Ventus 2cxa with FES

John Galloway wrote, On 4/17/2014 11:20 AM:
IMHO it doesn't matter what kind of engine you have - at the
moment you reach for the start button of any motorised glider
you have to be 100% certain in your mind that it will not start
and have planned for that possibility. Then its nice when it does
start.

The actual probability of the engine not starting may vary
depending on the type and service status of the engine system
but the short term internal mental tool of 100% certainty of non-
starting should not.

(Even with the FES)

Perhaps the plan could be the same one you have for the wing spar
breaking, or a control rod disconnecting.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

On Fri, 18 Apr 2014 13:54:13 -0700, son_of_flubber wrote:

On Friday, April 18, 2014 4:44:42 PM UTC-4, son_of_flubber wrote:

Does the math/physics/dollars work for single-use (non-rechargeable)
battery pack for FES?

A quick look seems to indicate that the energy density of
non-rechargeable alkaline batteries (the flashlight kind) is somewhat
better than rechargeable LI batteries (the cellphone type), so a
single-use-FES is not on-the-face-infeasible.

Hint: there are AUVs working under the ice shelves in the Antarctic that
run off a pack of alkaline 6000 D-cells because these are the best
batteries to use atthose water temperatures.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Just for those interested, there is also the Selfstarting Binder EB29D with a Watercooled electric Motor . (no connection to Mfg) for details see
http://tinyurl.com/pndtp69

So having FES increases the number of days that one might attempt XC?
And consequently one will turn the FES on more often than once every five years?

Do any FES owners care to confess how frequently they turn on the motor?

son_of_flubber wrote, On 4/19/2014 11:26 AM:
So having FES increases the number of days that one might attempt XC?
And consequently one will turn the FES on more often than once every five years?

Do any FES owners care to confess how frequently they turn on the motor?

Confess? To what? Getting good value out of their purchase?

If a pilot isn't using the FES on 10% to 20% of the flights, the pilot
has wasted his money buying the FES. The FES can and should be used to
increase the amount and quality of soaring the pilot does, and flying so
conservatively it's rarely needed will not achieve that goal.

An FES (or any sustainer and self-launcher) sets you free to explore
soaring to it's fullest. What a sad thing if the pilot doesn't do so.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

Sof, it is a bit more complicated than that.

Just talking cross-country flights and only considering using FES to get home after having started (which is what I suspect you were getting at), I have only last year as a reasonable data set (illness andother things restricted my flying in 2011 and 2012 to few flights).

I did 17 cross-country flights in 2013and used the FES to get home on 3 or 4 of them. If 4, one was to be certain of crossing a big gap close to home and arriving with enough height to do a decent circuit/pattern, and avoid the risk of landing out in possible a bad field at the last moment.

But as well as those uses while completing flights, on 2 occasions I had winch launches, did not get a good thermal to climb away in time, and used the FES for a few minutes from about 700 feet to 1000 feet to avoid a relight - after which I climbed to a start height and returned to my start line (the home airfield) before doing an otherwise motorless flight. It is invaluable for such occasions too.

Then there were 5 other flights when it was barely soarable, certainly not good enough for cross country, but I used the motor locally - either just to keep in practice, or to do some flight tests to assess duration and climb rates (I have been doing some test flights as required by our airworthiness system and for feedback to Luka, the designer).

Dunno if this is what you wanted, but hope it helps.

Chris N