HDX TROUBLES--HEAD LOCKS & EXPLODES

[n2750w]

I have a HDX 450 V3 and have nothing but trouble with it . 3 times just before lift off ,light on the skids the best i can tell the main rotors glitch or just STOP!! No damage to main blades,but bends main shaft feather shaft and roasts servos. I am not a beginner,used to fly 60 size nitro few years back.I have heard HDX had some bad kits shipped awhile back. I have had a severe vibration from beginning, best i can tell its from the motor. This last incident right before lift off head locked again,main blades EXPLOADED going in diffrent directions.Twisted main shaft broke tail blades. ANYBODY got any ideas whats wrong??? :arggg:

Have checked everything I know to check. :(

[gadawg58]

Interestingly enough my TREX 450 SE V1 head just did the same thing...light on the ground and boom...bent main shaft, flybar, boom. Blades just seemed to explode just before lift off. This is after 200+ flights on the chopper! I too am a bit puzzled. :arggg:

[n2750w]

Not glad to hear it ,,but nice to know someone else knows i'm not crazy! I gave up on my motor put in an ALIGN 430, 100% better. I tried to tell the people at CNC HELICOPTER where i bought it, and they blew me off. No help O WELL , i have since switched my whole frame to ALIGN SE CF. Out of all the Head LOcks,and rebuild time I got about 8 Minutes of hover time, HOPE YOU ARE MORE FORTUNATE!

[BobOD]

I can't see how the motor could cause a head to lock up. There's a one way autorotation clutch. See any signs of binding linkages?

[Graeme]

See any signs of binding linkages?

Or bearings?

[falconea45]

I wonder what head speed they were running. Blade balance, head dampers too soft etc.

[gadawg58]

On the trex450se I was running 3020 rpm with the wood blades. Think that was my problem as I went back to the carbon fiber and haven't had a problem since. I too have an hdx450 and while the head hasn't exploded just about everything else has! The sad thing is that the hdx450 flies great in between in flight failures just the parts they are using are very inconsistent. Have had to replace the main bearings many times even without a crash. Only getting 15-20 flights before vibration kicks in due to the bearings starting to come apart. Heck, the flybar they ship with the kit won't even fit through the bearings. To make it worse, you order a new one and the Sonix flybars they ship still don't fit. Just put in the trex flybar and moved on. Good luck to the hdx flyers...mine will most likely have a meeting with ebay in the not too distant future...not to get my money back, just to keep me from continuing to spend it on this one heli! :)

[REF]

I bet it's the main shaft.....the one that came with the kit.
Use a hardened or an Align mast instead.
Probably soft metal in the mast....from HDX.
I've built a HDX 450 from scratch....Align head "plastic except for swash" with align mast
HDX cnc tail. It flies great.
Just my two cents.
REF

[Dwntyme]

Just throwing something at cha' I wonder if one of the leeds going to the motor from the ESC is losing
connection . I've noticed when I have one wire dis-connected from mine (checking pitch) that the Motor
seams to lock, I'm not able to turn the motor while one wire is disconnected....Just a thought...

[damyxz]

Set your pitch curve right and replace all the ball links with align ones. The HDX ball links are soft and easily strips threads. also loosen the blades from the grip just a tad to allow it to set during spool up better. Disassemble the rotorhead and locktite all metal-metal screws. I have an HDX FSE for about 1 year now and still no problems.....It's all in the setup.

[Dwntyme]

I Have a HDX300 and I had a V2 head blowup, what I noticed was the part on head that the washout block
goes to(has 2 pins) the grubs that hold it to the head has really nothing to bite so what I did was made
some small dimples so the grubs wouldn't allow it to slip....Hummm

[damyxz]

As long as you measure the flybar and make sure that it is exactly centered. Use a caliper to do this. Weight the flybar paddles before installing them and balance if there is any discrepancy between the two. I go as far as disassembling the rotor head and making sure that each part is symmetrical in weight. (I use aluminum tape to balance it out). I do the same procedure with the tail assembly. Wooden blades are not designed to go over 2400-2600 RPM. I always glue the blade holders to the blade with 30min epoxy before balancing them. I make sure everything is balanced. These steps are necessary especially if you are running high head speeds(most of these mini heli kits are not designed for high head speed), A tenth of a gram difference in weight from both sides will translate to severe vibration at normal speeds and will be catastrophic at high head speed. The tail rotor needs more attention especially with being balanced since it turns 4-5 times the speed of the rotor head. I make it a point to actually change the main bearings of the motor on most off brand motors to ABEC 5 bearings to prevent future disasters. Most of these kits are labeled"for novice and expert pilots" .. this is because beginners will miss a few important steps in assembly and will have bad experience out of the box. These steps I take seriously when building and so far I have different helicopters from different brands(no e-flite though..hated the brand) and I do not have any problems other than normal wear and tear and occasional ground hugging. Careful assembly = great satisfaction. Happy Thanksgiving day!!

[veegor]

Well from what I have expenericed with the HDX450 since it is my one and only bird in the Hangar .....Dwntyme and Damnxyz have covered the main exploding issues to a tee!!

YOU BEAT ME TO THE PUNCH DWNTYME THAT Is The source TO THE EXPLODING HEAD .That Head lockup issue. That washout block has and will slightly rotate around because of the lack of grip by the grub screws holding it on the base of head. Its happen to me twice on a Spool up on the ground and in a mid flight hover. The base rotates slightly ..causing the linkage rods from the mixing arms to swash to mis align ...this causes the linkage rods to bend and pop off of the balls and Lock up ...

I have made a small flat spot on base for grub screw , SMALL AMOUNT OF CA. ON grub screw. and change to align linkage rods there not so thin & stronger than the soft metal Sonix rods.

The tail issue while doing as mentioned by Damnxyz also check the tail slider it has a tendency to loosen up as well. (the brass sleeve that slides on the tail rotor shaft) . Hope that helps ..The HDX450 is a nice bird to fly but does need looking over after so many flights .

[damyxz]

Nice bird Veegor. The HDX series of helicopters are really good value for what you get. But a lot of people overlook the fact that this series of helis are not for beginners. One thing that bothers me about the mindset of newcomers is that they think they have to have the most "bling" on their machines in order to fly good. Then they blame it on the heli, and the manufacturers if something goes wrong. They forget that no matter how much shiny stuff they put on their machines, it will not fly if the pilot don't have the skills. A part of this hobby is the actual bulid and set up process which require some aptitude with electricity, electronic components, and mechanical know-how. It takes an experienced hobbyist to guide a newbie(no getting around this one). The internet is good but actual hands on instruction can't be beat. Anyway the HDX series of helis is not for beginners but for novice and expert pilots. That's my opinion on that matter.

[veegor]

Thxs for the compliments on my heli damyxz : ) ...Yeah my heli has had lots of bumps, repairs and custom mods along the way.

I too agree with ya!! It seems way to common again as mentioned with this thread
That so many people are quick to post negitives experiences without knowing the many variables of RC HELI Flying.

RC heli flying is great but still This and other series size helis are small working machines which , produces high RPM's , fast mph speeds, ,When parts are not checked and something shifts , Parts will cause a items to exceed there tolerances fast ..Its only expected that we learn faster how to limit any possible failures before they occur.

[kl-motor@hotmail.com]

must repeat Finless.... remember to aply loctite!!!=) wihtout you dont fly any longer than 5min in worst case before the parts are starting to fly around!!!