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Seagull T34C reborn

  • This topic has 7 replies, 3 voices, and was last updated March 27, 2020 at 3:06 pm by 247rememberme. This post has been viewed 215 times
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    • #5746
      Paul Phelps
      Participant


      The original T34C was a trike u/c USN trainer and Seagull models produced a grey camo version which I inherited from Dave, stripped the frame, extended the nose and converted it into a tail dragger, Steerable tail wheel with mini oleo. Fixed undercarriage with double oleos.  All new servos, electrics motor and esc and recovered in my own scheme.   The canopy and rear scuttle was modified to make use of the good bits of the original broken canopy and the wing tips squared off. The completed model is 1900mm wingspan 54.70dm2  4650gms = 85gms/dm2. original design loading of 5.1kg for the seagull plane = 93gms/dm2.  CG 120mm back from wing joint as per original manual Power required =1275w to 1535w .( 125to 150w/lb)warbird to fully aerobatic) using Turnigy SK3 5055 430kv motor rated at 1750w max, 70a max 5s to 8s.

      I used Aerostar 80amp esc with 5amp bec ( reversing motor which might be required now the field is rolled) 15×10 tgs electric prop FFll Throttle 1425W 60amp on  fully charged 6s battery.   3/4T 941w 40a.   2/3T 735w 31a.   1/2T 460w 18a.    1/4T 204w 8a.. wing loading 88.5gms/dm2 . using 6 cell zippy compact 4500 40c 730gms pack.  6 mins plus flight time.   First four flights were done Thursday afternoon 19th March after everybody had gone.   Plane lifted off at 2/3  throttle, cruises around at half throttle, flies like a big low wing trainer, lands on cut throttle, floats on in, no nose overs with the large 4.5 inch tyres.Small amount of up elevator and right aileron required on maiden flight, cg could go back a bit but its fine for now. No balooning on flaps down as I added a touch of down elevator mix prior to maiden. All in all well pleased.

      Paul Phelps

      • This topic was modified 2 months, 1 week ago by Martin Lynn.
      • This topic was modified 2 months, 1 week ago by Martin Lynn.
    • #5748
      Paul Phelps
      Participant

      Dont know what happened here but the text is not as I submitted with strange references to.

      Paul

      • This reply was modified 2 months, 1 week ago by Martin Lynn.
    • #5751
      Paul Phelps
      Participant

      photo of original  Grey T34C model for reference

    • #5752
      Brian Merton
      Participant

      Paul, just read the setup used on the rebuild. I don’t wish to put a downer on it but I have had 3 of those same ESC’s fail on me, on the ground (2 of them) the other mid air. Speaking to HK they had delivery of a couple of thousand of these with faulty mosfets but they couldn’t say which were good or bad. This was several months ago so if it’s a new one you should be ok.

    • #5753
      Paul Phelps
      Participant

      Thanks Brian I will swap for Hobbywing anyway just to be safe

    • #5754
      247rememberme
      Keymaster

      You should feel really proud with yourself Paul,you have done a fantastic job and it looks fabulous.

      Another cautionary note on the electrics,I wouldn`t be happy using a 5A BEC with this and would use at least 10A or bigger.

    • #5755
      Paul Phelps
      Participant

      thanks 247,I checked out each servo tech specs before use and calculated load on each control surface using know calculator before selection of servos.  I used 75mph air speed for main controls, 45mph for flaps then used 2/3 kgf stall torque value before selecting each servo for safety margin.    Each servo draws 220ma max   HK939MG i.e. metal gear analogue servos, 2.5kgf 4.8v.   So  2x aileron, 2x flap, 2x elevator, 1x rudder , no retracts so no overload danger from sticking retract servos, so say 2amp max if I use em all at once which is unlikely, more likely to use 4 at once i.e 1amp max, double that is still 2amp.  RX & ESC powered up, no load draw whilst operating all servos on static model tested out at  0.73amps.  So in flight under load unlikely to exceed 2.5 to 3 amp so I am ok with 5amp bec on this particular model.

    • #5760
      247rememberme
      Keymaster

      I know in theory everything is well under the 5A BUT having seen first hand in practice it not go so well I just thought I`d mention it.

      I am looking forward to seeing the model for real 😀

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