So I noticed in a lot of the threads that people are often disssapointed with some of the discs they recieved because they were either too flippy, or too beefy to get the results they expected. I've experienced the same problems and it's pretty annoying when I fork out money for a new disc, take it out to the field, and realize that it's utterly useless. Then I used the magic of Google to search "is there a way to make discs more overstable?" and found this article: http://www.aerobie.com/Products/Details ... rticle.htm

The link might not work for some, since I'm posting from an iPhone, but if you Google "Tuning long range drivers for desired flight characteristics", you'll find it. I was sceptical that it would work at first, but after spending about 15 minutes bending the wing of an extremely beat-up, super flippy Vulcan, I took it out to the feild to test it. I bent the rim so much that it flew pretty much the same as a Star Max. Serious hyzer from a disc that I had given up on.

After that I "tuned" almost all the discs I had in storage and now I have so many great discs that I'm having trouble justifying buying anything new. Mid-ranges or putters are the only discs that are difficult to modify. Most fairway drivers are adjustable using this method. They just take a little more effort.

Welcome. There are many threads about wing height and dome tuning on this site. I have successfully returned putters and mids to original shape after bent edges from tree collisions. After beating the same disc a lot more i've gotten original flight back even though the flight plate is bumpy just by returning the outside edge to regular height. Tuning new unchanged discs makes them tournament illegal. It is another matter if anyone can spot the difference and prove it. Although Vulcan to Max is such a large change that the edge might be easy enough to notice.

Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.

The consensus here is that dome has little or no effect on under-/over-stability, and instead it is primarily due to the relative "parting line height" (PLH) of the wing. Drivers become understable with wear because impacts bend the PLH downward. Discs left to cool for a longer time in the mold have a higher wing height, and are more over-stable.

What a higher dome can do is increase the aerodynamic lift of the disc (to a point), giving you better glide. But greater lift means that the stability will be more sensitive to nose angle. So flattening a dome will give you an easier to control disc, but some domey discs will give you the greatest distance potential (e.g., poppy top Destroyers).

Dome while high can stop the disc short in headwinds and significantly change the outside edge height. So some dome heights are confusing and contradictory. Some discs are more overstable with a higher dome and others vice versa.

Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.

JR wrote:Dome while high can stop the disc short in headwinds and significantly change the outside edge height. So some dome heights are confusing and contradictory. Some discs are more overstable with a higher dome and others vice versa.

I disagree, the ones that are over-stable when domed have a high PLH, which is the root cause. The dome simply amplifies the sensitivity to nose angles, making it even more over-stable for nose up angles of attack.

How can it be legal to tune an Aerobie but illegal to tune other discs?

If a disc were named the "fish" would it be legal to tune it?

Anyway, how could anyone tune a disc with the degree of precision it would take to make the disc fly predictably?

I tend to think that tuning is not modifying and so it wouldn't be illegal either. Also it's impossible to know if a disc is tuned or if it just happens to have different PLH than most of it's kind (Properly tuned Epic is easy to spot of course).

I was reading in another article that domier discs fly slower and that causes them to seem more overstable, since the slower a disc flies, the more HSS it seems to have. The flater topped version of the same disc flys faster (I'm thinking domey topped vs. "Vulcan" topped destroyers) is less HSS, since it's moving faster. Sounds reasonable to me...

It IS possible to tune a disc for a consistent flight. In fact it's pretty darn easy to do. Just bend evenly around the disc like in the picture. (link in first post) Some of the old discs I worked on we're warped from tree collisions and after tuning, they were straight again and flew like new. If you don't believe it, just take the crappiest disc you have and give it a try. DX and pro or r-pro plastics are super easy to bend so do it gradually and gently at first.

I did read that it's illegal once you tune the discs, but the idea that someone would glance over at the disc you're throwing and say, "hey! That Destroyer looks like the wing is one millimeter higher than factory specifications! I demand an official ruling over here!" seems unlikely in the extreme. Also, it's ridiculous that it even would be illegal. The modification rule would be more for if you stuck weights in the discs or something IMO. If not, then every time my opponents disc hit a tree I could say its been modified to fly less overstable than when it was PDGA approved. :p

Peter172 wrote:I did read that it's illegal once you tune the discs, but the idea that someone would glance over at the disc you're throwing and say, "hey! That Destroyer looks like the wing is one millimeter higher than factory specifications! I demand an official ruling over here!" seems unlikely in the extreme. Also, it's ridiculous that it even would be illegal. The modification rule would be more for if you stuck weights in the discs or something IMO. If not, then every time my opponents disc hit a tree I could say its been modified to fly less overstable than when it was PDGA approved. :p

I agree it's unlikely but rules today encourage this I wonder if you'd have any friends left after that tho.

801.02 DA disc that is questioned by another player or an official is illegal unless it is subsequently approved by the Director.

JR wrote:Dome while high can stop the disc short in headwinds and significantly change the outside edge height. So some dome heights are confusing and contradictory. Some discs are more overstable with a higher dome and others vice versa.

I disagree, the ones that are over-stable when domed have a high PLH, which is the root cause. The dome simply amplifies the sensitivity to nose angles, making it even more over-stable for nose up angles of attack.

That is the case for poppy top Flashes i think but what about flat top Star Katana that is so taut in the flight plate with so little plastic in there and tension that also pulls up the PLH? It also changes the ratio of how much air is displaced over (less height and distance for the air to travel around) and under PLH vs a domey lower PLH domey Katana in other plastics. So the lift, precession and drag at least change in a flat vs domey Katana both of which have high PLH. I have not checked if there are Star Katanas that are identical below the PLH to domey Katanas of other plastics so ceteris paribus could not occur if there are differences in the bottom part of the disc.

Take a Nuke and get a flatter top and you'll get one understable sucker. I have not made a direct side by side comparison but i think that flatter Nukes have a lower PLH by a mm or less. But the difference in flight i huge so details count. I'm not sure that every disc has been explored in enough measuring accuracy to say for sure that in all cases jut the PLH makes the difference. Other factors can make a dent in the flight variations of discs.

I have noticed that Rocs that have more dome tend to become more understable. Not looking at them any more closely than thinking they have similar PLH to flatter Rocs it would seem that either i have not spotted the PLH height correctly or PLH can change in other ways than with the dome height alone. And if that happens the other shapes might explain differences in stability and other factors.

Mark: It is easy to tune discs to fly just like you like to because going in small increments is not hard and discs tune back if you went too far in one direction in the tuning process. Discs hold the tuning surprisingly well. Longer than the initial break in period of base plastic mostly. medium to high grade plastics last a very long time in the tuned shape. You are correct in that even the Aerobie Epic is illegal to tune per rules if i've understood the rule correctly. No matter what the text that Aerobie has written on the package of that disc about tuning to change the stability. The disc is in the intended shape when new only. Tune that and you lost the competition legality right?

Varsi tuning is very much changing the attributes of the disc away from the factory specification. Thus it is tournament illegal to my knowledge. The problem for the manufacturers is that they can't meet the intended shape always and the trouble for the customer is to know what is the factory specification that was intended. And i'm not sure at all if the rules really in all cases allow tuning of a disc back to factory spec if the disc is off. Because even though you could get a reply from the manufacturer about what the disc should be like can you measure the disc accurately enough to make sure that after tuning it is in the factory specced condition. The lucky thing for the manufacturer is that even the off pieces are rules wise in factory specification no matter how mangled they are. The rules allow for a wide variety of manufacturing errors to be called to be within specs. You need a hole in the disc or something other major to make the disc illegal.

Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.