What do you think about "e-soaring"?

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henryk

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blane.c

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-its a pity, I was wietness of this crash=left wing was destroyed at 50 m level,very smooth weather...

SKOWRONEK was take off at halve power (1/2 from 20 HP !)
=empty weight 120 kg,1.1 l VW motor (RC modell like !)

Jozef was made device for wooden propellers copying...

http://basia38.tripod.com/sitebuildercontent/sitebuilderpictures/antonow.jpg
=the compliment letter from O.Antonov .
It is a cool looking propeller, don't see many like it.

It is a cool thing a letter from O. Antonov. no doubt.
 

Bille Floyd

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Dear friends,

In my “New Member Introduction” thread I mentioned one idea – “E-soaring as possible new competition class”. And I really would like to know your opinion.
...

Just dreaming with my morning coffee dear friends…


But what you thing about this idea?

Best regards!
Martin
I think it's a Great idea !!

Safer --- i lost both legs below the knee in a Hang gliding tow accident ;
i ain't as Brave , as i use to be ... (Got to # 4 in the world, at ACRO on a HG)
when i was young and Dumb. Leaving enough in the tank, to get back from no
where , is a major + for me ; (and) my displeasure for walking with fake legs
in a hot Desert , if i screw-Up , (yea i've Done that).

Lines up with My schedule --- i quit the sailplane club, the day when cloud
base was 14K ASL, over Las Vegas, and there wasn't anyone to tow me up ;
yep , i went back to flying my rigid wing HG, (don't need no stinking Tow plane).

Light 103 compliant , decent performance composite gliders, with
an engine ; it's an absolutely, "Awesome" idea !!!!!

Anything over 30:1 glide , will do just fine. A 30:1, will be a LOT easier
to land in a tight spot, than a 40 or 45:1 will be ; for me , the extra performance
just isn't worth the higher risk.

Could someone build me a Kit, for one of those , please ??
I figure that if i build few for my friends , mine will be Free ; and
i know a 1/2 dozen guy's, i could probably talk them into that !!

Bille
 
Last edited:

John.Roo

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Wow - I am impressed of many new posts in such a short time :)

First - the props.
It is interesting how many different designs are existing.
In electric aviation are actually very popular eProps
https://www.e-props.fr/
And this is sample of very "slim" blades.

As I mentionned - we use Woodcomp Varia
http://www.woodcomp.cz/wp-content/uploads/2016/09/var-2-leaflet.pdf

But also DUC has interesting performance
http://www.duc-helices.com/index_page.php

And on Phoenix with Jabiru engine is customer vary happy with wooden 2 blade Sensenich
http://www.sensenich.com/product-category/propellers/aircraft/?filter_material=wood

However - the is only a very limited amount of types able to in flight adjusted and feathered (mechanically or electrically)...
Of course I understand that - it is very limited market for that special type of props.
 

blane.c

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Sounds from Garmin VIRB are a bit modified... You can speak in cockpit and you don´t need to wear headsets, however I confirm you can hear sounds different from ICE :)

Good point - manifold pressure is very usefull when used on IC engine and variable pitch prop. I suppose that with electric propulsion will be probably necessary measure also torque to estimate efficiency (using relation between torque, temperature, rpm, power...). Or maybe some different way, but actually I cannot tell you exactly "how" :)
I have to open this discussion when I meet electric motors and controllers producers.
As you fly along using the battery the voltage steadily goes down and so to maintain the same power the amperage steadily goes up? So that the watts stays the same? So if you move the propeller but maintain the airspeed in level flight the watts goes up or down in relation to the efficiency of the propeller? So by empirical method you could over time build a chart or graph and know how many watts it should take to hold a given indicated airspeed at a given density altitude (the propeller is more or less efficient with density altitude) and adjust the propeller accordingly? Or program it into your smart device? Indicated airspeed, altimeter set at 29.92hg, and the required wattage then adjust propeller to maintain speed?
 

John.Roo

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I think it's a Great idea !!

Safer --- i lost both legs below the knee in a Hang gliding tow accident ;
i ain't as Brave , as i use to be ... (Got to # 4 in the world, at ACRO on a HG)
when i was young and Dumb. Leaving enough in the tank, to get back from no
where , is a major + for me ; (and) my displeasure for walking with fake legs
in a hot Desert , if i screw-Up , (yea i've Done that).

Lines up with My schedule --- i quit the sailplane club, the day when cloud
base was 14K ASL, over Las Vegas, and there wasn't anyone to tow me up ;
yep , i went back to flying my rigid wing HG, (don't need no stinking Tow plane).

Light 103 compliant , decent performance composite gliders, with
an engine ; it's an absolutely, "Awesome" idea !!!!!

Anything over 30:1 glide , will do just fine. A 30:1, will be a LOT easier
to land in a tight spot, than a 40 or 45:1 will be ; for me , the extra performance
just isn't worth the higher risk.

Could someone build me a Kit, for one of those , please ??
I figure that if i build few for my friends , mine will be Free ; and
i know a 1/2 dozen guy's, i could probably talk them into that !!

Bille
Thank you for that post!
I remember that long time ago we did modification of UFM-11 Lambada to be operated by disabled pilot (rudder has been operated by hand). The pilot has been able to enter to airplane, dismantle his wheelchair (his design - very light construction), secure it to co-pilot seat and fly.

The only problem I can see is here "light 103 compliant..."
If I remember well this is special US catogory where
(1) Weighs less than 254 pounds empty weight, excluding floats and safety devices which are intended for deployment in a potentially catastrophic situation;
(2) Has a fuel capacity not exceeding 5 U.S. gallons;
(3) Is not capable of more than 55 knots calibrated airspeed at full power in level flight; and
(4) Has a power-off stall speed which does not exceed 24 knots calibrated airspeed.

I copied this info from here:
https://www.eaa.org/eaa/aviation-interests/ultralights/getting-started-in-ultralight-flying/about-faa-part-103-for-ultralights

I am affraid that 115 kg EW for electric composite airplane is very difficult goal. Especially with combination of 24 kts stall speed. "Glider like" desin will have also problem with 55 kts Vne, but this could be electronically controlled (theoretically).

Ideal category for basic electric TMG is LSA-Glider (or LSA-airplane).
Than is easy to use Rotax 912 (install weight arround 200 lb) or electric propulsion because MTOM is 1 320 lb. Less than MTOM 1 320 lp is problematic due to a battery weight.
In my opinion is minimim bat. capacity between 12 to 15 kWh (= weight of 130-150 lb) in case of two seater. This depends not only on requested endurance, but also on planned takeoff power.

Basically you are interested in one seater or two seater configuration?
Because Part 103 allows anyway only one seaters if I remember well.

Best regards!
Martin

P.S.
Tow plane doesn´thave to be "stinky" :)
 

John.Roo

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As you fly along using the battery the voltage steadily goes down and so to maintain the same power the amperage steadily goes up? So that the watts stays the same? So if you move the propeller but maintain the airspeed in level flight the watts goes up or down in relation to the efficiency of the propeller? So by empirical method you could over time build a chart or graph and know how many watts it should take to hold a given indicated airspeed at a given density altitude (the propeller is more or less efficient with density altitude) and adjust the propeller accordingly? Or program it into your smart device? Indicated airspeed, altimeter set at 29.92hg, and the required wattage then adjust propeller to maintain speed?
You are right - voltage is slowly going down so current goes up.
Because we use 400 V system is the difference relativelly small.
If I have less than 30% of battery and I go to land than I know, that in case of emmergency takeoff I will have lower available power. Therefore I am glad that on display I see also info about "requested power" and "available power"

Idea of empirical method of adjust. prop / efficiency measuring is good.
And will be easy to record data - actually we had available only small memory in controller, but now we will test something like "black box" accessible via cell phone.
Thanks for suggestions!
 

Bille Floyd

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Messages
166
...
Basically you are interested in one seater or two seater configuration?
Because Part 103 allows anyway only one seaters if I remember well.

Best regards!
Martin

...
Single seat , is all the FAA allows, for , "Powered" ultralight, 103 compliant.
There is a way to train a new pilot, tandem with an instructor however , by
removing the engine and teach in glider-mode only , (Towing) ; when
it appears the student can fly by himself, then just remove the tandem
instructor , and put the engine back on the plane.

Air Atos did a good job of building a single seat E-glider, that
has decent performance pictured below . The model was made from an
already existing , flying wing , so the swept wing is NOT
adding much to the performance ; make the wings without so much
sweep, and add a larger tail and rudder, and the performance numbers
should go UP.
https://www.homebuiltairplanes.com/forums/threads/air-atos-wing-3axis-from-a-trike-wing.30917/
 

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John.Roo

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ATOS Wing is interesting project.
I am in touch with Felix and I am really interested to try it :)

But I was thinking more about very light e-glider like Gekon (Axel) or Sagitta. Interesting are also modifications of French EXEL - EXELEC and SUNEXELEC https://www.sunexelec.com/sunexelec
This types are built from composites and this is technolory I know.
Would be nice to make small one seat electric glider suitable for Part 103, but in that case must be construction very simple and extremelly light.
By the way... is in case of Part 103 rule weight battery counted in Empry Weight? Or is like "fuel"?
 

blane.c

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I propose that you took a propeller blade in your hand (any prop..real one or just a small RC model) and check again your change from drive to windmilling regime.
You will see, that you cant have both, no mather how you turn the propeller blade....no matter the pitch rotation or direction of turns.

If propeller is "normal" made for the plane propulsion, then rotating the pitch blade angle for 90° it really could became a windmill blade and it will rotate the main shaft in oposite direction. But looking closely on the propeller blade local airfoil angle of attack it is a mess!! The pitch distribution along the prop blade is totally wrong. So, such propeller acting as a windmill will have very mad efficiency. Using such thing on a glider with intensions to "harvest" energy from glider while thermalling, you will braking the glider more, than "harvested" energy worth.

I will make a drawing to represent more graphically what I am talking about:

View attachment 30167

Try to draw vectors of two remained drawings for yourself... :)
Simple rotating of the blade wil not work. You must change also the twist (local change of blade airfoil AoA). Such propeller dont exist yet.
"Ivoprop" was somehow capable of small change of the twist by elastic blade structure and a torsion steel shaft from root to tke blade tip, but it was "ground" adjustable only, and change was really smal compared with what we are talking about to change from drive to windmill.
As we are talking about efficiency, any deviation from the ideal could be usseless.

Mitja
4 bladed prop. 2 blades for propulsion, 2 blades for charging. 2 blades fold forward, 2 blades fold aft or clutch the pairs independently of each other.

Otherwise it could be to use the hypothetical single blade is more efficient (one bladed propeller) idea except the blade on one half is for propulsion and on the other half for charging the one not being utilized would be in "zero" pitch. My complaint with single blade has always been "augering the bearings" but if bearings are stout enough to handle the off-center loading?

If charging using the propeller is important and looking for more efficiency charging with the propeller also there is the opposite solution, make the propeller most efficient as a charging propeller and secondary efficiency as propulsion.

Then of course there is always the Benjamin Franklin way. https://www.bing.com/search?q=benjamin franklin lighting and key&qs=n&form=QBRE&sp=-1&pq=benjamin franklin lighting and key&sc=3-34&sk=&cvid=2138433007AB443F87461E8DC3676ECD
BEN FRANKLIN AND KEY.png
 

John.Roo

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I am very interested to test idea of re-gen flight (doesn´t matter if during descent or in thermals). But this requests not only modified prop. but also upgrade of our controller...

I already mentionned Mr. Barnes - he work on technical background of re-gen flight a lot.
 

John.Roo

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By the way....
I found nice photo from our flying with electric Phoenix on int. airport Stockholm Bromma :)
Very windy day (90°crosswind) + a lot of trafic.

Big thanks to very friendly ATC and Bromma airport managers and workers!

IMG-20200211-WA0001.jpg
 

blane.c

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There is often a fair amount of static electricity generated in association with flight. Mostly it is dissipated with static wicks. If it could be harnessed instead?

Helicopters working whether logging or servicing high tension power lines, the first thing done is ground the helicopter because the electricity generated by the rotors will knock you on your but* otherwise.

Perhaps the "static" electricity generated by the propeller and/or the aircraft shouldn't be ignored or thrown away? Perhaps the propeller could be designed to "enhance" the build up of static electricity and to help charge the batteries? Of course one wouldn't want to build a lightning magnet … would one? Ah controlling chaos a never ending quest.
 

John.Roo

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Hello dear friends!
I am back from another trip to North.
This time was really challenging - we flown from Sveg (Sweden) to Roros (Norway).
It means international winter electric flight :)

It was amazing to land and takeoff from ice, snow and fly over snowy mountains - all with electric propulsion.

Today just few photos, later on also technical details....
20200218_084017.jpg
20200218_102805.jpg
20200218_113730.jpg
20200218_114343.jpg
 
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