IMPBA DISTRICT FOUR
MOST POPULAR LARGE SCALE GAS
Spec engines will be the Zenoah G260 PUM only. You may run a stock unmodified 257 or the original 644 with choke carburetor. No internal modifications allowed. Recoil pull start must be the primary method of starting. EZ start and pulleys acceptable. Length shall be a maximum 56 inches and a minimum 47 inches. Width shall be a minimum 22 inches. Boats shall have front or rear cockpit with driver figures from the 1950’s-1970’s era, no cartoon characters. A minimum 50% of the gas engine must be covered with either a cowling or period correct fake engine.
GAS SPORT HYDRO
District Four runs the LSG36 Sport Hydro class. Maximum engine displacement must not exceed 36.0 cc. Some racers may run the smaller LSG27 engines in this class as this is allowed. The Sport Hydro hulls must resemble all Sport Hydro, Limited inboard, Unlimited Light and Unlimited Hydroplane classes of present or past design as closely as possible. Outrigger, Modified Outrigger, and or Tunnel hulls are not permitted. The width of the hull extending from the rear of the front sponsons to the transom must be a minimum of 8 inches in width, measured at either the deck or chine line, whichever is widest. All Hulls must be limited to a maximum overall length of 52 inches and a maximum overall width of 28 inches.
SUPER SPORT MONO
Spec engines will be a Zenoah G260 PUM ONLY. The Engine may run a stock unmodified 257 or the original 644 with choke carburetor. No internal modifications allowed. Recoil pull start must be the primary method of starting. EZ start and pulleys acceptable. Mono” is a hull that has a continuous wetted surface when operating at racing speed. Strakes shall be no more than 3/4 of an inch wide and 5/16 of an inch deep. The hull maximum length is 60 inches, bow to stern, and the maximum gross weight is 25 pounds, including fuel.
Any LSG-27 engine allowed. Pipes allowed. Exhaust must exit thru transom. No part of exhaust more than 1" aft transom. Engine hatch required. Motor will be completely covered. The hull length is maximum 51" and minimum 49". Minimum width at center of hull is 18". The max width of bottom at transom is 11". Strakes or riding pads are not legal. (no strakes, keels, or chines on bottom. That means the bottoms are flat in a scaled down size boat). Must have 2 scale drivers with a minimum height of 3.5" with life jackets and helmets. Boats will have “JS” followed by number on both sides of the hull. Minimum height 3.5”
Any stock or modified commercially available piston ported fuel induction 2-cyclegasoline engine not to exceed 1.83cid / 30.000cc. All engines must have a canister muffler, custom muffled exhaust system or tuned pipe. With the exception of the canister muffler the muffled exhaust system or tuned pipe must be enclosed by the hull. Minimum length is 42", maximum length is 49ʺ. Minimum width at the widest point is 15", The width must be in proportion to the length. The boat must be painted or finished in the spirit of a racing scale model. Two drivers of scale-like appearance with helmets and life jackets must be used in the driver/rider compartment.
SEE THE IMPBA SECTION “I” LARGE SCALE GAS RULES FOR MORE SPECIFIC INFORMATION Impba.net