Speed Secrets: Using Video to Self Coach
By Ross Bentley
August 04, 2014
This week, driver coach Peter Krause, writes specifically about using video. Whether you're using a video system integrated with data, a "GoPro" (the "Kleenex" of video cameras, as it could be a GoPro, Contour, Sony, or...), or your smartphone with an app like Track Attack or Harry's Lap Timer, the use of video is an awesome self-coaching tool. - Ross
One of the greatest tools for driver improvement, one that has become ubiquitous, is on-board video and audio. You only have to scan cars in the paddock or on the grid to know that this setting could be the background for a GoPro advertisement! Going further, "intelligent video," or video laden with key driver performance data (playable immediately or shortly after returning to the paddock), has been one of the greatest leaps forward in the ability of drivers to coach themselves, as well as a boon to those professionals who assist drivers striving to identify opportunities for improvement.
The mind is a very powerful thing. We often remember things the way we could have liked them to be, rather than as they were.... We craft careful and ideal memories of all the precise turn-in points we used, the perfect apexes we hit, all of the expansive road that we used on track out, only to find that when we pop in the video card and hit "play," we are FAR off the mark! Not only that, we aren't executing that precision from corner to corner, let alone from lap to lap. Even drivers at the highest level bemoan opportunities lost during a qualifying lap, especially in the post-session interview! No one is immune. So what can you do to fix this?
Step One is to develop a strategy and workflow to regularly review your video. If possible, use or obtain a system that can overlay lap times, g-loads and a friction circle, at the very least. Optimally, a real-time overlay of throttle and brake (either actual pressure or negative longitudinal g's in a bar graph) onto the video itself, ready to play, is best. Make sure the system is reliable, fully-charged (or better yet, has switched power supplied) and has plenty of room on the memory card.
You can't self-critique if you don't have the video of your representative performance! How many times have I heard the lamentations of drivers, swearing and cursing their flaky, dead-battery, "memory full," "forgot to turn it on," cheap-ass cameras after setting their personal best, only to find nothing to review or even a record of what they did to DO that! What a shame. even the least expensive Mobius, GoPro or Replay camera can provide good video (and some offer good sound, shedding light on the level of throttle or brake commitment at various points on the track) which can aid in your analysis, but they're cheap for a reason and they ALL require care and feeding.
When I am engaged in private driver performance analysis, I nearly always place multiple and redundant systems in a client's car because for many drivers, if we don't get video, we don't have much to talk about. It's THAT important! Two systems that I recommend, sell a fair number of, and use myself are the AiM SmartyCam HD and the Video VBOX Lite or HD. Both systems write to the video (real-time) a variety of cogent, clear information that is incredibly valuable. Not only can the best lap be instantly identified and "zoomed in" on, but vMin (the lowest speed after each speed adjustment, either braking or "breathing" the throttle just before or in a slower corner), vMax (the highest speed achieved on any particular straight or terminal velocity on the longest straights) and g-loads, lateral (cornering) and longitudinal (braking and acceleration) are all there for comparison and validation, at a minimum.
For more advanced video analysis, the addition of engine RPM information, throttle position, and brake pressure can offer tremendous amounts of potential opportunity, as well as to reinforce the basic skill executions we all know are important for top- performing drivers. Something as simple as Sir Jackie Stewart's sage advice: "Do not go to throttle until such time as you can continue applying it," can be validated and checked with the information present on the screen, recorded in real time! Plus, we can review this information thirty seconds after we get out of the car - no assembly or matching of video and the collected data, no post processing or computer crunching required. The easier and more reliably your video works for you, the more you're going to use and get value out of it!
If you are using video only, make sure that you take some steps to improve the information you get out of it. Number one is to mount the camera at least at eye-level, ideally in the plane of the main roll hoop, aimed slightly down (10-15 degrees from level) and towards the centerline of the car at the front bumper point. This allows you to see the front corners of the car (hopefully) and their relationship to the edge of the road, several driver inputs like steering wheel speed and amplitude, shifting, and the top of the right knee to gauge throttle application (in a LHD car).
Number two is to optimize audio, preferably using an external microphone placed near the exhaust. This sheds further insight into the level and placement of throttle application, clean-ness of shifting, and speed of deceleration under braking (as long as drivers don't declutch when slowing down! No that's not recommended!). Quite often, just the audible cues presented by the engine note can offer great insight into the driver's comfort level, confidence, and commitment.
There are MANY driver performance executions that can be observed and compared using data-laden video. Here are three simple things you should look at that can make a material impact on lap times (assuming you have RPM and throttle position on the video). Even if you don't have access to this level of information, ALWAYS make sure you're using ALL the width of the road and hitting your apexes!
The first driver performance execution review is to look at the engine RPM in the slowest, but similar speed, corners (as identified by GPS speed or wheel speed on the video). Make SURE that you are in the most appropriate gear for the best output from the engine, and within the proper range. It's amazing how many drivers go through a particular corner at similar speed to another corner on the same track in a higher gear, because someone TOLD them to.
For instance, there are four corners at Virginia International Raceway that have a vMin within a relatively narrow range (within 4-8 mph, for most cars), but many drivers mistakenly use their lowest usable gear for only ONE of those corners, afraid of "over-slowing," instead of focusing on what is most important - digging out! If it makes sense for one, it will make sense for similar vMin corners.
Second, pay attention to the throttle application bar graph or percentage number. The most common execution error is to see throttle application begun too early, then cracked or reduced when it becomes clear that the corner is not done or that the car is washing out. Move the end of the braking zone up to or into the beginning of the cornering phase so that WHEN you go to power, you can follow Sir Jackie's advice! While you're watching the green bar, make sure also that the bar is FULLY down when the wheel is straight or near straight (and you're not needing to brake), and make sure that the throttle bar goes from fully lit (100%) to naught (0%) as quickly as possible at the end of the acceleration phase in transition to braking. How many drivers have told me, "I was SURE I was FULLY on the gas..." only to see the dip in the throttle position? Free time....
Third, using the g-loading readout (many systems use a "friction circle" with numerical values shown, in addition), make sure you see good, consistent numbers under braking. At least -1.0 g on a flat, level and straight braking zone, more on an uphill braking zone, and consistent throughout the entire braking zone until trailing off. If not consistent, consider that you might inadvertently be releasing brake pressure when rolling or stabbing the accelerator on heel-toe throttle blips. Then, make sure you are registering good, steady state cornering numbers (lateral g) from corner to corner. Obviously, favorable and unfavorable track topography will affect the limits, but it should be pretty close. If the numbers are good, put that corner to bed and look at the lower value corners to focus your concentration on.
By far the most valuable on-screen g-load readout is CombG or Gsum. This number is a measure of the total grip available and typically exceeds most steady-state longitudinal g (fore and aft) and lateral g (side to side) numbers. What is MOST important is NOT to see too much (if any) of a dip in the CombG number in the critical transition from end of braking to max cornering. Some corners will be better than others - work on the biggest drops first by gradually edging the ENTIRE braking zone closer to where you're picking up throttle and assuming lateral g buildup. THIS is the single greatest difference I see between fast and REALLY fast drivers, managing THAT transition most efficiently! Walk that ball around the OUTSIDE of the friction circle, if you lack a CombG or Gsum number on the screen.
It's amazing what modern, "intelligent," data-laden video can show, if only you bother to regularly look!
- Peter Krause