Gartt Gt 700 Dfc (same As Assault) Stretched To 800

Discussion in 'HobyKing' started by utrinque, Oct 18, 2014.

By utrinque on Oct 18, 2014 at 5:35 PM
  1. utrinque

    utrinque Well-Known Member

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    I fly this beast since January. In ten months I crashed it only once. It prooved to be very reliable heli with some Align parts. If you type in Google "Gartt 800" you will find whole story of this project. Now I can do rainbows and tic-tocs with this 800.

    I am not the only one. My friend Benji after reading my thread on Polish forum also built 800 based on Assault 700 kit. He also flown it for months without issues. Actually idea to stretch it to 800 was mine but Benji was first to maiden it with 800mm blades.

    Idea was simple. Get cheap frame. Put $30 Align stretch kit including longer boom, TT and tail push rod.

    I am using 4.2kW Gartt 700 motor and it is strong enough. Lately Gartt released stronger 4.5kW motor for just $50.

    I was able to get this kit for $175 without canopy directly from Gartt. I ended up with four airframes. Two of them are now 800s and flying, one is flying with 700mm blades and one I keep in the box as a source of spare parts.

    Those who said it is Chinese shiz were wrong. Actually NMB bearings used by Gartt are excellent.

    To make this clone kit as good as Align you have to replace only swash plate and main gear.

    In 800 I have more Align parts for piece of mind.

    All is described in my earlier thread on HF. There you'll find photos, videos, whole story in details. In want to move my story from HF to HeliGods because I do appreciate your great attitude and open mindness.

    Actually my thread on HF was second most often viewed thread in 800 electric subforum. Not many pilots wrote in my thread but many were following my story.

    Greetings from Poland to all HeliGods "community".

    I do not have any issues with this bird so probably this thread will be quite silent. If anything happens I will update and share my thoughts. I plan to fly it again tomorrow. Today weather is not nice. I love to fly it in strong winds but rain, cloudy and cold weather make me hesitate. Many hundreds of flights it already survived. I am quite confident it will survive next year.

    My friend Benji with his 800:


    Off-topic:
    Interesting interview with cosmologist:
    http://wunc.org/post/meet-laura-mersini-houghton
    She is exceptional. Worth to listen to this interview.
     
    Last edited: May 6, 2015

Comments

Discussion in 'HobyKing' started by utrinque, Oct 18, 2014.

    1. utrinque

      utrinque Well-Known Member

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      I was flying 800 and 700 today. My helis are still in perfect condition.

      I like this video. It confirms Assault is good.
       
      Last edited: Nov 10, 2014
    2. smakmeharder

      smakmeharder Administrator

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      Nice night flying Utrinque!! well done!
       
    3. utrinque

      utrinque Well-Known Member

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      It is not my Assault. I did not put LEDs on my Assaults yet.

      Anyway I increased throttle curve on my 700 today and it is faster than ever before. I like this heli. 800 is my favourite.

      I fly like this:


      I did not record new videos since April. Now I fly higher RPMs but I still enjoy low RPMs in first idle up. They help me keep motor temperature relatively low. YEP freewheel is awesome and lets me fly at 50% throttle. I have 112/12 gearing and 530kV 4.2kW motor.
       
      Last edited: Nov 11, 2014
    4. Busher

      Busher Member

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      Hi Utrinque

      I'm currently building one of these and would appreciate a point in the right direction for power supplies

      What type of bec or power supply you are using as the YEP 120 hv seems to be opto. Can you recommend a bec ? And if so do you run it at 6s or off both batts at 12s.
      I need a bec as my cyclics are only good for 6v,

      Thanks
       
    5. smakmeharder

      smakmeharder Administrator

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      Hi @Busher @utrinque is the king of the assaults and he will advise you i am sure. But I know the YEPs have a great reputation. Re your BEC what servos are you running? Once you know what current draw to expect you can calculate the correct size BEC. But many people who build a bigger helicopter like to run a separate receiver pack
       
    6. Busher

      Busher Member

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      The servos are as follows,

      Cyclics turnigy 1258tg, 13kg @ 6v
      Tail Hk mi 8.4 kg 0.04 @ 6v 0.03 @ 7.4

      Bought these to try out they seem up to snuff spec wise and the quality looks quite good, no slop in the gears and well built.

      Not sure about the FBL system yet, choices are vbar mini, zyx, ar7000, spirit.
      I'm just planning at the moment which I enjoy very much, when I have the bits I will start my winter project on Boxing Day as my missus has put the heli away for my Xmas present.
       
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    7. utrinque

      utrinque Well-Known Member

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      I use YEPs all around. 120A HV in 700, 180A HV in 800. Keep in mind for smack 160A HV is recommended for 700.

      20A YEP SBEC is OK for 700-800 with HV servos in my 800 and Benji's 800. I power it with 12S lipo, Benji's with one 6S lipo from 12S setup.

      Those servos look good for 700. I use 1266 and 1267 on cyclics. They are rebranded Power HD servos. Mine are slightly stronger I suppose. Keep in mind your are not HV so you need 5-6V BEC and should not use 2 lipo directly.

      Kbar is good gyro. 26$ with free world wide shipment on eBay. ZYX is also not bad. Never failed on me.

      Personally I do not trust TGY Mi servos on tail. TGY-BLS805MG for tail and TGY-BLS815MG for cyclics are my favourite.

      Good luck.
       
      Last edited: May 2, 2015
    8. Busher

      Busher Member

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      Thanks for your help, I have ordered a YEP 20a bec, I will also have a look at the servos.

      Can I ask if you have had a failure of the mi servos in the past ?
       
    9. utrinque

      utrinque Well-Known Member

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      I burned two Mi servos before I realized high timing on ZYX make them very hot. It was my mistake. Anyway I prefer blue TGY servos. They are rebranded KST servos.
       
      Last edited: Dec 11, 2014
    10. utrinque

      utrinque Well-Known Member

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      It took only three weeks (21 days) to sell all 38 Assault 700 kits from Hobbyking European Warehouse. Check this:
      http://rcsearch.info/hobbyking/i64877/

      Keep in mind that Assault was also available from:

      International Warehouse in three variants:
      - Old one which is discontinued:
      http://rcsearch.info/hobbyking/i37562/
      - Updated new one
      - Combo:
      http://rcsearch.ru/hobbyking/i64667/

      US Warehouse

      UK Warehouse

      AUS Warehouse

      Actually they sold hundreds of them already.

      Gartt GT 700 DFC can be ordered:
      - Directly from Gartt
      - From Amazon http://www.amazon.com/®GT700-Helicopter-Torque-Version-Upgraded/dp/B00FGLB3MW
      - on eBay
      - aliexpress
      - www.rcchinamade.com



      Summary of my experience:

      I do recommend replacement of following parts with Align:
      - swash plate - Gartt improved design after I have sent a request. I tested it already and recommend using Align swash. It is around 30$ and will survive most crashes. This one is Align swash broken by RockinRush:
      [​IMG]
      - main gear slant 112T-118T mod 1.0 - I am flying with Gartt main gear on my low weight 700 without issues, but slant main is quieter and can handle hard flying in Trekker
      - front umbrella gears - for piece of mind because it seems to be weakest point of Align design
      - tail slider - my friend Benji is still using Gartt tail slider in his 800 but he reinforced it with Loctite 638, this procedure is not easy because new one is difficult to disassemble and waiting until it has play is not best solution
      - M3 bolts keeping tail grips in place - I do recommend 12.9 hardened bolts - I did not replace mine yet, but one of them broke in flight once
      - optionally tail shaft with umbrella gear - I am using Gartt but Align upgraded this part because old part HN7042 sometimes broke, you will need this part: H70G005XX it contains new hub, old one used also by Gartt will not fit
      - landing gear - Assault has stiff one but fragile, good pilot should have no problems, but Align plastic is stronger
      - thrust bearings in tail grips - are included in Assault kit, but Gartt had 3 radial bearings, they are cheap around $2 if not with Align logo
      - tail supports - I use Gartt parts in my low weight 700s without issues but I recommend. reinforcement with small screw.
      - links and ball links - should be fine for 700, in 800 for piece of mind I use those from Trekker they look stronger

      I use Taranis radio.

      In 800s I do not have problems with:
      - whole frame - main shaft mounts and tail mount are strong enough
      - oryginal NMB bearings and OWB are fine (Align kits hed some problems with OWB which required additional Loctite)
      - DFC heads (till now three of them work great... I am still testing them) - I did not fly very high RPMs. I think with 800mm blades 1800-2000 RPM should be ok for them. One head survived hard crash without scratch
      - main shaft
      - alu servo horns provided with Assault kit - survived 800 hard crash
      - tail cage
      - tail fin
      - rear umbrela gears, tail grips, hub - I use them in 800

      I have replaced tail slider and "buterfly" for piece of mind, someday I will use original Gartt tail slider

      I use YEP 180A HV regulator in 800, YEP 120A HV in 800 and 700, TGY-BLS805MG servos for cyclics and TGY-BLS815MG HV for tail - those servos survived 800 crash,are strong fast, have BL motors and metal gears.

      In 700 I did not experience problems with:
      - tail boom and TT
      - tail push rod after I reglued it
      - tail pushrod mounts
      - skids should be fine for 700

      For 700 I recommend YEP 120A HV, cheap $30 Power HD 1266, 1267 servos, $50 TGY-BLS805MG and TGY-BLS815MG HV (tail).

      Motors:
      - Turnigy 700 Series 530KV Brushless Outrunner Helicopter Motor - I have three of them, 800 can easily fly 102mph with this motor, I keep relatively low RPM,I do prefer lower kV for 800, but YEP can handle low throttle curve (for me they re better than SK3 700)
      - 700 .90 Size 530KV Brushless Outrunner Helicopter Motor $76.35 - I did not fly it.
      - Turnigy HeliDrive SK3 Competition Series - 4962-480kv-560kV - I like those for low weight 700s
      - Benji uses Align 850MX in his 800
      - KDE has 330$ >12kW ; )

      I have few hundreds of flights with 3 Gartt GT 700 DFC kits. Two stretched to 800. I like them.

      Are they good for you? I have no idea. Your call...

      Benji's 800 (idea of stretching to 800 was mine but he was first to dare to maiden it)
      One year later it is still kicking.
      [​IMG]

      One of my 800s:
      [​IMG]


      My favourite video of Assault 700 8.5.2014 Jan Erlebach:
       
      Last edited: Jan 31, 2015
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    11. utrinque

      utrinque Well-Known Member

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      Part of my fleet 0:18-0:20; 0:38-0:46:

       
    12. Busher

      Busher Member

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      Utrinque,

      Can you tell me about your build of the gartt, I'm about to start mine soon but most of the kit is already assembled, did you take all the parts apart and rebuild them with loctite or did you find this was unnecessary as the parts were already loctited.

      Thanks
       
    13. utrinque

      utrinque Well-Known Member

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      I did not disassemble DFC head. It was not necessary. Out of three heads actually only one screw mounting blade grip was removed to check if thrust bearing is lubricated. It was. You need to heat up screw first to be able to unscrew it.

      I did disassemble all other parts. Actually it was very fast process. 2-3 hours.

      General rule DO NOT use to much loctite. NEVER use force to tighten screws provided. It will weaken screw considerably. Otherwise screws provided with this kit are OK.

      I think bearings provided in this kit NMB are very good, I do not know if better than bearings Align provides. I never had problems with OWB. Benji also likes those bearings.

      If you want to fly it hard consider my recommendations I provided in previous posts. There are weak points:
      - swash
      - main gear
      - boom supports need to be glued again and preferably using thin bolts to fix them firmly.
      - use Trekker 800 plastic ball links and push rods for safety headroom

      Stock kit is flyable but those upgrades will provide more solid and capable heli.

      One more thing. If you start from zero consider cheap Align DFC combo. Count twice. Assault with upgrades and good electronics can be MORE expensive than Align Combo.

      Use small screw to fix boom in plastic boom cage in the frame. Hole is there.

      If it is your first 700/800 ask experienced pilot to help you setup gyro and check your build. It can save you a lot of trouble.

      Start with relatively low RPM and angles on cyclics and collective first. I personally like to use a lot of expo with maximal possible angles.

      After few flights if motor and ESC do not heat excessively you can increase RPM and angles to your taste.

      Keep in mind Align landing gear is stronger. Get it if you expect any hard landings. It can save your expensive blades.

      Do not hurry. Good luck!
       
    14. Busher

      Busher Member

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      Thanks that's a great help, looks like I'm going to enjoy the build, I have the kit and the gear to build it now, and all I need now is some modelling time
       
    15. smakmeharder

      smakmeharder Administrator

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      Thank You @utrinque that is a very imfomative and helpful post!
       
    16. utrinque

      utrinque Well-Known Member

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      I have started threads about Gartt stretch on Polish forum epheli and on Helifreak. I moved to Heligods and rcgroups and not going back.

      Thread on HF regarding Gartt 800 just reached 17000 views and on epheli 26100 views. Assault 700 thread on rcgroups has 64 pages and 954 posts.

      I am glad people from Venezuela, Japan, US, Europe are interested and send me PMs. I have good experience with this heli as 800 and 700.

      All you have to do to read more is type Gartt 800 or Assault 700 in Google.

      Today I built Hyberbipe. It took less than an hour. Amazing plank. I can not wait to maiden it.



      I love Multiplex Gemini which was unfortunately discontinued. I was flying it in strong winds.



      Hyperbipe is much lighter. I have high hopes...

      [​IMG]

      Hyperbipe is definitely much less wind resistant but uses much smaler lipos 1Ah vs 2.1 Ah 3S and low weight shoud provide awesome performance.

      Can it tow 2.63cm wing span Cullaris?



      I got both of them:
      [​IMG]
      Second Cullaris is waiting in the box.

      For two 6S 4500mAh lipos for 700-800 (one flight) I can get 20 lipos for Hyperbipe 3S 1Ah 35C ;)
       
      Last edited: Jan 31, 2015
    17. utrinque

      utrinque Well-Known Member

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      Assault 700 upgraded 800 very low head speed 6S:
       
    18. smakmeharder

      smakmeharder Administrator

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      Actually a very interesting combo utilizing the low head speed with big blades. The Heli seemed to still have reasonable performance given the head speed. There is quite a bit of blade areal there... I can see why it would appeal to a large helicopter demographic given price/features
       
    19. Busher

      Busher Member

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      Great video, is that you flying it as well Utrinque ? Great flying

      Can you give us an idea of the headspeed? I am very interested in either using this setup or the 700 at low headspeed.
       

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