Sacha
Active Member
I am interested in the SD-1 Minisport, it is a small light 1 seat plane in many ways very similar to the PIC-26. The prototype flies with a Trabant 2 stroke engine (2 cilinder 630 cc) in a direct drive configuration. Something of which I thought it could not be done, but I found in this Forum that Mark Stull tried it as well with a Mz 201 I believe.
The ploblem with 2 stroke engines is torque at the lower Rpm range where a 4 stroke performs a lot better. This is why we use reduction gears, but they add complexity and weight.
Here comes my question.... Is it possible in theory to build a 2 stroke engine with a LONGER stroke than square. The cilinder pushes a longer crank and travels a longer distance reducing the max Rpm but also optimizing the max torque in the 3000 Rpm range. This way we would not need the reduction gears and save money and weight.
There are probably many reasons why this cant be done with some significant drawbacks, so it would be nice to read what those are.
The sound of a 2 stroke in direct drive at 3000 Rpm is a lot better than one running at 6000 with reduction drive! Look at Youtube "SD-1 minisport" .
Sacha Knoop
The ploblem with 2 stroke engines is torque at the lower Rpm range where a 4 stroke performs a lot better. This is why we use reduction gears, but they add complexity and weight.
Here comes my question.... Is it possible in theory to build a 2 stroke engine with a LONGER stroke than square. The cilinder pushes a longer crank and travels a longer distance reducing the max Rpm but also optimizing the max torque in the 3000 Rpm range. This way we would not need the reduction gears and save money and weight.
There are probably many reasons why this cant be done with some significant drawbacks, so it would be nice to read what those are.
The sound of a 2 stroke in direct drive at 3000 Rpm is a lot better than one running at 6000 with reduction drive! Look at Youtube "SD-1 minisport" .
Sacha Knoop
