Why not roadable aircraft

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Himat, Jan 26, 2012.

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  1. Apr 27, 2014 #761

    Aircar

    Aircar

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    Those figures quoted by Terrafugia are patently ludicrous but in any case the basic issue is the stipulation of WEIGHT as some sort of valid criteria for how much you can penalize an aircraft compared to another one (via excessive certification procedures) --weight is NOT a criteria for setting 'standards' for any experimental aircraft and neither is it used to categorize cars in terms of what engineering justification is needed and finally it has next to nothing to do with actual flight safety or any other related matter.

    Wingloading (in take off or landing configuration -ie near to the ground) IS a meaningful quantity but more than that is actual minimum useable speed --in the case of Terrafugia they got a little too clever and deliberately set things up so that their ACTUAL minimum useable speed on take off was over 80 MPH even though the nominal stall speed was conforming to LSA --defeating the idea of docile near ground characteristics (the Slovak Aeromobil has a 90 MPH take off speed for much the same reason - to do with weight distribution on the wheels ) The pilot is not aware of the WEIGHT of the aircraft he is flying and it is not a primary factor in anything of significance --certainly not to the level of a hundred pounds or several provided the real factors that matter like wing and span loading,inertias etc are the same . Making anything out of all carbon fibre and not trying to save weight by external bracing for example,using three wheels or using any high lift devices,etc already forgoes any claim to have cost or 'best efforts' in mind and deserving some bending of the rules --they ignored advice freely given to them before going ahead along a path to predictable failure.

    What IS the LEGAL basis for specifying WEIGHT as the criteria for treating one aircraft differently than another ? ( I had to look into this in regard to the same issue in Australian certification exemption weight limits [the 'under 400 lb AUW' ultralight class of ANO 95.10] -it turned out that there WAS NO legal basis for it --aircraft could only be categorized by FUNCTION ,not weight,colour,national origin or any other irrelevant factor --the regulations were admitted to be invalid and they had to be rewritten (a process still going on many years later ) Bad engineering and conception cannot be attributed to some arbitrary legislation either.
     
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  2. Apr 27, 2014 #762

    N15KS

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    It is my understanding that some of their exemptions are temporary. They must address those safety issues within the next three years or cease production.
     
  3. Apr 27, 2014 #763

    BBerson

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    I think the three years from the 2010 exemptions have already expired.
    Carl announced at Oshkosh 2013 that deliveries are scheduled for 2016.
    I wouldn't count on that either. It seems to me the modern business model is to delay indefinitely, while having fun with investors donations.
     
  4. Apr 27, 2014 #764

    Holden

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    BB,

    Legislation (regulations) is to keep the competition from entering the market, which is the opposite intent of the commerce clause. Welcome to modern BAR insanity.. Add in a bunch of requirements and keep other entrants from competing. Oldest trick in the book.

    Holden
     
  5. Apr 27, 2014 #765

    Holden

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    Aircar,

    The issue is whether some burorat can pull some number out of his rear and force us all to comply with there whim or belief contrary to actually engineering data. Traffic tickets are a good example. Some believe wrongly that they can just post a speed. No, they have to do a traffic study and determine what the 0-100% of the flow ranges normally, and then they are supposed to put the "limit" which is NOT a limit, at the 85% median. The 85% is the minimum risk driver. The risk curve goes from 14 times the risk at the 0% (slowest driver) down to 1 times risk at the 85%, and back up to around 5 times risk at the 100%. Notice they allow slow risky drivers, but get all bent out of shape with a faster driver at 1/3 the risk...insanity. All the "speed limit" is is a notice of minimum risk. The "persona" of speed limit gets people to drive at that speed as determined by the study. Crash risks go UP when the speed limit post is lower than the 85%. In essence, by not following policy (nation wide....85% is the standard) local governments create "fishing zones" for taxation by citation. Total scam. They actually risk people's lives with this nonsense and then claim immunity from prosecution. Total breach of fiduciary....

    The same insanity is upon us with LSA and much of the FAA nonsense. In the name of safety, the rats are risking lives. They don't have any data to back up their religion and they use the force of government to perform their inquisition. Next thing we know they will want to burn us at a stake for not following their beliefs. Sick puppies.

    Holden

    Nihil simul inventum est et perfectum. Nothing is invented and perfected at the same moment.
     
  6. Apr 28, 2014 #766

    Doggzilla

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    That may be true, but lets try and tone it down a bit.

    You make some of the best theoretical posts on the forum, lets not get sidetracked. Got to pick your battles, and we all know that nobody has really made use of LSA.

    In reality, LSA might as well not exist.
     
  7. Apr 28, 2014 #767

    Aircar

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    We ended up with a situation where just about every stipulalted maximum or limit was unrealistic in practice so that exemptions were 'granted' in each application or simply no action was taken for extreme breach of the weight figures so that the law became a laughing stock to say the least. the old saying 'the law was made for man not man for the law' (or some variation of it ) is the salient point . If some arbitaray and indefensible legislated figure was holding up the business of the nation or national security or something else of significance then the legal hurdle would be removed post haste --that may in fact come to be the case with flying vehicles but certainly is not for leisure aircraft so I don't think anyone can hope to rely on 'rights' or some obligation of government based on entitlement of some kind . Finding a generalized principle in the constitution or common law that can be invoked is a better bet -just as the "Oregon outlaws" argued that the pre amble to the US constitution protected the 'right' to pursue happiness (by building your own aircraft -normally a trade or business activity rather than a path to nirvana )

    On latin "nil carborudum bastardum", -don't let the bastards grind you down.
     
  8. Apr 29, 2014 #768

    henryk

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    Last edited: Apr 29, 2014
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  9. Apr 29, 2014 #769

    Aircar

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    Henryk - while I appreciate your contributions to HBA could I just ask that we stick to the topic in each thread rather than just posting amusing oddities unrelated to roadable aircraft in this case . I have a very slow connection now and it takes up a lot of time to get something to come up only to find it is nothing to do with the subject , so please --just things that are directly related to the thread topic please.:nervous:
     
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  10. Apr 29, 2014 #770

    henryk

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    -after Rome\JPII\ last weakend journey I was decided to eliminate footh controll elements,
    ONLY hand controll devices \motorcycle like...\

    BTW,dont worry Aircar=soon will be working connections with
    ifinity speed \torsional fields\...
     
  11. Apr 30, 2014 #771

    henryk

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  12. May 1, 2014 #772

    Velko Velkov

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    My idea for Flying car.
    It is compact, universal and realistic.

    Flapping Wing: FLYING CAR 3
     
  13. May 1, 2014 #773

    oriol

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    Welcome to the forum Velko!


    Despite that a double rotor (or any kind of heli/gyro configuration) allows for great level of compactness for road use. It is very expensive (a turbine is cost prohibitive) in terms of fuel consumption, very noisy and dangerous for anyone around when the rotor is moving.
    You will be disturbing everyone in the neighborhood every time you take off or land: it would be prohibited to operate at night at least.

    My guess is that your idea looks more feasible for the army rather than for civilian use.



    Oriol
     
    Last edited: May 1, 2014
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  14. May 1, 2014 #774

    Velko Velkov

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    Oriol, thank you !

    Combustion engine(s) is possibility for helicopters and Flying cars too.

    Velko
     
  15. May 2, 2014 #775

    Sockmonkey

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    Not to be all negative, but the thought of trying to drive something fragile enough to fly down my state's chewed-up roads on a regular basis makes me cringe.
     
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  16. May 25, 2014 #776

    henryk

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  17. May 26, 2014 #777

    henryk

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  18. May 26, 2014 #778

    jedi

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    This is a new and refined version of Slovak designer and engineer Stefan Klein. He is the designer, builder and pilot of the Aeromobil. I presume it is a similar configuration with one piece folding wing to the rear, without twist (ie. wing remains horizontal) and with a long shaft to a pusher propeller. I think it retains the long wheelbase and inability to rotate and therefore lifts off in a level attitude with high wing incidence similar to the B 52 and B 47 bombers or bicycle gear of the U-2.
     
  19. May 26, 2014 #779

    henryk

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    =wing incidance is +12 deg. ,and -30 degreas flaps for take off...

    -I was asking about small car modell with strange rotors autside wheels.

    http://www.gulf-times.com/NewsImages//2014/1/19/c33292bb-e422-4d33-817d-7de795922e5b.jpg
     
  20. May 26, 2014 #780

    jedi

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    No explanation. I can only speculate that perhaps those are to keep other vehicles at a distance to prevent parking lot road rash.

    I can not make out any wheels. Could these be a wheel substitute?

    Please let us know when you find out more.
     

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