New to MX450 and have a few questions.....

[siconic]

I am relativly new at helicopters, and I need some help. I have had an MX450 for 5 months and never flown it. The reason Is that I have had many problems, from bad feathering spindle, bad seesaw arms, the need for a tail mounted servo, sticky tail slider, the list could go on. I have now finished it and flown it for the first time Yesterday(also, thank you to Finless for the video on setting up a CCPM bird). I fixed and replaced all defective parts, the tail slider no longer sticks, and the main shaft and feathering spindle are strait and new. I am using Align 325mm woodies, and the blades have tracked perfect. I have a tail mounted servo. The first flight was way beyond perfect, no trim required, and very stable, except for a few minor things that I do not know how to fix.....

1. It seems very slugish and slow to respond to control inputs even with expo set to +40 and D/R set to 140%...... to bide my time, I bought a little Blade CP Pro, and it was much more manueverable than the MX450(maybe I am just used to flying that unstable little thing).

2. When I input Forward or Reverse collective, and release it, the helicopter tail "bobs" up and down(not to be confused with yaw left to right)

3. When I input left collective, the blades also pitch forward a fair degree, causing it to pitch forward and left. Not sure why this is happening.

4. I seem to have some kind of glitch where the engine only is affected. If the helicopter sits, no throttle, and no inputs, sometimes at random, the engine will spool up for a split second, and in flight, it completley dies for 2 seconds(almost requiring an autorotation) then starts back up. This was also a problem on the Blade CP, as I put the same radio and receiver in it. I am banking on the receiver, but was wondering if it could be just the crystal, or what your opinions may be.

Thank you all for your help.. I am hooked on Helicopters, and now that I got it to fly, I cant get enough. Some of it is a pain in the butt, like all the problems I ave had, and am having, but I know that It will be awesome once I have it dialed in. Thank you all for your help.....

A new Freak,
Earl "Siconic"

[warpspeed]

Earl, welcome to the Freak!

Couple of things that may help....

Re: #1 & #2, When you say you "release the collective" are you physically letting go of the stick? This may sound strange but these things are so sensitive that when the stick bounces, so does the heli. It may also be a headspeed issue, which would account for the slugishness, so you could try going up a tooth on your pinion and remove the flybar weights.

Re: #3, assuming you followed Bob's vid on CCPM interactions, this could simply boil down to stick movement-I dealt with the same thing for the longest time and finally realized it was my own stupid thumbs moving the stick forward or back when making a turn! This may not be the case for you but something to think about.

Lastly #4. This one should be pretty easy to figure out, will just take a little trial and error. What radio equipment are you using? You could try the usual-reseat the crystal, make sure the antenna is fully extended and away from the motor and esc and their wiring, and go over your connections to make sure nothing's loose or broken. (Which would be my guess)

If I think of anything else I'll let you know, and maybe one of the experts will chime in too.

Good luck!

[siconic]

Thanks for the reply and advice... I rebalanced my blades, and it made a difference in #1 and 2. I also tried what you said about not releasing the stick, and that made it a lot better... such a simple thing to overlook.

I do have another question.... I seem to have a tremendous amount of negative pitch and almost no positive(in flight it gains altitude like a bat out of hell), even when the pitch slider hits the bottom of the head... Not a big deal, just wondering why there is so much more negative pitch than positive.

Point 3, I would have thought that, but I actually have to add back collective to get a turn only... But interaction may be the case... I will investigate that a little better.

Point 4, I turned it on and just let it sit, and I was wrong. All the servos glitch, and the motor spins up... I almost want to try a new crystal, but I will try moving the antena first... I was wondering, could a damaged receiver antena do it? I ruined my tail boom while trying to get the blades to track 5 months ago, and in the process it exposed some copper wire, and broke an inch off the end... I also have it tied in a knot on the end. AFter that is when I noticed the glitching.

Thank you for your post,
Earl "siconic" :D

[warpspeed]

Knots=bad. Sounds like that rascal needs to be replaced but you may be able to get away with just untying the knot and putting a little heat shrink over the exposed wire. Definitely start with that before buying new crystals! If it doesn't help and you've got a LHS nearby it might be worth it to take the heli in and see if they'll let you swap crystals and perform a range check to help identify the culprit.

If its gaining altitude like mad you have too much positive pitch. Could be radio settings but usually if you have one more than the other it's because the swash is not setup correctly. In your case you'll probably have to shorten the links from the servos to the swash, but since you're also getting unwanted control inputs it wouldn't hurt to tear down the head completely and start over-sorry man, I know what a giant PITA that is, but there's no other way around it! Again Bob's vids for the Rex450 explain it better, but basically it boils down to this:

Assuming your servo arms are at 90 deg., set your swash percentage in the radio to 50% and move the collective stick to half throttle. Shorten your servo to swash links a turn or two and check to see if you've got equal distances between the hub and the main shaft collar and that the swash is level. There's a tool for this, but you can get away with eyeballing it or if you have a small triangle place that against the shaft and measure at each ball link. Return the stick to half throttle and work your way up the head making sure your washout arms are level (perpendicular to each other as viewed from the side) and ditto with the seesaw arms. If you've got the plastic links from seesaw to grips, do yourself a huge favor and pickup the links for the Rex 450-it will make fine tuning much easier and blade tracking won't be such a headache.
If you've done this right then you should have the same amount of pitch at full negative and positive-from there it's just a matter of increasing your swash percentage to achieve the amount of pitch you want.

Damn I'm long winded today! Sorry about that!

[siconic]

Awesome... Thanks for the reply once again... I should have stated that the pitch if I set up the radio right is equal both ways,(instead of 0% pitch in the first pitch curve, I have it set to 20%, witch I would assume means I have 20% to much negative pitch at idle) but I did set it up the way the video said. I should ALSO state that the head was in complete peices for the last 4 months and I had no diagram to reassemble it. At center stick, the swash is in the middle, but for some reason the blades do have negative pitch. At full, there is plenty of positive. I must say the heli flies awesome, I have worked out most of the bugs. The only two that remain are the glitch, and tail "bob" (up and down). The tail bob got worse today after some loops, hard turns and high speed forward flight. I think I may have found the culprit however. I wobbled the head where the screw attaches it to the main shaft. Lo and behold, some play. I will try tightening it and see if that fixes it.

Thanks for all the help... Oh and thanks for the tipe on fine tuning the tracking... Yhe tracking is actually almost perfect, except in idle up.. The blades have a little bit of seperation, and that tip would take that out....

Earl, "siconic"