How to make my iPhone not whoop when I send a message?

I have an iPhone 4S and my sound is on. I want the sound on but the "whoop" is unnecessary and annoying. How do I turn it off?

That 'whoop' sound is what sends the message. When the message leaves your phone casing it breaks through the plastic making a 'whoop' sound. You can't stop the 'whoop'.It's like 'whoop there it is' and the message is gone.

These are some sounds you can't change in the iPhone.
1. Whoop noise you hear after a message is sent.
2. Phone locking sound
3. Phone unlocking sound

Btw, you won't be able to hear these sounds if you have the phone in silent mode.