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Thread: New to Solidworks questions and future plans of dressmaking a plane

  1. #1

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    New to Solidworks questions and future plans of dressmaking a plane

    Hi everyone.

    i thought rather then ask questions first...ill state my goals and then ask questions

    What follows is an experiment with an experimental plane....if this has been tried before, please let me know of it's success/failure..

    The 4 place all aluminum CH640 has been discontinued due to lack of sales. What I would like to do is build the Ch640 plane to modern industry standards like Vans aircraft/Zenair does with match hole construction, but doing so with a fusion of CNC precision merged with old school bandsaw, disk sander, router table and sweat...

    For better or worse match hole construction is the industry standard and what the customer expects to see when they open the box.

    The CH640 plans need a freshening up, since the plane can be scratch built a lot of builder frustration can be eliminated if the plans were updated. For a more familiar reference sort of like scratch building a RV-6... it can be done but the plans are first generation

    The 4 place CH640 is the experimental version of the certified 2 place Alarus. The Alarus is beloved by flight schools for training. It's a shame to see a good design fade away.....

    If this works out, make my efforts available to Zenair/Zenith to share with other builders of this plane

    Im thinking that 3 technologies merged could create an easy way to make home brew matched hole construction and give new life to some very good older plane designs. Making them easier to build and assemble at a budget price

    1-design the plane in solidworks, all holes and parts marked out
    2-print out templates of all parts that can be glued to wood or metal
    3-builder cuts/drills/sands the parts as close to the lines as possible

    -the use of vellum(plastic paper) to print on as it does not distort and holds its shape much better then paper and can be re-used

    -use of very accurate printers like the Hewlett Packard page wide...create CNC accurate printed templates


    the experiment here is to see if you hand form an aluminum rib over a hand made wood former....will the holes in the ruder skin line up with the pre-drilled holes in the ribs....I think if you are careful in your creation of your tooling...they will

    here is the plan...build the CH640 rudder in Solidworks as proof of concept. All rivet holes pre located like Vans/zenith does.

    build the form blocks from templates, cut out and glued to the wood..if careful, a form block could be made to machine shop level accuracy

    Then take the vellum print out of the rudder skin rivet pattern, spray tack it to an aluminum sheet and drill the pilot holes for the rivets through the metal.

    peel the vellum off the metal and voila...you have just match hole drilled your rudder skin

    another interesting thing is the vellum is very tough...if this works you could put 4 or 5 wing skin drill patterns on one vellum print in different colors ...so you re-use the print to do the hole patterns on many different wing/rudder/elevator skins. The spray glue can be wiped off the vellum with a solvent and brought back to new


    so now for the questions

    has anyone done a how to sheet metal video on aluminum aircraft building with Solidworks ( in particular making a part like a flap or aileron) I'm learning Solidworks and there are plenty videos but not much on actual aircraft construction . Most videos are RC plane type or mock ups that don't go into the nitty gritty of real aluminum plane construction.
    I watched the EAA Webinar- Exploring the Zenith CH750 Cruzer Design in SOLIDWORKS. They showed great parts but not how they get designed in Solidworks unfortunately.

    Im still learning Solidworks and this has me stumped at the moment..how do you shape a rudder skin over your ribs and spar assembly? I know how to create the skin but not how to radius/bend it over ribs. If someone could direct me what tool or procedure you follow to do that

    that's it for now, more questions to follow.

    thanks

    Michael
    Last edited by North_roll; 06-19-2020 at 06:11 PM.

  2. #2
    SOLIDWORKS Support Volunteer Jeffrey Meyer's Avatar
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    Quote Originally Posted by North_roll View Post
    im still learning Solidworks and this has me stumped at the moment..how do you shape a rudder skin over your ribs and spar assembly? I know how to create the skin but not how to radius/bend it over ribs. If someone could direct me what tool or procedure you follow to do that.
    Hi Michael
    I'm not familiar with the CH750 geometry but I would guess that the sheet metal skin that you are looking for is curved in one direction ONLY, and therefore you can reproduce the skin in SW using a lofted surface (or solid) between two (only two) profiles represented by the ribs and spars. I'm assuming that the spar segments between the ribs are straight lines - otherwise the skin has multiple curvature directions - a completely different kettle of fish.
    Hope I understood your problem correctly.
    Jeffrey

  3. #3

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    Quote Originally Posted by Jeffrey Meyer View Post
    Hi Michael
    I'm not familiar with the CH750 geometry but I would guess that the sheet metal skin that you are looking for is curved in one direction ONLY, and therefore you can reproduce the skin in SW using a lofted surface (or solid) between two (only two) profiles represented by the ribs and spars. I'm assuming that the spar segments between the ribs are straight lines - otherwise the skin has multiple curvature directions - a completely different kettle of fish.
    Hope I understood your problem correctly.
    Jeffrey
    Thank you for the tips, the rudder design is pretty standard as you describe

    im binge watching YouTube Solidworks videos, getting pointed in the right direction is a great help. Ive also started explore the Solidworks tutorials on thier forums.

    thanks
    Michael

  4. #4
    cwilliamrose's Avatar
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    IMHO you have no prayer of getting the holes to line up. If the parts were produced in a factory with hard tooling then you could do much better but no matter what the CAD models tell you the small differences between the real parts and the CAD models will prevent this from working as you would like it to. I'm sure Vans has it down to a science as much as it can be and I suspect any CAD models of the parts are tweaked after the tooling is made to produce proper mating parts. The point is the 3D CAD world cannot reflect reality in every case and adding hand built parts to the mix only makes this worse. Match drilling on assembly is the only way unless you supply a kit as complete as Vans' and do the work involved on the front end so the customer has a fairly easy job when the kit arrives.

  5. #5

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    I’m thinking positive but everything you post could be true...

    since im scratch building it anyways I thought why not try it out on the rudder and see what happens...

    so plan B is to try doing pre punched skins only... if complete match hole construction is a fail....mark the ribs and spars with marker lines down the center lines, a lot like scratch builders do now

    below are 2 plans sheets I did up...(on paper as a test the final templates will be printed on plastic vellum) one for the rudder formers and the other for the wing formers. Using software like solidworks once you are a little familiar with the software, I created those sheets in 30 minutes for the rudder and an hour for the wing. Doubled checked the printed dimensions and they match the plans...

    to be honest I don’t even know what I’m doing... just watched a few YouTube videos and stayed in a holiday in last night ... but the power of cad software is addictive... being able to make accurate templates... it’s just plain cool that those are machine shop accurate cad drawings. Created by a mere mortal.....Solidworks truly is the fire of Prometheus( ok I'll calm down on the theatrics now)

    The photos might be fuzzy due to site size restrictions...but on my end they are razor sharp....the edge of the part is the actual dimensions...cut and sand to the line and you are on the money....I can't tell you how cool it is to drop a caliper onto paper and see plans dimensions come to life.

    once complete those files could save a builder many hours of pencil and paper work drawing on the wood... now you just cut it out and glue it on and start cutting

    even if the master plan is a fail... the pre designed parts will aid and help new scratch builders since the CH640 plans have no templates just dimensions
    As it is right now builders have to re create the wheel each time they build from the plans


    Michael
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    Last edited by North_roll; 06-19-2020 at 06:54 PM.

  6. #6
    cwilliamrose's Avatar
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    Not a bad experiment, please let us know what happens.

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    Making form blocks for sheet metal is a weird science, especially if it bends in more than one direction, like most ribs do. Bend allowance and spring-back, among other considerations, are pretty much trial and error when it comes to complex shapes. And then bending the aluminum around the form block is another difficult job if done by hand. I'm not familiar with Solidworks but CREO (Pro-Engineer) has a good sheet metal program that creates flat patterns and form tooling fairly easily, but I haven't used it much. You might also consider a CNC router table like this cheap one: https://www.youtube.com/watch?v=jjdXpp77MdU
    The router could cut out the flat sheet metal parts for you with much more precision than printed templates. They run in price from this one and on up in the millions It's a pretty good investment for what you want to accomplish.

  8. #8

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    Quote Originally Posted by bechis1 View Post
    Making form blocks for sheet metal is a weird science, especially if it bends in more than one direction, like most ribs do. Bend allowance and spring-back, among other considerations, are pretty much trial and error when it comes to complex shapes. And then bending the aluminum around the form block is another difficult job if done by hand. I'm not familiar with Solidworks but CREO (Pro-Engineer) has a good sheet metal program that creates flat patterns and form tooling fairly easily, but I haven't used it much. You might also consider a CNC router table like this cheap one: https://www.youtube.com/watch?v=jjdXpp77MdU
    The router could cut out the flat sheet metal parts for you with much more precision than printed templates. They run in price from this one and on up in the millions It's a pretty good investment for what you want to accomplish.
    Thanks for the info...took a quick peek at the video....looks very interesting...ill watch this tonight..

    and ill check out the software....



    thanks

    Michael

  9. #9

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    Do a search on “SolidWorks ruled surface”. You are trying to define a developable surface, which is a type of ruled surface. That is, a surface with a single degree of curvature. Think plywood, which can be bent in only one direction. SolidWorks can let you, in effect, peel a surface from off a solid. That peeled surface will lay flat on your sheet of aluminum for cutting and drilling.

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