Racecar Engineering – September 2019

18 http://www.racecar-engineering.com SEPTEMBER 2019

FORMULA 1 – TORO ROSSO STR

everyteam;youinvesta lotoftimeandmoney

andyouwantit alltowork.’

Withthemethodologyofhowthe

racecarwouldbedeveloped,adjustedand

potentiallyimprovedset,attentionturnedto

thedesignitself,andthepreviouslymentioned

shortcomingsoftheSTR13.‘Wefeltthatthe

operatingwindowoflastyear’scarwasnot

bigenough,it wasdifficulttosetupandon

occasionit wasdifficulttodrive,’Egginton

says.‘WiththeSTR14wewantedtoopenthe

operatingwindowandgivetheengineers

morefreedom.Wewantedtoallowthemto

setthecarupwithoutsufferingthenegative

impactofanaeromapwhichwasperhapstoo

sensitiveorpeakyina highyawcondition,

or[ofhaving]a rearrideheightcharacteristic

thatperhapsmeantthatyouhadtorunthe

rearendstifferthanyouotherwisemighthave

wantedina smallrideheightrange.

‘Sothechallengewastoexpandallofthat,

whichcancostyouperformance.Weespecially

wantedtoimprovelowspeedperformanceas

well.Thenontopofthatwehadtheregulation

changesoactuallyonpaperallthethingswe

weretryingtodo,allthechangeswewere

making,werea littlebitscarybecausewewere

notsurehowwewouldrecoverthelossesfrom

thechangesinthefrontwing,forinstance.’

Aeroconcerns

The 2019 aerodynamicregulationchanges

meantworryfortheSTR14designersbecause

a keyobjectiveofthecar’sdesignwastomake

it asadaptableaspossible.‘Wedevelopedthe

conceptofthecartogiveusasmuchfreedom

aspossibletodevelopandaddperformance

withouthavingtomakebackground

architecturalchanges.Wehavea development

pathforourcarinthewindtunnel,butat

Chassis

Mouldedcompositemonocoque.

Engine

HondaRA619H(seepage26).

Transmission

RedBullTechnologies(2018specification)composite

casingwithXtracinternals;eightforwardgears,onereverse;

multi-platecarbonfibreclutch.

Suspension

Unequallengthcarbonfibredoublewishbone,withpushrod actuated

torsionbars(front),pullrodactuated(rear);Inboardfrontparts and all

rearcomponentssuppliedbyRedBullTechnology.

Brakes

Carbon-carbonwithBrembocalipersto ToroRossodesign.

Tyres

Pirelli.

Weight

743kgminimum(80kgdriverminimum).

TECH SPEC: Toro Rosso STR

‘The operatingwindow of last year’s car wasnot bigenough,

it was difficult to set up and on occasion it was tricky to drive’

a Renaultpowerunit,yettheToroRossois

Honda-powered.TheFrenchandJapanese

unitshavesignificantlydifferentshapes,with

thelatterusinga splitturbochargerlayout,

withthecompressoratthefrontoftheblock,

whiletheRenaulthasa conventionaldesign

withcompressorandturbineattherear.This

any given moment one change can lead to

something else and that can lead you down

a different avenue,’ Egginton says. ‘We are not

really in a position where we can bring complete

update packages to change our direction

and that means we have an evolutionary

development approach, rather than revolutions.’

Bull market

One way that Toro Rosso reduced the level of

uncertainty with certain areas of the STR

design was to revise its model of what is made

in house and what is bought in. For many years

the team has prided itself on having bespoke

transmissions, even when Toro Rosso used

Ferrari-engined versions of Adrian Newey’s Red

Bull Racing chassis it persisted with its own

gearboxes. That has all changed in 2019, with

many parts of the STR14 being supplied by Red

Bull Racing including the gearbox, making the

STR14 the first car in many years to come out of

the Faenza factory without a bespoke casing.

‘The rear end has been provided by Red Bull

Technology. We are taking a gearbox casing and

rear suspension although many of the internals

of the gearbox are similar to parts we have used

in the past,’ Egginton says. ‘It’s a bit of a mix of

parts, the rear end of the car, the gearbox casing

and the main suspension parts are from the

Red Bull RB14 [the 2018 car]. The time-scales

for using RB15 [the 2019 car] parts were not

really compliant with our timetable, our design

process and timing is different to them, as is our

car build. But the RB14 parts are fine, there is no

compromise there, it just made more sense to

use them. They are a known quantity.’

Using the Red Bull RB14 gearbox gives

the STR14 a composite casing, with internals

from Xtrac. However, a key issue with the

2018 ’box is that it was designed for use with

Red Bull RB14 gearbox was designed for use with a Renault engine, but it also fits the Honda in the STR

Rear suspension, brakes and uprights all come from the RB

Many RB14 front suspension parts are also used on the STR