Hover bobbing up and down (Head/swash slop the cause?)

[Raven_darkcloud]

Thats good. also try a higher head speed and you could get smoother flights. I'm adding a head speed/pinion calculator (excel format) to the build section.

[StatiC]

Still no reply from HeliMax. Looks like thier support email address is not working at all or they are ignoring me.

[Raven_darkcloud]

hmmm, thats odd. I have tried to duplicate slop in my head but all I get is from the links and flex of plastic parts. Try Li chann (ark) Not at home so I can give the exact email right now, but if you chech the site its there. I talk normaly to a guy named Bonbon or Benbon or somthing like that I cant remember but lots of help. if you can get vid of it then I can get a better answer.

[StatiC]

I will try and get a video of it but I don't think the resolution will be good enough to show the problem very well. My sony 5mp camera that takes video too does not seem to focus well on close objects. My shapr DV camera would even be worse I think.

When you hold the flybar and very lightly twist the main blade holders it causes the mixing arm rods to twist the top red part of the swash plate in different directions(up on one side and down on the other) while the bottom part of the swashplate stays stationary. That is the movement that translates to 2 to 3 degrees of main blade pitch slop.

I will see how well the video comes out tonight.

[Raven_darkcloud]

I do stand on the piont of, go ahead and replace it. That just sounds like a crash waiting to happen. Then keep hounding helimax about it for a spare.

[Raven_darkcloud]

helihotline@greatplanes.com
try this one and bug the cp out of them.

[StatiC]

Originally Posted by Raven_darkcloud

helihotline@greatplanes.com
try this one and bug the cp out of them.

That is what I used. I have sent 2 emails within a week.

The DV camera is taking pretty good video up close so I should have a video of it hopefully by tonight.

[StatiC]

Well after looking very closely at the swash plate, It looks like the slop is in the bearings and not in the part that gets glued by the manufacturer. I have noticed a faint high pitch whine to the heli so the bearings must be going. I purchased the heli used though so it has always sounded that way to me so maybe it is a normal sound. The bearings must be going though because the old mCCPM swash plate has zero slop in it and the eCCPM swash has a ton of slop in it where the bearings are.

I was thinking about trying to move the bearings from the mCCPM swash plate over to the eCCPM swash plate and using jbweld to put them back together but I am afraid of ruining either one by trying. I would have to remove the bearing completely from both swash plates. With my limited amount of tools I don't think there is any chance of it happening without destroying something in the process . I hate the thought of down time too.

[Raven_darkcloud]

Id say just get the replacement on order or pick it up at the lhs.
One correction on mccpm, no such thing. Helimax is bad about using that term. ccpm (cyclic collective pitch mixing) is the setup you are runing and the normal x400 that they call mccpm is mechanical pitch or mpm (mechanical pitch management/mixing depending on who you talk to). There is no mixing in mpm setups. This is not a nock on anyone just geting facts strait.

[StatiC]

My wife banned me from heli purchases for a month $200 in repairs the past 1.5 months is probably the cause.

I remember 15 years ago hearing the term CCPM and it was to distingush when the helicopter's swash plate moved up and down(by mechanical means like the non upgraded regular mx400 and mx400 pro). A non CCPM at the time was one where the collective pitch was controlled by a rod that went up the center of the main shaft to control collective(the swash never moved for collective input). For someone to say that the normal mx400 setup is not CCPM is really not correct going by that older meaning. It seems like manufacturers started claiming CCPM for the electronic mixing of the cyclic servos for pitch changes which seems to have confused the whole meaning of the term. 15 years ago there was no such thing as electronic mixing using the cyclic servos.

[Raven_darkcloud]

Yup. But the new mech way is the lever moving the swash. well unless you got a shogun or walkera 35/36. Look at it spelled cyclic collective pitch MIXING. there is no mixing on the mechanical, each servo works on its own.

[StatiC]

The lever moving the entire swashplate assembly up and down is the old way which was called CCPM back then. Non CCPM was when the collective was totally separated from the cyclic movement in the entire head. A rod went up through the main shaft instead which moved the main grip pitch directly.

So there is mixing happening with the regular MX400... it is just above the swash plate. When you move collective the entire swash plate moves up and down which changes the arms above it. When you change cyclic input it mixes with the same arms above as the collective to produce an overall change. Thus there is mixing going on(mechanical). The newer definition seems to be targeting things below the swashplate.

None of this really matters though. However the current industry defines things is how we should reference them. I will call it Standard mechanical mixing and eCCPM from now on so there is no confusion.

[Raven_darkcloud]

Thats true. But the new way, and this will most likly be the old way in a few years, Is the norm now.
Back to the main point The trex plastic swash is cheap and could get you through till you get a new cnc one. Like you I hate down time, thats why I have some of the align parts on mine. They fit, are in stock at my lhs, and the price fit my wallet. as for the baring replacement idea the lower part og the plastic ark swash is easy to remove so I'd say stard on the plastic to see about rebuilding the cnc one. cuz you may be atleast able to put the center of the plastic into the bottom of the cnc one. and If you can rebuild the cnc swash this would be varry usefull to everyone. Maybe if you go to Bobs area for fixing the trex swah and ask him about the swash he might know somthing the rest of us have missed.

[StatiC]

Thanks for the info. I didn't know for sure if the plastic swash on the rex would work on the mx400. My local hobby shop carries one so I'll pick it up and use that. In the mean time I'll try to get the swash apart on the old MPM swash plate.

[Raven_darkcloud]

sweet. let us know about the swash rebuilb.

[StatiC]

HeliMax support is shipping me a new eCCPM swash plate for free to replace the broken one. Looks like I will be sticking with HeliMax. I was contemplating switching parts (like swashplate) over to T-Rex. Knowing that they support their Heli's the way they do I will stick with them.

I have grounded the heli until the new swash is on since I am afraid it could come apart at any time.

[xp67]

It could possibly be just radio setup. The point for hover is very fine. I fixed my stock x400 bobbing up/down twitchiness by softening the pitch curve and throttle curve at the point of hover. Adjust both curves so that there is very little increase in both pitch and rpm at the point of hover. Try it before resorting to replacing parts.

[Raven_darkcloud]

That is a way to mask it if you have a 7 to 14 point curve. the real name of the game is to have a sound setup with no play or slop, ans learn collective management. Having good head speed is needed too. You want to fly by pitch. The problem in this case was a bad swash and helimax steped up and sent a new one free.