#903018

Viper 989

1/8 scale Gas on road car

The Serpent Viper 989

is the latest development of Serpent on the 1/8 gas market.

Serpent has been the driving force for decades and the Viper 989 is the latest interpretation of a high performance race car based on that experience, combined with the latest insights on weight, weight distribution and flex.

As the inventor of the Centax clutch, the 2-speed gearbox and many other things that are now industry standard, we also integrated some new solutions on the suspension.

Another major point of development was to reduce weight, reduction of vibrations and ease of set-up and maintenance.

Key NEW features

Ultra-narrow

chassis with improved flex characteristics. The chassis is milled dowtn in less load-stressed areas to make it as light as possible and still remain stiff in areas where needed.

We kept the possibility to have a weight in the very bottom which is easily adjustable in it’s position.

At the same time we improved the way it is it mounted to reduce vibrations by using a carbon weight bridge which is mounted in anti-vibration rubbers.

We also have added 2 more locations for another weight, one underneath the engine and another one underneath the servosaver.

The central weight bridge allows the use of max 3 weights

All weights are mounted as low as possible to improve the center of gravitiy The one-piece plastic radiomount is replaced by a 2-piece aluminium construction. It is lighter than the plastic one, and at the same time it improves the flex characteristics and the accuracy of mounting the radioplate.

The rear bulkheads are now also connected to the rearplate to improve the stiffness as well as reduce vibrations.

The bulkheads are machined excessively to get the perfect balance between weight and strength

Their shape now allows the removal of the rear solid axle without removal of the 2-speed shaft and belt

The brake now features a 2.5mm thick disc with improved ventilation and braking stability

The pulley adapter is a much lighter construction for better inertia and improved acceleration

A new shorter

internal gear ratio of 2.4 helps acceleration and increases the active range of the overall gear ratio. Using 19/24 now is almost like 18/23 on the 988.

Also the overdrive has changed slightly to have the perfect rear/front drive balance with ENS and EFRA hand out tires

New side belt tensioners

improve clearance with the engine manifold. It also reduces vibrations on the sidebelt.

Adjustment is easily done on the midshaft

The new super-light

midshaft assembly also acts as adjustable belt tensioner as well as pipe wire holder

The completely new gearbox

has less inertia than the one from the 988. This improves acceleration. Despite being lighter it offers new features to improve reliability and consistanty

A much longer ramp for the roller avoiding locking of the second gear even with excessive wear on the shoes

M4 setscrews for gap adjustment to help keeping the gap constant

2 bearings in the second gear “bell” for better truth of rotation and balance

Easy access for adjustment from the outside

2nd gear adapter is locked in position to avoid binding and deliver constant performance of engine and gearbox

New shaped fueltank

mounted on top of the radioplate.

The new tank is more consistent in adjustment no matter if it’s full or almost empty.

The new tank seal keeps a higher pressure and keep things dry and clean
The cap of the tank is higher to allow even faster refueling.

The volume of the tank is 125cc and needs to be adjusted by the user to perfect volume inside the rules by using inserts

New superlight,
one-piece bumper for improved aerodynamics.

No inserts anymore to keep it simple. Excessive testing of different shapes lead us to this design to have the best balance of front end grip on high as well as low speed and hairpins

New shaped radioplate.

This shape has been found to provide the best flex characteristics

New improved shockabsorbers for the ultimate grip

The single most important new feature are probably the shock-absorbers. A lot of attention has been payed to minimize friction and jamming.

Testing has also shown that a slightly smaller bore works better.

On top of that we payed a lot of attention to the bottom seal. A X-ring and a long bushing provide that extra bit of low-friction sealing that keeps the oil inside and the dirt outside

Redesigned rear flex system

In the 989 we redesigned the rear flex system. We wanted to have a much lighter and more accurate system. We found a lot of improvemnet with 2 linkages next to the fueltank. Flex or no-flex is only a matter of replacing the insert in the radioplate

As an option the 989 offers a heave-damper setup in the front as well as the rear.

In this way it is possible to change heave adjustments more or less independent of roll adjustments.
As an example it is possible to have a very light roll damping combined with a very high heave damping, something which is not possible with a classic suspension.
The third damper can be used to only alter the damping characteristics without a third spring, but also to add a spring to alter spring rates for heave The front and rear heave sets are available as an option.

Other main specs

4wd belt-driven race car
Serpent spring steel axles with quick change system for the wheels
Front and rear spring steel cvd shafts
NSK bearings for the transmission
Low friction belts and ball raced belt-tensioner
Black anodized front shaft with one-way bearings and narrow rear solid axle
super low inertia 2-speed gearbox
Independent suspension with hydraulic low-friction shock absorbers
Ball raced front and rear anti-roll bars

Designed by

Michael Salven

With great help from all team-drivers and 977/988 drivers!