We're obliged to all of you who offered suggestions yesterday as to how to adequately join the recently-arrived paper straws which will form the structure of the Paper Aircraft Released Into Space (PARIS) Vulture 1 vehicle. We got straight down to testing a few alternatives, including PVA and superglue, but there was one option …
these guys did it before
Read up about a similar project here: some quality hobby engineering. And yes, they didn't restrict themselves to paper.
"We don’t know where in the world the plane will land, but it would be nice to send a message to whoever finds it."
hope it doesn't fly all the way to Singapore, or you might earn yourself a hefty littering charge.
I was somewhat bemused to note that in Aircraft Restoration circles when they restore a Mosquito to flying condition they throw all the wood away and only keep the metal parts...
This is because the glues have a limited lifespan - some 30 - 40 years. Not an isue for Paris of course:-)
I once built a car out of wood. Wooden wheels, wooden gears, wooden engine and so on.
It wooden go!
that is all
to read this with a wooden face!
OK, own up...
...how many folk initially thought this was an article about a completely different Paris? ;)
re: own up
Not from the title, as P.A.R.I.S. is well established by now, but during the article, "butt joints", "slits" and "hot glue" - my warped little mind almost imploded with the double entendres that ensued.
Yup, I had a bit of a funny turn at seeing a whole article based around getting ones hot, sticky fingers on PARIS's bits.
I look forward to the future article alluded to, detailing the careful application of exotic substances to PARIS's skin. After that I may need a lie down.
I don't want to add a tedious or demanding item to your task list, but I would very much like to know at least approximately what percent of total weight of the plane minus payload is actual paper. Coatings on items not constructed entirely by your crew, such as the aforementioned straws, might prove challenging, but is it too much to ask that each component be weighed before being incorporated into the structure?
[black chopper just because it is also a flier]
Are you offering to use your extensive understanding of numerology to predict the outcome of the mission? :)
thats a gagaism isn't it?
Naaaoooo: Dont use Hot Glue
at least not for the real thing.
Melts when it gets hot (obviously) but doesn't need to be as hot as you may think.
But also, crucially, it gets very brittle when it gets cold at altitude!
Stick a sub-assembly in the freezer overnight and see how it holds up.
I was thinking of suggesting silicone "instant gasket" as an alternative with a wide temperature range, some of those products are quite sticky too. Then I remembered what SRB "O" rings are made of and how they held up when it got a bit chilly.........riiiight.
Any idea what they stick tiles onto Space Shuttles with*?
* @ Anyone saying "chewing gum and spit", yes, very funny, but most of them actually *don't* fall off.
Try using polyurethan book binding glue.
"Books bound by PUR will not fail at extreme temperatures — even over 200°F or under -40°F." (http://americanprinter.com/pur-binding/printing_pur_perfect_binding/)
Don't know if that temperature range is sufficient, though...
"Any idea what they stick tiles onto Space Shuttles with*?"
NASA calls it "Room Temperature vulcanizing" adhesive which AFAIK is the description of the stuff people use to stick wall tiles up for bathrooms and kitchens.
It's high temperature limits is not quite as high as you might imagine. (IIRC it's something like quite low. I'm pretty sure the tiles would fall off before the maximum use temp of the aluminium body is reached, which is 183c). It's big feature is it can handle the on orbit soak temperature while remaining flexible, which is *very* low, something like -150c to -200c (in theory it could be down to the universal background of 3k but a fair bit of heat leaks out of the orbiter)
The temperature gradient from front face to back face of tile is high.
Your choices for glue are basically A) Cyanoacrylate (Super Glue) or B) Some sort of epoxy.
A) will get you quick dry time, high strength (much higher than the paper it's binding together, anyway,) good low temp performance, and light weight. CA will also work nicely to attach paper to your tube trusses, which will make them quite a bit stronger.
B) will have to be carefully selected from the large array of epoxies out there, will take a while to try, and may require curing at an elevated temperature. The upshot is that there is such a selection out there that you can get basically any performance characteristics you want - high temp, low temp, perfect shear modulus, etc.
The key is to keep the glue as thin as possible, and don't fool yourself about how long that inner piece of the butt joint needs to be - at some point (rule of thumb is about 2x tube radius, one radius inserted into either side) the straws will fail before the joint does, so making that inner piece longer is just going to get you more weight. If 2x radius isn't long enough, put one segment inside the tubes and another outside, that'll balance in-plane torques due to tension and prevent delamination.
Tip: For construction, get yourself a nice ceiling tile and a bunch of large T-pins, print your layout at 100%, put that, covered with plastic wrap on the tile, then use the T-pins to hold pieces in place on top of your print out. That lets you make sure everything fits before gluing, and that it stays put during gluing.
Not sure this is a real engineering project
Because I haven't heard mention of gaffer tape yet.
There's also a suspicious lack of photos of men with pipes and a garden shed.
re: Space Shuttle tiles
Or to paraphrase all the sciencey answers, it doesn't matter what they stick the heat tiles on with - it's protected by the heat shield.
high end of temperature range
my extensive research (searched amazon for "bradbury") allows me to give you the high end of the range.
I leave the cold end to other comentards
Suggestion: I believe your joint will be stronger if you are able to tease apart the helical joint of one of the two straws to be joined end-to-end. Make a shorter slit in the still intact straw, apply glue, and quickly wrap the helical strip around it. You will end up with a structure that will combine your original method of reducing the diameter of the end of one straw, increasing the diameter of the other straw, and distributing the operational torsion dynamic forces radially and symmetrically.
Side note: Do not be tempted to drink your beer through the straw to test the seal. Drinking beer through a straw make the beer very fizzy and will make you burp uncontrollably. Drinking whiskey (or for that matter whisky) through a straw is OK, though.
Sounds like a good idea but a lot of extra work. It would produce a lighter weight joint as well.
I have to confess that my first thought on seeing the comment title was that the whole project must have come about as a result of a few too many strong joints!!
A human could follow it...
...since a man already jumped off a weather balloon 30km up. Too bad the man would dive faster after a few seconds...
What would be the terminal speed of PARIS, assuming the man got faster than Mach 1 (without a plane, that´s commendable) at a given altitude?
Can the terminal speed be guessed, since it is way lighter, but it offers also way less resistance?
Should it survive, won´t it break the world record of 'longest flight of an unpowered paper plane"?
Why do you need this structure?
Have you guys looked up Rogallo's experiments? His design amounts to a sail which looks very similar to a paper plane, and it forms the basis for hang-glider and modern stunt kite designs. It also assumes the load (an Apollo capsule for Rogallo; the GPS and camera for PARIS) is slung underneath it for balance, which is kind of sensible.
re: Rogallo wing
Are you sure you're not actually thinking of Gemini -- and not Apollo -- as the manned spacecraft originally proposed for the use of the Rogallo gliding 'chute for CM recovery?
Mark Wade writes at:
Manufacturer's Designation: McDonnell-Douglas. Class: Manned. Type: Spacecraft. Destination: Maximum Payload Orbit. Nation: USA. Agency: NASA. Manufacturer: McDonnell.
The paraglider was supposed to be used in the original Gemini program but delays in getting the wing to deploy reliably resulted in it not being flown. McDonnell proposed that additional Gemini missions be flown to fully test the paraglider, which was planned for the follow-on Big Gemini."
Mea culpa - wrong mission. Still a good design though, as proven by a lot of pilots.
Didn't this have a slight problem with its wings falling off?
I have seen a genuine wooden piston- which was working fine in a 1930's austin seven- apparently a piece of seasoned oak heartwood boiled in oil for hours and then machined was up to the task...
low compression, low volatility fuel flame obviously
getting even further off topic
I've always wanted to build an engine out of lignum vitae, just to see of it's possible.
the wood is tougher than most metals and self oiling. (It's so tough, you don't cut it like wood, you machine it like metal!)
But... at the prices it's going for, that'll remain a pipe dream.
( http://www.lignum-vitae.com/ , and there's more on wikipedia, if you're interested)
Wood pistons used as running repairs in Africa
Remember IC engines are pulse heating systems. The piston of any given cylinder remains fairly cool most of the cycle.
Now making the whole *block* and cylinder head out of wood is a whole different thing.
The P in PARIS....
....would be plastic then.
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