Super Cheap RTF R/C Drenalyn 
Tuesday, January 30, 2007, 06:23 PM - Flying Contraptions
The Drenalyn is a popular indoor R/C design in France (I built many such planes myself, see here, here, and here).

It was only a matter of time before a Chinese toy company would produce a low-cost ready-to-fly version. I actually approached the Air Hogs people a few years ago with the PMAV concept, but they were not interested.

Chinese R/C toy company Hongxin Toys is selling a Drenalyn-like R/C toy, which they call a "Kite Airplane". The widget is available in the US from at the incredibly low price of 70 bucks (complete, with transmitter, battery, and on-board LEDs for night flying!).

Most low-cost R/C toy planes are boring 1 or 2-axes types (without ailerons), but this one has elevons, and is probably fully aerobatic.

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Francis Plessier: Pioneer of Unusual Miniature Flying Contraptions 
Tuesday, January 30, 2007, 05:57 PM - Flying Contraptions
You probably figured out by now that we are fond of flying pancakes at Yann's Techno Toys. R/C plane builders have long built fun planes with low aspect ratio or circular wings. The first example I ever saw was Plessier's "Soucoupe", a circular wing built by legendary French modeler Francis Plessier in the mid 1970's. Plessier flew a Soucoupe (with a smiley face painted on the bottom side) at the annual Cirque des Cigognes in Bretigny. I built my first Soucoupe in 1975, right after seeing his. Francis Plessier always came up with crazy ideas for the "Cirque", such as a flying dog house (below), a flying iron (below), flying lawnmower, and many others. His ideas have been ripped
off (often without proper credit) by airplane kit companies in the US.

Pictures of Plessier's Soucoupe, Iron, and Dog House are available at this page.

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Desoldering Surface-Mount Devices 
Tuesday, January 30, 2007, 04:12 PM - Electronics
Instructables shows a nice method for desoldering surface-mount devices . The idea is to bend a piece of copper wire all around the SMD so that it touches all the pads. Heating the wire with an iron distributed the heat to all the pads.
Watch the video.

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L'Hydroptere: 47 knots in a flying sailboat 
Sunday, January 28, 2007, 11:38 PM - Misc TechnoToys
L'Hydroptere, a radical new sailboat design, has exceeded the speed of 47 knots during its third test this week. Last week-end, l'Hydroptere managed to run one nautical mile at an average of 41.74 knots (a non-official record). The pictures and videos of the Hydroptere flying on its hydrofoils are spectacular.

This the 5th version of the Hydroptere, a concept originally proposed by legendary sailor Eric Tabarly, and developed over the last 15 years by Alain Thebault and his team.

They are hoping to beat the 500 meter speed record (48.7 knots, held by Finian Maynard on a windsurfer), the 1 NM speed record (39.97 knots, also held by Maynard), and to eventually circle the globe in less than 40 days (the current record is 50 days, held by Bruno Peyron).

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Small Form-Factor PC for Cars and Mobile Robots 
Thursday, January 25, 2007, 01:53 AM - Robotics has a small form-factor barebones PC for $400. The size is 21x26.5x6.6cm, which is a bit too big to fit in those new hackable Roombas.

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USB Digital Oscilloscope w Open Source Software 
Thursday, January 25, 2007, 01:46 AM - Electronics
SyscompDesign is selling a USB digital storage oscilloscope for $190, which comes with open protocol specs and open source software on Linux and Windoze. It has 2 channels and can go up to 20 million samples per second.

Finally, someone has realized that hardware hackers are also likely to be Linux/open source freaks. It took a while.

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Electric Helicopter Beginner's Guide 
Saturday, January 20, 2007, 02:46 PM - Flying Contraptions
This UK site has an excellent tutorial on electric helicopters by Toshiyasu Morita. The tutorial is available in English and French.

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Excellent Article Series on DIY Brushless Motors 
Friday, January 19, 2007, 07:08 PM - Flying Contraptions
There is an excellent series of tutorial articles on the design and performance of brushless outrunner motors at site of the Southern Soaring Club. The articles give all kinds of details on how to morph CD-ROM and hard-drive motors into airplane motors (click on "articles from Southeasters, and look for the article series by Brian Mulder).

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Reasonnably Competent Pilot flying an SU-30 
Tuesday, January 16, 2007, 11:36 PM - Flying Contraptions
My friend Steve Crandall pointed me to this video of a Sukhoi 30 being flown by (according to Steve) a "reasonably competent pilot". I didn't realize they could put those SU-30 in reverse.

UPDATE: IraqiGeek tells us this is actually an SU-35, and points us to another nice SU-35 video]here[/url].

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Rubber Toughened CA glue R0ckz 
Tuesday, January 16, 2007, 10:42 PM - Flying Contraptions
I have become very fond of a new type of high-viscosity cyanoacrylate glue that contains what the manufacturer calls rubber (not sure it is rubber). It bonds in 15-30 seconds, has ultra gap filling capabilities, and works very well with carbon fiber, and extruded polystyrene (Depron and such).

One is the Flash Black Rubber-Toughened CA made by NHP ($5.75 at BP Hobbies), another one is the IC-2000 made by BSI Adhesives. They are both foam friendly and respond to foam-friendly accelerator.

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Powerful/lightweight speaker 
Tuesday, January 16, 2007, 12:07 AM - Electronics
Several people (my dad and I among others) have been experimenting with engine sound generators for electric R/C airplanes. Those generators make the plane produce the sound of the real plane. With all the chatter about this topic, there is a need for a compact, lightweight, but powerful loudspeaker that can be mounted in an airplane. It needs to be powerful enough to be heard from the ground. The necessary power seems to be around 40 Watts.

Some of us have so far been using cheap 10cm speakers, such as the Visaton R10S-4 (4 Ohms, 20 Watts, 10cm diameter, 150 grams).

Interestingly, Blaupunkt seems to have a range of powerful and lightweight speakers, such as the THx 402: 10cm diameter, 40W continuous (120W peak), 4 Ohms. The magnet weight is 30 grams (not sure about the total weight).

The only problem is that it retails for $55 to $90 (compared to about $10 for the Visaton).

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United Hobbies: Real Cheap R/C Stuff direct from Hong-Kong 
Saturday, January 13, 2007, 02:49 PM - Flying Contraptions
United Hobbies is an on-line hobby store located in Hong-Kong that sells direct to customers around the world. They have all kinds of Chinese-made R/C stuff at unbelievably low prices. For example a complete helicopter with collective pitch is $101 (ready-to-fly, with radio). They have ultra-low price brushless outrunner motors, and LiPo batteries, e.g. a 3S 4100mAh pack for $52.

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ThrustPac: propeller-powered bike 
Friday, January 12, 2007, 11:13 PM - Misc TechnoToys
The ThrustPac is a backpack with a 4-stroke engine powering a ducted fan. The mid-range model features a 1.5HP, 35cc engine, can propel a bike at 40km/h, and costs about $900. The only problem is the loud noise, kinda like flying a 1/4 scale model airplane in the street....

Modern outrunner brushless electric motors are powerful enough to replace those noisy gas engines, and way more quiet. It should be possible to have a decent range with LiPo batteries.

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Foldable Indoor 3D biplane 
Friday, January 12, 2007, 12:14 AM - Flying Contraptions
This nice (but expensive) biplane kit is not made of Depron or any other kind of extruded closed-cell styrofoam, it's made entirely of carbon fiber rods and plastic foil. The plane can be taken apart and folded flat.

There is no aileron: the whole wing pivots. My experience with flat pivoting wings for small gliders has been a disaster. I suppose having a propeler blowing on the wings solves the brutal stalling behavior I have observed.

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Amazing Lego Car Factory 
Wednesday, January 10, 2007, 07:19 PM - Robotics
There is an amazing video of an automated car factory built with Lego Mindstorms on YouTube. The whole setup is huge. I couldn't count how many RCX bricks are used, but it seems like a lot. Unfortunately, there doesn't seem to be any other web site that describes the system.

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High Power LEDs for cheap 
Tuesday, January 9, 2007, 12:41 AM - Electronics
High-power LEDs have been available for some time, but most web stores have huge markups on the price. Lumiled Future Electronics sells them for (relatively) cheap. For example, their 3 Watt Luxeon III Stars are $3.50 to $4.50 depending on color.

Instructables has a tutorial on an RGB light controller that uses them.

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