F2C Urgent Technical Notice

To All F2C Fliers

As you all know, new rules to control noise in F2C were introduced in January of this year. One of the principles of these new rules is that initially only the venturi needs to be changed on the engines, however the rules did not make clear what to do about the supplementary fuel jet fitted on most engines.

This issue has been discussed with Rob Fitzgerald, the F2C Working Group Chairman and Kevin Dodd the CIAM Technical Secretary and the following clarification has been agreed.

The rule states:

4.3 F2C

4.3.4 c) Any interconnecting chamber between the air intake and the induction port of the motor shall have a maximum volume of 1,25 cm3. No leakage is allowed between the venturi and the crankcase.

The following is the clarification relating to the above rule:

The use of a single, round supplementary fuel jet with a maximum diameter of 0.4mm between the venturi and the induction port of the engine is permissible to allow the use of engines and fuel systems designed prior to 01/01/2015.

This clarification, which is effective immediately, has the overwhelming agreement of the F2 Subcommittee.

Peter Halman

F2 Subcommittee Chairman

3rd March 2015