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And now after a long time behind the calculations, now at last we can begin to build our Mark 3


It will not be easy, let alone fast so arm yourself with patience !! 🙂

Now that we have all the data, we have to transfer them to a support that will be the "mold" for the envelope so that we will not achieve them one by one.

The ideal support must be sufficiently rigid so as not to be damaged by use and do not twist when we draw the shape.

I chose a corrugated plastic holder, but that's fine cardboard or other.

mother gore plan

Once done, we have to cut out the design obtained in order to separate the two half-gores of its holder and in this way they can be used to cut out the gores that will make up the balloon.

mother gore

Now that we got our "mother gores" we will use them to make all other segments that will make up the balloon.

For this project the gores (15 upper semi-gores and 15 lower, which then will join) that we do are 15, but if you have decided to design it you varying sizes, you will use the number of gores you decided (Sp).

To make the hot-air balloon gores , we can use the cellophane commonly used to whiten (possibly the thinnest you can find) or tissue paper.

We start to overlap more sheets (I will use the cellophane but you choose what you prefer). I've got stacked 4 at one time.

Then leaning over the mother half-gore, stop it with the weights to make sure it does not move, and with a permanent marker trace the contours.

Warning: The solvent in the marker can damage the cellophane in doubt do a test or change marker!!

When you have drawn the outlines, carefully remove the weights and the mother gore and helping again with weights, with a ruler and a utility knife, carefully cut out the contours.

Repeat this for as many times as necessary to get the semi-gores you need, as said before, in our case will be 15.

When you've got all the upper and lower semi-gores we're going to join them, taking care to match the edges.

I recommend using the adhesive tape -if possible- for high temperature

To join it proceed first to combine each upper gore with its lower half.

Once done we should have 15 complete gores.

Now we have to put them together, gluing them side by side. I advise you to get help from someone because it is not easy and you are likely to do a bad job done.

Another tip, you can use an ironing board, so that it is easier to bring the edges to be bonded.

Pay close attention to the corners, because if they are not adequately reinforced will be the first to break.

To strengthen them, once you get them together with adhesive tape, re-pass them making the X with the same.

If you did everything correctly, after merging all segments, you will need to combine the last with the first, so going to close the envelope.

Remember to also reinforce the envelope apex is the point subjected to greater effort.

To do this, instead of the normal tape you can use a reinforced tape that can be purchased at any hardware store.

Did this your envelope will be complete and then we will proceed to the construction of the burner.

First, with the sturdy wire of 1 mm in diameter do a circle of diameter equal to Db, then in our case it will be 60 cm.

Now we will have to choose what kind of fuel use.

This type of balloon that we are planning together is capable of carrying a payload of approximately 2 kg which obviously we will put all in fuel, We can then choose whether to buy / self-build a torch of rags soaking with wax, or whether to build a rudimentary gas burner buying and modifying a torch of those with the gas can.


When you have decided what to use, you'll have to fix it to the ring previously constructed, so that it is stable and not fluctuate on all sides.

To fulfill this purpose I used -as in the Mark I & II some steel strands, obtained pulping the common thread of bicycle brakes.

thin steel cable

Now that we have built the burner, we will use again the reinforced tape to attach it to the mouth of the balloon.

We have now finally finished to build our balloon !!!

Like the others, to make it take off we have to choose possibly a cold morning so that the air is very calm (help with the weather forecast, the best situation to fly is without wind).

Inform yourself before launch about regional / state regulations of your country (here in Italy's ENAC)

I strongly suggest -especially for this model-, ask for help at least 2 persons cause the envelope will be bulky and difficult to manage, if you are alone, during the pre-launch maneuvers.

Started, while a your collaborator holds high the apex, to fill it with air (at the beginning not need to be hot) with hair dryer or a fan.

Once the swelling starts to take the shape that will have, blow hot air inside, or with the hair dryer or with a torch in the canister.

When it swells, and vertically, turn on the burner and in the meantime continue to warm.

Within a few minutes will take off, leaving everyone present excited and speechless!!! 😀