1.  Design and Fabrication of airship envelope for indoor remote controlled airship

The task assigned was to design and fabricate the envelope of a small indoor airship to be operated by remote control. Problem definition demanded a small (not exceeding 2 m diameter) airship that would fly at around 1 to 1.5 m/s operating at an altitude of about 10 m. The scope of this project included  selecting the best possible design for the indoor airship, designing the envelope for the airship fabrication of the envelope, and documentation of the problems faced and lessons learnt.
For the indoor airship, the lenticular profile of the envelope was selected. This has several inherent advantages over the conventional airship considering indoor flight. Maneuverability in all directions was one of them, especially when combined with a thrust vectoring system with differential thrust control.
Material selection for the envelope was both limited as well as disheartening. A market search was done for possible choices of materials. Very few materials were found. Those that were found, were inherently heavy and this inturn necessitated the increase of the dimensions of the airship. Adhering to the space and volume constraints given in the problem, as well as maintaing the lenticular profile of the hull proved to be a challenge in itself. Further analysis was done, and the final dimensions were decided upon.
Fabrication of the hull was done at a Jogeshwari toy manufacturer who had the required High Frequency welding machines. The airship hull was manufactured successfully. There were no leakages or pinholes present.
After further inspection of the hull, and a trial inflation with air, the envelope was inflated with Hydrogen. Lift obtained was more than theoretically calculated. This made the project a partial success. Further work needs to be done in maintaining the shape of the hull after inflation.

You can contact Mr. Rahul Sangole here.

This project discusses possible use of electric motors as a propulsion system for a remotely controlled airship and gives technical evaluation of various electrical DC brushed motors on the basis of an extensive net search, market search. It also includes Design, Fabrication and Testing of a test rig for measurement of Thrust of propulsion system. Further it consists of procurement of a control system for controlling direction and speed of electric motors and operating it on the same. The propulsion system consisting of electric motors giving desired thrust has been successfully used to drive a Lenticular airship. The propulsion system with electric motors and a thrust measurement rig are prepared according to the requirement and within prescribed duration. The added advantage is that the project was completed with lesser expenditure as compared to the estimated cost. The conclusion is that the DC electric motors available in the market can be used successfully for a remote controlled airship. The thrust with propeller mounted can be estimated by using the thrust measurement rig. The author is now working on the speed and direction control circuit for the DC motors.

You can contact Ms. Kshitija Deshpande here.

Project Summary

One of the perennial problems of the airships has been their lack of control power, especially at low speeds In order to alleviate this shortcoming, airship control by thrust vectoring was considered. Given below are the main advantages of thrust vectoring.
Vertical / Short Takeoff:The thrust of the airship can be directed up by 90 degrees. This enables the airship to have vertical takeoff or short take off. The optimum angle of thrust vectoring from the horizontal would be determined from exhaustive flight tests.
Vertical / Short Landing: The thrust of the airship can be directed down by 90 degrees. This enables the airship to have vertical / short landing. This enables to land the airship in smaller area than would be possible with fixed thrust line and with a greater range of static heaviness.
Maximum weight available for gondola was taken from Mr. Rahul Sangole while Ms. Kshitija Deshpande gave the available thrust of different motors and the required thrust. Suitable motor was selected along with mobile phone battery as the power supply. Different mechanisms were conceived and the final one was selected on the basis of their advantages and disadvantages. A market search was done to find servo motors which were light but having maximum torque. A 4 channel fm transmitter and receiver kit was obtained along with servos. Also suitable plastic gears were explored having ratio of 1:3. A prototype of gondola was made using thermocole to test the mechanism. On its success, the final gondola was made using balsa wood, plastic jar and a pair of steel rods. The mechanism was tested before fitting it to the envelope. After inflating the envelope with hydrogen, testing was carried out of the airship. It was found that the thrust vectoring gave an airship more maneuverability. Future developments to be carried out include use of thrust bearings to reduce the friction and use of a better gondola attaching system to the envelope.

You can contact Mr. Rohit Belapurkar here.
 

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