Standard vs. Expert
Dan,
The airframe and engine passage in the 424 rules is included below.
16.3.1. Airframe.The airframe specifications
for this event are identical to those for Quickie 500
(Event No. 428).
16.3.2. Powerplant
a. Engine.
1) Maximum displacement:0.403 cubic inch.
2) Configuration:Stock, commercially available,
front-intake, side-exhaust.
3) Intake:A single carburetor, as supplied by
the manufacturer of the engine being used,
with a maximum inner diameter of 0.325 inch.
The carburetor shall be fully functional and
shall be stock, except for longevity-enhancing
modifications as follows:
(a) Adjustment screws and idle needle valves
may be held in place with commercially
available thread locker, epoxy, or other adhesives
and safetied with rubber bands, wire, or
plastic ties.
(b) Barrel retaining screws or pins may be
replaced with commercially available screws
or pins of harder material and may be held in
place with commercially available adhesives.
Barrels may be deburred for smoother movement
and may be safetied with rubber bands,
wire, or plastic ties.
(c) Throttle arms may be modified or
replaced.
4) Exhaust system:The engine shall be
equipped with an expansion chamber muffler or
zero-boost muffler as provided by the manufacturer
of the engine being used, and having a single
exhaust outlet with a maximum outlet area
of 0.0621 square inches (equivalent to the area
of a round hole measuring 9/32 inch in diameter).
The distance from the center of the piston
to the centerline of the muffler shall not exceed
2-3/4 inches. The overall length of the muffler
shall not exceed 7-1/4 inches, measured from
the front of the header to the back of the exhaust
outlet. The outside diameter shall not exceed
1-3/4 inches. No modifications to the muffler
are permitted except that the muffler may be
tapped for a pressure fitting to supply pressure
to the fuel system. Tuned mufflers and tuned
pipes are prohibited.
5) Fuel feed:Other than muffler pressure, no
fuel system pressurization is permitted.
6) Power output:Sport Quickie is intended as
an entry-level event for pilots who are new to
racing. As such, it is not a suitable event for the
use of engines that come with tuned mufflers or
otherwise are capable of turning a stock 9 x 6
APC propeller at over 16,500 rpm on the
ground. If engines more powerful than this are
to be used at a contest, the contest should be
sanctioned as Quickie 500 (Event No. 428), not
Sport Quickie.