Lightest Plane in the World: Design Criticism and Discussion

Discussion in 'General Experimental Aviation Questions' started by Two lane aviator, Oct 1, 2014.

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  1. Oct 1, 2014 #1

    Two lane aviator

    Two lane aviator

    Two lane aviator

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    Hi again

    sorry for "spamming", but this might be a good challenge for all of you:

    Designing the lightest possible aircraft using my parameters, like:
    Motorglider-ish and based on a Pietenpol Sky Scout.
    A slightly longer takeoff run is okay.
    Minimum possible HP (lightness considered)
    As cheap and as DIY as possible
    Performance like a Pietenpol
    Open cockpit
    Nanolite category is preferrable
    Rag-and-tube construction
    Average handyman buildable


    This is my first design: 1970795_664774386925625_9034680102802466071_n.jpg (more pics coming soon)

    What should i improve on it?
     
  2. Oct 1, 2014 #2

    highspeed

    highspeed

    highspeed

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    The Pietenpol Sky Scout is far from the lightest aircraft in the world. Weights will vary some, but it has an empty weight of 250kg. Another plane of similar configuratin, the Fly Baby, has an empty weight of 274 kilograms. This gives a pretty general idea of where single seat wood and fabric open cockpit homebuilts fall. It is possible to do more with less. The Arnold AR-5 did 344 km/h on 65hp at a gross weight of 300 kg. That airplane is a fiberglass, closed cockpit taildragger with a lot of careful design work. You're not going to make a motorglider out of an open cockpit, wire-braced rag and tube airplane. There's just too much drag.

    In the US, ultralights are 115 kilograms max empty weight. A nanolight would be even smaller than that. I'd suggest you sit down and write down some realistic requirements and constraints. Things like payload (you), range required (not far, if you want it to be light), speed (slow). Then you can work from those requirements to find the right combination of wing loading and power to weight that meets the requirements. Read Topaz's thread on his motorglider design for an idea of what is involved. Go buy some books. There are some excellent suggestions found on this forum. Designing an airplane is fun, but it's work. Without the analysis all you've got is a pretty picture.
     
  3. Oct 1, 2014 #3

    bmcj

    bmcj

    bmcj

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    There are plenty of examples of nano-light aircraft, some may have been successful, others not so much. With as light as some of these examples are, I don't see where you could better that by more than a few percentage points (if at all).
     
  4. Oct 1, 2014 #4

    cluttonfred

    cluttonfred

    cluttonfred

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    Weight is really just a question of time and money, a bit like the old quote attributed to various people, "If I'd had more time, I'd have written a shorter letter." Time so you can eliminate unnecessary bits and use complex methods to save a little bit here and there. Money so you can use exotic and expensive materials. Why bother? There are a number of simple ultralights of the general Pietenpol layout (open cockpit, parasol wing, wood and fabric, tractor prop, taildragger): Ultra-Piet, Loehle Parasol, Fisher Skeeter, etc.
     
  5. Oct 1, 2014 #5

    Tiger Tim

    Tiger Tim

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    There's also the Texas Parasol and while it's of questionable quality, plans are online somewhere for free.
     
  6. Oct 1, 2014 #6

    nerobro

    nerobro

    nerobro

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    A texas Parasol, or air camper design are far form the lightest airplane you can make. You need to pick where you want to spend your effort. If "light above all else" is the goal, you're going to end up with a very different plane from "fits the microlight standard" and a different plane from "Easy for the average handyman to build"

    You're going to need to pick a direction to head in. :) Or ideally, pick some speeds, and performance numbers, and weights, and work within those parameters. The rest will kinda fill in itself.
     
  7. Oct 1, 2014 #7

    bmcj

    bmcj

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  8. Oct 1, 2014 #8

    nerobro

    nerobro

    nerobro

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    wanttobuild likes this.
  9. Oct 2, 2014 #9

    BJC

    BJC

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  10. Oct 2, 2014 #10

    BBerson

    BBerson

    BBerson

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    The lightest fully fly able airplane I know of was the original CriCri at 138 pounds.
    It took the designer 10 years to perfect his design.
     
  11. Oct 2, 2014 #11

    Victor Bravo

    Victor Bravo

    Victor Bravo

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    Making a nano-light aircraft where the entire purpose of the project is the airplane's hyper-nano-micro-OMFG-lightness is going to be a huge disappointment to you. You will be spending hundreds of thousands of dollars, taking years and years of engineering time, and you will be spending a lot more money renting a large blimp hangar at Tustin, CA, or Tilamook, Oregon or Moffett, CA to fly it inside.

    After you fly it the first few times, you will realize that you have created an enormous expensive hangar queen, and you will spend money storing it until yo u finally celebrate the day when a museum accepted it as a donation.

    However, if it is the "lightest possible aircraft" you are after, then my suggestion is that you start studying the construction of the MacCready/AeroVironment aircraft, and their unique developments in materials.

    By the way, after you're done with the $500K carbon filament winding machine you bought to build your airplane, please donate it to a non-profit charitable aviation foundation that we'll set up for the benefit of HBA forum members. We have a bunch of educated and enthusiastic people who want to make tube spars and filament-wound D-tubes for some really neat projects...Thanks in advance :)
     
  12. Oct 2, 2014 #12

    Two lane aviator

    Two lane aviator

    Two lane aviator

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    1957 Stits SA-8 Skeeto Specs
    [TABLE]

    Length

    18 ft. 0 in.


    Height

    7 ft. 0 in.


    Empty Weight

    175 and 265 lbs.


    Gross Weight

    400 and 465 lbs.


    Wingspan

    24 and 30 ft. 0 in.


    Total Wing Area

    120 and 150 sq. ft.


    Fuel Capacity

    2 ½ gal.


    Cruising Speed

    45 mph


    Maximum Speed

    55 mph


    Service Ceiling

    50 ft.


    Rate of Climb (best)

    250 fpm


    Serial Number

    301


    Engines tested

    4 hp, Continental, one-cylinder, 4-cycle
    2.5 hp, Continental, one-cylinder, 2-cycle
    (2) 2.5 hp, Continental, one-cylinder, 2-cycle
    7.5 hp, Homelite chainsaw motor, one cylinder,
    2-cycle. 9 hp, Disston chainsaw motor, two-cylinder, 2-cycle.
    9 hp, Disston chainsaw motor, two-cylinder, 2-cycle, inverted.
    25 hp, Evinrude outboard motor, two-cylinder, 2-cycle, inverted.
    25 hp, Evinrude outboard motor, two-cylinder, 2-cycle

    [/TABLE]

    This would be the base aircraft, all we have to do now is "modernize" it.
    Do some safety upgrades and aim to use the lowest possible HP

    And think more out-of-the-box in terms of weight saving.
     
  13. Oct 2, 2014 #13

    proppastie

    proppastie

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    thanks for the thread and replies, I am inspired

    We could use the Filament Winding machine for the Steam Rocket Launch Tank.
     
  14. Oct 2, 2014 #14

    Two lane aviator

    Two lane aviator

    Two lane aviator

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    2522.jpg

    would this do for the plans?
     
  15. Oct 2, 2014 #15

    henryk

    henryk

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  16. Oct 2, 2014 #16

    Dana

    Dana

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    The original Quicksilver weightshift was, IIRC, 140# with the 15hp Yamaha engine... and was a very marginal aircraft, requiring near calm winds to fly safely. But the lightest practical aircraft is a powered paraglider, well under 100# ready to fly.

    Dana
     
  17. Oct 2, 2014 #17

    BillM

    BillM

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    Look at the KR1-B, it fits most of your requirements
    BillM
     
  18. Oct 2, 2014 #18

    bmcj

    bmcj

    bmcj

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    The Pterodactyl Fledgle empty weight was listed as 125 lbs.

    I think you'd be hard-pressed to find anything as light as the modern paramotor rigs, though.
     
  19. Oct 2, 2014 #19

    Aerowerx

    Aerowerx

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  20. Oct 2, 2014 #20

    bmcj

    bmcj

    bmcj

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    70 kg = 154 lbs
     

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