Model Airplane News – September 2019

SEPTEMBER 2019 63

All dirtied up on final: gear, flaps, correct angle of attack, and speed. Jets are fun!

Climbout for the

camera—a very clean-

looking model!

Preinstalled nose gear retract unit. The hole to the
right of the tire is an inlet for battery-cooling air.

As with the wing, all empennage parts are attached
with 3mm machine screws. This makes parts
replacement a snap as there’s no adhesive to cut
through.

BOTTOM LINE

You can plan on spending less than an hour assembling your Viper as there isn’t

that much to build. Eleven screws do the job, with no requirement for adhesives

of any kind. Some experience with electric ducted fan–powered models will

be helpful but not essential. Actual assembly is straightforward and doesn’t

require a lot in the way of tools. This little jet flies remarkably well, is scalelike,

and is very fast using the stock power system. It’s relatively unaffected by

moderate wind conditions (especially if the AS3X system is active) and doesn’t

hold any surprises. It is likely to become one of your favorite sport-scale jets

and is a step up from nearly all the small electric foamies, both in sophistication

and performance. The absolute best part of this jet, beyond what I’ve already

mentioned, is the price. It’s hard to figure how this kit can be sold for less than

$250 given the completeness and quality of the supplied components. Does it

work right out of the box? Absolutely! If you buy the Bind-N-Fly (BNF) version,

just install a 6S 3300 to 3800mAh LiPo pack and bind the receiver to your

transmitter, and you’re ready to go! J

minimized—and it shows, displaying very
predictable flying qualities.
Aerobatics: The Viper easily performs any
scale-type aerobatic maneuver you would
expect of a scale jet model of this type. A
big plus is the level of power provided by
the propulsion system; it doesn’t require
building up a huge head of steam to get over
the top in big, round loops, and it moves the
model along at very scalelike speeds. Rolls
are smooth and fairly axial, and the ailerons,
even in low rate, are effective. Almost no

elevator is required through the revolution.

Slow rolls do, however, look great when

started at one end of the field and completed

at the other.

Glide and stall performance: The model

looks super in the landing configuration and,

if flaps are used, bleeds off speed quickly

after entering the landing pattern. Without

flaps, however, it will carry farther down

the runway. I may try to move the center of

gravity aft slightly by shifting the battery

location to slow it down a bit for “no-flap”

landings. This might make it a bit touchier in

pitch, but expo might be able to easily cure

that.

PILOT DEBRIEFING

Although Horizon makes no claims as to

speed potential, I’m sure 90mph is easily

achievable with the Viper. Since I don’t have

telemetry downlink (yet!), I will say that,

for its size, it appears (and sounds as if)

it’s moving briskly when it is “on the step,”

and other observers have made similar

comments.