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Albion 5m Electric soarer

All non-scale topis should go in here for discussion.
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Albion 5m Electric soarer

Post by Peter Balcombe »

With covering now complete and flight battery available, I’ve just done another quick assembly to check balance & impact on overall weight.
Even with a 5000mAH 5S LiPo (which just fits alongside the 60A ESC) I’m going to have to add roughly 570g immediately behind the motor to achieve rough fingertip balance at 93mm behind the root LE.
This should be a conservative starting point (33% root chord) given that the tip panels have a rearwards curving LE which should move the MAC aft a bit.

With that amount of ballast & the flight battery, the overall weight comes out at 5.2Kg (11.5lbs).
If we can get the expected 800W or so out of the motor, then the climb should be adequate.

Unfortunately, I forgot to take a photo of the assembled model, but previous pics of the bare model & covered tailplane should give you the idea.
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Albion 5m Electric soarer

Post by Peter Balcombe »

After fixing the previously identified nose weight into position using Silicone sealant (as 2 blocks located on each side of the fuselage, just behind the motor, leaving sufficient room to attach the motor connectors) I have just re-assembled to check balance & take a final pre-flight photo.

The 60A YEP ESC fits on the floor just behind the motor & slides underneath the weights. The 5S flight battery fits in the forward canopy opening behind the ESC with room for the XT90 connector down the side. A separate BEC will be used & will fit between the ESC & battery.
The Rx fits behind the battery.

The undersides of the tailplane, control surfaces & tip panel ends are red/white check.
Cliff will probably add some trim stripes to the basic covering at some point.
The weight & CoG are displayed on my DIY CoG meter.
Attachments
29423DFE-18FF-404A-BF45-B0EAE526CF19.jpeg
97A29589-6D7F-4561-9037-8E030ECA5021.jpeg
D1695283-582C-4034-8F56-2EA7EA700588.jpeg
B Sharp

Re: Albion 5m Electric soarer

Post by B Sharp »

That looks quite the business sitting there Peter. Well done and good luck with the maidens.
Brian :)
SP250

Re: Albion 5m Electric soarer

Post by SP250 »

Well done Peter - looks really good and pretty light for a 5m glider.
You've motivated me to get mine refurbished, just need to work out how to chop the 2.5m wing halves into two and add joiners / strength for a more easily managed and transportable 4 piece wing. Noting your dead weight for CG balance as well, I think a refit of the servo positions and GPS gear to move it all forwards will help too.

John M
Barry_Cole

Re: Albion 5m Electric soarer

Post by Barry_Cole »

Peter,
Any chance of details of the weight and balance device??

BC
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Albion 5m Electric soarer

Post by Peter Balcombe »

Barry,
A quick overview below, but if there is interest then I can provide detailed schematic & firmware in a dedicated thread in a more appropriate section.
Essentially the device measures the weight sensed at two points on the wing chord using standard beam load cells.
With a little bit of maths, these two weights & their locations behind the wing LE can be used to calculate both overall weight & location of the mean weight location between the two measurement points/location wrt the wing LE reference.

The load cells each contain 2 strain gauges whose resistance changes dependent upon deflection of the metal bar they are mounted on. The strain gauges are connected as a Wheatstonebridge (think full wave rectifier with resistors instead of diodes) & the small voltage changes as a result of weight applied to deflect the beams are amplified & converted to a digital value in small off the shelf HX711 modules.
A small Arduino processor module then calculates the display values and drives a serial data 16x2 LCD display

I think that I use 10Kg load cells, but will need to check that out.
The setup is easily adaptable to different uses by using different capacity load cells.
My mechanical arrangement is just one way of doing it, but never got around to tidying up the lash up.
My processor board has a voltage regulator, so I can operate from a 2 cell LiPo or equivalent.
Attachments
Overall unit
Overall unit
Two HX711 modules & Arduino Pro Mini
Two HX711 modules & Arduino Pro Mini
Barry_Cole

Re: Albion 5m Electric soarer

Post by Barry_Cole »

Peter, Thanks for that. More detail would be good, when you have time.

:) :) :) :)

BC
simon_t
Posts: 89
Joined: 17 Mar 2015, 21:45
Location: Herne Bay, Kent

Re: Albion 5m Electric soarer

Post by simon_t »

Great work with the Albion & CG/Scales Peter.

For others, if you want don’t want to build a CG/Scale, there is this (max 4Kg) (and others available on-line, capable of higher weights): https://www.hyperflight.co.uk/products. ... ring-scale (I have no connection with Hyperflight)

Simon
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Albion 5m Electric soarer

Post by Peter Balcombe »

Simon,
That maybe where I started from, or one like it.

I have found my design file, so will make up a connection diagram & start a new thread in the Equipment section some time over the next few days.
A note here is that in order to build this sort of unit, you need to be able to program the firmware into the Arduino board (needs the Arduino IDE installed on a PC and a USB cable) Unfortunately, it’s not just a matter of getting a pre-programmed Arduino device as the individual load cells need to be calibrated (by running an initial calibration program in the hardware) & the appropriate values inserted into the program before this is uploaded to the Arduino board. It’s not difficult, but a necessary step.
However, you can make a unit capable of handling larger weights if required - simply by using higher rated load cells.

As a taster, here is a link to a uTube video describing a strain gauge based set of weighing scales:
https://youtu.be/sxzoAGf1kOo
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Albion 5m Electric soarer

Post by Peter Balcombe »

The HK canned Outrunner motor & lack of cooling air exhaust proved too much for the ESC on a very hot day earlier in the year & the ESC gave up the ghost, causing Cliff to land quickly with a smoke trail!
Luckily, the battery is ok & the forward fuselage escaped with only minor charring!!
The motor may be ok, but have not risked putting power on it yet.

So …. a re-motoring job was taken on, together with making provision for air exhaust via the forward canopy.
It was decided to use an Airtek 4250/600 outrunner & equip this with a long shaft to enable it to be mounted further back due to its larger diameter. The long shaft is supported by a front bearing mounted in the nose former.
Cliff printed a couple of carbon loaded filament formers & the scheme allows the motor to be inserted/removed.
The pics below show story.

Motor mounts
Motor mounts
Extended motor shaft
Extended motor shaft
Motor in place
Motor in place
Front bearing & shaft
Front bearing & shaft

As there is now a 40mm+ gap in front of the motor, a nose ballast cylinder can be fixed up front. This has been cast in a simple plaster mould (made using a very lightweight 3D printed plug) & the result is shown below, together with a T shaped jig which allows the ballast cylinder to be held in position against the front former whilst being fixed using polyester resin, applied from the rear.

Nose ballast
Nose ballast

The nose ballast weighs 200g & equates to nearly half that previously needed behind the original motor. Hopefully, this should now be most of what is needed to balance the model.
The plan is to cut a NACA profile outlet in the front canopy.
Cooling air is taken in via an Aeronaut cool nose spinner.
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