Antonov AN2

Discussion in 'Scratchbuilding!' started by quorneng, Dec 20, 2018.

  1. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    I suppose a had better come clean - I am building one but hopefully true scale and largely in 3 mm Depron!
    For another project (now on hold!) I bought a 10x8.2 four blade prop and a suitable low kV motor to drive it on a 3s. Just about perfect for an AN2. ;)
    The cowling on the AN2 is circular so ideal to 3D print and plenty big enough to really 'see' the ASh -62 inside it so it seemed logical to print a complete near scale 'engine' as well.
    4Blade.JPG
    Not really a time effective exercise but I find solving the printing issues absorbing. Although the engine looks fairly solid it is surprisingly light being entirely hollow (even the push rods!) with a print thickness of only 0.3 mm.
    The cowling itself is fairly straight forward. A rear part that also acts as the motor mount and a simple circular front section that covers the 3D printed 'engine'.
    Needless to say the Ash-62 is much more complex comprising of 74 individual components that have to be glued together like a plastic kit!
    This leads to the rather bizarre situation of creating and printing the cowling and than scaling the air frame to match it! It looks like the AN 2 will have a span of 44" (1120 mm).

    The intention is its 'stocky' fuselage will be a 3 mm Depron monocoque skin over printed formers with no other reinforcing.
    The wings will be de-mountable. A although its wing span is not that large a 'one piece' biplane takes up quite a bit of space!
    We shall see.
     
  2. That's awesome, 72 pieces holy crap, you better not drill it. ;) The scale on mine this last build was at 120 % from the original and now has a 42" ws and not to bad fitting into the back seat still. :)
     
  3. Skis are finished and wire bent but not going on until we get more snow. NOT that I want any. The black painted ones are for the P-40. built these the same except 12mm wider .

    2018_1220_131734_001.JPG

    Ooops, wrong thread, sorry
     
    Sterling101, JTiger and andy_downs like this.
  4. Did you pick up and have you used the 1mm Depron and some of that Selitac foam from RC Foam?
     
    Sterling101, JTiger and andy_downs like this.
  5. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    I can only get 2, 3 or 6 mm Depron from a local Model Shop both grey and white.
    I prefer white as it is slightly 'stiffer' and with sufficient support it provides a useful useful skin that, in the right application, can be strong and rigid enough to carry all the flight loads with no reinforcement.
    This is built from just 2 mm Depron - no balsa or carbon anywhere.
    26" span but 62" long. Even the 55 mm EDF is simply glued onto the 2 mm Depron inlet tube.
    Avatar1.jpg
    You don't have to be crazy to do such a thing but it helps.;)
    It flies well too via a hand launch and a belly land.
     
  6. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    The next printing exercise is to create the fuselage formers.
    To give a reasonable degree of support to the 3 mm Depron skin there are 10 in total.
    TenFormers.JPG
    One problem of doing it like this is there is no adjustment possible to make it fit. It has to be exactly right so you do tend to end up with quite a few in the bin!
    SixScrap.JPG
    At least they are light so not that much filament is wasted.
     
  7. Keep the pictures coming. :)
     
    Sterling101 likes this.
  8. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Ther next stage is to fix all the formers in.
    The AN2 has quite a substantial area of flat sides so this was marked out on the tile printed plan and matching 3mm Depron sides cut out and the foremer position marked on the inside surface.
    Finally the position of the flat area was transferred to each former.
    The first 3 formers added and the tail brought together
    FirstForms.JPG The remaining formers added. AllForms.JPG
    It actually results in a very 'conventional' form of construction but using 3D printing and Depron.;)
     
  9. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Whilst adding more fuselage skin planking I realised I had got the dimensions of the 3rd form wrong.
    However UHU POR has a useful attribute - it takes many days or even weeks to reach full strength so with a bit of care it was possible to completely remove the offending former and set about printing another.
    At the same time I organised the 'external' undercarriage mount for the spring unit. UCmount.jpg
    My version
    UCmounting.JPG
    All the undercarriage links will be 'printed' parts as well.
     
  10. bogusbandit56

    bogusbandit56 Top Gun

    Posts:
    8,756
    Likes:
    19,744
    Points:
    133
     
    Wildthing and andy_downs like this.
  11. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Not that much gets done over the Christmas break.
    With a bit more of the fuselage skin complete I temporarily mounted the ASh-62 on the nose of the fuselage and raised it up to about the correct angle to check the prop clearance.
    PropClear1.JPG It is not that big but it still has quite a 'presence'.
    Next job is to complete the fuselage skin around the wing mounts to ensure they are a good fit.
     
    Last edited: Dec 26, 2018
  12. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Slow going but at last the fuselage planking is complete.
    PlankCmplt.JPG
    Note the strips of masking tape used to hold the plank in place until the glue sets.
    A view down the fuselage - seriously empty!
    Inside.JPG
    The cockpit area (it will also hold the battery and radio) will have a complete internal skin to maintain adequate torsional rigidity.
    As a result the fuselage will have almost nothing in it with just two servo (rudder and elevator) right at the tail. The only other items will be servo leads!
     
  13. Looks awesome, looking at the first picture that looks like you are coming up with some fancy vertical layout. :)
    My AN2 is empty down the inside, easily will fit 16 passengers. :D :D
     
  14. rodrigo

    rodrigo Top Gun

    Posts:
    2,081
    Likes:
    340
    Points:
    103
    Beautiful work Quornerg!
    The motor is absolutely amazing and the fuselage geometry is perfect.
    Foam+ 3D printing is a perfect mix lightweight and strong the first and geometry perfection and replication for the second.
    Just I have doubts about strength on the main gear arms. I use the classic piano wire combined with 3d printed nodes (and diy springs) on my 150cm Pilatus Porter and works amazing even on hard landing with a AUW of 1,3kg.
     
    JTiger, Sterling101 and andy_downs like this.
  15. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    rodrigo
    You may be right but my AN2 will be significantly lighter and coupled with long stroke soft springing the intention is the undercarriage will break off before tearing out the fuselage mounting points.
     
  16. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    With the lower wing centre section glued in all the undercarriage mounting points are available so some detail CAD design and we have a 'working' undercarriage.
    UClegs1.JPG
    All printed so the only metal bits will be the stub axles and the springs!
    The spring units do not have springs in them yet (on order) but they should give about 25 mm of suspension travel.
    Wheel hubs next. ;)
     
  17. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Now sitting on its wheels.
    UCwheels.JPG
    Temporary rather too stiff springs are fitted. A set of softer springs are on order.
    Tail wheel next.
     
  18. Wow, no double wow. :) That suspension looks great, are you using just standard pla?
     
    Sterling101 and andy_downs like this.
  19. quorneng

    quorneng Ace Pilot

    Posts:
    613
    Likes:
    1,443
    Points:
    93
    Wildthing
    Yes standard PLA but each struts is carefully designed to be strong enough but will break at the pin joint before pulling out of the fuselage - I hope!
    As long as it does I can always print replacements.
    I am hoping the soft long travel suspension will help.
     
    Sterling101, andy_downs and Wildthing like this.
  20. Somehow I know it will work for you. :)
     
Similar Threads
Forum Title Date
Scratchbuilding! Antonov AN-2 Biplane Design Dec 3, 2018
Scratchbuilding! Antonov 225 Apr 14, 2010

Share This Page

string(1) "1"