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Posted

Since the Mustang does not have an artificial horizon, how do I know how many degrees my nose is above or below the horizon? There is something like a poor man's version of an artificial horizon in the P51D, but it doesn't seem to have a scale for nose inclination...

 

When landing, how do I convince myself that I am on the 3-degree glide path down to the runway?

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Intel Core I7 4820K @4.3 GHz, Asus P9X79 motherboard, 16 GB RAM @ 933 MHz, NVidia GTX 1070 with 8 GB VRAM, Windows 10 Pro

Posted (edited)

Use your vertical velocity indicator to obtain sink rate, and IAS to approximate ground speed. From there it's trig, but I would just do it using the seat-of-your-eyeballs method.

 

If you really want to do it by the numbers, at 125 mph GS you're looking at 576 ft/min sink rate to maintain a 3 degree glide-slope.

 

Equation:

 

tan(3 deg) = sink rate / speed

 

Make sure to convert from mph to ft/min.

 

As for knowing proper nose angle for landing, remember what it looks like prior to take off. You want to touch down (after flare) at the same nose angle.

Edited by flightace37

- WH_Mouse

Posted

I always use ground speed X 5, but of course I always have GS in knots, so you'd have to switch to that from mph (damn imperial units!)

Posted
Use your vertical velocity indicator to obtain sink rate, and IAS to approximate ground speed. From there it's trig, but I would just do it using the seat-of-your-eyeballs method.

 

If you really want to do it by the numbers, at 125 mph GS you're looking at 576 ft/min sink rate to maintain a 3 degree glide-slope.

 

Equation:

 

tan(3 deg) = sink rate / speed

 

Make sure to convert from mph to ft/min.

 

As for knowing proper nose angle for landing, remember what it looks like prior to take off. You want to touch down (after flare) at the same nose angle.

 

We would appreciate an explanatory video of your method. :smartass:

AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

 

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.

Posted

You can still use it like a modern Attitude indicator. The technique is to use "Bar widths" to replace the modern Degree values. The technique was to determine how many "Horizon Bar" widths above or below the horizon is required for a specific flight phase. Then use these as a datum and adjust accordingly to achieve precise performance.

 

The thickness of the Horizon bar is "1 Bar Width".

 

POWER + ATTITUDE = PERFORMANCE.

 

The Bar width technique is described well in some of the older WWII era Instrument flight training manuals.

Posted

In mph for a 3 degree glide slope, it works out to around ground speed x 4.6 to get your feet per minute sink rate. Just take GS x 5 and take a little off, but remember that the trig is where you get those easy-peasy multipliers from. ;)

 

Mouse's infamous by-the-seat-of-your-eyeballs method is classified. Sorry!

 

Actually, I just fly the numbers like you're supposed to. Once you're close to on-speed and in the right kitchen sink (sink rate), you look around the nose and adjust your aiming point as necessary, using the far end of the runway as a guide once you can't see the actual threshold anymore. If you hit all the numbers exactly at the end of your base turn (speed, sink, altitude, distance), you can literally just ride them all the way to touch down, chopping power and flaring right before you reach the ground.

 

I don't have the official numbers on hand for the P-51, other than the IAS, but we can compute the final approach altitude at 1 mile using the glide slope equation.

 

tan(3 deg) = altitude / distance

 

This works out to 276 ft AGL, 1 statute mile (5280 ft) from touch down. Use 300 ft for a little safety. I suspect that is the standard figure, given that the A-10C approach pattern uses 300 ft at 1 mile as well.

 

 

Ivan definitely has it right that the attitude indicator (whatever it's called in WW2 terms) can be used if you define "bar width" units, but I question its utility. I've frequently had it go out of whack, after which I re-center it. Given that level is defined by the aircraft's pitch and roll at the time of centering, you won't have a true representation of your pitch after flying around for a little while.

 

Instead of locking yourself to a specific nose angle when landing, you should be flying IAS and sink rate, which are the two components that geometrically define your glide slope. The nose will be pitched at whatever angle it needs to be to set those two figures, in combination with your throttle. Affect airspeed by adjusting pitch as necessary, and affect sink rate by adjusting power.

- WH_Mouse

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