Depoly/Release System

1. Field of the Invention

This invention relates to an apparatus for arresting uncontrollable motions in model aircraft by deploying a parachute to stabilize the aircraft, then jettisoning the parachute to resume normal flight.

2. Description of the Prior Art

The advantages of building and testing scale model aircraft are well known. Scale model tests provide data from which new designs can be verified, old designs can be improved and dangerous design defects can be discovered. In the course of testing, the models must often perform maneuvers where the risk of a crash are high. For example, in studying a particular design's ability to recover from a tailspin, the spinning motion may develop to a point where the operator cannot arrest the motion by manipulating the flight control surfaces. To avoid destruction of the model aircraft in these cases, it is necessary to provide the operator with a mechanism for regaining control of the aircraft.

While earlier developments include deploying a parachute to slow the aircraft and safely lower it to the ground, these earlier developments lacked the aspects of the present invention whereby the parachute can be jettisoned on command from the operator.

An application showing the use of a radio control system to deploy a parachute is described in U.S. Pat. No. 2,257,277 to Righter et al. However, the parachute described by Righter et al. remains attached to the aircraft and is used only to land the aircraft. The Righter et al. patent does not contemplate jettisoning the parachute. U.S. Pat. No. 3,497,168 to Finney et al. does teach jettisoning a parachute. In the Finney et al. teaching, a first parachute is deployed and after a predetermined interval the parachute is jettisoned. A second parachute is then deployed and the object safely lowered to the ground. Once the sequence described in the Finney et al. patent is initiated, however, the operator has no control over when the first parachute will be jettisoned. The present invention, on the other hand, gives the operator complete freedom as to when the parachute will be deployed and when it will be jettisoned without having to rely on a predetermined timing sequence.

Other prior art generally relating to the field of the invention includes U.S. Pat. No. 2,478,758 to Frieder et al., U.S. Pat. No. 3,45l,642 to Wieland et al. and U.S. Pat. No. 3,463,425 to Hibi, all of which use a parachute to safely lower a load to the ground. None of these patents contemplates jettisoning the deployed parachute.

It is therefore an object of the present invention to disclose an apparatus for arresting uncontrollable motions of a model aircraft.

A further object of the present invention is an apparatus whereby a parachute may be deployed and jettisoned at the command of the operator.

An additional object of the present invention is an apparatus performing the deploy and jettison operations on command using the same channel of a radio control transmitter.

These and other advantages of the invention will be readily apparent when considered in reference to the description and claims and taken in connection with the attached drawings to which they relate.

In the present invention a platform is rigidly affixed to the tail end of a model aircraft by means of a frame. The platform and frame may be manufactured from any suitable lightweight materials such as plywood for the platform and aluminum tubing for the frame.

The parachute which is deployed to stabilize an uncontrollable aircraft is stored on the platform during normal flight operations and is held firmly in place by an elastic band which is tightly stretched over the folded parachute. The elastic band is firmly attached to one side of the platform and has a metal loop fastened to the free end. The free end is stretched over the folded parachute and the metal loop is received between two eyelets which are rigidly fastened to the platform. A release pin is slidably positioned through the two eyelets and the metal loop and holds the elastic band over the parachute.

The shrouds of the parachute are connected to a riser having a closed loop at one end. A plunger is slidably positioned through the closed loop and holds the deployed parachute until the parachute is jettisoned. Since the parachute induces a substantial load on the plunger the plunger is held in place by a spring. A number of ways for operating the deploy and jettison mechanisms will suggest themselves to one skilled in the art. In the preferred embodiment, it is intended that a radio control device be used to deploy and then jettison the parachute; however, any other suitable structure such as altitude or spin-sensitive device may be used to operate the deploy and jettison mechanism.

The use of a radio control system comprising a transmitter, receiver and proportional digital servo of the type generally known in the art, gives the operator complete control over the timing of the deploy and jettison operations. The operator can deploy the parachute after trying other means of arresting the uncontrollable motions; for example, by manipulating the flight surfaces. Additionally, since the deploy and jettison operations are not dependent upon a predetermined timing sequence the operator has complete freedom to determine when the aircraft motions have been arrested sufficiently to jettison the parachute.

Another advantage of using a radio control device is that both the deploy and jettison operations can be commanded using a single control channel. Thus, the addition of the present invention to a research model has a minimal effect on the availability of control channels to control other operations.

It will be readily seen from the following detailed description that the invention will permit an operator to arrest uncontrollable motions of a model aircraft by deploying a parachute. Further, it will be seen that the parachute may then be jettisoned and that the sequence of both the deploy and the jettison operation are completely controlled by the operator.

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a side view of the present invention; and

FIG. 3 shows a schematic arrangement of aircraft mounted components of the present invention.

Referring now to the drawings, there is shown a preferred embodiment of the invention as it would be used to arrest uncontrollable tailspin motions. As best seen in FIG. 2, the apparatus comprises basically a frame 10, a platform 12, and a parachute 14.

Frame 10, in the preferred embodiment, is manufactured from aluminum but may be manufactured from any suitable material which is lightweight and has sufficient strength to resist the loads induced in the frame. Frame 10 comprises two tubes 16 each having a flattened portion 18 at one end which are rigidly attached to opposite sides of an elongated block 20. Although other techniques of securing tubes 16 to elongated block 20 will suggest themselves to one skilled in the art, in the preferred embodiment flattened portions 18 and elongated blocks 20 are fastened together by means of bolts 19. The other ends of tubes 16 are rigidly affixed in a conventional manner to the model aircraft 22. The tubes 16 may be shaped into any suitable configuration which will not interfere with normal operation of the flight surfaces.

Extending upward from flattened portions 18 are L-shaped brackets 24 to which platform 12 is fastened. In the preferred embodiment platform 12 is manufactured from a thin sheet of plywood but aluminum or any other suitable lightweight material may be used.

Parachute 14 is stored on platform 12 during normal flight operations and is held in place by an elastic band 26 having one end firmly fastened to the side of platform 12 while the free end is connected to a closed loop 28. The free end of elastic band 26 is stretched over stored parachute 14 and closed loop 28 is received between two eyelets 30 which are affixed to the side of platform 12. Elastic band 26 is held in this stretched position by a release pin 32 which is slidably positioned through eyelets 30 and closed loop 28. Release pin 32 is held in place by a resilient band 34 which is fastened at one end to release pin 32 and at the other to retaining clip 36 connected to frame 10.

Parachute 14 is stored on platform 12 during normal flight in a suitable folded position as is well known in the art. Parachute shrouds 36 are connected to a riser 40 having a closed loop 38 at one end which fits over a plunger 42. The plunger 42 in the preferred embodiment is manufactured from a bar of steel 0.0625 inch in diameter but other materials and dimensions may be used provided the loads induced in plunger 42 by parachute 14 can be safely accommodated. Plunger 42 and a rear support 39 is slidably positioned through a forward support 37 and one end thereof fits into a receptacle 43 in an upwardly extended portion 41 of elongated block 20. Plunger 42 is maintained in this position by a spring 44 having one end thereof attached to plunger 42 and the other end thereof attached to forward support 37.

The pin 32 is connected to a digital proportional servo 46 by means of a deploy cable 48 and in the same manner plunger 42 is connected to digital proportional servo 46 by means of a jettison cable 50. Deploy cable 48 and jettison cable 50, in the preferred embodiment, are standard 0.015 inch wire but any similarly thin gage material may be used. Digital proportional servo 46 is of any standard construction well known in the art.

In use, digital proportional servo 46 and associated power supply 54, receiver 52, and transmitter (not shown) are commanded to the armed position. Any standard radio control equipment of the kind widely known in the art may be used, but in the preferred embodiment Kraft Radio Control System's servo KP-12, receiver KPR-6, transmitter KPT-6, and power source KPB-500 are used. In the armed position, as shown in FIG. 3, deploy cable 48 which is connected to release pin 32 is slightly slack and jettison cable 50 which is connected to plunger 42 has sufficient slack to prevent jettisoning the parachute 14 when the servo is commanded to the deploy position. To deploy parachute 14 in the preferred embodiment the operator uses a transmitter of the kind widely known in the art to send a radio signal which is received on the model aircraft 22 by a standard receiver 52 also of the kind widely known in the art. Upon receipt of the deploy signal, digital proportional servo 46 rotates approximately 45.degree.. This rotation tightens deploy cable 48 which in turn pulls pin 32 from eyelets 30 and closed loop 28 releasing elastic band 26. This rotation also removes the slack from the jettison cable and readies the apparatus for the jettison operation. The parachute 14 is no longer restrained and the airstream pulls parachute 14 from platform 12 and inflates it. Due to the complex consideration of the airflows around a spinning research model 22, each installation of this invention should be reviewed individually to assure that frame 10 is shaped and located in a manner which will facilitate deployment of the parachute.

When the operator desires to jettison parachute 14 he simply commands servo 46 to the jettison position which tightens jettison cable 50 causing plunger 42 to retract. As plunger 42 is pulled from receptacle 43 of upwardly extended portion of elongated block 41, closed loop 38 is pulled free by the drag load on parachute 14 and parachute 14 is thereby jettisoned.

It will be understood that the foregoing description is of the preferred embodiment of the invention and is therefore merely representative. Obviously, there are many variations and modifications of the present invention in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.