VIPER HUD display question

[flankerjun]

When i try landing VIPER，I find that the flight path marker，E symbol，and the ILS cross(localizer and glideslope bars), are always at the very bottom of the HUD，this make it difficult to aim at the right position of the runway.

i have the speed of the 180 knot, 2.5 mile from the airport and have an altitude of 500FT.

i'm quite skillful to land a hornet,and the symbols are at the lower middle of HUD，that’s OK.

So i don't know why the viper is different from Hornet

 

223750_20191015200047_1 by fang jun, 於 Flickr

[razo+r]

Move the seat/head up, cause it looks like your view is too low.

[Lace]

Move the seat/head up, cause it looks like your view is too low.

 

 

Yep, stop slouching.

[Bouli306]

You are on a steep approach of about 5 degrees.. Normal is around 2,5 to 3

[Dee-Jay]

Hi!

 

You are on a steep approach of about 5 degrees.. Normal is around 2,5 to 3

 

100%

 

FPM has to be within the brackets (to get the right AOA), but the FPM must also be on the runway threshold (aim-point) AND and the correct -2.5° -3° cue (path/glide).

 

The screenshot on post #1 shows a descent path of -6° or -7° which is almost suicidal. (F-16 don't have the same landing gear than an Hornet made to land on carrier) ... has to be -2.5 to -3°.

 

Regards.

Edited November 16, 2019 by Dee-Jay

[flankerjun]

Hi!

 

 

 

100%

 

FPM has to be within the brackets (to get the right AOA), but the FPM must also be on the runway threshold (aim-point) AND and the correct -2.5° -3° cue (path/glide).

 

The screenshot on post #1 shows a descent path of -6° or -7° which is almost suicidal. (F-16 don't have the same landing gear than an Hornet made to land on carrier) ... has to be -2.5 to -3°.

 

Regards.

 

OK，THANKS A LOT，i have revise my path， it is much better，but i have to maintain the speed above 170KNOT，or the glide path will become 5° even more.

 

223750_20191117121104_1 by fang jun, 於 Flickr

[Tom Kazansky]

The 2nd screenshot shows a better approach but there is still space for a bit nose up and a bit less throttle.

 

 

With the Viper it is enough to get the FPM to the top of the bracket bc you flare later and get it to the center on touch down.

[Dee-Jay]

... I have revise my path， it is much better，but i have to maintain the speed above 170KNOT ...

 

Forget about the speed per say. Focus on AoA / Bracket / Aimpoint.

 

Except on some exceptions, fighters has to be flown through AoA, not airspeed.

 

${1}

[Tom Kazansky]

Exactly. And don't forget the angle of the decent path. The viper does not stand a Hornet's rate of descent as it was mentioned here before.

 

 

If you get those points together speed is of little to none interest.

 

 

Try first to get on speed and then check your glide path angle. If it is too high, you are too high. And vice versa.

[Eldur]

Enough said basically.

 

However the speed indication can still be of value, but you'll have to rethink here. Over time, you'll get experience with how much length of runway you need to stop the jet - and that directly depends on the touchdown speed. So you could decide to go around another time and burn some fuel or drop stores in case you'd be coming in too fast at good AoA and glide slope.

[Dee-Jay]

Enough said basically.

 

However the speed indication can still be of value, but you'll have to rethink here. Over time, you'll get experience with how much length of runway you need to stop the jet - and that directly depends on the touchdown speed.

 

 

I'll have to check the chart again but as far as I remember, factor is the a/c's masse. Not speed per say (even if we can agree that both are tied).

[Cupra]

the a/c's masse. Not speed per say (even if we can agree that both are tied).

 

Exact. I also can not say the perfect speed for the model we have in DCS but in general you can calculate this way:

 

Landing speed is 134kts plus 4kts for each 1.000lbs of addtional wheight of the jet. So each 1.000lbs of fuel add 4 knots, every 500lbs of weapon, pylons or additinal parts like TGP add 2 knots…

 

If you land with 2.500lbs fuel and have 2.000lbs weapon and stations on board your landing speed will be around 152kts... 134kts for the plane and 18kts plus for fuel and loadout…

 

But if you have the charts of the jet you fly with all the informations you can also read it there.. if you want to land by speed.. (I would post it but I think all real informations newer bothers wrights basic plans are forbiden here… :music_whistling: )

 

For example. If you have an F-16 with the F100-PW-200 engine and you jet is in landing configuration.

Based on a 13° AoA at a GW of 26,000 lbs your final approach speed will be about 155KIAS, touchdown at 143KIAS...

 

 

But at the end.. stop thinking about speed, just check AoA indexer (green light), FPM and the AoA on the Basic-T at landing...

Edited November 17, 2019 by Cupra

[VDV]

OK and what indicates the AOA ot the HUD?

[razo+r]

14 minutes ago, VDV said:

OK and what indicates the AOA ot the HUD?

The "E"-Bracket shows you in a simple way the optimal AoA for Landing.

The angle between the gun cross and your FPM is also showing you your AoA.

[press]

You don't usually land with over 11000 lbs of fuel, this is one of your problems. Try with less, let's say 3000lbs of fuel and a cleaner jet (maybe with only two empty bags).

Also your 2.5 degrees line should be aligned with your FPV and with your runway aiming point (touchdown zone) while maintaining 11 degrees AoA. You are using a Hornet style landing technique which doesn't work on the Viper. The Viper glide path angle (not AoA angle) should be around 2.5 to 3 degrees max, that translates into around 500fpm of vertical speed on final approach, you have around 2000fpm which way is to much.

You're in a Viper, not in a Hornet. The Hornet technique will destroy the Viper upon touchdown.

[Aquorys]

On 11/17/2019 at 11:12 AM, Tom Kazansky said:

Exactly. And don't forget the angle of the decent path. The viper does not stand a Hornet's rate of descent as it was mentioned here before.

The approach angle doesn't really matter, because Air Force pilots flare before landing instead of crashing into the runway