Using a motorcycle engine for a homemade plane may not be ideal for several reasons:
Power-to-Weight Ratio: Aircraft engines are specifically designed to provide adequate power while being lightweight. They need to generate enough thrust to propel the aircraft into the air. Motorcycle engines, on the other hand, are typically designed to provide power for two-wheeled vehicles and may not have the optimal power-to-weight ratio required for aircraft use. They may not generate enough thrust or may be too heavy for efficient flight.
Cooling and Lubrication: Aircraft engines operate under different conditions compared to motorcycle engines. Aircraft engines need effective cooling and lubrication systems to withstand the higher RPMs and continuous operation during flight. Motorcycle engines may not have the necessary cooling and lubrication systems designed for sustained operation in an aircraft.
Fuel Efficiency: Aircraft engines are engineered to be fuel-efficient to enable longer flight durations. Motorcycle engines are optimized for different considerations, such as power output and acceleration, which may not prioritize fuel efficiency to the same extent.
Redundancy and Safety: Aircraft engines often employ redundancy features for safety. They may have multiple spark plugs, magnetos, or even multiple engines for twin-engine aircraft. These redundancies help ensure the engine's reliability and mitigate the risk of engine failure. Motorcycle engines may not have these built-in redundancies, which can be critical for aviation safety.
Certification and Legal Considerations: Depending on your location, there may be legal and certification requirements for aircraft engines. Authorities often have specific regulations and standards for aircraft engines to ensure airworthiness and safety. Motorcycle engines may not meet these specific requirements, making it difficult to obtain the necessary approvals for your homemade plane.
If you are considering building a homemade plane, it's essential to consult with experts in the field of aviation and adhere to applicable regulations and safety standards. They can provide guidance on suitable engine options and help ensure the safety and viability of your project.