[warbird_fanatic]

Hi Guys,

I'm in the process of building a large scale Concorde but have never had the opportunity to use several ESC's in a plane before, My question is, I will be using 4 x 70mm edf's to get the bird off the ground, Do I provide 1 ESC per EDF and how do I go about connecting them all together, do I literally do a 4 - 2 - 1 connection for the 3 pin receiver connector and have a separate lipo per fan? Sorry if it sounds like a newbie post but the only Twin that I fly is my P61 which has 2 OS FS 60's in there!!! I've always flown with IC and single EDF 

[tsr]

Normal practice is one esc per motor. Some have been successful with multiple motors per Esc but they usually have problems at some point see Pontious' threads on RC groups for Valiant Victor and Vulcan, I think they are now all running multiple escs having started with one esc running four motors. Then it depends on what the output of your receiver is like. A lot find they have to have two outputs to drive four escs. Then it depends on the Esc if they have a bec or sbec then you will probably need only one of the rx connectors to have its power lead active. If they do not have the bec or sbec then you need a power supply for the rx.
Single power pack distributed to four motors or  four power packs one per motor. Debate begins,
Single pack Pros: Power availability even throughout run, power failure causes all four to cut so no sudden assymetric power. Maybe better for achieving CG see also less wiring below, only need one hatch and cooling solution may need to be a complex solution.
Pack for each motor Pros: One can fail and recovery under three is possible with careful throttle management, possible lower cost, less wiring depending on CG placement requirements, possibly easier cooling,

I have a couple of twin edf's boith using twin escs and single pack driving both motors.

That's all I know hopefully someone else will be along to fill in any bits that I missed

[PDR]

You really need one controller per motor with brushless motors - sometimes you can get motors to share a controller, but it's hit-and-miss. You can have either one battery pack, or two, or four - all these options will work, but you need to be careful to keep the battery-to-ESC cable lengths within the specified limits (usually 8"/200mm, but it varies between controllers).

You'll probably be wanting to use opto-controllers rather than BECs on a beast of this size, and in principle you can just connect the controller leads into a tree of Y-leads to a single Rx socket, but this depends on the Rx. Many people have reported problems where some types of Rx struggle to drive multiple ESCs, in which case you'll need some sort of current-booster "buffer" device in there to help. Alternatively (if your Tx has the facility) you can use mixers or "electronic Y-lead" functions to drive the ESCs from seperate receiver channels.

PDR

[warbird_fanatic]

Cheers Guys,
I was thinking along the lines of PDR's advice, I was also thinking about running each ESC on a different channel then mix them on the controller (Turnigy 9X) The controller and receivers have never given me hassle even with FPV (managed to fly 16k using a 2W amplifier in scotland last year)
At least then I have 9 channels to mess with, especially the nose as it wouldn't be a true concorde without plus I'm doing it as a memento for my grandad who was one of the designers and consultants for the Olympus engine :-)

[warbird_fanatic]

Right, everything's ordered! Bought 9 x 10kg high torque servo's, 4 x 70 mm 1.2kg output fans with motors, 4 x 80A ESC's (higher A just incase) and 8 x 5000mah 4S Lipo's which came to £370 - I told the wife it was all £25, what a bargain LOL!
Also ordered in some 30gsm tissue grp to lay up over the fuse with some high visc epoxy (had to order a 6kg container)
The wife's not too happy that the foam blocks are all lined up and being glued in the lounge :-D

[leckyBB]

Looks like you are heading in the right direction. One suggestion that might be worth considering, how about mixing the left and right banks so you could apply assymetrical thrust trimming. It might prove useful on such a large bird.

[warbird_fanatic]

Lecky, I was actually considering it as the concorde is quite a unique flyer from what I've been told from previous pilots, My grandad's warned about the landings being a bit speedy and also the stall speed being quite random but we'll get there, I was even contemplating making some vectoring shrouds for the ducts to give a bit more Elev trim! I've put every component on the scale inc the GRP products etc and the AUW is 3.97 KG with the 4 fans kicking out 1.25KG thrust each, it'll be more than 1:1 luckily, I didn't want to try flying it with a thrust ratio being less than the AUW just incase the thing needed a long run to get off the ground :-) I'm also doing 'proper' landing gear, twin nose wheel with 4 x 4 on the rears to give the full scale appearance, I started chopping up the polystyrene this afternoon into 3 fuse blocks which will have Ply shims so that it can be taken apart to fit in the car, it was either that or put it on the roof rack, Imagine the looks we would get!!!

[rogerandout]

Yes you are correct my first Thorpe Phantom was one piece and had to travel on a roof rack on Mk4 Cortina saloon, interesting looks as I drove up the A1

[warbird_fanatic]

That would have been hilarious!! I'm now trying to work out the scale of the thing, I've drawn up the fuse onto the blocks and the length is actually bang on 8 foot! Not sure what scale it would be, will have to find a scale calculator!
I lost my Nichrome wire somewhere so had to order some more so I can start carving the shape out of the blocks!
I bought some polystyrene insulation panels from Wickes yesterday @£3.99 each (1200x600x60mm) so I can carve the wing pattern out, I want it to be precise to aid the lift as a lot of models I've seen just have a flat surface which doesn't look too scale, Next thing will be finding a tarmac runway as I usually take off at the parents, they have 15,000 acres of farmland, might ask If I can get the tractor out and make a dedicated runway!!

[The Codfather]

This is sounding like a truly epic build! ...watching on, aka subscribed!

[warbird_fanatic]

Epoxy arrived this morning along with the 30gsm tissue, depending on how I can assemble the whole bird, I might make a mould out of it and build a few EDF kits, I'd love to build a turbine version but the scale would need to be increased to the point where the Fuse length measures about 16 foot!
I'm wondering whether to use Air retracts or use the digital servoless which I've used in all my other planes, HK do some alu versions which take weights upto 10kg!

[quorneng]

Look forward to seeing some picture of the build.

Now if you really wanted the right 'look'......

Just look at that wing section, all twists and curves!

[warbird_fanatic]

:-D

I'm stuck on the decals at the moment, I think I may go with BA livery, I've got a few A3 sheets of the printable decal vinyl (transparent) which will go great against the diamond white base coat once she's painted
Air retracts will need to be modified to accommodate 4 wheels instead of 2 but that shouldn't be a problem, I'll build a swivel arm with an extra spring for landing support.
Next up will be the lighting, I've sorted out the landing lights, not sure whether to buy strobes or LED's for the blinkers :-)
I just really hope the bird gets off the ground, The wing is going to be an exact copy of the real McCoy to encourage lift, I've seen too many Concorde knock offs with teething problems in the air because they've used a flat wing design!