06 Envelope
Back to overview: Tutorial i4
It does not matter if you have a transparent or silver envelope. You can handle both the same way. Before you fill them with lifting gas, test them once with air, to train everything. Once you use helium it´s one stepp trickier since the balloon likes to fly away all the time. You can use a hairdryer (cold!!) to fill the envelope. The envelope is full once most of the wrinkels have disappeared and it is nicely taut. Be aware, the transparent envelopes are a bit more flexible, so have less wrinkels at the seams compared to the silver ones.
To seal the envelope, use one of the clips, like shown in the picture. Fold the tube vent several times, to make sure no lifting gas will leak. You can use your wet lips to check if lifting gas is leaking, it will feel cold.
Set up your silent_runner as shown in the pictures. To connect the parts to the envelope you use TESA sticky tape. Fold one end of each tape, to later remove it easily. If you remove the sticky tape, do it with some care, to not rip the envelope. You can freely move the motor gondula and battery to front and back, depending on the position of your payload, to level the airship. Use some little ballast thins (coins, lead, etc.) to fine tune the balance of your airship. If the airship is filled with lifting gas, make sure your balance it a little heavy (1-2 gram). This way it will come down on it´s own if something goes wrong.
Make sure you are prepared to answer a lot of question to all people around, since now you are one of the very few people in the world who have a flying racing airship. Be prepared, now the flying starts: 07 Flight
Pro Tip1: To get the air/helium out of the balloon, use some tube and connect a vacuum cleaner. This can also be done before inflating with helium, to suck theremaining air out of the envelope.
Pro Tip2: If you like to have a balloon without wrinkels, you can use your hairdryer (hot air) to carefully heat the inflated envelope in the regions were the wrinkels are. This slightly stretches the material and most of the wrinkels dissappear. This works better for transparent than for silver envelopes.
Caution! If you heat too much the envelope can melt!
Pro Tip3: If you will fly your silent_runner in difficult areas and you expect some hard crashes, it is a good idea to put a bit of strong tape to the envelope, where the motor gondola is placed. If the ship hits the ground really hard, it can happen that the propeller cuts the envelope, which can be prevented by some strong tape in the area of the gondola. (Pro Tip from Arne)
