F2D Proto Speed muffler rule change approved

Makes use of mufflers optional for speed event

Mike Hazel proposed a change to the Northwest F2D Proto Speed rules.

In voting that occurred between Aug. 26, 2013 and Sept. 26, 2013, the proposal was approved. The voting was unanimous; there were no votes against the proposal.

The rule change makes use of mufflers optional beginning with the 2014 Northwest competition season.

Summary of proposal:

Amends rule No. 4 to read:
Use of muffler is optional. If muffler is used, it must be a legal F2D unit; otherwise, no other exhaust extensions are allowed.


This proposal was offered to help make the event easier to participate in.  It could be argued that the mufflers serve minimal purpose in quieting the engines.  Also, the mufflers, if damaged or lost from the original engine, can be difficult to replace or repair.  Eliminating the mufflers did not obselete any current equipment.  It has also been suggested that the newer engines with smaller muffler outlets may be more powerful than older engines.  If this is so, then eliminating the muffler may make more engines competitive.

The rule change is effective for the 2014 season and applies to all Northwest contests unless specified otherwise by contest organizers.

Voting was conducted as per the process described onFor details on the Northwest rules process, the Northwest Rules page.

2014 NW F2D Proto rules
New language in red; deleted language in strikeout


1. PURPOSE: This event is intended for all fliers and pit crews interested in a simple Speed event which uses unique airplanes of a set wing area and profile fuselage, that is restricted to FAI F2D-legal engines.

2. All AMA control-line unified speed rules apply, except as follows:

2.1. Airplane and the entire control systems shall undergo a pull test of 24G. Maximum model weight shall be 23 oz.
2.2. Lines are .014 solid music wire.Wire material shall be the AMA-required ASTM A228M spec wire. Minimum length is 52' 6" measured from the center of the handle to the center of the fuselage.
2.3 Minimum wing area not including the stabilizer and elevator shall be 100 square inches.
2.4 Airplanes must have a vertical tail fin.
2.5 Airplanes must have a canopy. Wood canopy is allowed but must have a colored outline defining the shape.
2.6 Airplane must have a two wheel landing gear with minimum diameter wheels of 1 inch. Wheels must be spaced at a minimum of 2 -1/2" apart.
2.7 Airplane finish must include a colorful pattern or be painted a solid color. No all-clear finishes will be allowed.
2.8 Airplane must have external controls, the centerline of the bellcrank may be centered inside the fuselage but the bellcrank must be exposed when deflected.
2.9 Terminations of the lines to a bellcrank must be double loop construction when used with a metal-to-metal contact.

3. Engine: Any design or make of piston glow F2D -legal engine is allowed, maximum engine displacement is limited to .1525 cubic inches (2.5 cc) . Modifications are limited to removing material from the engine only. (Diesel legal F2D engines are not allowed)

4. Muffler: A legal F2D muffler must be used on the engine. No modifications are allowed to the muffler except to bring older mufflers to current specifications. Mufflers F2D-legal in 2010 will be allowed until Dec. 31, 2011.Use of a muffler is optional. If a muffler is used, it must be a legal F2D unit; otherwise no other exhaust extensions are allowed.

5. Fuel tank: Any design of fuel tank is allowed, including pressure systems.

6. Fuel: Glow fuel shall contain a maximum of 10 percent nitromethane with 20 percent lubricant and the rest methanol. Glow fuel will be supplied by the contest management.

7. Timing: Timing will begin from the release of the model and end after eight (8) full laps have been completed. The pilot will have 1-1/2 laps after release to get into the pylon.

8. Flying handle: Adjustable handles are allowed.


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This page was upated Sept. 26, 2013