The best pullers maximize hang time and distance with an innate understanding of physics.
April 3, 2018 by Benji Heywood in Opinion with 0 comments
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Let’s assume your goal is to throw the longest, floatiest pull you can, such that you’re able to chase it down and put pressure on the offense as soon as they catch it. There are lots of other ways to pull in different circumstances,1 but, assuming you’re throwing a normal pull, you want to get the best combination of distance and hang time. There’s little difference between a straight brick and a very long but low pull that gets there quickly and allows your opponent to make two centering passes before your defense arrives.
So what sort of throw should you be making? What sort of flight path do you want the disc to take?
I’m going to bet that there are aspects of the physics of flight that you haven’t considered, but which make a big difference in pulling. Take a look at Reid Koss’ pull below.
The Physics Of Hang Time And Distance
We’ll look at the simple physics of pulling first. It’s obvious that throwing the disc very high will, in general, increase the hang time but cost you distance. Fighting gravity to get the disc up there is going to reduce the amount of energy left over for traveling forward.
The trade off seems pretty severe: the high pull appears to cost you so much distance that it feels wrong to try and float it. What’s more, even if the perfect floaty pull isn’t too short, the trade off between height and distance is so severe that if you miss just a fraction high you can end up with the disc coming back to you, and so people err the other way. More often than not, you see lower, faster pulls that give the offense a free pass or two.
But the physics says that the trade off needn’t be as severe as it seems. We’re never going to be able to get a really high, floaty pull to go as far as a slightly lower one, but I’m going to argue that an outside-in pull may suffer a lesser loss of distance than an inside-out one—and that anyone practicing pulling should be experimenting with throwing OI.
What To Consider When Pulling
First, some inevitable definitions. When I talk about an OI pull, I mean a pull that curves from left to right for a right-handed, backhand puller2. I don’t necessarily mean it would be released at an OI angle—it probably wouldn’t be, as it would likely just blade from there—but rather that it turns over to OI after release and spends a good part of its flight turning to the right. Similarly, what I would call an IO pull is one that mostly curves from right to left.
We’ll also need to make use of the knowledge that the tilt of a disc changes during flight—specifically that the disc turns over early in the throw, and then as it starts to slow and fall it will fade back towards an IO angle and die off to the left.
Let’s look at what happens when we throw a high pull. Many of us will raise the front edge (we’ll call that “putting stall” on the disc) so that it will fly up into the air. It’s not easy to throw a flat throw upwards. We throw it upwards, but we also angle it upwards so that it slices cleanly through the air on its way up. If we do that, then we’ll get height, but of course the disc will still have a lot of stall on it as it slows, and sitting at that angle it’s very likely to want to drift back towards us. This is why beginner pullers really struggle to put height on the disc. They end up losing huge amounts of distance.
More experienced pullers will realize (even if not consciously) that it’s possible to get height without a lot of stall on the disc. Imagine you keep the front edge of the disc completely level with the back, but now tilt it strongly IO. If you throw this upwards and to the right, the disc will curve a little, so even though it started out to the right it will end up heading straight down the pitch again. And that considerable forward speed will flatten the disc out in the direction of travel, so the sideways-stall we took advantage of early in the throw will disappear, and you’ll end up with a high, straight disc with very little stall. You can get your pull nice and high but still without any stall.
You’ll lose a little distance compared to a less-high pull, as some energy does go sideways (and you can never beat gravity), but you will end up with a high, flat disc rather than a stalling one, and so the situation is much better than before. Even if you aim a fraction too high, it’s relatively unlikely that it will float all the way back to you. The trade-off of height and distance is less severe.
Make Your Pulls Work For You
What few people realize—unless they’ve played a bunch of disc golf or practice Maximum Time Aloft3—is that we can do even better.
All we need to think about is that the disc does not care which direction it was thrown in. It only feels the air hitting it now, so when we talk about it dying left, for example, that only means to the left of its current direction.
Imagine a flat disc traveling straight across the pitch, from the right sideline to the left sideline4. As it slows, it will tilt left, which actually means tilting back towards you, standing on your endzone line. Similarly, a disc traveling across from left to right would tilt away from where you’re watching it as it slows.
Now let’s think about our IO versus OI pulls. Our IO pull will curve to the left and, as it slows and dies to the left of its current path, it increasingly stalls (from the thrower’s perspective). Discs that curve right to left get steeper and steeper stall as they slow down, which is partly why it’s so easy to mess it up and have it fly back to you. If you ever do practice MTA and throw it IO, you’ll notice it comes back to you increasingly vertical, at a finger-breaking speed.
But the OI throw—specifically the S-curve pull which is released IO, gets up to a decent height, and then turns outside-in for most of its flight and stays high enough to stall and die at the end—will see decreasing stall (from your perspective). As it curves right, and slows down, it will die to its left, which is not your left but rather away from you. If it started with a little stall, it will flatten, and it may even start to fall forwards. Try throwing MTA with a little OI angle—not so much that it blades, but just so it is curving OI at peak height – and if you get it right you’ll see it float down gently. The stall you started with has declined.5
Analysis Of A Strong Pull
Look again at that above video of Reid Koss pulling the disc. You can’t see the disc for much of its flight, but what you do see is very interesting. As it comes down, you’ll notice the receiver has gone about eight yards further downfield than he should and has to run backwards to make the catch. It’s a high, towering pull which, from Reid’s perspective, dies forwards. The disc comes into the frame fairly flat and then die left towards the endzone. Even though he clearly releases it a little IO, I’m convinced that it turns early and spends much of its time out of shot actually curving to the right (OI) before straightening as it dies at the end.
An alternative is that there’s a breeze from right to left. Indeed, the highest, floatiest pulls I’ve ever seen were thrown quite IO but in a medium-strength right-to-left wind. They effectively have a big angle of stall into the wind and get pushed up high, but they still die forwards because their ‘direction of travel’ is, in a sense, to the right, even as they curve left to an observer on the ground.
It isn’t easy to pull like this. You might decide it won’t work for you. Perhaps it’s too windy where you play to control a disc at that height, or perhaps you don’t have the power to get it up there and still get 65-70 yards out of it. But I’m surprised by the number of top teams whose pulls are constantly caught and centered before the defense arrives. If you have someone with a strong enough arm, try practicing this throw. It’s hard to think of a much worse situation for the offense than misreading one of these and catching a disc while running away from their cutters, facing the back of the endzone, with the defense over their shoulder.
Even if that extra height brings the risk of drifting out of bounds, it’s worth the occasional brick to try and pin a team in their own end zone. This fits well with the general suggestion to pull corner to corner, to avoid giving up short field on a missed pull. If I pull from the left corner, aiming for something like Koss’ trajectory above, then the two places I can miss are both quite late in the throw: either too much OI and it goes out near the cone, or too much float and it drifts out of the left side of the field. This is nowhere near as risky a huge IO pull that goes out and (hopefully) back in. With the S-curve pull, 90-100% of its flight will be over the pitch.
Finally, a disclaimer. All the above is much simplified. But where there’s a general left-to-right curve about a throw, it will tend to die more forwards. Not forwards only, and not in a straight line that ignores the continuing effects of aerodynamics, but more forwards than if it were curving right-to-left. That conclusion shouldn’t require a lot of complicated calculus about how the angle of the disc really changes in real time. And that the effect is achievable is amply demonstrated by the video—it is clearly possible to throw a pull that dies forwards. Even if you pick fault with the simplifications in the text, you should probably head out and see if you can make the disc do that anyway!
Blades, rollers, and many other shaped throws are ideal at different times or in different conditions. ↩
Assume RH-BH for all the following also. ↩
Basically, throw it into the wind so that you can catch it yourself. The length of time you can keep it in the air is your score. ↩
With a clockwise (Right-handed backhand) spin. ↩
One other thing I left our for brevity, but can’t resist adding here: the S-curve pull that we’re talking about also has more float for another reason. It is horizontal (i.e. neither OI nor IO) twice. Obviously, the most lift you can get on a disc is when it is flat, so that can only help. If you want to get really technical, the lift on the disc is pretty much the same whether it’s horizontal or not, it’s just that some of the lift is wasted pushing sideways when the disc is not flat. So while it’s sometimes true that more lift means more drag, having the disc horizontal means more useful lift and no additional drag. ↩