Function of Trailing Edge Battens

[Nygs]

What is the purpose of trailing edge battens on kites? One of the TE battens on one of my kites feels broken. How will this negatively impact performance? Are they just there to reduce TE flutter? Thanks!




----edit---
Ooops thats battens not batons. Thanks Vin

[Vin Stefanelli]

BATTENS!

[munteruk]

Battens do a few things:
1. They stop TE flutter if mounted in the right position
2. They can support a different TE outline
3. They can help ensure that the panel at the TE is flat which can help to reduce drag. I haven't seen hooked TE's on that many kites though so I don't think this one comes up much. Its more of an issue on boat sails with leech lines.

I think you should watch the area with the broken batten for any signs of fluttering during flight. If it isn't fluttering and the cloth looks stable then it may not need to be replaced.

However, if the batten is fiberglass and now has sharp edges within the batten pocket then you probably should either remove it or replace it so that the broken edges don't cut through the cloth.

I'm not convince of the merits of battens on kites. I don't think its been proven that they actually do much (apart from add weight).

[uncleneil]

I'm not convince of the merits of battens on kites. I don't think its been proven that they actually do much (apart from add weight).

Weight?? Maybe the battens add an ounce or 2. Lets be honest now.

[Gigi;)]

They definately reduce TE flutter (and the stuff because of that). Search kite-stuff.org (LightFly 7) posts & vids to see it.

I'm not convince of the merits of battens on kites. I don't think its been proven that they actually do much (apart from add weight).

Weight?? Maybe the battens add an ounce or 2. Lets be honest now.

[munteruk]

Unc:
When you take into consideration the weight of the batten, the weight of the batten pocket and the weight of the tip reinforcements & patches and multiply each by the number of battens then I think it all adds up. I think this extra weight should be justified by a definite performance advantage and to date, I don't think its been demonstrated.

Gigi:
Firstup - full credit for running an excellent kite design website. I like how kite-stuff focusses on kite design without hype from people pushing product. I think some of the ideas there are leading edge.
I wasn't really clear in my first post. I'm most skeptical about battens on the leading edge. Manufacturers claim improved "stability" but it seems too many other variables are changed from year to year to really assess this claim.
As for reducing flutter on the TE, this can be achieved through the scalloping the TE and while this sacrifices a small amount of area it does so without adding weight. I'm still not convinced that the added area maintained through the use of battens sufficiently offets the penalty from the added weight. Have you tried scalloping on your designs?

In addition, battens add to the manufacturing time & complexity as well as making kites a little harder to pack and store. I hope designers can come up with designs that don't need them to fly well. There are already examples out there...

[RickyBobby]

I think they are useless on the trailing edge of a kite.

On the leading edge, they help stabilize the foil shape of the kite and help keep the draft of the kite from wandering around aimlessly, like a lost soul.

Full Throttle!

RB

[Gigi;)]

THX for your comments about my site! I'm really happy to hear that! I'm hoping to see more good post there!

I agree about added weight & other things that you've mentioned...

Even LE battens have their purpose on the kite. They do prevent LE profile "collapsing" too soon (so called stability) at low AoAs and also in some other occasions, for instance in lower wind conditions for the kite, when you fast sine the kite, LE profile can "collapse" for a little when you do a fast "up turn", if you know of what I mean. Battens do help to prevent that as I've experienced on my LF7m kite.

I'm still not sure if it's the combination of not so perfect profile use and/or designed AoA problem...

I'm about to open a topic about that on kite-stuff.org for further discussion... It would be great to hear any good comments!

I'm using the scalloping a little, but it actually does not help much. Maybe a big scallop would help, but it looks ugly for me so I'm not using it... ;) And I'm somehow convinced that in many cases, the TE flutter is because of LE profile distortions (gusts, etc...)...

Probably surpluses of battens are better than minuses, so that they find their space on your kites!

M2C

Gigi:
Firstup - full credit for running an excellent kite design website. I like how kite-stuff focusses on kite design without hype from people pushing product. I think some of the ideas there are leading edge.
I wasn't really clear in my first post. I'm most skeptical about battens on the leading edge. Manufacturers claim improved "stability" but it seems too many other variables are changed from year to year to really assess this claim.
As for reducing flutter on the TE, this can be achieved through the scalloping the TE and while this sacrifices a small amount of area it does so without adding weight. I'm still not convinced that the added area maintained through the use of battens sufficiently offets the penalty from the added weight. Have you tried scalloping on your designs?

In addition, battens add to the manufacturing time & complexity as well as making kites a little harder to pack and store. I hope designers can come up with designs that don't need them to fly well. There are already examples out there...

[sq225917]

i dont know about anyone elses battens, but the ones we use are pretty light, maybe 20 grams a piece.

Best wrap the battens in clear tough 2mm heat shrink,so if you crack one you can see it and replace it,also if you do manage to crack one then it does split into the canopy cloth.

But if you crack on remove it and replace it as it's not doing its job.

LE battens on the Waroo/etc etc definately help support the canopy towards negative AOA making it fly further forward with more depower and speed.

The trailing edge battens really help the aerodynamics out, keeping the canopy flat and tight and flutter free, we tried an extra strut in this position but the batten did the job and was a more elegant solution.

like anything it's a matter of balancing the pro's and cons.