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Old 6th Dec 2018, 13:15
  #122 (permalink)  
Join Date: Apr 2014
Location: The Americas
Posts: 33
Grey horizons, glad you enjoyed. I always feel equally reassured when making consumer purchases with the Inspector #45 tag.

Pilots en mass around the world are finally getting their biggest wishes met with the advent of the ETR. They can live with the chronic lower back problems from the cruddy seating, if only the archaic driveshafts and gearboxes would disappear.

So...back to this locomotive.

We have got power to weight figures for electric motors being flung around the conversation with nary a mention of duty cycle, never mind record in service. Kinda of like sailors arguing where mean sea level sits in 100 foot seas....amusing but pointless.

Seeing as we are improving the type , I think it fair to ask the new ETR model to have the ability to hover at max continuous for prolonged periods. So using the aw169 as our testbed once again, this occurs at 1350 hp. So using 15% of Max continuous Q as being TR consumption again........ 200 hp.

Sure electronic motor controls have made leaps and bounds in the past couple decades. Complete control of the waveforms operating within the stators of a synchronous motor allowing near perfect efficiency of the principles of electromagnetic induction. Have the ground bound and efficiency obsessed , industrial process industries not innovated and taken advantage of this? Of course they have, sparing no amount of complexity in order to achieve efficiency of power. Lighting fast microprocessors paired with power transistors and resistors, all guided by millions of lines of possibly conflicted computer code.....what kind off fault or failure mode could possibly present itself? So much better than a clunky old driveshaft and gearbox, and there are no bearings to fail in an electric motor. Even If there were , you just use mag/lev tech.(Always use a [email protected] to do the same job a builders string has been doing for the past 10,000 yrs...so much cooler and its called "progress".)

After perfect efficiency has been obtained in controlling the repulsive electro magnetic forces between the rotor and stator where do you find your power density gains? Higher voltages through better cooling(.....like all the practical geometries haven't been tried yet) Insulation that doesn't melt or crack, and conductors that don't melt or heat up too much. I know that if we just stretch a little harder cold fusion , super conductors, super steel the weight of feathers are just around the bend....but in the meantime we are stuck with good old copper. Yes even consumer grade products like Tesla and Dyson. Though I feel we are on the cusp of a wave of stc's replacing the 1930's vintage, starter genies still on most helicopters with beer can size , LED backlit , hollow plastic ones accomplishing the same thing.

So we need an electric motor based on the best of industrially vetted technology to operate consistently at 200 hp to mirror our max continuous hover missions for SAR or aerial work. Doing a little window shopping I came up with this https://www.ziehl-abegg.com/us/en/pr...maxvent-owlet/. (Pg.44 of 66)

A drop in fenestron. Good looking, scimitar-scalloped blades , meets all the euro engineering approvals. 1.4 m diam. Bout right for the back end of a aw169. Power to weight for continuous duty? 50 hp at the svelte weight of 637 kg. Ahh but all that steel fat to be trimmed. Shes's gonna need some beefing up in the motor (4x 50) I think it's a fair trade off to add all that extra copper and substitute steel for aerospace material and call it even ~650 kg....she 'll taxi like a freight train because thats all She'll ever do.

I guess until the next invention comes along we are stuck with the practical limit of the electric motor being a quadcopter the size of most windscreens. Send me enough money and I'll build you one to ride in. You can't beat em join em.
Washeduprotorgypsy is offline