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Old Mar 15, 2007, 03:55 PM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
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Discussion
The Official MX450XS with general 3X-4X-5X+ size shop talk / bring your coffee cup!

I'd like to start this thread if I may.
But anyway I'd like to hear from you (fellow pilots) your impressions, experiences, experiments, conversions, modifications, tips, radio setups, and bring it on in full detail, got pics and video links post them here for all to see and learn.

Also this thread is open to any kind of heli discussion from a tiny coax to the largest heli made short of riding in it

Blog 1

Blog 2
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Last edited by Rollingball; Mar 14, 2008 at 08:23 AM.
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Old Mar 15, 2007, 08:40 PM
Registered User
Fort Collins, CO.
Joined Sep 2002
457 Posts
I have one on the way. should have it by monday, I hope. cant wait.
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Old Mar 15, 2007, 09:10 PM
Authorized Self-Portrait?
kitfoxdrvr's Avatar
Greensboro, NC
Joined Nov 2003
1,060 Posts
Look forward to your thoughts; I have the MX400 with most of the red metal added through attrition of the plastic (due to numerous impacts with terra really firma). I think you will like it! What motor/esc/bec/battery/servo/gyro setup are you using?
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Old Mar 16, 2007, 05:22 AM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
Currently on my wish list:

WL is now empty time to fly.....
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Last edited by Rollingball; Apr 29, 2007 at 05:11 PM. Reason: Tips and Advise makes the W.L. a work in progress
Old Mar 16, 2007, 10:47 PM
Psurvival = 1/ThArrival
osterizer's Avatar
Maryland, USA
Joined Jan 2007
8,577 Posts
Well, you asked for it . This is long, but it describes my initial experience with the 450. I came to the forum looking for info on it, but the only thing I found was the ARK400 thread, so thank you for starting this one. Since I was looking for info, I guess the best way to start is to share some. Enjoy.

The following are a bunch of notes on my new MX450. I just got it put together a week ago. I have only flown it a few short hops after assembly to get familiar, but it seems a great next step after my others: CoCo v3, PicooZ, Honey Bee FP, and a modded/tuned Blade CP Pro that I still have a great time with. I'm very happy with the MX450, with some reservations, particularly about the "ARF" label applied to any heli-- almost ready to trim/adjust/tweak is more like it.

I used a lot of the recommended parts since it's my first 400: S3107s on the head, the ammo motor, and HeliMax ESC. I used a GY401 and S3154 for the tail instead of the S3107/GY240, and GP Power Series 2100s instead of the recommended generic battery since the PS comes with a balancing connector that mates to my Equinox balancer/interface-- really good setup with the Triton charger if you have a few batteries. The PS batteries also have a higher discharge rate and are almost identical in size to the recommended one.

Out of the box, mine was not almost ready to fly, but this is not a bad thing-- no helicopter is almost ready to fly unless it has been completely assembled, trimmed and flown before you even see it. On this one, about a third of the screws were loose, and the tail belt was very loose. The tail blades were rough in the grips because they had a lot of flash/molding ridges on them, but a few minutes with a screwdriver and sanding block took care of both concerns. I also matched (balanced) the tail blades, and took apart the tail hub and made sure everything moved smoothly, oiled the slider and shaft with WD40, and put it back together.

All I needed to do with the head was adjust the servo links for static level and to trim it slightly; you set the links to the length given in the manual, but you still need to at least verify that travel and trim are right. Some of the screws in the head were loose, too, but you'll catch that if you go over the whole heli and test every screw to start with as you should.

One of my blade grips was not drilled correctly (too small), so the blade hinge bolt would not go in-- unfortunate, but the rest of the head is so incredibly smooth and tight.... I bored the grip a little and everything's hunky dory now. The head motion out of the box was a little stiff, but after 15 minutes runtime it is working beautifully: no slop and no drag, just a great little piece of machinery.

The part I liked the least was the main blades-- completely, totally, far out of balance. If it will work I'm going to ditch them for a set of TR CF blades. Once balanced the glass blades seem ok, but I don't like to rely on blades that take a lot of tape.

For the radio, I used the Futaba R146iP that was recommended, talking to my 9CAP/S transmitter in PCM. I know, the AP is the fixed-wing version, but I've had it for a long time for my fixed-wings, and it works well for powered fixed-wing, sailplanes, and helis; in fact, most of the txs that come with the RTF helis are identical to those in RTF planks, but with CCPM, so it's becoming a pretty common setup. The 9C is smooth as glass, has four throttle and pitch curves, gives complete programmability for helicopters, and a synthesized module so I can switch freqs to match all of my helis. What's not to like? The Spektrum has a way to go before it will match what you can do with a 9C, even with the appeal of the DSM2..

Having it to do again, what would I change? The ESC, no doubt; the HM 40A is appropriate, and I can get a good hover with it, but the soft start isn't soft at all (others have commented on this as well), and it's putting stress on the aircraft that isn't appropriate. I'm going to get a Phoenix this weekend and see how that compares, because the HM ESC torques the bird around 180 degrees when it starts the rotor-- very bad. Also, I put the main servos in with the standard arms and the balls in the outermost holes; they seem to work well up to about 10 degrees of pitch, but you run out of control after that; I'm going to change them out for some longer ones.

Since you add your own motor, radio, ESC, and gyro, you have to follow the instructions for each of them for setup. As I said, the HM ESC in both modes doesn't work the way I like it, but I followed the instructions.

The GY401/S3154 combination, set up by the book, worked out of the box better than I would have imagined-- Futaba gear is a little more expensive, but it's worth it! I mounted the servo in the frames as described in the manual, electronically centered it, and then adjusted the pushrod for zero pitch on the tail. The gyro limits matched the physical limits of the tail slider without any adjustment, or I would have gotten a boom mount for the servo and replaced the steel pushrod with a shorter CF one. I may do this anyway since I hate the idea of the steel pushrod rattling in the aluminum stab mount, but we'll see if it's really a problem.

I spent about four hours setting up the pitch curves and travel for the servos in normal, idl1, and idl2, and in the swash afr volumes in the 9C. I have the rotors set to -2 to +10 in normal, and -10 to +10 in idle ups, with idl1 going to 85% throttle in the middle to transition from normal, and idl2 set to 100% flat. Normal throttle is linear. I haven't tried the idle ups yet because the weather has been nasty, but the normal curve worked fine so far.

Which brings us to flying, which as I have said, has been limited to date for me. I come to the 450 from a Blade CP Pro with a lot of modification and tweaking-- the Blade is a tiny, aerobatic, low mass, difficult little heli; it's a blast to fly, but the 450 is a completely different experience. Bring the throttle up to start the motor, ignore the spin until the rotors and tail get speed enough for authority, then turn to tail in. Increase the throttle to bring it off the ground, a little right cyclic to keep it centered, then up to about 10 feet altitude. The GY401 keeps the tail perfectly planted, and with the recommended pitch you have plenty of control. Trimming is no problem if you adjusted the swash well statically. I used the same -10% expo that I do with the Blade, and with that I had a hover first time out that was just hanging motionless in the air. I really like this heli . More notes after I've shoveled the global warming off the driveway and I can fly around a bit.

Lessons learned? Some, some recaps:

-- don't use the HM ESC. We'll see how the Castle one works, or maybe someone else has a better idea.
-- don't stick servos/motor/radio in and go fly; there is no such thing as an ARF heli. I may get flamed by a TRex fan for this, but if you get an SA and don't do exactly the same disassemble, check, adjust and trim process I described, you're far too trusting. These guys are too powerful not to check everything.
-- get good equipment; the Futaba gear I put in mine works perfectly. Use a mishmash and your mileage will vary.
-- bin the stock blades. A lot of people have reported that they suck, so I'm looking around, and the Align 315s are first on the list.

The MX450 is a very nice heli-- it fixes all the problems I had with the BCPP, and adds a lot of value over what you'd get from a TRex at the same price. That said, I've seen a lot of discussion about upgrades, particularly swapping the tail unit for the TR parts, but we'll see. Once I get some solid flying time with it I'll probably want to change something else, but I haven't gotten there yet.

Hope you find this useful.

billr

[Edit] Almost forgot to mention this; I had a pretty interesting head vibration when I first spun it up, and I found that the Jesus bolt was still loose. I would have sworn I checked that, but anyway.... Tightening it up got rid of most of the vibration in the a/c, but not all. My intuition is that the remainder is from the bad rotor blades, but we'll see what happens after I swap them out.
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Last edited by osterizer; Mar 16, 2007 at 11:24 PM.
Old Mar 17, 2007, 09:53 AM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
WOW -- osterizer-- great information on your current setup.
I'll be printing this one out and I'll have to read a couple of times to take in all the information.
I thank you for describing every little detail, it makes life easier, when I get to final assembly and test flights

I'll be redoing every screw and bolt with thread-locker and looking for burrs and such.

Keep us informed on your progress and further developments.
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Old Mar 17, 2007, 03:11 PM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
Made one of my improvements:

Swapped the plastic belt drive pulley to aluminum pulley.

Part# HS1203 Metal Tail Rotor Shaft from Align

Also tightened all screws with thread-locker (lots of marginal factory assembly) mostly in the tail case and frame - none in the head.
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Last edited by Rollingball; Mar 18, 2007 at 02:41 PM. Reason: Part # Correction
Old Mar 17, 2007, 03:59 PM
Registered User
Joined Feb 2006
960 Posts
I have used the ark x400 CF stretched a while back its virtually the same thing except the plastic head. I found it to be an excellent heli. And I found the gearset to be far better then the align one. Much tighter fit and less wobbly.
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Old Mar 17, 2007, 06:03 PM
Psurvival = 1/ThArrival
osterizer's Avatar
Maryland, USA
Joined Jan 2007
8,577 Posts
Quote:
Originally Posted by Rollingball
Made one of my improvements:

Swapped the plastic belt drive pulleys to aluminum pulleys.

Part# HS1153T from Align

Also tightened all screws with thread-locker (lots of marginal factory assembly) mostly in the tail case and frame - none in the head.
Nice, but educate me, please-- what's the improvement of metal pulleys over plastic?

I did get the Phoenix and put it in-- much nicer, but omg it has a lot of options available for programming! I'm reading the docs that came with it-- more than came with the gyro --and deciding what I'm going to do with it .

Swapped in some TRex blades, also, and it doesn't wobble spooling down any more, but they're impossible to see in lower light so I put some white tracking tape at the tips. The difference won't be really obvious in flying, but it will cut down on vibration and make the batts and heli last longer so I feel better.

Why can't we just buy a heli and fly it, instead of tweaking and fiddling with it? Is it some kind of genetic defect, an acquired disease, or just a character flaw?
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Old Mar 17, 2007, 06:29 PM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
I think I saw this topic somewhere in the X400 thread, where some of the pulleys were distorting/stripping and melting maybe from too tight of a belt, but anyway I rather be safe than sorry, especially when it comes to the operation of the tail rotor.

The Esc that runs the tail motor on my Axe has all kinds of programmable features and the one that runs the main motor has only one feature.
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Old Mar 17, 2007, 06:41 PM
Psurvival = 1/ThArrival
osterizer's Avatar
Maryland, USA
Joined Jan 2007
8,577 Posts
OK, thanks-- I was thinking for better precision, but I'd expect the belt would soak up any vibes from inconsistent gears. I'll keep an eye on them.
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Old Mar 18, 2007, 08:13 PM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
While roaming around heli world via internet went to Helidirect.com (lots of TRex parts) anyways they have a MicroHeli CNC Pulley/Hardened SS Tail Shaft, the shaft is 3-mm dia. and the pulley is a set screw design, that pulley will find a new home on the counter gear to replace the plastic tail pulley
If I found this site sooner I would have got 2, one to put where it belongs and the other to hack parts off of it.

Made a part # correction in previous post for tail rotor pulley replacement.

Another site had CNC upper and lower main gears for TRex but the gear ratios and counter gear match along with the counter gear spacing won't work for the 450xs (bummer)

Also ordered a Great Planes Ammo 28-45-3600 Brushless In-Runner Motor, decided to get the bigger motor from the 2700 but it's still in the recommend K/RPM range. I'll Start with a 11T pinion for a 2707 head speed.
Also got a Heli-Max Aluminum Gyro Mount for the future gyro.

More to come
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Old Mar 19, 2007, 02:03 PM
Back Yard Flyer
Power Up's Avatar
Northern Ontario
Joined Mar 2007
1,587 Posts
Power transition faulty

Great to see this thread on Heli-Max.
I'm kinda new to the Heli hobby. I have the Pro Combo and ran into a problem yesterday. On spool up my motor and main gear seem to rotate ok, but there was a whizzing type sound and no rotar rotation.
I powered off and after several more attempts kept getting the same result. This is only my tenth outing with this heli. Sounds like something is slipping.
I realize there is a one way bearing pressed into the main gear, could this be the problem?
Any possible solutions would be much appreciated.
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Old Mar 19, 2007, 02:09 PM
Psurvival = 1/ThArrival
osterizer's Avatar
Maryland, USA
Joined Jan 2007
8,577 Posts
Kind of simplistic, but is the motor turning the right direction? Sorry, had to ask. If the gear's turning the right direction, then yes, I"d check the auto clutch and the jesus bolt-- i.e., if the mainshaft is turning and the head isn't the bolt might have come out. If the gear's not turning, check the setscrew in the pinion gear. All I can think of right now.
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Old Mar 19, 2007, 02:28 PM
Trial&Error - Repeat
Rollingball's Avatar
Amsterdam, New York
Joined Feb 2007
3,270 Posts
Even though the one way bearing is factory lubed the movement was kinda funky. So I took some Quantum Hot Sauce Fishing Reel oil and shot up the bearing. Now operation is smoooth and it might last a tad bit longer, did the same for the tail pitch slider.
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