Electric power is a subject I have been researching ever since I saw Mark Beierle's electric Thunder Gull at OSH many years ago. However my interest was in a self-launching glider. Re: Tristan's post excerpt below - I already have an ultra-efficient airframe, a kitbuilt Albastar Apis WR.

It's a 13.5 meter span glass glider with realistic, verifiable 38:1 glide performance due to its low weight.

Albastar is a composite mfr who does contract work for some of the well-known German glider mfrs, and after a time began to design their own aircraft. They sold the Apis intellectual property and name some time ago, and it ended up in the hands of Pipistrel - who have just got EASA cert on their Velis design etc as noted by Mike in his post below.


Pipistrel sold the Apis as a motorglider with a typical retractable 2-stroke engine on a mast. Originally it was available as a pure glider as well. According to Pipistrel's website the Apis is now out of production, which is news to me since the last time I looked at their site a few months ago.

Albastar is not out of the picture just yet. They have their own glider in production called the Albastar AS, available in 13.5 m and 15 m span.


The pics reveal the fuselage to be almost identical to the Apis with the addition of a retractable mainwheel. The interesting feature is the FES Front Engine Sustainer powerplant. This is a smallish outrunner electric motor similar in size, weight, and output to what would be a largish powerplant for giant-scale model aircraft. The motor is mounted in the nose and as seen in their pics, it turns a small-diameter prop with blades which fold back against the fuselage when not running. This system is available on a number of gliders sold in Europe at this time.


It's called a "sustainer" because when installed on a large, heavy or 2-place glider, it can be used to maintain altitude in no-lift conditions and save landing out. In a smaller, much lighter glider like the Apis, the system has enough thrust and duration to launch from a dead stop on the runway. An Apis would require far, far less thrust than a Zero powerplant can generate. And once I'm at altitude I turn it off and fly for a couple of hours with batteries running instruments and radio only. I'm content letting someone else's R&D serve my purposes since my application is almost exact as Albastar's AS so I contacted FES about installing a system on my Apis. On the following link they explain that they don't really sell kits or components to DIY the job, and I understand why. A bulkhead for the motor/prop needs to be installed and strength calcs for this and the battery trays and W&B need to be done in a way that takes them off the hook for the engineering aspect of the retrofit.


They replied they could install a FES in my glider if I shipped it to Slovenia so they could control all aspects of the installation. Cost would be around $16000 USD, not including shipping, and turnaround time would be 90 - 120 days or longer depending on their workload and schedule.

$16k is more than I have in the glider. By rough calc, $16k could pay for 4+ years of tows to 2000' AGL considering my flying habits.

FES - the business - is located in Slovenia, as is Albastar, as is Pipistrel. I believe they all test at Lesce Bled airfield, where the pic of the Apis hoisted by the three guys was taken. The area has an aerospace brain trust that is quite mobile much like Wichita in the 60s and 70s - familar faces repeatedly encountering familiar faces as they move around from employer to employer. People at Pipistrel with whom I have interacted have a pragmatic and enthusiastic approach which makes me think they are definitely on an upward trajectory. What I DO NOT get from them is the pressure one feels from many of the e-acolytes in the US that everybody running IC power MUST change their ways if they want to be hip, or want to avoid being sent to gulag.

My $.02 and YMMV...

Chris K

On 6/14/2020 12:19 PM, Tris Hotmail via KRnet wrote:
I have done all the groundwork for this exercise with a Rutan Quickie (Q1) and 
have the aircraft and the electric powertrain donor in my hangar.

On Jun 14, 2020, at 12:54 AM, Gary Sack via KRnet <krnet@list.krnet.org> wrote:

I will go one further and offer 81JM as a test bed to anyone who can put
together a credible plan to electrify her. She is currently flying with all
basic instruments working.

On Thu, Jun 11, 2020, 11:36 Mike Stirewalt via KRnet <krnet@list.krnet.org>

Someone in the initial thinking/designing phase of a KR project might
consider using electric power instead of our tried and true engines.
Pipestrel just got their trainer approved by EASA and the FAA can't be
far behind.

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