Earthstar Forums

I finally got airborne on September 6 for 19 minutes. My second flight was 33 minutes and got to explore the flight envelope a bit. Needed to throttle back on the 52 kW to avoid zooming past the 120 mph redline.

On my third flight, the belt broke at 300 agl. I had excess speed and sufficient luck to make it back to the field ok.


Examined the belt suitability for our application. Attached is my report. Feel free to comment or disagree. The bottom line is, allowing for powertrain losses, operating above 38 kW battery power is outside the best rated capability of the belt. I do not recommend doing so for long life of belt, plane or pilot.


Adjusted custom mode of Zero powertrain and re-pitched prop accordingly and flew a fourth flight. Will do more.


My mgl Xtreme efis records 'black box' data every second. For my new 30 kW battery power limit, climb rate was 860 fpm, based on height gained over one minute, at a somewhat arbitrary 62 mph asi. That'll do.


E-props claims their propellers are very efficient. That is what I am using. I plan to collect test data to get hard data on flight characteristics such as speed vs power, climb vs speed, and glide data (polar). Expect to do a maximum range test soon. Although I will report highlights here, the full data will be on the Facebook s Electric Aircraft Owners Group. That seems to be a better place to keep and share lots of data... and to find it later.

Hi Ray
Did you receive the replacement belt that I sent to you no charge?
In replacement for the belt that you damaged when you didn't align your drive properly.
It is the proper belt that is 14 mm wide
Rather than the aftermarket 12 mm belts that you were flying with that you had bought locally.
Don’t use belts that don’t come from me! Please. I am glad that you are a good pilot.
Happy Flying,
Mark

Sent from our iPhone

Thanks for the belt.

Have not picked it up in Maine yet. I will make that 3 hour round trip within a few days.

For clarification purposes, the 14 mm belt would have failed too. Its 17% greater rated strength
could have changed exactly where it failed, but it would have failed similarly.

I am glad I got the opportunity to become a better pilot.

--ray

Hi Ray
Do not fly till you have installed and aligned the belt I sent you!


Happy Flying,
Mark

Sent from our iPhone

Hello Ray,

some review comments, as a learner. attached an image of comments, just in case.

(curious, is “St.” in your surname also pronounced as “Saan” with a soft nasal n like Yves Saint Laurent? Same heritage, web searches seem to obscure this Saint’s heritage due to Yves, which must be much older.)

Rahul

Hello Ray,

some review comments, as a learner. attached an image of comments, just in case.

(curious, is “St.” in your surname also pronounced as “Saan” with a soft nasal n like Yves Saint Laurent? Same heritage, web searches seem to obscure this Saint’s heritage due to Yves, which must be much older.)

Rahul

Hi Rahul,

Have not been able to see your comments. Only see an empty file. Not sure why but I frequently have difficulties with yahoo. Tried 3 browsers without success.


As for my name, yes St is an abbreviation of Saint and is the same name as for Yves. My last name is the French version of "St. Lawrence". In my case it is comes from the native French town of my ancestor when he moved to Canada. Equivalent to being called "Tex" if you are from Texas. Way off topic but there it is.

Thank you Ray. it’s alright, they were minor comments anyways.

(so a persian got the roman who tortured St. Lawrence. tex is pronounced tech, btw)

For what it's worth, I just took my cowl and wing off and examined my
(Earthstar provided) belt: no signs of wear or fraying, and still tight
after two seasons. I have the 50kW motor, and have seen up to 75 kW during
STOL take-offs. I do not do these kind of take-offs often, usually stay at
30kW for the first 2 minutes, but it is good to know I have that reserve
for last-second go-arounds. That is also the reason I use custom mode with
full power and acceleration allowed. I figure, I'd rather have manual
control over how much torque I request. I would be interested in a
discussion on Mode, though. Does ECO mode really save charge if I rarely go
past 15 kW and don't accelerate hard? I use full regen, mainly to function
as speed brake. Anyone knowledgeable with an opinion on Mode settings,
please start a thread on that.
Martin & the Quark