cardboard and duct tape airplane

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by wadeedward, Feb 9, 2006.

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  1. Feb 22, 2006 #21

    tankboot

    tankboot

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    Daniel,
    It is entirely possible (in my humble opinion) to build an aircraft from a lumber store depending on the materials chosen to do it. For example, Douglas fir is 23% stronger than Spruce, but 26% heavier so you have to make adjustments for this. It can be done.
     
  2. Feb 22, 2006 #22

    wadeedward

    wadeedward

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    That, was mean.

    Have you never heard of the saga of Lochead? The early boys never, never, attempted to say that silly computations could possibly beat experiment. Why the vega was built before much of our testing equipment even was thought of, and there are examples still flying of those increasingly rare birds.

    And even if one does the math one finds that a box section increases the durability of the structure...IE: one could hardly say the Langley's flyer wasn't a tad over-engineered. I believe he even hollowed out his wing formers to get rid of that nasty trend of the center making the load bearing outer portions weaker.

    I still maintain that the statement that there is a trend toward "stronger" in larger structures is valid. First off, the word stronger means "will not fail".

    I suppose those that want to say in court that "that darn bunch of bicycle builders" really weren't worthy of a patent would disagree, but it was Otto Lilienthals math that got the center of lift too far forward making the earliest fliers vary dangerous machines indeed, and indeed killed Otto Lilienthal (sic)! Math without testing is dangerous; but it does give "enlightened" and litigious twits an argument in court.

    A structure with a higher % of cavitation (IE: a larger structure with the same amount of material thickness) must (dare I repeat it? yes I dare) MUST be more resistant to failure from flex. If this were not so as a general trend withing the constraints of reasoned limits then as a general trend box sectioned wing spars would never have become popular. Your statement would lead one to believe that a spar without a box but rather a slit would be the stiffest possible structure(ideal in a world where "smaller scale for a given cross section" increases stiffness.)

    An example: I agree that a "German Over Engineered" Rabbit is a "stiffer car" than the Dodge Omni (virtually a copy of a Rabbit but with a thinner gage steel used practically throughout and 30% larger while the same weight). But if I were going to fly one of those cars I would pick the one that flexes a bit but has a larger wing and therefore lower loading. Airplanes aren't cars. But both cars don't fall to bits too awfully fast but it's the air that fails the stalling plane, not the structure, and that is why most planes crash, not due to structural failures of any sort, period.

    My plane will be pushed or pulled about with very little power; It will be on the ragged edge of stalling. I want a bigger wing, not an over engineered one. I don't care if it flexes and makes silly lawyers nervous; they don;t have to wear the crutches if it stalls.

    Blame God for wind sheer if you want, but I blame the courts for ascertaining sometimes that you nit wit "engineers" are smarter than all the Wright brothers put together!

    Cite a practical example of what you are talking about! Please. Let us behave as men of science. Let us put forth testable doctrines, not silly mumblings about the definition of "strong".

    Take the mosquito bomber of WWII for instance. It had thick skin sections, from a metal plane engineers standpoint. But this most successful airplane of it's day, built though it was of plywood and balsa could carry as much as a B-17.

    The balsa in the mosquito's wing acted as today's foam cores and the plywood acted as today's fiberglass or other "high tech wonder material". (In my mind I substitute egg carton cardboard for the balsa and reinforced cardboard for the outer skins on this new creation I'm working on.) I wonder, how thin could such a designs plywood skin theoretically be if it didn't need to cope with that weight? This is what I meant by my statement that bigger is better; such a light weight structure would have a ridiculously low wing loading. If the wing were thin enough (in sheet thickness not wing cord) I suspect it would bend quite a bit before failure (deflect with gusting wind or as in the rubber plane I've experience with -flutter)! - And I could test this on the ground safely! Thus, I might be able to reduce my likelihood of doing an Otto into the dirt from 500 ft.

    I also note that cardboard can be cast or steam "bent" into interesting shapes that are naturally strong (IE: arches). I note that general trends in modern aviation are to rely on single sectioned wings (not as safe, but I'm sure somebody did the math - so an idiot like me who looks for general trends should shut up I suppose!)

    I work from the perspective therefore of the minimum practical thickness that will provide the needed structural integrity. FAR FROM CONSIDERING THAT CARDBOARD IS A POOR CHOICE, I find that cardboard might in fact be an ideal choice, just as the engineers of the F4D chose corrugated aluminum of a thinner gage for that really fast climbing fighter plane of your (IE: light basterd weren't it? - misspelling intentional). Yes, I want to fly only 1/2 hour! big deal ! the Japanese flew cardboard balloons half way around the world!

    Forgive Me,
    Wade
     
  3. Feb 22, 2006 #23

    orion

    orion

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    "Mean"? No such word in engineering. Blunt, maybe - but not mean. The principal function of engineering and the math that you so obviously have no respect for, is simply to keep one alive - has nothing to do with lawyers, despite any espoused conspiracy theories.

    Otto Lilienthall had the math and the basic theory, unfortunately he did not have the practical experience to understand what it meant to have the CG too far aft (Cp too forward). Furthermore, he did not have the security acumen to keep his flight attempt from being sabotaged (current day tests indicate that his airplane would have flown quite well).

    The Wright Brothers on the other hand did not have the depth of math skills but they did have the logical mind set and approach that allowed them to take basic theory and apply it, thorugh years of tests, towards their success.

    While their work needs to be respected, it should in no way be used as an example of a viable approach to today's projects. Much of their success can be attributed to plain luck. Today for instance we know that if their engine put out just two more horsepower the airplane would have failed structurally shortly after it left the ground.

    People also use the Wright Flyer to justify the use of foreplanes (canards), as if somehow the Wrights hit upon some mystical truth in their development. However, if one actually reads their memoirs, the pitch control surface was placed up front as a form of crash protection just in case the airplane flew into the ground.

    Contrary to your assertion, I did not indicate that computations beat or surpass experiment. Experimentation is an important part of design in that it verifies not only the math but also the processes and materials used within a structural element. With such verification, the math becomes more accurate and thus more dependable. Today we have almost a hundred years of applicable mathematical and experimental verification and yes, it works and yes, it's accurate if you have the necessary background and know what your'e doing. Coupled with loading requirements set forth in publications such as the FAR's, there is little or no reason why a safe and efficient airplane could not be designed by theory alone. The only limitation of the process is the inexperienced designer's lack of practical understanding of all the interleaved and interdependant effects. And often, many of these are very difficult to test for. This is where the math becomes predominantly important.

    I'm not sure what point you were trying to make with your Lockheed Vega example but the mathematical analysis and design of aircraft structures preceeds many of those designs, usually by decades. The analysis of beams, shells, reinforced monocoque assemblies, etc. dates back to the 1800's. Some of it even further back than that. Some of the best, most accurate and most detailed texts on aircraft design were written and published in the 30's and 40's. Due to their accuracy, many of these are still used by designers to this day.

    I'm sure that with a very careful approach of building and testing you can probably put together something airplane like that just might stay up long enough to win your bet. I however have seen too many of these trial and error projects where those behind them based their design on "faith" and their own interpretation of design and engineering disciplines. Some of them are no longer with us.

    In short, the engineer's function is simply to try to keep one alive. If it requires a two by four aside the head and bit of cold water to dampen the enthusiasm and make the amateur designer take a step back and recognize his or her shortcomings, then that's a good thing. Blunt, yes. Mean, no. If you take the advice to heart, you'll stay alive. If not and continue with your own less than kosher ideas, then that's your decision too although that decision may have significant impact on the rest of your life.

    Either way, good luck.
     
    Last edited: Feb 22, 2006
  4. Feb 23, 2006 #24

    J.L. Frusha

    J.L. Frusha

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    Bigger ain't Stronger

    Take a piece of paper and wrap it 10 times around a pencil and the same papaer around a paper-towel tube. Which one flexes easier?

    Now, take the same paper and make a tube 1-foot long and another 3-feet long(with the same number of turns,...duh). Which one breaks easier?

    Some flexibility is necessary in any structure. However, there is no substitute for structural integrity.

    Don't take us as atagonistic, we want you to succeed. However, what power does success have, if it costs you your life?

    By pointing out the desired result, shouldn't you consider other options, than merely trying to bull your way through? Obviously, you seem to think you know 'ALL' about this, but you instigated the discussion... To what purpose?

    There is no victory in being to injured to pursue your business proposition, merely a final defeat. If, however, you want to succeed and further your business proposition, try considering your options.
     
  5. Feb 23, 2006 #25

    Falco Rob

    Falco Rob

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    Hey Orion,

    Don't be mean (blunt!) - that's a future Darwinian Award candiate you're talking to!
     
  6. Feb 24, 2006 #26

    tankboot

    tankboot

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    cardboard?

    My grandfather gave me several peices of advise as a kid, most of which I didn't understand till later in life. Some of which are not appropriate for listing here. Here is one of them:


    There are two kinds of people on this planet son, You can send them both to the same schools, givem' the same books and the same teachers....but ONE of those two, will always be stupid.


    My personal list of the 10 most stupid people:

    (In order of stupidity)

    1) people who stop at yield signs
    2) people who stop in a driving lane to turn, when a "turning median" is provided for that purpose right there in front of the idiot. (even equipped with turning arrows none the less)
    3) People who stop at the end of an exit ramp. (these people should be shot on sight)
    4) People who drive slower than all surrounding traffic in the FAST lane, then get angry when someone rides there butt. (these people should be strung up in a public place and endure 5 days of electro-shock therepy)
    5) People who buy the "crap" off those paid infomecials for $39.99 in 5 easy payments, then sell it 6 mos later, at a yard sale for .50 cents
    6) People who "rent to own" furniture/appliances
    7) People who buy mobile homes (cause we all know there worthless long before payoff)
    8) Any person who will buy a firearm cause it's "cool" and not know how to properly use it before hand.
    9) People who will actually cuss a police officer after they are given a ticket?
    10) People who will argue points of a subject they know nothing about.
     
  7. Feb 25, 2006 #27

    wadeedward

    wadeedward

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    Hey Everybody,


    First off, by know you already know why I have few friends. I am consummately arrogant. I have found this a necessity in my life. I didn't used to be arrogant, but I've few if any options, being as clever as I am, and that being my only real gift.

    Secondly, by now you know I'm a know it all. And by saying know that I know that I don't know. But I suspect I know more than many of you are thinking I know.

    I ask you this has anyone ever taken a paper, wrapped it around a pencil that is ten feet long. Then taken out the pencil. Then taken a piece of paper, wrapped it around a toilet paper roll ten feet long and removed that underlying roll. Then progressively removed support from one of the ends of both observing which fails first? I think that would be a more dramatic variation on the paper roll experiment. One could show the whole class all at once, even those who are Quadriplegics in wheelchairs.

    When I was a kid, I was exposed to the wrap a pencil demonstration. I never felt I was coordinated enough to do it properly. (Of course, I was six months old I think...)

    In any case, I hope nobody is really mad at me, I'd hate to be thought poorly of. I mean, it's not like I'm not willing to share my thoughts.

    Speaking of thoughts, What do you guys think are the odds of getting a cardboard and duct tape airplane contest going? I mean, it would be nice to not be alone in trying to build one.

    I mean, somebody had the private spacecraft race to space thing; couldn't we get a "race to grace" going? I can see homeless shelters all about the country getting involved if there was some incentive, perhaps even just publicity... One might even have schools build cardboard and duct tape airframes as a means of teaching valuable skills. (I put it to the local boy scouts and surprisingly they aren't overly enthusiastic - yet).

    Well, yes, here's to Darwin. There's hope for evolution yet. (Or is that Eve's volition?)

    As for the empirical Datum to plug into the formulaic: Consider a simple bare wing in Clark Y with 1/2" thick x 1/2" hollow with 1/4" hollow thickness honeycomb base "skin" under a 1/8'' thick X 1/16" rib hollow with 1/16" wall thickness corrugated "intermediate skin" of typical egg carton type cardboard under an 1/8" ribbed corrugated cardboard of 1/500" paper with a single 1/1000 "separator paper between these elements and an two ply outer cardboard skin of 1/500'' total wall thicknesses with moderately sized (say like a 3-6 pound test fishing line) fiberglass reinforcement strands (these being hollow if possible) bias plied at 1/8 inch intervals. Center on the wing a 73" reinforcing tape as wide as the fuselage and the portions of each wing reinforced. Make this as per the outer dual ply outer skin. Seven inches in from this place a second reinforcing layer in the same manner and 7" in from that a third layer and 7" in from that a forth layer for a total of 5 layers of dual ply paper with reinforcing in fiberglass. Inside the wing one does a mirror of this as one is building it for 10 layers. This should amount to about 1/8 " thickness for the outer skin at the fuselage. The wing is taped to the fuselage at this point and additional layers are added as needed.

    Make no allowances for ailerons other control surfaces; I've got a novel idea for that that might work better with my "delicate" wing.

    Alternately figure the system without honeycomb but rather opposing corrugations with like dimensions. Honeycombs are less proved.

    Use the same formula for the fuselage and tail group. Allow for the instances wherein there can be no whole first, second or third layer due to overall thickness constraints, wherein the layers should be considered from outside in shaving down those layers to fit in the middle with the equally shaved layers of the other side but keeping the papers between layers. at leading and trailing edges place a second reinforced paper shell. on the tail group have this wrap about top and bottom as would a seven inch tape, on the wings leading edge a 40 " tape and on the trailing edge of the wing a 10 " tape.

    Check for weights at this point. Factor in pressurization of the outer skin to stress it to 10 psi.

    I'm to do a structural analysis of the wing; see if such a wing can support itself, the fuselage and tail group and 500 lbs. without further supports. I've a psychologist working with me to make sure I don't stop breathing thinking about it and to provide biofeedback as it were.

    All cardboard to be made on open cell foam molds, or preferably cut into ice or snow molds, taken off and then assembled. Shredded news papers are to be used to make the "egg carton" layers, perhaps mixed with micro-balloons to vary the weights.

    I'm going to be short of supplies of course being a deadbeat and all, I'll look into alternatives for micro-balloons. Good quality packing papers to spec for the shells, if I can get them, news papers if I can't. If I cannot get fiberglass, because I am destitute, I shall look into other available fibers, such as salvaged cotton from the Salvation Army Store. Eggs and milk might yet find a way into the glue materials list as well, as I can get these at the store with food stamps (heh heh, we'll see if that'll fly!) And I've two good leather jackets that could go for glue if nothing else seems to be "good enough". (I once knew two fellas that made a prop using laminated wood up north - they used a moose for the glue.) - I suppose road kill glue would do in a pinch... someone should check for me if squirrel makes for good glue stock ! Crows are plentiful around here too and I'm not feeling sympathetic to them taunting me either so they are candidates for the glue pot as well.

    So, does anyone know what the best home made glues are? Are there "special" formulas to use to make better glue? I have a good library handy but you guys are the experts...

    And, there is more hope fellas! I've been offered leeway to use milk jugs and soda bottles!

    As for Engines, I've got two slightly bad but quite possibly functional 5 horse Honda engines; has anyone ever turned one into a two stroke for more power? Would they hold up? Could I use nitro on these beasts to increase the HP reliably without resorting to the true "funk" of trying to convert these to 2 stroke operation? Where would I get nitro? (For Free) . Can one make nitro easily? (NO2) Would It be "safer" mechanically to build a small boiler and run this into the engines to convert the rigs to steam? That would be true cave man; steam powered paper airplane!!! Langley would be proud! (His first unmanned ship was steam powered - the one that didn't crash!) I like it from a Mainer's perspective too! Stanley's were invented here.

    Of course I'm playing about with the formula as yet. I'll let you know as I grow the beast...



    Wade
     
  8. Feb 27, 2006 #28

    wadeedward

    wadeedward

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    Hello again,

    I have further thoughts on the corrugation.

    Has anyone experience in the manufacture of "specialty corrugated paper", made with paper straws ? If such straws are pressurized then they should self clamp if properly positioned on the mold of a wing when the top layers are placed on top of these.

    I like the straws idea because it places more density in the vertical elements, also, failure of one doesn't mean failure of all.

    Thus far, I'm imagining placing the straws on a wooden temporary female mold all at once and clamping the ends to the edges of the mold, very gently steaming these straws and and then suctioning the straws to bend them while stretching. Thus I hope to prevent crimping, and the resultant weakness. In my minds eye I imagine these crimps to be the place where an element will fail first.

    I'd have to be careful not to place too much glue on the straws, so as not to glue my straws to this mold. (and / or use a non-stick trick such as plastic wrap.)

    Then I think steam the top paper, and together stretching this over the mold and either clamping it down or both clamps and a weighted box with an inflatable bag in it to provide additional clamping.

    To take full advantage of the benefits of the safety factor of having each straw "covering" the other in terms of redundant stiffening to all vectors (to keep the wing from folding up should one straw burst) I'm now thinking layering the corrugations differently. I think now AVROE started to have a good idea in the Wellington Bomber's wing in this regard. I'm thinking two opposed layers of diagonally placed "clutching at straws" (consider that copyrighted) corrugation plus a top layer of corrugation that places the ribs with the wind and with smooth papers between all and on the inside and out.

    The wing would thus be built in six steps on two molds (top and bottom).

    These procedures would of course work equally well in aluminum or other materials, substituting other forms of heat for the steam to plasticize the metal.

    I look for critique on the notions presented.

    I do intend, however, to test various methods in hope of producing the ideal wing from these materials and have far from given up on the honeycombed egg carton material idea for a base material. I've done some rudimentary tests already and this seems to produce a viable substitute for foam. (I bent an egg carton in the kitchen and compared this to a foam egg carton! If anything the paper seems a bit better...) We'll see...

    So, What I'd like to know, if anyone should have the time to inform me, what are the very best ways to test such wings?

    I know a few ways already. But I'm always open to better ideas.

    How does the FAA do this nowadays?

    God Bless,
    Wade Edward
    :ban:
     
  9. Feb 28, 2006 #29

    Topaz

    Topaz

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    The only useful critique I can offer is that I think you're taking this a bit overboard for the requirements. Half-an-hour at 50'+ altitude?

    Corrugated cardboard is very stiff if used properly, and all this talk of pressurization, laminating special materials, female molds, etc. strikes me as trying almost literally to create the Concorde out of paper. To win your bet, this thing doesn't have to be pretty or fly the Channel. If it staggers into the air and stays there for 30min, you win.

    Keep it simple. If you can bend the rules to the point that you're allowed all those other non-standard 'cardboard' materials, go with fiberglass-reenforced strapping tape instead of duct tape and use it liberally for local reenforcement on a structure of conventional corrugated cardboard. I'd even imagine you could lay up multiple strips of the stuff as a sort of laminated spar cap. A couple of layers on a 45deg. bias covering both sides of a sheet of corrugated might make an adequate shear web. Roll some cardboard up into a tube several layers thick and you've got a nice lift strut. Curve the cardboard into single-curvature shells wherever possible and try and do a monocoque-like fuselage structure. It'll keep your parts count and weight down, too.

    Keep it simple, keep it as light as possible. If getting it light enough for a given engine requires too much technology, go get a bigger engine.

    The most important thing is to test, test, and test some more. Build samples and load them up with sandbags to make sure they'll withstand the loads you've calculated for each part. You're using non-standard parts and non-standard 'fasteners' to put them together. You won't have any idea if they're strong enough until you weight them up and see for yourself. No sense in becoming a statistic just to win a bet.

    That's my opinion, your mileage may vary.
     
    Last edited: Feb 28, 2006
  10. Feb 28, 2006 #30

    wadeedward

    wadeedward

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    Hello again everybody,

    No, Topaz, I think not. "normal" corrugated cardboard likes to be flat, wings aren't flat. Fold that stuff and one weakens it.

    Corrugation offers so many advantages that to simply use card seems a poor choice, but I suppose if backed by egg carton honeycomb or microballoons and egg carton card it might be well within the limits of sanity.

    As for molds, these can be made of cheap stuff too; one can use ice for instance. Ice in Maine comes free with the weather. Why not use a mold? Why not make straws? I mean I've got time. The govornment insists I make $30,000 per year or nothing, and the former just ain't going to happen - especially since I need to "keep up" this rate of income for over a decade if not forever if the kids are declared mentally ill; so I've nothing but time.

    The idea of crashing from 50 feet is horrific to me, as it should be to anyone. (It was a typo anyway - the bet I'm reminded is 500 ft. up for a half hour). I know from helmet studies that a man can die at 35 mph with a helmet on.

    Failure is not an option. It would be unpatriotic to tax the medical system while so many war veterans are suffering from legitimate injuries ( should some doctor make the mistake of fixing me it might hold up a soldier's recovery ! )

    Of course, I would no doubt survive even a complete airframe collapse...I mean 500 ft, over water, what would that be like? Certainly it would be no worse than crashing my motorcycle into a brick wall naked at 80mph. (No computations made - just a guess).

    As I mentioned earlier the static testing we did on that rubber rescue plane weren't adequate. We lucked out on that one when the various forces started flapping the wings the compression wires functioned as both flying wires and an odd sort of friction damper. But at least twas learned that better testing would seem to be a good idea.

    What you seem to say is data is not available for inputting into a finite element analysis program with regard to cardboard. Is this a fair assessment? If so, how might I go about composing my own program, or modifying an existing program?

    I cannot imagine finite element analysis has not progressed so far as to be able to "deal with" corrugated aluminum, as useful as corrugations are in engineering. It would also seem that pressure variations on such programs would be important considerations as well, as at height the elements of a sealed wing would naturally be under the influence of internal compression unless these were built in a vacuum chamber, and even then the wing would only be pressure equalized at a specific height for a specific barometer reading on the ground - more or less.

    Speed also would also tend to stress portions of the wing internally on a differential to other parts. Doolittle's famous studies on relative pressures should guide us into the conclusion that parts of a sealed foam and fiberglass wing are subject to dynamic compression whilst others are subject to dynamic decompression. Even if wings did not actually climb into thin air they would be subject to pressure differentials.

    Surely programs that Analise wings and recommend thicknesses take these stresses into account in 2006?

    Hm-mm, what will these pressure differentials do to my pressure filled straws? I'd best see how much pressure they can stand without bursting!

    By the way, does anyone know the findings of Doolittle's tests on dynamic pressure differentials so I would know just how much pressure differential my straws would be exposed to? Once known I could devise a test to see if this pressure would burst the individual straws.

    As I said, the psychiatrist is to be working on this with me, but any help would be of use.

    And thus far we intend to utilize that Russian freeware that's out there. Has anyone any experience with it?

    Thanks Again,
    Wade Edward
     
  11. Mar 1, 2006 #31

    wadeedward

    wadeedward

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    I'm back,

    Here is another thought to put into the formula:

    In terms of the simplest possible means of "steering the beast" I have come up with the following: Balloons can compress and act as air springs that place their stress along a large area. Also bladders can fill with hydrolic fluid and act nearly the same way with regard to stresses imposed on the airframe. Either way, no measures need be taken to provide traditional hard points on a wing to gain the action of an airleron or flap nor need any measures be taken in regard to tail surfaces to provide for traditional hard points as a control surface system needn't be any more complex than an air or fliud bladder taped to the wing with an optional stiff cover, with a hoze and a similar bladder in the cockpit. Of course presures used should be quite high in a gas system.

    I am reminded of an early glider that employed springs to dampen flutter. The springs chosen were too weak and consequently when the controls were tried at speed the controls were locked by dynamic pressure from the air flowing over the controls. The wiggling of the stick merely caused the springs to collapse without moving the controls at all. A like condition can occur if one uses airsprings if the pressure inside the bladders fails to exceed the relative exterior dynamic pressure the controls will of course lock.

    A hydrolic system can be based on bladders. It might even be possible to control an aircraft with just the rudder peddals using bladders. by varrying hose sizes one can restrict the flows on the different bags for different portions of the whole system and stack bags so that collapsed certain valves are turned off for varried rate controls. By rolling a peddal, like the gas peddle on a car, one can decompress one series of bags while compressing another. By Pushing one can do the same. Thus one could control all of the control surfaces by the feet alone. By linking all the actions in one part of the brain learning coordination of "stick and rudder" might be easier, because it would be roll and push, instead. One would also use heavier duty muscle groups. Flying might get less exhausting, especially for women - they have weaker typical upper body strength I'm told.

    For my purposes, as I've vertually no memory of flying, I've nothing to forget, so I shouldn't get any more confused. Learning the system shouldn't be a trouble.

    As for building it, I think I can get away with making bladders out of duct tape, providing I have multiple redundancy. Other parts of the system would include reinforced gas line for tubing and throttle cable and engine brake cable for linkages. A bent engine brake lever should suffice for the peddals and pivots, and the whole gizmo would be suspended by the cables themselves so I wouldn't have to worry as much about getting caught up in the rigging if I crash. (Remember that scene with Leonardo Decaprio getting stuck in the plane? The right foot was caught under the rudder peddal against the crunched underside of the H1.)

    Any thoughts on this would be appreciated. Has it been tried? Would the Air Force use it with crippled no arm pilots?

    God Bless,
    Wade Edward
     
  12. Mar 6, 2006 #32

    J.L. Frusha

    J.L. Frusha

    J.L. Frusha

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    Cardboard and what?

    Perhaps I misunderstood the topic...

    Thread says Cardboard and Duck-tape. Under that definition, you wil have H*** pressurising anything.

    IF you laminate cardboard on a diagonal, you can strengthen it, without fiberglass-anything. I'd say 3-5 layers of corrugated with the center horiz, next 2 on a 45 deg angle,
    and outers vert. ...Boom, a light, sturdy rib. Add a cap of poster-board and you get easy skin app.

    Duck-tape is NOT going to withstand internal pressure.

    If, however, you have all of these other fantastic materials available, why ask about an extremely low-budget bird inthe first place?

    As for the physics involved in structural design,... Most of the 'math' can be done in Algebra.

    IF this is to be a design with no real cardboard or duck-tape, you have lied, repeatedly, about the aggreement and your financial ability.

    That, further, designates you as a willful 'dead-beat' Dad.

    That's worse than mere neglect. You should be ashamed of yourself, for the reality of the situation and the true nature of the neglect you impose upon your offspring.
     
  13. Mar 6, 2006 #33

    wadeedward

    wadeedward

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    Hey Everybody,

    What fantastic materials have I referred to JL? Road kill perhaps?

    What I have mentioned is building my own cardboard's as nobody makes a pre-bent cardboard and wings aren't flat.

    People do call paper based egg cartons "cardboard egg cartons". It may not be corrugated card, but is a cardboard and it is free for a fellow on food stamps.

    Around here news paper is also available free, so a poor quality cardboard is infinitely cheap (as my fellows seem to think I am.)

    Milk and Eggs are free as well to a fellow on food stamps and glues and lacquers can be made from these. In the case of eggs, it might even be legal, as many recipes call for only whites or only yolks; so whatever is left over is trash and therefore legally usable.

    I ask the moderator to censure you in regard to your statements about my "offspring". There is nothing in the law that states the children need be a "deadbeat dad's" offspring for a judge to find anyone in contempt of court for child support. Indeed, the in Maine law specifically states one needn't be a father to be declared a deadbeat dad, or prevented from competing with those of a different political bent by the deliberate manipulation of marital and divorce law, providing the judge "feels it's appropriate".

    Given political rhetoric that claims it's criminal to force a conservative to pay taxes I suppose a finding that liberals deserve jail in all cases is in line with conservative "feelings about what is appropriate". I honestly state no effort has been made at granting me personally even so much as a fair civil hearing, especially in that last round of "divorce" (there was 1/3 of a decade between the final divorce and the one the judge and ex covered up) and in Maine civil law does in no way require such effort from a judge; for instance the children are not deemed biologically mine by blood test and despite reports from myself to court officers that evidence exists that the ex with this judicial in the room planned and executed parts of a plot that involved child abuse and horse tranquilizers and the Internet. In short, I'm grasping at straws for a reason.

    But I am wise I believe in stating that straws can be made to fly. God himself will in a storm force a bit of straw through a piece of plywood, proof that God agrees that the weak should occasionally be empowered with flight, and "superior stuff" is often beaten by really weak stuff when air power is deployed properly.


    You might be right about the duct tape hydrolic controls though. I'll surely test it when I get enough bartering returnables to get some reinforced duck tape!

    God Bless,
    Wade
     
  14. Mar 9, 2006 #34

    J.L. Frusha

    J.L. Frusha

    J.L. Frusha

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    C & P, + Duct-tape

    Perhaps I mispoke. At Some point, there seems to be a refferal to fiberglass, as I recall... Not saying my memory is perfect.

    How about this? Check out the models in Walmart. There's a flying wing that uses 2-channel R/C. It uses 2 motors for all control functions. Slow both, for decent; increase one to turn, etc.

    Looks a lot like the F-117 Stealth Fighter, but might be adaptale to your project... maybe cross it with the Maersk Monarch, thus lowering the CG and increasing the stability...
     
  15. Mar 11, 2006 #35

    CAVMan

    CAVMan

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    Wade,

    I've been following this thread with growing interest, and have made every attempt to remain impartial through some of the more heated discussions. A lot of interesting points have been made on the subjects of mathematical analysis, experimentation, and material use. The key to producing a successful product is taking all of these factors and let the scientific process run its course. Use every bit of information provided and test it and research it until you come up with a workable combination, but for safety's sake use the proper proven techniques on your endeavor.

    Now that I've been on my soapbox, I've got some humble suggestions to throw your way.

    Most of your project seems to move away from the aero-engineering aspects, and more towards structural and material engineering. Like with any engineered product, it's not the composition of materials used, the weight of those materials, or the inherent strength of an individual material, but how these materials are incorporated into the finished product that will determine its success.

    It sounds like you may be trying to focus on one type of cardboard for your project because a single characteristic that you are attracted to. As you know, there are many types of cardboard materials out there, each with its own strengths and weaknesses. Use a variety of the materials available to you, incorporating each in an area that will benefit from its strengths. For example, corrugated cardboard has a high compressive strength, so why not laminate a couple of peices(or use doble walled corrugated) to use as ribs in your wings. Rolled cardboard(the thick ones) resists deflection, which might make it ideal for your spars. Cardboard used in gift boxes has high elasticity properties, which might be useful in skinning, allowing the skin to properly transfer stresses to the ribs and spars.

    Personally, I would tend to think that the use of cardboard would require an actual fuselage, and not just a spar frame. This shouldn't be unreasonable using a traditional semi-monocoque design.

    Definitely wouldn't stray away from traditional control features, the project sounds complicated enough.

    Good luck and safe flying
     
  16. Mar 27, 2006 #36

    planecrazzzy

    planecrazzzy

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    Paper is Heavy

    Paper is TOO heavy....The weight would add up TOO fast...

    I wouldn't WASTE my time......What would you end up with.....?

    Something to laugh about....

    Go Kill yourself in a different Hobbie, Don't bring attention to mine...


    Gotta Fly...
    Mike in MN / N381PM
     
  17. Mar 27, 2006 #37

    J.L. Frusha

    J.L. Frusha

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    Waterproofing

    Read something interesting that could be applicable, as cardboard and paper are nothing more than wood-pulp, "Thompsons " water-seal could be used as a light-weight water-proofing agent.

    Another thought... If you took corrugated cardboarg and creased it across the corrugations, folded it over and glued the sides into a double-thick box; then boxed that, with some more, with corrugations going lengthwise, you could build a spar... First part might be cut, so that you slip a box-shaped 'tab' into a 'slot'; for splicing of shorter inner pieces together... Could be rectangular or triangular...

    As for bending a skin, I'd still stick with kraft-paper, at some $7/roll, 36" wide, thats pretty low-cost and still conforms to the idea of cardboard or paper.
     
  18. May 17, 2006 #38

    velojym

    velojym

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    tankboot: It's Kobiyashi Maru

    Anyway... is our esteemed thread starter still alive? I would hope he's having better luck than the straw which, though airborne for a time, was not in a mode of flight I'd care to try.
    If cost is the issue, I'd have some ideas (which, of course, are not my own but I'd throw 'em in the hat anyway), but the bet seems to be paramount.
    I don't suppose the bet is monetary, then, given what we've read so far. Just don't fly it in the rain ;)
    Yep, I'm rambling like an idiot cuz I'm nothing like an aero engineer, and I never stayed at a Holiday Inn either. (I pretty much live in Choice Hotels... the nature of my job and it keeps me away from my wife, dogs, and 801)

    Allright, I'm bored. I guess I could go brush up on my AC 43.13 or something...
     
  19. May 17, 2006 #39

    Topaz

    Topaz

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    The whole thing had the smell of troll. I'm sorry to say I was drawn into it, too.
     
  20. May 17, 2006 #40

    J.L. Frusha

    J.L. Frusha

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    Paper Too Heavy?

    Last time I checked, Paper was the initial covering for most of the original gliders... Even the Japaneze suicide rockets were bamboo and paper, in WWII.

    Bamboo and Balsa are nothing more tha naturally formed wood-fiber.
    Corrugated cardboard is man-made, but structurally as capable as structure and covering as anything else...

    Heck, even the Montgolfier Brothers used paper for their balloons.

    It'll fly, if the design is structurally sound and has proper power/weight ratio. That's why I suggest using them as alternate meterials for something reasonably normal.

    I think the pressurised straw idea would take too much engineering to make, using low-buck materials...

    It need not be practical, to be possible. He only has to make one flight, to prove the concecp and 'win' his bet.
     

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