Wheel Brakes

Just for the record, apart from all 3 warbirds, MiG-15 and F-86 can "unstuck" themselves and taxi on the grass too nowadays (using high thrust, but still). The F-5 falls into the similar weight category I presume (haven't checked)? The grass near runways doesn't seem to be as "sticky" as it used to be in 1.2.x.

So instead of tire friction, anymore word on the idle thrust issue? If I have some time this week, I'll do some testing and record it. I'm really curious as to how to address what I *think* is an issue, but I'd also like to know if I'm completely out to lunch, here.

I recently managed a few decent landings (still no serious aero braking), but I find if I touch down around 130 kts, I can usually stop before the very end of the runway. I'm right on the verge of falling out of the sky before the fenceline, though, and on short runways, it's still not possible to stay on the tarmac without the chute.

Have you read this ? http://forums.eagle.ru/showthread.php?t=172406

and definitely related:http://forums.eagle.ru/showthread.php?t=172442

Hadn't seen the 2nd post, but the 1st was something I was hoping to draw some more attention to - I didn't see any responses or a notice of the issue being worked on. I was curious to see if this is a verified bug by Belsimtek, or maybe there's something weird going on with one or more clients. So I figured I'd do a test to try and repeat what you tested and get some video of it to add to the report.

My two cents on this issue. Approach and land with air-brakes out around at approximately 150 kts. I keep the airspeed indicator in the green all the way to touch down. After touch down cut throttle and keep the stick 3/4 to full back. Use 50-70% toe brakes, differentiating pressure to keep the bird centered on the runway until below 50 kts. No brake chute needed. I've been landing at Nalchik and Batumi this way with several 100 feet to spare... Not even close to running off the runway. To be sure... I have no idea if this is the standard operating procedure for the F-5E but as of right now it keeps me from running off the runway. Happy to post a track if anyone needs it.

Also, ensure you trim for landing = 5+.

A very simple temporary fix is: Don't reduce the throttles to idle when reducing thrust before the flare. Simply reduce them only to 60%.

60% is the RPM which creates the least amount of thrust.

Ballooning during the flare, excessive flare distance, all that doesn't happen in this case :)

 

@Azazel

Apart from the too high idle thrust problem users withoutout pedals/brakes can't use the wheelbrakes at all because when using a key you are applying 100% pressure and the wheels immediately lock.

This problem, combined with the F-5s tendency to accelerate after touchdown, makes it impossible to stop on the runway without using the chute.

BTW, the correct procedure would be to cut the throttle way before touchdown and the AoA indexer should be showing only red.

Agreed, having pedals is a must as keyboard users can't play along properly ever. I think I do end up cutting throttle before touchdown but most of my approaches are probably too shallow so I usually have some power still on.

You should be always in trim during the whole approach but you shouldn't trim anymore when starting the flare.

But of course :)

A very simple temporary fix is: Don't reduce the throttles to idle when reducing thrust before the flare. Simply reduce them only to 60%.

60% is the RPM which creates the least amount of thrust.

Ballooning during the flare, excessive flare distance, all that doesn't happen in this case :)

 

@Azazel

Apart from the too high idle thrust problem users withoutout pedals/brakes can't use the wheelbrakes at all because when using a key you are applying 100% pressure and the wheels immediately lock.

This problem, combined with the F-5s tendency to accelerate after touchdown, makes it impossible to stop on the runway without using the chute.

BTW, the correct procedure would be to cut the throttle way before touchdown and the AoA indexer should be showing only red.

How did you figure out that 60% is min thrust ?

Ok thats really interesting. I did some simple ground tests. From a standing start I needed 62% to get the aircraft moving. Once moving I selected 60% aircraft was slowly accelerating. at 15Kts I selected Idle (50%) aircraft decelerated and eventually came to a stop.

Ok thats really interesting. I did some simple ground tests. From a standing start I needed 62% to get the aircraft moving. Once moving I selected 60% aircraft was slowly accelerating. at 15Kts I selected Idle (50%) aircraft decelerated and eventually came to a stop.

Same here (well it would of course).

For pedals without toe brakes consider using the joystick rudder twist as a brake if you have it. I also do this for hand braking as in the MiG-15 and no doubt the SpitIX when it comes out.

For left twist braking set Axis Tune as:

Slider and User Curve

Deadzone 0

Saturation X & Y 100%

Curvature 100%

L-R Values 100 48 22 7 2 0 0 0 0 0 0

It's not perfect and the last stage of the twist drops the brake back to zero but you probably won't go to max brakes anyway.

Steer with rudder until nose-wheel steering below 60 knots.

btw, hand brake systems will have assisted rudder steering through distribution of hydraulic pressure but not of course on the F-5.

On the main topic, I have to agree that something needs to be done about the wheel brakes. I don't have an axis to bind them to, so they lock up at the slightest touch. It makes them almost completely unusable as even when lightly tapping the brakes while taxiing, they still lock up.

BST needs to do something about this. Either make the brakes come on much slower when you press the button, maybe a separte bind for half-brakes, or add some kind of gameplay assist thing where it feathers the brakes as you would with pedals. This is one of my biggest issues with the F-5 right now and in everyday handling of the plane makes it much more of a hassle than it should be.

I just recently picked up the F-5 and after setting up a profile in my Cougar HOTAS, I did some practice landings to get familiar with this A/C. Like others in this thread, I find this plane very difficult to handle during roll-out.

The best way to land successfully is to deploy the chute first. Then wait until the A/C has slowed down to a slow speed before employing the wheel brakes. Once you are very slow, then it is safe to enable nose steering. If you enable nose steering too early, it is so sensitive I usually end up in a skid.

Attempting to land the plane without the chute is near impossible for me as it is easy to get into a skid and end up sliding sideways or backwards.

I see this A/C (nothing in the full manual) does not appear to have an "Anti-Skid" brake system, so it seems like the wheels are locked up when ever the brakes are used?

Bill Clark

I just recently picked up the F-5 and after setting up a profile in my Cougar HOTAS, I did some practice landings to get familiar with this A/C. Like others in this thread, I find this plane very difficult to handle during roll-out.

 

The best way to land successfully is to deploy the chute first. Then wait until the A/C has slowed down to a slow speed before employing the wheel brakes. Once you are very slow, then it is safe to enable nose steering. If you enable nose steering too early, it is so sensitive I usually end up in a skid.

 

Attempting to land the plane without the chute is near impossible for me as it is easy to get into a skid and end up sliding sideways or backwards.

 

I see this A/C (nothing in the full manual) does not appear to have an "Anti-Skid" brake system, so it seems like the wheels are locked up when ever the brakes are used?

 

Bill Clark

I assume you mean you deploy the chute immediately after you have touched down, not 'before you land'?

As noted, the brakes seem to be both very weak and sensitive to skidding. I need some practice. You definitely need to bind a handy switch to the chute deployment. Up until last night I was using the handle in the cockpit, and it is not very practical when trying to keep the jet straight doing 150 knots.

This isn't a complaint about the flight model, as I'm sure it's modelled quite accurately. No one ever said landing an F-5 was easy. Although I did read once that the T-38 and F-5 were great for student pilots due to their tame handling. I guess it's a matter of perspective.

Here are some of my most recent attempts. Don't laugh too hard :D

Cheers,

I noticed that there is a lack of friction. Even if you drift sideways, you slide like on ice.

Not sure if it's a bug or i have no idea :D

I noticed that there is a lack of friction. Even if you drift sideways, you slide like on ice.

Not sure if it's a bug or i have no idea :D

Well, the tyres are narrow to fit into the wings. They have a small footprint, they aren't broad racing slicks.

The EE Lightning had a similar problem and despite a takeoff weight of 15-20 tons and brakes full on the tyres could not hold the runway on takeoff above 90% power, they would drag along the runway.

Brake friction Faulty

I think F5 is one of the more beautifull and complete modules of DCS.

But the Braking action and reaction is completely wrong !!.

Any aircraft that reacts like the F5 in DCS with this model of wheel or runway friction would ,and should, be banned from flight.

It is impossible that the present friction model is correct.

It is modeled as if the runway is constantly iced over.

No other module in DCS is having that low wheel friction.

Specially the way the aircraft slides sideways,is a give away that the friction models is completely unrealistic.

It is clearly a bug and should be fixed ASAP,...can not be that hard, i believe.

F5 is still in beta, i know, but it takes to long before there is at least a reply from the Devs on this.:mad:

Greetz

I think F5 is one of the more beautifull and complete modules of DCS.

But the Braking action and reaction is completely wrong !!.

 

Any aircraft that reacts like the F5 in DCS with this model of wheel or runway friction would ,and should, be banned from flight.

 

It is impossible that the present friction model is correct.

It is modeled as if the runway is constantly iced over.

No other module in DCS is having that low wheel friction.

 

Specially the way the aircraft slides sideways,is a give away that the friction models is completely unrealistic.

 

It is clearly a bug and should be fixed ASAP,...can not be that hard, i believe.

 

F5 is still in beta, i know, but it takes to long before there is at least a reply from the Devs on this.:mad:

 

Greetz

Wrong or not, it is not the final release and presumably the devs will take these things on board and consider them carefully. Patience.

I think F5 is one of the more beautifull and complete modules of DCS.

But the Braking action and reaction is completely wrong !!.

 

Any aircraft that reacts like the F5 in DCS with this model of wheel or runway friction would ,and should, be banned from flight.

 

It is impossible that the present friction model is correct.

It is modeled as if the runway is constantly iced over.

No other module in DCS is having that low wheel friction.

 

Specially the way the aircraft slides sideways,is a give away that the friction models is completely unrealistic.

 

It is clearly a bug and should be fixed ASAP,...can not be that hard, i believe.

 

F5 is still in beta, i know, but it takes to long before there is at least a reply from the Devs on this.:mad:

 

Greetz

There is nothing wrong with the friction model, and the F-5's ground handling is accurate. Due to the F-5's short wing and clean aerodynamic design, it as a high approach speed. The aircraft also has very narrow tires, and does not have an anti-skid system, meaning if you lock the brakes, it's just going to slide. That is why the F-5 was fitted with a chute to aid in its stopping distance. The T-38 is the same, except without the chute. Because of the T-38's incredibly long stopping distance, Talon Pilots in the Air Force need special permission to land at any airfield less than 8,000 feet in length.

You're just used to aircraft with slower landing speeds, more effective air-brakes, and wheel anti-skid systems. The F-5 has none of those, so you must plan your landings carefully and use subtle braking. Also, keeping the nose up on landing role (aerodynamic braking) helps shorten your landing distance.

The F-5 is not the only aircraft affected by this. The M-2000 is having a similar issue with friction. But as somebody said before, the two modules are still in beta phase, so let's be patient until we have a final release.

Of the betas I currently have, the F-5 is by far the best modeled and the one with least issues besides a handful of issues to be solved, one being the friction issue with the landing gear.

Many modules are still in beta not reach final for years.

So, they removed this module from "beta" status, but this problem still persists.

But since the idle thrust problem has been fixed, the solution to reduce the braking capability to less than 50% in the FM config file works really nice, if you use a key for braking in the F-5.

That way you keep the wheels from locking and you keep full controllability :)

How do I do that? The plane drifts around too easily and I lose control after after landing. Thanks

dcs>mods>aircraft>f-5E>FM>config.lua

Change the left & right wheel_brake_moment_max from 5500 to e.g. 2000.

Changed it to 2700 and it solved the problem. Thank you very much for your help, ground control is very smooth now.

Can't talk for you guys but on my side landing is a hell of a lot easier now after the update!