Test Pilot time: Short field landings.

[tspear]

Nope, there will be more brake heat. Max braking occurs just before the tires skid. The more weight on the tires, the harder they can brake before they skid.

If you can brake with exactly 1G of deceleration force you may match the additional weight assuming the brakes can take the additional heat.

However I have never managed to perfectly balance the additional force with additional brake pressure. Maybe you have more skill with this perfect balance.

I know even with antilock brakes in my car, weight affects stopping distance.

Tim

Sent from my SM-J737T using Tapatalk

 

[tawood]

If you can brake with exactly 1G of deceleration force you may match the additional weight assuming the brakes can take the additional heat.

However I have never managed to perfectly balance the additional force with additional brake pressure. Maybe you have more skill with this perfect balance.

I know even with antilock brakes in my car, weight affects stopping distance.

Tim

Sent from my SM-J737T using Tapatalk

But its wrong to assume HOW it will affect stopping distance...since a human factor is involved, a person could skid when light, and not when heavy, resulting in shorter distances when heavy.

 

[tspear]

But its wrong to assume HOW it will affect stopping distance...since a human factor is involved, a person could skid when light, and not when heavy, resulting in shorter distances when heavy.

Correct, but my point is that weight is a factor also. Based on comments from the OP, where there likely is not much fuel burn (the primary change in weight), it likely is a negligible error.

Tim

 

[Mooney Fan]

I think he means "instead of" rather than "in favor of".

Maybe.

It was a poor attempt at sarcasm. At my last BFR the CFI commented if I was on a PSEL check ride I would bust since I start my decent and approach abeam the numbers with the base turn soon to follow. He called that 'diving' at the runway, I responded no, it's the way I learned to fly. When the RWY is available, take it. He went on to comment on how the FAA wants to see a longer more stabilized approach, thus my comment, 'drag it in' on a 3-mile final.

 

[Salty]

It was a poor attempt at sarcasm. At my last BFR the CFI commented if I was on a PSEL check ride I would bust since I start my decent and approach abeam the numbers with the base turn soon to follow. He called that 'diving' at the runway, I responded no, it's the way I learned to fly. When the RWY is available, take it. He went on to comment on how the FAA wants to see a longer more stabilized approach, thus my comment, 'drag it in' on a 3-mile final.

I do stabilized “simulated engine out 180” landings all the time. Being stabilized is even more important for that type of landing.

 

[MauleSkinner]

It was a poor attempt at sarcasm. At my last BFR the CFI commented if I was on a PSEL check ride I would bust since I start my decent and approach abeam the numbers with the base turn soon to follow. He called that 'diving' at the runway, I responded no, it's the way I learned to fly. When the RWY is available, take it. He went on to comment on how the FAA wants to see a longer more stabilized approach, thus my comment, 'drag it in' on a 3-mile final.

Ask him where it says so in the ACS.

The applicant demonstrates the ability to:
Complete the appropriate checklist.
Make radio calls as appropriate.

Ensure the airplane is aligned with the correct/assigned runway or landing surface.
Scan runway or landing surface and the adjoining area for traffic and obstructions.

Consider the wind conditions, landing surface, obstructions, and select a suitable touchdown point.
Establish the recommended approach and landing configuration and airspeed, and adjust pitch attitude and power as required to maintain a stabilized approach.

Maintain manufacturer’s published approach airspeed or in its absence not more than 1.3 VSO, +10/-5 knots with gust factor applied.
Maintain crosswind correction and directional control throughout the approach and landing.
Make smooth, timely, and correct control application during round out and touchdown.

Touch down at a proper pitch attitude, within 400 feet beyond or on the specified point, with no side drift, and with the airplane’s longitudinal axis aligned with and over the runway center/landing path.
Execute a timely go-around if the approach cannot be made within the tolerances specified above or for any other condition that may result in an unsafe approach or landing.
Utilize runway incursion avoidance procedures.

 

[Mooney Fan]

I do stabilized “simulated engine out 180” landings all the time. Being stabilized is even more important for that type of landing.

I hear you. But I think the FAA would not agree based on their guidance. Assuming a 300'fpm decent rate with an approach speed of lets say 75mph, that puts us on a 1 1/4 mile final.


Factors of a Stabilized Approach
 Maintain a specified descent rate.
 Maintain a specified airspeed.
 Complete all briefings and checklists.
 Configure aircraft for landing (gear, flaps, etc).
 Be stabilized by 1,000 feet for IMC operations; 500 feet for VMC approach.
 Ensure only small changes in heading/pitch are necessary to maintain the correct flight path.

 

[MauleSkinner]

I hear you. But I think the FAA would not agree based on their guidance. Assuming a 300'fpm decent rate with an approach speed of lets say 75mph, that puts us on a 1 1/4 mile final.


Factors of a Stabilized Approach
 Maintain a specified descent rate.
 Maintain a specified airspeed.
 Complete all briefings and checklists.
 Configure aircraft for landing (gear, flaps, etc).
 Be stabilized by 1,000 feet for IMC operations; 500 feet for VMC approach.
 Ensure only small changes in heading/pitch are necessary to maintain the correct flight path.

Why assume 300 fpm? (Minute or mile...either can be substantially more and still be stabilized).

 

[Clip4]

We had a healthy discussion on the Mooney Pilots group on Facebook regarding landing technique that morphed a bit into short field landings, and there were plenty of unresolved assertions. Well, my engineer brain didn't like that, and my pilot brain decided that doing some testing sounded like fun.

I’m planning to do some research/flight testing to determine the theoretical and actual effectiveness of some different techniques, and I figured that crowdsourcing the design of the tests would help to make them as effective as possible. I will take another pilot with me to help collect and record the data safely. I’ll update the remainder of this post as we refine the plan:

First of all, to eliminate as many variables as possible, I’ll do all my approaches to the same runway, using the GTN 750 visual approach feature with autopilot and a consistent power setting so that the approaches are all the same. That means at least a 3-mile final, I’ll probably plan a base leg around 4 miles out and drop the gear at 3 miles as the glide slope is intercepted.

I’ll also rotate through the following scenarios rather than doing all reps of a single scenario and moving on to the next scenario. By rotating through them, the effect of the inevitable changes in wind, temperature, and aircraft weight should be minimized.

I’ll have a GoPro mounted underneath the plane to help with measuring where touchdown and the end of the roll occur.

I'm planning on doing the entire following list of scenarios 3 times. Here are the scenarios I’m thinking of doing:

1) Flap retraction time, engine off.
2) Flap retraction time, engine running, airplane stationary on the ground.
3) Flap retraction time, in slow flight.
(The above don’t need to be in the rotation, as they don’t involve a landing - I'll do them first)

4) Landing distance and flap retraction time during landing roll, no wheel braking. Will take airspeed at touchdown, beginning and end of retraction as well as the amount of time it takes for retraction.
(All of the above will give us the time it takes to retract flaps and determine the variation, if any, caused by differing bus voltages and aerodynamic loads.)

5) Landing distance, Flaps down throughout landing roll, no wheel braking.
6) Landing distance, Flaps down throughout Landing, speed brakes extended upon touchdown, no wheel braking.
7) Landing distance, Flaps down throughout landing, speed brakes extended at end of flare, no wheel braking
8.) Landing distance, Flaps down throughout landing, speed brakes extended at beginning of flare, no wheel braking.
9) Landing distance, flaps down throughout landing, speed brakes extended at end of flare, nose held off until control effectiveness is lost, then full aft elevator for remainder of landing roll, no wheel braking.

(“Max braking effort” as used below means as much pressure as possible without skidding, thus the pressure will necessarily vary throughout each individual landing roll and between tests.)

4a) Landing distance, Flaps retracted upon touchdown, max effort braking after retraction complete, elevator neutral
4b) Landing distance, flaps retracted upon touchdown, max effort braking right away, elevator neutral
5a) Landing distance, flaps down throughout landing roll, max effort braking
6a) Landing distance, flaps down throughout landing roll, speed brakes extended upon touchdown, max effort braking
7a) Landing distance, flaps down throughout landing roll, speed brakes extended at end of flare, max effort braking
8a) Landing distance, Flaps down throughout landing, speed brakes extended at beginning of flare, max effort braking.
10) Landing distance, Flaps down throughout landing, speed brakes extended at end of flare, elevator full aft, max effort braking.

I’ll do the tests in the following order to minimize the effects of brake temperature: 4a, 4,4b, 5, 5a, 6, 6a, 7, 7a, 8, 8a, 9, 10. I’ll also take a break after each series to help with my alertness and performance, replace the batteries in the GoPro, and give the brakes a chance to cool further.

Other data to record: Temp, Dewpoint, and winds for each test.

Any thoughts or suggestions are appreciated. I've got a thread on the Mooney Pilots group, but I'm posting the link here mainly because it's freaking impossible to find anything on Facebook after a couple of days have passed.

The whole thing sounds silly to me. 1st, there is no landing where I would turn off the engine. 2nd, if the plane is equipped with speed brakes the shortest landings will be achieved with the brakes activated, but you are going to have a high sink rate that you had better be on your game in the flair. 3rd, you don’t have much flap on a Mooney and flap retraction after landing will have minimal effect.

 

[benyflyguy]

If you are sticking with a standard localizer glideslope approach, then you're only assessing the contribution that breaking technique has on stopping distance. That's a very small subset of factors that affect short field landing performance. A steeper approach at lower than standard landing speeds will result in a shorter overall ground roll for a given level of braking. Brian Painter is one of the few pilots I know of that has used a Mooney for backcountry flying and he perfected techniques for getting his M20 down and stopped quickly. Ultimately he decided the Mooney wasn't the best plane for the job with his growing family, but here's a video of him in action when he was flying the M20:

I didn’t see the “runway” until the end of the roll out. That was crazy!!!!

 

[Clip4]

It was a poor attempt at sarcasm. At my last BFR the CFI commented if I was on a PSEL check ride I would bust since I start my decent and approach abeam the numbers with the base turn soon to follow. He called that 'diving' at the runway, I responded no, it's the way I learned to fly. When the RWY is available, take it. He went on to comment on how the FAA wants to see a longer more stabilized approach, thus my comment, 'drag it in' on a 3-mile final.

Heck if going to take a runway when available just land mid field from the down wind.

 

[Silvaire]

Seems unnecessarily way over-thought, land at slowest speed practical and stomp on the brakes. I doubt flaps or speedbrakes or elevator are going to have much of any effect at that point, at least not enough to justify all the effort put into monkeying with them.

 

[SoCal RV Flyer]

Nope, there will be more brake heat. Max braking occurs just before the tires skid. The more weight on the tires, the harder they can brake before they skid.

Until you heat them so much that they start to fade, and/or cook the O-rings in the cylinder bore, resulting in nasty, smoking fluid loss. Then the distances get reeeaaaallly long!

 

[Eric Stoltz]

I like this idea for a test. I know in my airplane, Beech Sierra, that the huge placard that says, "raise flaps to increase brake effectiveness" is a very worthy endeavor. I have seen the effect with my own two eyeballs. I even have video of the compression of the struts compressing at the same time of raising the flaps, increasing the weight on the wheels... And therefore increasing the effectiveness of the brakes. I'm curious to see if it works the same for the legendary Mooney.

I look forward to the results.

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[dtuuri]

Until you heat them so much that they start to fade, and/or cook the O-rings in the cylinder bore, resulting in nasty, smoking fluid loss. Then the distances get reeeaaaallly long!

Absolutely! However, I did mention "brake energy" in an earlier post:

Not needed. For a given speed and within brake energy limits, the stopping distance will be the same.

If you can brake with exactly 1G of deceleration force you may match the additional weight assuming the brakes can take the additional heat.

I think this is worth repeating. 1G of deceleration is the most any airplane can muster, mathematically, before the tires skid. So, yes you are right, I was talking in theoretical terms. It is a principle worthy of some thought, though, imo.

 

[tspear]

Seems unnecessarily way over-thought, land at slowest speed practical and stomp on the brakes. I doubt flaps or speedbrakes or elevator are going to have much of any effect at that point, at least not enough to justify all the effort put into monkeying with them.

In the Aerostar I had previously, speed brakes and flaps both made significant difference in landing roll out distance.
In the Cirrus I fly now, removing flaps also makes a huge difference in landing distance.

Here is another reason to do it. Crosswinds, when you land you lose the ability to slip or crab. Slip or crab are what create the horizontal component which prevents you from moving sideways. The longer you have minimal weight on wheels, the more likely a gust is able to push you off the runway. Dumping the flaps actually gives you significantly more directional control faster. Something very critical in gusty/crosswind conditions.

Oh, and those who state this is bad form because you may raise the gear instead of the flaps? Only if you fly Beech. Beech seems to be the only model which has this issue, and a host of other ergonomic issues where pilots do dumb things.

Tim

 

[Salty]

In the Aerostar I had previously, speed brakes and flaps both made significant difference in landing roll out distance.
In the Cirrus I fly now, removing flaps also makes a huge difference in landing distance.

Here is another reason to do it. Crosswinds, when you land you lose the ability to slip or crab. Slip or crab are what create the horizontal component which prevents you from moving sideways. The longer you have minimal weight on wheels, the more likely a gust is able to push you off the runway. Dumping the flaps actually gives you significantly more directional control faster. Something very critical in gusty/crosswind conditions.

Oh, and those who state this is bad form because you may raise the gear instead of the flaps? Only if you fly Beech. Beech seems to be the only model which has this issue, and a host of other ergonomic issues where pilots do dumb things.

Tim

The mooney flaps aren’t very big or effective.

 

[Bill Watson]

The mooney flaps aren’t very big or effective.

Not a Mooney expert by any means, but I recall the Mooney’s flaps being very effective in ground effect. I assumed it was related to how close the wing is to the ground.

So I’m thinking the flaps effect on braking effectiveness could be significant. Data on that would be interesting.


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[Hank S]

The mooney flaps aren’t very big or effective.

They're plenty long, about 2/3 of each wing. But compared to Cessna 40º flaps, not very effective. Similar to 30º Cessna flaps, I thought. But what do I know, I rarely use mine for takeoff [except when loaded heavy for travel], and rarely use more than Takeoff flaps [15º] to land, but I do tweak them a little if I'm high. Landing flaps [33º] are reserved for dead calm days, or when I've blown it badly and am high, but I usually recover and remove some flaps by short final.

 

[eman1200]

The mooney flaps aren’t very big or effective.

this is so true that most mooney drivers have the flaps removed.

 

[Salty]

this is so true that most mooney drivers have the flaps removed.

And installed as extra equipment on a bonanza?

 

[Hank S]

And installed as extra equipment on a bonanza?

Is that why they glide like rocks when you pull the power on final???

 

[flyingcheesehead]

The whole thing sounds silly to me. 1st, there is no landing where I would turn off the engine.

Who said anything about turning off the engine?!?!?

2nd, if the plane is equipped with speed brakes the shortest landings will be achieved with the brakes activated, but you are going to have a high sink rate that you had better be on your game in the flair.

You're talking about decreasing distance over an obstacle, and you're right... But I haven't found an FAA-standard 50-foot obstacle anywhere around here and the techniques that were being discussed in the original thread on Facebook had nothing to do with obstacles, only ground roll. I don't think there's as much debate over how to get down after an obstacle. Speed brakes, flaps, slips all work fine.

With the speed brakes, it's not just the sink rate that causes trouble, as that is still quite manageable. The real problem is that you're blanking out 10-20% of your wing's lift, and when you're slow and need increased AoA to arrest the descent, that lift is important to have. While it can be done, after significant experimentation, I do not use the speed brakes during the round-out. Even if I have them out for the entire approach, I'll pop them in and then pop them back out a few seconds later. What I'm talking about for this experiment is extending them at the end of the round-out to help get the wheels on the ground as quickly as possible.

3rd, you don’t have much flap on a Mooney and flap retraction after landing will have minimal effect.

The mooney flaps aren’t very big or effective.

They're plenty long, about 2/3 of each wing. But compared to Cessna 40º flaps, not very effective. Similar to 30º Cessna flaps, I thought. But what do I know, I rarely use mine for takeoff [except when loaded heavy for travel], and rarely use more than Takeoff flaps [15º] to land, but I do tweak them a little if I'm high. Landing flaps [33º] are reserved for dead calm days, or when I've blown it badly and am high, but I usually recover and remove some flaps by short final.

I use takeoff flaps on every takeoff and full flaps on every landing and they're quite effective. You're right that they aren't like 40º 182 flaps, but while they have a shorter chord, they have a much wider span than the 182 flaps. Dunno what @Clip4 and @Salty are talking about...

 

[Bill Watson]

You're talking about decreasing distance over an obstacle, and you're right... But I haven't found an FAA-standard 50-foot obstacle anywhere around here and the techniques that were being discussed in the original thread on Facebook had nothing to do with obstacles, only ground roll. I don't think there's as much debate over how to get down after an obstacle. Speed brakes, flaps, slips all work fine.

With the speed brakes, it's not just the sink rate that causes trouble, as that is still quite manageable. The real problem is that you're blanking out 10-20% of your wing's lift, and when you're slow and need increased AoA to arrest the descent, that lift is important to have. While it can be done, after significant experimentation, I do not use the speed brakes during the round-out. Even if I have them out for the entire approach, I'll pop them in and then pop them back out a few seconds later. What I'm talking about for this experiment is extending them at the end of the round-out to help get the wheels on the ground as quickly as possible.

If it’s only about ground roll, then all issues concerning roundout and descent rate are moot since you are measuring things only after touchdown.

So you touch down at absolutely the slowest speed possible, speed brakes fully deployed, followed by maximum braking. Seems like the only variables left for experimentation is the dumping of the flaps and elevator position. Should be very doable and will produce interesting data.

Getting over an obstacle and stopped in minimum distance is the real world situation I’ve always found most interesting. It has a built in spot landing requirement and is where pilot skill at executing optimal techniques is required. Crepe paper strung between poles would be the way to do the obstacle.



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[Silvaire]

...Oh, and those who state this is bad form because you may raise the gear instead of the flaps? Only if you fly Beech. Beech seems to be the only model which has this issue, and a host of other ergonomic issues where pilots do dumb things.

The instrument panel of the original Bonanza was absurdly symmetrical. Everything was controlled by fourteen identical piano key switches, seven of which were blanks, along the bottom of the panel.

https://goo.gl/images/ogcESS

 

[flyingcheesehead]

If it’s only about ground roll, then all issues concerning roundout and descent rate are moot since you are measuring things only after touchdown.

So you touch down at absolutely the slowest speed possible, speed brakes fully deployed, followed by maximum braking. Seems like the only variables left for experimentation is the dumping of the flaps and elevator position. Should be very doable and will produce interesting data.

Well, I guess "ground roll" isn't the right thing to say then. "Runway used" maybe. There was discussion about whether the speed brakes would do any good, so that's still part of the test.

 

[Clip4]

Who said anything about turning off the engine?!?!?



You're talking about decreasing distance over an obstacle, and you're right... But I haven't found an FAA-standard 50-foot obstacle anywhere around here and the techniques that were being discussed in the original thread on Facebook had nothing to do with obstacles, only ground roll. I don't think there's as much debate over how to get down after an obstacle. Speed brakes, flaps, slips all work fine.

With the speed brakes, it's not just the sink rate that causes trouble, as that is still quite manageable. The real problem is that you're blanking out 10-20% of your wing's lift, and when you're slow and need increased AoA to arrest the descent, that lift is important to have. While it can be done, after significant experimentation, I do not use the speed brakes during the round-out. Even if I have them out for the entire approach, I'll pop them in and then pop them back out a few seconds later. What I'm talking about for this experiment is extending them at the end of the round-out to help get the wheels on the ground as quickly as possible.





I use takeoff flaps on every takeoff and full flaps on every landing and they're quite effective. You're right that they aren't like 40º 182 flaps, but while they have a shorter chord, they have a much wider span than the 182 flaps. Dunno what @Clip4 and @Salty are talking about...

In a 252 I have used the speed brakes from the last 50 ft to end of ground roll, but you are going to use a lot of elevator.

 

[Eric Stoltz]

In a 252 I have used the speed brakes from the last 50 ft to end of ground roll, but you are going to use a lot of elevator.

I don't have speed brakes on my Sierra, and never have flown a little plane with them. Why would you deploy them at 50'? Just curious, not trolling with bait.

 

[Clip4]

I don't have speed brakes on my Sierra, and never have flown a little plane with them. Why would you deploy them at 50'? Just curious, not trolling with bait.

You are defeating ground effect.

 

[idahoflier]

I have zero Mooney experience, so take that into consideration, but that said, if the flaps are as effective as you say, I would think retracting flaps after touchdown would afford maximum braking and therefore the shortest landing distance. As someone else alluded to, I would be concerned about flat spotting one or both tires. Possibly postpone until Spring when grass is available? Last thought, I have a Stratus which logs my position and speed around 10 Hz I think (tracklog feature), perhaps you have a device with similar capability? If so it should be easy to "normalize" your results so you're comparing apples to apples... Have fun!

 

[flyingcheesehead]

Last thought, I have a Stratus which logs my position and speed around 10 Hz I think (tracklog feature), perhaps you have a device with similar capability? If so it should be easy to "normalize" your results so you're comparing apples to apples... Have fun!

Oooh, that's a good idea. The Stratus logs at 10Hz??? I thought most of those things logged at 1Hz. Are you just getting the track log out of ForeFlight then, or doing something else? I do have a Stratus but I don't really use it any more since we got the GTX345.

 

[idahoflier]

Oooh, that's a good idea. The Stratus logs at 10Hz??? I thought most of those things logged at 1Hz. Are you just getting the track log out of ForeFlight then, or doing something else? I do have a Stratus but I don't really use it any more since we got the GTX345.

Yeah, looks like I was mistaken. If the data is uploaded from my iOS device it looks like it's 1 Hz, but if it's uploaded from my Stratus it's ~3 Hz. I am pulling the .csv out of Foreflight and then doing the epoch conversion on the timestamp. I have a Stratus ESGi so my position is from the ESG GPS receiver so that's probably why it updates faster. I haven't cared enough to figure out why sometimes the tracklog source says "Ipad" instead of "Stratus", just figured it was a bug in Foreflight or the Status firmware (or operator error)...

 

[Kenny Phillips]

Heck if going to take a runway when available just land mid field from the down wind.

Something my CFI had me practice.

 

[Kenny Phillips]

Absolutely! However, I did mention "brake energy" in an earlier post:

​

I think this is worth repeating. 1G of deceleration is the most any airplane can muster, mathematically, before the tires skid.

Really? Why are planes limited to 1G, but not automobiles?

 

[Clip4]

Really? Why are planes limited to 1G, but not automobiles?

The larger tire of an automobile has more surface contact per tire, 2x as many tires are used for braking, and an automobile does not have its weight on the tires reduced by a small amount of lift being produced by the wing.

 

[Kenny Phillips]

The larger tire of an automobile has more surface contact per tire, 2x as many tires are used for braking, and an automobile does not have its weight on the tires reduced by a small amount of lift being produced by the wing.

While that may make it more difficult to attain one G decel, it certainly doesn't limit it.

 

[dtuuri]

Really? Why are planes limited to 1G, but not automobiles?

My guess would be the road surface friction (OK, so I Googled). Imagine (my words now) having sprockets instead of tires to land on and that you land on long straight bicycle chains fixed to the runway. As long as the sprocket teeth don't break you should be able to stop a whole lot shorter than on dry concrete with a tire.

I'm not an engineer and my knowledge of this one-G maximum braking phenomenon came from an ex-National Guard pilot I used to fly with who was familiar with aircraft brake testing experiments done at Edwards AFB long ago. He said to imagine a pendulum of one "G". As you brake, it swings forward, but can't go higher than horizontal, at which point there would be no more "G" force on the runway. I accepted the principle, but always suspected the explanation. Maybe one of the resident engineers here can enlighten me/us?

 

[FastEddieB]

Really? Why are planes limited to 1G, but not automobiles?

You read my mind.

 

[Kenny Phillips]

You read my mind.

Yeah, I know for a fact that using two rear wheels ONLY for braking can exceed one G on some vehicles. It's possible, but not likely, in an airplane. The 1G limit may be practical, but it's not the limit. Of course, nobody wants larger stickier [and shorter lasting] tires and big brakes, and the associated weight and air drag.

 

[Bill Watson]

I wish I had spent more time and effort in physics and math classes. With that said, the braking force, which comes from frictional forces opposing forward motion, is a function of the force applied normal or perpendicular to the runway.

In the case of an aircraft, that force maxes out at the weight of the aircraft which I’m thinking is equivalent to 1G.

In the case of automobiles, particularly race cars, the force can be more than 1G. It can be the weight of the car plus aerodynamic down force.

With aircraft, we struggle to get all the weight borne on the braking wheels; 2 point rollout, spoilers, retracted flaps, minimal angle of attack.

With automobiles all the weight is already on all 4 braking wheels, there is no lifting force, and in the case of race cars, there can be significant downforce. Downforce increases friction between the tires and road surface which can be used to keep the car on the road and for increased braking force.

Am I getting close to something?


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