Route mode

[mrtube]

In route mode, does the helo auto climb to the required height , or do you have to input that yourself. I tried it out for the first time last night, but could not decide how it worked properly. Can you switch it on striaght away from a hover on take off and will it also pitch down to attain the right airspeeed as well? Or does it just provide steering input? And do you need to trim while in route mode?

 

Thx

[sobek]

You need to trim for your desired airspeed and the AP will try to maintain that speed. Route mode has no influence on the collective, only altitude hold mode has that.

[Frederf]

Aye, the ALT hold feature only holds the BR/RD altitude that is captured when you release the collective brake (default: F). It doesn't do assigned altitude or vertical rates.

 

If you engage ROUTE from a hover I don't think you'll actually go anywhere, or anywhere fast. It might crawl along very slowly.

 

The AP has 20% authority over the cyclic range so there are certainly times to trim during AP flight. Trimming also allows the heading hold feature to capture the desired heading (or heading rate for 3deg/sec+ turns after the patch) and for the speed hold feature to capture the current airspeed.

[mrtube]

thx for the reply Sobek, what do you mean by "trim for the desired airspeed" ? I understand from your reply that you must input the collective to achieve the required altitude, what about the rest? Does the system purely just turn the helo to the required waypoint and thats it? thx

[mrtube]

Woops, frederf seems to have replied while I was replying and answered my questions, thx guys

[sobek]

thx for the reply Sobek, what do you mean by "trim for the desired airspeed" ?

 

It means that when route mode is engaged and you trim, the airspeed at that moment is set as the desired airspeed and the route AP will try to maintain that.

[mrtube]

Ok thx, it does that by raising or lowering the nose to increase or decrease airspeed? You dont have to do that for it? And what if by raising the nose, you start to rise ( or descend if doing the opposite) Already stated above that the system does not affect the collective, so do you have to input the required collective change yourself after the system raises or lowers the nose to adjust airspeed?

[sobek]

Ok thx, it does that by raising or lowering the nose to increase or decrease airspeed?

 

Is there another way? ;)

 

And what if by raising the nose, you start to rise ( or descend if doing the opposite) Already stated above that the system does not affect the collective, so do you have to input the required collective change yourself after the system raises or lowers the nose to adjust airspeed?

The trick is to enable route mode when you're already in a stable forward flight with the collective set to maintain altitude, then it just flies by itself and does not raise or lower the nose a lot.

[mrtube]

Hi Sobel, I meant the system does it, as opposed to the pilot!! I am sure you understand what I meant!!

 

I am just curious how the system will adjust airspeed, if it has no action on the collective, and consequently, how much pilot input is required when in route mode.

 

And thanks for your patience with me !!

[sobek]

It has limited influence on the cyclic, pilot input is needed to trim the cyclic to a range from which the route mode will be able to maintain the speed with it's 20% authority and to control the collective (if not in altitude hold). everything else is done by the AP. Just try it out with this in mind and you will see how it works.

 

And thanks for your patience with me !!

no sweat, you're giving me an excuse to pause from learning :) Edited March 9, 2009 by sobek

[BTTW-DratsaB]

Good question, I was wondering how this worked. When I first went to use the route mode I expected it to automatically adjust collective and maybe speed, like it does with the steering. I think this is how the SU25 and A10 "route modes" work, so I guess that's where I got my assumptions. (Note to self - "helos are not airplanes"..repeat :) ) I had pretty much figured it out after playing around with it a few times, but this thread helps clear some things up for me, thanks.

 

One more question though, does the 20% authority rule apply to the collective also, when ALT HLD is on?

[sobek]

One more question though, does the 20% authority rule apply to the collective also, when ALT HLD is on?

 

It applies to all AP channles, IIRC.

[BTTW-DratsaB]

I have another question on this that I cant seem to figure out. If I use Route mode, how do I know what preset mission altitude and airspeed I should be flying at along the path for each of the various waypoints?

[EinsteinEP]

I have another question on this that I cant seem to figure out. If I use Route mode, how do I know what preset mission altitude and airspeed I should be flying at along the path for each of the various waypoints?

You should read the notes you made during your flight briefing ;).

 

Seriously, though, if the mission designer didn't state flight altitudes in the mission description, you can manually get it from the ABRIS (the PLAN submodes lists alts for each waypoint as programmed, see manual page 3-40 through 3-41). FYI, this info does not get automatically fed into the autopilot: you'll still have to achieve the desired altitude, set the collective brake, and engage the AP.

[BTTW-DratsaB]

Got it, thanks. I know this isn't the SU25T or the A10 :), but I think I remember when flying on those it would give you "Required Altitude" and "Current Altitude" on the top of the HUD in nav mode, the same for enroute speed. I'm surprised that this info is not included on the HUD in the KA. Never mind, the soultion you provide is good enough. If anyone knows why they dont do this on the KA50 or perhaps helos generally, it would be interesting.

 

cheers

[AlphaOneSix]

Got it, thanks. I know this isn't the SU25T or the A10 :), but I think I remember when flying on those it would give you "Required Altitude" and "Current Altitude" on the top of the HUD in nav mode, the same for enroute speed. I'm surprised that this info is not included on the HUD in the KA.

 

It is, you jut need to go into Flight Director mode on the autopilot. You'll get HUD cues for altitude, speed, and heading. Check the flight manual starting on page 6-18.

[slug88]

It is, you jut need to go into Flight Director mode on the autopilot. You'll get HUD cues for altitude, speed, and heading. Check the flight manual starting on page 6-18.

 

Doesn't the ADI give the same info without FD?

[AlphaOneSix]

Doesn't the ADI give the same info without FD?

 

It sure does! The question was specifically about the HUD, so I completely forgot about the ADI. It's very useful, but a bit harder to read.

[EinsteinEP]

It is, you jut need to go into Flight Director mode on the autopilot. You'll get HUD cues for altitude, speed, and heading. Check the flight manual starting on page 6-18.

The FD indicates the delta between the current altitude and the AP input altitude, but BTTW-DratsaB's post was asking about the mission-planned altidues.

How do I know what preset mission altitude and airspeed I should be flying at along the path for each of the various waypoints?

[BTTW-DratsaB]

The FD indicates the delta between the current altitude and the AP input altitude, but BTTW-DratsaB's post was asking about the mission-planned altidues.

Yes indeed, I had thought the FD might do it a while ago. But as you say it only shows you your desired airspeed and altitude, as set by the Trim. Not the required values for a mission route.

 

But I think the ADI might have it, from the manual it sounds like this does show you the required Speed and Alt as set out by the flight plan. Ill try it later. Still odd to me it's not on the HUD anywhere.

 

Also, I'm not 100% sure but wouldn't switching the FD on while your in Route mode negate the advantage of using Route Mode? As it just puts you back in manual flight, but with cues to follow.

Edited March 17, 2009 by BTTW-DratsaB

[BTTW-DratsaB]

Tested the ADI. It just does the same thing that the FD does, show you deviation from the last altitude and speed as set by the Trim and Collective brake. I guess you just have to go to the plan section in the Abris. :noexpression: Wonder how they did it before that was installed.

[Frederf]

The ABRIS is the only thing that could have mission values set in it. FD, ADI-director, HUD, etc do not have access to any mission flight parameters. Non-ABRIS systems are only capable of keeping trimmed or otherwise set-in-flight parameters such as altitude, airspeed, or heading.

 

The only real exception is PVI way/airfield/navtgt points and those are only good (flight-wise) for heading.

[hyperfighter]

It has limited influence on the cyclic, pilot input is needed to trim the cyclic to a range from which the route mode will be able to maintain the speed with it's 20% authority and to control the collective (if not in altitude hold). everything else is done by the AP. Just try it out with this in mind and you will see how it works.

 

no sweat, you're giving me an excuse to pause from learning :)

 

the 20% authority rule only aplies when u the pilot gives input, if the pilot doesnt touch cyclic or collective the ap basically has 100% authority. (or u can say 20% of 100 = 20 authority vs 80% of 0 = 0 authority)

one important point, if u want to use enroute mode make sure u have adf off.

same goes for autohover, dont forget to disable alt-hold after using auto hover.

[BTTW-DratsaB]

The ABRIS is the only thing that could have mission values set in it. FD, ADI-director, HUD, etc do not have access to any mission flight parameters. Non-ABRIS systems are only capable of keeping trimmed or otherwise set-in-flight parameters such as altitude, airspeed, or heading.

 

The only real exception is PVI way/airfield/navtgt points and those are only good (flight-wise) for heading.

 

How important is it on a mission to know what your required altitude and speed are? Maybe I think its more important than it actually is. I have only really flown one practise mission several times I made myself, for training.

 

From other sims, it always seemed like it was fairly high priority. So you arrive at the waypoints at the right time or fly at a speed that is not going to cause you to run out of fuel before the mission is over etc.

 

I guess when I start doing lots of different missions I'll get used to checking the Abris at every waypoint change to verify required speed and altitude. At the moment it probably seems more cumbersome than it actually is in practise.

 

Anyway, thanks for the info.

[hyperfighter]

hi BTTW-DratsaB, first of all i havent found that fuel is ever a problem, also taking lesser fuel is not really necessery (its free anyway) because u dont need to go mach 2 or pull more g's or anything like that.

that out of the way, when u want to fly clean first trim your helo to be stable at the speed and hight indicated, then simply use enroute mode ® and thats all, have a beer :P.

if u insist on manual flying i think its better to go to a waypoint a bit early, opposed to planes a chopper can just wait and hover a few mins and then arrrive spot on time