My Homebuilt RC Micro Paper Se5a

Discussion in 'RC Aircraft & Watercraft' started by liftline, Jun 18, 2011.

  1. liftline

    liftline Member

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    It's a lot easier to make things look photogenic the 2nd time around.

    I still need to enlarge the rudder to achieve both greater realism and rudder authority. The prop wash is simply incredible with these high rpm motors - I need full rudder to counteract it at roll off. Hand launch is a must without ailerons I fear. I'll add 'em later, but it's just too much engineering to pack all that in at this stage.

    The weather is just terrible this year, but I'll charge up some lipos and keep everything on standby. Might need to handcuff my vidographer to a solid object - I'd sure like a good quality movie.

    I'll try and at least get some shots of the prop & control surfaces doing their thing.
  2. liftline

    liftline Member

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  3. schorhr

    schorhr Member

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    You could go 35 MHz (as those are compatible with different brands) and get a cheap ~27$ transmitter from ebay, and a (expensive) micro reciever. I'dd still recomend to modify (a second) cheap-o reciever for your existing transmitter and strip it down (desoldering the pin connectors and everything should get it into a similar weight category)...

    Also, at least for indoors, there are some clever micro infrared radio sets for micro planes, but their use outdoors is rather limited. Those can weigh under 1g easily though.
  4. liftline

    liftline Member

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    No magic bullets eh? Yet anyway - the technology is evolving pretty fast.

    I can lose 3 g by just removing the case, that should compensate for one more servo and some push rod.

    I'm putting in an order for batteries, more FLySky receivers and a Z bend tool.
  5. schorhr

    schorhr Member

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    Good :) The micro stuff gets expensive quickly, even with cheap china direct order...
    How does it perform with the current weight?
  6. redwolf28386

    redwolf28386 Member

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    Great project! After you get her flying , how about posting a video of her airborne?
  7. liftline

    liftline Member

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    I haven't added the additional aileron servo yet, and small changes I made to the latest version haven't changed weight measurably - still 42.5 g. Still too hot to taxi test in the hall! Accelerates very quickly once you goose the throttle past idle.

    Rained most of the day yesterday, it's supposed to rain all week :cry:

    If my brother remembers to get me his digital camera I'll video a walk around while I wait for the weather to break. We've got to have a drought sometime around here.
  8. Zathros

    Zathros Guest

    The P-Factor in those motors are incredible. My electric store bought plane has a V-tail (Rudddervators) so it is not too much of a problem, but it is simple in that there are no ailerons. it flies so well, it does not seem to need them, thought it is really not acrobatic. I thought of gutting in, but it would not be worth it. I am tempted to buy one of those really big Styrofoam, B-52 looking gliders the kids use, and make a lumbering R/C out of it. 2 electric motors would make it fly well enough and the big wings would allow a lot of loading.
  9. liftline

    liftline Member

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  10. Zathros

    Zathros Guest

    Being a vintage audio tube amp/preamp collector, I cringed at the last statement, but then reality set in. Do you think you could post your supplier for the micro servers etc. that you are using? I also am designing an A90 Ekranoplan and am very tempted to make a R/C version of it, or of the smaller ESKA, both which eventually will be released in paper. (the Rot of the Rudder on the A90 is off, I know and am working on it:mrgreen:).

    Attached Files:

  11. liftline

    liftline Member

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    Beautiful - what CAD are you using? How do you flatten your 3D forms to patterns? I still haven't found an inexpensive CAD that really helps me much. So, I still design by successive cross sections which I connect with linear shot lines which I split into facets which I reconnect on a 2-D surface. It's all automated (my own programs), I just digitize points and print the patterns from vector files. I've had to learn a lot of conical geometry over the years. Every airplane I design is intended to be air worthy and a fairly quick build. If you look at my other thread on this forum you can see examples of my work - including a 12' by 6' SAAB Gripen fighter jet, which is a display model exception to my rules.


    I have purchased from HobbyKing.com and HobbyPartz.com and have had good experiences with both. Shipping can take a while, but the overall saving are impressive and the quality of the parts has been good so far.
  12. Zathros

    Zathros Guest

    I use Rhino 4.0. I was a machinist for 16 years (among too many other trades) and programmed 4 axis CNC machines, and made all the fixtures and tooling for these machines at Sikorsky Aircraft. In Rhino4, you can make the profiles, which are called "Rails" and connect them with a line, or curve, which would in that operation be called a "Profile curve", and then you would use the "Run 2 Rails" Command and create the part. If you use a straight line between the profile curve, you can then "unroll" the developable surface. It is important to keep this in mind because a curve as a profile curve could not be unrolled as it would be a compound curve. I have attached the nose of the craft, unfolded, not rendered, to give an idea of what is going on. The nose section is doubled, this model's nose section will take some patience to make, but all parts fit.. The picture is a practice fit made of the unrolled pieces you see. They all fit. I make it practice to 'unroll' every part before I move forward.


    A fully working version of Rhino4 can be downloaded. After 30 saves, it loses the ability to save but still can model. It is a great way to learn the software. If you are a student (or know someone who is, hint, hint) you can get it for a fraction of the price! Really really cheap.:curse:twisted:

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  13. liftline

    liftline Member

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    Very fine! We get to the same pattern place (yours look very familiar) but by very different software means.

    Go here:
    http://www.zealot.com/forum/showthread.php?t=169146&page=3

    Traditional card modeingl approaches don't work well for me. I tried to fly commercial card stock kits as a kid, but found them to heavy, too fragile and too labor intensive to risk. So, I had to innovate on my own. No home computers back then - I actually made a lot of pretty decent looking and reasonably functional models entirely freehand, using a ruler, a scissors and a bottle of glue. Crazy really, but I didn't know any better and I stumbled upon a lot of tricks I still use. I really learned a lot about how paper works.


    I use very light weight paper and pay a lot of attention to internal structure. At the same time work hard to keep construction simple, quick and easy. Most of my designs resemble modern nuke subs - you build each fuselage element separately and pop them together at final assembly.


    My father ran a small engineering business specializing in one-off wind tunnel models for the big aviation companies. He also did some radar x-section models for the early stealth AC, but I never saw any of those (double secret highly classified). My brother is a 1st gen CAD/CAM engineer and he brought the firm up to speed on this technology. Tough way to make money, the new technology made everything very fast, but lowered profit margins. It displaced a lot of incredibly skilled old school machinists.

    I'll have to look at Rhino. I've tried the freeware SketchUp and was impressed, but the unfolding tools are a pay add on.


    My Se5a is my first RC attempt. It's a 40% scale-up of a model I designed in 2003, with roots that go back to about 1999. I chose it because the form is fairly simple, the insides are roomy, and I know it glides well. The biplane config gives a lot of wing area and makes for a lot of strength without much structure - but those wings are internally braced! Enough details to make it interesting, but that undercarriage is going to get rebuilt a lot I'll wager.

    Cloudy today, still calling for rain.
  14. Zathros

    Zathros Guest

    Very cool, thanks for pointing out the links. We better start making more stuff in this country (USA) or we are going to find ourselves in a whole lot of trouble. I have a machine shop in my barn. When my Subaru needed an exhaust, I went out and purchased some pipe and in about 45 minutes, welded up an exhaust. It cost me around $50 bucks, as opposed to the $800 they wanted, and that was from the catalytic (not included) to the back!!
  15. liftline

    liftline Member

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    Seems like you are one of those old school machinists, hopefully not displaced. I too have had a multidisciplinary career, but can't say I've ever built my own exhaust!
  16. Zathros

    Zathros Guest

    I was disabled at work. I kept working though. By the time I had to stop, I had lost my benefits because by working, Proved that I was not disabled, though I had to stop, because i was disabled. I have had close $500,000 worth of surgery, and I can walked again. I am uninsurable, do not collect a dime from anyone, because, again, I kept working, so I couldn't be disabled right? Old story, mentally past it, physically living with it.

    I am by necessity, the cheapest person I know. As I have been disenfranchised, I barter, work under the table when I can (welding lawn equipment, or making parts for "normal" people and generally scrape by. A number of business really tried to hire me but could not get insurance, worker's comp, or any other kind, and my doctors will not release me for liability reasons. If I work for 2 years straight, then I can try to claim Social Security again, which will of course be denied, because I would have just worked, and Social Security has me classified as being 100% disabled, officially. It is really complicated, spent many years in court and was handed a decision that most lawyers don't understand.

    Got sidetracked, I have trouble riding a bicycle, so I figured I would try and buy a recumbent trike,until I looked at the price. So, I made one. In my prime, this would have been a weekend project, but it took me a month. I have attached a picture. Disc front brakes, rear suspension, air shock. Cruises easily at around 20 miles an hour. My own design. It is made out of .050" wall thickness exhaust pipe stock (mild steel). Canondale Bicycle Corporation donated to me around $3000 dollars worth of accessory components to help me with my projects. Very very nice of them! My recumbent bicycle only weighted 10 ounces more than their aluminum one, mine was steel! They were impressed, then handed me boxes of parts. I have attached a pic of the trike. 24 Speeds. Your arms are straight down and if the trike tips on a sharp turn, you automatically lean into the turn, pulling that side down,very functional. Still very hard on my lower Spine though, unfortunately. The Ackerman and castor and camber of the wheels was calculated out on Rhino4. The steering knuckles are extremely heavy duty Heim Joints and I machined aluminum hubs for the plastic wheels, pressed in road worth bearings and mounted the disc brakes to them. All parts were machined from square stock T6061 aluminum and the only ready made components are hardware, bicycle parts, such as derailleurs, chains, sprockets, etc.. Frame was fit using a tubing notcher and Mig welded by me. It also, (obviously, by it's Rue Goldberg appearance), designed using the "form follows function" methodology:p

    Next project will be a Velomobile, with electric assist( actually, pedal assist, I plan to circumvent the law!).:twisted:

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  17. liftline

    liftline Member

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    Yep, old school machinist! Beautiful piece of engineering & craftsmanship. Weighs in at? 20 mph is pretty impressive, wonder what you could do with a fairing?

    I'm a bit of cyclist myself, used to triathlon (sprints mostly), I usually just run these days in large part because I need to change pretty much every bearing in my old machine and don't have the time or work space. I still like the feel of a steel bike and if the tubes are thin they are still pretty light. They last too, and if you crash 'em, you can still salvage the frame.
  18. Zathros

    Zathros Guest

    I feel like I am really ruining your thread, I am so sorry. The trike weight has escaped my mind. It is comparable in weight of any commercially available trike, probably a little lighter. The seat came off of a recumbent bicycle and the seat framing is made of aluminum. The mesh for the seat came from a fabric store, the same stuff used of furniture, quite strong. Aluminum bicycles are actually too rigid (Canondale's anyways) The large diameter of the thin walled tubes does this. I have a friend, Frank Strnad, that makes incredible bicycles. He uses .010" thickness frames and does not believe in aluminum for his custom bicycles. I have not seen him for a while, as I moved from Ridgefield (snooty little town) but he is an incredible person. He sold me his Miller Econotig for $300 bucks, it is virtually brand new!
    This is one of his bikes. It costs $6,149 dollars, all are custom fit to the rider. I put a link to his website. I could never afford anything he makes. He really liked my trike and recumbent bike, from him, I was I felt really honored. People come from all over the world to buy his bikes. I thought you might find this interesting, hand made bikes, he makes the frames, all of them, personally, from scratch!




    http://www.ridgefieldcyclesport.com/pricing.html
  19. liftline

    liftline Member

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    I feel like I am really ruining your thread

    If it gets too messy I'll start another. I have a life outside of paper RC :cool:, always interested what else fellow hobbyists do.


    Every one of those bikes is worth more than my car! I was always the only guy in the triath without an aero wheel on the back. Most of the local events boil down to the run anyhow...which is what I do best.
  20. Zathros

    Zathros Guest

    Me too! He asked me if I knew anyone who would be interested in his Miller Tig welder and he was selling it for $900 dollars, he only built 60 bikes with it (not much time at all on this machine), it included the foot pedal and all the accessories. A week later, I asked him if he had any takers and I mentioned if I had the money, I would buy it, he looks at me, somewhat bewildered, and says in his deep Czech accent, "John, for you I would only want $300 dollars", I drove to the ATM machine and back in around 10 seconds flat!! Frank Strnad is a very kind and gentle person. You could play catch with his bikes, they are that light. He even does the painting and finishing work personally. He sells every bike he makes too. I did not realize the picture did not show of the Strnad bike, I just copied the one on is website. I could never justify buying a bicycle like that but I am happy for Frank that others do. I would have to get around 120 horsepower and have Suzuki 1250 Bandit written on the side, I will have to do with my GSX 750ES for now..

    My trike weighs in at around 30 lbs, a little less. It is a lot, but not that bad for a recumbent trike.

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