US1387514A - Lift-indicator eor elying-machines - Google Patents

Description

A. s. REYNOLDS.

LIFT INDICATOR FOR FLYING MACHINES.

APPLICATION nun mm. 14. 1912.

1,387,5 1 4. ted Aug 16, 1921.

2 SHEETS-SHEET I.

Inventor A. s. REYNOLDS.

LIFT- INDICATOR FOR FLYING MACHINES.

APPLICATION FILED MAR. 14. I911.

1 ,5 1 4;, Patented Aug. 16, 1921.

, P- 2 SHEETS-SHEET 2- Q 1 x2, W

Inventor Atlor ya.

ANITA S. REYNOLDS, OF GREENWICH, CONNECTICUT.

LIFT-INDICATOR FOR FLYIN G-IVLACHIN ES.

Specification of Letters Patent.

Patented Aug. 16', 1921.

Application filed March 14, 1917. Serial No. 154,853.

To all whom it may concern Be it known that I, ANITA S. REYNOLDS, a citizen of the United States, and a resident of the town of Greenwich, county of Fairfield, and State of Connecticut, haveinvented a certain new and useful Lift-Indicator for Flying-Machines, of which the following is a specification.

My invention relates to flying machines of the heavier-than-air type in which the weight is sustained in the air by the reactions resulting when one or more aerofoils are moved through the air edgewise at a suitable angle of incidence. This movement through the air causes a total reaction on the aerofoils resultin in both positive and negative pressures being exerted on the lower and upper faces respectively. Posltive pressure being a compressive action on the under face of the aerofoil and negative pressure being a partial vacuum over the upper face. It is the resultant upward components of these reactions on the aerofoils which cause the machine to be sustained in the air. The magnitude of this sustaining force is dependent on two general conditions, 11. e. the angle of incidence of the aerofoils and the speed of the device.

The object of my invention is to provide means whereby an aviator will be informed as to the sustaining force acting on the aerofoils at all times during flight and that such sustaining force is not dropping below a certain minimum value known as the stalling point, that is, that value at which the machine will fail to be sustained in the air.

A further object is to inform the aviator that certain maximum values are not exceeded when suddenly righting the machine in vol laning or diving.

A urther object is to keep the aviator advised that he is operating the machine at such an angle as to secure the most efficient pressure on the aerofoils.

A still further object is to produce a device which will be simple and cheap in construction, effective in operation and not likely to get out of order.

These and further objects will more fully appear in the following specification and accompanying drawings considered'together or separately.

I have illustrated one embodiment of my invention in the accompanying drawings in which like parts in all of the several figures are indicated by similar reference characters and in which,

F gure 1 is a side elevation, partly in sectlon, of my invention, the same being shown 1n connection with a visual indicator.

F g. 2 s a bottom plan view of the device.

F g. 3 1s a sectional view of a modification.

Ijlg. 4 1s a side elevation of a portion of a b1plane embodying my invention, and

Fig. 5 1s a diagrammatic view of the devlce for automatically stabilizing an airplane.

In carrying out my invention I employ a flexible diaphragm 1, preferably corrugated, which is carried on an annular frame 2 and secured by its edge to the annulus by means of a ring 3 which is fastened to the frame by means of screws 4 which pass through the edge of the diaphragm.

The frame 2 is secured in an aerofoil in such a manner that the upper face of the diaphragm is exposed to air currents on top of the aerofoil while its lower face is exposed to air currents on the bottom of the aerofoil.

A bracket 5 is carried by the ring 3. Pivoted to lugs 6 on the bracket is a bell crank lever '7. One arm of the bell crank is pivoted to a post 8 which is rigidly secured to the center of the diaphragm 1. The other arm of the bell crank 7 carries a pin 9 which en gages a slot in a lever 10 pivoted in lugs 11 on the bracket. Carried on the pivot of the lever 10 and insulated therefrom is,a contact finger 12.

The end of the bell crank lever 7 which engages the post 8 is normally held in contact with an adjusting screw 13 which is carried by an arm 14 projecting from the bracket 5. A look nut 15 is provided for securing the screw 13 in position. A spring 16 is secured to the bell crank 7 at one end while its opposite end is attached to a tensioning screw 17. The screw 17 is mounted in the bracket 5 and is provided with a lock nut 18. g

The free end of the finger is adapted to engage anyone of a series of contacts 19 carried 011 a standard projecting from the lower face of the ring One pole of a source of current 20 is at tached to the finger 12 and each of the contacts 19 is connected to an incandescent lamp 21 carried in the fuselage of the machine at a point within the vision of the aviator.

The other side of each lamp is connected to a common return wire 22, in which is a switch 23, to the source of current.

Instead of the lamps 21 any other form of indicator may be employed.

In Fig. 3 I show two diaphragms 1 on or near the top surface of the aerofoil and 1 on or near the lower surface thereof. The diaphragms are connected by a strut 2a the center of which is engaged by one arm of a bell crank 7 the other arm of' which engages and operates a contact finger which functions in the same manneras does the. finger 12 in Figs. 1 and 2. By this construction airpockets 011 one side or the other of a single diaphragm will be avoided. A perforation 25 in the upper diaphragm 1 will serve to prevent a difference in altitude or temperature from changing the relative positions of the diaphragms.

In multiplane machines it may be desirable to place one or more instruments in each aerofoil and in Fig. 4 I have shown a biplane with an instrument in each wing. It will be.understoo'd that more than one instrument in each wing may be employed if necessary or desirable.

As the angle of incidence depends upon the speed and weight of the machine it is obvious that at a given speed the lighter the machine the flatter, or more nearly the horizontal the angle of incidence, is, and the most efiicient pressure will be different from that of a heavier machine. During flight as the machine becomes lighter by reason of fuel consumption or from any other reason the angle of incidence may be flattened and the minimum sustaining force will be lowered.

In Fig. 4 is shown means for indicating variations in the lift of the machine due to the consumption of fuel. A fuel tank 26 is shown in dotted ilines. This tank may be located at any desired point and is illustrated as being withinthe fuselage 2?. The tank is provided with a float 28 which is coupled to a pointer 29 which will indicate on the row of lamps or other indicating device the position in which the diaphragm 1 I should be when the most eiiicient operating condition of the airplane is reached as the load varies.

In Fig. 5 I have shown an arrangement in which the indicating device may be employed for automatically stabilizing for pitchin In the figure is shown, diagrammatically, a: diaphragm 1, as before and a calibrated bell crank 30. reversible motor 31 is mounted on trunnions 32 within the fuselage 27 and said motor has secured thereto an arm 33 which ezitends over a counter'shaftfi on which are mounted the control levers. A pulley 35 on the countershaft is connected by cables with a tail flap or elevator 36. The arm 33' passes over the countershaft and is curved on a radius struck from the center of the shaft. A

lever 37 is pivoted on the shaft and is provided with a sliding rod 38 which is normally pressed downward by a spring A crank 40 is pivoted on the lever and one arm thereof engages the upper end of the rod. A hook 41:1 carried by the lower end of the rod 38 engages the under side of the curved portion of the arm 82 Carried on the countershaft is a worm wheel segment which is engaged by a worm as on the metor shaft.

The motor 31 is connected through a reversing box 1a with lead wires 15 which connect with contacts 16 adapted to be engaged by a central contact 4-7 as the bell crank 30 is moved up or down by the air pressure. A source of current L8 is connected in series with the reversing box 4A and with the central contact I? by means of a lead wire 19.

The operation of the device shown in Figs. 1, 2, 3 and 4 is as follows lVhen the airplane is at rest the air pressure on opposite sides of the diaphragm 1 will be equal and it will therefore assume a central position. As the airplane is set in motion and gradually gains speed the air pressure on the bottom of the aerofoil will increase and decrease on the upper face thereof. This will cause a consequent move ment of the diaphragm upward and by properly calibrating the spring 16 the device may be made to weigh the force tending to maintain the airplane in the air at all times.

. If with a given speed of the machine the indicator shows that the pressure is not sufficient to support it at the angle of incidence at which it is flying, the operator will swing the tail flap upward. This will increase the angle of incidence above the horizontal until the indicator denotes that there is sutlicient pressure under the aerofoil to support the machine. The tail plane will now be lowered until the craft flies on an even keel but with the increased angle of incidence.

In volplaning, when it is desired to right the machine the aviator by observing the in dicator will be able to see that certain maximum values are not exceeded and that the machine is not strained beyond its safe mechanical limits.

In the form of the device shown in Fig. 5 when the pressure on the underside of the diaphragm decreases the center contact 17 will engage the contact 46 and the motor will operate to raise the tail flap and point the machine upward. When the pressure on the bottom of the diaphragm increases the contact 17 will engage the contact 16, the motor will be reversed and the tail flap will be lowered.

When it is desired to disconnect the automatic stabilizing device the'crank arm 40 is moved toward the lever 87. This will raise the hook 41 and with it the arm 33 to tilt the motor on the trunnions and disengage the worm from the worm wheel segment. The machine may now be manually stabilized by the usual means.

The position of the diaphragm in the aerofoil may vary in different types of machines but it preferably is so situated that it is free from the direct influences of the propeller orpropellers and near the center of support of the airplane.

In accordance with the provisions of the patent statutes I have described the principle of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is merely illustrative, and that the invention may be carried out in other ways.

Having thus described my invention what I now claim as new and desire to secure by Letters Patent, is:

1. An airplane comprising a supporting surface, propellin means, a receptacle adapted to carry el, a diaphragm in the supporting surface, an indicator actuated by the diaphragm for denoting the value of the lift on the supporting surface, and means actuated by variations in the load as the fuel is consumed forindicating the minimum value of the lift necessary to sustain the airplane in the air.

2. 'An airplane comprising a plurality of supporting surfaces, propelllng means, a receptacle adapted to carry fuel, a diaphragm in each supporting surface, an indicator actuated by the diaphragm for denoting the value of the lift of the supporting surfaces, and means actuated by variations in the load as the fuel is consumed for indicating the minimum value of the lift necessary to sustain the airplane in the air.

3. A device of the character described comprising an aerofoil, a diaphragm in the top camber, an axially alined diaphragm in the bottom camber, said diaphragms being connected together at their centers, a lever engaging the connection, and means actuated by the lever for indicating the air reactions above and below the aerofoil.

4. An aerofoil, a diaphragm in the top camber thereof, a diaphragm in the bottom camber, a connection between the diaphragms, whereby said diaphragms may be deflected in unison by differences in air pressure above and below said aerofoil, means for counterbalancing the deflection, and means for indicating and recording the defiections of the diaphragms, said diaphragms being so situated relatively to the top and bottom cambers as to offer a minimum resistance to the passage of the aerofoil through the air.

This specification signed and witnessed this 12th day of March, 1917.

ANITA S. REYNOLDS.

Witnesses:

NIEL MORROW LODD, ETHEL H. TILSON.

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