Rules for
Northwest B Proto Speed

PURPOSE  : To provide a affordable, basic & simple traditional C/L speed event that any modeller of reasonable ability can build and fly. The event is a simplified version of 21 Proto but using a profile fuselage and a standard low tech engine. The use of one engine choice is designed to provide close competition in a reliable and inexpensive manner at speeds somewhat comparable to the glory days of Proto Speed in the 1950s.

AIRPLANE:   Minimum 125 sq. in wing with a minimum 20% Stabilizer. Rudder must be a minimum of 5% of the wing area and mounted in the traditional upright position. Use of a sub rudder is prohibited. Model may use either a full fuselage design or a Profile. Fixed two wheel landing gear with minimum 1-1/2" wheels laterally spaced at least 6" apart. Model must have a canopy with minimum dimensions of 1" high by 3-1/2" long. Canopy may be clear plastic or painted on. The engine can be mounted in any position. Cowling of the engine is optional. Entrants MAAC or AMA license number must be displayed on the upper right hand wing panel with a minimum 1" height.

ENGINE : The event will use a standard OS 25LA engine. There is no restriction regarding engine modification, except that all major components shall be from the original manufacturer specifically for that engine.  Engine parts such as venturi, needle valve system, screws, prop washers, gaskets, etc may be from any source. Use of the muffler is optional.  Only two bladed propellors may be used.

FUEL:  Only contest provided standard 10% nitro fuel shall be used for competition.

LINES:  Minimum length as measured from center line of handle grip to the fuselage centerline is 60 feet.  Only single strand lines may be used.  Two wire control systems shall have a minimum line diameter of .016”, and single wire control systems shall have a minimum line diameter of .026”.

PULL TEST : The model and control system shall be subjected to a 24g pull test.

TIMING :  Timed from takeoff to 14 laps, (1 mile),  standard Proto Speed timing.

All other AMA / MAAC speed and saftey rules shall apply.

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OK, there you have it.  Questions that may come up ...

Do we need another speed event? Well, this one is different with the engine rule, really makes it approachable by anybody.  Our Northwest F2D Proto event is also a good event for speed beginners, but try ordering an engine from Tower Hobbies. This event allows monoline, isn’t that unfair?  Actually the assumed advantage of monoline will be pretty minimal at the speeds these things will go.  Plus these planes will make ideal monoline trainers for those wishing to give that a try.  Like other speed events solid lines are required, where can I get those?  No problemo, just go to the Flying Lines Control-Line Suppliers page and look up MBS Model Supply.  They have solid wire and several other useful items.

Speaking of supplies, Marty Higgs reports that he and Partner will be making available various speed supplies for this event and others.  Items will include lines, control system hardware, tanks, aircraft plans, and maybe even a kit.  Watch the FL classified section for this.

The guys report the designs that have come up with fly great, and the engines are easy to start and tune.  First test results show a Proto clocking in the lower 90 mph range with top end approaching 100 mph, plenty easy to handle!  They also report that the LA 25 engine has lots of torque so it’s happy with a high pitch prop, such as an 8 x 8.

This event will be included at the Salem Speed and Combat meet coming in September, so youse guys have some time to put something together. 

-- Mike Hazel

Business end of a B Proto: The O.S. LA .25

Monoline control system.

Ready to fly!