HeliMax MX400 Problems  
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All Forums >> RC Helicopters >> Electric RC Helis >> HeliMax MX400 Problems
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HeliMax MX400 Problems - 12/2/2005 1:41:20 PM   
mimeauja


 

Posts: 21
Joined: 6/18/2005
From: Springfield, MA, USA
Status: offline 		If you're going to buy the MX 400 helicopter, then here's a couple tips for you.

Buy the upgraded (metal) center hub right away. The 'plastic' center hub is so cheap, it breaks if you start the motor too fast. (see my rant at the end of post)

Point two, related to above. Buy an ESC with a governor mode to control the rotor spin up and 'under load' rotations. (Castle Creations Phoenix 35 for ex)

If you want a cheap solution for servos, but the EFlite S75 servos. No one even comes close to the torque and light weight for $15.00

The HeliMax 6 pole motor is a really powerfull motor. You could easily overpower your heli with it, so start with a lower tooth count pinion and step up from there.


About the MX400, problems

This is the age we live in, where manufacturers know there are huge problems with things and do nothing to straighten them out. There is no possible way that HeliMax (Hobbico) could NOT know that this center hub problem exists. Oh yeah, there is one way, they never tested any of their helis...but we all know that's impossible.

Ok, so I've had this heli for a month, never flown it, but have replaced the center hub already. Why? because I accidentally hit the throttle with my hand when setting up the mixing. Oh, no, the heli didn't hit anything! the torque snapped the center hub.

Now, I've flown the heli. I've crashed it, and it was a head crash (tail is fine), so I want to buy a head crash kit. Only problem is, 1/2 the parts in there I don't need. I don't need a main shaft, I don't need a feathering spindle. No, I need all new linkages, a new swashplate (yes, that's right, it ripped the balls right out of it), basically all the plastic parts. (oh this is about $90 US)

Why? because the center hub broke, and everything torqued off from there. Believe me, if that part had held together, I would have been able to use the standard crash kit, and been just fine.

My advice, either buy the metal center hub for the MX400, or buy a T-Rex, either way, you're paying about the same. Otherwise, I'd stay away from this heli, no matter how well it flies, eventually you WILL crash it, and you know what happens after that.
       Post #: 1

RE: HeliMax MX400 Problems - 12/2/2005 3:36:50 PM   
bdavison


 

Posts: 3309
Joined: 8/23/2004
From: Warner Robins, GA, USA
Status: offline 		Id venture to say the same thing is quite possible with the stock plastic hub on a T-rex too.
Both the T-rex and the MX400 have a lot of power under the hood. If you dump all that power in an instant....stuff is going to break.
If your head didnt shear, you probably would have at the least taken teeth off the main gear. Even the little E-flite Blade CP will eat teeth off the main gear if you jam the throttle stick to full throttle really fast.

Dont be so quick to blame the heli, when it was your mistake.

_____________________________

teamflyingcircus.com

(in reply to mimeauja)
       Post #: 2

RE: HeliMax MX400 Problems - 12/2/2005 3:45:48 PM   
jh4db536


 

Posts: 530
Joined: 5/22/2005
From: Monterey Park, CA, USA
Status: offline 		youre suppposed to use "soft start" to prevent the head from snapping and also from stripping the maingear

the x400 head is designed to be weak on purpose for crash reasons, that's why it's so cheap

helimax/towerhobbies does not make the MX400, ARK does which sells updated versions under the x400 name.

why wouldnt you buy an esc with gov mode??? that's how CP heli are supposed to be run. no gov mode means, no softstart also.

if you think a helimax motor is powerful wait till you try a 450TH or Astro803T. IMO, the helimax motor is crap.

i dont like tower's recommendations on equipment for the MX400. they recommend only items that they sell and a lot of it is sub par not only in quality, but it's inadequate for use in a heli like the MX400. ie the 1250mAH lipos when x400 supposed to have at least 1800mAH. you should be using the same motors etc used in Trex.

(in reply to bdavison)
       Post #: 3

RE: HeliMax MX400 Problems - 12/2/2005 5:12:55 PM   
mimeauja


 

Posts: 21
Joined: 6/18/2005
From: Springfield, MA, USA
Status: offline 		Heli-Max is hobbico, see here http://www.hobbico.com/

quote:

if you jam the throttle stick to full throttle really fast


um, I didn't hit full throttle, more like 1/4 throttle, and I do have the ESC in governor mode (ultra soft start). The part is junk.

How many people have broken this part already? Respond to this message, thanks.

(in reply to bdavison)
       Post #: 4

RE: HeliMax MX400 Problems - 12/2/2005 6:30:21 PM   
jh4db536


 

Posts: 530
Joined: 5/22/2005
From: Monterey Park, CA, USA
Status: offline 		a video of my soft start (6megs): this is how it should be :

http://media.putfile.com/soft-start-idle-up

im using approximately the same ESC, phoenix45

(in reply to mimeauja)
       Post #: 5

RE: HeliMax MX400 Problems - 12/2/2005 6:31:43 PM   
kevntri


 

Posts: 141
Joined: 6/29/2003
From: rockford, IL, USA
Status: offline 		Broke one on a landing...
Brought it down to about 4 inches and set it down and SNAP....

(in reply to mimeauja)
       Post #: 6

RE: HeliMax MX400 Problems - 12/2/2005 6:41:12 PM   
bdavison


 

Posts: 3309
Joined: 8/23/2004
From: Warner Robins, GA, USA
Status: offline 		jh4db536....

That was georgeous.



_____________________________

teamflyingcircus.com

(in reply to kevntri)
       Post #: 7

RE: HeliMax MX400 Problems - 12/2/2005 8:55:37 PM   
EZ Money


 

Posts: 149
Joined: 6/3/2003
From: Las Vegas, NV, USA
Status: offline 		Mine broke last week when I was setting the pitch. same way, I bumped the stick and it hit my arm (it smarted too!). I have since replaced it with a metal head from ARC (Grand RC) and metal blade grips.

What a job that was. The ball links on the collective are very hard to get to to unsnap and re-snap.

Tell me more about soft start. My ESC does it but I thought something was broke so I put the setting back on number 1 for airplane.

Ron

_____________________________

Ron Landram
http://www.ezmoneyracing.com

(in reply to bdavison)
       Post #: 8

RE: HeliMax MX400 Problems - 12/3/2005 12:20:18 AM   
rwthomas1


 

Posts: 64
Joined: 11/17/2004
From: Wakefield, RI, USA
Status: offline 		I have yet to fly my X400 however I have had no problems with the head yet despite numerous spooling up and down of the assembly during setup. ESC is Phoenix 35 and soft start is on. Will report when I actually put it in service. Regarding getting more parts than you need in a crash kit that just seems to be the way it is with all heli makers. You can get all the parts individually from grandrc and others. So the X400 head is weak, so what? Upgrade it and enjoy the heli. Any heli you crash will need repair. RT

(in reply to mimeauja)
       Post #: 9

RE: HeliMax MX400 Problems - 12/3/2005 12:47:13 AM   
credence


 

Posts: 2518
Joined: 5/19/2005
From: Brampton, ON, CANADA
Status: offline 		Heli-max is a Great Planes brand. As stated, they only re-brand and re-distribute the helicopter. It's actually made by ARK Taiwan. It's more expensive than the X-400 kit because you pay for the name and, to an extent, support. I'd imagine replacement parts for the x-400 would be cheaper in comparison aswell compared to buying them under the MX400 name.

As for your problem, well, gunning the throttle breaks things. It's not an MX400 specific problem. Most helicopters will sustain damage if you jump the gears when the main blades aren't atleast rotating. Learn from your mistake and engage throttle lock from now on when adjusting things on your helicopter or transmitter. I won't do anything on my heli unless throttle lock is engaged.

< Message edited by credence -- 12/3/2005 12:49:13 AM >

_____________________________

Daniel
True Northern Hobbies, Inc.

(in reply to rwthomas1)
       Post #: 10

RE: HeliMax MX400 Problems - 1/10/2006 1:17:06 AM   
t--bone


 

Posts: 6
Joined: 1/8/2006
From: woodstock, IL, USA
Status: offline 		the plastic blade grips are worthless if u grab them they will twist out of center . i put the alumium ones on they are great . now i guss i got 2 get the metal main head

(in reply to credence)
       Post #: 11

RE: HeliMax MX400 Problems - 1/10/2006 2:52:58 AM   
danlee1


 

Posts: 22
Joined: 1/14/2004
From: Weston, FL, USA
Status: offline 		Has anyone had issues with the rudder servo linkage not being long enough? I bought the recommended servos and the tail responds very slowly and not too smooth throughout the range. I thing a longer linkage would help but I'm curious if anyone else has had the issue. Thanks,

Dan

(in reply to t--bone)
       Post #: 12

RE: HeliMax MX400 Problems - 1/10/2006 3:30:15 PM   
jaless


 

Posts: 42
Joined: 8/11/2005
From: Howell, MI, USA
Status: offline 		Dan,

See Trex build thread at http://www.trextuning.com/.

Look at build step 21. The links on the MX400 tail may be backwards. I have read that the grips should be in front of the leading edge of the tail blade. I happened to stumble on this last week and this change made quite a difference to the rudder control. Be sure to reverse the Gyro and servo if you make this change.

Joe

(in reply to danlee1)
       Post #: 13

RE: HeliMax MX400 Problems - 1/10/2006 5:56:31 PM   
jaless


 

Posts: 42
Joined: 8/11/2005
From: Howell, MI, USA
Status: offline 		Dan,

After making this change I was able to shorten up the rudder linkage but there seems to be many opinions as to which way the blade grip should be. The trex build thread said it should be leading the tail rotor but on the x400 build thread it shows the grips trailing. Does anyone else have an opinion as to which way they should be? I have them leading and I did have to change the gyro and servo direction and also shorten up the servo linkage but my tail control seems to be better and more even in both directions. Lets see if anyone else has an idea. I am new to RC helicopters and I would hate to tell you wrong but this does appear to be an important issue that needs to be cleared up.

Joe

(in reply to jaless)
       Post #: 14

RE: HeliMax MX400 Problems - 1/10/2006 6:19:00 PM   
danlee1


 

Posts: 22