As the Het is more or less a copy I would go for the wemotec.
Claus

Originally Posted by Erik v. Schaik

How much power can it take in the wm300 and how many cells?

br,
Erik

The WM300 runs about 1100W with 4600kv on 4S. 2950kv should be good on 6S or more! (the WM400 Mk2 pulls in the neighborhood of 80A on 6S with 2900kv).

1100W at 4s is not good enough: approx75A.No slim controllers can be places in front of the ducting. For 6s this equals to 3066kV/50A which is a better match. I am looing for a motor to match the Jeti Spin55 (55A/8s) which should be about 1700w or so.

yes, because of Cg issues preferably in a wm300.

Pic shows cut down fan of an other brand

Erik,
Have you considered the Mega F5D (2470kv) for the WM300 ?

http://www.effluxrc.com/MEGA-F5D-green-MMF5D.htm

Originally Posted by efflux RC

Erik,
Have you considered the Mega F5D (2470kv) for the WM300 ?

http://www.effluxrc.com/MEGA-F5D-green-MMF5D.htm

This might be usefull, but I cannot do math with fancalc on a wm300. Do you happen to have some testdata? Without load this makes 72k rpm Might be 65k in real life? sounds interesting tough to reconsider making a testbench.

I was orientated to the 16/15/2 and 16edf because of the low inner resistance. F5D is very close to them. Not sure if this needs 7s or 8s. I need an even cell count in my design.

best regards!
erik

Originally Posted by Erik v. Schaik

This might be usefull, but I cannot do math with fancalc on a wm300. Do you happen to have some testdata? Without load this makes 72k rpm Might be 65k in real life? sounds interesting tough to reconsider making a testbench.

Erik,

Some have run the WM400 up to 70k rpm, although I wouldn't suggest it. 65k rpm on the WM300 shouldn't be an issue, provided you balance everything.

The Velocity-RC WM300 / 4600kv calculates to 68,080 rpm no load on 4S. You shouldn't be pushing it much further with your combo. I should have some data from a Castle logger in a week or two. This will be with a custom 38mm dia thrust tube.

Brian

Hi Brian,
I doubt the loaded rpm will be a tad more than the 4600kV/4s setup you are suggesting. The Voltage sag is less and kV is approx 7% higher and high C-rated cells can make a big difference. I'd have a bad day if the f5d motor loads over 55A. That would ruin a perfect match. But IF that motor would fit the Spin55 I guess it will outperform an f5d pylonracer. That would be awesome!
If the load will be too high I need to reduce the fan dia which isn't what I planned but i am open for that if needed. an additional increase of rpm is evident.

I think you understand by now the Uriah-BU concept isn't flutter proof for these power levels. because of this all linkages and centered wingload needs to be revised.

hehe, ot even sure what flight speed I'd expect but I recon it will be going to extreme.
on the Uriah I added a mylar thrusttube inside the original tube. The higher efflux results in airgun/turbine woosh big time in accelleration. at full speed the noise is less. Science shows we need a very high efflux to keep the motor loaded at full speed. If efflux=fight speed the motor would not be loaded=no power. because of this i don't think the 350kmh efflux measured on the testbed will be good enough for 200+mph because of low thrust to cover drag of the airframe.

I am looking forward to your measurements! i am not in a big hurry now. I plane to build up my kitcar in winter if several %&%$ vendors send to me what I've ordered 10 months ago...
So I'd thought let's do something usefull

Finished the Destiny. Hope to maiden her tomorrow!

br!
erik

Originally Posted by MikePS

Thanks guys. Any feelings about the HET 6904 unit vs the WeMoTec mini?

both are good fans and tops in my book for the 70mm class. i personally prefer the wemo and feel its a better design. het will pull slightly more amps.

6904 rotor came lose from a shaft several years ago. I could't make it a hard bolted fix because of wobbling issues. similar issues have been reported on this forum, even facial damage (nose, eyelid). The wemo is more balancing friendly. The wm400mk1 seems like roullette for me: 1 very bad wobble, 1 useable fan. MK2 versions were both to hard to balance. Hope this will be sorted by now on the wm300 I am looking for. I guess because of this i didn't use a wm300 on the Destiny tough it is my favourite igv concept.

Erik,
I see Brian stepped in to assist you. Thanks brian.

I was in Palmdale this morning watching (and filming) the 200" altitude runway pass of the piggybacked space shuttle at Plant 42, were they were assembled.

I don't have any test data on the F5D other than the factory specs.

The issues with the HET rotors not being able to be fully tightened, was corrected a couple of years back.

Because you are a distributor of Velocity, can you confirm the adapters of the VM fans are running true by now? Many had wobble issues on this, including myself.

Maidened the destiny today. At 650W power it flys pretty fast, but not as fast as expected. This proves to me the plane needs to be small for high speed and perhaps a cut down fan may not be as efficient as expected. The efficiency might be lower in the WM300 fan as well because this is a cut down WM400. The good news is the 16edf was just warm after flight and the 40A controller doesn't show issues with 5A overload. I think this motor could be used as 5s or 6s in 60mm edf which is nice and light for a high power 60mm setup. It might even be pushed harder in a VM300 fan!

The nacelle+motor+Esc is only 180gr.

I am in doubt if it is worth reconsidering to increase power in this airframe. 2x 4sXPS2200(30-50C) fit snug in this fuse, but Rx4, Mui75 and all wiring exept elevator servo leads need to be placed in the nacelle or in the composite wing. That's a considerable amount of puzzling.
Full throttle f5d style cornering,5m diam loops and L-climbs are impressive for such a cheap airframe.
Worth copying

Erik,
I have some new 3.17mm adaptors that I asked Anthony to send me. I just ran a few on a motor. I didn't use a dial indicator, but they feel very smooth to the finger.

How about the 2950kv motor paired with CS10 fan, 110A ZTW esc running on 5s? Some people have even said this motor would be good on 5s and others are happy running it on 4s. Anyone have comments on this?

Some dealers list it at 2900 kv, others 2950, which is it?

Originally Posted by capt soap

Some dealers list it at 2900 kv, others 2950, which is it?

The Velocity-RC motor is 2900 kv. If the motor does not have a RED, Velocity-RC sticker on it, it's not a Velocty motor.

One dealer has the 2950kv motor listed with ARC as the mfgr. This is NOT true.