Item 1605
OTHER:
Helicopter - Outside - Coaxial - Cornu, Paul, 1907 - First flight
Cornu's Rotorcraft and Its Specifications Etc. For the consideration of lift with minimal power:
- History of the Helicopter ~ Jean Boulet (translated) Pages 21-24
- Cornu's Helicopter ~ First in Flight?
Article by Dr. Gordon Leishman in the 2001 Fall-Winter edition of of American Helicopter Society's publication Vertiflite.
- The two pages; Page 54 & Page 55. ~ Clicking on the pages will double their size. ~
- AHA:, 2007: Centennial of the Helicopter? From the AHS's Web site.
- Paul Cornu and His 1907 Helicopter: A postscript.
Article by Dr. Gordon Leishman in the 2007 Winter edition of of American Helicopter Society's publication Vertiflite.
- Not placed on Web; at least not by me.
Leishman uses Momentum theory to evaluate.
From Helicopter Theory page 30
2-1.2 Momentum Theory in Hover
Consider an actuator disk of area A and a total thrust T (Fig.2-1) It is assumed that the loading is distributed uniformly over the disk.
Pideal
= Tv = T√T/2ρA
Wing - Blade Aspect Ratio Comparison:
|
|
|
Speed: |
Aspect Ratio |
|
|
|
Sailplane: |
150 fps |
20:1 |
http://www.sailplanedirectory.com/zwf2.htm |
|
|
Spitfire: |
450 fps |
5.6:1 |
http://www.rdrop.com/users/hoofj/SpitIX.htm |
|
|
Cornu: |
At 218 RRPM the tip speed is 225 fps. Therefor at 0.8R(1) the speed will be 180 fps. |
4.2 (which includes the span of the large cutout) |
|
|
|
SynchroLite 3-blade: |
The tip speed is 550 fps. Therefor at 0.75R the speed will be 412 fps. |
22:1 |
|
(1) 0.8R instead of 0.75R because of the large cutout.
Wing loading, disk loading, blade loading,
The latter two are only applicable to the rudimentary Momentum Theory.
Calculations MT & BET from Access Database Program:
Specifications:
Rotor radius; = 3 M = 9.842 ft
Cutout: = 0.9 M = 0.3 R
Unsymmetrical airfoil selected. (8-H-12)
Twist: None
Taper: None
Chord = 2.34 ft.
Gross weight; 260 kg. = 575 lbs.
Airfoil: Cambered 8-H-12. The Cornu airfoil looks like a concave single skin airfoil as on a trike
Pitch = 9º
If the belts had not slipped, at 218 RRPM it should have flown, out of ground effect for 21 hp.
Momentum Theory, which is what Leishman used, shows 30 hp required. No tail rotor; 8-10% [Western], 10-12% [Kamov] = 10%. This would reduce the required power to 27 hp.
DESIGN: UniCopter ~ Rotor - Disk - Large Chord & Low Tip Speed leads me to believe that the wide chord (Rotor solidity 0.151) and large cutout has an advantage.
Comparisons:
See tables on these pages;
OTHER: ~ Aerodynamics - Rotor Disk - Dual Configurations
OTHER: Helicopter - Inside - Principal Assembly - Electrotor-Simplex (Ultralight & UAV)
- No tail rotor; 8-10%
[Western], 10-12% [Kamov] = 10%
DESIGN: UniCopter ~ Rotor - Disk - Large Chord & Low Tip Speed
Comparison Gyrobee to Cornu flying in ground effect.
- Gyrobee Gyrocopter, 500 lbs GW, 38-40 hp
- For the Cornu weight of 575 lb the power would have to be 575/500 * 39 = 45 hp.
- Mechanical vs. aerodynamic power transmission losses; (82% [Prop] * 82% [Rotor Figure of Merit]) - 5% [Mechanical ] = 72%. Therefore 72% of 45 hp = 32 hp
- In vs. out of Ground Effect; 15% - 20% [Leishman] = 17%. Therefore 32 Hp * .83 = 27 hp,
Thread on Rotary Wing Forum:
Engineering Analysis of the 1907 Cornu Helicopter
Thread on PPRuNe:
2007: Centennial of the Helicopter?
Bringing Conventional Momentum Theory and Blade Element Theory Closer To Cornu's Calculations:
Inverse Taper:
"... from whatever payload advantage resulted from its increased aerodynamic performance in hover and vertical climb. (Some preliminary studies indicate that perhaps inverse taper holds some promise in this regard.)"
~ by Prouty [RWP1 p.649] and Graviman (Mart)
Antoinette engine:
"The Antoinette engine was designed and built in France by Léon Levavasseur. Named after the designer's daughter, it was Europe's most widely used engine until 1909-1910. The first Antoinette engine dated from about 1901 and was used in a speedboat. By 1905, Levavasseur had produced a water-cooled engine with eight-cylinders arranged in a 90-degree "V" and with direct fuel injection. It was safe, strong, and fairly powerful, generating 50 horsepower (37 kilowatts) and weighing about 110 pounds (50 kilograms). Its power-to-weight ratio was not surpassed for 25 years."
Access Forms:
Test Conditions:
Helicopter Specifications:
Momentum Method:
Flight Hovering:
Additional Information on the Ability of the Cornu Helicopter to Hover in Ground Effect:
The Cornu Model: Leishman, in his latest article, has stated that "a model weighing up to 18 kg (40 lb) lifted by a 2 hp engine driving two contra-rotating rotors - was to make several sustained flights, in both hover and forward flight, and with many witnesses to the event." This is 20 lb/hp.
The Flettner 282 Intermeshing: "It was capable of lifting 16 lbs. per horsepower - a figure not attained to this day by any of the modern helicopters." ["this date" - unknown]
- The Flettner had a GW of 2202 lbs and a 160 hp engine.
- The 282 had an Intermeshing configuration and this configuration has a Thrust/Power efficiency that is meaningfully below the Side-by-side configuration.
- The twin Rotor Factor for my SynchroLites and UniCopters in the Access database is 1.39 +/-. This seems to be too close to the Coaxial's 1.41. However, for the fun of it 16 hp * 1.39 = 22.24 hp.
The Cornu Full size:
573.3 lb / 24 hp = 23.89 lb/hp Was this the GW weigh of his 13 November 1907 attempt when the craft was carrying a 121 lb sandbag?
Note Related to Coding of Prouty's Momentum and Blade Element in Hover:
The results of these calculations may give a 'required power values' that are too low.
This may be because the algorithms were meant for larger helicopters.
See;
OTHER: Helicopter - Outside - Single (1 seat) - Sikorsky VS-300
Introduction Page | SynchroLite Home Page | UniCopter Home Page | Nemesis Home Page
Last Revised: January 24, 2008
