| Author | Message | ||
     Gregtonn |
I for one would have said this technology was years off: https://www.eviation.co/alice/ http://chamberbusinessnews.com/2018/08/23/israeli- electric-airplane-startup-eviation-lands-in-presco tt/ Ironic that they are setting up shop a few miles away from me. I will be visiting. G | ||
| Aesquire |
I considered electric but the range is very low and the cost is double. It is a viable option for motor glider types, where you use power to takeoff and climb, typically to 3000 feet of so, then shut down and try to soar. Flip the power back on to slide home when the lift dies, or climb back up to try again. The sticking point, is battery storage density. Today, you can fly around the local area, but not cross country. In a typical light Cessna type plane, but for a lot more money. Even with $6 gallon fuel, the payback on electric is after you're dead, and you will be able to fly from NYC to LA about as fast as the Vin Fiz! https://en.m.wikipedia.org/wiki/Vin_Fiz_Flyer Yeah, I have a brain full of this kind of thing. Alice looks pretty. Is there any real hardware? All I've seen is cgi dreams. There's a LOT of people with slick websites, pretty pictures of pretend airplanes flying in exotic locals, and butt tons of money going, somewhere. There's even a few actual aircraft. Black fly is flying! So here's a few buzzwords to watch for. Flying car! We've had flying cars since the 1930's. A few have had production runs as high as Three! This seems to be the closest to actual sales. https://www.pal-v.com You should notice it's not a car. But legal on road in Europe! It's a tilting trike, and I'd love one. It flies fine. But you need a hard to get gyro licence, hard to get because of few instructors, not difficult to fly. Or a gyro add on to your Private (normal) plane licence. ( how it's usually done ) You also need an add on rating for tail wheels, and flying boats/float planes. So it's not impossible to get trained & legal, it just takes time and money. (Partly because of hotel rooms for a week or more 8 states away while you take classes & fly 5-7 days a week ) Plus, the spa you send the SO to in return. Electric airplanes! They are real! But you are more probably looking at a scam. 650 miles with 7 passengers is going to happen! But not this day. Maybe soon. But not that I can afford. But to be fair, I'm having to budget an engine vs. a new roof, so I can't afford anything! But I will by golly be flying this year, if only as a student to punch the legal holes in my ratings. Local instructor, "How the heck do you have all this Citabria time without a tail wheel rating?" Well, they didn't have them, then. " Citabria, Mooney, Beech, DeHaviland? Douglas! Wtf? Wright 1903 Glider???? " Yeah, my log book looks odd. | ||
| Gregtonn |
As I said it's here, more precisely 13.6 miles from my present location. I also said I would have thought the technology is years from being useful. I am in a position to do some investigation and will be doing so. G | ||
| Aesquire |
Oh, please let us know. It wouldn't be the first time I thought some thing was a scam and it turned out to be a world beater. There are several soon to fly ( hopefully ) projects I know using Zero motorcycle engines. With aviation, it's 90% done, 90% to go. NASA is doing work on multi motor/fan aircraft. It's a big advantage of electric, that you can put a prop and provide thrust where you want to, instead of where you can get a heavy driveshaft or massive engine. That it's also a cheat to use small, light motors instead of non-existent large, light motors, is kinda a bonus. OTOH, I've been right about Facebook. | ||
| Sifo |
A couple of things... First, the specs say "Range + IFR reserve 650 miles". What does that make the range of a flight plan? Perhaps Patrick can fill that in. It appears to be aimed at competing with prop or turbo-prop charter aircraft. These typically need to turn around fairly quickly, i.e. an executive tells the pilot, be ready to take off as soon as my business here is done. So... I don't see any details on "refuel" time. That's critical to being viable. Do you need an airport that has specialized charging stations? Being able to simply plug into any 220 outlet implies a good amount of weight onboard for charging equipment. Not a great thing. Even worse would be trying to use it for scheduled routes. You need to get the plane turned around as fast as possible and on it's way. Sitting idle while recharging is going to cost a lot of money. Is the corporate guy who's looking to by a private airplane for his business travel going to consider this? I doubt it. Again, it's about the turn around time. They need to land, get their business done, and get on the move again. I see dismal sales in their future. Look them up in two years and see if they are still making anything. | ||
| Teeps |
Looks good on paper... or the computer monitor. I'll believe it when I see a production unit for sale. location location location is to real estate as weight weight weight is to flight. | ||
| Gregtonn |
location location location is to real estate as weight weight weight is to flight. Actually, whether or not you know it, you stumbled onto something there. One advantage of the way Alice is built is that the multiple power cells can be located most effectively for balance and stability. Also there is no change in flight characteristics due to fuel movement or burn off. G | ||
| Aesquire |
The downside of that is it doesn't lose weight as fuel burns off. Otoh, that does make the math easier.  | ||
| Pwnzor |
I'm wondering if, as in Tom's scenario, a business person who makes regular back-and-forth flights could just have battery packs at either end of his route to be swapped out...? | ||
| Sifo |
I'm wondering if, as in Tom's scenario, a business person who makes regular back-and-forth flights could just have battery packs at either end of his route to be swapped out...? Interesting thought, but it's probably a very small portion of potential business airplane owners who would be doing fairly short hops to the same location all the time. Being a 9 passenger airplane tends to take it out of that category too. No doubt it's a niche, but a tough one to build an expensive business on. I'm still wondering what the real world range of "Range + IFR reserve 650 miles" means. http://www.aviationdictionary.org/NBAA_IFR_Fuel_Re serves Given that definition, the realistic range may not be all that far. I may be misunderstanding their meaning of how they represent the range though. But it it's 650 miles minus 200 miles, minus fuel needed for holding 30 minutes, minus fuel needed for a climb out, the range might be surprisingly short. | ||
| Gregtonn |
The downside of that is it doesn't lose weight as fuel burns off. That's actually the downside of fueling an IC engine. Burning off fuel does nothing to add to the payload. (You are already in the air). It does however require more thrust to launch that fuel on takeoff. See how that works?  G | ||
| Aesquire |
Energy burn during climb is much higher, can be more than double, than cruise. Hold flight is typically slower & less fuel/battery use than cruise. That is very airplane dependent. A fast turboprop circles the pattern near idle power, while a Cub is at cruise or full speed. The turboprop also burns lots of fuel at idle, and huge amounts at speed at low altitude, so calculating range is complex and they use computers or slide rules, plus an airplane specific algorithm. ( spread sheet, or fill in the blank paper form ) There's a reason that aviation requires classroom work. Any idiot can fly an airplane, I'm proof of that. Doesn't even take skateboard level athleticism. Decent automobile level will do. ( albeit in more dimensions ) You need math to do anything cross country so you don't run out of fuel. Or fly the wrong way. ( like over the live fire artillery range ) | ||
| Ourdee |
Any idiot can fly an airplane A cropduster let me fly his plane when I was 12 or 13. That is the easy part. I wasn't interested enough to become legal. | ||
| Gregtonn |
Energy burn during climb is much higher, can be more than double, than cruise. Which is when the fuel load for an IC engine is at its greatest. See my statement above. While I never did get my pilots license for financial reasons, I did take the required ground school courses. I am well aware of and able to do the math. Heck, I can even do the math required to design satellites. G | ||
| Sifo |
That's actually the downside of fueling an IC engine. Burning off fuel does nothing to add to the payload. (You are already in the air). It does add to the efficiency in flight though. You never get that weight reduction from batteries. That's only one of their downsides. Also if you have to do a go around at your destination, with a battery airplane, you will be climbing out at full weight, not at a reduced weight. That means a lot to your "fuel" consumption when you are already low on fuel. It also means you always land at full weight. Not beneficial by any means. Some larger airplanes may have to dump fuel if they have to return to the original airport to reduce weight. A similar design with electric (assuming it were possible) would have to reduce the weight to the maximum landing weight, not the maximum takeoff weight. | ||
| Airbozo |
Any idiot can fly an airplane Too True. I have almost 100 hours on an MD11 simulator and about 60 on the C17 simulator. Taking off was a little more difficult than maintaining a steady course, but it took me well over 100 tries before I could ever land that MD11 without any alarms going off (meaning loss of life or cargo). Never achieved a "qualified" landing in the C17 simulator. Take offs were a blast. One thing that took the longest to get that MD11 in the air was the fuel management system. As the fuel was consumed, pumps moved the fuel around the plane to achieve optimal weight distribution for maximum fuel efficiency. | ||
| Darth_villar |
IC airplanes are not required to take off at full fuel load. This means you can increase payload depending on estimated flight time / distance. Electric airplanes cannot benefit from this unless they had some type of modular battery system that allowed removal of unnecessary cells. Personally, I'm just looking forward to multistage low output (sub 500 HP) turboprop engines. | ||
| Sifo |
Electric airplanes cannot benefit from this unless they had some type of modular battery system that allowed removal of unnecessary cells. Just spitballing a couple of ideas here. Decide for yourselves which one is the worst... 1) A battery system dedicated to initial takeoff and climb, that then detaches and flies back to the originating airport as an autonomous drone. 2) JATO rockets!  | ||
| Gregtonn |
I for one would have said this technology was years off... This was intended as an FYI thread not an endorsement. Alice may fly at the Paris air show in June, or not. So far the Prescott Headquarters is an empty building with a logo and name on it. G | ||
| Aesquire |
So you want me to not only compete with Cessnas for a spot to land, but now robot battery packs? I fly gliders! You Pretty much have limited options on when you land, and can't go around. ( it does concentrate your attention when there's no motor to save your sorry butt from misjudgment ) | ||
| Sifo |
I'll take that as a vote for JATO rockets! | ||
| Aesquire |
Gregtonn, I did catch your skepticism. I was surprised by Black fly. There's multiple human food processor multi copter man carrying drone flying motorcycles out there. A few I've seen actually fly a few feet up. One backyard mechanic model, not a megacorp or pretty brochure go fund me scam, has actually flown a few miles cross country to pick up a drink at a local convenience store, & return. He only goes ten feet up or so because he's not stupid and only moderately crazy. ( you wouldn't fly high on it either ) Black fly, otoh, looks reasonable, has proven transition from vtol to normal flight. ( very very difficult, and many can't, including major projects from Curtis, Lockheed, & other Aerospace companies ) Solving the landing vs. flying cockpit visibility issue by just ignoring it and using an auto land system is brilliant. In landing mode, the pilot has zero forward visibility, so.... Just push the button to hover, look over your shoulder to be sure you're not over a building, and push the "land" button. Gravel, grass, a pond, no matter. However, to save weight, it doesn't taxi. No fancy landing gear. Just a floating carbon fiber pod. | ||
| Gregtonn |
Bump | ||
| Froggy |
Moderator bump out of the archive | ||
| Ourdee |
I vote for a steam catapult. Or ground based winch and tow rope/dyneema line. | ||
| Two_seasons |
Vin fiz is lighter than most Harleys | ||
| Pwnzor |
JATO That is all. | ||
| Aesquire |
I will comment that Alice is taking advantage of a few facts of electric power that seldom are noticed in cars and trucks. The motors are lighter than IC engines of the same power. Thus you can hang them in the tail and other places with less restrictions that IC engines. Note that overall weight is higher, by a Lot, for the same range because the batteries are less energy dense than kerosene. But lighter & physically smaller motors give great flexibility in where to stick propellers, and less drag from the nacelle the motor is in. Less cooling drag, too. ( a major source of drag in IC power ) Remember that normal airplanes with a wing, fuselage, & tail, are balanced like a teeter totter around the fulcrum of the lifting wing. ( at It's center of lift. ) The weight is slightly ahead of the fulcrum, and the tail pushes down to balance. ( canards & tandem wings are different ) While this reduces efficiency, it provides a natural stability. The weight doesn't change, while the down force on the tail varies with airspeed. Thus, as you speed up, the tail forces the nose higher, slowing you back down. Slow down, the tail down force lessens, the nose drops, and you speed back up. Simple, elegant, no computer needed. Because IC engines are such a large percentage of weight in a small plane ( Alice isn't that big ) that restricts where you can put them. The load you carry, passengers or freight, is distributed around the center of gravity. As is fuel. You do that so changing weight doesn't ruin that teeter totter balance. You just can't put everything in the middle. And, with rare exceptions, long drive shafts to remote the propeller from the engine give you serious vibration issues. And always more weight and complexity. Thus the engine has the propeller on the end of the crank, plus a short extension, and the prop has to either blow around the body of the nacelle or fuselage holding the engine, if a tractor design, or suck air from around it if a pusher. In both cases airflow is blocked and efficiency reduced. Smaller motors improve that. In nearly every case, you get some advantage from a smaller, lighter prop turning gizmo. And the greatest advantage is flexibility to locate the props. Also, from a history perspective, it's ironic/funny to me that Alice is a tri-motor. The Fokker, Ford, and Junkers most successful transport planes were all trimotors. Admittedly, 1920s & 30s designs. File that in the "nothing new under the Sun" folder.  | ||
| Sifo |
All of that about the nacelle disturbing the flow through the propellers is certainly true and hurts efficiency. It's not nearly as bad as most people would expect though. The simple fact is that the farther out you go on the prop diameter, the more efficient the prop. Add to that, the area of prop wash is dramatically larger in the outer half of the diameter than the inner half of the diameter. In short, the inner part of the prop doesn't do that much work. Numerous reasons for this, from operating at a far from optimal pitch, relatively slow speed, and poor airfoil, just because it needs enough bulk to keep the rest of the prop from flying off into parts unknown. All of this lead some model airplanes designed for speed to use a single bladed prop. It lets you use a bigger diameter prop on the engine size you are allowed in the class. It doesn't scale up well though because the required landing gear gets way too tall.  | ||
| Aesquire |
Prop size is also limited by tip speed. Once the tips go over Mach .7 efficiency drops off like a rock and power converts to noise, not thrust. That's why light plane Lycoming style engines since WW2 are low RPM ( 2200-2700 ) & direct drive at crank speed. That fits a typical light plane prop. To get more power for displacement, you need a gear box to spin the engine faster, & keep the prop slow enough. The big engines in WW2 planes have geared props, as do the tiny ones used in ultralights. ( which may use belt drives ) Yes, there have been experiments with supersonic propellers, but noise issues made most people give up on the idea. The Republic Thunderscreech infamously caused nausea and severe gastric disturbance with ground crew at over 100 yards. With headsets. |
