Brakes on landing

[piksle]

I'm practicing landings, and they are going well, except for the crashing part when I can't stop before running off the end of the runway. I am using Beta 3 and trying to touchdown at around 150 ias, full flaps, anti-lock is on, Batumi. Throttle is all the way back, airbrakes full and I'm stomping (holding) the W key but nothing seems to happen. Eventually, I panic when hitting the grass and pulling on the emergency brake as I careen through the fence and trees. The brake works when taking off, because I hold them on and throttle up to 85%, and the nose is squashed down until I release them. I even tried popping the canopy up and tossing out loose clothing to no avail. Anybody else?

 

!!!Update!!! I found that I was landing too fast and just ran out of runway. I just have to keep practicing stalling right and letting it fall right on the blackmarks. If I'm to fast, the anti-lock system makes it feel like there are no brakes at all..

 

!!!Update2!!! And it gets more interesting. Upon flaring->touchdown, I would yank the throttle back. During the rush, I wasn't noticing the Left Hydraulic warning light. When I land with the throttle reasonably back to idle or just above, the pressure stays up.... whala.... plenty of brakes. I have an X52 stick and wasn't paying attention to how far back I needed to go.

Edited November 24, 2010 by piksle

[diveplane]

good videos on utube on landings.

 

[piksle]

That's the one I've been using. I best go back and review it again.

[diveplane]

make sure anti skid switch is on when landing

[Cooch]

OP, I have had the same experience of the no braking, this video, while very good does not mention it. Can anyone confirm, "W" is the key for braking (non pedal configuration) correct?

[Exangelus]

If anti-skid is off there should be a warn light burning. Furthermore, where do you touchdown? A simple fist rule is you need 2/3 of the runway at least to stop the aircraft before the end without the use of emergency brakes.

 

Ofcourse their are alot of factors involved in the calculation of your rollout length, for instance: temperature+altitude of field->pressure, runway condition(dry/wet/snow), weight of aircraft, touchdown speed, wind...

 

I'm guessing your landing with rather normal conditions (normal winds, dry runway etc..) so most important point is than the touchdown speed. I couldn't find the notes on the A10 in touchdown speeds but let me give a example from a glider aircraft, two completely different planes but they both need to land and stop in the exact same way, with a Discus B; if you touch down with 90km/h instead of 70 km/h you will have 44% more kinetic energy, meaning you'll need to lose much more energy to come to a stop which can result in you needing up to 1,5 times more length of runway.

 

As I said this is for a glider not a A10 but the principle is the same so the key to a good touchdown is accurate flaring, you'll approach with around 150kts but when flaring you must keep the aircraft from touching down as long as possible until it will fall (effectively stall ) on the runway. A common mistake is that the flaring takes up the half of the runway and thereby makes stopping in time impossible.

 

Hope this helps some, if you upload a track we can help analyze your landings! ;)

[gturn234]

W is the default key for brakes. Go into your options and check to see that W is your key for brakes. I had trouble with my pedal brakes till I realized that I had not assigned them in the options. Also, make sure your W key is the brakes both for the A-10 Game and A-10 Sim up in the left corner. That can be confusing as well if you are looking at the options for the sim and playing in game mode.

 

Hope this helps.

 

150 kias seems very high for landing speed as well. Check your weight with a little math before starting the mission. Remember that the rule of thumb is 120 KIAS for 30,000 lb aircraft and 2 knots for every 1000 lbs above that.

You should still be able to stop though, even at 150 kias.

 

Also, what Exangelus says is completely true. Batumi is I believe at 13 ft ASL so the altitude is no factor. Don't EVER try to land with a tailwind. Careful there. No wet runways until you work out this brake problem as well would be my advice.

Edited December 21, 2010 by gturn234

[Frederf]

I found that applying 10% or 100% left/right axial toe brakes results in the same brake effect on the aircraft. However the hydraulic pressure effect is hugely different. When I push both pedals to the floor the pressure absolutely dumps out of the left hyd system. When it gets very low I get braking problems.

 

If I brake with moderate pressure the hyd system doesn't suffer as much and I don't have those same problems.

[coder1024]

I saw the same thing - tried landing and held down W but it seemed to have no effect.

 

I wonder if you have to first engage NWS before the brakes work?

[Frederf]

Certainly not. Check the RCtrl-Enter display window to see the brakes meter "filling" more and more as W is held. Also keep an eye on the L HYD PRESS gauge.

 

If braking seems ineffective, release and reapply. Someone mentioned that this remedied ineffective braking.

[Echonomix]

150kts is a little quick. Shoot for around 130. Don't go under 120 else you could stall it out. Make sure you touchdown on the right part of the runway.

 

You can't wait and touchdown 1/2 way. You need to get the plane in a stable approach and vary the speed and descent with the throttle. Put the flight path marker (or total velocity vector?) at the end (closest to you) part of the runway and keep it there until 15-30 feet above, then flare the FPM to the far end of the runway while cutting the throttle. Then just wait for the plane to stall out about 1 foot or less above the runway and you have a landing :) Practice getting that (usually the dual white large rectangles, but you can land before those if you think you need too) right spot on the runway so you have enough room to stop the plane .

[coder1024]

I recall having all sorts of trouble trying to learn landing on Falcon 4.0 Allied Force. Keeping track of when you're supposed to have what airspeed and what altitude, etc, etc. I just found it complicated and rather difficult.

 

I ran across a tutorial which said to just keep track of 2 things.

 

1) keep the flight path marker on the end of the runway where you want to touch down - use the flight stick to maintain this

 

2) use the throttle to control angle of attack

 

So you're just doing those 2 things, holding the FPM with the flight stick where you want it to be, and then controlling the AoA with the throttle. This made landing amazingly simple for me anyway.

 

I tried the DCS A-10 landing and it seems like a similar approach might apply. I'm pretty new to it though so I'm sure someone will correct me if thats wrong, but it seems like it should work.

[Frederf]

In the Viper I would always land and whatever speed matched the AoA and then keep the nose up to 10-13 degrees or so until about at 90 knots and then lower the nose. Only when all three tires were on the deck would I brake. Keeping the nose up helped bleed a lot of airspeed due to the aircraft's shape.

 

I learned from civil to raise flaps after touch down to dump lift and put more weight on the tires for better braking effectiveness. Even elevator up was useful once you no longer had enough authority to lift the nose to apply more downward pressure This were tricks to squeeze every inch out of the landing roll.

 

Certainly the practice of using 40% speed brake on landing will help shed speed as well as keep the RPMs up for a quick go around if need be.

 

The F-16, being fly-by-wire, made pitch for path and throttle for AoA work really well because the FCC wouldn't move the FPM without stick input if it was capable. The concept of tuning your approach as you describe is still plenty valid in the A-10, just with more crossover effects.

[Echonomix]

Also in the f16 I think they usually burst a little bit of throttle on their flare, since the f16 doesn't get much lift from ground effect, afaik.

[coder1024]

well, at least in DCS A-10, you don't get a court-martial for destroying the fence as in Falcon or else I'd be in a load of trouble :)

[hassata]

Side note: emergency brake is not comparable to a car's emergency brake, or a brake to use in a braking emergency per se. I believe it is only engaged when the left engine fails, and you need the right engine to take over in connection with brake operation.

[Frederf]

Yup, emergency brake system uses RT HYD including a hydraulic accumulator on the right system in the case of both hydraulic failure. No anti-skid available.

 

I'm going to run a few landings with anti-skid off to see what pressures lock and which are simply close to locking.

[coder1024]

I did activate the emergency brake when I touched down, but I'm not sure it did anything so yea I guess thats not the way to do it :)

[Frederf]

The emergency brake just switches over to the other hydraulic system. You still need to press the toe brakes to activate them.

[Exangelus]

When I pull the emergency break handle I don't have to do anything and I come to a stop alot quicker than when I manually break (I don't constantly press the brakes full so that's the reason I brake slower)

 

My point, once you pull that handle, no need to push the brakes manually anymore.

[piksle]

I found I was throttling back to much on flare->touchdown and was receiving a Left Hydraulic Warning. Need to keep that throttle at idle or just above to keep from loosing pressure and thus brakes.

[Frederf]

That... shouldn't be true.

[Teej]

That sounds odd. I wonder if you're missing a switch flip.

 

I'm just mucking about playing with stuff...I've barely looked at the manual (just to see how far off base I was with my functional, but guessed rampstart). This is the result of a landing. There's no voiceover, just me thumping it down on the numbers and hauling it to a stop. Pretty boring, i know...that's why I haven't shared it. I was just messing around and wanted to show something to a friend of mine. Probably be pulling this back off youtube soon.

 

I just bought it last week after building my new system, and I've only flown it a few times (too busy) so no critiquing my technique. ;)

 

[JeffC]

I also cant get brakes. Under setup the wheelbrake line on/off is blank but the next line is "W" for brakes. no way to select the other line.

[Teej]

Interesting. I just went flying again.

 

After braking for a bit... L-HYD PRES starts blinking on the caution panel and braking force is much reduced....