Here's what I have taken from AAF Manual 55-0-1, June 1945:
1) Type Q-1 Electrically Heated Casualty Blanket, Stock No., 8300-037670 (Class 13) is designed to maintain the bodily warmth of wounded personnel aboard bombardment type aircraft. It operates on the 24-volt airplane electrical system. Proper heat balance is maintained so that a man, adequately clothed for a bombing mission, is kept comfortable for a period of three hours at any temperature ranging from -40°F to +40°F. Furnished with the blanket is an extension cord and an automatic ambient control box to regulate the power output and maintain an even heat in the blanket. The box is designed to be attached to the Q-1A rheostat. The extension cord leads from the pigtail on the blanket to the female plug on the control box. The male plug is inserted in the left receptacle for the rheostat. By turning the rheostat to high, the blanket and control box are placed in operation.
The blanket should always be operated through the control box, but, if necessary, it may be connected directly to the Q-1A rheostat and the heat controlled manually by means of the rheostat. In such a case care must be taken not to let the patient get uncomfortably hot or burn.
2) The blanket is laid out on the floor of the aircraft and the patient placed in the center. Do not remove clothing. The patient should be wrapped well, insuring that all parts of his body are covered with the blanket and that all flaps are properly folded to eliminate openings. All tie straps should be secured. A head rest of jackets or clothing not in use should be fashioned to make the man more comfortable. In the earlier models of bombardment aircraft, in which the oxygen hose extension is of insufficient length, a four-foot extension oxygen hose (AN-T-23A) should be procured with proper fittings.
3) When stowing the blanket, it is essential to place it where it will not receive abuse which might impair the electrical circuits. One should fold the head, foot and side flaps onto the center section and place the extension cord on the foot section; then roll as tightly as possible from the head to the center and from the foot to the center; finally tying with the two blanket tie straps furnished. The whole blanket should never be washed or dry cleaned, and should always be thoroughly dried before it is rolled up. If the blanket becomes stained with blood, the rubberized liner may be cleaned with soap and warm water. Care should be taken, however, to prevent the entire blanket from being immersed in water. This may cause the internal pile lining to become damp and short the circuit. Repair of tears, snags and rips in the fabric should be handled in the same way as normal fabric repairs. However, under no circumstances should the blanket be sewn completely through the three layers of fabric. All other repairs of an electrical nature should be made in accordance with standard practice and by the proper agency.
4) The Casualty Blanket should be inspected visually at regular intervals and its electrical system checked regularly. Broken wires, or poor or defective connections will affect the resistance through the circuit and materially decrease the operating efficiency of the blanket. To check the wattage on the circuit, the simplest method is to run the rated voltage of 27 through the power lead into the blanket, placing an ammeter in series on the heating circuit. The reading should be 9.2 ± .7 amperes and a corresponding wattage of 250 ± 17.
I hope that the above will be of some use to you, and should you need an illustration of same, kindly let me know.