user29042: i struggle to figure out the max payload for the RF24 Network library without payload fragmentation.
It uses a NetworkHeader with the Attributes from_node, to_node, id, type and reserved.
This must be send to and lowers the amount of Bytes of the payload.
Can any one tell me how many Bytes I can write without sending two packages?

user28768: According to the source code:
const static unsigned int max_frame_payload_size = MAX_FRAME_SIZE-sizeof(RF24NetworkHeader);

that would be 24 bytes. Maximum lenght of payload for NRF24L01+ is 32 bytes and the RF24NetworkHeader seem to be 8 bytes long. So you can send up to 24 bytes in one package.
EDIT:
Here is the stripped RF24NetworkHeader declaration code from which can be seen sizeof(RF24NetworkHeader) is 8 bytes.
struct RF24NetworkHeader {
  uint16_t from_node;           // 2 bytes
  uint16_t to_node;             // 2 bytes
  uint16_t id;                  // 2 bytes
  unsigned char type;           // 1 byte
  unsigned char reserved;       // 1 byte
  static uint16_t next_id;      // static member doesn't count for sizeof()
  RF24NetworkHeader() {}
  RF24NetworkHeader(uint16_t _to, unsigned char _type = 0): to_node(_to), id(next_id++), type(_type) {}
  const char* toString(void) const;
};


29042: <p>i struggle to figure out the max payload for the RF24 Network library without payload fragmentation.
It uses a NetworkHeader with the Attributes from_node, to_node, id, type and reserved.
This must be send to and lowers the amount of Bytes of the payload.</p>

<p>Can any one tell me how many Bytes I can write without sending two packages?</p>
 28768: <p>According to the source code:</p>



<pre class="lang-cpp prettyprint-override"><code>const static unsigned int max_frame_payload_size = MAX_FRAME_SIZE-sizeof(RF24NetworkHeader);
</code></pre>

<p>that would be <code>24 bytes</code>. Maximum lenght of payload for NRF24L01+ is 32 bytes and the <code>RF24NetworkHeader</code> seem to be 8 bytes long. So you can send up to 24 bytes in one package.</p>

<p><strong>EDIT:</strong><br>
Here is the stripped <code>RF24NetworkHeader</code> declaration code from which can be seen <code>sizeof(RF24NetworkHeader)</code> is 8 bytes.</p>

<pre class="lang-cpp prettyprint-override"><code>struct RF24NetworkHeader {
  uint16_t from_node;           // 2 bytes
  uint16_t to_node;             // 2 bytes
  uint16_t id;                  // 2 bytes
  unsigned char type;           // 1 byte
  unsigned char reserved;       // 1 byte
  static uint16_t next_id;      // static member doesn't count for sizeof()
  RF24NetworkHeader() {}
  RF24NetworkHeader(uint16_t _to, unsigned char _type = 0): to_node(_to), id(next_id++), type(_type) {}
  const char* toString(void) const;
};
</code></pre>
