Testing Electric Propulsion Unit For a Light Airplane

KyleG said:
I'd be awfully surprised if the FAA relaxed fuel reserve regulations for electric aircraft. At least in Pipistrel's case, that advertised endurance includes a daytime VFR reserve.
Click to expand...

I agree.
And endurance is just the Operational side of it (FAR91), long after it's Certified.
Just getting Certified (FAR23) will be the tough part.
There are several Experimental planes flying on electrics - always have been for many decades. There are several companies actively and busily bilking naive investors into dropping huge sums on the promise of Certification. I know of one near Denver that's convinced some investors they'll have it wrapped up "soon". They don't stand a chance of being done in 5 years and a 300 million more dollars,. at least.
The failure modes ALONE, that have to be demonstrated to FAA witnesses, will be colossal. Every chip, resistor, cap, etc. Every MOSFET in the charging circuit. The boards, the solder. Every component; they all have to be shown what will happen when they fail, partially fail, intermittently fail, etc. And the software controlled charge/discharge? Every line of code has to be reviews and approved. Every winding on every pole of the motor.
You wonder why avionics are so incredibly expensive? You already know this, probably.
And after they do that, they have to show that every plane they build will be identical to the one they just held up as their prototype(s). That means every wire cut and terminated by a regulated and controlled process. That means every board wave-soldered in a controlled manner. That includes the exact windings on every pole of the aforementioned motor. Nope, can't just go buy that stuff unless THOSE guys can show the FAA they can make it exactly the same, too.
Now remember, we haven't even begun flight testing with extreme CG displacements (far beyond the Pilot Manual), spins, phugoid, etc.
This process prohibitively expensive to do on a "regular" small plane, with known components and known powerplants. Electrics? Enormous costs: which has been among the sticking points so far.

And just so there's no question. The Pipistrel isn't Certified, either.


Category: Experimental
 
wrat said:
Nope, can't just go buy that stuff unless THOSE guys can show the FAA they can make it exactly the same, too.
Click to expand...
Until the paperwork weighs as much as the plane, it isn't ready to fly.

I didn't just make that up. How much does regulation cost? Head over to Aircraft Spruce (they sell to airplane builders), and search for a battery. You'll find some examples of batteries that look like they're made the same day on the same assembly line, but one costs 2 to 3 times the other. These are bog standard lead acid batteries. 200yr old technology. Some lead dunked in sulfuric acid. But, one has certification paperwork, and the other doesn't.

And it isn't just the guy winding the motor that has to comply with regulations. He has to maintain the paperwork that the #10-32 screw that holds the motor cover is also certified. Can't use just any old screw.
 
wrat said:
And just so there's no question. The Pipistrel isn't Certified, either.


Category: Experimental
Click to expand...

Heh, glad someone else noticed that. It’s funny that the hold up that experimental exhibition ticket for one hull like it implies type certification.

That said, it looks like they have full-bore EASA certification, so US certification shouldn’t be too much of a stretch. I need to do some more reading; I’m not sure if it would come over under Part 23 or LSA.
 
Again, still not trying to rain on anyone's parade, but this is still a miss (on their part), not a hit.
KyleG said:
Heh, glad someone else noticed that. It’s funny that the hold up that experimental exhibition ticket for one hull like it implies type certification.

That said, it looks like they have full-bore EASA certification, so US certification shouldn’t be too much of a stretch. I need to do some more reading; I’m not sure if it would come over under Part 23 or LSA.
Click to expand...
LSA (Light Sport Aircraft) is a Special Certification within the Experimental Category that applies to the Operation of the aircraft. (yes, this is when it gets bureucratically bureaucratic for the sake of bureaucracy).
That is, if the aircraft can meet several greatly reduced (compromised?) rules of configuration (the way it's built) then it will be allowed to operate under several greatly reduced duties in the air. Many Experimental aircraft are basically 'factory built' in that they roll off an assembly line and command insane prices. That could not be done before LSA was passed as it had to be "homebuilt" or "amateur built" so they could only sell parts "not to exceed 49%". They can sell flyaway aircraft to be *operated* under LSA.
If you tell the FAA you want one of those and you operate it the way the FAA restricts, then you gotcha an LSA with far fewer hassles than a Part23 plane operating under Part 91 <whew>.
You can even build one, with some inspections, but you gotta build exactly to plans.
As I'm sure you know, among those restrictions are:
only 2 aboard
only 100hp (maybe a bit more?)
only daytime
take off and land from same airport (there's some debate on the "$100 hamburger" trip that seems to be allowed)
no controlled airspace
a couple of others....
In fact, if I stay *away* from LSA with my homebuilt, i can do much more than they, including anything anyone in a Cessna/Beech can do and at night and full IFR. LSA is a pigeon-hole of Operations, IMO, that works great for what it is: patch flying.
This is the "full-bore EASA certification" that they seem to have secured. Also allows for a company to sell these things as aircraft - which they couldn't do before.
But imagine a Kitfox as a Part23 bird. Or a Sonex (no chance, BTW). Or better yet, imagine the hoops they'd have to jump through. This is the very wide gulf between LSA and FAR23 Certified. Even the lowly Cessna 150 is Certified (which, irony of ironies, can be Operated under LSA, also).
So "shouldn't be too much of a stretch" is easily measured in hundreds of millions of dollars and years of insane, soul-sucking paperwork.
What seems to work thus far is to tell Investors that "we're very near" to get them to pump adequate funds into the company. Then live high-on-the-hog for however long, keeping the Investors reassured until they just walk away. Blame the whole failure on "that stupid FAA" which, in fairness, is every bit as motivated and efficient as the IRS. Seen it several times.
 
I haven't flown in a few years, but it appears you're mixing the LSA aircraft and sport-pilot things. LSA is a weight and power restriction, but if you have a PPL you can still fly at night (assuming your LSA has sufficient lighting), go to controlled towers, etc.

I built an RV-12 at one point (that was an E-LSA) and could do anything I wanted that any certified aircraft could.
 
I thought the rules were "be nice" and "no profanity"? Then you go and compare someone to the IRS! LOL.
Robert
 
wrat said:
What seems to work thus far is to tell Investors that "we're very near" to get them to pump adequate funds into the company. Then live high-on-the-hog for however long, keeping the Investors reassured until they just walk away.
Click to expand...

I think you woefully underestimate the effort these developers are putting into their airplane concepts. Telling investors that "we're very near" isn't nearly enough. You also have to generate some Hollywood worthy computer graphics. If you want more money, you'll need to generate an Xplane model and capture some videos of it virtually flying. To join the big leagues, you have to build a Boy Scout worthy remote controlled model, over-engine it, and show it flying.

I mean, let's give credit where credit is due. :)

I would like to see electric propulsion be a real thing, if only for ultralights. (a totally different category)
 
To put the FAA certification process in perspective, light aircraft are still commonly made such that the pilot manually controls the engine fuel/air mixture ratio. While this has some complications in conjunction with thinner air at higher altitude, and engine cooling at higher power, it is basically a certification issue. When’s the last time you saw a new car with a manual choke?

It does strike me as ironic that light aircraft are trapped by regulations to be archaic (avionics being a notable exception), while Boeing is essentially making planes like the 737max with systems so complex that pilots aren’t aware of these systems. But a major motivation for that whole debacle was avoiding the lengthy process of having the 737 max declared to be a “new” type of airplane rather than minor upgrades to the existing design. New airplane means more paperwork, more pilot training, more $.

In summary, the mountains of paperwork exist for real, valid reasons. But the mountains of paperwork don’t always mean those concerns are completely addressed, and they do impair progression on some things.
 
rabler said:
To put the FAA certification process in perspective, light aircraft are still commonly made such that the pilot manually controls the engine fuel/air mixture ratio. While this has some complications in conjunction with thinner air at higher altitude, and engine cooling at higher power, it is basically a certification issue. When’s the last time you saw a new car with a manual choke?

It does strike me as ironic that light aircraft are trapped by regulations to be archaic (avionics being a notable exception), while Boeing is essentially making planes like the 737max with systems so complex that pilots aren’t aware of these systems. But a major motivation for that whole debacle was avoiding the lengthy process of having the 737 max declared to be a “new” type of airplane rather than minor upgrades to the existing design. New airplane means more paperwork, more pilot training, more $.
Click to expand...
A big part of that is light-aircraft pilots themselves! We always say we would like new tech in the engines, but anytime someone comes out with fuel injection/etc, no one seems to buy them! At least some of the smaller planes are beginning to get some of the new features (The Rotax 912iS is a FI engine, and available in a certified aircraft).

At least the mixture in the Rotax aircraft was done automatically, I hated dealing with mixture by sound on the Cessna I flew.

EDIT: The rotaxes also didn't need a carb heat or choke knob, which was an awesome development! Having to only control throttle was a great relief for me.
 
I think the disrupting part has been the amateur built and maintained aircraft. New avionics were pouring in that rivaled what the big guys had. And wasn't tens of thousands for an AM transceiver. I think this started to become an embarrassment to the FAA, as it has clearly demonstrated just how big of a millstone poorly done regulation can be.
 
You must log in or register to reply here.
Back
Top