科學好好聽

Roadster 超跑動力實驗室

一個零件,改變整台車的科學。

2026.10.15 發表 · 美國德州 SpaceX McGregor 試驗場特斯拉新一代 Roadster:三種版本,其中一台會「飛」
科學好好聽 Podcast ↗
McGregor, Texas 31.40° N / 97.43° W

拖曳旋轉 · 滾動縮放 · 點選標記,看看零件的秘密↕ 上下滑看控制 ↔ 左右滑轉模型↔ 左右滑轉車子・往下滑看推背感

正在組裝你的 Roadster…

一台車,一堆物理。

選一個版本,或自己拉動零件參數,再按「起跑!」或「點火!」。右下角的「剛剛的改變」會告訴你:你動的那個零件,讓加速、極速、續航、車重和跳躍高度各變了多少。一次只改一個零件,最容易找到原因。「雙車對照」讓你的改裝車和發表會版本(或一般跑車)並排起跑。

操作小抄

拖曳:旋轉視角滾輪 / 雙指:縮放畫布方向鍵:旋轉+ −:縮放Home:回到預設視角空白:暫停 / 繼續

2026/10/15 發表會:已知與未知

版本Performance(可上路・雙座)、Thrust(賽道版・後置冷氣推進器)、Rocket(單座・不可上公路・唯一「能飛」的版本,僅受邀)官方Tesla 官網
0–60 mphPerformance <1.6 s、Thrust <0.9 s、Rocket <0.59 s;現場示範 0.81 s官方宣稱以「扣除 1 英尺滾動」方式計時,未經第三方驗證
動力兩具後馬達,各自驅動一個後輪,各配 8.4:1 行星齒輪、無差速器;合計 >1 MW(約 1,341 hp)、約 1,400 N·m;後輪驅動報導Hagerty 訪談、EVXL 整理
極速 / 續航>230 mph(約 370 km/h)、>300 英里(約 483 km)報導官方未給完整規格表
車重低於 1,700 kg;以鎂、鈦、碳纖維減重報導Electrek、Teslarati
吸地風扇多段式風扇+地面密封,可從車底抽氣,靜止時也能倒吊;發表會畫面顯示約 4,700 kg 下壓力存疑Electrek 認為數字偏高,並估計每個風扇約 20 kW
冷氣推進器10 個噴嘴,高壓空氣瓶位於座椅後方;氣瓶 200 L 或 600 L、壓力約 10,000 psi,推力 >80 kN,各家說法不一說法分歧InsideEVs、The EV Report、Electrek
外型隱藏式頭燈、全寬尾燈、平貼式空力;靈感來自 SR-71 與 F-35;Ano White 航太塗裝、仿太空衣面罩的金色玻璃官方+報導Tesla 官網、Electrek、Teslarati
電池未公布。有報導稱約 150 kWh、4680 電芯未證實本實驗預設 100 kWh,可對應 >300 英里續航
價格 / 量產未公布售價;預約金 Performance 5 萬美元、Thrust 25 萬美元;預計 2028 年量產報導EVXL、The EV Report

模型怎麼算?

每 1/480 秒計算一次牛頓第二定律。後輪能推多大力,取三者中最小的:輪胎抓地力、馬達扭力、馬達功率 ÷ 速度;馬達轉到 23,500 rpm 時由齒輪比決定極速。推進器的推力直接加上去,不經過輪胎,直到氣瓶用完。

m·a = F後輪 + F推進器 − F風阻 − F滾阻
F後輪 ≤ μ ×(後輪負重 + 風扇下壓力的後輪部分 + 加速時的重量轉移)
F後輪 ≤ 扭力 × 齒輪比 ÷ 輪半徑 ・ F後輪 ≤ 功率 ÷ 速度
噴氣時間 ≈ 可用空氣質量 ÷(推力 ÷ 650 m/s)

推估值:車身(不含電池)1,080 kg、駕駛 75 kg、電池每 kWh 6 kg、氣瓶每公升 0.6 kg 外加 0.55 kg 的高壓空氣(約 690 bar)、可用空氣 85%、噴氣速度 650 m/s、後輪靜態負重 56%、輪半徑 0.355 m、迎風面積 1.75 m²、滾動阻力係數 0.013。續航以 110 km/h 定速計算。風扇耗電以每 4,700 kgf 約 80 kW 估算。這些數字讓三個版本接近官方 0–60 mph 宣稱,但都不是特斯拉公布的資料。

發表會的兩個特技

貼牆坡道:車子沿著像半個雲霄飛車迴圈的弧形坡道往上爬,頂端約 21 公尺、幾乎倒過來(約 170°)。特斯拉說底盤風扇最多能產生約 2 g 的吸力,讓車倒著也貼得住;接著冷氣推進器把車推離坡道,前方推進器讓車身沿著車長方向左右翻轉 180°,車子翻正後車頭朝後(朝助跑來的方向)落地。本實驗用「自動駕駛定速」爬坡,檢查三件事:坡道推輪子的力 N = m·v²/R + 風扇吸力 + m·g·cosθ 是否一直大於 0、後輪抓地力 μ×N 是否推得贏重力,以及推進器的空氣夠不夠翻正和剎車。

飛越車隊:車子飛過並排停放的 Cybercab、Model 3、Model Y、Cybertruck 和 4.1 公尺高的 Semi,最高約 7–8 公尺,還在空中桶滾一圈。本實驗用車底噴嘴朝下噴氣起飛,之後是拋體運動;車子的外形會跟每台車的高度比對,桶滾時車身變「高」會吃掉間距。車輛排列順序、間距、坡道寬度與噴嘴配置都是示意,並非發表會實際尺寸。

噴流裡的「馬赫環」

高壓空氣從噴嘴衝出時比音速還快,壓力又比外面的空氣高,噴流會一下膨脹、一下被壓回去,形成一串菱形的震波,叫做「馬赫環」(shock diamonds)。第一個馬赫環離噴嘴約 x ≈ 0.67 × 噴嘴直徑 × √(噴嘴壓力 ÷ 大氣壓)。本實驗假設每個噴嘴直徑 4 cm、推力係數 1.5,用推力反推噴嘴壓力:推力越大,壓力越高,馬赫環越拉開。注意:冷空氣不會像火箭火焰那樣發光,現實中要靠水氣凝結或紋影攝影才看得見;發表會報導也沒有提到。畫面上的亮點是為了教學而標出位置。

聲音也是科學

音效預設是開的(右上角喇叭可以關掉),用耳朵就能「聽」到速度:馬達的高頻聲音,音高跟馬達轉速成正比(轉速 = 車速 ÷ 輪半徑 × 齒輪比),轉到 23,500 rpm 上限時音高就不再升高;風聲大小跟速度的平方有關,和空氣阻力一樣;胎噪只有輪子著地時才有,飛起來就消失;路邊標柱每 10 公尺一支,經過時「咻」一聲,越快越密。電動車本身很安靜,所以各國法規要求低速(例如時速 20 公里以下)時發出提示音,提醒行人注意。這些聲音都是瀏覽器即時合成的示意聲,不是錄下來的真實聲音。

小朋友的表情代表什麼?

香氛吊飾的角度就是「加速度 ÷ 重力」的反正切,和真實車上吊飾的物理一樣。推背感的 g 值是模型算出的水平加速度除以 9.81;表情只是比喻。太空梭升空約 3 g、一般人在雲霄飛車上約 1–1.5 g 水平加速度。

資料與延伸閱讀

Pick a version or move the component sliders, then press Launch or Ignite. The “What your last change did” card shows how the part you just moved changed acceleration, top speed, range, weight and hop height. Change one part at a time to find the cause. Head-to-head races your build against a reveal version or an ordinary sports car.

Controls

Drag: orbitWheel / pinch: zoomArrow keys on canvas: orbit+ −: zoomHome: reset viewSpace: pause / resume

The 15 Oct 2026 reveal: known and unknown

VersionsPerformance (road, two seats), Thrust (track, rear cold-gas thrusters), Rocket (single seat, not road legal, the only “air ready” version, invitation only)Officialtesla.com
0–60 mphPerformance <1.6 s, Thrust <0.9 s, Rocket <0.59 s; 0.81 s shown liveClaimed1-ft rollout timing, not independently verified
PowerTwo rear motors, one per rear wheel, each with an 8.4:1 planetary set and no differential; >1 MW (≈1,341 hp), ≈1,400 N·m; rear-wheel driveReportedHagerty interview, EVXL
Top speed / range>230 mph, >300 milesReportedNo full spec sheet yet
MassUnder 1,700 kg; magnesium, titanium, carbon fibreReportedElectrek, Teslarati
Suction fansMulti-mode fans plus ground seal pull air from under the car, enough to hang upside down while stationary; on-screen readout ≈4,700 kgDisputedElectrek doubts the figure and estimates ≈20 kW per fan
Thrusters10 nozzles fed by a compressed-air tank behind the seats; 200 L vs 600 L, ≈10,000 psi, >80 kN reportedConflictingInsideEVs, The EV Report, Electrek
DesignHidden headlights, full-length taillight, flush aero; SR-71 and F-35 inspired; Ano White aerospace paint, gold visor-style glassOfficial + reportedtesla.com, Electrek, Teslarati
BatteryNot announced; one report says ≈150 kWh with 4680 cellsUnconfirmedThis lab defaults to 100 kWh, matching >300 miles
Price / productionNo price; deposits $50,000 (Performance) and $250,000 (Thrust); production planned for 2028ReportedEVXL, The EV Report

How the model works

Newton's second law, every 1/480 s. The rear tires push with the smallest of tire grip, motor torque and motor power ÷ speed; at 23,500 rpm the gear ratio caps the top speed. Thruster force is added directly, bypassing the tires, until the tank is empty.

m·a = Frear + Fthrust − Fdrag − Frolling
Frear ≤ μ × (rear load + rear share of fan downforce + weight transfer)
Frear ≤ torque × gear ÷ wheel radius · Frear ≤ power ÷ speed
burn time ≈ usable air mass ÷ (thrust ÷ 650 m/s)

Estimates: body without battery 1,080 kg, driver 75 kg, 6 kg per kWh, tank 0.6 kg per litre plus 0.55 kg of air at ≈690 bar, 85% usable air, 650 m/s exhaust, 56% static rear load, 0.355 m wheel radius, 1.75 m² frontal area, rolling coefficient 0.013. Range is a steady 110 km/h cruise. Fan power is ≈80 kW per 4,700 kgf. These values bring the three versions close to Tesla's 0–60 claims, but none of them are Tesla data.

The two reveal stunts

Wall ramp: the car climbed a curved ramp shaped like half a roller-coaster loop to about 21 m, nearly upside down (about 170°). Tesla says the underbody fans can pull up to about 2 g, so the car sticks even inverted; cold-gas thrusters then pushed it off and front thrusters rolled it 180° about its length, so it came down upright facing backwards, toward where it started. This lab climbs at a constant autopilot speed and checks three things: whether the ramp keeps pressing on the wheels, N = m·v²/R + fan suction + m·g·cosθ > 0; whether rear-tire grip μ×N can beat gravity; and whether the air lasts for the flip and the braking burn.

Fleet jump: the car leapt over a parked Cybercab, Model 3, Model Y, Cybertruck and the 4.1 m Semi, peaking around 7–8 m, with a barrel roll. Here the down nozzles lift the car, then it follows projectile motion; the car’s outline is checked against each vehicle’s height, and rolling makes the car taller and eats into the gap. Vehicle order, spacing, ramp width and nozzle layout are illustrative, not the reveal’s exact dimensions.

Mach diamonds in the jet

Compressed air leaves the nozzle faster than sound and at a higher pressure than the air around it, so the jet expands, gets squeezed back, and repeats, forming a chain of diamond-shaped shock waves. The first one sits about x ≈ 0.67 × nozzle diameter × √(nozzle pressure ÷ atmospheric pressure) from the nozzle. This lab assumes 4 cm nozzles and a thrust coefficient of 1.5 and works the nozzle pressure out from the thrust: more thrust, higher pressure, wider spacing. Cold air does not glow like a rocket flame; in real life you only see the diamonds through condensation or schlieren photography, and the reveal coverage does not mention them. The bright beads mark where they would be.

Sound is science too

Sound is on by default (the speaker button turns it off), so you can hear the speed: the motor whine rises in pitch with motor rpm (rpm = speed ÷ wheel radius × gear ratio) and stops rising at the 23,500 rpm limit; wind noise grows with speed squared, just like air drag; tire roar is there only while the wheels touch the ground; and each roadside post, one every 10 m, goes “whoosh” — faster speed, faster rhythm. Electric cars are so quiet that the law requires a warning sound at low speed (for example below 20 km/h) so pedestrians notice them. All sounds are synthesized live in the browser for illustration, not recordings.

What do the faces mean?

The air freshener hangs at arctan(acceleration ÷ gravity), exactly like in a real car. The g number is the model's forward acceleration ÷ 9.81; the faces are just a metaphor. A Space Shuttle launch peaks around 3 g.

Sources and further reading

科學好好聽與特斯拉公司無關;Tesla 與 Roadster 為 Tesla, Inc. 的商標。