead Panel...When Greens are lit, only one of each pair of greens should be lit (not both)...There is a small rotary switch in the centre (as well as the Day/Night slide) which selects the alternate 3 green lights in the event of bulb failure.

4. 2D panel lights fail when you shut down the engines (just before the RPMs reach zero).

Enjoying my cruising DM...Thank you for a lovely aeroplane

[MALTBY D]

Thanks Peter.

Cabin Alt. I'll change the checklist tick to be a bit more lenient.
But I do wonder if the maths is out slightly. But just looking at it now, I don't understand it anymore.

Roger on the landing gear lights, I never knew about that & will change it.

I don't get any panel light failure here when shutting down the engines.
The only way that happens is if the battery isn't on, or has run flat.
It's losing Generator power when the engines go, but battery power is keeping the lights on for me.

Wind direction - It shows data for the wind using these two variables (same as all the other models)
(A:AMBIENT WIND VELOCITY,knot)
(A:AMBIENT WIND DIRECTION,degree)
I don't know how I'd get a Mag wind direction, can you explain some more on that one?

Cheers
David

[petermcleland]

Dave, the MAG wind variable is in FS9 somewhere because it is the one that displays in red at the top of the screen when you press SHFT+Z once. The one that FSNav displays at the bottom left corner of its map is TRUE (the same as yours). Naturally the Magnetic Wind is of more use in the cockpit because the only heading information in the cockpit is a magnetic compass. In high MAGVAR areas looking at a True Wind and thinking it was Magnetic could put your expected crosswind from the wrong side of the runway...I think as a general rule, printed winds are True but verbally passed winds (like from ATC) are Magnetic.

I would think that MAGVAR is in there somewhere and your A should be plus or minus MAGVAR with the rule Magnetic Variation East then MAGNETIC is LEAST, Variation West then MAGNETIC is BEST

Funny about my lights in the 2D cockpit...They fail on shutdown as the RPMs get near zero but the VC lights stay working...If I now restart the engines then the 2D panel lights will not come back on...Then I have to Cycle the L key twice to switch all lights off then on again to get my 2D panel lights back :think:

On the pressurisation, the cabin altitude should reduce if you wind it down to 7000 feet from 8000 feet and it will do that by increasing the cabin pressure...However, the cabin pressure will not exceed 8.0 psi even though the cabin pressure gauge is red lined at 8.75 psi.

[MALTBY D]

Can't find a ready made variable for it Peter, but there is a MAGVAR variable so it can be worked out.
((Ambient Wind Direction - MAGVAR) + 360 mod 360) seems to do the trick.
It's a good job I'm clever. HELP (and have access to lots of old XML code that's gone before)

Now I know that the wind direction on the Shift-Z is adjusted for Magnet Variation, it's easy to check what the value should be. Never noticed that mine was ever reading different.
Learned something new again.

I think the pressure thing may be some throw back to the 1-11. The code was pinched from that one & the limits are slightly different.
I'll have a look at it and try to understand what it's doing again.

Ta
DM

[petermcleland]

Thanks Dave...sorry for the delay in answering...I was landing at Pago Pago...Not much room to park, but I stuck it in front of the Tower :roll: Tomorrow, on the Christchurch

[Viscount Cornbank]

Hi David

I think there's a bit of code in the data icon or data card on the Britannia VA update that works out the variation as well as the crosswind component and gusts. I've got it on most of my panels now but think the Brit is the only public one. Not at home at the moment so can't check but will later. ;-)

cheers

Fraser

[Viscount Cornbank]

This is what I made;

<Element>
<Select>
<Value>(A:Ambient Wind direction,degree) (A:Magvar,degree) - (>L:Wind_Vector,number)</Value>
</Select>
</Element>
<Element>
<Select>
<Value>(A:Autopilot heading lock dir,degree) (L:Wind_Vector,number) > if{ (A:Autopilot heading lock dir,degree) (L:Wind_Vector,number) - (>L:Wind_Component,number) } els{ (L:Wind_Vector,number) (A:Autopilot heading lock dir,degree) - (>L:Wind_Component,number) }</Value>
</Select>
</Element>
<Element>
<Select>
<Value>(L:Wind_Component,number) 61 < if{ (L:Wind_Component,number) 1.5 * (A:Ambient Wind Velocity,knots) * 100 / ceil (>L:Crosswind_Component,number) } els{ (A:Ambient Wind Velocity,knots) (>L:Crosswind_Component,number) }</Value>
</Select>
</Element>
<Element>
<Select>
<Value>(A:Indicated altitude,feet) 2700 <= (A:Ambient Wind Velocity,knots) (L:Wind_Gust,number) > && if{ (A:Ambient Wind Velocity,knots) (>L:Wind_Gust,number) } els{ (A:Indicated altitude,feet) 2700 > if{ 0 (>L:Wind_Gust,number) } }</Value>
</Select>
</Element>

cheers

Fraser

[petermcleland]

DaveM,

Just an observation from the Great Bight of OZ...It would seem that pressurisation problems with the checklists only occur at FL370 (Comet 4) because your model limits the Cabin Pressure to 8.0 PSI...If you were to allow the cabin pressure to rise to 8.5 PSI (it is redlined at 8.75 PSI) then the problems would go away and the Cabin Altitude would not exceed 8000 feet. No red lines would then be infringed and the Checklists would Tick the items.

[MALTBY D]

Peter, I sent you a PM on Thursday with some fixes for you to try out.
Just looking now... It's still sat there in my out-box. :o :think:
Does that mean your in-box may already be full, or are PMs knackered?

Anyway, I think I've sorted out the cabin pressure.
Let me know if you can't get hold of that PM & I'll e-mail it to you instead.

And thanks Fraser, the Mag Var fix is working too.

Cheers
David

[petermcleland]

Thanks DaveM...The PMs are working fine...It is just the email notification that isn't. I've checked my settings and they seem correct. Anyway, I'll try out the fixes on tomorrow's flight