Disc Flight Ratings Chart

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Re: Disc Flight Ratings Chart

Postby Banzai » Thu May 07, 2009 8:02 am

Just curious ... why is the power requirement for the OLS a 5 and the power requirement for the OLF a 4? Also, any word on adding discmania?
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Re: Disc Flight Ratings Chart

Postby smarkquart » Thu May 07, 2009 10:05 am

Blake_T wrote:
interested in feedback and comments. keep in mind the ratings are targeted with two things in mind: 1) this chart is meant for players with less than 425' of power and 2) the discs were mainly evaluated at the speed ideal for their designed characteristics.



Just a couple of comments about the Striker and Riot. Based upon what I throw, which I believe is close to what you have described, I have seen the Striker as -0.5, 2.0, 5. Not a huge deviation but I find the Riot far more stable than the Striker, more like 0.0, 3.0, 5. For the almost everything else I agree with your chart and it has been incredibly handy trying to compare discs across different manufacturers.

A few weeks ago I was in and bought the Core, Vision, Riot, XXX, and Striker and Charlie said he would like to hear what I thought of them, so I have been out throwing them quite a bit (at least everything but the Vision because I lost that the second day I had it).

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Re: Disc Flight Ratings Chart

Postby Blake_T » Thu May 07, 2009 7:10 pm

Just curious ... why is the power requirement for the OLS a 5 and the power requirement for the OLF a 4?


because the OLS is supposed to be used as a (fairly) straight driver. it requires a 325'+ power throw to get it to fly with its -1.5/+3 characteristics.

the OLF is a moderately overstable driver. it only requires 275' of power to get its intended flight path, thus it is power level 4.

the flight path of an OLF doesn't change much from 275' to 325', but an OLS will have a very different flight path when thrown with 275' of power vs. 325' of power.

e.g.
OLF @275' = HSS 0 LSS +3
OLF @325' = HSS 0 LSS +3
OLF @350' = HSS -0.5 LSS +3

OLS @275' = HSS 0 LSS +3
OLS @325' = HSS -1 LSS +3
OLS @350' = HSS -1.5 LSS +3

make sense?

Just curious ... why is the power requirement for the OLS a 5 and the power requirement for the OLF a 4? Also, any word on adding discmania?


GGGT is working on getting discmania. if/when that happens, yes.

Just a couple of comments about the Striker and Riot. Based upon what I throw, which I believe is close to what you have described, I have seen the Striker as -0.5, 2.0, 5. Not a huge deviation but I find the Riot far more stable than the Striker, more like 0.0, 3.0, 5. For the almost everything else I agree with your chart and it has been incredibly handy trying to compare discs across different manufacturers.


interesting feedback. the riots we threw required more speed to get the turn but turned way more than the striker. the strikers we threw only turned over into the wind and only when dan threw them with 430'+ power into the wind. in calm conditions they were pretty much hss 0. the +3 LSS rating for the striker i got was based upon relativity more than anything and averaging out different flight paths.

we only threw riots and strikers from a single run that were fairly close together in weight.
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Re: Disc Flight Ratings Chart

Postby smarkquart » Thu May 07, 2009 9:02 pm

Blake_T wrote:

interesting feedback. the riots we threw required more speed to get the turn but turned way more than the striker. the strikers we threw only turned over into the wind and only when dan threw them with 430'+ power into the wind. in calm conditions they were pretty much hss 0. the +3 LSS rating for the striker i got was based upon relativity more than anything and averaging out different flight paths.

we only threw riots and strikers from a single run that were fairly close together in weight.


I played three more rounds today at Bassett with both the Striker and Riot as my main drivers. I can most definitely chalk up these differing results to the way that I play (I drive about 350') but here is what I saw:

The Striker, for good or bad, held whatever line it was launched on and was easy to turn over if I did not add a touch of hyzer to it. Its best shot is a slow right turn where it does not fight back into a fade and then slowly settles onto the ground with no roll or skip. I am taking my Monarch out of my bag because of what I can do with this disc. My Riot needed a little more help into a turnover but it was not much of a struggle. However, unlike the Striker where it stayed on that line, the Riot always fought back with a soft fade at the end. Several drives off of Hole #8 at Bassett, with the big tree to the right, had some of the most beautiful S-Curves I have ever seen, several times parking under the basket.

Most definitely I could have fluky discs as they are the only ones of these names I have and do not have others to compare them against. I just thought I would pass along a little more data because I am suddenly hooked on these discs. I will be throwing them a lot so I can have them dialed in for the Majestic.

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Re: Disc Flight Ratings Chart

Postby Jesse B 707 » Fri May 08, 2009 7:10 pm

im guessing you guys tested domey (172+ yellow or clear) strikers cuz to me the #s sound about right on for those. my flat 170ish merlots and purples definitely have a good deal less HSS than my domey ones. at 380 or so of power i can flip em up from 15+ degrees of hyzer or from flattish to a nice anny angle without putting too hard of a pull on em, but maybe my form isnt quite as clean as i think it is :?
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Re: Disc Flight Ratings Chart

Postby Jeronimo » Wed Jul 01, 2009 1:05 pm

Striker and Riot having same range potential? I don't know if I believe that... Striker seems more a 4.5 to me. My Riots Definitely deserve the 5 but not my strikers.
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Re: Disc Flight Ratings Chart

Postby Donkeypuncher » Mon Jul 06, 2009 3:49 pm

Why are no discmania discs listed on the chart? I know a few of them have been out longer than a lot of the newer discs listed.
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Re: Disc Flight Ratings Chart

Postby JimW » Mon Jul 06, 2009 3:55 pm

GGGT doesn't carry Discmania (I think DGV is the only place that you can order them from) so Blake and Dan don't have them around to test out.
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Re: Disc Flight Ratings Chart

Postby Blake_T » Wed Jul 15, 2009 10:22 pm

Why are no discmania discs listed on the chart? I know a few of them have been out longer than a lot of the newer discs listed.


i've never owned a discmania disc, nor had any at my disposal to throw for the chart.
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Re: Disc Flight Ratings Chart

Postby gator » Sun Aug 30, 2009 6:51 am

Wait are you the Blake that calls me about filling my orders at GottaGoGottaThrow? Small freaking world
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Re: Disc Flight Ratings Chart

Postby Solty » Sun Aug 30, 2009 7:41 am

gator wrote:Wait are you the Blake that calls me about filling my orders at GottaGoGottaThrow? Small freaking world


that is he :)
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Re: Disc Flight Ratings Chart

Postby Blake_T » Tue Sep 01, 2009 10:54 pm

Wait are you the Blake that calls me about filling my orders at GottaGoGottaThrow? Small freaking world


yep.
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Re: Disc Flight Ratings Chart

Postby discspeed » Fri Oct 16, 2009 8:01 pm

Nevermind, I just figured out the question I was going to ask.
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Re: Disc Flight Ratings Chart

Postby discspeed » Fri Oct 16, 2009 8:16 pm

I think the Boss should have a higher LSS due to its greater speed. It has a much more dramatic LSS than the Destroyer (both rated 4). Also, the Orc and Boss are my 2 main D drivers and the difference between their respective LSSs is definitely greater than .5. IMO the Boss should be 4.5 or perhaps even 5 (especially the Champs). I also think the XS is given too much range for a fairway type driver. This would really confuse me if I had never thrown one before and bought one (especially considering the Z has got to be the most popular version).
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Re: Disc Flight Ratings Chart

Postby JHern » Sun Oct 18, 2009 5:17 pm

I've spent a lot of time thinking about the flight ratings charts, and how complicated a topic it really is to rate the flight characteristics of a disc. Here is my take on it presently, from a physical point-of-view. It is interesting to think about how this can be made more quantitative. By quantitative, I mean the potential for taking numbers from a ratings chart and doing a physical simulation of the disc's flight to predict its behavior under a number of conditions. This is the future Blake, and I think we might be able to collaborate on this, and perhaps be the first one's to do it well.

It seems to me that there are three separate physical phenomena that occur in a disc's flight:

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1. Disc Drag: This is the aerodynamic drag on the disc due to its displacement of the surrounding air, and tends to decrease the speed of the disc in flight. Disc flight is typically in the turbulent flow regime, so that the drag is proportional to the square of the disc speed. The rule of thumb is: if you throw the disc with twice the speed, you get four times the aerodynamic drag.

Drag force is a function of the shape of the disc, nose angle, and speed alone. Drag force is completely independent of the disc mass. The drag typically increases in proportion to its cross-sectional area projected along its flight trajectory. If the disc's nose angle changes, then so too will the cross-sectional area of the disc.

Off-axis torque, OAT, is induced when the disc has a component of spin about an axis that isn't exactly parallel to its axis of symmetry. This causes the disc to wobble, and creates a pocket of turbulent air around the edge of the disc that tends to cling to it instead of flowing smoothly past the disc. This causes the effective cross-sectional area of the disc to increase.

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2. Disc Lift: This is the "wing" effect of the disc in flight, an aerodynamic force that causes the disc to lift upward and fight against gravity to remain in the air.

The lift force is approximately directed along the axis of symmetry of the disc (if the disc is laying on a flat surface, the axis of symmetry will point directly upward at right angles to that surface). It increases in proportion to the square of the disc speed, the planform area of the disc (which differs little from pi times the disc radius squared), and a lift coefficient. The lift coefficient is a function of the nose angle (or "angle of attack"). The lift force on the disc in flight is not, however, always directed through the center of the disc. Rather, the center of lift, or center of pressure, can either be in front, or in back, of the disc center (front/back relative to the disc's line of motion). This leads to precession, as discussed next.

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3. Disc Precession: This is what causes the disc to change its hyzer angle leftward or rightward while in flight. This is important, because the disc tends to travel in the direction of its in-flight hyzer angle. Given a clean release (no OAT), for a given nose angle and speed, the disc orientation does one of three things...
A. It fades. Fade is defined here as the disc's natural tendency to increase its hyzer angle while in flight through precession (left for RHBH). b]Fade[/b] is caused by a center-of-pressure/lift that is in front of the center of the disc. I.e., lifting the leading edge of the disc more than the trailing edge causes the disc to precess in a manner that makes it fade.
B. It holds the hyzer angle it is currently on. A disc can hold the line/angle it is on when the center-of-pressure/lift is at the very center of the disc.
C. It turns. Turn is defined here as the disc's natural tendency to decrease its hyzer angle while in flight through precession (right for RHBH). Turn is caused by a center-of-pressure/lift that is behind the center of the disc. I.e., lifting the trailing edge of the disc more than the leading edge causes the disc to precess in a manner that makes it turn.

The disc will typically fade or turn over a range of flight speeds, always fading at low speed and only turning at sufficiently high speeds. At some magic speed the disc is neither turning or fading, but holding the line. It is useful to define a number to the turn, and take fade as negative turn (i.e., in the opposite direction as turn). Then the holding speed is the speed of the disc in flight (for a given nose angle) at which the disc has zero turn (and by extension, zero fade).

The rate of turn, how fast the disc turns or fades for a given nose angle, is inversely proportional to the angular momentum, which is itself proportional to both the disc's mass and shape (moment of inertia) and the rate of spin on the disc. If you increase the spin rate, the disc will turn more slowly. The golden rule is: spin it twice as fast, and it will turn half as quickly in flight.

As mentioned above, the tendency to turn has to do with the center-of-pressure relative to the center of the disc. The center of pressure is the center of the lift force projected onto the disc. It tends to fall along a line parallel to the trajectory of the disc that goes through the center of the disc.

Also as mentioned previously, off-axis torque causes the disc to wobble, and creates a pocket of turbulent air around the edge of the disc that tends to cling to it instead of flowing smoothly past the disc. This interferes with the flow of air around the disc in a way that pushes the center of pressure back and therefore increases the turn.

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So, that's the basic outline. I have written down a set of equations that can be used to simulate the motion of the disc, given the above assumptions and a few more. I'll probably try some simulations soon to see what it looks like.

I think there are some important numbers here. In the chart is the strength of the turn at low and high speed (LSS and HSS), and the power (speed) requirement. To me, one measure of the power requirement could be something like the power (in terms of distance is fine) needed to get a disc to hold a straight line. Speed at zero turn would be even better, but I don't think most players are cognizant of their speeds. Anyways, with some modeling, we could indeed begin to tabulate this kind of information for various discs, but there are many variables that need to be better constrained first...I'll have to think about how to do that in the best way without too much special equipment being required.
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