Tetra Packs (Milk) + Food packaging foil
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Hi guys,
First of all, thanks for the Powerup(4.0). It's just pure awesomness... and a good way to learn aerodynamics, too. It should be taught in school! :-)
Not sure, this forum is intended this way, but I just wanted to share my latest joy and success story with tetra pack(s) and food packaging foil. This combo allows stable constructions, water/humidity resistence and light weight.
Or, this one:
BTW, so far, I never had to use elevators. They are just exagerating pitch too much.
What I could actually need is some kind of expert lessons (how-tos) regarding the tuning setting in the app. I know - sort of - what the do, but I'm still lacking a lot of experience here to tune that right. Some expert kung-fu knowledge would be great to have.
Thanks again for making Powerup. This is just great. If Powerup5.0 comes along with some kind of elevator control or something, I'm probably in again. :-)
Best,
Sven
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Official comment
Thank you so much for sharing this inventive design Sven! If you have time share a video - we'd appreciate it.
Thanks
Steve
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Tetrapack: cut off top and bottom, cut away one side, then unfold the 3 sides of the tetra pack.
All glueing is done only with tape (eg 1 cm wide).
Other stuff like fin (on bottom or top) is done separately and also glued with tape.
Sometimes I also slice small but long rectangles of tetra pack and tape that on top or underneeth the front sides of the wins to move the gravity more forward.
Unfortunately, I lost my prototypes in the last house move. So I have to redo them again. I should really try to make a photo sequence or video of the stuff. Sorry that I haven't done that, yet.
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Ah yes, and I try to use the biggest possible stable part possible (3 uncut sides of a tetra pack is better than taped single stripes). And because, the tetra pack is stable but also heavy, heavy, heavy, I need to cut BIG holes and then "close" them with thin foil. I guess, you could also try to just use wide-enough tape!?
Center of Lift can be solved, but the weight is a beasty challenge.
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Additional: in the mean time I built a similar plane. Initially without 'plastic windows' . I used the Valkyrie timing parameters. The plane was hanging backwards during flight and had not enough power to climb, but made slow turns at full throttle.
Today I added 'plastic windows' and added a triangle of milk carton at the first 2 inch of the plane. The weight reduced from 7 to 5 gram. Unfortunately the plane was hanging backwards, but did climb a little better. I reduced the pitch kp value from 1 to 0.5 and now the plane was able to climb better than before.What I don't understand:
- the wing is completely flat, this doesn't create any lift, does it?
- Normal wings have a concave upper side, how come that all folded paper planes have this shape on the bottom side of the wing and that it still works to make the plane fly?- do I need to add more profile to the wing of tetrapack/foil? Will this increase lift at lower throttle? To me it feels like the plane is now flying on thrust only and use the wing to create more or less drag on either side to make turns
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I re-created a tetra/foil version of the Hammer Head, which IMO is the best plane as it got flaps in front and reverse one in the back. I try to make a photo documentation of the thing.
Regarding the Lift, I indeed have thrust and drag only and have indeed no form that gives lift via the Bernoulli's principle, for example. You're right. Last year, I experimented A LOT to get a plane "real" non-flat wings flying - big ones in the middle and small ones + fin at the rear, but I always gathered too much weight and/or could not ballance stability, CG (Center of Gravity) and CL (Center of Lift). However, I'm still eager to do so. My idea here is, to have a thick bar on the front of the wing and than wrap a paper (transparent paper) around it, such that the rear of the wing is thin while think on the front -> form! However, the summer last year ended before a first success... If you get this going, I'm eager to see it!
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OK, here's a first try of a documentation for my Tetra/Foil Hammer Head
BTW, I hardy use the read flaps, i.e., I leave them quite flat.I still have to find somebody and a good place to film the thing in action. The meadow I use is too small and surrounded with trees and buildings. Seeing the plane on the video is hard.
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Hi jakenl, what do you mean with "when I changed to a paper plane"? Did you rebuild your first design again with paper instead of tetrapack?
The (transparent) paper is a good mix and easier material and of course much lighter than tetrapack. Less stability but faster to build. I use both, the tetra pack and the transparent paper. However, really normal paper I don't ever use again. Do you?
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Change to paper plane: I had a paper plane with me as backup. Since the flight with the Tetra pack plane was not satisfactory, I put the module back on a paper plane.
Yes, I rebuilt de Tetrapack plane with ideas after the first flight. My aim was to avoid using the coin, since adding weight to an airplane is bad. Since I thought that the plane was mostly flying on thrust and steering with wing drag, I decided to make the following changes:
- Create lift by folding the the wings on the front (the tooth pick served this time the job to keep the fold down (I had now staple machine with me)
- Raise the props, since I thought that the thrust was creating too much momentum upwards (and therefore the coin for counterbalance)
Result: bad. The plane was pitching up even more and was not controllable. I had to both add the coin and lower the props to the wing to have a similar flight as with the original design.
With 'new' knowledge I think I did everything wrong that is possible:
- If the lift in the wings worked, it would push up the nose even more, since the wings start at the nose
- the removed part of the wing at the back would move the Center of Lift forward, pushing up the nose once again
- Props placement, I still don't know why this was working so bad.
So far I have not been able to find the transparent paper in any physical store, thefore I will have to buy from the Amazon link, I guess. The original Amazon offer is not available anymore, but there is a new link to the same product/price: 20 pages of tracing paper in 20 colours, A4 sized, 130 g/m², colourful parchment paper, colourful transparent paper for crafts, A4 tracing paper, lantern crafting : Amazon.de: Home & Kitchen
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Thanks a lot for sharing your experience! :-) I agree in *all* parts, actually. The tetra pack is bliss regarding stability but a mess when it comes to weight and "form". It was only an experiment. I also played around with balsa wood - but no success so far. I'm still dreaming of Powerup Glider...
I tested the Foam Jet (was included in my pledge)... but that's not my material. It's really light, but after all did not hype me. It may be me, but I'm not a fan.
The so far easiest and best compromise is the transparent paper. I often fold and tape the rear end (0,5 to 1cm) to get a harder, double-thick rear "line" that increases stability and also fix the correct plane length, so that the module fits.
Regarding CL: Yes, I guess, your CL was way too much towards the front - I guess that's also one of the reasons why my gliders are all not working (wings too much towards the front). Look at my post about the Hammer Head (Monday) - I really love how its front flaps work. And IMO this plane is very maneuverable.
Raising the props: I really had that idea too, and I guess, you actually moved it the wrong way. To get the plane's butt up, the props should push it up, and so, the props should point more down and not more up. But, anyway, my experiments here did not succeed really, too.
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I now have my all time favourite (Tetrapack) airplane. I used this website for the right dimensions:
http://scampownersclub.org.uk/powerup/another_plane.htm which is based on itself on a video of Kyle: https://youtu.be/RR3wPOJ8woQ
Initially I built 2 airplanes, 1 with and 1 without a 'window'. The 'window' saves 2 out of total 7 grams, quite considerable.
However, the plane with the window didn't want to fly, but flipped sideways. The root cause: wrong brand of milk carton :-) As can be seen below, one brand has the overlapping edges of the material in the middle of a face of the package and this ends up in the wing tip. This is enough to destabilize the plane so much that flying is impossible
Luckily there are more brands out there and obviously a different carton manufacturer:
The fold in the carton was not that strong to keep the winglets in shape, but I didn't believe in the solution of Kyle to use a strip of paper to keep the wings in shape: the Tetrapack material is used to avoid (wet) paper + the paper strip will add drag and also increase the chances of crashing while touching a tree branch.
The paper strip solution gave me a good idea for improvement though: the paper strip was stapled on in Kyles design. My addition to the design: use the staple itself to keep the wing into shape.
Here I just came back from the campground owner, asking her politely for some staples and her stapling machine. She had to dig deep to find it during these days of internet and email!
I simply bent the staples over the top of my finger and the winglets now stay in place for many flights in a row:
I am now happily flying this plane with the controls based on the onslaught. Over time I moved the slider for 'steering angle' from 130 to 75. That makes it a very agile flying machine
Yesterday I managed a single flight to empty the battery from 100-0%: 476 seconds of air time. The plane flies very stable on a decent amount of throttle. On full throttle it climbs like a fighter jet, so plenty of opportunity to go either easy or acrobatic on the plane by yanking it full throttle through tight curves or pull the plane up after a steep dive.With fall fast approaching the paper planes are not usable anymore, since the grass is simply to wet.
Since flying the plane is now so easy, I'm up to a new challenge. Maybe I should try to get the plane to loop or roll. I don't think I really managed that before.
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@Sven, thanks for your template. I built one of them during my holiday week in Belgium this week. Since I only had access to scissors and not to tape, I didn't make a window in the wing. I brought it with me on a day trip and on the way back to the cottage we came across a nice 'air field'. However, it was both (too) windy and the plane was not well performing. It was hanging down with its tail and hardly gained any height. Only when I folded the wing flaps down as well, it worked a little better, but very wobbly and with a lot of throttle.
Back at home I cut the window today and taped it up with a piece of plastic. At a first try it flew a little easier, but still not very stable on it's coarse. I modified it with a fin underneath it and that proved alright during a 2nd try. I also tried the app settings for both the Hammerhead and the FT EZ Bug, but didn't see a whole lot difference in flight performance.
My intermediate conclusion is that it flies a little slow and needs relatively high throttle (65%) to fly horizontal. I really like my other plane, since it is a lot more agile. My next try will be to move the wings back further on that plane and maybe even 'fold' the wings closer to the fuselage to see if I can make it even faster.
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Hi jakenl, thx for your rich insights. During the summer we had very bad weather in germany. I worked some days on a different (typical, non-fighter) air plane design, i.e. large wings in the middle of the plane, small ones + fin at the end (to keep props safe I always go for a downward fin like you).
I nearly achieved something good, was near to shoot photos, but then changed some ballancing and all the fun was gone. I can't wait for spring 2022 to continue this endeavour. If you really like a challenge try a plane with largs middle wings, too?
Have fun! :-)
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