With Air Swimmers swarming all over the gadget scene and as a tribute to the original Air Swimmers, I wanted to see just how easy it is to build one myself.
Air Swimmers come cheap, but they are quite large compared to modern RC blimp standards, making them not very manoeuvrable in smaller rooms. So with Plantraco creating a new class of nano blimps I wanted to check how difficult it is to build an air swimmer in the nano blimp class, i.e. based on a 9" latex balloon.
Building a working Nano Air Swimmer proved to be quite simple (keeping it simple being the key). It's all in the tail: everything is done with just one servo. The servo combines propulsion and steering, as in commercial air swimmers.
While commercial air swimmers move their center of gravity back and forth to move up and down, I went for an even further simplification: the nano air swimmer is permanently pointing slightly up and moving forwards means moving up, stopping means moving down (a trick used in 2ch toy blimps).
Check out how it performs in this video:
Note Februari 27th 2012: I corrected a large number of text errors, but there are probably quite a few still. English is not my native language. Please feel free to point out any mistakes.
Air Swimmers come cheap, but they are quite large compared to modern RC blimp standards, making them not very manoeuvrable in smaller rooms. So with Plantraco creating a new class of nano blimps I wanted to check how difficult it is to build an air swimmer in the nano blimp class, i.e. based on a 9" latex balloon.
Building a working Nano Air Swimmer proved to be quite simple (keeping it simple being the key). It's all in the tail: everything is done with just one servo. The servo combines propulsion and steering, as in commercial air swimmers.
While commercial air swimmers move their center of gravity back and forth to move up and down, I went for an even further simplification: the nano air swimmer is permanently pointing slightly up and moving forwards means moving up, stopping means moving down (a trick used in 2ch toy blimps).
Check out how it performs in this video:
Note Februari 27th 2012: I corrected a large number of text errors, but there are probably quite a few still. English is not my native language. Please feel free to point out any mistakes.
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Signing UpStep 1: Materials and Tools
Plantraco does not explicitly comment just how small and light their Nanoblimp is. From the "helium + balloon sets" they sell with it, I gather it uses 9" balloons and has a gondola around 6g or less. 6g is the "guaranteed" lift capacity of a fresh 9" latex balloon. So my goal was to keep everything attached to the balloon under 6g.
Used RC gear:
For the tail:
You can get all of te above at aether-sciences.
For assembly and trimming:
All this is added to a 9" latex balloon, inflated with helium (and treated with Hi-Float). You can get it at the balloon shop (1-2 EUR for one) or bring home a helium bottle (rented or bought, around 50 EUR for a canister + 50 balloons). Depending on temperature and moisture a latex balloon will last longer or shorter. The spare buoyancy needed for the nano air swimmer lasts roughly a day.
Tools:
Used RC gear:
- An ultra micro receiver under 1g. I used my favourite 0.65g DelTang Rx33 DSM2 receiver. This is the most expensive part at around 30 EUR. With a slightly larger 11" balloon you can use the 2.2g OrangeRx R415 which can be found at 22 EUR to 10 USD, depending on the supplier.
- An ultra micro servo under 2g (a regular type, not a linear one). I used a so called 1.7 g servo, which actually weighs 1.9g with wires and connector. Make sure the connector is compatible with your receiver. Such a servo goes 12 EUR to 4 USD, depending on the supplier).
- A 1s LiPo battery around 2g. I used a Zippy 50mAh cell. With a fresh 9" balloon (carrying 8 g) or an 11" balloon I was also able to use a more common 2.5g 80mAh one. Such batteries should cost around 5 EUR or less. Obviously you will need a suitable charger (not shown).
- A 25cm battery extension lead to connect your battery to the receiver. A shorter lead works too, but it allows for less trimming the weight distribution. Specialist suppliers of micro RC gear can make that to order for under 4 EUR.
For the tail:
- Some EPP sheet (Expanded PolyPropylene), 3 mm thick. I used a triangle with two 16 cm long rectangular sides
- About 5cm of 0.8 to 1mm diameter carbon rod.
You can get all of te above at aether-sciences.
For assembly and trimming:
- Some sewing thread.
- Superglue.
- Tape (scotch tape or selotape).
- A couple of grams of putty, to be used as trim ballast.
All this is added to a 9" latex balloon, inflated with helium (and treated with Hi-Float). You can get it at the balloon shop (1-2 EUR for one) or bring home a helium bottle (rented or bought, around 50 EUR for a canister + 50 balloons). Depending on temperature and moisture a latex balloon will last longer or shorter. The spare buoyancy needed for the nano air swimmer lasts roughly a day.
Tools:
- A scale accurate to 0.1g
- A felt tip marker pen
- Scissors
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When using the OrangeRx R415 receiver, you probably already picked them up together with their counterpart MOL125F-LEAD/19565 Micro Servo Connector Lead 1.25 Pitch - Female Plug (5pcs/bag), to make the extension lead.
Please keep me posted on your project.
Succes!
That’s roughly £65 + controller. If I wanted to make an army of 10 of these it would cost about £385.
Thank you very much.
First the shopping list for the version with HobbyKing parts:
From HobbyKing
R415/18827 OrangeRx R415 Spektrum DSM2 Compatible 4Ch Micro 2.4Ghz Receiver
HK-5320/17540 HK-5320 Ultra-Micro Digital Servo 1.7g / 0.05sec / 0.075kg
MINIJST-EXT5/9727 Mini Plug Extention for Micro Battery 10cm (5pcs/bag) SEE ALSO BELOW
N130.1S.25/11857 Turnigy nano-tech 130mah 1S 25~40C Lipo Pack (Kyosho, Eflite, Parkzone Etc)
You could order 1mm diameter carbon rod Carbon Fiber Rod (solid) 1x750mm from HobbyKing or find a 0,7-0,8 mm one in many RC shops.
From other sources:
DSM2 compatible transmitter (make sure your transmitter is DSM2)
3 mm EPP-sheet (at microflight RC shops or you can look for alternatives and test paper sheets of different thicknesses)
Balloon
Helium
Sewing thread
Superglue
Scotch tape.
Are you familiar with binding a receiver to a transmitter? The two larger pins on the receiver are for binding, they are NOT a power connection! To bind, connect the large pins electrically (with an alligator clip or a binding plug) and follow the instructions of your transmitter.
Connecting the servo to the receiver is straight forward. If you look at the connectors it is clear you can put them in only one way around. If the servo does not respond to the correct transmitter stick, simply try another socket on the receiver. If left and right are reversed, either do a servo reverse on your transmitter (if this function is available) or simply put the servo upside down on your balloon.
The battery connectors have the same pin spacing as the receiver sockets, but as there are only to contact instead of three you can put them in the wrong way! Check the servo leads to see which pins are the power (the red and brown one). The pin corresponding to the orange “signal” wire is not used for the battery (It might damage the receiver if you do). So the battery or its extension lead is attached to any receiver socket, keeping to the side corresponding to the power pins an leaving the signal pin alone. The + and – on the battery are normally the right way around. But obviously it is best to check. I read there are some batteries that are assembled the wrong way around. Checking is easiest with the extension leads described below.
You can connect the battery directly to the receiver, but it is much more practical to use extension leads. For the nano air swimmer it is practically mandatory in order to be able to move the battery for a good weight distribution. The lightest solution is a battery extension or servo lead extension made to order (shops specialized in micro flight can do that for you). The cheapest is ordering extension leads from Hobby King. They come at 2$ for a pack of five, but at 0,6 g for each 10 cm they are relatively heavy. You will need 3. With a fresh 11 inch balloon that is just acceptable. A lighter Hobby King solution is using male and female servo extension leads(MOL125M-LEAD/19566 Micro Servo Connector Lead 1.25 Pitch - Male Plug (5pcs/bag) = $1.20 and MOL125F-LEAD Micro Servo Connector Lead 1.25 Pitch - Female Plug (5pcs/bag). But this requires some soldering and insulating work.
Keep me posted!
The magnets, seem difficult to do. Repelling will only work if you have the magnets approach each other in the right path. Putting on more magnets, even tiny ones will put on to much weight. However simply having the balloons themselves bounce from each other is a kind of non destructive "fighting".
March 25th I'm planning on building some nano air swimmers and microblimps with a couple of friends. At that time we will be able to try out such things.
But I'm not sure what you mean with one LED for each direction the motor spins? It's a unmodified servo, so this might complicate things.
Or actually, I must admit I thought about a "battle version" and learned from some preliminary experiments that a tiny knife edge (like a piece of a small disposable utility knife) works far better than a pin.
The fish works well.
What about a condom? surly that would give you the best balloon? or maybe it breaths too much. Anyway I cant try this soon, but maybe one of you can?
Fill a condom with helium!
Is there a vote thingy for yours ?
Balloons are cheaper and easier to work with than condoms. For the fish I prefer the balloon shape anyway. But I have thought about using a condom for micro blimps. However, I have no idea yet on how long they last inflated with helium and if Hi-Float helps. From the little information I found it looks like helium filled condoms last less long than latex balloons. I should try it one day, but in the meanwhile any more info is indeed welcome.
The vote thinghy sadly never showed up. You can still rate my ible though.
I added some information on costs in step 1. Also see my answer to Cannonball2134 below.
The simple DSM2 transmitter I used can often be found second hand for around 20 EUR (from RTF sets).
I accepted! Then I went outside of the store, to put it in my car, and the wind stole my brand new air swimmer.. Fml.
When buying a helium filled balloon from the balloon shop, I usually let them attach a ribbon, as they are used to do when selling it to kids. At home I remove the ribbon.
Im into RC building/flying and this fish' gonna amuse my little daughter tonight-)
Thanx :-)
Do you have to replace the balloon when it goes down, or can you refill it?