Let me get this straight: is the new (higher powered) drive system now standard on all RK models?

From : Don Stackhouse

There are two different "new" power systems.

The MPS-1A replaces the old MPS-1 on all current production RK kits. It uses a single motor, and other than some small improvements in efficiency, the power is essentially the same. The improvements are mainly in the areas of structure, reliability, smoothness, and a wider variety of available prop sizes for folks at higher altitudes. It also has parts that are more readily available to us from a more reliable supplier, so we shouldn't be hit with long and unpredictable lead times that shut down production. This is also good for you, since it means we get to stay in business and continue to develop new "toys" for you to play with, and it also means that if you order something that we're out of and have to put on backorder, the delay shouldn't be nearly as long and unpredictable as what we were running into with our previous prop supplier.

The new MPS-2A is a twin motor system driving a larger prop. We have several new planes in development that use this system as standard equipment, the first of which will probably be our new Ryan ST. Some of the existing single motor airplanes such as the WW II warbirds also perform well with the MPS-2A, and we will be offering the MPS-2A as a stand-alone product for folks who want to upgrade, as well as for scratch-builders. We will also offer the MPS-2A as an upgrade option in place of the standard MPS-1A to new kit purchases for an additional $8 per motor system.

I don't anticipate upgrades to the twin motor airplanes, they already have plenty of power, although theoretically it's possible. Joe and I rarely use more than half throttle even for takeoff in an Electra, so one with a pair of MPS-2A's would be downright scary at full throttle, and would be lugging around some unnecessary extra weigh in cruise. OTOH, the lower current per motor might have some interesting effects on the motors' electrical efficiency, so it might be interesting to experiment. It's on our "to do" list.

Don Stackhouse
DJ Aerotech