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Old Yesterday, 04:45 PM
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Motor Amps.... well, you have to have a 'circuit'. So the Current TOTAL has to come 'in' from somewhere and go 'out' somewhere.
I am pretty sure that the crude level of control an ESC does is just "Power up ONE COIL" at a time, and to do that they switch on ONE 'circuit' - that is two wires to the motor, to form that.

To all intents and purposes you may as well say the 100Amps the ESC took from the battery, went down that circuit path. But if you look at it on an Oscilloscope, which will show you the real-time activity at the measured point, you will see a waveform of the voltage - not a constant. So those wires will not be carrying 100Amps continually.... it will be a rising and falling wave and the AVERAGE is 100Amps. That 100Amps is what your "DC" meter will show you - but it can only see an average. Plus, at the battery side there has also been 'averaging' of flows anyway - smoothing by the ESC input Capacitors, and the battery itself even - so it is already almost "DC".
I expect the motor wires would have to have HIGHER than the 100Amps, at their higher ends (to the peaks) of the waveform, to get an average of 100Amps overall.

I guess you could put a 'clamp' type ammeter on a motor wire to measure its Current (Amps), but due to the frequency of the switching (waveform) I think it would have error - even though it will average it out to some degree. Its design/components would probably 'miss' a lot of the waveform portions, as they are not fast enough to 'see' it all, so the average it does see is likely to be amiss anyway.

I have always been amazed at how SMALL the motor wires are on, say, a 28mm motor - versus what the battery lead size needed. WAY smaller.... yet need to carry the same average Amps. Though there are three, so one lead gets some good down-time between phase cycles (33% down time). But I am still not sure about that motor wire thing, and how it seems to matter less.....
I assume they ARE actually all the 'copper' needed (wire gauge) to do their specifications task properly. You would hope...
And then that means the 'larger' battery leads typically used are more to just get Resistance/Impedance down to the lowest possible amount - which the larger you go, the lower that is. But that strategy is not practical to do on motors - for a few reasons.
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Old Yesterday, 04:49 PM
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I'm trying to decide if 4mm bullets are enough for a motor that will pull 100-110 amps... Do you think they would be fine Pete?
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Old Yesterday, 04:53 PM
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TODAY is a perfect sunny, dead calm morning... and still at like that now at 9-00am....
But there was no way to get all the mods done last night. Once they are done I can go any morning that is good weather, but yet to see when that will be. The mods will probably take a few nights (two?).
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Old Yesterday, 05:31 PM
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Quote:
Originally Posted by DamonH View Post
I'm trying to decide if 4mm bullets are enough for a motor that will pull 100-110 amps... Do you think they would be fine Pete?
3 phase motor because each phase is at if memory serves, sees only ~ .7 of total voltage, each wire sees slightly less volt amps meaning that each doesn't experience that total at any one time intentionally.

So easiest way is to tell adequate bullets on the motor side is the gauge of the motor wire of the ESC. But there is no harm in a direct solder or a larger gauge bullet or even using just the female side of a bullet.

If that was your question....
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Old Yesterday, 05:53 PM
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90mm EDF's, which are more typically run in to 100Amps region, generally use 4mm.
I always change to 4mm, if they weren't already, or more often I directly solder the joints anyway.

3.5mm bullets can also be different lengths! Thus have more contact area in a longer one.
4mm seem to be predominantly one length, and it is quite long. Versus the 'short' 3.5mm ones are clearly short little things. So in 4mm I guess that means all forms are pretty well 90A capable.
I have not had a single motor that runs over 120Amps, and most doing 100A max, but direct solder erases a connector aspect anyway.

You don't really disconnect motors that often, so soldering is 'better' seeing it saves connectors (cost and resistance) and does a better job anyway! Versus slightly more difficult to do in situ.
But at least there are no connectors to come off at the field, or in flight! hehe (not that they really ever SHOULD.... but people have had it happen!)
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Old Yesterday, 05:57 PM
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PS: I just kept the DrMad/Lander 3.5mm bullets on the Su-35 motors.
My A-10 motors are soldered.... my Me-262 I forget, but were 3.5mm bullets originally in its 5S setup. Might be soldered now.
(These three (4) twin 70mm jets all use the same power/EDF setup)
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Old Yesterday, 06:20 PM
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Thanks Pete and Max. I was wanting to use 4mm bullets because I have a couple of different set ups (maybe three JetFan, Wemo EVO, and Stumax)that I am looking to try in the FW 90mm F-16 and it would be much easier to swap them out instead of a direct solder joint. Just wanted to get some opinions on whether or not 4mm bullets would be sufficient with the expected amp draws.
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Old Yesterday, 07:01 PM
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I think 4mm bullets are totally fine on your motor for those applications.

Usually 4mm bullets on motors around 2 or 3kW, drawing about 80 - 150A

my heli motors that produce from 4 - 8kW have 6mm bullets

so I think 4mm bullets should be applicable (unless you're going way high power on your 90mm setups)
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Old Yesterday, 07:37 PM
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Thanks teshiecat! I don't think my amp draw on any of these set ups will be any where near 150 amps. I think the highest may be 120ish...
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Old Today, 04:13 PM
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Quote:
Originally Posted by Antaeus View Post
Jandro flies stock, he may be able to chime in on this one.
Just the first 50 flights with Svetlana, may her soul rest in peace.

Never made current tests neither got to do thrust tests before I upgraded to RCLander fans, sorry.


Quote:
Originally Posted by PeterVRC View Post
Wow!! SO FAST... yet could not rotate....
It got to its terminal 'grass speed' within one second pretty much!
Quote:
Originally Posted by PeterVRC View Post
A long walk.. bring it back.... now what???
Hmmm, Spoilerons would help I would think.... but with a TV assisted LEAP to be likely, Spoilerons could make for an even scarier rotation!!
What about Flaperons?? Hmmm, likely to make it WORSE really - driving the nose down even more. But MAYBE airflows would just work out useful to get it to rotate instead. I may as well try.....
Spoilerons WOULD NOT HELP. Really, it's a bad idea. They could help rotation but they kill all the lift. Even if the plane rotates it will have a bad time getting airborne! And if it does, it will be unstable most likely...


Quote:
Originally Posted by PeterVRC View Post
I had been thinking about RAISING the nose leg, but had decided I "would not need that" - hmmm, wrong it seems.
It's interesting that through all your adding-useful-weight modifications you haven't added the most basic known-mods that improve takeoff behavior for this aircraft... (such as the nose gear reinforcement, the nose landing gear height change, struts improvement, etc)

Quote:
Originally Posted by PeterVRC View Post
I was thinking about Jandro's Trailing Link main gear..... and a useful side effect they will have!!
Trailing Link gear 'compresses' FAR easier than straight legs do - due to Trailing Links having pretty well zero friction, whilst straight oleos have quite a lot of friction detracting from their compression ability.
That's true BUT just as the norm. My oleos are pretty hard in fact. I mean, they work smooth but they just don't compress under a simple bump in a takeoff run. They are there mostly to be able to absorb a strong impact on a bad landing but you can picture the plane tumbling constantly when it travels on uneven ground. The struts do not adapt to it, they feel pretty rigid (Unlike the nose LG). The struts of the Eurofighter show a behavior more akin to what you are describing but those are insufficient for a 3,6kg plane. (I can tell frommy experience with them on the SU-35).


In my humble opinion, I would start by adding the basic mods that the rest of us already use with good results (Being that to increase nose LG height AND to rotate the nose strut forward so that the friction with the ground makes it stand vertical or almost. It's a better position to withstand impacts also), then I would reinforce also the front of the battery bay (As shown many times in pictures here, with balsa wood and epoxy) and finally adding flaperons on take off. THEY DO HELP, I can tell for I have used them and it softens the take off. They do not have such a strong pitch down contribution as you might think. It might surprise you but you should consider that the wake deflection they generate induce a sharper AoA on the tailerons, meaning the tailerons want to push up the plane more when flaps are deployed. In any case, what would be ideal is to trim the elevators for deployed flaps in the air before using them for take off. But since you find so much trouble getting airborne you might consider it.
I would also advise you to setup 2 or 3 separate flight modes on the Taranis so that the trims for normal flight, take off and landing (with their particular flaps, brakes, stab trims and landing gear position) are stored separately. This way you can change from one mode to the other and conserve the trims. That is overly useful.

Good luck on next try!
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Old Today, 06:17 PM
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"Spoilerons WOULD NOT HELP. Really, it's a bad idea. They could help rotation but they kill all the lift. Even if the plane rotates it will have a bad time getting airborne! And if it does, it will be unstable most likely... "

You should actually DO things like this in real life rather than more likely quote theory. Your "All" is total rubbish..... it won't even lose 15% of lift!! Plus you say "all" and then say "It will have a bad time getting airborne" - if it loses ALL lift it would never get airborne, LOL.
And it is NOT even"unstable" (Spoilerons) it is actually a MORE stable state (explained later).

More importantly is that LIFT does not even truly come from "Bernoulli" form so even with maximum Spoilerons a 'flat plate' with angle of attack will still LIFT totally fine. It is just less efficient - not ALL GONE.
As a matter of Reference.... I land my SBach with max Aileron Spoilerons. What that does is:

1) Deployment cause a HUGE rotation to higher AoA - but you have a LARGE Down pitch mix with them, and they are all on "slow" so it takes 2 seconds to complete. This is to prevent sudden mis-aligned pitch result - you can manually correct it to remain at the flight path line you want. The end result is something like a 15deg AoA for approach.

2) As that AoA increase turns up it has MORE lift than before! That is why it flares nose up, and even climbs! The greater AoA easily swamps out the loss of "Bernoulli" based lift. The 'Newtonian Reaction air hitting a surface' form (or NASA's 'flow turning' name) create far more lift than was lost.
If you were flying a typical above stall speed (which you would be when you do this), it will CLIMB unless you added Down pitch control.

3) The DRAG goes up a lot... not from the Spoilerons to any degree that matter (negligible) but from the greater AOA! The large angle the wings are at to airflow now. This is fine when landing as you WANT to lose speed. So the overall result is exactly what you want/need... more AoA... speed reduction.... and maintained level flight, into a glide slope for approach - which is of course Power determined.

4) An extra great benefit is that any plane with Drag, needing POWER to overcome, is "Tensioned in space"... and that makes for a far more stable vehicle. The same reason racing cars Trail Brake into turns (good racing drivers anyway). So now you have a slowing plane - that is controlled by Power, which means you have BRAKING ability too (reduce Power) even if it is descending(!), and it is a very stable 'tensioned vehicle'. You can control the exact touch down point with a huge amount of control - via increasing or decreasing speed easily.

Then on a take-off I often do that same process - half because sometimes I just forget they are up, other times just to take off SOONER - seeing my wheel spats are 'fragile' and easily break if the grass catches them.
The runout still acts just like normal... tail comes up before it lifts off - which that rate of is more power increase dependent anyway really, but it can go airborne at a much lower speed and sooner. That is really because of the way its 'tuned' natural state of +15deg AoA (made for landings) means it also does that 'automatic' AoA as soon as the wheels leave the ground and lose their input factor to the plane's AoA.
Basically, for landing OR take-off, the Spoilerons are an 'automated AoA creator'. Because you have made a CURVED VANE out of your wing. A curve that drives it UPWARDS.

It works totally fine.
This is because the lift available is TONS more than required anyway, so the trade off of some loss of lift, for much greater rotation ability, is no issue at all. I have done it fine on other planes... but would NOT on a maiden!! It causes very notable rotation - nose up if in flight - so if a plane was to 'leap' off the ground into some steep climb, that would be massively worse with Spoilerons! And the faster it goes the more rotation they cause! So it will escalate as the acceleration increases the speed.
I was not fussed about my Su-35 not being able to climb even towards 90deg right away, but NOT to possibly do some back flip with an unknown plane quantity! It probably wouldn't have done that, but COULD.... thus not a risk worth taking.
You can try it on a KNOWN flying plane, but it would be risky to try it on a unknown. Especially one KNOWN to LEAP into the air!
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Old Today, 06:39 PM
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Oh, and that "automated AoA" is another big PLUS of using Spoilerons to land. Just a tuned mix makes a plane that you do almost NOTHING to get it into a nice Positive AoA attitude. It is much harder to set that up using Flaperons or Flaps - though if you have true Flaps (inboard devices only) then they can be set up well too. There is a different sequence, and reasons, why Flaps work well too. Plus they have an added benefit - thus you use those IF you have them. But it is NOT the same for Flaperons!

Thus why a SBach, or this Su-35, with Full Length Ailerons, is best suited to Spoileron use.
But having said that, I would probably STILL use Flaperons to land this (and do on Su-35-01) because it has a tendency to flare up anyway. If it is USEFUL then Spoilerons are there, but for scale reasons when things are NOT important, Flaperons are fine.
But for the TAKE OFF issue, Spoilerons are the best option to get it off grass. Flaperons are a detriment then!

It is actually a near IDENTICAL case of using Upwards LEF's!! Both methods get an UPWARDS CURVE in the 'vane'...the wing. As a wing is really just a vane anyway - which is NASA's main terminology for it. An airflow "TURNER". I agree with that, but I still prefer to view the 'Newtonian' aspect of it as dominant. Even if it isn't, it is still at least the second most dominant (way over Bernoulli), and is even a 'joint' portion of the 'Airflow Turning' idea anyway.
Upwards LEF's act MORE in the Newtonian aim right from the start of motion, whilst Upwards Ailerons (Spoilerons) act more in the 'vane' aim BUT almost immediately then CREATE the Newtonian state - because you moved the wing to greater AoA!! So 'Turning Airflow' CREATES that Newtonian state anyway! The Turning continues - as long as the 'curve' is there (whether an Aileron, Elevator, Rudder) - but the instant Turning occurs, Newtonian steps in too!

I thin I just dislike that "Turning" name.. it sounds a bit silly. But I do believe in its action/reaction.... it is totally valid and true. So really, you want to believe in BOTH of those forms of "Lift". And to all intents and purposes can totally IGNORE Bernoulli.. seeing it is a VERY MINOR player in it all.
PS: A curved wing surface CAUSES TURNING also!! And just for more information.... a SYMMETRICAL wing works because of BOTH those reasons above. It NEEDS an Angle of Attack to even work at all, but doing that means it is Turning the air off the top curve, and creating the Newtonian Lift off the bottom surface (hitting airflow). So when the plane goes upside down all it needs to do is move to the same opposite Angle of Attack and it will work 100% the same as when the
plane was upright.
Whereas a non-symmetrical wing won't be the same for upright and inverted. When inverted it loses the Turning effect seeing the top is now FLAT. So of course any plane intended to fly inverted also will sue a symmetrical wing profile!
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