# Energy efficiency of Wright model B

Updated Nov 5, 2020

The Wright model B:

• flew around 0.10—0.21m/kJ
• and moved mass at around 0.036 – 0.12 kg.m/J

Contents

## Details

The Wright Model B was a 1910 plane developed by the Wright Brothers.1

### Mass

According to Wikipedia2:

• Empty weight: 800 lb (363 kg)
• Gross weight: 1,250 lb (567 kg)

We use the range 363—567 kg, since we do not know at what weight in that range the relevant speeds were measured.

### Energy use per second

From Wikipedia, we have3:

• Power: 35 horsepower = 26kW
• Efficiency of use of energy from fuel: we could not find data on this, so use an estimate of 15%-30%, based on what we know about the energy efficiency of the Wright Flyer.

From these we can calculate:

Energy use per second
= power of engine x 1/efficiency in converting energy to engine power
= 26kJ/s / .15—26kJ/s / .30
= 86.6—173 kJ/s

### Distance per second

Wikipedia gives us4:

• Maximum speed: 45 mph (72 km/h, 39 kn)
• Cruise speed: 40 mph (64 km/h, 35 kn)

We use the cruise speed, as it seems more likely to represent speed achieved with the energy usages reported.

### Distance per Joule

We now have (from above):

• speed = 40miles/h = 17.9m/s
• energy use = 86.6—173 kJ/s

Thus, on average each second the plane flies 17.9m and uses 86.6—173 kJ, for 0.10—0.21m/kJ.

### Mass.distance per Joule

We have:

• Distance per kilojoule: 0.10—0.21m/kJ
• Mass: 363—567kg

This gives us a range of 0.036 – 0.12 kg.m/J

Primary author: Ronny Fernandez

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