Gartt GT700 DFC stretch to 800

[utrinque]

To moderators: Please do not move this thread to 700 subforum. I want to get opinion of those who fly full sized 800 helis.

There is new option to enter 800 class.

I am going to stretch Assault 700 DFC. This kit is available for $215.
Gratt Model ShenZhen is manufacturing it. New Chaos 700 V2 is the same frame.

Gartt GT700 DFC:
http://www.garttmodel.com/EN/product...621&kindid=351

Assault 700 DFV
http://www.hobbyking.com/hobbyking/s...opter_kit.html

Prototype of Chaos 700 V2:
http://chaoscrewlounge.proboards.com...6/chaos-700-v2

I like the fact that all T-Rex 700 drive train is compatible with this kit. So in worst case scenarioo I can put all Align gears.

Stretching it to 800 is piece of cake. I am going to use this: 800 Upgrade Tail Assembly H80001


I have confirmation directly from Gartt Model that it is made of 7075 aluminum. I am not sure about Assault and Chaos versions. They can be different

I have experience with 700 class helis. I fly 2.9kg T-Rex 600e CF stretched to 700mm. Hundreds of flights proven that this is very reliable if RPMs kept low.

https://www.helifreak.com/showthread.php?t=489222

I plan to use:
- SK3 T700 480kV 4kW motor
- YEP 120A HV (160A regulator would be better)
- RJX HV servos
- HV tail servo
- Tarot ZYX
- 4500Ah 30C lipos
- 800mm blades (e.g. Align, RJX FBL)

Definitely whole cost will be below $1000 excluding lipos of course.

HobbyKing sold around 50 kits out of 75 from second batch in relatively short period.
http://rcsearch.info/hobbyking/i37562/#catalog

First I want to fly it with 700 blades. Definitely I am going to try with stretch. It would be light weight 800 heli. Did I mention... quite cheap comparing with competitors.

For those who think stretch is not good idea:
https://www.helifreak.com/showpost.p...&postcount=779
https://www.helifreak.com/showpost.p...5&postcount=11
https://www.helifreak.com/showpost.p...1&postcount=37

Any comments are welcome.

[utrinque]

For unknown reason I can not modify first post.

I just want to mention this project started in another thread "Do You Trust The New HobbyKing Assault 700E DFC":
https://www.helifreak.com/showthread.php?t=558322

You can check also this one:
http://www.rcgroups.com/forums/showt...0#post26972193

[utrinque]

FUBAR as a product was banned on HeliFreak due to the fact it was using stollen Mikado firmware. Later it was withdrawn from HobbyKing probably due to Mikado's intervention:

https://www.helifreak.com/showthread.php?t=528841

ddj74 expressed his opinion regarding Gartt products:
https://www.helifreak.com/showpost.p...0&postcount=70

According to ddj74 Gartt Model is "thief" and produces "junk".

We have two options:

- All threads regarding: clones, Assault, Gartt, HK clones e.g, Copter X, Chaos, copies of MKS servos, V-Bar clones (e.g. K-Bar), DFC FBL heads (which are copies of Compass design), YEP regulators (YGE clones) should be removed from Helifreak immediatelly.

or

- We can leave this to lawyers and companies. It is their business. As customers we can keep informing each other, keep our options open, investigate, decide not to buy from companies which copy designs.

Generic products are typical in pharma industry. Usually they are cheaper. They can not be marketed before patent expiration. They have to prove biosimilarity and do not have to go through III phases of clinical trials.

For some reason Align is not fighting clone manufacturers. There are many of them. This is the reason why Align is so popular. Many pilots starting with cheap clones move to Align later or buy original Align parts.

I use both oryginal Align parts and parts from clones for my helis:
https://www.helifreak.com/showthread.php?t=489222

There are many not oryginal parts not worse or better, often cheaper than originals:
- Fusuno frame for X5
- OWB bearings from HK600GT
- HK600GT cheap CF frame (much better tham oryginal Align GF ESP frame)
- tail booms
- skids for HK600GT - I use them on 700
- Rakonheli and Microheli aluminium Nano CP X and mCP X swash plates
- servos - Power HD, RJX HV
- gyros - ZYX, Beast X clones, etc.
- motors - SK3 T700, new 700 class motor at HK for $50 (I did not try it yet)
- YEP regulators
- 450 main shafts
- tail supports

and many others...

My friend reported weight of brand new T-Rex 700 v3 3624g without lipos:
- motor Align 800MX.
- HV (no BEC).
- he removed DFC and used classic FBL
- vBar instead of 3GX

Tarsan Karlik (Czech) reported Assault 700 DFC weight 3283g without lipos (341g lighter than Align)
- Motor Align 750mx 530kv
- castle creation 120 hv
- savox2252mg tail
- 3x HK 15298 cyclics
- Msh Brain gyro
http://www.rcmania.cz/download/file....6315&mode=view

4926g with lipos:
http://www.rcmania.cz/download/file....6316&mode=view

More photos here:
http://www.rcmania.cz/viewtopic.php?...589b0&start=45

I like this one:


It does not look like "junk" produced by "thieves".

HK sold 110 Assault kits in total since 10th of October (look for "Stock level dynamic"):
http://rcsearch.info/hobbyking/i37562/

You can still get one from Gartt. Negotiate price.

[utrinque]

I am sorry, double post. Please delete.

[nightflyr]

utrinque,

I have been following your project
I would offer some suggestions.

First and foremost would be frame rigidity..
The only machine I have that is utilizing a carbon fiber frame set is my BlackBird build.
The frame set is ~ 3x stronger than any commercially available, standard CF frames are manufactured with 5 - 7 tons of pressure.
The BlackBird was fabricated with 20 tons, making them tough as iron, and extremely rigid.

My other builds are utilizing metal skeletal frames.
My suggestion to you would be to double up and adhere the frame sets together to ensure strength and rigidity.
Something I did on the 1000E project along with frame bracing to prevent lateral flexing on the lower halves of the frame set.

Without having a set of frames to test.....
In your case stretching a 700 to 800, doubling up the frames may be all that is required depending on how strong the frames are and how you plan to fly it.

As to your drive train....
Suggest you fit the strongest main gear available. I found it quite easy to shred standard main gears with very little effort.
For my 800's and 900's the best gears I had ( FAD MOD 1 which are no longer available) tend to hold up, though they can still be stripped.

For the 1000 I went with an all metal main drive gear.
You might also look into installing a set of metal TT gears in the boom block assembly.

[Feral]

Double up the frames with aeropoxy as suggested and replace all gears, shafts, ball links and bearings with Align you should have no problems. FWIW I own trex800 dfc pro and a trex700 dfc pro and im negotiating an assault 700 from a mate that will be night rigged and ill be replacing everything I mentioned with Align gear

[utrinque]

Originally Posted by nightflyr

utrinque,
I have been following your project
I would offer some suggestions.

Thank you nightflyr.

I was thinking about doubling CF frame earlier. When I saw video from Matt I realized this frame is strong:
https://www.helifreak.com/showpost.p...2&postcount=53

I am not in a hurry with stretch to 800. First I want to test it in stock form with 700mm blades. I ordered two frames so if there are signs of low rigidity I will double it.

Trekker can be pushed quite hard. It has the same drive train as 700. I have checked it.

On all my bigger helis I program my radio (Open TX) to accelerate slowly so even erratic fast movement of the stick can not strip main gear.

I was using Align slant mod 1.0 main gear on all my 600 and 700 helis. It is pretty strong.

It is good to know you want to help. In the past I learned a lot making stupid mistakes. After each crash I analyse what was the reason. If I crash Gartt you will know why it happened.

Update:

Interesting is Protos Max 700-800:
http://www.msheli.com/Category.aspx?ID=11

First look at main plastic frame:


only upper part of the frame is CF:


This model can handle 800mm blades. Frame looks very fragile, but it flies great:

IRCHA 2013 Dario with the MSH Protos 800 (2 min 19 sec)

What is the secret? Materials? Low weight? "Monoblock" design?

HK sold 110 Assaults kits since 10th of October, but MSH sold 400 Protos kits on pre-order in two weeks. They will start shipping in January 2014.

[utrinque]

Originally Posted by burn666

replace all gears, shafts, ball links and bearings with Align

I will if it is needed. First I want to test stock gears. I would be not surprised if they are stronger than Align. Same regarding ball links. I do not particularly like stock Align bearings. They are fine but Gartt has NMB bearings. Let me give them a try.

There are already second hand reports of blade grips breaking in flight at low RPM and stripped main gear.

Do I care? I will when I see first hand reports and photos. I want to keep this "toy" in one piece. I will play it safe. On the other hand I want also to test its limits.

Everytime I crash I learn. I did not reach limits of my old 700. It has cheap $28 CF frame from GT600HK without any reinforcements. Usually I fly it at much lower RPMs than I did when I was testing it.

Originally Posted by burn666

FWIW I own trex800 dfc pro and a trex700 dfc pro and im negotiating an assault 700 from a mate that will be night rigged and ill be replacing everything I mentioned with Align gear

It is good to have you around knowing you want to help me.

I am not stubborn. If anything is not good enough on Gartt I will upgrade it.

Essence of this project is to prove bashers are wrong. So I will test it harder than I ussually do.

I do not like DFC design. But I will keep it to test it. For 800 I prefer RJX FBL 90 head. Nightflyr was using it in the past.

Come on... Two good servos are more expensive than this kit. You can get 700mm CF blades for $30 now. I fly such blades and I love em.

I promise to be carefull. This project is much less crazy then my earlier stretch and I am more experienced now.

[Feral]

The gears didnt even last 1 spoolup ( soft start enabled )on my mates assault the gartt my be better but I doubt it. If the bearings are good then it should be a cheaper build.

More than happy to help mate plus ill be watching this thread I love my 800 and if this works out for you ill stretch the assault if he parts with it

[Feral]

90% of the helis I own are dfc there is NOTHING wrong with them they have never failed on me keep the ball links straight on the balls and you wont have to worry about links popping off under stress

[utrinque]

Originally Posted by burn666

The gears didnt even last 1 spoolup ( soft start enabled )on my mates assault the gartt my be better but I doubt it.

Is your mate on HF?

Please ask him to report it in this thread:
https://www.helifreak.com/showthread.php?t=587363

[utrinque]

Originally Posted by burn666

90% of the helis I own are dfc there is NOTHING wrong with them they have never failed on me keep the ball links straight on the balls and you wont have to worry about links popping off under stress

Sure my goal is to test it. It will be my first DFC. I am curious what it feels like in flight.

I do not like the idea and design concept of DFC. Even Nano CP X has "something" to suport links.

[Feral]

Originally Posted by utrinque

Is your mate on HF?

Please ask him to report it in this thread:
https://www.helifreak.com/showthread.php?t=587363

Nah man he doesnt do forums these days.

Dfc to me feels a bit more agile depends what your after just keep your ball links straight and your dampeners tight and you shouldnt have any dramas

If you have any questions feel free to ask mate

[utrinque]

Originally Posted by burn666

just keep your ball links straight and your dampeners tight and you shouldnt have any dramas

Sure

I remember Bert K movie:

Assembly and Maintenance Tips for the Goblin Helicopter (18 min 38 sec)

New Gartt GT700 DCF flight videos:
https://www.helifreak.com/showpost.p...5&postcount=68

Some photos:
http://www.rcheliaddict.co.uk/main-d...ml#post1073035

Intreresting story regarding Chaos 700 v2:
https://www.helifreak.com/showthread...53#post5522653

[utrinque]

Originally Posted by nightflyr

As to your drive train....
Suggest you fit the strongest main gear available. I found it quite easy to shred standard main gears with very little effort.
For my 800's and 900's the best gears I had ( FAD MOD 1 which are no longer available) tend to hold up, though they can still be stripped.

For the 1000 I went with an all metal main drive gear.
You might also look into installing a set of metal TT gears in the boom block assembly.

Do you mean Full Metal Jacket?:
http://m.rc.runryder.com/helicopter/t706830p1/

I had metal front TT umbrella gears in my stretched 600. They wear very fast. I had to replace them with plastic. I am lucky I noticed a problem before crashing 700. Metal was aluminium not steel. Waste of ammo...

[nightflyr]

Correct on the main gear

[utrinque]

Why those holes are so big?


I do not like it.

I can live with that. I have to invent something to deal with this issue.

I did not receive my kits yet. This is photo taken by my friend building another 800 based on Assault 700 DFC.

[nightflyr]

Adjustability I would imagine to align the main shaft, also to ensure there is no binding in the servo operation.

[utrinque]

Originally Posted by nightflyr

Adjustability I would imagine to align the main shaft, also to ensure there is no binding in the servo operation.

Looking at Align T-Rex 700 v3 manual it has also big holes and specific "socket button head colar screws" (code 700HB12)

Update: Assault also has "colar screws" but still there is some play:

Assault 700 DFC - frame screw (0 min 12 sec)

To much play for my liking...

[satsuma]

Strange about the over over sized holes, but im certain something can be done.
Will be terrific when done and flying though
Correct, the Align 700 and 800 have collar screws for the motor and bearing mounts with just a TINY bit of play for adjustments.