Warhead 27k short shaft. I need convincing...

[Egon_247]

Yeah, i know, me again. Sorry. This ones bugging me a bit though.

So. I'm not sure i can justify £110 on a motor for one of my pews. I've put it in my basket, out my basket, in again etc. , but part of me is really concerned.

Granted they've had rave reviews and they've cured world peace or something like that but I'm worried about dropping a ton on a motor.....

Would a 27k make a noticeable difference? I'm running a standard high torque on a 7.4v lipo (yes, it has mA and C but I cant remember what, as I'm at work and my pew isn't )

I've done the usual gearbox stuff (gears, shims, grease piston blah blah) would a 36k cause pre engagement or am I overthinking it? 

The pew in question is a TM Aug (with replaced cheese gears). 

£110 is a days pewing with the boy and not sure i can justify it unless you lot convince me..... 

View attachment 123635

 

[Pseudotectonic]

What motor what gear what spring what BB what barrel length?

 

[Egon_247]

What motor what gear what spring what BB what barrel length?

Warhead BASE 27k, 18:1 (ss by 1 tooth) M100 lobbing 0.28g' down a 450mm 6.03 .  

 

[Pseudotectonic]

Ok that is quite a standard build so there is no crazy torque requirement to worry about which is good

With 18:1 you can estimate your "paper ROF" with 27000 x (8.0/11.1) x 1/18 x 1/60 x 78% = about 14 RPS max

(8.2 is because a fully charged 7.4 we can assume around 4.1 V per cell give or take)

(The 78% is a universal constant for efficiency loss I find pretty spot on for all the Warheads)

So you still have plenty of headroom until PME which is say just below 30, say 28+ RPS

In reality you can try the Base 45k which will draw about the max amp your 7.4 is able to power anyway which should give you in the region of low 20s RPS which is still plenty of headroom below PME ceiling so the 45k would still be fine with your setup

 

[Hatchet]

Depends why you want it really. They're great for turning over any spring, getting the most out of batteries, etc. I've not had any issues running 27k on 7.4v, but depends how many RPS you "need".

The only point worth noting (other than worrying about soldering wires onto an expensive motor so it'll go in an AUG), is that there are lots of options for making a slow motor faster (16:1, 13:1. 12:1 gears, which this will have no problem turning over) or 11.1v batteries, but there aren't as many at slowing down one that's too fast...

 

[Egon_247]

Depends why you want it really. They're great for turning over any spring, getting the most out of batteries, etc. I've not had any issues running 27k on 7.4v, but depends how many RPS you "need".

The only point worth noting (other than worrying about soldering wires onto an expensive motor so it'll go in an AUG), is that there are lots of options for making a slow motor faster (16:1, 13:1. 12:1 gears, which this will have no problem turning over) or 11.1v batteries, but there aren't as many at slowing down one that's too fast...

Well, there's a daft story behind that. The guy that got me into airsoft has just gone to HPA. At which point i realized the aeg's in my collection are making too much noise when i pull the trigger. So, faster motor and then maybe faster gears. Moar speeds, less noisy.  

I ran it on an 11.1v for ONE GAME and realized that 22rps was not my kinda speed. Semi is my thing. (OOER!) 

I may try the 6.00 barrel i got from AK2M4 at some point but i guess that'll poke me over the limit...  

 

[Sewdhull]

Brushless motors will keep the current draw down, even when they are on stiffer springs.

Mechanically they are quieter and with only the bearings as a wear item, likely to last forever.

They have bags of torque partly because they are electronically commutated (probably variable timing) and partly because there are more poles and room for more copper.

The bit that makes the heat is on the outside so they run cooler and the magnets are better shielded from the heat. You battery will last longer in a day but also have a longer lifetime.

Ther are expensive only because few people use them.

I'll be looking at ak's when they are in, I have an adv one I haven't used yet.

 

[Egon_247]

Ok that is quite a standard build so there is no crazy torque requirement to worry about which is good

With 18:1 you can estimate your "paper ROF" with 27000 x (8.0/11.1) x 1/18 x 1/60 x 78% = about 14 RPS max

(8.2 is because a fully charged 7.4 we can assume around 4.1 V per cell give or take)

(The 78% is a universal constant for efficiency loss I find pretty spot on for all the Warheads)

So you still have plenty of headroom until PME which is say just below 30, say 28+ RPS

In reality you can try the Base 45k which will draw about the max amp your 7.4 is able to power anyway which should give you in the region of low 20s RPS which is still plenty of headroom below PME ceiling so the 45k would still be fine with your setup

Damn son. If i had a hat on, i would doff it to you sir.

Thank you for the reassurances.

 

[Duff Beer]

Don’t know if it’s entirely useful information, but I run a Warhead Standard Black on a base set of gears and a 9.9v LiFe and it’s pretty bloody snappy and very efficient on battery life.

For me, before everything a Warhead Motor is now the first upgrade before anything else

 

[Leo Greer]

As a note, brushless motors have a lot more torque than brushed. This varies with build and motor, but, as an example, The T238 brushess motor I use in my main build runs at about 99% efficiency (shooting 1.5J), rather than the more typical 80%. I can also highly recommend the T238 brushless motors. I use two, and have a few hundred thousand cycles combined on them. I've had no issues (yet...), and have found that their pinions mesh beautifully with both stock style Chinese/XYT sets, and "upgrade" sets such as SHS.

Are they worth it? That depends entirely on you. For my purposes, the answer is yes. They don't go in every build, but on my go to replica that I pick up and play with constantly, the low power draw, no heat, smooth cycling, and reliability is nice. But, of course, they cost 3x a normal brushed motor that'll do just fine, and 1.5x a really nice brushed motor like a Tienly. It's all up to your personal opinion.

 

[Sewdhull]

I also like the t238. Reapers did some comparing and the warheads used less current but they may produce less torque...

My take is if you are going to get a really good brushed motor get a brushless instead.

 

[Egon_247]

Well, I've taken on board all of your advice and gone for the 27k base. I did hover over the Uber silly one but then I quite like sleeping indoors...?

 

[Sewdhull]

There's not a vast difference between the base and the Ronin.

There's a big difference between the base and and a brushed motor.

Do have an ETU?

 

[Egon_247]

It's going on my trouble child AUG. 

It's got a cheap n cheerful mosfet....

Got the boy to test it today ready for the motor to go in. Made an odd noise so thought I'd investigate before unleashing a warhead on it...

Thankfully had a spare one from a set I'd bought. Sheesh. These toys eh? ??

View attachment 123895

 

[Pseudotectonic]

Curiously the Warhead motors have about 10 ms starting delay, could be software related, because they also seem to have some sort of throttle control for those soft ramping amp draw (source: https://www.youtube.com/watch?v=QZozpvzYNQI )

This could be their "secret sauce" for making it as efficient as possible, by sacrificing a little bit of performance at the spin-up.

That and the fact that I have to buy a bottle of high strength retaining fluid just to install the pinion gear (and wait 24 hours for it to cure) makes it a no-go for me.

If I were to spend money on a brushless I would get any other brushless but not a Warhead.

Also, in terms of torque, my observation from watching countless video is I think brushless are no better than a 28 TPA motor for trigger response. Curiously I just dug out the actual numbers and it confirms my suspicion:

Chaoli's brushless gives 401.8 mN.m at a cost of 156 A

https://www.aliexpress.com/item/1005006432563689.html

Chihai's candidate gives 416 mN.m at a cost of 162.5 A

https://www.aliexpress.com/item/1005006352513842.html

a 28 TPA gives 395.65 mN.m with merely 66.875 A

https://www.aliexpress.com/item/4000757781793.html

And look at this 18 TPA cutie they just came out which gives a whopping 5123.3 mN.m for 167.3 A

(I am sure it is a wrong label and should be g.cm rather than mN.m so if it is around 500 mN.m maybe it could compete with brushless if one were to force feed it current) but this does have upgraded magnets

https://www.aliexpress.com/item/1005006433968020.html

I know brushless are more efficient generally speaking, but I still think the higher torque brushed motors are still better (for trigger response), because they have no software issues (e.g. with ETUs) to worry about and and there is no 10 ms boot time delay or other nonsense, you feed it current and it just works.

But of course they have higher RPM ceilings and compared to brushed motors with similar RPM they do have better torque. I am just saying, I guess they don't have extra torque more than the highest torque brushed motors.

 

[Leo Greer]

The 10ms starting delay is likely because of startup torque. Brushless motors have a lot of instantaneous torque and have even been known to snap their drive shafts without a ramping program.

Of course if you're using a 28TPA you'll have more torque. If you used a brushless motor of the same speed you'd have more torque. I used a 33K RPM T238 to pull an SP170 spring (M190 equivalent) in a DSG build and it still performed at high efficiency. Good luck getting a brushed motor of similar RPM to perform the same. Also, torque is not everything. Trigger response is still limited by the maximum RPM of the motor. For example, I have a 38TPA motor that runs about 15K RPM on 11.1v. Even using 12:1 gears, the trigger response is slow. Hence, I use a 14.8v to up the RPM.

 

[Sewdhull]

Reapers Airsoft have measured some cycle times for motors.

Brushless do well in all categories

             Current/Peak  Cycle Temp

Base 35K      22A/43A 45ms 33C

Tiernly 30K.  37A/78A 52ms 46C

 

[Pseudotectonic]

@Leo Greer Is your 38 TPA this one? https://www.aliexpress.com/item/1005001389831124.html

Yeah saw a video that tested it, it sounds surprisingly slow indeed

Curiously it only has a stall torque for about ~230 mN.m for ~33 A which is substantially lower than the 28 TPA, looks like while it is technically more efficient (more torque per current) but it seems it simply cannot make full use of the amount of currents we can afford in airsoft

Interesting use case for a 14.8

@Sewdhull I take Reaper's "cycle time" with a grain of salt because they don't explain their methodology (maybe they did but I don't speak German) and judging from other trigger response videos floating around, and the 10 ms delay measured above, I suspect their cycle time is taken from a string of full auto divided by the number of shots, because in my head Warhead would be behind a few other brushless (and not at the top of the chart) if it is only measuring the very first shot, which is more important for trigger response

Similarly their current chart looks about right, but it doesn't show whether it is semi or full auto (and for how many rounds), and whether their 11.1 is fully charged (i.e. more than 11.1) or at exactly 11.1 measured with a meter, and if they were not through in making sure the battery is at exactly the same voltage before the tests, it can affect the numbers

Also different capacity of 11.1 batts will have dramatic differences of Vdrop under load, which can affect trigger response and cycle time

So while their charts are good references I have some doubts about their cycle times and I am not sure Warheads have better trigger response than the other brushless as the chart implies

 

[Sewdhull]

Turn on subtitles, it's explained it is one cycle but the data comes from a titan gate, so...

It's just a comparison.

There is very little that shouldn't be viewed critically.

The absolute numbers I think are less relevant than the trend.

All brushless will have a delay, as will all ETUs, how much will vary by the software in the motors.

Lipos at the sort of currents here are much of a muchness so long as they are nearly full.

There are some lipos that really aren't suitable, but generally they are good enough.

Brushless motors are new in Airsoft and unusual because the motor has a controller inside it.

I think the ideal would be controller in the ETU and the brushless motor bare like in drones for example.

I forget who already does this in Airsoft...

 

[Leo Greer]

As far as I'm aware, there aren't any ETUs w/ brushless controller included. We really only have a dozen or so makers of brushless motors for airsoft... if there was I'd be in.