Didn't want to hijack the 29 inch racquet thread too much, so I thought I'd move my inquiry to a new thread.
If anyone knows or can explain the physics of racquet length, why is it that 27 is the standard length for racquets? Some players go up to 27.5 and 28 inches, and a few I've heard of use 29 inch frames. So I was wondering why no one goes below 27 inches? Why are there no 26 or 26.5 inch frames? What would be the advantages/disadvantages to using such a racquet?
Shorter racquets have their advantages: Greater hittingweight and therefore greater inherent power.
Hittingweight is the proportion of a racquet's static weight that is represented at a particular impact location. At the balance point the hittingweight equals the static weight. But the further you go towards the tip, that proportion, and thus the hittingweight, declines. And with it goes the power, as hittingweight is almost directly proportional to inherent power.
So if you have a 27" racquet and a 26" racquet, both with identical specs, the 26" racquet will have higher hittingweight and more power at an identical impact location (like the center of the stringbed). Observe
:
27" racquet (340g/32cm/330 SW)
hittingweight in center of stringbed: ~ 172 grams
26" racquet (340g/32cm/330 SW)
hittingweight in center of stringbed: ~ 192 grams
This difference is really quite large; it's about the same as adding 11 grams of lead to 12 o'clock on the 27" racquet (equivalent to 376 SW). You can imagine the power, stability and plowthrough you'd have with so much lead.
However, shorter racquets are shorter and so therefore have less reach. If you think having an inch-shorter arm is a big disadvantage then short racquets aren't so hot.
Also, if we look back at the two racquets above, we see that the impact location (in the center of the stringbed) is one inch further from the hand on the 27" racquet. Because the racquet is swung in an arc on most strokes, the racquet is moving faster the further away from the hand. This means that the center of the stringbed is moving faster on the 27" racquet than on the 26" racquet - about 1.7 mph faster on a college-level (65 mph swingspeed) forehand.
Obviously a faster moving racquet has more energy and hits the ball harder. But, it turns out that this faster movement is almost equally cancelled out by the lower hittingweight of the 27" inch racquet, resulting in nearly identical speed of shot between the two racquets. However, because the 26" racquet is moving slower at the impact location, it will generate less spin then the 27" racquet - about 10% less.
So on groundstrokes and serves the 27" and 26" racquets will generate the same speed of shot, but the 27" racquet will generate slightly more spin. However, recall that the 26" racquet has much higher effective hittingweight. This will translate as more plowthrough and stability, and more comfort. The 26" racquet will hit a very similar ball as the 27" one, but will really
brutalize it.
This will be especially nice at the net, where you're not swinging fast and don't really need spin that much. At slower swingspeeds the contribution of hittingweight on shot speed is much higher, so your volleys will be more powerful (maybe 2-3 mph faster) with the 26" racquet. Also, because the impact point is closer to your hand, you may have better control and accuracy, but less reach.
Finally, there
are 26.5" and 26" frames. The poster Travlerajm has been shortening frames for several years. Shortening a frame 1/2" lowers the swingweight by about 24 units. So it's possible to add a huge amount of lead tape to the head after cutting, which increases the frame's stability tremendously. Trav likes to remove a half-inch and then lead it up to around 365 SW. In terms of hittingweight, this is equivalent to a 27" frame with swingweight of 390. Very sturdy frames. I recommend searching for his threads about shortening frames; that's where I learned most of the stuff I'm telling you now.
However, it's not necessary to go to super-high swingweights - I play with a 26.5" frame that's leaded up only to return the specs to match the frame at its original length. So comparing my frame to the stock frame is very much like comparing the 27" and 26" frames in the example above, but not as extreme because I've only removed half, rather than a full, inch.
Maybe I lose a little bit of pop and spin on serve, but I prefer the shorter racquet for all other strokes and find it especially awesome at net: more maneuverable, more stable, more powerful than at standard length.
