Author Topic: Flight Model Comparisons  (Read 16433 times)

SUBS17

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Re: Flight Model Comparisons
« Reply #15 on: December 31, 2011, 06:12:23 pm »
Regarding the trim, one feature I noticed in the super hornet sim, is when you adjust trim with your thumb on the stick, the trim value appeared on the HUD briefly. This was a helpful feature when in the pattern and getting the proper trim value set.

Mike, can you ask your son if the trim value shows up on the Charlie Hornet's HUD?

To the HUD developers on this forum, I think adding this feature to the HUD would be helpful in the pattern, instead of having to look for the trim setting on the checklist page, and since we don't have "seat of the pants" feel or stick force feedback in FSX or sim flying.

The trim value appeared on the HUD only when you changed it, displayed for about 2 seconds above the tacan distance in the lower right.

-CAPT

I'm now going to have to check that on the VRS SH hud. ;D

MikeB54

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Re: Flight Model Comparisons
« Reply #16 on: December 31, 2011, 07:58:40 pm »
Hey Mike,

As Sludge mentioned, I have been working on a somewhat elaborate Pitch Auto Trim system. It first trims to 1.0 G and then to 0 pitch rate.  It only does this once the the simulator has sensed that the pilot is not providing any pitch input (i.e. flight stick has been released).  Once pitch input has been sensed from the pilot, the trim zeros out and allows the pilot to control the Hornet as normal, and then goes back to re-trimming the aircraft once controls are released again.  I designed the autotrim system to only work when the landing gear is retracted, allowing the pilot to have full control of the trim for takeoff and landing operations.

Like the SLUDGE, my variant is a work in progress.

If you have the time, it would be great if you can check it out and give me some honest feedback (and anyone else for that matter).  

Here's the link if you are interested.
http://www.fsxblueangels.com/forum/viewtopic.php?f=91&t=4584



I downloaded and flew it this morning.  My first impression was that I liked it. The autotrim worked well.  Point the nose where you want it and it stays there. Speaking of the autotrim, to be more realistic it should activate when the flaps are set to auto rather than gear up.  

Started with a field departure from Miramar using the Pitot Heat switch to set the takeoff trim.  Hands off the nosewheel lifted off at about 140 kts.  That might be a tad early but it depends on A/C weight so since there were no stores it is probably about right.  Chris didn't seem concerend about it.

I flew out to a carrier, did the break at 800' and 350 kts.  BTW, the break turn uses what Chris called the 1% rule.  I think we have talked about that before.  The G you pull in the turn is 1% of your airspeed, i.e. at 350 kts you should be pulling a 3.5G turn.  Once the hook, gear and flaps were down I dialed in a little nose up trim.  Long story short, first pass was an OK 3 in vLSO.

There is still the need for some aft stick in a turn.  According to Chris, it really isn't needed on the real jet when in a carrier pattern.  At least not as much as you need in FSX.  When the jet is trimmed it holds "on speed" and you use power to compensate for the loss of lift in the turn.

On a catapult launch I used the pitot heat switch with the launch bar down to set the takeoff trim.  On launch, the waterline goes up to about 8 degrees and stays there until changed by control input.  It should be closer to 10.  Also, since the cat is overpowered in FSX, I usually use 85% N2 on the cat.  To see if that made a difference i also did a launch using MIL power.  No change in the waterline symbol behavior.

To sum it up, the only thing that Chris didn't like was the amount of forward and aft stick needed to fly it.  That's probably a limitation of FSX that we just have to live with.

Mike
« Last Edit: December 31, 2011, 08:04:42 pm by MikeB54 »

MikeB54

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Re: Flight Model Comparisons
« Reply #17 on: December 31, 2011, 08:00:38 pm »
Regarding the trim, one feature I noticed in the super hornet sim, is when you adjust trim with your thumb on the stick, the trim value appeared on the HUD briefly. This was a helpful feature when in the pattern and getting the proper trim value set.

Mike, can you ask your son if the trim value shows up on the Charlie Hornet's HUD?

To the HUD developers on this forum, I think adding this feature to the HUD would be helpful in the pattern, instead of having to look for the trim setting on the checklist page, and since we don't have "seat of the pants" feel or stick force feedback in FSX or sim flying.

The trim value appeared on the HUD only when you changed it, displayed for about 2 seconds above the tacan distance in the lower right.

-CAPT

According to Chris, that feature was just added in a recent software release but it isn't trim that it is displaying.  It is the AoA the the jet is trimmed for.

Mike

jimi08

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Re: Flight Model Comparisons
« Reply #18 on: December 31, 2011, 11:05:57 pm »
I downloaded and flew it this morning.  My first impression was that I liked it. The autotrim worked well.  Point the nose where you want it and it stays there. Speaking of the autotrim, to be more realistic it should activate when the flaps are set to auto rather than gear up.  

Started with a field departure from Miramar using the Pitot Heat switch to set the takeoff trim.  Hands off the nosewheel lifted off at about 140 kts.  That might be a tad early but it depends on A/C weight so since there were no stores it is probably about right.  Chris didn't seem concerend about it.

I flew out to a carrier, did the break at 800' and 350 kts.  BTW, the break turn uses what Chris called the 1% rule.  I think we have talked about that before.  The G you pull in the turn is 1% of your airspeed, i.e. at 350 kts you should be pulling a 3.5G turn.  Once the hook, gear and flaps were down I dialed in a little nose up trim.  Long story short, first pass was an OK 3 in vLSO.

There is still the need for some aft stick in a turn.  According to Chris, it really isn't needed on the real jet when in a carrier pattern.  At least not as much as you need in FSX.  When the jet is trimmed it holds "on speed" and you use power to compensate for the loss of lift in the turn.

On a catapult launch I used the pitot heat switch with the launch bar down to set the takeoff trim.  On launch, the waterline goes up to about 8 degrees and stays there until changed by control input.  It should be closer to 10.  Also, since the cat is overpowered in FSX, I usually use 85% N2 on the cat.  To see if that made a difference i also did a launch using MIL power.  No change in the waterline symbol behavior.

To sum it up, the only thing that Chris didn't like was the amount of forward and aft stick needed to fly it.  That's probably a limitation of FSX that we just have to live with.

Mike

Big thanks to you Mike (and your son) for the feedback.  Some of the things you mentioned are easily fixable and others not so much.  The amount of forward/aft stick required is something that can be easily adjusted.  Same things with the waterline to 10 degrees.  As for getting the jet to trim based on AOA is doable.  I'm guessing that's why your son made the comments earlier about being surprised about seeing the Velocity Vector moving, but not the nose with power adjustments while on approach.  I'll give it another go when I have some time.  The Flaps operating in Auto only when the switch setting is in Auto is the only thing, I don't know how to do yet.  That involves detaching the flap switch position from the actual flaps position.  Right now, as soon as the actual flaps move, the switch moves which means that if i set the flaps switch to auto (up) as soon as the actual flaps go to move based on flight conditions, the the switch will move also and will no longer be in auto mode, and thus it will break the coding logic.  So I'm still working on that one. 

Thanks again Mike/Chris!  Very good feedback/information here!

Justin "Jimi" Hendrix
FSX Blue Angels
FSXBA F/A-18C Hornet Latest Download Link: http://www.fsdreamteam.com/forum/index.php/topic,6944.msg117011.html#msg1

GOONIE

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Re: Flight Model Comparisons
« Reply #19 on: January 05, 2012, 03:04:26 pm »

According to Chris, that feature was just added in a recent software release but it isn't trim that it is displaying.  It is the AoA the the jet is trimmed for.

Mike


Great, sounds like we need a software update for the FSX Hornet's HUD  ;)

Jivko, does this sound like something that can be added/displayed on the HUD you created?

-CAPT
"You've got to land here, son. This is where the food is."

Sludge

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Re: Flight Model Comparisons
« Reply #20 on: January 08, 2012, 09:29:30 pm »
CAPT...

For now, til JR does/doesn't decide to do a HUD fix, I put the "Trim" readout with the shift-6 (IFOLS/FuelTrapGauge) so you can instantly see what your trim is. That's another FSX workaround as we really cant "trim to feel" in FSX, obviously. When I get the newest Sludge out there, shift-6 will also be "special" so you can look at other views but it wont go away. It will always be enabled on lowering the tailhook, so you have that info avail for trapping. In the Sludge Hornet's current landing configuration, it trims about 3.3 NU, so I've set the auto-up trim (dirty, gear/hook down) logic to follow and sure enough, it holds really well.

Also, keep in mind, JIMI is working on AoA-based trim stuff on his Hornet, since we both took Chris' criticism to heart and are trying to implement fixes in our Hornets. BTW, you would NOT BELIEVE how much that threw both our "release schedules" off line. Don't get me wrong, it'll make the Hornet much better in the long run, but that real-world feedback just gave both our projects a good kick in the "you know where". I'm back to 3am nights trying to fix center of gravity, updated contact points, approach dynamics... all the while, improving gauge functionality.

Later
Sludge

MikeB54

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Re: Flight Model Comparisons
« Reply #21 on: January 08, 2012, 10:01:41 pm »
CAPT...

Also, keep in mind, JIMI is working on AoA-based trim stuff on his Hornet, since we both took Chris' criticism to heart and are trying to implement fixes in our Hornets. BTW, you would NOT BELIEVE how much that threw both our "release schedules" off line. Don't get me wrong, it'll make the Hornet much better in the long run, but that real-world feedback just gave both our projects a good kick in the "you know where". I'm back to 3am nights trying to fix center of gravity, updated contact points, approach dynamics... all the while, improving gauge functionality.

Later
Sludge

If it makes you feel any better, Chris was really impressed that you guys were doing so much to improve the realism of the Hornet.  :)

Mike

jimi08

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Re: Flight Model Comparisons
« Reply #22 on: January 08, 2012, 11:55:12 pm »
Thanks Mike.

Sludge,
After talking to a real-life Rhino driver classmate of mine, he informed me that the Supers do not autotrim to 8.1 in Manual, Powered Approach Mode and that it's all manual.  After going back and reading the NATOPS a few more times, the FCS system pretty much grabs and maintains a certain AOA based on trim setting.  Kinda like "dial-A-AOA". So it will maintain a certain AOA for a certain trim setting then adjust and maintain another AOA provided that the pilot has increased or decreased the amount trim. The Rhino guy did mention that some of the guys will do the BLIN code thing so as to trick the FCS so that it will automatically maintain an 8.1 AOA by default.

But doing the "dial-A-AOA" thing is a little above my head at this point.  To make a gauge to make this happen, would involve an algorithm that takes the current trim state and translates it into a AOA counterpart.  From there, it would use elevator trim to maintain the appropriate AOA.

For now, I have gone back to allowing the autotrim system to disengage once the gear have been lowered and allowing the pilot to have full control of the pitch trim so that he can set it to his/her liking.  As Chris said earlier, his approaches are very little forward/back input, while others (like you Sludge) tend to prefer to have a little aft-stick while rolling into the groove.  I figure this way, everyone can get what he/she wants.

I've been working on this thing for over 6 months straight now, I'm going to go ahead and release our variant sometime later today and push updates as I get them.

Sludge, Mike, Neutrino and Svicar, thanks again for your help with this project!
« Last Edit: January 08, 2012, 11:59:32 pm by jimi08 »

Justin "Jimi" Hendrix
FSX Blue Angels
FSXBA F/A-18C Hornet Latest Download Link: http://www.fsdreamteam.com/forum/index.php/topic,6944.msg117011.html#msg1

MikeB54

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Re: Flight Model Comparisons
« Reply #23 on: January 09, 2012, 01:11:51 am »


 The Rhino guy did mention that some of the guys will do the BLIN code thing so as to trick the FCS so that it will automatically maintain an 8.1 AOA by default.


Chris showed me the BLIN code trick when I flew the simulator at Miramar.  If I'm not mistaken, the value he had me set was 3025 but don't hold me to that.  I'm having a hard time finding exactly where he had me set that.  It's bound to be in the NATOPS somewhere.  When I find it I'll let everyone know.  If I can't find it in the NATOPS I'll fall back to Plan B and ask Chris.  LOL

Mike

Sludge

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Re: Flight Model Comparisons
« Reply #24 on: January 09, 2012, 03:10:54 am »
JIMI...

Yeah, my auto-trim stuff is just a workaround, since we haven't figured out how to write the XML stuff to get a selectable trim, nor can we actually "trim to feel". My auto-trim setup simply uses what works with the Sludge and allows for some who want the landing config trim dialed in "hands off". Then I can just have a pre-written XML for the more experienced FSX pilots who want full trim controls. The baseline release will have the auto trim (3.3 NU) engage once dirty/gear/hook down so that the casual flyer doesnt have to jack around with lots of UP trim (for those with lesser-than x52's, who dont have the buttons for trim on the stick) and just be a tad nose up stick required in the landing config.

Good, I'll have to download and fly it once I get a chance. Always welcome for any help I can give, friend!! Great job on your mods, so far!

Mike...

No worries, it was good to hear that because, to the extent possible (my own programming/modding skill, and FSX limitations), we want to put out the best product we can. Oh, if you get around to talking to Chris, can you ask him if the "v/vector and waterline rise on adding power" behavior is caused simply by the addition of thrust pushing the nose up or a function of the FCS AoA-trim? Or both? This will help me even more, in working the powered approach dynamics.

Later
Sludge

jimi08

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Re: Flight Model Comparisons
« Reply #25 on: January 09, 2012, 09:03:17 am »
FINALLY DONE (for now hehe)

I know this is "Sludge Country", but I have the FSXBA Variant uploaded to the website for those who are interested. You can download it from the following link:

http://fsxblueangels.com/hornet%20dowload%20template.html

Sludge,

I recently obtained the coding scripts for the majority of the buttons in the Acceleration Hornet's cockpit.  That was how I has able to link the Pitch Autotrim Disconnect on our variant to the Master Arm Switch in the virtual cockpit.

....so....I was thinking....between you, I and Neutrino, what if we were able to link all of the commands/functions of the Realistic/Combat HUD to their native counterpart buttons and switches in the virtual cockpit? Then we could either do way with the HUD control panel or have them both work in conjunction with each other???
...just a thought...

Justin "Jimi" Hendrix
FSX Blue Angels
FSXBA F/A-18C Hornet Latest Download Link: http://www.fsdreamteam.com/forum/index.php/topic,6944.msg117011.html#msg1

Sludge

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Re: Flight Model Comparisons
« Reply #26 on: January 09, 2012, 05:56:15 pm »
JIMI...

Quote
I know this is "Sludge Country"

Damn, now I'm getting whole countries named after me...?! No really, this is "who upgrades and tries to improve the FSX Hornet country". I'm just glad someone else is taking the mantle as well, my shoulders were getting tired.

Just downloaded, so when I get home from work, I'll let her rip and try to give you some feedback tonight.

Later
Sludge