CubCrafter’s Ideal Fun Airplane
By Bruce Brandon
Among the many beautiful aircraft on display at the Sebring U.S. Sport Aviation Expo in Florida last month, one that stood out for me was the CubCrafters Carbon Cub. This aircraft is a monument to working within a system of FARs addressing LSA that are constantly changing and at times appear to be less than logical. As we are all aware, LSA has a maximum weight restriction of 1320 lbs. for a land airplane (why not 1500 lbs. or even 5000 lbs.?) set by ATSM.
The maximum empty weight of 902 lbs. for the Carbon Cub is currently derived from a somewhat convoluted regulatory formula. (This formula is reported to likely be changed in the near future in the ATSM but probably won’t have a great effect on most LSAs). To meet the LSA standard of 1320 lb. gross weight CubCrafters doesn’t stop with measuring just to ounces, is measures in grams (FYI an ounce consist of 28.3495 grams, but you already knew that). To keep the weight within the 902 lb. maximum empty weight limit for SLSA, the aircraft has small main tires and tail wheel and other weight saving tricks when it rolls off the assembly line. If, for some reason the aircraft should weigh more than 902 lbs., a seat will be taken out to meet the limit and is certified as a single seat SLSA. The engine is limited on maximum continuous power of 80 hp to comply with the SLSA restrictions on maximum empty weight even though it is rated for 180 hp for takeoff. Fuel capacity is two 12 ½ gallon
tanks with 12 gallons usable in each.
CubCrafters has made improvements for the 2013 model. It has installed a new lighter starter, redesigned the cowl for better engine cooling, an improved electrical monitoring system and modified the cowl. The cowl modification gives better engine cooling and, perhaps most importantly, greatly improves cabin heating.
With this focus on weight, one gets an outstanding tail dragger that almost literally jumps off the ground thanks to its 180 hp CubCrafter’s CC340 engine. The experimental Carbon Cub EX (see below) has taken off in as little as 19 feet in Alaska (don’t try this at home) and can climb like a scalded dog (approximately 2,100 feet per minute). The CC340 is lighter than a certified engine, in part, because it has electronic ignition, aluminum oil sumps and uses an 80 inch diameter propeller with a 50 inch pitch made 80% wood and 20% carbon. It has an impressive 2400 hour TBO.
For those who want this airplane with more options that would drive the empty weight up past 902 lbs, the aircraft may be recertified as an ELSA. CubCrafters can perform this at the factory. It returns the SLSA certificate and applies for an ELSA certificate and the aircraft maximum empty weight of 902 lbs. is removed (the 1320 lb. maximum gross weight still applies). This allows many bells and whistles (e.g. tundra tires, large tail wheel more avionics, etc.) to be installed and frees the owner to modify the aircraft without first having to get the OEM’s approval and to perform maintenance and inspections if he/she has completed the LSA sixteen hour maintenance training requirement. Private pilots can also fly the ESLA version at night.One must keep in mind, however, that once the aircraft becomes an ELSA it is possible but difficult to return to the SLSA category under the current regulatory scheme (go figure!).
A third option is to purchase the Carbon Cub EX, the kit version. This is the almost identical airplane (the empennage is slightly modified because of the variety of engines the owner may put on the aircraft). Since it is experimental, the owner builds it and determines the gross weight. The airframe (either factory-built or kit) has been designed and tested to 1865 lbs. Because of the simple construction and weight saving materials, the payload approaches 1,000 lbs. If the owner elects to certify the airplane above 1320 lbs. it does not qualify as a LSA thus requiring a medical and private pilot certificate to fly.
As with any airplane, the incredible short field performance comes at the price of compromising cruise speed which is in the 100-110 mph category. But then again, having the short takeoff/landing performance combined with the load capacity (of the EX) is the real reason for buying this extraordinary airplane. I soloed in a J-3 Cub in 1966 and wish CubCrafters had been around then.
(Images provided by CubCrafters)