The Silverlit Atlas

November 14th, 2008 captain

The Silverlit Atlas is the natural progression from the PicooZ. Extra buttons on the transmitter add forward motion control to the existing up/down and rotate left/right options. The box describes this as 3-channel control, but with no backwards option, it’s more like 2½.
The Atlas is also available as the Uranus which has led to much sniggering and many school boy jokes on various forums. The only difference between the Atlas and Uranus is a minor variation in the fuselage profile. For the rest of this article I will only refer to the Atlas.

Configuration

The size and configuration is very similar to the PicooZ. The fuselage is significantly narrower and the large gear wheel is absent. A two stage gearing is used instead which is compact enough to remain wholly within the fuselage.


The main selling point for the Atlas is the forward motion control. The mechanism to achieve this is connected below the main rotor. Two arms project down from the rotor to a circular ring surrounding the rotor shaft. Above the rotor is Silverlit’s now familiar propellor style stabilizer bar.

A copper coil sits in front of the rotor shaft. A current applied to the coil displaces the suspended ring, which combined with the action of the stabilizer, changes the flight geometry to generate the desired forward thrust.
 
The power switch and charging socket are on the starboard side of the fuselage.

Controller

The controller only differs from the PicooZ in two aspects: one functional and one cosmetic.
Functionally there are two buttons on the back that control forward flight. They are located where your index fingers naturally fall. Pressing the left button causes a small forward movement, the right a larger movement. For continuous forward flight press and hold them together.
Cosmetically, the controller has had a face-lift. It now has a 1950′s sci-fi fee with it’s triangular LED bulb and metallic silver panels.


As with all the other micro-helicopters smaller than the Gyrotor the flight battery on the Atlas is charged from the controller via an umbilical cord.

Airspace

Standard to this size of helicopter, the manual recommends a room of about 3m x 5m x 2.5m, free from drafts, bright lights and strong sunshine.

Flying

My first impression of the Atlas was that it did not handle as well as the PicooZ to the point that I got the PicooZ out to check.  I’d been flying the Palm-Z a lot and wondered if my helicopter skills were rusty.  The problem was definitely with the Atlas.  It wasn’t that it was uncontrollable, just that it lacked precision.  Where as I could land the PicooZ on coffee mat and fly it under a chair, the Atlas needed a dustbin lid and a table.  I put this down to the extra mobility of the rotor head.

Halfway through the first flight I decided to test the forward flight controls.  I pressing the left button for a short forward movement.  There was a delay and then the Atlas tipped forward for a second, moved about 15cm (6 inches) and then swung backwards and forwards like a pendulum.

Pressing the right button was similar, just with a longer forward movement: about 40 cm.  At the end of the movement it started descending sharply, dropping to the floor.  Adding power to the main rotor had no effect.  Following an immediate takeoff it was back in the air as normal.

For the final test both buttons were pressed together for continuous forward flight.  The Atlas started speeding around in large circles.  Control whilst holding the buttons down was difficult especially combined with the speed.  After a short sprint the Atlas again dropped to the floor.

During the next eight to ten flights this dropping behavior diminished to nothing as the Li-Poly battery became conditioned.  This behavior is typical and is seen in all of the micro helicopters as coarse speed changes during early flights.  The effect was more pronounced on the Atlas due to the extra current draw of the rotor pitching coil.  I had a four month period where I didn’t fly the Atlas and found that the dropping behavior had partly returned.

On some flights the motors unexpectedly cut out during the flight with a fall to earth.  Once recovered and relaunched, flying continued as normal.  According to the forums, the Atlas has a thermal cut-out to prevent damage to the electronics.

As direction control during forward flight was minimal, I followed the PicooZ’s example and added a little weight to the nose using Blue-Tak.  This gave a slow but constant forward motion, to which the (semi)controllable forward flight could be added as wanted.

Modding

The only mod I have made to the Atlas setup is to remove the spring from the main rotor control.  This was so I could explore the forward flight controls with the main rotor set for hover.  Although only a minor change, it proved useful enough that I kept it.

To remove the main rotor spring remove the four screws from the back and gently separate the two halves.  Make sure you keep all the buttons and switch covers that fall out.

Pulling the main rotor stick from its seating reveals an offset spring.

Removing the screw securing the spring allows it to be rotated out of the way.

After replacing the screw the sticks can be reseated before re-assembling the controller, ensuring all the small parts are replaced.

Conclusion

I find the Atlas difficult to recommend.  It may look better, but the “third” channel, does not live up to it’s promise and the lack of precision compared to the PicooZ leaves you feeling unsatisfied.

If your flying space is limited and you want to progress beyond the PicooZ then you might consider the Atlas, however I would suggest spending a little extra and skipping to Silverlit’s newer TandemZ-1 twin rotor (to be reviewed soon).

Facts and Figures

What’s in the box

• Atlas helicopter
• Combined infra-red transmitter and charging station
• Multi-language manual
• Spare tail rotor

You have to supply

• 6 x AA batteries
• Cross-head screwdriver in order to fit them.

Dimensions

• Main rotor diameter: 132 mm
• Fuselage length: 170 mm
• Height: 63 mm
• Weight: 12 grammes

Manufacturers Website

• Silverlit Flying Club
• Atlas Product Page

Available in the UK From

• Amazon
• Play.com 

Posted in 3 ch, Helicopter, Indoor, Modding, Review | No Comments »

The Hat Cam

July 7th, 2008 captain

I have been looking for a simple helmet/hat mounted camera system, so I could shoot video of the review aircraft in flight.  I looked at bullet cameras that are normally used for this purpose, but was put off by the need for separate microphones, battery packs and recorders.  There are a number of all-in-one systems available but they are either expensive or have poor video quality.

I wanted something that would be self-contained, robust and waterproof.  The Twenty20 VholdR looked promising, but the UK price was too high.  I then looked at digital compact cameras.  There are two brands that are advertised as robust and waterproof by Olympus and Pentax.  The Olympus models would only record 10 seconds of video at 640×480 so that left the Pentax W30 that would record at maximum quality until the memory card was full – about 40 minutes.  I also liked the fact that the lens and tripod mount were located centrally.

The next task was to mount it on a hat.  Unless I take it snowboarding, I don’t have a need for a helmet, but finding a suitably rigit hat was difficult.  In the end I found the Vitrex safety cap and the Scott International Bump Cap.  Both are baseball caps with a padded hard plastic insert, producing lightweight head protection without the need for a full helmet. My local tool supplier had the Scott.

The plastic insert provides excellent support for a camera mount.

The mount was formed from a large plastic washer I found at work.  It’s 72mm diameter and 3mm thick with a 19mm diameter hole.  I heated it up using a 300W hot air gun and bent it to a suitable angle. Once cooled, I drilled two 3mm holes for connecting to the hat insert.  The mount was then held in place against the hat and one of the holes drilled through.  This hole was used to fix the mount to the hat using a 3mm nut and bolt, before the second hole was drilled through.

After removing the mount, the hat insert holes were countersunk so that the bolt heads would be flush and not stick into my head.

 

The tripod mount screw was obtained by purchasing a quick release tripod platform and removing the screw.  You could also use a 1/4″-20 bolt if you can find a source.  So that the bolt would not fall out when the camera was not attached, I drilled a slightly oval 5mm hole.  The screw was them placed against the hole and then turned while pressing hard.  This caused the screw to cut a thread in the plastic.  With the screw right through it’s wasted portion is in the hole and so will rotate freely but cannot drop out.

The rubber washer was bonded to the mount after finding that the screw was bottoming out in the camera before attaining full tightness.

The whole system was mounted on the hat using M3 countersunk bolts with washers and nuts.  The bolts were initially too long, so I cut them back using a Dremel type multitool.

The first few attempts recording some flying footage highlighted some room for improvement.  The main issue was getting the hat on straight and level, so that the object was in the middle of the frame when looking straight at it. On one flight the helicopter kept disappearing off the frames left edge.

To fix this I borrowed a trick from the VholdR.  I purchased a small keyring presentation laser to act as a reference.  A mount was made by folding a plastic strip around the laser after softening it with the heat gun.  The holes were made using a hole punch.  An extra hole was drilled on the mount for a 4mm countersunk bolt to hold it firmly in place.

Now I could mount the camera on the hat and the hat on my head such that my point of interest was centre frame.  The procedure runs as follows.

1. Turn the camera on.
2. Point the camera at an object so that it appears in the centre of the LCD.
3. Press the button on the laser and see where the dot appears.
4. Twist the camera on the mount towards the dot.
5. Repeat steps 2 and 3 until the dot hits the centre of the object.
6. Switch the camera into movie mode if needed.
7. Place the hat on your head.
8. Look at the object.
9. Press the button on the laser and see where the dot appears.
10. Rotate the hat so that the dot points towards the object.
11. Press the shutter button and start filming.  Remember that the camera lens is 5 or 6 inches above your eye level when filming close up.

After some use, I found that the laser support had cracked at the sharp fold.  I would have preferred to replace it with aluminium, but was unable to source some locally.  Instead, I used some plastic strip that was thicker than the original.

Sample Video

The sample video below of the Palm-Z has been reduced in size and compressed from the original 42Mb MJPEG 640×480 quicktime file.

Final thoughts

I have been pleased with the results from the finished HatCam.  The only issue is the weight of the camera.  If the size adjustement is loose, then quick head movements can cause the brim to droop over your eyes.  This is rare however and easily prevented by keeping the adjuster tight.

An alternative would be to add a counterweight at the back of the hat, although the best solution would be a lighter camera.  One recent possibility is the new Flip Mino Camera which has a tripod mount and weighs a mere 95 grammes compared to 160 grammes fot the Pentax Optio W30.  It uses H264 video compression so the picture quality is not quite as good as the Pentax’s MJPEG but uses considerably less disk space.

Posted in Camera, Modding, Uncategorized | No Comments »