How is TOT supposed to work?

If I enter a time-on-target into the HSI, it always gives me a ludicrously low required ground speed, usually <20kts. This happens even if my target waypoint is 50 miles away and the TOT is five minutes from now. Can someone explain what I'm doing wrong?

Also, I assume entering a GSPD overrides the TOT calculator. Is that how it works?

Watch the last few mins of Wags video here.

The only thing that seems wrong- is that the carret will actually be to the RIGHT if you are late/slow and left if you are early/fast.

Had some trouble myself, but follow this to the letter, and as long as you are within reason to hit the TOT, it should work fine.

Zulu time is also required

The thing to remember is it gives you required airspeed to the waypoint before the target, and you go your input ground speed from there to the target.

Also if you are flying the waypoints, when flying over the selected wypt,

you have to select the next wypt (unless wypt set to auto)

I think,

Seems t be working Great, for the DEVs

Coming Along Nicely People

I'm a bit confused...I watched the video what I don't understand is it says you need to input both ground speed and select TOT for the selected WP. I would think you should only need to input TOT for the selected WP...not both. Then it would indicate the GS necessary.

Say you have 6 waypoints, #6 is the TGT.

TOT input is the time you will arrive at waypoint 6.

GS input is speed from waypoint 5 to waypoint 6.

GS REQ output is the required ground speed from your current position to waypoint 5, in order to arrive at waypoint 6, at TOT, at GS.

Say you have 6 waypoints, #6 is the TGT.

TOT input is the time you will arrive at waypoint 6.

GS input is speed from waypoint 5 to waypoint 6.

 

GS REQ output is the required ground speed from your current position to waypoint 5, in order to arrive at waypoint 6, at TOT, at GS.

Thanks for the feedback... say I create only 1 waypoint in a 2nd sequence of waypoints and want to set a Time on Target for that 1 waypoint? Shouldn't I be able to just select that waypoint and key in a desired TOT and have the computer indicate the required speed necessary?

Why do I have to calculate a ground speed to a previous waypoint first?

Also the waypoint countdown timer tells you when you will arrive at any waypoint at your current speed.

As far I can tell, you can't.

You have to have a preceding waypoint and Fixed GS from there to the target.

There's probably some technical reason it uses a fixed GS to the TGT, but, not knowing precisely what that reason is, I'll just say "Because Navy."

As far I can tell, you can't.

You have to have a preceding waypoint and Fixed GS from there to the target.

There's probably some technical reason it uses a fixed GS to the TGT, but, not knowing precisely what that reason is, I'll just say "Because Navy."

LOL....thanks, I'll use the countdown timer on the HSI.

You can use TOT without GS but you need to manage airspeed yourself so you dont end up too slow on the final leg.'Thats why its better to use it with GS

You can use TOT without GS but you need to manage airspeed yourself so you dont end up too slow on the final leg.'Thats why its better to use it with GS

Are you're saying if I only put in the time on target without the GS it will need me to calculate my speed enroute.

TOT, time on target which is based on when you want to be there, the speed will determine that. I don't want to have to do the math to figure what the speed needs to be, let the computer do the figuring for me. This is already calculated on the HSI waypoint info box so it should be auto configured in TOT.

As far I can tell, you can't.

You have to have a preceding waypoint and Fixed GS from there to the target.

There's probably some technical reason it uses a fixed GS to the TGT, but, not knowing precisely what that reason is, I'll just say "Because Navy."

GS should be calculated automatically based on TOT. I don't understand the need to set a GS to the previous WP, I can certainly understand the need for a specific GS to the target but that's what the onboard computer should be giving you not vice versa.

im guessing, but I believe that for tactical reasons, you want the ability to determine your own groundspeed over the target. otherwise, the computer might tell you that you need to be doing 250kts for example. That is too slow for a hostile environment. So, make a waypoint outside the hot zone, and tell the computer the groundspeed you want to be at so you have good energy, say 500 kts. It will then get you to the point prior to the target waypoint at the right time so you can then accelerate to your desired safe high energy state AND arrive at the target on time.

im guessing, but I believe that for tactical reasons, you want the ability to determine your own groundspeed over the target. otherwise, the computer might tell you that you need to be doing 250kts for example. That is too slow for a hostile environment. So, make a waypoint outside the hot zone, and tell the computer the groundspeed you want to be at so you have good energy, say 500 kts. It will then get you to the point prior to the target waypoint at the right time so you can then accelerate to your desired safe high energy state AND arrive at the target on time.

The A10C only does a simple Distance/Time = Speed calculation to give you an average speed IIRC, in which case yes you'd have to do as described e.g. if you need to be at a target in 30mins (0.5 of an hour) and you're 150nm away, it'll tell you to fly at 150/0.5 = 300kts. If that's too slow, you have to work something out yourself.

You don't need to do that in the Hornet though, because you can enter a required GS into the UFC when entering TOT data and it'll compensate for you. e.g. same scenario as above but you require 500kts at the target, it'll direct you to fly slower than 300kts at first, so you can fly faster later on and arrive at the same time.

The big thing that got me was ZULU time. In the black sea its 4hrs off.

so you start at 08:00:00 and you set your TOT to 08:15:00 thinking you are going to reach the TOT at 08:15:00 well you are all ready 4hrs off.

You need to set ZULU for the TOT. Look at your HUD or fuel panel and hit zone to bring up Zulu. Then you know what the real TOT should be.

Also Ground Speed is not needed to be set. BUT as others have said if you DO NOT set ground speed the the TOT will be divided by the number of waypoints and the computer will tell the constant speed for the TOT.

If you set a Ground Speed you can have the RUN IN faster. IE: 400 Ground Speed at Waypoint 2. (With 3 being tgt).

The computer will figure out how fast you need to fly to hit waypoint 2 so you can Increase speed to 400 for you attack run.

it should would look like this. (Numbers are made up fyi)

No ground speed you go 300 for all waypoints to hit your TOT.

With ground speed you go 250 until waypoint 2 at waypoint to it would jump to the 400 you set so you are engaging the target at a faster speed.

But both ways you hit TOT the same.

Question for clarification:

Does TOT require a waypoint between your current position and the target waypoint to work?

The last couple of days I have been trying TOT per the procedure in Wag's video, but the REQD GS ignores my desired TOT, with the HUD caret simply showing me how to get to my desired GS, resulting in me flying my desired GS but arriving at the target 10 minutes early.