Peters Aircraft factory flyable paper models

[PetersAircraftFactory]

Hi Mike! Thank you!

My goal would be to make my models ligthweight and avoid balance weight / or to reach, to structural reinforments do this purpose. However usually i have to use balance weight. Gripen for example is nose heavy, and need a little tail balance, while for example F-84 is tail heavy, and requires nose balance weight.
On Gripen, I used two reinforcement box, to make it durable, and it also gives it's realistic shape. But it also makes it nose heavy.

On F-84, I made the hook from paper, and also it reinforce the nose partialy, and gives the balance weight.


Sometimes I "cheat" with the wing position, I bring it more forward with 1-2mm, to move forward the resultant lift force, and avoid the usage of balance weight. I made this with the MiG-21. I moved forward 2 mm the wing, and it does not need balance weight.




Rubber band: I just stick together the rubber rings with scotch tape. On a model forum, I read bour rubber band models. They wrought, if you knot it, it will make the rubber weaker, and can tear at the knot, as the rubber is not scretches equal on it's lenght.
I use different amount of rubber to launch different weight models. I have launcher from 3x1, 3x2 and 3x3 rubber ring. This means, the launcher is 3 rubber ring long in all case, but at the first, I stick together 3 simple ring, at the second, I make doubler ring, and make a 3ring long chain from them, and at third, I stick together 3 piece, and make a 3 ring long chain.
The lenght is limited by my arms, as I can't fully pull back longer ones.


Mig-21 works well with the simple and fly great with the doubl one. It weight circa 5 gramm. I push back full lenght the rubber, because it can withstand good high speed, because delta wing.

Hawker hunter is 6 gramm, and I fly it with the double one, however I don't push the rubber back full lenght, just circa 70-80%. I can also launch it with full pull back, but it is too fast for the model. It will make a very fast looping, and at the end of the pooling, it will close to the ground, and can't glide long. If I launch it with 70% pull, it will not doing loop, but goes high, and glide far from there.

I tested the EE lightning also with rubber, however I didn't upload video about it.
I had to fit the hook under the intake. First I fitted it further back, but the resultant lift force was close to it, and there was a lot of failed launch. It is a bigger model, so it requires the triple launcher for high performance.


F-100 is one of my favourite project, however I had to reinforce the wing. It does not worked well with full pullback, and in wind. The wing bented too much at the wing root, and crashed. It is also a bigger model, and I reinforced the wing with a hard-paper part.
Beside this, I reinforces the nose with plastic strip. It moved the CG, so I had to apply more balance weight to the aft. It is a rather nose heavy plane.
Now it does not fly as good with modest pullback, at lower speed, but fly great with long pull back.
I will make an update with these modification in the manual, I plan to update a supplement file about these experiences.


There is a small field close to my home, I usually go out there, but I can launch there only with weak pull back. Because this, I also thinked about, to make 1-2 lightweight version of plane to there, which are covered only partialy with scotch tape.
If you fly slower, weight count a lot, and at there, weaker strcture is not a problem, as launch will not be as fast. This also true for indoor flight, and probably to glide models from a hill, however I haven't got place for that.



I also have to replace the rubber after a few hour usage, as it become elongated, and weaker. If I fly the model with an elongated, weaker, older launcher, it reduce it's performance. ( But, for example, at a small field, it is not a rpoblem, as I don't need a fast launch)


If you have several type of rubber ( thickness and lenght), you can avoid to "build" this type of launcher, and simply you can smake different launchers, but I bought only one type of rubber, whick contains circa 200 ring, so for the next 1-2 years, I think, I will use these.

About the tape, I use the common, transparent scotch tape, which is used in offices.
I usually cover the whole plane with it.

At the points, where there is a bigger stress, at the hook and at the handle, I use longitudial piece of tapes, to fix them, and I also fix the longitudial strips with cross-directional ones, to prevent tear-off. I tried to draw this in several of my manuals.

At the nose cone, I started to use a transparent plastic strip, cutted from plastic bottle.
I also usually fold on a stoch tape strip on the leading edges, to protect them from crashes.

And my models usually have internal reinforcement. I used plastic straw for this. It would be the best solution, as it is strong and lightweight, but it become forbidden product in the EU, for enviromental reasons, and you can't buy anymore.
So I switched to paper reinforcement, to make it easy to build for other peoples.
I usually make a triangle cross-section reinforcement, and stick it into the fuselage.
reinforcement is always reach the first part of the wing.
The fuselage it vulnerable, where it meets with the wing. It is usually a stress-point.

My other loved method, to make the fuselage from two half, and too the wing between them. with internal reinforcement it also realy strong, as there is an internal flat area under the reinforcement. It is some extra weight also, but works similar, like on the real air liners the floor structure. it also strenghten the structure.

I link the video about my latest outdoor flights.
Flying my paper models: 2024 02 10 - YouTube

[mbauer]

Thank you for the explanations. Makes lots of sense. You truly understand aerodynamics a couple of levels beyond my knowledge.

Like the thought of wing placement as you describe.

Really like to check this thread to see what you have got flying next.

Thank you for sharing your models/technique with us.

Mike

[PetersAircraftFactory]

Thank you, however it is just experience. I 've seen, you designed rubber powered paper models also, and you have experience to build flyable paper planes in big scale. That will be new for me. I will try my FW-190 upscalled with rubber band, that is one of my future plan.

My next project probably will be this PZL TS-11 Iskra.

[PetersAircraftFactory]

SU-7 flying paper model ( with tamplates and manual) - YouTube

This was the first time, I used SketchUp for design, so I choose a relative simple model.