Brakes overheating to easily?

[B777ER 2,509]

On 9/28/2018 at 11:22 AM, Bluestar said:

Kyle,

I was having a brake overheat issue with the B747-8 using FSUIPC and had to go in and adjust the SLOPE.  

Glad I saw this, my slope was on 0. Put it at - 10, much better, not as sensitive and twitchy. 

[B777ER 2,509]

2 hours ago, B777ER said:

Glad I saw this, my slope was on 0. Put it at - 10, much better, not as sensitive and twitchy. 

Meant to say +10.

[Rhinozherous 93]

On 11/4/2018 at 5:13 PM, B777ER said:

Meant to say +10.

Also want to setup FSUIPC correctly... So, the + numbers on the slope setting make the braking less sensitive? Tried to set it up but I was unsure if the slope should go to minus or plus 😋

[VHOJT 185]

3 hours ago, Rhinozherous said:

Also want to setup FSUIPC correctly... So, the + numbers on the slope setting make the braking less sensitive? Tried to set it up but I was unsure if the slope should go to minus or plus 😋

Yes, + will make it less sensitive initially, then the harder you press, the more sensitive it gets if you look at the curve.  Either way, you get 100% brake at 100% pedal, it's just about the curve that is applied.

Edited November 6, 2018 by VHOJT

[r_stopnicki 92]

Hello to all:

I just want to chime in here with my experience.

After installing the B748 update, I started to "blow" tires while taxiing both the B744 and the B748. It was a very frustrating experience, obviously, as I wasn't aware of the quick "maintenance" fix.

After learning about that fix, I kept blowing tires, but was fixing them several times during taxi in a large airport. Realism = 0

Got some very good pointers in this forum, and specifically this thread, and they are:

1) Do not taxi at ground speeds over 20 kts. It "feels" slow, because you are so high up.

2) Do not take 90deg curves at more than 10 kts. If you know that such a curve is coming up, start to slow down well in advance!

3) Tap the brakes. Tap ... let go .... tap ... let go

4) When landing, select AUTO BRAKES 3 as a matter of course and don't touch the brakes until well below 40-50 kts. Let the auto brake do what it is paid to do.

5) Last, but certainly not least, open up the GEAR page of the lower EICAS just before you start taxiing on departure and just before you land on arrival. And monitor it every time you have to brake, to see how the temperatures are increasing.

Nothing of what I said is new. It is all coming from this thread.

By doing the above things quite strictly, I did not have to touch the FSUIPC, the controls settings or the calibration of my pedals. And I have not blown a tire ever since.

Hopefully this helps somebody else!

Cheers

Roberto

 

[BK2 6]

On 10/29/2018 at 7:32 PM, KLM57 said:

I really don´t know how to overcome the problem with overheated breaks and exploding tires as long as PMDG keeps telling us, that we are doing something wrong and not admitting, that for simming purposes the 747-8 is bit too real in this respect...

 

I have the same issue obviously (otherwise I wouldn't be here...). It's less to none during Taxi but landings nearly 100% have this Brake heating/Tyre deflating issue. I completely agree with KLM57 saying "that for simming purposes the 747-8 is bit too real in this respect...". Hope PMDG does re-evaluate this matter.

 

Thanks

Benny K

[berts 97]

On 11/7/2018 at 9:35 PM, r_stopnicki said:

1) Do not taxi at ground speeds over 20 kts. It "feels" slow, because you are so high up.

2) Do not take 90deg curves at more than 10 kts. If you know that such a curve is coming up, start to slow down well in advance!

Some good advice here, although at light aircraft weights and on wet or contaminated surfaces even 5kts in a turn can occasionally result in some loss of directional control due to the nosewheel tyres losing their grip. 

The first things to check are your simulator's brake axis sensitivities and null zone settings, because they are often the cause of brake overheat issues. if you haven't configured them properly or at all, then there is the possibility your simulator program may be applying full parking brake pressure every time the rudder pedal toe brakes are depressed. 

In many ways, the wheels and tyres are one of the achilles heals of aircraft like the B744 and A380 due to their sheer mass and the brake energies involved in stopping them in an emergency.  For example, after a rejected takeoff in a B744 at Max TOW with the speed close to only 120kts KIAS the brake energies involved will almost certainly result in the fuse plugs melting and tyres deflating.  The B744's Brake Energy Cooling chart also requires no less than 1 million foot pounds to be added per brake unit for every mile spent taxying; which only adds to your deflating experience! 

When it is activated, the autobrake system will apply full brake pressure during any RTO above 85kts G/S; whereas for landing it uses a preselected deceleration rate depending on the autobrake setting in use.  It is also worth noting that on a dry runway with the aircraft in the landing mode the application of maximum autobrake deceleration will be LESS than that provided by manual braking, so it is relatively easy to get a brake overheat if you apply manual braking too early after touchdown.   Provided you apply full Reverse Thrust and Ground Spoilers immediately after landing the autobrake setting should not normally result in any significant brake overheat; in fact the system might not apply any brake pressure at all if the Reverse Thrust selection and drag from the Spoilers is sufficent to satisfy the lower autobrake deceleration rate settings.  Here's a few more tips:-  

• Never ride the brakes or use them to slow the aircraft down with engine thrust applied.
• Anticipate approaching all turns and holding positions by reducing the thrust to idle in good time.
• After landing consider shutting down the No3 engine, otherwise the aircraft will want to accelerate at the lighter weights.
• Always handle the brakes, wheels and tyres with care, especially when taxying out for a heavy weight takeoff.  They should then look after you when you might need them the most! 

Edited December 16, 2018 by berts

[downscc 1,327]

6 hours ago, BK2 said:

I completely agree with KLM57 saying "that for simming purposes the 747-8 is bit too real in this respect...". Hope PMDG does re-evaluate this matter.

What Bertie said.  Also, in considering if the simulation should be modified simply for "simming purposes" I would argue strongly that would be defeating the purposed of spending all that time and resource developing a high fidelity simulation.  I am confident that I speak for most pilots when I say that the ground movement segment of every flight is as important as the flight and in many ways is much more challenging and with higher risks.  Every student pilot is taught that they are piloting the ship on the ground, as opposed to driving.  We don't drive to the runway and then start piloting....and as Bertie said the size and mass of the B747 makes ground movement even more interesting than non-pilots may appreciate.

[BK2 6]

17 hours ago, downscc said:

What Bertie said.  Also, in considering if the simulation should be modified simply for "simming purposes" I would argue strongly that would be defeating the purposed of spending all that time and resource developing a high fidelity simulation.  I am confident that I speak for most pilots when I say that the ground movement segment of every flight is as important as the flight and in many ways is much more challenging and with higher risks.  Every student pilot is taught that they are piloting the ship on the ground, as opposed to driving.  We don't drive to the runway and then start piloting....and as Bertie said the size and mass of the B747 makes ground movement even more interesting than non-pilots may appreciate.

So, what do say Dan? That this simulation is not fit for "non-pilots" because they cannot appreciate the difficulty? Maybe we do not. Just teach us ("non-pilots") the same way PMDG has been teaching us for the last 10 years, starting with the NGX, how these magnificent machines are flying...

Just reminding that this is a desktop simulation and as far as I know it is not yet directed at real life training (albeit, I guess, maybe with PMDG products it might be taken this direction). Also there are ways this can be resolved with an option (like other items found in the PMDG setup menu) which one can choose from - Current "real life" braking model VS less sensitive braking model (which will not trip over brake temperature and explode tires every other landing).

 

That's for now.

Thanks

Benny K

 

[downscc 1,327]

2 hours ago, BK2 said:

Maybe we do not. Just teach us ("non-pilots") the same way PMDG has been teaching us for the last 10 years, starting with the NGX, how these magnificent machines are flying...

I think you have a point but I argue that you'll appreciate the complexity of ground maneuvering a jumbo jet all the more if you can change your attitude and decide this is something you want to learn.  Accept the challenge.  In reality, taxiing the B748 is not difficult if you follow a few simple concepts already laid out in detail in this thread.

[berts 97]

Benny, you have raised a very interesting point, because I know that even FSX has its uses as a training tool helping new flying instructors practise their instructional technique on basic exercises such as flying straight and level. 

Flight Sim aircaft in general are becoming far more sophisticated these days as the developers - and not just PMDG - have strived to simulate how all the controls, knobs, switches, bells and whistles work in the real machines.  With the advent of the latest 64bit simulators and advanced scenery files there has been another leap forward in this regard, because some addon aircraft like the PMDG 744 and -8 have ceased being mere toys for us to 'play' with and are rapidly becoming realistic tools for would-be pilots to train on.

Maybe there is a need to step back a little and look at how the flight simming world and these clever addons can be best tailored to suit the needs of a particular group of users?  Perhaps this is where the different simulator platyforms have a role to play (e.g. FSX/FSX-SE for the hobbyist, X-Plane for the would be stuident pilot and Prepar3d with its different licences for the PPL's and professional pilots)?  Speaking personally, I think aircraft like PMDG's DC6 which is available for XPlane probably got this right by having the best of both worlds with its on-board Flight Engineer, who you could use - or not - to read out and action the checklists and control the various systems of the aircraft for you.  It's just a shame he doesn't eat the crew chicken!         

Edited December 17, 2018 by berts

[sloppysmusic 324]

I spent years with the NGX which can be 'driven' to the start /finish line (sorry I mean RUNWAY) in a similar way to a warm up lap weaving the plane around to warm up the tires. Switching over to the 777 and this plane led to half my taxi races ending in required pit stops for new tires even before the race had begun! 

After some research and threads such as this one I decided the new challenge was to get from pits to start without using brakes at all, using airport maps to look ahead and plan my turn speeds better. This added a whole new fun challenge to my sessions and needless to say I have not had a single overheat or tire burst wreck my day since. 

For those who want the plane to be less sim like during taxi and more 'fun' and forgiving you already have the option of ahem, cough cough, applying reverse thrust which does a rather good job of slowing the behemoth down without destroying your brakes. Just don't quote me on that! 

:) 

[BK2 6]

49 minutes ago, downscc said:

I think you have a point but I argue that you'll appreciate the complexity of ground maneuvering a jumbo jet all the more if you can change your attitude and decide this is something you want to learn.  Accept the challenge.  In reality, taxiing the B748 is not difficult if you follow a few simple concepts already laid out in detail in this thread.

I certainly do accept the challenge. I am not about to waive away such a beauty. Taxing is not an issue for me any more (I read your instructions...). Landing while keeping A/C health in good shape at the end of this (and the runway) is the challenge. We need a "cook book" for this part of flying the 748.

Benny

 

[downscc 1,327]

22 minutes ago, BK2 said:

Landing while keeping A/C health in good shape at the end of this (and the runway) is the challenge. We need a "cook book" for this part of flying the 748.

LOL probably true.  I've found the best braking policy is to use autobrake to decelerate to 40 kts GS or below, then once you start using manual braking as required be sure to watch how quickly the GS value decreases.  We're missing the reality in our computer seats by not feeling the braking so the eye needs to be on the numbers.  A steady count down of one or two knots per second isn't going to over heat your brakes.

[paulyg123 135]

I have the ground crew on speed dial.  I always toast the brakes after every landing. I have the Saitek foot pedals.  Yes, autobarkes do the trick, but nothing like stomping on them yourself.  I noticed if I only apply the brakes 1/2 way, I get the asme braking power and don't cause over heating.    Try applying them 1/2 way.