Hobby King / Hobby City 450 Helicopter Configuration.

Started by vinay, January 22, 2011, 03:50:48 PM

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samlikespad

Assembled the pro following "nuttcaze" videos. Whats pending for the frame is the feathering shaft which needs two 1.5 hex drivers ( I had only one  :banghead: ). The other thing I struggled is the head screw that holds the head assembly to the main shaft. Had to use two pliers on both ends to get it out since the 1.5 hex was not a proper fit for it. Managed to put it back after threadlocking rest of the head assembly but not happy with it  as the pliers were slipping, well its a mess :( .

Edit: couldn't do the canopy mount as well since I ddnt have any 1.3mm hex drivers either!

Now, two of the servo installations seems easy and possible while the third one behind the head seems challenging. I guess nuttcaze could have done better  :giggle:

samlikespad

Well, the servo installation went smooth even though I had to remove and reconnect the rods couple of time since I messed up with the channel selections and channel reversals  :banghead: Now all channels except RUD is connected and working fine. Am still not comfortable about the main shaft m2 1.4mm hex screw and its nut.

Now I have to find a way to mount the smaller HK 922 servo on the tail.

samlikespad

Maiden-ed her today with the help of Bilal (friend and fellow flyer). He identified atleast 5 major faults that I made during my setup and rectified them. How ever, as per him it still needs some more work as the head and most other things on it are having major play/slope causing issues especially at lower head speeds.

Video of me flying heli for the first time: http://www.youtube.com/watch?v=mHSe_lIGIo0&feature=youtu.be

samlikespad

Heli Experts, need help  :help:

Though I successfully maiden-ed it (with help ofcourse), still there are issues. The head is having a lot of slope (which is evident more at lower head speeds) causing the heli to dance in its axis. We tried a higher rpm/pitch combo later on and I was able to keep her almost in one place.

The other thing is that while setting her up, we found out that lower part of one of the washout control arm easily comes out. We conducted the maiden as well as my hovering practices using a small normal rubber band wrapped around the linkages. Did any one else face similar issues? how did they fix it? Is ordering Align parts are the only alternative to fix it properly? So many questions...

rajathv8

What do you mean by "head having slop"? Do you mean linkages having slop? The slop (if and) should be independent of rpm/pitch.

If the link comes out easily the heli is probable not flight worthy and potentially dangerous to fly. Rubber band wrapped around any link will lead to binding.

You can check RC Bazaar if you want to buy links :)

samlikespad

Hi Rajath,

The head itself has bit of play. It moves left and right on the main shaft. The heli dances as you could see in the video. Once its idle up or on a higher speed, it steabilizes. I visited and bought some spares from RCBazaar during my last short visit to Bangaluru :) But I dont think I have that washout control rod :( Will have to order now.

laxmansuthar

Tightness of main blade grip is cause of shaking heli at low rpm..just check your blade grip & Throttle curve..:)
laxman
Futaba T7c.2.4, boomrang trainer 46., 60size Extra 300s, Raptor 30v2, raptor 50 Titan, electric biplane, Thunder Tiger raptor 50 titan Se, J3 piper cub, Tarot 450 sports, Align 500,

Hellyflyer

From the video it looks like you need more head speed on normal throttle curve...look at some throttle curve videos on youtube to get an idea of the 450 heli throttle curve... if you have a programmable radio.
Helis and Quads ROCK !!

samlikespad

Thanks laxman, I will certainly check the blade grip.But still the slop is there. The head on the main shaft moves at least a milli to both sides if you try with your hand!

Hellyflyer

if the head is moving up and down on the main shaft just pull it up and tighten the collar on the main shaft so that it stays their.
Helis and Quads ROCK !!

samlikespad

Hi Hellyflier, exactly... we tried a faster rpm and she was much more stable. But am still worried about the slop. Is it normal for all 450s to have that much slop on the head? or should I think about changing the head? Anyhow, I will be changing the washout control horn.

samlikespad


Hellyflyer

Please demonstrate the slop movement thorugh a video
Helis and Quads ROCK !!

samlikespad

#113
Sure.. will do tonight. And thanks :)

Here is the video:

http://www.youtube.com/watch?v=dgDxwJ-1mjM

laxmansuthar

#114
Ok, i think this play between heli head & main shaft, this is a manufacturing defect..

for quick solution..
01 you put thine layer epoxy on main shaft where head fit & fix it & don't forget to wipe out excess epoxy...
02 if play in larger amount you just use aluminum foil paper to fix
03 fill baking soda where need & put one drop ca to fix...
04 for expert advise use R48 anaerobic retainer this will fill 0.01 mm play (use only where metal touch into metal)

for more..check  http://www.helifreak.com/showthread.php?t=413823

regrads
laxman
Futaba T7c.2.4, boomrang trainer 46., 60size Extra 300s, Raptor 30v2, raptor 50 Titan, electric biplane, Thunder Tiger raptor 50 titan Se, J3 piper cub, Tarot 450 sports, Align 500,

samlikespad

Thanks a lot laxman! I will start from the aluminium foil and if not good enough, then will go the thin layer epoxy way :)

samlikespad


rajathv8


samlikespad


samlikespad

Had my first crash! As per experts watching, one of the HXT900 failed  :banghead: The heli was hovering stable but all of a sudden it twisted itself to one side and kissed mother Earth. I was quick to cut the throttle. The main blades are gone, assume that the feathering shaft is gone too :( , main shaft I have to check. Enough homework for this week :D

But I cant leave with out mentioning this, I ordered couple of spares from rcbazaar last Wednessday for the heli to our Nagpur Office address (am visiting them end of next week), and today I received confirmation from them that the Box is already there!!! What a service!  :salute: to Sujju and his team this time.

rajathv8

Did you check the servos after the crash? Did the servos actually fail?

samlikespad

The Ail servo was not moving after the crash. What saddens me is that rajath, the heli was dead still hovering and I was so pleased at the stability... next moment it goes crazy and goes some what like a quick roll to the ground! I cut the throttle before it hit the ground. And by the way, forgot to mention, the head slop was fixed by tightening the head screw properly. After that it was rock solid and once the blades were re-tracked, it was amazingly vibration free and stable.

rajathv8

Can you please check if it the gears have stripped? :)

samlikespad


samlikespad

Rajath, the AIL servo had stripped very badly. Dont know whether this is pre/post crash. All the links were in place and I couldnot find any other reason for the sudden roll of the heli. Had a pack of HXT900 servo replacement wheels and changed them.
Servo re-installed, new cf blades installed, straightened the slightly bent flybar shaft, bent main shaft replaced with an racbazaar Hiller shaft,did a tracking test after balancing the blades and it seems ready for a test flight :)