Hybrid Project - an alternative to starter/alternator combo.

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lelievre12

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So real life test. For car was trying to turn ac compressor with motorcycle stator as brushless motor. At 24v would only turn about 600rpm with no load. Had stator rewound and rpm increased with no load but once put under load rpm dropped and speed control shut off. This was an 80a speed controll. Stepped upto 60v and started to get rpm back. 72v even better. But basically saying even an ac compressor that takes about 1-3hp to drive wasnt possible.
The only working example of what you want to accomplish is a honda scooter that uses the stator as a starter and generator and the gm hybrids that use a rather large alternator with permanent magnets in the rotor belt driven.
The gm system is 48v and the honda system on scooter is 12v but has a boost converter built in.
Ive tested in real world conditions and its notpossible. You will more than likely find the same.
The gm hybrid alternator would be yourbest bet to start with. Especially cranking a diesel engine.
Well I never knew that. Of course GM have been making EXACTLY what I was intending all along.

1610067908627.png

Motor and Alternator all in one.

Thanks for this lead. I'll do some more reading about this option but looks exactly as I was intending.

1610068169163.png

Only 3KW continuous however I suspect the 5 minute limit may be much higher with temp monitored shutoff at 80C.
 

rv7charlie

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I just read an article interviewing one of the developers about the various implementations of this tech. If you want it, I'll try to dig up a link. The voltage is driven by Fed regulations on elaborate physical protections for higher voltage conductors. It said that one of the primary goals in the 42/48 volt systems was to allow a near drop-in mod to existing vehicles, which keeps development costs low.

Being honest about it, I have a hard time seeing any advantage to this particular tech in an a/c. Motor mode will only add ~4 HP to the engine's output; easily eaten by the battery weight.
 

Vigilant1

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Being honest about it, I have a hard time seeing any advantage to this particular tech in an a/c. Motor mode will only add ~4 HP to the engine's output; easily eaten by the battery weight.
Version 3 of GMs eAssist (on some 2016 Chevy Silverado, primarily in Calif) reportedly used an electric motor that provided up to 13 HP, but I don't think that changes the conclusion you reached-- a lot of weight and complexity for the intended benefits. I suppose if a battery with a sufficient C rate could be found so that a small battery could run the 13hp motor at full chat for 5-10 minutes, then a marginal safety case could be made for such a system-- in a plane where 13hp would make a meaningful difference in the ability to get to a safer landing/crashing spot.
But that's a lot of ifs, complexity, and cost.
 
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Jonny o

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OMG! That's exactly it! That dang thing will fly for sure!

Interestingly enough it looks like these fine folks are using an AC motor which has far lower starting torque than a BLDC. However to be fair, it doesnt look like that tractor has much compression left in it otherwise they wouldn't need the flaming torch!

The video just goes to show there is nothing new under the sun. Happy to see my idea is already proved!

That video was awesome. Definitely, made my day ! The torch has a lot of unburned, 300 degree, gaseous hydrocarbons coming off of it. PERFECT !

25 years ago, I was in Poland trying to purchase an AN-2. A mechanic started one that had trees growing around it that were 4 inches thick. Three months in Poland showed me how amazingly resourceful and sharp the people are.
 

DangerZone

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But prop calcs show similar results..
Every prop blade creates drag to produce thrust. Two blades of the larger prop might produce up to three times less drag than four smaller props. If drag is not added to your calcs, you might find out that reality does not care about computer calcs.
 

stanislavz

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I just read an article interviewing one of the developers about the various implementations of this tech. If you want it, I'll try to dig up a link. The voltage is driven by Fed regulations on elaborate physical protections for higher voltage conductors. It said that one of the primary goals in the 42/48 volt systems was to allow a near drop-in mod to existing vehicles, which keeps development costs low.

Being honest about it, I have a hard time seeing any advantage to this particular tech in an a/c. Motor mode will only add ~4 HP to the engine's output; easily eaten by the battery weight.
As i already posted this :


Motor is done from armature stolen from 1500 watt hub motor:


(he buy 3000 watt and split it in two, but armature is same)

And result was 15 kw motor with 3.5 kg weight.

Make four of them and you are in normal 2 seater power range.
 

stanislavz

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And one big plus for hybrid - if designed for passive cooling - it is able to give at least twice power for 30-60 seconds. Mostly limited to 5-6c discharge ratio of battery.
 

stanislavz

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For 4 vs one big prop - in rc time, i did used motolocal software. It was giving quite nice and steady results. Here is one of examples from similar, online tool Estimate Electric Motor and Prop Combo , twice diamter, twice pitch - 4 time power, 4 time thrust, similar efficiency.. :

1610109642706.png

1610109664769.png
 

Vigilant1

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Disk loading (engine power per unit of prop disk area) is often highly related to prop efficiency, esp at low airspeeds. If the installation allows for more total prop disk area for 4 x 10kw motors and 4 small props vs 1 x 40 kw motor and one large prop, I'd expect the small motors and prop to be more efficient, particularly at low airspeeds.
Static thrust can be a lot different than thrust at even moderate airspeeds (e.g climb speeds).
 

rv7charlie

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Stanislavz, my comment was in the context of a hybrid system. Even at 13 HP I have a hard time seeing its usefulness, except as an academic exercise on a *very* light a/c. Was that video just a taxi test? It didn't look like there was much danger of him getting airborne in the video.
 

stanislavz

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Stanislavz, my comment was in the context of a hybrid system. Even at 13 HP I have a hard time seeing its usefulness, except as an academic exercise on a *very* light a/c. Was that video just a taxi test? It didn't look like there was much danger of him getting airborne in the video.
He have more videos, with flyi ng. Just press at
 

henryk

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Emrax have similar ratio for continous power.
"EMRAX" =Synchronous AC permanent magnets e-mashine,

most anothers =Brush Less Direct Current mashines,=every time two phase active,
third is not working.

BTW=Yours opinion about Shkondin Motor/Generator phenomenon ???
 

stanislavz

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"EMRAX" =Synchronous AC permanent magnets e-mashine,

most anothers =Brush Less Direct Current mashines,=every time two phase active,
third is not working.
They all are same - permanent magnet brushless motor. Emrax is axial, other are radial. Different are only induction motors without magnets..
 

stanislavz

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BTW=Yours opinion about Shkondin Motor/Generator phenomenon ???
Unused rotor due to empty spaces in stator.

In my opinions each coil can reach it maximum tesla to provide max possible force. And each magnet have to see its coils. No coils for each magnet - less torque.
 

berridos

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Nice on hybrids is that engine havent got to be so reliable as there is some reserve power in the batteries for emergency landings. Maybe a two stroke driving the generator makes sense and one could save ice engine weight.
If i use a high reviving two stroke (located at the rear of the plane) to turn an emrax as a generator and the generated energy is used to turn a similar emrax at the prop, how much energy is lost in the process?
 
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