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R&D Blended wing body with birds tail tests – Litreous A & B

I’ve had some ideas bouncing around in my head about the combination of blended wing bodies, birds tails, anhedral and spanwise lift distribution. These are some attempts at finding a balance between all of the above.

I’ve been watching various different sorts of birds tails recently and realised several similarities. Also thinking about the F-111 down at the Evans head museum. The people down there were pointing out that the British had made the entire tail plane change AOA thus making sonic possible. ‘Twas just unfortunate that the Americans used it first. Still it was a British realisation.

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Redious Maiden – Quick one day scratch build and fly.

Redious is an attempt to make a plane for beginner flyers. The air frame was shaped in just under 3 hours. Attaching the control surfaces and electronics was about another 3 hours. I started in the morning and was flying by the afternoon. We had discovered that 50mm thick EPS foam is incredibly strong without any laminates.

The main wing is just a single rectangular piece and the fuselage are just 2 more pieces of 50mm EPS. The control surfaces are 5mm thick triple ply foam board. The whole thing is shaped with a surfoam and sandpaper.

If you do happen to snap the wing in half it is easy and cheap to repair. You can just do a “rough as guts” finish and it will still fly. So no stressing about denting that perfect leading edge you spent hours refining. Of course you could spent another 3 days sanding and finishing to make it perfect and it will fly better. Personally I like to ask if that adds any more fun to flying. Sometimes it does, most of the time not though.

Music –> Flume – This song is not about a girl.

Flying starter setup

Building on the Redious design above and getting into flying wth a low overhead, the best starter kit I can find at the moment is:

Gliders

This list is optimised from buying in Australia.

  1. Transmitter and receiver kit (TX/RX) – Turnigy i6 (which is a rebadged Flysky i6)
  2. 4 * AA batteries for your Transmitter (TX)
  3. A 4.8v power pack
  4. An EPS foam sheet 2400 * 1200 * 50mm. Available from Ballina Fibreglass here in Ballina. You’ll have to look up foam suppliers where ever you are. In cities you’ll get sheet cut to thickness. They usually get their foam in bulk from CSR or DUNLOP (I think).
  5. Foam board from most Signage supply places. Usually comes in a 2400 * 1200 * 5mm sheet
  6. Gaffer tape
  7. Hot melt glue gun – This is a golden piece of equipment.
  8. Multihesive(preference) or PVA glue
  9. 1.8mm galvanised fencing wire
  10. Linkage stoppers.  These are by far the easiest to use of the many I’ve tried.
  11. Control horns.  These are by far the easiest to use of the many I’ve tried.
  12. Locktite
  13. 2 x servos DS-939MG
  14. Surform for mowing out the foam

Base extras

  1. A battery charger B6-AC

Notes:

The foam sheet above will probably make 3-4 planes. So you have spare for  WHEN you crash it. Yes you can get in the air more cheaply initially, but when you kill your wing it will be harder and more expensive to repair. These planes will be less breakable. Also they’re a bit bigger so they’re less twitchy and you are less worried about weight.

Try find the parts that are in the Australian warehouse so you’re not waiting 2months for things.

For methods on building and repairs see the Gemot manual. It’s a more advanced plane, but the techniques you need (except for surforming) are in there.

Also foam board flat pack planes from flitetest are easy, but will take 3months to get to Australia via standard postage.

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Dubious GY-85 boards and HMC5883L fix

I ordered 3 different GY-85 boards from 3 different suppliers to find that all of them had the wrong magnetometer in them. Some even advertised their product with the HMC5883L chipset on them, but when they arrived they where the QMC5883L chipset.

After all this effort to find something without the shipping cost / time from the USA I decided to just get the HMC5883L individually and attach it to the I2C bus of the GY-85 board. The individual boards is called the GY-271. I found this supplier in Chullora in Sydney:
GY-271 HMC5883L
It worked just fine and now the head tracker is working.
You’ll see in the image below that the Honeywell HMC5883L chip is defined with the markings
L883
2133

Where as the 6th page of the QMC 5883L manual shows the markings something like
DX
5883
XXXX

QMC5883L datasheet

HMC5883L datasheet

Using the GY-271 compass board by itself

(Also posted in RC groups)