P-40 rules

Someone asked about the P-40 engine rules.
Below are the entire rules for Northwest P-40 Stunt.
Note, as Dan did in an earlier post, that these are the Northwest rules. The event is done differently elsewhere.
These are the rules to be used in this weekend's Fall Follies. Simple as dirt (not THAT Dirt).
--jt

NORTHWEST P-40 STUNT

1. PURPOSE: This event is intended to provide a competitive opportunity for fliers of all ability levels using profile-fuselage airplanes limited to .40 engine displacement.
2. All rules for AMA precision aerobatics shall apply except as follows:
3. Airplane: Any profile airplane is allowed.
3.1. The engine may be mounted in any configuration — side-mounted, upright or inverted.
3.2. Doublers or triplers and cheek cowls are allowed, including faired spinners, but the fuselage must meet the “profile” definition of 3/4” thickness by the trailing edge of the wing/flap hinge line, and the engine must be fully exposed from lugs to plug.
4. Engine: Any engine up to .40 size, including four-strokes (no 60% rule for four-strokes).
3.1. Mufflers are allowed, but not mandatory. Any exhaust system is allowed.
5. Lines: Line sizes must follow AMA Precision aerobatics guidelines
6. Pattern: Standard AMA Precision Aerobatics pattern.
7. Appearance: There are no appearance points.
8. Skill classes: Whenever possible, competition shall be divided into two skill divisions, as follows:
8.1. Expert: Any flier may enter this class.
8.2. Sportsman: PAMPA expert-class skill fliers may not fly in this class.

jmt/mwh/dg/12-02/FL/186 ballot
Northwest rules are coordinated and sponsored by Flying Lines, the independent voice of Northwest Control-Line model aviation. Subscriptions cost $14 per year. Flying Lines, 2456 Quince St. Eugene, OR 97404, [email protected]

John Thompson

>NORTHWEST P-40 STUNT
>
>1. PURPOSE: This event is intended to provide a competitive
>opportunity for fliers of all ability levels using
>profile-fuselage airplanes limited to .40 engine
>displacement.
>2. All rules for AMA precision aerobatics shall apply except
>as follows:
>3. Airplane: Any profile airplane is allowed.
> 3.1. The engine may be mounted in any configuration —
>side-mounted, upright or inverted.
> 3.2. Doublers or triplers and cheek cowls are allowed,
>including faired spinners, but the fuselage must meet the
>“profile” definition of 3/4” thickness by the trailing edge
>of the wing/flap hinge line, and the engine must be fully
>exposed from lugs to plug.
>4. Engine: Any engine up to .40 size, including four-strokes
>(no 60% rule for four-strokes).
> 3.1. Mufflers are allowed, but not mandatory. Any exhaust
>system is allowed.
>5. Lines: Line sizes must follow AMA Precision aerobatics
>guidelines
>6. Pattern: Standard AMA Precision Aerobatics pattern.
>7. Appearance: There are no appearance points.
>8. Skill classes: Whenever possible, competition shall be
>divided into two skill divisions, as follows:
> 8.1. Expert: Any flier may enter this class.
> 8.2. Sportsman: PAMPA expert-class skill fliers may not fly
>in this class.

>
>
>Well, that settles it DAN...The "OTBP" IS legal for P-40. See you saturday!

Some contests in the midwest specify a side-mounted engine, which strikes me as being in the spirit of the event. Others disagree. Skill classes are sometimes flown, sometimes not. Other than that the rules are pretty much the same as the NW rules.

Is the 3/4" profile fuselage thickness rule at the TE a little on the big side? Most people don't run their doublers back that far, and 1/2" or 5/8" is a pretty standard thickness for the balsa only. Just asking...

I was wondering about that dimension too.

3/4" is a pretty fat fuselage for a profile.

The 3/4 inch max width is part of the AMA profile definition for slow combat, slow rat, rat, and carrier. This is including the plywood doublers. The AMA definition does allow for upright and inverted engines.

>The 3/4 inch max width is part of the AMA profile definition
>for slow combat, slow rat, rat, and carrier. This is
>including the plywood doublers. The AMA definition does
>allow for upright and inverted engines.
>
>Jim

More on the AMA rules for profiles....

The AMA rules specify dimensions for several classes of models, but NOT for any stunt models. So I guess the definition that was used (3/4" at the flap hinge line) is as good as any other for the P-40 models.

Only one kink: the AMA rules also specify that

Cheek cowls may extend from the prop drive washer
to a point 25 percent of the root chord back of the
leading edge at the root, and may be faired in.

But, again, only for the events mentioned, there are also maximum cheek cowl thicknesses, too.

Oh, well.....

I've got an ARF Cardinal on the way.

Is this airframe P-40 legal?

Seems like it would be if the engine was not bigger than a .40.

I'm planning a ST .46 to start with, but the engine change is easy with the engine clamps.

Cy

LAST EDITED ON Oct-11-04 AT 12:43 PM (CDT)
 
The ARF Cardinal would be legal for Northwest P-40 if it meets the profile definition quoted above and has a .40 or less engine. There is no builder-of-the-model rule.
--jt

>
>I've got an ARF Cardinal on the way.
>
>Is this airframe P-40 legal?
>
>Seems like it would be if the engine was not bigger than a
>.40.
>
>I'm planning a ST .46 to start with, but the engine change
>is easy with the engine clamps.
>
>Cy

John Thompson