1. Title of the invention
Rain Water Tightness Test Box for fighter and trainer aircrafts.
2. Field of invention
It is a mechanical engineering design used for Rain Water tightness testing and to find the life of the Rubber Gasket/P-rubber used in the Assembly, replicating the same conditions outside the built aircraft. The situation will be simulated with the design as per all the requirements on the Aircraft.
3. Use of invention
This invented Rain Water Tightness Test Box finds its applicability in Fighter and Trainer aircrafts for the study of rainwater tightness in the water tightness areas. This Rain Water tightness test box can also be used to find life of the rubber gasket/P-rubber used on the assemblies at the rain water tight areas of the aircraft.
4. Prior art
Rain water tightness testing is done on the aircraft to check for the rain water entry to the water tight zones of the aircraft as per the standards ADS-36.2
For the Inspection, Maintenance and Replacement of the LRUs and other Systems, either daily or periodically, cutouts and openings are given in the fuselage of the Aircraft. These cutouts are covered by Hinged door or Removable Cover using Quick Release Fasteners depending upon the mode of inspection. To Prevent the Rain water entry Rubber Gaskets/P-rubber, Sealants and water Drain path/holes are provided on the Door and cover assemblies.
5. Draw backs of prior art
1) Rain Water tightness Testing is done on the completely built Aircraft with Door and Cover Assembly and Cannot be carried out until the aircraft is built completely.
2) If any water traces are found after the Testing due to damaged rubber gaskets/P-rubber or faulty application of sealants or fasteners wear out, the rework has to be done on the built aircraft which halts/delays the other works to be carried out at these areas of the Aircraft.
3) As rework is done on the built Aircraft, there might be chances of damaging the adjoining structures and the scope of a neat and improved rework is limited.
4) Rework might require new parts to be fabricated or replace the existing faulty parts which in turn will delay the next rain water testing schedule and in turn delay the completion of the aircraft.
5) Addition of new parts will lead to adding of the weight and is not cost effective too.
6) As the door and cover are removed periodically and installed, it is difficult to find out when the rubber gasket/P-rubber get worn out until specific test it done. This in turn doesn't give the duration or the number of cycles after which the gasket/ fasteners have to be replaced.

6. Comparison between prior art and present invention
This invented Rain Water tightness test Box ensures that the design to be complied for the rain
water tightness on the aircraft is tested and is acceptable to be assembled on the aircraft.
Using this Rain water tightness test box, the design of the door/cover assemblies can be improved
upon until the water tightness is achieved, one can find out whether the Rubber gasket or P-rubber
works better for the water tightness and also the appropriate positioning of water drain holes or
path can also be decided. Once the design is found satisfactory and meets all the Standard
requirements according to ADS-36.2, it can be installed on aircraft.
This Rain water tightness test box enables the test to be carried out separately without waiting for
the aircraft to be built completely.
This invention also helps to know the number of cycles of opening and closing of door/cover after
which the rubber gaskets/P-rubber needs to be replaced.
7. Aim of the invention
Aim of the invention is to eliminate the draw backs of the present practices and ensure that the design developed for water tight areas of the aircraft are fully water tight and comply to the requirements of ADS-36.2.
8. Summary of the invention
The door and cover assembly parts and the required structure parts are fabricated according to the drawing requirements. Test box parts area also fabricated according to the drawing specifications and requirements. Was decided to use P-rubber instead of Rubber Gasket in this study. Detail design was carried out with P-rubber in the Door/Cover assembly.
This Rain Water Tightness Test Box can be used at two stages.
Stage-l:-To test the design of door and cover assembly for the water tightness:-
a) The Door/cover assembly parts are assembled as per the door/cover assembly requirements. It is then assembled with the rain water tightness test box with all the sealing requirements as per the test box assembly requirements.
b) Water is then filled on to the water collection Tray provided on the test box. Water is allowed to remain still for 2 hours.
c) After 2 hours the water is drained out and the box is checked for any trace of water inside it. If no water is found then the design is found to be good for the water tightness and is implemented on the aircraft.
d) If water entry is found then the required design changes are made and the steps 'a'.'b'and 'c' are repeated until the water tightness result is obtained.
Stage-2:-To test the life of the P-Rubber/Rubber gasket :-
a) Once the water tightness result is achieved, the box can be used to check the number of cycles 'N' of ooenine and closing of door/cover the P-rubber/Rubber gasket sustains.

b) The door/cover is operated upon daily for 'N' number of times for a period of a week in the open atmosphere in real time. The box is then tested for the water tightness as in Staee-l.lf no water is found then the P-rubber/Rubber gasket seems fine and there is no wear out of it.
c) Steps 'a' and 'b' are repeated at more frequent intervals until the water tightness test fails and some traces of water is found in the box. Inspection is then carried out to check the condition of the P-rubber/Rubber Gasket and the intensity of wear out is noted before replacing it with a with a new one.
d) This 'N' number of cycles at which P-rubber/Rubber gasket wears out gives the life of the P-
rubber/Rubber gasket on the aircraft.
e) In the assembly drawing a note for the compulsory replacement of the Rubber gasket after the' N'
number of cycles can be given after which the gasket has to be replaced for effective water tightness.
9. Brief description of drawings
Fig. Sheet-1 shows the view of the Prior design of DFCC hinged door Assembly on completely built Aircraft, on which the rain water test is conducted
Fig.Sheet-2 shows Prior design of Radome Cover Assembly on completely built Aircraft, on which the rain water test is conducted.
Fig.Sheet-3 Shows the the view of the Present design of DFCC hinged door Assembly on Present Invention Rain water tightness test box, using which the rain water test is conducted .
Fig.Sheet-4. Shows the the view of the Present design of Radome Cover Assembly on Present Invention Rain water tightness test box, using which the rain water test is conducted.
10. Statement of invention
This invented Rain water tightness Test Box enables us to design the Door/Cover Assembly to Fulfill the Requirements of the Water tightness standard ADS-36.2. By this rain water tightness test box all the results which can be obtained by rain water test on a built aircraft, can be obtained without waiting for the aircraft to be built completely. Any design changes can be done and test carried out again within a short period unlike on a built aircraft which takes up more duration.
11. Detailed description of invention
The Rain water tightness Test Box consists of :-
(1) Box made of either Metal or Composite.
(2) Tray Box
(3) The Door or the Cover assembly which has to be tested for water tightness.
(4) The surrounding structure parts to which the door/cover assembly is assembled as per on the built aircraft
The Tray Box and the Box can be assembled together with a structural member either using bolt & nut or bolt & anchor nut arrangement. Then the door/cover assembly is assembled to the Rain Water Test Box according to the aircraft assembly requirements. Rain water test is later conducted.

Claims
1. The Rain water tightness testing can be simulated separately without waiting for the aircraft to be built completely.
2. The improvements in design and retesting can be carried out outside the aircraft without disturbing the other operations on the aircraft.
3. This test box predicts the 'N' number of cycles after which the rubber gasket/P-rubber has to be replaced to achieve a positive water tightness on the aircraft.
4. By this invention the wear and tear of the parts on the aircraft can be eliminated as the test is carried out and the design for the rain water tightness is finalised.
5. This is cost effective as the new parts to prevent the rain water entry and rework on the aircraft are avoided.
6. The increase in weight due to addition of new parts can also be eliminated.
7. This test box eliminates the delay of other aircraft operations which may arise due to the rework given to prevent the rain water entry on the completely built aircraft.
8. Time taken for the subsequent rain water tightness testing is considerably reduced.