06-05-2017, 06:20 PM
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#61 (permalink)
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EcoModding Apprentice
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Flying stuff
Quote:
Originally Posted by sidecar
This seemed pretty open so:
The Flying Car
Almost all attempts Ive seen at this are rubbish. Actually all of them but Im prepared in the event someone comes up with a reasonable plan. After looking at lifting body aircraft in my University years, and in particular a soviet era ground effect machine VVA-14. Im convinced I have a workable formula. Its a 3 wheeler in the Morgan tradition, so as a motorcycle/sidecar in most regimes it avoids troublesome crash safety regulations (not that it wouldnt have any).
The mechanicals are as yet unsorted, but of course it needs a prop and a wheel drive driven from the same power source, just at different times. This isnt as complicated as it might seem, and could well plug in with this fora's bent on high fuel performance. But dont have any high speed expectations as its maximum weight is a demanding statistic!
#BabySteps
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I sure wish hydroplane designers would start with a stable ground-effect glider, and then add a water prop and rudder. Anything light and fast needs to be blowover-proof.
The biggest problem with roadable aircraft seems to be available lane width vs the wingspan needed for efficiency. Lifting bodies are nice and neat, but draggy without wing extensions.
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06-05-2017, 07:50 PM
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#62 (permalink)
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Master EcoModder
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What would I create?
I'd build a tilting reverse trike with driver in front of passenger, bucket seats, (similar to the Elio, but with a driver door on the left, and a passenger door further back on the right and a full body between the three wheels. Power would be battery driven front wheels (one electric motor for each, and the rear wheel would be the rear portion of a motorcycle with a small Atkinson cycle two cylinder engine replacing the motorcycle engine, which would be used for trips exceeding the battery's range.
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06-05-2017, 07:51 PM
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#63 (permalink)
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The body style would be sleeker, but the door treatment is illustrated in this video:
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06-05-2017, 08:57 PM
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#64 (permalink)
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Master EcoModder
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I for one would settle for an amphibian/submarine car.
B_Bob/elhigh — The lead picture in Permalink #51 is based on a spherical octahedron that has been prolated different amounts in different directions. IOW it's an asymmetrical zepplin. Consequently it can be scaled from belly tanker to motorhome size of variable fineness ratio. And it lends itself to formless construction.
here it is as a motor home:
With a lifting body and air-breathing plasma jets, it would fly.
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06-05-2017, 09:41 PM
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#65 (permalink)
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Solid Geometry
Quote:
Originally Posted by freebeard
I for one would settle for an amphibian/submarine car.
B_Bob/elhigh — The lead picture in Permalink #51 is based on a spherical octahedron that has been prolated different amounts in different directions. IOW it's an asymmetrical zepplin. Consequently it can be scaled from belly tanker to motorhome size of variable fineness ratio. And it lends itself to formless construction.
With a lifting body and air-breathing plasma jets, it would fly.
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Submarines are wonderful if you get caught out in a storm. Many boats could be saved if designed to sink 90% and stop.
I think that any simple, scanned shape has those same virtues.
It looks like a lifting body already, and as the old aircraft pioneers used to say, a tea tray will fly if you put enough horsepower into it.
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06-05-2017, 09:42 PM
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#66 (permalink)
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lead foot
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I have a Honda Insight powered by a non hybrid automatic. I would like to make it a hybrid once more and add in a rear electric drive that is adjustable and also plug it in. Have insane performance as well as a 80MPGe 75MPH commute. If (when) gas gets expensive again, its the direction I want to go.
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2001 Insight 11.5:1 K20a3 turbo / 04 Element
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06-05-2017, 11:17 PM
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#67 (permalink)
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Quote:
Originally Posted by Bicycle Bob
The biggest problem with roadable aircraft seems to be available lane width vs the wingspan needed for efficiency.
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I think the biggest problem is the average doofus is barely capable of managing operating a vehicle in two dimensions, let alone three. Imagine the carnage. Oh, that's right, everything will be autonomous (or government controlled) by then.
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06-05-2017, 11:26 PM
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#68 (permalink)
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The problem with the lead picture in permalink 51 is that Ackermann steering geometry requires one point in the back to triangulate from, and this photo shows two contact patch centers, putting the Ackermann point in front of one, and behind the other, creating scrubbing and side forces, one to the left, and one to the right. Why not mount the two rear wheels next to each other, side by side. The Ackerman point would then be between the two contact patches, and you would still have four wheels, with little scrubbing (none with freewheels or differential).
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06-05-2017, 11:54 PM
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#69 (permalink)
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Ackermann Approximate
Quote:
Originally Posted by Angel And The Wolf
The problem with the lead picture in permalink 51 is that Ackermann steering geometry requires one point in the back to triangulate from, and this photo shows two contact patch centers, putting the Ackermann point in front of one, and behind the other, creating scrubbing and side forces, one to the left, and one to the right. Why not mount the two rear wheels next to each other, side by side. The Ackerman point would then be between the two contact patches, and you would still have four wheels, with little scrubbing (none with freewheels or differential).
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Ackermann geometry is only close to correct, but at normal cornering speeds, the slip angles on the tires, differentially loaded as they are, produce greater errors and compensate for them all. Good steering geometry is good for handling, but only pushing a car around the shop really shows it at its best. Tandem or even triple rear axles with dual wheels to bear heavy loads on trucks do give a noticeable tendency to run straight, but are easily overcome by two steering wheels and the lever arm of a normal chassis.
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06-06-2017, 12:01 AM
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#70 (permalink)
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But do not two tires on the same real or virtual axle track a corner with less scrub than two tires mounted one in front of the other? The author of post 51 stated the fourth wheel was to qualify the car as a four wheel vehicle.
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