ASP engine, shutoffs approved for Northwest Sport Race

Northwest racing competitors have approved two rules changes for Northwest Sport Race, effective in the 2018 season.

The proposals were made by Gene Pape and Ken Burdick.

Pape proposed adding the ASP .25 to the list of allowed engines. Burdick proposed legalizing pilot-activated shutoffs.

The vote for these two proposals was unanimous. There were no "no" votes for either proposal.

ASP .25 engine

Northwest Sport Race began in the 1970s as a simplified racing event, and since has undergone an evolution. Beginning in 1980, the only engine allowed was the Fox .35 Stunt. In 2014, the OS .25 LA was added to the list of allowable engines. This rule change makes a third engine available.

The use of the proposed ASP .25 engine was tested during the 2017 competition season. It was allowed to run as a demonstration (no official scores) in the Jim Walker Memorial Spring Tune-Up, and was allowed as an official entry in the Fall Follies. In both cases, the engine appeared to be competitive with the Fox and OS engines.

Here are the specifics of the change:

Amends rule No. 3 to to include the ASP .25 in stock configuration. Exact wording is highlighted in the new rules published below.

Rationale: Gene Pape writes: "The Fox Stunt .35 and OS .25 LA are no longer manufactured.  The ASP .25 is readily available, and of a similar level of power.  By having an inexpensive engine available new, it is hoped that participation in the event may be enhanced."


When Northwest Sport Race began, the rules were written to outlaw any devices that made the airplane more complex to build and operate than a typical sport profile airplane. Such "racing technology" devices as shutoffs, fast-fill systems, hot-glove electrical contacts, etc., were outlawed.

In recent years, the argument has been made that lack of shutoffs creates a safety issue, because pilots can't stop the plane in case of an emergency. It also has been observed that with the aging of participants in the hobby in general, the inability to stop the plane on demand may discouraged participation. The current commercial availability of shutoffs means that newcomers or casual fliers no longer have to build the units themselves.

Here are the specifics of the change:

Amends rule No. 6 to by removing the word "fuel shutoff."

Rationale: Ken Burdick writes: "For increased safety by allowing the pilot to shut down the engine in the event of an unplanned situation during a race, as well as a more predictable landing area for the pitman. Shutoffs are commercially available or can be easily fabricated by most modelers."

Discussion period

A one-month discussion of the proposals was conducted on the Northwest CL Forum. Comments made during that period and since can still be seen there.

Approved 2018 Northwest Sport Race rules
New language in red; deleted language in strikeout


1. Purpose: It is the intent that that this event will provide the novice competitor a beginning racing event, racing with other competitors using similar equipment which is readily obtainable and operates in a basic fashion.

2. All pertinent rules from AMA unified racing rules shall apply, in regard to safety and conduct of races, except as follows.

3. Engines:  The only allowed engines shall be the Fox Stunt .35, and the O.S. LA .25 and the ASP .25, all of which shall operate on suction feed and be in stock, unmodified condition except as follows:
a. “Stock” is defined as absolutely unmodified but making exceptions for needle valve assemblies, engine assembly bolts, gaskets, prop nut, and prop washer(s).  Additionally, intake venturi must maintain original factory stock dimension.
b. No exhaust extensions are allowed except bona fide mufflers that do not increase engine performance.
c. Other: The Fox Manufacturing Co. hemi/stuffer kit modification is prohibited. The O.S. LA .25 may have the rear needle valve assembly post removed, and may use a substitute backplate.  The RC version of the O.S. LA .25 engine may be used, by fixing the throttle in one position.
The ASP .25 may have the rear needle valve assembly post removed.  The RC version of the ASP .25 engine may be used, by fixing the throttle in one position.  The ASP .25 may have the R/C carburetor replaced by a control-line style venturi with a bore not larger than the original  R/C carburetor (6mm or .236”).

4.1. Aircraft: The model shall be built from, or an exact duplication of, a commercially manufactured kit. In the case of obscure or rare kits, some documentation, such as a set of plans, may be required by the contest director for confirmation of the airplane's kit status. Kits need not be in current production or distribution to qualify.
4.2. Models must be of profile fuselage type, and must conform to the general profile definition. The model must have a minimum fuselage length of 24" when measured from the propeller thrust washer face to the leading edge of the movable elevator surface.
4.3. The minimum wing area shall be 300 square inches. The wing must have a minimum thickness of 1 inch when measured at any point along the span, with the exception of the last two inches before each wingtip.
4.4. All models must have a canopy, horizontal stabilizer, elevator and vertical fin. Models must have a fixed landing gear with a minimum of one wheel, 2 inches in diameter or larger.
4.5. Modifications: Major changes to the kit design such as clipped wings, shortened fuselage, partial omission of the tail assembly, etc., are prohibited. Reinforcement of the nose and engine mount areas is permitted. Landing gear location and construction are entirely optional from what may be included in the kit, except as specified in section 4.4.

5. Fuel tank: The fuel tank shall be fully external and forward of the wing leading edge, and located on the outboard side of the fuselage. The tank may not be designed so as to cowl the engine. All tank vents are limited to a maximum size of 1/8-inch outside diameter. The tank may not be pressurized, but the vents may be directed forward into the airstream.

6. Prohibited equipment: The following equipment and devices standard to full-race aircraft are prohibited: . These include fuel shutoff, pressure refuelers, fast-fill systems, "hot glove" electrical contact systems, and centrifugal carburetor switches.

7. Pull test: The plane and entire control system shall undergo a pull test of 35 pounds.

8. Lines shall be of a minimum .018-inch diameter, and lines shall be of the stranded type, with a length of 60 feet measured from the handle grip to the fuselage, plus or minus 6 inches.

9. Races: Preliminary heats shall be of 70 laps duration, with one pit stop minimum required. Feature races shall be of 140 laps with two pit stops minimum. All races shall be flown with at least two entrants, and not more than four entrants. At contestants where entrants fly preliminary heats to determine finalists, at least three entries shall proceed to the final races. The decision on the number of final entries shall be made by the event director and made in advance before the start of any preliminary heats.

10. It is assumed that the usual sportsmanship of Northwest modelers will prevail in this event. The event director may disqualify any entrant that is not in keeping with the spirit or intent of this racing event.

FL/jmt9/29/85 //Ed:4/15/93//rev2/12/95//rev:mhballot:1/5/14//p:gp:11/2/17//p:kb:11/12/17//rev:gp-kbballot:1/12/18

For a complete copy of the Northwest Sport Race rules (without the annotations above), and for an explanation of how the Northwest control-line rules process works, see the Northwest Rules page.

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This page was upated Jan. 15, 2018