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The 3DX450 (also sold under the name HDX450) is a range of helicopters manufactured by Sonix. It comes in three variants (A, B, and F) which primarily differ in the design of the airframe; most mechanical components including the head and the tail are identical. Possibly the most common variant is the B. The frames are also available in different materials: glass fiber, silver carbon fiber and black carbon fiber. The head and tail are made completely of alloy, and ballraced.

Known issues

The main mast features a flat spot to help retention of the mast collar, however some replacement shafts have a lip in just the wrong position, and must be ground off before use.

The tail pitch slider has been produced in two variants, one using leading edge control and one using trailing edge control. Leading edge control gives a far more useful tail pitch range.

The tail rotor hubs have been known to be mis-machined and cause unacceptable levels of vibration.

When using the alloy tail drive pulley, it is possible for the pulley to lose its grip on the tail shaft (as it's secured only by two grub screws. It is advisable to grind two small flats onto the tail shaft to give the grub screw better grip.

The bearings in the Bell-Hiller mixer arms are prone to becoming sloppy in a crash, leading to poor collective pitch control. It may be cheaper to replace the entire arm rather than than just the bearings.

The washout arms wear relatively rapidly.

The battery tray on the 'B' version is poorly supported in the event of a crash, and may bend. The end of the frame proper protrudes above the battery tray, and can easily dent batteries in a crash.

T-rex main masts have marginally too large a diameter to be used with a new swashplate and washout.

Some batches of the metal landing gear may be mis-drilled and not match the mounting holes on the helicopter (it also bends relatively easily). The plastic landing gear works fine.

The obvious gyro mounting point, above where the tail boom is held in the frame, has a big hole in it where the gyro would mount. There is no obvious way to mount the gyro below the tail boom.

It appears that the feathering spindle and tail boom from the Beam E4 may be usable on the 3DX450.

External links

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