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01-28-2007 04:57 PM  10 years agoPost 1
spr250

rrNovice

Superior, WI USA

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I have a nexus 30 that I bought, but never seen air with me yet. So unless I can get help here since no one where I live can help my bird will collect dust or worse yet I'll crash hard. I need help in setting up my pitch settings for my main and rear blades and how to setup my controller, which is a Futaba 6h. If this helps, it has a Heli Max Rate Adjuster and Heli Max Dual Rate Ball Bearing Gyro. I am pretty stubborn so if I can't get help by early spring, I just may have to bury the bird after its death. So Please help my Nexus stay alive. Also, what size blades does it take, 530 or 550 MM

Pay your taxes on time, I need a raise

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01-28-2007 05:31 PM  10 years agoPost 2
mikeflyz

rrApprentice

Westlake Village, CA

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Just a fair warning, hope you didn't spend a lot on all of that. Unfortunately, everything there is pretty obsolete. What is available now is much better in terms of ease of use, setup, longevity etc.

But if you're absolutely determined to get an old Nexus with vintage gear in the air for nostalgic reasons, it can be done; it just won't fly as well as a nice Raptor or similar with new gear.

Make sure that your receiver battery is up to the task. The gyro you have will have a tremendous drain on it since it is a mechanically powered gyro. Setting up the tail rotor pitch curve for it will be kind of trying and no matter what you do, it won't match the performance of a good modern heading hold gyro.

I have not setup a 6VH for any kind of aerobatic performance, but I think this will at least get it hovering and in forward flight.

You'll want to set up your collective pitch servo so that when the throttle is in the middle, the collective pitch compensator is in the middle of its travel. The links from the swash to the rotor head should be adjusted so that you get your pitch range you need (-3 to +9 degrees). If there is insufficient or too much travel, you'll need to adjust the pots that are covered by the smoked plastic cover for channel 6

You will also have to enable the revo mixing on the tail rotor so that in the hover, (about 2/3 stick), you have some positive pitch on the tail rotor blades and the tail rotor should automatically increase pitch with increasing throttle and decrease pitch with decreasing throttle. Final work is by trial and error.

If you're just learning, you will be better off with a new system. The frustration level will undoubtedly be high and the capabilities of the heli low. Don't just think that you can solve all of the problems by making one or two token upgrades like a gyro etc. That could be compared to putting a microwave oven in a cave.

The Nexus/Concept tail rotor driveshaft system is not very good at all. The flight controls for the main and tail rotors are usually slop filled, and when you do crash, it will be essentially impossible to find replacement parts.

Any of the 30 sized birds will run 550s no problem.

Mike
MA Fury Extreme, JetCopter SX

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01-29-2007 05:33 AM  10 years agoPost 3
dkshema

rrMaster

Cedar Rapids, IA

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The Nexus isn't that bad of a ship. In spite of what you've been told, the tail rotor system on the Nexus and the Concepts worked pretty well and pretty reliably.

Sure, the Nexus isn't a Raptor, but then it was designed many years before the Raptor came on the market. You don't have a Raptor, so let's not pretend you do, or that you want to go out and buy one.

I believe the Nexus rotor blades are 530mm. An extra 20 mm on the Nexus may not be a good idea, you'll need to do some measuring to make sure the longer blades won't whack the TR blades. In TODAY's crop of 30 sized machines, 550s are the norm. But when the Nexus was designed, that wasn't the case.

The Futaba 6H radio should get your Nexus in the air and make it flyable, though the 6H wasn't that great of a heli radio to begin with.

Do make sure that the batteries in both the transmitter and receiver pack are new and usable, that's a must. You don't say how old the radio is, but Nicads don't last forever, especially if not well-cared for.

Assuming you have all the parts, the heli is properly assembled, and set up, it will fly pretty well. I owned three of them a few years back, they never let me down. Parts a bit harder to locate these days, but there are a ton of Nexus helis for sale on Ebay, so parts can still be had.

If you want to resurrect this bird and get it flying, the best short term thing you could do for yourself is to dump the mechanical gyro. Since the Nexus has a wire driven tail rotor, I would suggest that you replace your current mechanical gyro with a Futaba GY240 (run in Normal mode, not Heading Hold mode). Heading hold gyros are a bit tough on the small diameter wire-drives as the Nexus, as the wire is a bit springy and can "wind up" a bit. A heading hold gyro can wreak havoc on that small diameter wire, and cause sudden failure, if not erratic behavior. The GY240 in normal mode (set by a switch on the gyro) would be an inexpensive, yet worthwhile addition to your Nexus.

I'll assume you have an OS 32 SX-H on this heli, it's a good engine for the Nexus and runs fine.

There are a lot of Nexus still flying, and you'll find a bunch of them here. They do fly well and will take you a long way into helicopter flying provided you can keep getting parts.

The Nexus should be able to pull at least -5 to +12 degrees of pitch, that's the range the manual seems to use in the setup information.

You should easily be able to get -5 to +9 degrees which will get you into loops, rolls, and even inverted flight.

Clean it up, get your Nicads healthy, replace that ancient mechanical gyro with a Futaba GY240 run in normal mode, go fly.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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