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Formula 1: Electric Version

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Grumpy Cynic
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(electric motors can be >>97% efficient, little to be gained there).
That's 97% of the power applied gets turned into work. The overall efficiency of the system might be improved?

I know most of the motor design theory says that copper wire is better than aluminum but those theories are dealing with ground based motors where size may be more critical than weight. Has anyone done any calculating or real world experimenting to see if the reduced weight of an aluminum wound motor in an aircraft is enough to offset its other disadvantages?
 

BJC

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Batteries are as petrol fuel a consumable. Electric batteries last a number of flights, the petrol in the tank last one flight…
To keep cost down and make the race closer and more entertaining, rules that restrict batteries to one type cell make sense. A discharge rate limiter is a mean to make the battery pack last a little longer.
The more rules, the less innovation in the formative years. And without innovation, electric powered racing likely never will evolve into a viable sport. If I were trying to start electric racing, I would probably have a minimum weight and a minimum wing area along the lines of the VW class (as per Raceair's suggestion) and require that the racers taxi to the pits under their own power after the race. Then, with the experience of some successful entrants, I would begin a slow evolution of rules to make the racing competitive, but not so much as to stiffle innovation.


BJC
 

bmcj

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Two points in opposition...

1. Batteries want to blow up when drained too fast.

2. Racers want to drain the batteries faster to get more speed.

It definitely wouldn't be a boring race for the spectators.
 

BJC

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Two points in opposition...

1. Batteries want to blow up when drained too fast.

2. Racers want to drain the batteries faster to get more speed.

It definitely wouldn't be a boring race for the spectators.
In opposition to what? Merlins and Griffons blow up too when run at too high a power. We are talking racing.


BJC
 

wwalton

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I like the idea that you could burn up your power plant if you don't regulate it. It adds to the excitement however I have a feeling that the Feds may not see it that way.
Part of this will obviously be a chess match within a sprint race. I don't see a lot of failures of the current formula 1 engines at least not in battle. If the rules were left open and each team had to decide how much risk to their power system they want to take, then you could see jack rabbit starts and last lap runners.
The IF1 gold was like that Knotty Girl was like a drag racer but the others caught and passed in a few laps.
 

Riggerrob

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Lots of good ideas in this thread ...... but let's not narrow the field too early.
We should be discussing a series of classes with slowly evolving standards.

As the OP suggested, the first generation should operate under existing Reno Formula One standards. Airframes would conform to current F1 standards with only firewall-forward modifications to accept electric motors.
To attract sponsors, pit motor manufacturers against each other.
For example, start the week with a series "Toyota Prius" class elimination heats. Competitors would be limited to factory-stock Prius motors only containing Toyota factory parts. The only variations allowed would be in choice of propellers, throttle mechanisms and batteries. Towards the end of the week, the top five Prius racers would compete against the best from the Tesla class. Then the best from those elimination races would compete against the best five Chevy Volt racers. By the end of the week, spectators could easily see who built the best electric motors.
Win on Sunday, sell on Monday.

This would also see Sensenich propellers competing against MT propellers.

To keep everyone on a level-playing-field, insist on competitors arriving in the pits 3 hours before start, with dead batteries. Judges would monitor each competitor up-loading "X" number of kilo-volts. After landing, judges would confirm minimum remaining kilo-volts to discourage competitors from landing with zero fuel reserves.

Alternately, battery manufacturers could sponsor races by providing identical, fresh batteries at the start of each race. Eventually Siemens would compete against Every-Ready against Ray O Vac, etc.

Stick with Formula 1E rules for the first few years, but then start giving 3 years warning for rule changes. Three years' warning would give teams enough time to adapt their planes to new rules, with few surprises.

E racers could learn a bunch of marketing lessons from the Red Bull Air Racers.

Eventually we would see an Unlimited E class. The first difference - from current Reno unlimited rules - would eliminate minimum empty weight rules to allow Glasairs, Lancairs, RVs, etc. to compete.

A smart marketeer could also hold the crowds' interest during the ferry phase (between races in different cities) by broadcasting video from a variety of angles. Cross-country competitors would need to conform to FAA fuel reserve regulations - by demonstrating reserve battery power - with zoom climbs over the destination airport.
 

tspear

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Over thinking it. Provide the batter spec in terms of cell tech, and capacity.
If you want to run close to spectators on a small course, require a max stall speed, weight and some type of drag chute which can be remotely released by the refs in case they feel the pilot is out of control.
In the rules, provide for changes/updates to the battery spec every two or three years.

From a practical perspective, limiting the battery is like limiting the engine in the current F1. If you want Tesla to sponsor it, let them pick the battery pack and provide it. They can then announce what the battery will be a year in advance.

Tim
 

Hephaestus

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Wouldn't a minimum weight make more sense than maximum? >500lbs with pilot makes more sense to my brain than <800lbs.

If you want to carry some extra weight to fight the wind - have at er, you've still only got 9999aH of battery power, you'll need to accelerate that extra weight, and get it off the ground, and around the course for x # of laps... Also saves on the race to unobtanium materials if a decent prize purse appeared...
 

tspear

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Wouldn't a minimum weight make more sense than maximum? >500lbs with pilot makes more sense to my brain than <800lbs.

If you want to carry some extra weight to fight the wind - have at er, you've still only got 9999aH of battery power, you'll need to accelerate that extra weight, and get it off the ground, and around the course for x # of laps... Also saves on the race to unobtanium materials if a decent prize purse appeared...
Max/min weight is because of possible wake issues. If this is a tight course with spectators near by, and multiple planes flying you need to minimize turbulence differences.
If you stay with the larger Reno course, you can just do the battery pack and let everything else sort itself out.

Tim
 

bmcj

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In opposition to what? Merlins and Griffons blow up too when run at too high a power. We are talking racing.


BJC
I meant that my two points were in opposition to each other, but you probably knew that already. Your point is a good one.
 
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pictsidhe

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Simplest, specify max weight.
If you want to limit cost and prevent it being a wallet race, specify the type and max number of cells. a max weight won't be needed then. Eg. A123 cells aren't too hideous in price, have a high drain rate and are pretty safe. They are kinda small, though. There are others. Perhaps Mr Musk would be so kind as to provide discount cells?
If you race a certain time, the drain rate is predetermined and can be matched to specified cells. Going flat out 3/4 race and coasting the remainder is not efficient. Competitors will know that.
If EF1 takes off, maybe have an unlimited class.
 

autoreply

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Everybody is missing the most important point.... an electric air race would bring in more and bigger sponsors, the E-car companies would use it as tech demo and development the same way they use / used car racing to develop better IC engine technology.

Electric air racers would have the "clean sheet" advantage of writing the rules in usch a way as to create racing around a smaller course, so that air racing can be safely brought to smaller airports, meaning that a larger number of races would happen... meaning that the sponsors would get more public exposure... meaning that the whole thing would be more worthwhile for them to sponsor.

Electric racers could likely be built smaller and lighter than IF1, which means that having them race around a 1.5 or 2 mile oval at 140mph would stilll create the appearance of high speeds and excitement (like old-school dirt track car racing).


The technical details of how much battery weight, and how much voltage or current, are unimportant. Those rules will be figured out to balance safety (for both the crowd and the pilot), entry cost, speed, etc.

I'm thinking something the size of a Cri-Cri, Davis DA-11, or a Jeanie's Teenie, but sleek and laminar.
Why bother accepting things less exciting than today? If we copy F1 one to one, standardise the batteries (amount, type, max discharge level), you can race next year.

All the ideas about new, separate classes, sponsorships etc are nice, but the world solar challenge or formula student didn't start out with very elaborate systems either. By fitting it in directly with F1, it can organically grow. Heck, plenty of competitions (sailplanes) where different classes race the same course, but are scored in their respective classes. Then you don't even need 8 electric racers to start with.

That's 97% of the power applied gets turned into work. The overall efficiency of the system might be improved?

I know most of the motor design theory says that copper wire is better than aluminum but those theories are dealing with ground based motors where size may be more critical than weight. Has anyone done any calculating or real world experimenting to see if the reduced weight of an aluminum wound motor in an aircraft is enough to offset its other disadvantages?
The solar power guys do up to 99% efficiency I think. What I meant was that even if you optimize those last 3% for perfect efficiency, you've only gained 1% in speed.

If you look at today's F1 racers, I think a 50% drag reduction is possible. That's where the big gains are and they require very little money, just labour and knowledge.
 

Victor Bravo

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Since the performance of the airplane largely depends on power to weight ratio, as you increase the takeoff weight of the airplane you increase the power required, and thus the battery storage... but I believe the performance suffers more/worse/faster the heavier you get.

The proof of this is in the R/C model world. With small, light R/C models the electric airplanes are faster and perform better than the IC models. However, as you move up to man-carrying aircraft size, the electric versions are slower and require more efficient airframes than the equivalent airplanes with IC engines. This is because the advantage of electric does not yet "scale up". I believe this has been discussed many times on HBA.

I believe the same comparison can be made with model "slot cars" and full scale IC dragsters. I understand that the proportional acceleration and speeds are much greater for the small palm size slot cars than the big fire breathing funny cars.

So IMHO the only way you can create a fast, exciting, maneuverable electric racer is to make it as small and light as possible. If you force the electric racers to be the same size/weight/area as a Cassutt or other IF1 racer, the powerplant and batteries will be proportionately heavier and "clunkier". Granted, aerodynamics get a little better as the Reynolds numbers go up, but I believe that the percentage of aircraft weight is larger on a large aircraft than it would be on a small aircraft to achieve the same acceleration/speed/range.
 

Swampyankee

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Wouldn't a minimum weight make more sense than maximum? >500lbs with pilot makes more sense to my brain than <800lbs.

If you want to carry some extra weight to fight the wind - have at er, you've still only got 9999aH of battery power, you'll need to accelerate that extra weight, and get it off the ground, and around the course for x # of laps... Also saves on the race to unobtanium materials if a decent prize purse appeared...
My reasoning for both a minimum and maximum weight was to use it as an indirect way of limiting battery weight, as I was thinking mandating a specific motor and perhaps a specific controller would permit more freedom in the design of the aircraft. As for noise, I think a close race where the all spectators can see most of the course is more important for excitemenr than noise. Something like an offshore powerboat race or high-end rally has the noise but the spectators can't see much of the race; this would bore me, at least.
 

autoreply

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Since the performance of the airplane largely depends on power to weight ratio, as you increase the takeoff weight of the airplane you increase the power required, and thus the battery storage... but I believe the performance suffers more/worse/faster the heavier you get.

Speed will scale with power over drag cubed, irrespective of the size. With a human on board, minimum drag is roughly fixed.
For these short races, climb isn't much of a consideration. If it is, a given percentage of a given electric battery will give you the same amount of altitude gain, irrespective of the size of the airframe. It's just that model airplanes tend to fly pretty low.
Modern batteries have a specific height of about 20 km with all the airframe inefficiencies factored in, assuming a low-drag climb (sailplane, high AR). So 50% battery mass system @TO will allow you to climb to about 10 km before the battery is exhausted.

The proof of this is in the R/C model world. With small, light R/C models the electric airplanes are faster and perform better than the IC models. However, as you move up to man-carrying aircraft size, the electric versions are slower and require more efficient airframes than the equivalent airplanes with IC engines. This is because the advantage of electric does not yet "scale up". I believe this has been discussed many times on HBA.
There is no fundamental difference between the two.

Batteries have an order and a half lower energy density. Electric has 5-10 times the power density. The Siemens-powered Extra is a good example; the same insane power density as an RC plane, but an endurance of a couple dozen minutes at most, RC-style.

That's one of the disadvantages of constraining MTOW. If you allow say 500 lbs empty weight, someone can be tempted to put in about 300 lbs of batteries. That's an average of 270 HP for 8 minutes...

Bottomline; electric is great for high power, but horrible at packing a lot of energy. Great for short races, awful for long-distance applications, whether it's RC, car, ships or air racing.
 

autoreply

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In a closed circuit race in front of spectators, induced drag is the dominant drag for the airframe, just as it is when climbing.
If that's the case, you're doing it wrong.

Best glide for a Cassutt with almost square wings is what, 100 mph?
Have a look at the graph. Speed, induced drag as a percentage of original drag, frontal drag as a percentage of original drag and total drag relative to the drag at 100 mph:

"@1G"
V Di Df Dtotal
100 50% 50% 100%
125 40% 78% 118%
150 33% 113% 146%
175 29% 153% 182%
200 25% 200% 225%
225 22% 253% 275%
250 20% 313% 333%
275 18% 378% 396%
300 17% 450% 467%



So what about 4G's continously?
"@4G"
V Di Df Dtotal
100 200% 50% 250%
125 160% 78% 238%
150 133% 113% 246%
175 114% 153% 267%
200 100% 200% 300%
225 89% 253% 342%
250 80% 313% 393%
275 73% 378% 451%
300 67% 450% 517%


Even at 4G's and going 250 mph, induced drag with a short-winged Cassutt is only 20% of the total drag. In reality less (cooling drag, and absolutely nobody is flying an average of 4G's with a short-winged Cassutt).

For a realistic case, maybe 10% of the total drag for a silver class winner?

The bigger factor is the airfoils higher-aspect ratio wings allow. Laminar flow is pretty dependent on your Re range.
 

Riggerrob

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..........

That's one of the disadvantages of constraining MTOW. If you allow say 500 lbs empty weight, someone can be tempted to put in about 300 lbs of batteries. That's an average of 270 HP for 8 minutes...
..........
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Original Formula One rules specified a minimum weight to ensure strong airframes ...... airframes strong enough to handle the turbulence and G-forces encountered during low-altitude air-races.
Any new set of EF1 rules needs to start with minimum airframe weights ..... then add battery weight. If you can convince RayOVac to sponsor air-races, then every competitor starts with the same RayOVac model 123.... battery pack.

Reiterating the OP's suggestion ..... if we start with Formula One rules, then we have known airframes available to race NEXT YEAR. Sponsors have very short attention spans.

If you want a more efficient class - to maximize the advantages of electric motors - then announce new class rules to take effect 3 years in the future. Three years is enough time for teams to enlist sponsors, engineers, fabricators, pilots, etc. and run a few test races before the new class rules come into effect.

Those new class rules should also in "sunset clauses" that require re-newing class rules after 6 .... 9 ...... 12 ..... 15 years. Regular rule changes prevent any single team from dominating, encourage innovation and maintain spectator interest.
 

TFF

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Does anyone know how they managed the Siemens Extra's battery? Did they reuse the same battery for each record or did they burn it up and changed to a new pack for the next?
 
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