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May 18, 2016, 03:39 PM
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The Emax 1804 are a nice little motor. They have to be better suited to spinning 5” props over 1306s with the extra torque from the 23mm diameter. At 14 grams, are only a gram heavier than the DYS 1306. The bearings haven't lasted too long, there's a little play in all of them now, I don't think 2mm shafts running 5” props help. They get almost daily use but I was hoping for a little more life out of them. The quad is OK at low throttle but sounding rough at WOT now.

The current thrust to weight ratio of the X2 is 5.3:1. I really want around 8:1. My Warpquad 230 is 8.4 :1 (Cobra 2204/2300 on 1000 3S, HQ 6 x 4.5) and I want to recreate that initial punch and acceleration in a lightweight 5” quad, not bothered by top speed at all. Assumimg I can lose 20grams over the X2 with the new frame and build, and another 15 grams with some smaller high C 500mAh 3S, this should bump the thrust to weight up to almost 7:1

I've got some 2800kV 1806 motors planned to eventually replace the Emax 1804 on the X2. This should give me the 8:1 although at the detriment of higher AUW.
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May 26, 2016, 05:17 AM
Forward ever, backward never!
Brainstorm's Avatar
Quote:
Originally Posted by TimR74
The Emax 1804 are a nice little motor. They have to be better suited to spinning 5” props over 1306s with the extra torque from the 23mm diameter. At 14 grams, are only a gram heavier than the DYS 1306. The bearings haven't lasted too long, there's a little play in all of them now, I don't think 2mm shafts running 5” props help. They get almost daily use but I was hoping for a little more life out of them. The quad is OK at low throttle but sounding rough at WOT now.
Interesting notes on the Emax 1804, Tim. Agreed on the torque part. I think 1804 are to 1306 like 2204 (brilliant) are to 1806 (crap).

I seem to recall that quality and durability was a bit of an issue with the RCX/ZMR 1804 two years ago as well. I guess there's only so much you can do for durability at this micro scale, especially at these bargain prices. If you're willing to pay 4x price for Tiger motors, they are generally much better quality. But given the abuse we put them through, it's hard to justify.

Quote:
The current thrust to weight ratio of the X2 is 5.3:1. I really want around 8:1. My Warpquad 230 is 8.4 :1 (Cobra 2204/2300 on 1000 3S, HQ 6 x 4.5) and I want to recreate that initial punch and acceleration in a lightweight 5” quad, not bothered by top speed at all. Assumimg I can lose 20grams over the X2 with the new frame and build, and another 15 grams with some smaller high C 500mAh 3S, this should bump the thrust to weight up to almost 7:1
Definitely sounds like you're on the right track! Personally, I'm not able to take advantage of these high thrust-to-weight ratios. So I'm perfectly content to fly slightly portly, but durable builds. WQ230 is very hard to beat for both thrust-to-weight and durability. But that's obviously a larger/heavier 6" frame than the 5" frame you're working on here.

Quote:
I've got some 2800kV 1806 motors planned to eventually replace the Emax 1804 on the X2. This should give me the 8:1 although at the detriment of higher AUW.
To be honest, I don't like the 1806 motors. They're essentially the same weight as a light 2204, e.g. SunnySky. So like you've favored 1804 over 1306, I would favor 2204 over 1806. You'll get much better torque as well as better cooling and thus less heat buildup. Of course, you already have the 1806, so you might as well put em on and fly.
May 26, 2016, 09:56 AM
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Quote:
Originally Posted by Brainstorm
To be honest, I don't like the 1806 motors. They're essentially the same weight as a light 2204, e.g. SunnySky. So like you've favored 1804 over 1306, I would favor 2204 over 1806. You'll get much better torque as well as better cooling and thus less heat buildup. Of course, you already have the 1806, so you might as well put em on and fly.
I agree with your points on lightweight 2204 (like the Sunnyskys) against 1806 motors.
My reasoning is that I want to stick with 3S - I have loads of good 850mAh 3S batteries and small (500-700mAh) 4S LiPos seem to be non-existant in the UK. The kV on the Sunnyskys are too low at 2300 to get decent thrust for the weight from a 5x3 or 5x4 prop. The SS 2204 on 3S makes 460 grams of thrust with a 5x4. The Cobra 1806 or T-motor F30 (both 2800kV) make 590 grams.
May 26, 2016, 11:41 AM
Forward ever, backward never!
Brainstorm's Avatar
Makes sense! I'd didn't realize the 1806 were available with 2800KV now. If max KV and max thrust are your goal, it sounds like these high-potency 1806 will serve you well. It'll be interesting to see what kind of thrust the motors and 3S 850mAh packs can sustain.

Given how light you're making this frame, lower torque and cooling (compared to 2204) should be a non-issue. I think most of the complaints about 1806 were from people using them on heavier mini-H quads for FPV, not LOS acro. Good fun!
May 26, 2016, 12:28 PM
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That is absolutely beautiful in its simplicity Tim, I love it.

I've been thinking of doing something very similar for a 230 sized frame using the square wound carbon tubes from Flyduino as used on the MiniCP120 but I like this better... this is probably even lighter and stronger despite the choice of pultruded round tubes.

I have a few questions if you don't mind..

How do you tighten up the motor bolts?
How did you cut the notches on these?
Do you think cutting/sanding some nylon spacers to fit snugly inside the tubes where the bolts go through, would add a lot of strength... or is the weakest point in the frame elsewhere?
Last edited by Ari33; May 26, 2016 at 12:55 PM.
May 26, 2016, 03:27 PM
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Brainstorm, that's the plan, just waiting for the F30s to come into stock…...

Hi Ari,
Thanks for the comments. I like the simpilicity as well, the quad frames really are dead easy to build accurately, reasonably quickly and cheaply. I've used woven tubes for the arms on the X2 and X3 (only pultruded strip on the X1). Pultruded tubes are not a good idea for arms as it doesn't give you the multidirectional strength needed, as I'm sure you know.

Round tubes are not as stiff as square tubes, like those used in the Warthox mini CP. Having worked with moulded RC gliders and seen the lengths people go to for a minute bit of drag reduction and increased efficiency, I don't think I could bring myself to use square tubes! Not that it would make any difference for my level of flying, but hey.

With mounting the motors, I have 2mm holes and the bolts running through both walls of the arms. Structurally, a lot more sound than through just the top wall. I filed a very small flat under the bolt head. Will take a quick pic.

Regarding the weak point, the 1804s are only mounted with M2 bolts. If a motor took a hard hit, I highly suspect the bolts will either shear or the threads will pull through. I've probably had hundreds of crashes now, all the bigger ones onto soft grass though, with no motor damage (can't be good for those 2mm bearings!). The end of the arms take the brunt of the crashes.

A 230 or bigger frame, with 2205-2206 motors, will put a fair bit more stress around the motor area. There's not a lot of info around on the mini CP, with the same 1mm wall thickness, and how the motor mounting copes with crashes….

I've actually just started chopping up some tubes for a bigger, superlight but strong 250-270mm quad with 2205 motors. I'm planning on using the same 10x8 tube for the arms and motor mounting method but will reinforce the outer end (under the motor) and the the root of the arm with some bonded internal 8x6 carbon tube. I'll also add a simple shear web to tie the top and bottom centre plates together. Will still be very simple and quick to make. I'll post up some pics when I have a bit more time to get it done. I did consider separate replaceable arms with Warpquad or Mini CP centre plates but you get a lighter, stiffer, stronger frame with an all bonded design it's just that when it does break…..

Replacements are easy to build tho, and I quite enjoy the refinement process of improving the design after any failures.

Would be interested to see some pics and info on your planned scratch build, is it for the ZMX v2 2205s? Feel free to post anything here if you want to. Be good to have a dedicated scratch build LOS quad thread
Last edited by TimR74; May 27, 2016 at 08:10 AM.
Jun 08, 2016, 08:22 AM
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Received some hardware in the post for the new frames.

For my lightweight build, I've acquired a Furious Pico BLX flight controller.
Amazing little thing - F3 Processor with built in 50A PDB, all in a tiny 20x20mm format for the hefty weight of 2.9 grams
This should really tidy up the birds nest of wiring loom and ESC wires I currently have, as well as saving a good few grams.
I thought this deserved a new frame, so have started on a super slim X4 frame with 6x4mm arms. This may be pushing the limit on the tubular arm size reduction, but we shall see. I've taken the easy, lazy option of some ready cut centre plates, which are just 1mm carbon FC cover plates.

The long awaited Littlebee pro 4in1 ESC has also arrived. Unfortunately the T motor F30s to accompany it probably won't be available until the end of the month.
Last edited by TimR74; Jun 08, 2016 at 08:33 AM.
Jun 08, 2016, 12:49 PM
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Quote:
Originally Posted by TimR74
Received some hardware in the post for the new frames.

For my lightweight build, I've acquired a Furious Pico BLX flight controller.
Amazing little thing - F3 Processor with built in 50A PDB, all in a tiny 20x20mm format for the hefty weight of 2.9 grams
This should really tidy up the birds nest of wiring loom and ESC wires I currently have, as well as saving a good few grams.
I thought this deserved a new frame, so have started on a super slim X4 frame with 6x4mm arms. This may be pushing the limit on the tubular arm size reduction, but we shall see. I've taken the easy, lazy option of some ready cut centre plates, which are just 1mm carbon FC cover plates.

The long awaited Littlebee pro 4in1 ESC has also arrived. Unfortunately the T motor F30s to accompany it probably won't be available until the end of the month.
You don't really need a PDB if you have a 4-1 esc, I think! But the current sensor is cool. Where did the plates come from?
Jun 08, 2016, 12:52 PM
Registered User
Quote:
Originally Posted by TimR74
Received some hardware in the post for the new frames.

For my lightweight build, I've acquired a Furious Pico BLX flight controller.
Amazing little thing - F3 Processor with built in 50A PDB, all in a tiny 20x20mm format for the hefty weight of 2.9 grams
This should really tidy up the birds nest of wiring loom and ESC wires I currently have, as well as saving a good few grams.
I thought this deserved a new frame, so have started on a super slim X4 frame with 6x4mm arms. This may be pushing the limit on the tubular arm size reduction, but we shall see. I've taken the easy, lazy option of some ready cut centre plates, which are just 1mm carbon FC cover plates.

The long awaited Littlebee pro 4in1 ESC has also arrived. Unfortunately the T motor F30s to accompany it probably won't be available until the end of the month.
I've noticed titanium tubing is pretty cheap and I think it takes epoxy well. For sure it will take a crash better that CF or Au
Jun 08, 2016, 04:51 PM
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Quote:
Originally Posted by sonic_boom
You don't really need a PDB if you have a 4-1 esc, I think! But the current sensor is cool. Where did the plates come from?
Yeah I know the Pico BLX fc and 4in1 Littlebee (both have built in PDBs) are intended for separate frames.

The centre plates are the top cover plates from the Raptor range of quads.

I did have a quick scout around for some titanium tubing a while back. Strong stuff but still more ££ than carbon and tricky to work with. The 10mm carbon frame is plenty strong enough for my needs in a 5” quad, and only weighs 31 grams. I want to push the lightweight theme and find out where the acceptable limits are.
Last edited by TimR74; Jun 08, 2016 at 05:00 PM.
Jun 08, 2016, 07:17 PM
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Quote:
Originally Posted by TimR74
Yeah I know the Pico BLX fc and 4in1 Littlebee (both have built in PDBs) are intended for separate frames.

The centre plates are the top cover plates from the Raptor range of quads.

I did have a quick scout around for some titanium tubing a while back. Strong stuff but still more ££ than carbon and tricky to work with. The 10mm carbon frame is plenty strong enough for my needs in a 5” quad, and only weighs 31 grams. I want to push the lightweight theme and find out where the acceptable limits are.
if I didn't make a mistake, 450 mm worth of titanium 8 mm 1mm wall tubing should be about 10 g. Mounts probably not needed? Drill and squash. I think titanium is pretty good with Epoxy too.

8mm tubing should be also light and absorb and rebound much better in a crash. It will be less stiff, but with the short lever, you might have extra stiffness with carbon that you didn't need.



http://www.ebay.com/itm/1PC-Titanium...YAAOSw~oFXNCEa

http://www.ebay.com/itm/1X-Titanium-...wAAOSwwPhWiw2O
Last edited by sonic_boom; Jun 08, 2016 at 07:32 PM.
Jun 09, 2016, 09:48 AM
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I think you did make a mistake , a quick Google shows that 8mm O/D with 1mm wall thickness is .099 kg/M (assuming average density of titanium at 4.5 grms/cm³). So the 50cm tubing needed would be 49 grams.

It does also work out at over 5 times the cost of carbon. But as you say, it would certainly make a tough frame.
Jun 10, 2016, 08:35 AM
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Quote:
Originally Posted by Brainstorm
To be honest, I don't like the 1806 motors. They're essentially the same weight as a light 2204, e.g. SunnySky. So like you've favored 1804 over 1306, I would favor 2204 over 1806. You'll get much better torque as well as better cooling and thus less heat buildup. Of course, you already have the 1806, so you might as well put em on and fly.
Brainstorm - Going back to your point about lightweight 2204 motors, I've ditched the idea of higher kV 1806 motors now for the heavy 5” quad. Just ordered some Gen 2 2204 Sunnyskys you'll be pleased to hear

Constantly keep changing my mind about different setups. After further research, I'm going to try some 5x4x3 props on the 2204s on 3S. They should make similar thrust to the higher kV 1806s on a 2 blade prop. From what I'm reading, it's all about the motor torque/prop blade grip and resultant control it produces that makes these copters fly so well. Need to get this efficiency thing out of my head.

Secondary benefit of this, to me, is the lower rpms and hence audible pitch. Love the ‘whoop whoop’ sound of 6x4.5s at low rpm when blipping the throttle. When small props start spinning north of 20k rpm I find the ‘scream’ gets a little irritating
Jun 10, 2016, 10:12 AM
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If you are ever in the look out for lightweight monster motors check out the ZMX v2 2205 2300Kv, SHT N52 magnets, produce over 1200g of thrust on KK6040 and weigh only 26g.. even with the long uncut motor wires.

http://www.miniquadtestbench.com/zmx...05-2300kv.html
Last edited by Ari33; Jun 10, 2016 at 10:21 AM.
Jun 10, 2016, 04:28 PM
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Thread OP
Yep, I've already checked out the ZMX V2s, impressive motors. Good to see curved magnets coming in on multirotor motors, minimise that magnet to stator gap.
Will keep them in mind for the 6” scratchbuild when I get these 5” ones finished.


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