Gartt GT700 DFC stretch to 800

[utrinque]

New short video recorded yesterday:

800 (2 min 26 sec)

[utrinque]

....and another video of Assault 700 DFC flown by much better pilot than me:

Assault 700 DFC (4 min 25 sec)

In description there is information that he replaced only swash and main gear!

I have decided to get few parts for 800:
- 780mm Align blades from rcpioneer ($111)
- Main Shaft Spacer HN7075 USD $ 4.49 (thanks to HeliFreak) - great part if you put Align gears.
- CNC Slant Thread Main Drive Gear/118T H60G005XXW USD $ 18.74 (thanks to Emil) - to big if you do not have adjustaable motor mount (e.g. KDE)
- Metal Tail Pitch Assembly HN7079A USD $ 19.49
- Metal Tail Pitch Assembly H70097 USD $ 32.99

I will use Gartt tail assembly in 700 and after dissasembling I plan to use Loctite 638 to fix it (thanks to Benji)

I received third Gartt GT700 DFC kit including reinforced swash plate. I will use this swash in 700. It looks strong enough.

I suppose new Assault kits will include this improved swash.

Update: Ten more flights during the weekend. Danielus from epheli.pl helped me to set governor on YEP. 800 is quiet, smooth, even more agile with governor. I had to reduce flight time from 5.5 to 5 minutes but head speed in ID2 is higher now. This is my favourite heli now. I was flying a lot also with two stretched 700 helis, 600 EFL PRO and 450 PRO.

I was using 50% throttle in idle up to extend flight times (530kV motor). At 50% flips&rolls and inverted hover are easy. While setting gov store I increased temporarly throttle to 75%. Wow it has power... RPM was much higher than usual. 800 did not break at high RPM. ; ) I use Gartt GT700 DFC head.

In streched 600 with 700mm blades I use now Gartt main gear, pinion, tail boom and torque tube without any issues. Sound is not as good as with slant gears but main gear is strong enough.

[utrinque]

I like this heli so much, so I decided to build third one based on Gartt GT 700 DFC kit, second 800.

I was lucky to get cheap Align stretch kit and 800mm blades on eBay (from Viena) and now I am finishing this build.

[utrinque]

It hit the ground vertically nose in. I lost control. Possible causes:
- broken snap, probably snap of DFC head, others were from Align 800.
- lost radio signal - I was flying all day with two 800, two 700, 600 and plank and did not have other problems with radio signal. There was one guy who came and started flying FPV though.
- new HV servos could cause drop of voltage from 2S lipo for avionics and gyro lost its mind... rather low probability.
- I use non-DFC swash, so there is some probability that ball link could go off

I thought it will need rekit. I was surised. I lost only new blades , $4 canopy, 3 plastic ball links, main shaft was slightly bent and I replaced it. Tail boom is slightly bent but works just fine. I did not replace it. All gears survived!

800 is repaired already.

I was shocked skids were untouched, frame survived without scratch, tail was not damaged, Assault DFC head untouched except one link was slightly bent (this small part to which ball link is screwed). Replaced. All four servos luckily survived

I am really impressed with frame toughness and more than happy that damage was so marginal. Those blades were so good. This is my only concern.

I would like to know what happened for sure. Was it my fault or hardware malfunction?

In second 800 Assault snaps survived many flights, at least 5 today.

[runesb]

A another cause : Pilot error
(Or 3g/3gx) user

Happy y didnt get that much damage.

[utrinque]

Originally Posted by runesb

A another cause : Pilot error
(Or 3g/3gx) user

Happy y didnt get that much damage.

Thank you.

Flying clones makes me more cautious. I know I can crash due to mechanical failures.

I did not make an error on sticks this time. I did not fly extreme RPM nor extreme maneuvers. I just lost control. I use V-Bar clone. In hundreds of previous flights gyro did not fail on me ever. More often servos fail or take to many amps and cause brownouts to receiver or probably gyro also.

I'll never know what was the real reason of crash.

Anyway I am really happy to learn frame is tough.

After some reading I blame power hungry servos. It was probably brownout. My fault, I put only one power line to receiver.

One powerline was not problematic with RJX HV servos but on this 800 I use blue TGY-BLS815MG HV (rebranded KST BLS815 servos):
http://www.kstsz.com/threestyle/ksts.../17159074.html
http://tinyurl.com/o6s9fvb

[runesb]

Your rx is wasted ??

[utrinque]

No. After crash I checked if servos are moving. Rx and lipo were functional. One cell in 2S lipo was hurt in crash so I destroyed it making a lot of smoke ; )

Taranis is on its way. Align 800 ball links installed.

I hope it will eliminate any issues.

Update:

I decided to get YEP 180A HV. Last one at EU warehouse

After last weekend YEP 120A HV prooved to get to hot. Seems I fly it harder and harder and with governor and higher RPM is at its limits already,

[utrinque]

Assault 800 - 2014-04-10 (4 min 16 sec)

Many flights last weekend. First 800 is definiely my favourite heli. I was flying also 700, 600, 550 this weekend. 800 is the best by far. Second 800 is waiting for new Taranis radio. Radio departed Heathrow so I will get it this week.

I have measured 800 speed.

102 mph:
https://www.helifreak.com/showthread.php?t=615999

I am not going to join speed competition with $42 motor. Just wanted to know how fast it can fly. I was positively surprised motor did not get hot. It can go much faster.

[utrinque]

[ame]http://youtu.be/j5dItSq7Dqg[/ame]

Today I test Taranis.

In second flight strange, short, power loss.

I downloaded log from gyro and there was no loss of radio signal nor loss of avionics power.

I checked cables, YEP 180A HV looks fine did not get hot, cables look fine. Strange...

At least I know it was not Taranis fault.

Both 800s flying Today. I am very happy with new blue Turnigy servos (rebranded KST) and talkative Taranis radio. Awesome weather, strong wind. I like it. Not many pilots at the field today. Actually I enjoy flying alone now.

800:
[ame]http://youtu.be/-d6BOjTRkgg[/ame]

Gemini:
[ame]http://youtu.be/VQAL7QLIuus[/ame]

My coleague "maidened" bigger nitro bipe:
[ame]http://youtu.be/U57xVGQaMaA[/ame]

Update:
Today after few flights I had successful emergency landing. Autorotation after loosing tail authority, throttle hold was smooth and soft. No damage at landing.
- frame intact
- blades intact
- all gears intact
- skids intact
- TT, boom, boom supports intact
- servos, gyro, regulator, motor intact
- DFC head intact

Broken bolt fixing tail blade grip.

Second tail blade was broken probably by grip flying away. Actually during landing I did not notice strong vibrations.

I assume posibility of my fault. After replacing radial bearings for thrust bearings I could use to much force on this bolt to eliminate small playn of the grip.

We would see many reports if screws were not up to the task...

Again I was extremely lucky not to crash 800. Personally I am proud autorotation went so smooth. Actually it was my first auto with 800 ever.

http://oi57.tinypic.com/bjj2mh.jpg
http://oi60.tinypic.com/2zqschu.jpg

[utrinque]

800 repaired using plastic Align tail blade grips and Gartt white plastic tail blades.

Will they survive low RPMs? If not I will practice autorotation skills.

You can call me crazy.

Update: Four flights today after repair. It is fine. Plastic tail grips do the job well. Seems like bolt is weakest part.

Honestly I can not wait to fly her again...

I have third kit ready to stretch to 800 and all parts, but this time I will keep it 700 to be able to fly more dynamic with my weak 4,5Ah 30C lipos.

Update:
Unfortunatelly yesterday all day was raining.

Around ten more flights today with two 800s. Nothing fancy but they are still alive and kicking.
700 based on Gartt frame did not fly. Something was wrong with YEP 120A HV. Actually I was flying it but regulator was logging of aech few seconds so I had to land. After returning home I disabled governor and all is fine. I am not sure if this malfunction can be raleated to the fact that I replaced 9X receiver with Taranis FrSky receiver. Anyway I am very happy YEP and motor are not dead.

[utrinque]

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 any crash.
- 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.

Recommended reading:
https://www.helifreak.com/showthread.php?t=295533
https://www.helifreak.com/showthread.php?t=587363

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 over 100 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...


Update: My two Gartt (Assault) 800 helis are still alive and kicking. Third Gartt joned them today ad 700 with MAH blades (from Kostek... thanks). Over 10 flights and I like it a lot. Definitely there is huge difference comparing to 800s. I like both sizes.

Update: Only 6 more flights today due to the rainy weather.

[Garryk]

I like following this thread as I am entertaining getting one of these big birds.

[utrinque]

Thank you.

If you want to follow my suggetions, you can try to contact Alvin Lau at Gartt and specify exactly which parts you want and which not.

I would take frame, head and motor but swash, gears, tail and skids I would buy from Align. Get kit without canopy and choose canopy you want.

This way you will get best of clone and be safe.

Assault kit from Hobbyking for $222 from US warehouse is allso good option. Keep in mind shipment cost from China is high.

Check also this theads:
https://www.helifreak.com/showthread.php?t=582634
https://www.helifreak.com/showthread.php?t=558322
https://www.helifreak.com/showthread.php?t=587493
https://www.helifreak.com/showthread.php?t=587363

Update: Again over 10 flights today with Gartt 800 and 700. I am trusting them more and more...

I do not push their limits. I enjoy 800 more than 700. 700 is to heavy. With high RPM it would be a rocket but I prefer longer calm flights.

In last two days I crashed 600 EFL PRO twice. I was extremely lucky:
https://www.helifreak.com/showpost.p...&postcount=456

Update:

I did some inverted hovering 40mm away from my face today...

Not with 800 Just Nano CP X.

[Garryk]

I have to wait til my budget is back in order, but I'm thinking stretch to 800 with double frames and everything else you said.
I appreciated your optimism from the start of the release of this heli. I also appreciate your honesty in your reviews and tolerance of those who were more than a little skeptical.
I will add the total cost up and go from there.

[utrinque]

Thank you.

Clarification: I do not use double frame on my 800. I do not think it is necessary. Frame is pretty strong and stiff. Remember it survived hard crash. It does not mean it is indestructible. Few times I was just lucky.

[Garryk]

Oh OK,,, Thanks for clarifying that for me.

[utrinque]

Jan Erlebach 1.5.2014 - Assault 700 - Trutnov (3 min 59 sec)

About Jan:
https://translate.googleusercontent....msYv04sz4R6h1w

Align? DFC link failure crash:

T-Rex 700 DFC Crash - DFC Link failure (1 min 20 sec)

I setup Taranis radio for Nano CP X. Earlier I was using DX4. Orange transmitter works flawless with Taranis. Now Nano is even more controlable and flipps&rolls like crazy now. I set 70% expo on aile and elev for better stability at stick centers. Instarted to think about DFC head with 1,5mm insread of 1mm feathering shaft for Nano.

[Garryk]

WOW 70% expo is a lot. I don't like expo. I use travel adjust or whatever other means to tame the things down. but on my mcpx bl, It needs to be sped up. Rolls are way too sluggish. Same with my trex 600, but I'm taking off the beast X and putting on a true V-Bar soon anyways.

[utrinque]

I got Spartan bluetooth dedicated for Vbar. Actually it is not cheap but it can handle 8.4V of HV setups. I will be able now to modify settings at the field without netbook just with Android phone.

Be carefull with BTs from eBay. They can burn on 7.4V and need lower voltage. You can use them with small regularor.

Jan can fly:

Assault 700 8.5.2014 Jan Erlebach (4 min 25 sec)