# Why can't there be more than 4 anti-shock bodies on each wing?

Most airliners have 3 or 4 shock bodies to reduce wave drag. But why can't there be more anti-shock bodies per wing?

• why can't who said that? – Federico Aug 24 '15 at 11:56
• Which aircraft do you think would benefit from more ASB than it already have, and why? – mins Aug 30 '15 at 0:05
• This is a perfectly good question, with a perfectly good answer. Question: Is there a reason why aircraft seem to be limited to a certain number of anti-shock bodies that can be placed on a wing? Answer: Not in principle, but constraints keep the number down. There was no reason to vote the question down. – Daniele Procida Aug 1 '17 at 8:57
• @DanieleProcida the question in your comment is not the question being asked. "why can't" assumes that an impossibility exists and is well known, your version doesn't. And at the time OP asked several questions always starting with "why can't", prompting users to edit their posts first, explain them why it was not a good way to ask later, and downvote at the end. – Federico Aug 1 '17 at 11:20

There is no reason to limit the number of anti-shock bodies to 3 or 4. In most modern aircraft, the anti-shock bodies are the flap track fairings which usually house the flap mechanisms.

As such, their number is determined by among other things, the wingspan, the size of control surfaces and the number of actuators required for their actuation etc. This usually limits their number to around 4 due to weight and other considerations.

However, there is no reason there should only be 3 or 4 of them. For example, the Antonov An-225 Mriya has a whole lot of them.

Source:www.avioners.net

There can be, as aeroalias already demonstrated.

However, it would not be better.

Transsonic flow behaves strangely. It cares more about the total cross-section than its distribution. So for the wave-drag reduction it does not matter much whether there are two larger or many smaller anti-shock bodies.

However more anti-shock bodies with the same total cross-section have more surface area and higher surface area causes more friction drag. So more anti-shock is not advantageous.