Model Airplane News – September 2019

62 ModelAirplaneNews.com

E-FLITE/HORIZON HOBBY VIPER 70MM EDF JET

GEAR USED

RADIO

Spektrum DX6 (spektrum

rc.com), AR636A receiver

(installed on the BNF version); mini

servos installed in the airframe

MOTOR

E-flite 70mm w/ 2860Kv

brushless motor and 70A speed

control w/ BEC (installed)

BATTERY

Spektrum Smart 6S 3200mAh

LiPo

Th ings get a little tight in the equipment compartment, but everything fi ts. Th e new
Smart Technology LiPo performed well.

Four of the six wing attachment screws. Tail installation is similar—no adhesives
required.

Th e underside of the port wing showing retracts, servos, and linkages. Everything

shown is preinstalled.

I marked the wing with the recommended balance point for a center-of-gravity

check. With the battery location I was using with the Smart battery, it was slightly

nose-heavy, which was easily corrected.

nicely hug the surface contours. Th e scheme
itself is a fantasy scheme, never having been
worn by any actual Viper, and I expect the
model will see some interesting and exotic
paint jobs by the makeover crowd.
Th e included assembly manual is well
illustrated and complete. It includes all the
instructions you’ll need to assemble and set
up your Viper, including details on how to set
up the SAFE function and AS3X stabilization
system. Personal preference caused me to
opt out of the SAFE option, but my previous
experience with the AS3X feature on other
E-fl ite off erings allows me to validate the
value of its use.
Th ere are a few things that you should
know about if you are a relative newcomer
to this type of model and are considering
getting one of your own. A great deal of
thought went into the actual design of the
airframe and the component integration,
such as the inlet ducting, fan placement, and
hatch attachment. It’s a great-fl ying model
without the typical shrill, high-pitched sound

we’ve come to expect from traditional low-

blade-count (fi ve or six) rotors; 12 blades do

the trick here. Th is quiets things down and

actually creates a sound more like a turbine

than a dog whistle. Th e model employs the

70mm E-fl ite fan unit driven by a 2850Kv

brushless motor. Coupled to a 6S LiPo

feeding through a 70A speed control, this

unit delivers sparkling performance in the

Viper.

Th e winglets add to the plane’s “swoopy”

looks and are integrally molded into the

wing. Th ey may be susceptible to damage,

however, from loading or unloading from

your car rather than actual fl ight operation,

so be careful.

Th e preinstalled electric retracts are

rugged, but the strut wire, especially for the

nose gear, seemed a bit soft. Keep that in

mind if you fl y off grass fi elds.

IN THE AIR

I balanced my model 3 1/2 inches behind the

wing cutout on the fuselage, and that seems

to be its “sweet spot.”

Stability: Th e Viper’s proportions hint that

it’s going to be very stable, and you won’t be

disappointed.

Tracking: Th e model tracks true throughout

nearly all maneuvers. Given that it’s a

prebuilt, molded-foam almost-ready-

to-fl y plane, the likelihood of warps is