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Aug 15, 2013, 10:38 PM
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goduranus's Avatar
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Build Log

EDF Flying Saucer


Alright, I'm gonna put this here instead of the multicopter forums because this thing I'm dreaming up has a "Scale" feel to it. But hey, it uses EDFs too, and has all the pros and cons that come with them.

So bascially, I was building a foamie EDF saucer, but it's pretty hard to get good alignment with foam. So I'm going to experiment with 3D printing.

This is the result:



It will be 60cm(25"?) across, made out of 6 identical sections, joined together with 3mm nylon standoffs, each section has a 70mm 2300KV EDF with 60A Brushless ESC, and a strip of LED tape beneath the EDF to give it that Ufo glow. A center section will house the batteries, the flight controller, and the top center dome will house the GPS.

Top view showing the sections:


Bottom view showing the LED glow:


A illustration of it fully-assembled with red LEDs:


It will weight 5120 grams:

Hull plastic, 1060 grams
6 X 70mm EDF(3X reverse), 1020 grams
6 X Hobbywing 60A ESC, 400 grams
6 X LED Strips, 240 grams
2 X 6 S 6000mAh batteries, 1900 grams
3x Retracting Landing Gear, 150 grams
DJI WKM, 150 grams
Glue, wires, nuts and bolts, 200 grams

And with each EDF giving 1500 grams of thrust at full battery, and about 1200 grams at 3.6V per cell , it will have a total thrust of 7000-9000 grams.

Air time is about 6 minutes in hover, 3 minutes when maneuvering.

My major concern is that to save weight, the hull will be only one milimeter thick, not sure how much problem that would led to during print.
Last edited by goduranus; May 22, 2014 at 04:40 AM.
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Aug 16, 2013, 01:02 AM
You know nothing....
Stuart A's Avatar
Could you use cnc cut XPS foam?Glassed and reinforced it would be stronger and I'm guessing lighter?
Aug 16, 2013, 01:15 AM
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goduranus's Avatar
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Foam would definitely be better, but I can't get CNC cut for foam around here.
Where do I get it?
Aug 16, 2013, 02:19 AM
You know nothing....
Stuart A's Avatar
http://wecutfoam.com/ in the USA
http://translate.google.co.uk/transl...fari%26hl%3Den they do quite a bit on the forums.
Have a look at D-FAST on here,Also clausxpf,may inspire you!
Aug 19, 2013, 04:39 AM
You know nothing....
Stuart A's Avatar
https://static.rcgroups.net/forums/a...20P8113429.jpg

From s/b foamies.
Aug 20, 2013, 11:06 AM
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Would a quadcopter housed in the flying saucer work as well??

Steve
Aug 20, 2013, 12:49 PM
You know nothing....
Stuart A's Avatar
Quote:
Originally Posted by SCALECRAFT View Post
Would a quadcopter housed in the flying saucer work as well??

Steve
Creative thinking!
Sep 09, 2013, 09:34 PM
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goduranus's Avatar
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Quote:
Originally Posted by SCALECRAFT View Post
Would a quadcopter housed in the flying saucer work as well??

Steve
https://www.rcgroups.com/forums/show....php?t=1956566

I went for EDFs because they require smaller holes in the hull, and sound a bit more similar to pop-culture UFOs,

I went with Hex because I was restricted by the size of the EDF, only 70mm ones come in reverse, so I had to get as many fans as possible to reduce the load on each fan. Could only get up to six though, as the WKM only has 8 signal outputs, and I need two of those for a turret I intend to add later on.

Anyhow, I worked on the foam saucer some more, pics here:

Assembled


Electronics Deck


Retracting Landing Gear


Throttle-linked Eerie Engine Glow
Last edited by goduranus; Sep 10, 2013 at 02:03 PM.
Sep 10, 2013, 01:44 AM
Team Mulikow
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Sep 10, 2013, 03:26 AM
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stegla's Avatar
How about a ply or lightply frame, with a foam saucer to give some shape and the ducts.

You will need a nicely radiussed intake lips. The initial cad drawing looks good but the foam model shows the fans sticking out proud losing that nice shape.

Steve
Sep 16, 2013, 12:46 AM
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goduranus's Avatar
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I've never worked with plywood before. Just off the top of my head, I think there's a tradeoff of performance and crash vulnerability/repair difficulty between plywood/foam/and printed hulls.

A hull built with plywood frames and some kind of sheet covering will probably be the lightest(~350 grams?), thus offer the best performance, but will require a complete reconstruction after any kind of hard landing.

Foam hull will be a bit heavier(520 grams), and a bit uglier, and a bit tougher. Even if totally destroyed, foam hull can be rebuilt in a week or two.

3D Printed Hull will be heavy(1 Kg), but building it will be a simple matter of drawing CADs and leaving the printer on overnight. Spare parts can be made endlessly. I should be able to carry 3-4 extra pieces, and repair most damage at the field in 10-20 minutes, allowing me to fly it very aggressively.

In any case, while I'm waiting for the printer(gMax on Kickstarter), I did some more work on the foam saucer. Now the landing gear signal wire is passed inside the hull, and the lights simulating "engine glow" are installed in their proper place:
Sep 17, 2013, 08:50 PM
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The past couple of days I've been fitting the electronics bay and calibrating ESCs, also doing some dynamic balancing of the EDFs using the cellphone accelerometer method.

Balancing the fans was pretty boring, so in between fan and fan, I turned some 1:144 Takara tanks into fridge magnets
Last edited by goduranus; Sep 22, 2013 at 09:43 PM.
Sep 21, 2013, 11:39 PM
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Alright, I wired up the engine lights and all the electronics. Only things left to do are the EDFs, then I'll do a ground effect hovering test.

Here showing off the engine glows and the landing gear retracts.

IMG 2790 (0 min 30 sec)
Sep 22, 2013, 09:05 AM
Lee Liddle
Knife Liddle's Avatar
Looks cool. That`s an intresting use of the retracts to kind of rotate the LG into place so that they can have the angle when lowered. Suggestion.......if the legs had a curve at the bottom, it would allow them to slide more easily in case you touch down with any lateral movement. Also it would give them (the wire gear legs) more of an ability to act as shock absorbers to soften landings.

You have the LEDs to get brighter when the fans have more power (this is the normal way to do it). It seems to me that a bad result of that will be that the LEDs will get brighter on the opposite side of the saucer than the direction that it will be moving. That may be the only way to set it up. I was thinking that if you reverse that relationship, then the saucer would get brighter in the direction that it will be headed. The neg to that would be that they would be bright while sitting on the ground and would dim as you power up.

If you put the LEDs on a separate channel, then you could mix them with a direct response to the throttle channel, then mix them to work opposite to the control input from the right hand stick, so that they would dim on the fans that are increasing in power and get brighter on the fans that are being reduced in power.

I hope that made sense. LOL Cool project, Good luck.
Sep 22, 2013, 09:10 AM
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D_FAST's Avatar
Quote:
Originally Posted by Knife Liddle View Post
Looks cool. That`s an intresting use of the retracts to kind of rotate the LG into place so that they can have the angle when lowered. Suggestion.......if the legs had a curve at the bottom, it would allow them to slide more easily in case you touch down with any lateral movement. Also it would give them (the wire gear legs) more of an ability to act as shock absorbers to soften landings.

I hope that made sense. LOL Cool project, Good luck.
i 100% agree.
imagine one of those legs getting stuck in the ground before the other two. your ufo is now a turtle on its back.

great work.cool project.


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