99 year old aeroplane with 3 horsepower takes flight!

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Aviator168

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I would like to find out what the max take off weight is. If that thing can fly like that, a 20hp engine put on a ultralight can definitely fly much better.

P.S. I think I heard someone in the crowd said it used 2000ft of runway.
 

challenger_II

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I believe the Wren has 8hp, rather than 3hp.

Per Wikipedia:

Survivors[edit]
The sole surviving English Electric Wren (G-EBNV) flies occasionally at the Shuttleworth Collection at Old Warden and is powered by an ABC 8 hp engine. With barely enough power to maintain flight the aircraft is assisted into the air by a team of volunteers using bungee cord, after which the Wren lands straight ahead following a short 'hop'.[2]

Specifications (ABC 8 hp)[edit]
Data from Lumsden[3]

General characteristics
Components
  • Valvetrain: Overhead valve, two valves per cylinder
  • Fuel system: Carburettor
  • Fuel type: Petrol
  • Cooling system: Air-cooled
Performance
 

Aviator168

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I can replace that engine with a Hirth 23 50hp 2 stroke, and it will weight a few lb more. Still meets part 103 requirement, but with much better performance. :)

This is plane's spec
General characteristics

  • Crew: 1
  • Length: 24 ft 3 in (7.39 m)
  • Wingspan: 37 ft 0 in (11.28 m)
  • Height: 4 ft 9 in (1.45 m)
  • Wing area: 145 sq ft (13.5 m2)
  • Empty weight: 232 lb (105 kg)
  • Max takeoff weight: 420 lb (191 kg)
  • Powerplant: 1 × ABC 8 hp 2-cylinder air-cooled horizontally-opposed piston engine, 8 hp (6.0 kW)
  • Propellers: 2-bladed fixed-pitch propeller
Performance

  • Maximum speed: 50 mph (80 km/h, 43 kn)
  • Endurance: 1 hour 30 minutes
  • Rate of climb: 180 ft/min (0.91 m/s)
 
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Vigilant1

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I looked up the wiki. It has an 8hp engine instead of 3hp posted on the youtube video. The interesting thing is. It has a cantilever wing and meets part 103 requirement.

General characteristics

  • Crew: 1
  • Length: 24 ft 3 in (7.39 m)
  • Wingspan: 37 ft 0 in (11.28 m)
  • Height: 4 ft 9 in (1.45 m)
  • Wing area: 145 sq ft (13.5 m2)
  • Empty weight: 232 lb (105 kg)
  • Max takeoff weight: 420 lb (191 kg)
  • Powerplant: 1 × ABC 8 hp 2-cylinder air-cooled horizontally-opposed piston engine, 8 hp (6.0 kW)
  • Propellers: 2-bladed fixed-pitch propeller
Performance

  • Maximum speed: 50 mph (80 km/h, 43 kn)
  • Endurance: 1 hour 30 minutes
  • Rate of climb: 180 ft/min (0.91 m/s)
I dunno. The engine is adapted from a motorcycle where it is claimed to make 8hp at 4500 RPM. I don't think that engine is turning that direct drive prop on that airplane at anything close to 4500 RPM. Plus, if we correct for prop efficiency (maybe 70% at this low airspeed?) it wouldn't be incorrect to say the plane is flying on 3hp even if the engine is making over 4 1/4 HP at whatever rpm it is turning that prop.
 

Aviator168

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I dunno. The engine is adapted from a motorcycle where it is claimed to make 8hp at 4500 RPM. I don't think that engine is turning that direct drive prop on that airplane at anything close to 4500 RPM. Plus, if we correct for prop efficiency (maybe 70% at this low airspeed?) it wouldn't be incorrect to say the plane is flying on 3hp even if the engine is making over 4 1/4 HP at whatever rpm it is turning that prop.

The fact that it has a145 sq ft cantilever wing is impressive. It also tells that how little power it takes to maintain a level flight if you have a streamline body.
 

Tiger Tim

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I really like the EE Wren but surely that’s taxable horsepower, an old weird British calculation.
 

Chilton

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I think the 3HP rating as TT said is taxable horsepower rating, 8 HP actual is probably also correct. The Carden Ford conversion was 10 HP taxable, 32 BHP.
I think the recent excitement from Shuttleworth is that the Wren actually flew without the bungee launch assist and flew a circuit not a crow hop this year, the first time in many years.
If you want to know more about the EE Wren and much else of that era check out Richard Riding "the Early British Ultralights"
And for a pilots view Aeroplane Monthly carried an article last year by a new pilot describing his check out on it. I cant find the issue at the moment as we are moving flat so it is in a box somewhere!
 

cluttonfred

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I really like the EE Wren but surely that’s taxable horsepower, an old weird British calculation.

Like the French Citroën 2CV car…two “steam horsepower” from an old tax category. The original version actually had nine hp in the conventional sense and the last models after over 40 years of production had a whopping 29 hp.
 

cluttonfred

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Definitely needs to be a replica of the Wren offered as a homebuilt kit, for one of the 18-24HP paramotor engines. Laser cut wood, aluminum tube 'n' gusset, bicycle style carbon tube and wrap, whatever.

18-24 hp is enough for something a lot more practical than a Wren. DH Hummingbird? Gloster Gannet? Avro 558?

C079F7F9-430E-4844-930E-50DA61A99786.jpeg
2774A4C8-EB98-4AEB-B1FB-A41785DFBE93.jpeg
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Tiger Tim

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18-24 hp is enough for something a lot more practical than a Wren. Avro 558?

View attachment 125183
That Avro could be lovely in a little more modern wood construction (glue and gussets rather than a billion fiddly metal brackets) and a Kohler V-twin or something. Do we know anyone with experience designing small wood biplanes with 1920s flair? ;)
 
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