INU Alignment Status

I know there is a 0-second wait time for the INU to align in the current DCS implementation. When/If that time does go to more than 0-seconds, what indication will the pilot have that the INU is flight-ready?

For example, in the F-16, there is an "INU Alignment Status" indicator. Once the INU achieves a specific level, the pilot can stop the alignment process and proceed with flight.

If the Ka50 has any such indicator I haven't found it. Anybody out there know of one that I'm missing?

What do the real Ka50 pilots use? Just time delay?

Actually there is a standard INU alignment time implemented now. I believe it's around 3 minutes. This is why some people complain about the lack of airspeed indication on the HUD during take-off. The INU was not ready.

There is no indication for INU alignment. Not sure if there is any in the real bird.

Actually there is a standard INU alignment time implemented now. I believe it's around 3 minutes. This is why some people complain about the lack of airspeed indication on the HUD during take-off. The INU was not ready.

Anyways, trying to takeoff without a sufficiently aligned INU will result in your nav system being way off, in position, velocity, and attitudes. (see http://www.f-16.net/f-16_forum_viewtopic-t-634.html for one informative discussion on real-life INU alignment concerns). This, of course, would render the autopilot stupid, since it depends on those inputs to control the chopper. There are clever ways to align the INU while in-flight, but these generally have great amounts of error, due to the fact you're trying to "zero" the INU while you're moving with respect to the Earth (even in the best hover you can achieve, the chopper is still fidgeting, and those little movements reduce accuracy), which greatly increases the importance of a good pre-flight INU alignment.

There is no indication for INU alignment. Not sure if there is any in the real bird.

Yes, the groundspeed comes from the DNS (doppler navigation system)

Which, if true, is scary! While an INU alignment quality indicator by no means a required design element, it sure seems awfully strange to leave out such an easy and important indication.

My guess is, there is a set time in the manual and the pilot, using the helicopter stop watch, know when the time is right and the INU is aligned.

My guess is, there is a set time in the manual and the pilot, using the helicopter stop watch, know when the time is right and the INU is aligned.

"Out of place" isn't the same thing as "impossible", of course, or even "unreasonable". My curiousity on the subject is just getting more and more intense and I'd just love to hear confirmation one way or the other.

<speculation>Such a function would fit best with the PVI, possibly something not yet implemented? Maybe the "K-1","K-2" features? Or perhaps there's a quality indication when the "Normal" alignment button is pressed? Just guesses.</speculation>

Hmm, using a quick start procedure, I can takeoff from a cold start in about 100 seconds (1:40). The aircraft position on the PVI updates normally, velocities, times to waypoint, etc., are also all good, and the autopilot is able to maintain attitude and velocity in Route mode, long before the ground speed comes up in the HUD, all indicating a good INU solution. Based on this and the "Doppler Nav" warning that sometimes comes over the EKRAN, I suspect the HUD ground speed velocity is actually coming from a doppler velocimeter (see http://www.digitalcombatsimulator.com/index.php?end_pos=950&scr=default&lang=en, search for "doppler"). Doppler velcoimeters work by bouncing some sort of wave (sound, radar, laser) off of the ground (or other reference surface) and calculating the relative velocity from the doppler shift of the returned signal. I doubt they'd use an acoustic doppler system on a chopper, and either a radar or laser system will need warm-up time, so...

 

Anyways, trying to takeoff without a sufficiently aligned INU will result in your nav system being way off, in position, velocity, and attitudes. (see http://www.f-16.net/f-16_forum_viewtopic-t-634.html for one informative discussion on real-life INU alignment concerns). This, of course, would render the autopilot stupid, since it depends on those inputs to control the chopper. There are clever ways to align the INU while in-flight, but these generally have great amounts of error, due to the fact you're trying to "zero" the INU while you're moving with respect to the Earth (even in the best hover you can achieve, the chopper is still fidgeting, and those little movements reduce accuracy), which greatly increases the importance of a good pre-flight INU alignment.

I was wrong. :) Not sure then why I seem to remember the 3-minute rule for the INS. Maybe a memory pocket from FC?

With so many systems, it's amazing you can keep track of any at all as well as you do!

I am not sure but, I was online one day and I couldnt understand why the auto pilot wasnt working, the route mode and also if I recall the hover mode.

The only thing that I think I did wrong was take off as soon as the engines were good to go, everything was turned on as it was quickstart takeoff, but I dont think I waited for 3 minutes, if it applies that is ? but on that flight many moons ago, route mode wouldnt work, it wouldnt even light up and I think the auto hover button did not work also.

Those faults could of been something else entirely, but the only thing that I did differently on that flight was take off as soon as the engines were good to go and most if not all things being turned on whether on the ground or seconds after I took to the air.

That problem never ocurred again as I always waited for a few minutes before takin off afterwards and also, if it was a bug then it would of affected the previous install that I had when I first came across that problem, but it only happened that once and as stated, the only thing I did differently from normal flights was that I didnt wait for a few minutes before takin off, I was too eagre to get into the air.

I havent tried to see if that was the case for those functions not working, but it was/is the only thing I can think of.

There is a waiting time of 2 to 3 minutes after the K-041 is switched on where "HUD no ready" is indicated. K-041 is labeled "target and navigation system" on - off. So my guess is, INU on - off doesn't necessarily start calibration. Perhaps calibration is startet with K-041 and the indicator is "HUD no ready"? Just a question. Why else should "HUD no ready" last 2 to 3 minutes? It's just another indicator.

Here's a marginally educated guess: The INS and IRU systems I've used have been similar in appearance to the PVI and all have a status function with a countdown allignment counter. My W.A.G is that the alignment process can be monitored by one of the right-hand keys on the PVI that currently have no in-game function. I've never heard of an INS that can align in less than seven minutes--but aviation is a big world and there's lots I haven't heard of.

There are quick alignment procedures for military aircraft, and they usually include radar target or fly-over correction later. In the case of EINS, self-explanatory.

There are quick alignment procedures for military aircraft

A "cold start" requires a complete alignment process that takes more than 3 minutes. Quick align only works when the system is already operational and needs some refinement due to accumulated errors. Typically one uses quick align during a short turn-around. It cannot be used during flight because the platform needs to be absolutely stationary.

Is there planned some INU model improvements (for example, gyro drift and more PVI-800 modes) for DCS:Black Shark at some point in the future?

Regards!!