View Single Post
Old 02-26-2012, 04:56 PM   #1 (permalink)
Long Nguyen
Registered Users
 
Posts: 1,443
 
My HF Map location
Join Date: Dec 2007
Default Goblin 700 Build Thread (refer to 1st post for latest information)

Hi guys I was lucky enough to acquire one of the early demo kits in the USA. All of these demo kits will show up at the Las Vegas funfly happening in 2 weeks! Come out and check them out.

This is the build thread of my Goblin 700 featuring photos, setup and in-flight data.

My proposed setup:

- Goblin 700
- Stock main and tail blades
- Futaba BLS351's for the swashplate
- Futaba BLS256HV for the tail
- Hercules super BEC at 8.4V
- Vbar standard size 5.2 Pro
- YGE 120HV ESC (16s version) + Vbar governor
- Hacker Turnado 400kv + 22T pulley
- 16s3800mAh for 3D flying at 2150rpm
- 14s3300mAh for slow headspeed 3D flying at 1800rpm
- Futaba TX and RX

26 Feb 2012 --> I have reached to the final steps of the chassis assembly. I am still waiting for electronics to come in. The electronic installation/setup will come later. Throughout the build, I have faced 1 issue so far: the spring used for spring-loading the belt tensioner would pop out of the crank arm when one tried to load the spring by rotating the crank arm. I simply fixed it by a piece of tooth pick inserted in the hole to act as a wedge to hole the spring-end in, then a drop of CA would weld everything in.

I did add extra 0.2mm shims on each side of the blade grips (one on each) to preload the dampeners as recommended by the SAB team.

One note to the factory: all pre-assembled parts indeed had threadlocker where needed but the assembling person seemed to over use the threadlocker. In my blade grip assembly, the threadlocker were more than enough; hence, the excess seeped in between the bearings and the shaft. It took some work to heat up the whole thing so I could take it apart.

Now come the build photos:




























































March 3rd 2012 --> 12s setup testing with the new Quantum 4530 500KV motor!

I have been waiting for some final electronics to come to finish the build. I got everything except for the YGE 120A 16s version (because I want to run a 16s setup). The ESC is not coming in another week so I decided to strap a 12s setup onto it for now:

Kontroniks HeliJive 120A
Quantum 4530 500KV motor (this is soon to be bundled with the kit)
Pulse 12s4500mAh 45C

Due to a little time I have right now and the weather has not been favorable, I only had a 2 minute flight yesterday with a few punch-outs and flips. Everything went successfully. Little do I know about it is that the collective is BALLISTIC! I was running only 12 degrees of pitch and 1900rpm, and the thing shots up the sky effortlessly! Don't forget to mention the quantum 4530 500KV definitely has a huge load of torque in it!

This weekend, I will be testing this setup more with detail information about the in-flight current draw, wattage and headspeed.

Besides, I have a few statistics for you guys: RTF weight without batteries = 3450g. This is with the HeliJive 120A which is a relatively light ESC (built-in BEC), and the 570g Quantum motor. The manual states 3290g (not sure with what setup). The Trex700e weighs pretty much in the same range.

For more information about the quantum motor, please visit: http://www.facebook.com/quantummotors

13 Mar 2012

Today I finally had some chance to fly my Goblin. I did totally 5 flights. I started to enjoy it more. Here is the report:

- Flight characteristics: For cyclic/ collective I didn't like it at first. I wanted it to be smooth, graceful and still do good smacks (like the logo 600). The goblin was solid but too STIFF. Too stiff to the point that the maneuvers were hard to carry out smoothly and gracefully. This is because of the goblin's extra stiff/rigid dampeners.
To adjust it to my like, I had to lower the Vbar main rotor gain to the 50's and still deviate from this point to improve it. Besides, the style value was high medium. With new Vbar settings, I started to like it much more!

At first with stock Vbar tail settings (tail gain was 70), the tail performance was poor under side way loops. The stopping power was not good either. I went ahead and raised the I-gain to 75 (I-gain kills the steady state errors hence helps stop power). My main gain was adjusted to mid 60s and it started to perform much better. No more loose tail in sideway loops and stopping power was strong and nice. Moreover, in very fast forward flight, the tail did not "shake" as much!
- Flight data: originally I wanted to run a 14s setup but I had problems with the ESC so I put this setup on hold. I have been running a 12s setup instead.
HeliJive 120HV with internal Governor @ 2100 headpseed
Quantum 4530-500KV motor + 22T pinion
12s batteries. One is 4500mAh 35C, the other is 12s5000mAh 45C.

With the 12s5000 packs flight time was better, the heli felt more powerful and I definitely liked it more. Here are the 2 graphs, one is for each battery.





The HeliJive did a good job in holding the headspeed. However, I still like the Vbar Governor better. I haven't setup Vbar governor on my Goblin (will do soon), but on my Protos 450 and Logo 600, it outperformed the Kontronik. Vbar Governor has a much better collective feel.

The quantum motor worked GREAT. It generates tons of power when I need and still doesn't drain much battery energy. On average, it consumes about 820mAh/min at 12s voltage. With a 5000mAh pack and 80% rule, with my flying style I would be safely able to get 4 mins and 4.5mins if I want to push it. I was pushing 6600-6700watts.
Bottom line, I started to like my Goblin more and more. I still have to find the sweet spots on both head settings and tail settings. I am looking for a good smack machine but still does smooth and graceful maneuvers. Power seems more than enough for general 3D purposes with the current setup.

Stay tuned for more reports!
__________________
Long Nguyen




Last edited by ChrisH; 03-14-2012 at 12:15 AM.. Reason: Updated at request of Long
Long Nguyen is offline        Reply With Quote