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Stainless steel tubing for giant scale PA18 SuperCub

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Old 02-11-2012, 04:45 PM
  #26
pilotarix
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Jim
I am OK with sharing this thread, there is not so much information out there about brazed steel or stainless steel tube frames, so maybe we should keep the information together in one thread. My progress is slow anyway and I am just thinking about to continue the 1/3.85 frame, because I already put a lot of time in this one.
I also redraw the parts 1:1 from the original drawings using a CAD program, as you can see in the pictures I posted in the beginning of this thread. Unfortunately Im still struggling with some fittings and hinges, at this point of time I don't have enough precise machinery yet. For the fuselage I didn't use anything else other than torch, Dremel, some round files (the ones for chain saws are OK) and the Proxon disk sander. I finished the left landing gear couple of weeks ago, and figured out, that stainless steel with bigger diameter is not easy to handle, and today while I was planing the other one, I found out, that the measurements are not correct.......sh....
So I will order some 4130 (3/8 0.028) tubing and start from the beginning and try some welding, like Robart does with their 1/3 Piper landing gear.
I also attached a picture from my engine of choice. Is the Saito 4-stroke FG 57 gasoline engine, as I already mentioned, maybe a little bit to heavy for this size of plane.

more to come...

Chris
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Old 02-12-2012, 04:28 AM
  #27
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

I'm liking it.
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Old 02-12-2012, 10:42 AM
  #28
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Nice work Chris,
I used steel rivet barrels for hinge tubes, the mandrel than works as a hinge pin. You can get the rivets in stainless. The small parts, brackets, and fittings were all drawn on one page so that they could be lazor cut out of one sheet of .042 chromolly steel. Finding that it was kinda expensive I went ahead and expanded the drawing then glued glued the drawing on the steel and started hacking away. I found that an air cut off tool was invaluable for cutting tube . and the parts out of sheet material after using a small band saw. A hacksaw works well for this also. Harbor Freight adds and coupons help.

Mild steel seems to be working fine on several 1/5th and 1/4 scale cub landing gears that I built for practice. I highly recommend making a set of cub landing gear.from the original plans that are available at http://www.supercubproject.com/ See dwg 10033 for example. If you look thoroughly through this site you will also see how this person jigged many of his parts. Just a hint, jig your landing gear as though it was diving straight into the table. Then set a piano wire into a drilled hole at exactly where the hinge points would be. The wire can be squared to the table easily in a vertical position. This should position everything were it belongs.

You wont have any problem lifting that engine,you will have buckets of wing area . You will probably need nose wieght any way, although my kitten seems tho be pretty close to balanced.
On the original kitten, The pilot made up about half the all up weight. so it gives me some room to work with. If it comes out nose heavy, the batteries will be put in the pilot.
Sometimes I wonder if we just are not intelligent enough to realize we can't do something ,so we manage to do it anyway.

Keep up the good work, Jim

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Old 02-14-2012, 08:30 PM
  #29
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Hi,

@Jim, thanks for all the info.

I also had all the fittings on one piece of paper and found that laser cutting was much more expensive than I thought. I startet the same process on Sunday last weekend but unfortunately the result was not very convincing. I tried to cut as much as possible using tin snips, because the hacksaw was making much more noise than I thought, unfortunately I don't have a basement and I don't wanna stress test my friendly neighbors to much. Maybe after all that, I will think about laser cut again.
Anyway, I hope this problem will be solved once we have found a new house.

When I first started thinking about a fuselage from stainless steel tubes, actually after I visited the Piper museum in Lock Haven in October last year,



I did some research in the internet and also found the supercubproject site. I got all the drawings and started to transfer some of them into my CAD programm.







Then I did my own plans, took them to Staples and got them printed their in full size. I used them to make a jig, and therefore I got two identical sides of the fuselage.







Than I did another jig, to make the transition from "two dimensional into three dimensional", which was not so easy.





I made a kind of jig also for the landing gear, however I screwed it up. Next time I will follow your hint.

I ordered some 1/4" 4130 steel tubing, which arrived today. Now I am waiting for the Bronze-Nickel brazing rod, which I have ordered from Aufhauser Co. in NY. I hope to get everything together before the weekend.
There are a couple of videos on Youtube with an Aeroworks SuperCub (same size as mine) and this engine, seems to work fine, the only downside might be that the engine does not fit complete under the cowling.

Chris


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Old 02-15-2012, 09:26 AM
  #30
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Check out post 146 for fittings
www.rcuniverse.com/forum/m_9340619/mpage_6/key_/tm.htm
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Old 02-15-2012, 12:44 PM
  #31
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Wow, that's some fancy cad work. I recently widened a hanger 9 super cub cowl to fit a OS 160 twin, it's really hard to tell. Do you Know of a way to change autocad drawings into printable pdf documents.
It might be fun to post printable pdf drawings of J3 cub landing gear in 1/3,1/4,1/5,and 1/6 scales. We could include a build thread for cub main gear if anyone is interested.
Keep up the good work, Jim
.
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Old 02-21-2012, 10:43 AM
  #32
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Hi,
unfortunately there was not much time during the weekend to work on my little project. Yesterday I had some time to work with the CAD. Before I start on a second version of the landing gear, I will finish a detailed plan of the whole thing.
Once a plan has been done, it should not be a big deal to scale "up" or "down", but I would assume that 1/5 or 1/6 is maybe to small to make a "scale" landing gear.

OK, and here is what I have done so far.











This was probably the easy part, the harder part might be the actual suspension. Hope I will get that done until the weekend.
Comments Suggestions Modifications?

@Jim
If you do not have Autocad, the only way is, find a free programm that can load Autocat drawings and convert them into PDF files. If you want you can sent me one of your files and I wil see if I can convert them into a PDF.

Chris
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Old 02-26-2012, 04:21 AM
  #33
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Guys, glad I came across this thread a lot of good information here, I just got a set of plans for a half scale super cub am gonna start the LG when I get a order of steel, was wondering about doing the fuse framing out of steel and aluminun tubeing. I'll be watching and learning.
Mike
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Old 02-26-2012, 07:58 AM
  #34
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Chris;I like your welding fixtures,very nice.I built a 1/4 scale all aluminum using a product called metalweld and the thing is still holding together on land and with floats,the plans was a sig J-3.George.
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Old 03-16-2012, 02:16 PM
  #35
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

I love your method using the paper templates to shape the ends of your tubes so they fit nicely. What CAD program are you running. I'm guessing you took the tube part and converted it to a sheet metal part to create the template. Is this correct.

Leif
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Old 03-16-2012, 07:35 PM
  #36
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

Folks

thank's for your interest in my thread and sorry that I am so slow responding....
I try to solve the problems while things going forward and unfortunately I have a lot of them. I started with the idea to build a stainless steel-tube fuselage, like the original, instead of wood. The plan was to make that the"sole" modification at a Tony Clark PA18 kit from Germany. And in the beginning I never really thought about the problems that potentially could occur. So here I am, still in the middle of this "process" trying to find my own solutions.

I have the chance to use Solid Works for doing most of the CAD work, some CAD drawings were done with Alibre. The cutting templates for the tubing were done with Solid Works, but you can find also free software for that on the internet. And YES, it was done with sheet metal conversion. The cutting templates are useful for tubes with 5/16" inch and above. Below this diameter, I think there is no advantage anymore, because you barely can cut or grind smaller tubes as accurate as necessary.
I never thought about aluminum, because it is not easy to join the pieces. Yes, you can weld or even solder aluminum, but it is a way more difficult than soldering stainless steel tubes and I can't imagine that there is a real advantage in terms of weight. It might be less expensive and it is definitely much easier machinable.

If I would start from the beginning now, I would use the silver nickel alloy for the most important joints and 45% Silver solder for the "rest". That gives you the opportunity to work with different heat. And there might be less risk that while re-heating one of the joints, that everything falls apart.

In the last week I got my little lathe, which hopefully will give me the opportunity, to make some of the still missing parts myself. I have already made some bushings from brass to fit the diameter of the screws to the landing gear.

Chris

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Old 08-03-2012, 10:57 AM
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Default RE: Stainless steel tubing for giant scale PA18 SuperCub

I am interested in building a super cub fusalage with tubing. Gordon or anyone else that may know, how do I get ahold of the Graeme Mears plans? I found his facebook page but no replies from him yet. I bought all the plans from Northland Aircraft for the full size, but if there are plans floating around for a model already that would be perfect! Thanks

Jared
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Old 04-05-2016, 04:37 PM
  #38
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Chris
Starting to work on a 1/4 Cub, Was starting to create a scale frame in CAD and then saw your post. Are you willing to distribute the frame model? I use Rhino which accepts dwg/dxf/sldprt/sldasm and many more. It would save me a bunch of time and allow me to make accurate fittings and connections for frame sections and attachment points. It's a composite build with wood/aluminum/carbon. Trying to keep it VERY light.
Dorian
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Old 04-07-2016, 10:21 AM
  #39
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I don't know if this would work for you but you can check out what McMaster Carr sells..

http://www.mcmaster.com/#standard-metal-tubing/=11vq17g
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Old 08-04-2016, 08:06 PM
  #40
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Hello all,


thank you for your interested in this topic.
I have not been here for quite some time, probably 3 years...
Basically accidentally I got back to this thread after I found my own pictures from this thread on Google.
I saw that not long ago some people wrote PMs and had asked for more information and the plans. I will think about the plans, maybe I will post them here.
More information and lots more pictures you can find here:


http://www.rc-network.de/forum/showt...enen-von-Piper


Sorry not Englisch but Google translate can help and a pic is more than a thousand words.
However...he Piper project is kinda on hold (not really dead), too much problems and things to figure out and not enough time, but here is still hope.


Here are some pictures from the last stage of the project

[ATTACH=CONFIG]2175835[/ATTACH][ATTACH=CONFIG]2175836[/ATTACH]


Finally I started working on the wing in SolidWorks that was basically where the project stopped.

[ATTACH=CONFIG]2175837[/ATTACH][ATTACH=CONFIG]2175838[/ATTACH]

https://www.youtube.com/watch?v=bByjRlQcJ7s


Thanks
Chris




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Old 02-17-2017, 08:52 AM
  #41
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Hello, can you share your 3d model?cad、SolidWorks、pdf?my E-mail:xianfangdong@gmail.com
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Old 04-19-2017, 04:40 PM
  #42
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only 1 post and you already want my CAD files ...
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