Cargo plane approach to the flying car

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by cluttonfred, Mar 8, 2013.

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  1. Mar 27, 2019 #101

    Aesquire

    Aesquire

    Aesquire

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    The "automobile" as legally defined in the U. S. and U.K. Is going to be a heavy load because of crash & safety regs.

    I'll point out in England, the 3 wheeled vehicles evolved to avoid automobile taxes and regulations. From the iconic Morgan to basically road going wheel chairs for the many Veterans, there was a wide range of "things" on the road there when I was younger.

    in the U.S. the cost to make a light weight Mini Cooper that is road legal is way too high. But a scooter with a sidecar is not. The difference between scooter & motorcycle is mostly speed.

    for stability, the "tadpole" trike arrangement, like a Can Am Spyder https://en.m.wikipedia.org/wiki/BRP_Can-Am_Spyder_Roadster is a good choice.

    Better/lighter/cheaper is... https://ultimatemotorcycling.com/2018/09/23/2019-can-am-ryker-review-20-fast-facts/

    Or you can design your own..... Here is state of the art. ;)



    Or maybe something slower?
     
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  2. Mar 27, 2019 #102

    cluttonfred

    cluttonfred

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    As in many things, the answer in the USA is "check your state and local regulations." That said, there are less restrictive categories for three-wheelers in the USA and there is also a Federally-recognized category for low-speed vehicles or neighborhood electric vehicles (basically electric golf carts and the like) that could be used here if you're not in a hurry. Additional safety requirements kick in above 25 mph top speed.
     
  3. Mar 27, 2019 #103

    Victor Bravo

    Victor Bravo

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    I believe there is also a "special construction" vehicle category in the US, which I believe includes homebuilt and one-off cars, those big motorcycle based trikes with VW rear axles, the strange electric and solar prototype college projects, Popular Mechanics kit cars, etc. etc.

    What this means is that if someone built a cargo-plane mothership to carry around a three or four wheel fabric covered homebuilt lightweight minimalist car... and that car was NOT being mass produced and offered at your local dealership... the majority of the problem goes away.
     
  4. Mar 27, 2019 #104

    Riggerrob

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    .............................................................:...
    May I please have a Danish Army side-car, circa 1939, with the 20 mm anti-tank gun?
    Hah!
    Hah!
     
  5. Mar 27, 2019 #105

    Hot Wings

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    Production in any quantity puts it under DOT and EPA jurisdiction. However the DOT and EPA, as far as I know, still don't have the equivalent of the 51% rule for kit cars.

    1. The production, sale and importation of automotive bodies alone (i.e., no chassis, engine or transmission) are not regulated by EPA since such units are not considered "motor vehicles" under the Clean Air Act. EPA form 3520-1 is not required for imported automotive bodies. A motor vehicle from which the engine has been removed is still a motor vehicle and is not considered a body.
    2. The production, sale and importation of vehicle parts (engines, transmissions, chassis, vehicle bodies, etc.) are not regulated by EPA because parts are not considered motor vehicles under the Clean Air Act. However if the parts constitute a disassembled vehicle or an approximate disassembled vehicle, the combination is considered a motor vehicle under the Clean Air Act. Any attempt to use this policy to circumvent the Clean Air Act or the Imports regulations will be considered a violation of the Clean Air Act and will be strictly enforced. An example of such circumvention is:
      • A kit car maker who also provides the engine and transmission before or after production/importation of the body/chassis.
     
  6. Mar 27, 2019 #106

    Tiger Tim

    Tiger Tim

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    Doesn't someone make a belly pod for the RV-7 that holds some sort of collapsible motorcycle? Or find a Honda Motocopmpo and carry it in... nearly anything!
    [​IMG]

    Some clever individual could remake something like that Motocompo but with electric power (and a sweet stereo!) and then presumably take over the world. Well, the urban parts of the world, at least. Make it so you can pull it like rolling luggage once folded and pull it right up into your office or meeting place to be stacked in the corner with the rest of them all day. Maybe more of a project for the forum at homebuiltminifoldingmotorscooters.com but still a little relevant to this discussion.
     
  7. Mar 27, 2019 #107

    N15KS

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    We make the belly pods and 225cc motorcycles for the RV-10. They're also flying experimentally on the Cirrus SR-22. We also designed an internal motorcycle loading system for the Piper PA-32 and PA-34 airplanes. They work very well and door-to-door transportation is a game-changer.

    I have some other concepts that I'd like to explore, but there just isn't much money to be made in personal aviation. For now, I'm focused on our more lucrative consumer products.


    [​IMG]
    [​IMG]
    [​IMG]
     
  8. Mar 28, 2019 #108

    Tiger Tim

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    Ah yes, that’s the one. For some reason I was picturing it on a smaller RV. Neat setup, does it take very long or make much mess of your clothes to pack and unpack the bike?
     
  9. Mar 28, 2019 #109

    N15KS

    N15KS

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    It takes me around 120 seconds from sitting in the cockpit to sitting on a running motorcycle; a little faster if I rush. Tying down the airplane often takes longer. Here's a pretty good demo:

    There's no mess as the motorcycle is extensively modified. For example, the carburetor drains into a catch can (model airplane fuel tank!), along with a few drops that escape past a breather valve installed on the motorcycle fuel tank. At the push of a button, a 12V pump returns the fuel to the main tank. There's no need to drain or touch gas or oil.
     
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  10. Mar 28, 2019 #110

    Sockmonkey

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    I think you could affordably approximate the Miles M.61 by taking a six-passenger single-engine plane, and stretching the "passenger" section down a few feet combined with stubby little gear.
     
  11. Mar 28, 2019 #111

    Riggerrob

    Riggerrob

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    Hanging stuff outside your airplane solves several problems if you don’t mind the reduction in cruise speed.
    The newest Murphy Radical is advertised with a bicycle hanging under each wing.
    One experimenter added a streamlined baggage compartment (think Cessna 206 and 208) big enough to haul a light motorcycle. That would be ideal if the airstrip was a few miles/kilometres from town. Tie down your airplane. Ride your motorcycle to a restaurant and a motel ......
     
  12. Mar 28, 2019 #112

    BBerson

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  13. Mar 28, 2019 #113

    billyvray

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    Plans please! I have a running ad on barnstormers, even if only a scan. I'd love to see the details of that thing! Mr. Oneill used to be on here but hasn't in a while.
     
  14. Mar 28, 2019 #114

    BBerson

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    The Magnum article is in Sport Aviation archive.
     
  15. Mar 29, 2019 #115

    saini flyer

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    Matthew, here is a design exercise:
    1. 2+2 seating equivalent payload: ( 175+175+100+100 = 500 lbs for occupants)+ 50 lb luggage+120 lbs fuel=670 lbs
    2. For a LSA gross weight this forces an empty weight of 650 lbs
    3. Can be put together by a first time builder with even more ease than RV12 build and also faster
    4. Removable wings by using the RV12 wings and Panther's ease of sliding out and rotating (https://flywithspa.com/more-on-panther-wing-fold/)
    5. High wing for ease of getting in and out for all payload
    So here is my contribution to this based on the existing RV12 setup:
    1. Use two Aluminum tube boom placed apart at the current width of RV12 spar connection pins on the fuselage
    2. Put a robust structure for the cantilever wings like the Panther and extend the mount to get a Rotax mounted (similar to FX-1 from innoaviation: https://www.innovaviation.com/fx1-aircraft/)
    3. Use the same tail feathers from RV12. The rear boom and the tail feathers will look more like a mini-skymaster
    4. Everything is almost at the same W&B location with similar moment arm as the RV12 except the front seat is moved slightly forward to use the spar as a head rest(similar to location of the Cardinal spar). Also the engine cg moves a few inches to the rear as compared to the current RV12 engine location but the moment arms should balance.
    5. The gas tank area in RV12 without gas tank can accomodate 200 lbs if the fuel is moved to the empty CG location of the aircraft which is where the pilot and passenger sit. So move the gas tank behind the Rotax using that space effectively that is right at the empty CG of the aircraft with enough volume for 20 gal. fuel.
    6. Attach a pod that carries no aerodynamic loads and is good for crash survivability and landing gear loads and make it big enough to have space for 2+2 and some(for getting two mountain bikes in after front wheel is removed). The rear of the pod will be flat and angled to increase overall volume and reduce drag. This will also open up to become a ramp for loading and unloading from the rear.
    7. The Pod is almost flat from the fornt door hinge to the rear.
    It definitely has more FPA than a RV12 but should still do well with smaller gear legs in terms of performance(maybe not 140mph and only 125mph in cruise).....
    and the concept to scale: 2019 March 28- High wing 2+2 RV12-2.jpg

    So maybe it cant transport a car but a small electric motorcycle/moped/scooter/bicycle (even two) can be accomplished in a LSA formfactor with two on board....
     
  16. Mar 29, 2019 #116

    cluttonfred

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    I like the configuration a lot but I would question a few of the basic numbers. First, why shoot for the RV-12 and LSA weight as the reference when four seats will disqualify it from LSA/Sport Pilot? Second, I think you have underestimated average pilot passenger weight (your numbers are 50 lb off in line 1) and aircraft empty weight. Third, why go for a cantilever design when a strut-braced design with the same materials yields a lower empty weight and this role needs to maximize useful load?

    LSA gross weight is about 600 kg, and an empty weight of 60% gross weight seems like a good rough estimate for a cantilever design, call it 60% for a strut-braced one. That leaves 240-270 kg useful load and I suspect that the extra 30 kg is going to be very important. So I'd probably go with an estimated 240 kg empty weight and an allowance of 90 kg per person and 40 kg standard fuel (53 liters/14 U.S. gallons). That leaves 50 kg for baggage/transportation, which is enough for a couple of electric scooters and two carry-on bags or a couple of mountain bik camping gear, etc. for a weekend. I don't think you're going to do a lot better than that at LSA weight.

    One approach I could see for your layout is make it a side-by-side two-seater with folding/removable seats and a flat floor long enough for camping even if the rear part of it is off-limits for cargo and only used on the ground, perhaps with a small "kickstand" to keep the airplane from squatting on its tail when you are moving around the cabin when camping.
     
  17. Mar 29, 2019 #117

    Victor Bravo

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    One of our Solidworks gurus (that's you, Sockmonkey... Fritz is busy with the Ranger) should come up with a concept where you have two bikes or scooters that strap onto semi-enclosed fairings on each side of the cabin. Entry and exit would have to be re-thought, or perhaps the cabin doors can be built to take that extra weight. The forward fuselage "boot cowl" could widen out enough to create a nose fairing in front of each bike, and there can be a rear "pressure recovery" type fairing behind the bikes. The doors would have to be made stronger and heavier, and the latching system would have to transmit more loads into the door frame.

    OR... you could take an Aeronca or Cub type fuselage with the door on one side, and mount the two bikes on the other side with a better and cleaner fairing.

    One obvious change from a standard Champ or Cub is that the horizontal tail would have to be a little larger because the bikes will put separated air (a larger "boundary layer" next to the fuselage) all the way back onto the tail. But this layout definitely has the potential to allow one or two reasonably full size bikes, scooters, etc. to be carried on an otherwise normal size and shape airplane.

    Admittedly this is less of a cargo plane layout and more of an external load layout.
     
    Last edited: Mar 29, 2019
  18. Mar 29, 2019 #118

    cluttonfred

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    To VB's point about bike racks, I think you dould do it pretty easily leaving them hanging in the air. Something along the lines of the Thruster ultralight (classic open two-stroke taildragger and sleeker enclosed four-stroke trigear examples below) would work well. It's easy to imagine a rear fairing that opens up like a clamshell with the bike racks hanging on racks from the boom tube and other, heavier baggage behind the seats. Folding bikes would probably still make sense to keep the fairing smaller and the weight forward.

    open taildragger two-stroke thruster.jpg enclosed trigear four-stroke thruster.jpg
     
  19. Mar 29, 2019 #119

    Sockmonkey

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    If it's just a pair of bicycles you could just hang one on each side of a strut-braced wing from the hardpoint where the struts attach. Bikes have a very small frontal area after all. Clamp them in place with an additional brace to keep them from swinging back and forth.
    Keeps the extra weight close to the original CG.

    I bet you could use one of those enclosed pedal-cars as the body of a light aircraft. Leave the airplane bits and engine at the airport. You avoid the complexity and/or redundancy of having two engines or a complicated power train. The planes Cluttonfred posted just above are suited to that. The airplane bits are a complete assembly on their own.
     
  20. Mar 29, 2019 #120

    Riggerrob

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    Dear saini flyer,

    Your sketches resemble a Russian prototype from a few years back (post fall of USSR). The Russian plane has two small engines.
    You are correct in simplifying your design to only 1 engine. With your overly optimistic weights, you will need the latest Rotax 914 which generates 130 horsepower.

    I am not sure why you want to install twin tail booms. Sure, early, tail-loading, military, cargo planes (Gotha glider, C-119 Flying Boxcar, Nordatlas, etc.) needed twin tail-booms to clear their massive clam-shell doors, but later designs (Miles Airvan, Bristol Beverley, Chase/Fairchild C-123, Lockheed C-130, Hercules, Shorts Skyvan, etc.) achieved better cruise speeds with parallel fuselage sides surrounding a tail ramp.
    Hint: The longer the fuselage sides - and the gentler theslope of the aft fuselage belly - the smoother the airflow.
    As for aft fuselage structure, may l suggest carrying most of the tail loads through the top and sides of the aft fuselage? Short tire ramps are enough to adjust for various loading surfaces. Definitely hinge ramps to the rear edge of the cargo floor .... only a short distance behind the main wheels. Perhaps swing ramps upward and lock them into the ceiling to prevent cargo/cars/motorcycles from sliding too far aft.
    The underside of the aft fuselage can be merely flimsy fabric because it only serves as an aerodynamic fairing.

    I am not clear on why you want cantilever wings. Strut-braced wings can be lighter and easier to fold. Struts can work like jury struts to stabilize wings when folding and stowed. Since wing strut fittings are farther apart, they carry lighter loads and can be built lighter. With clever design, strut attachment bolts can serve double duty as hinge pins, minimizing the number of complex, highly-stressed parts.

    Struts only produce a little more drag at your projected air speeds. Look at all the DHC bushplanes, Shorts Skyvan, etc. with wing struts and fixed landing gear.
    As for folding geometry, look at the British Luton Major.

    If you want to get silly, look up the ficticious Handley-Page Howdah.
    Hah!
    Hah!
     

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