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Here is another short article on motorgliders and the differences between the three types. This article is not intended to be a training manual or syllabus. We will provide some basic information concerning the motorglider. The term “motorglider” is very broad in its application. I hope this provides a little more insight into this subject area.

According to the FAA FAR 1.1, a motorglider is not defined. There is a glider. There are three basic categories of motorgliders:

  • High-Performance Self-launch (HPSL)
  • Sustainer
  • Touring Motorglider (TMG)

Let’s review each of these.

High-Performance Self-launch

These gliders (or sailplanes used interchangeably) are usually powered by 60-75 Horsepower 2 cycle engines.  Some are pure electric. Some examples of these gliders are the Schempp Hirth Arcus M, HPH Twin Shark, or the Antares. Most gliders are manufactured in Europe and offer either HPSL or Sustainers in their models. These HPSL gliders may be designed for one person or two. The aircraft has unique performance capabilities. The Glider Flight Manual (GFM) should be referenced in terms of takeoff distance and operational characteristics. Proper training is essential to ensure safe operation and operating procedures. The HPSL does require additional FAA training and a logbook endorsement to act as a pilot-in-command. This is found under FAR 61.31 (J) (iii). Under current FAA Rule, the FAA does not require USA pilots to have a motorglider endorsement attached to the pilot’s certificate; however, EASA does, as do other countries.

The FAA rule mentions a relief from training as long as the pilot logs motorglider time before August 4, 1997. 


Photo by Petr Kolmann of an HpH Twin Shark
High-Performance Self-Launch

Sustainers

What is a sustainer glider? These can be the exact same in appearance as the HPSL at first glance but without self-launch capabilities. The engine used is usually a 2-stroke, but its horsepower outage is usually reduced by 50%; horsepower is around 35. The lift-to-drag ratio does not provide adequate performance for using a sustainer to self-launch (take off). That being said, many have tried! The engine operation is similar, if not identical, to the HPSL. These sustainer-type gliders have evolved considerably over the past decade; some even have small turbine engines.


Photo by Petr Kolmann of a HpH 304 ES
Front Engine Sustainer (FES)

Photo by Sean Franke of a HpH 304 SJ
Jet Sustainer Engine

Touring Motorglider

The TMG may or may not have the appearance of a glider in design, but the TMG may have a similar appearance to that of a powered single-engine airplane with long wings and sleek fuselage construction. Please refer to the FAA GFM and Airworthy Certificate that must be displayed to the pilot in the cockpit area to determine if you are flying an airplane or a glider. Remember you must possess the current pilot certificate to operate either. As you see below, the TMG is more like an airplane in its appearance. Its self-launch characteristics are far simpler (usually) than those of an HPSL. The only exception is the Stemme, where the operation of its systems is very advanced.

Stemme S12
Photo by Simon Rainer

The next part of this series will continue in two weeks, with the unique endorsements required to fly motor gliders and insights into training.

Banner Photo by Petr Kolmann