THIS BLOG HAS MOVED

To www.gravityloss.com.

All the old posts have been moved there too. This old gravityloss.wordpress.com site will stay on for a while.

Music: Racer X – Technical Difficulties

Paul Gilbert’s made a nice song here and plays it well. The production might be better, but I like the melodies and the joyfulness.

Can I have Linux with that?

Apple’s Iphone, the various Google Android phones by Samsung, HTC and probably others, and Nokia’s Symbian phones are fighting on the smart phone market. As far as I know, Iphone is “closed” and you can only download those apps that Apple lets you have. Android lets you use any apps, and I assume Symbian is similar, though I’ve heard it’s old-fashioned. I don’t have real experience with any of these phones.

What’s really missing from the palette is an open source OS.

Well, there is one, Nokia’s Maemo, nowadays called MeeGo when they started co-operation with Intel. Only one phone, N900 uses it currently. I’m waiting for the next one, N9. Just look at a source example. All graphical development is done with Qt. It’s apparently not sucky since even XFLR5 managed to move into it quickly.

–

I’m using Linux at home, Windows at work and a Mac every now and then, like when the Windows is acting up every day or when I’m not at home. So this writing comes from a Macbook.

I hate Windows’ instability and sucky performance, Apple’s quirks and desire to do things differently (how do I get {} brackets on this keyboard?) and Linux’ need to fiddle with configs to get things to work.

I love Windows’ hardware versatility and choice of programs, Apple’s “things just work”* approach to software and hardware and Linux’s powerfulness and openness.

As a phone, I’m using a Nokia 6310i from 2002. The battery lasts more than a week and the user interface is snappy. It has a monochrome display. Hope N9 will be ready soon. You could run Dosbox on N900. Irssi. XFLR5. Just anything. In case something goes wrong, Android will be my fallback option.

*who ever thought that waking from sleep mode should take 15 to 45 minutes,
or connecting to a wireless connection should take forever and require ten
different cross-preventing logic levels? That every week you should
download updates that would require long installing times and reboots?
That the additional desktop room should switch from the left to the right side...
Apparently, someone at Microsoft, but nobody at Apple. I don't think it's
great innovation, it's just making things not suck.

Vesireittejä

If the city flooded – the water routes would allow escaping

Airbags, parachutes, Rogallo wings and all that

NASA of the sixties reminds me of the Armadillo Aerospace of today.
Drop tests, I think an F-111 model and various parachute, parawing and Rogallo wing things.

Airbags, landing rockets, landing gears (Dyna-Soar like rig)

Thank you NASA CRgis for another video blog day, one of many more to come!

Random video blogging

Modern manufacturing technologies enable strange shapes and could produce unconventional pumps. What is good for small scale rockets if turbines and centrifugal pumps have too much tip losses?

Rotary engines have vastly better power to weight ratios and vibrate less than piston engines. They’re also expensive and hard to build (cue modern manufacturing again). Here is one demonstrated in a paramotor, Parajet Cyclone using a Rotron engine. Love the music.

Spaceshiptwo – First Glide

Watch in high res at youtube. White Knight Two doesn’t look so large span after all. Spaceship Two is pretty wide with its outset elevons and the WK2 outer wings need to have the engines so there’s not much wing outside with the single purpose of lifting (or stopping the tip vortex). It seems both planes are really light too. Carbon fiber throughout. SS2:s wheels are really tiny. They have gone for minimum dry mass. The landing speed doesn’t seem huge even with its low aspect ratio. Maybe the size misleads. The landing is very smooth.

Of course the couple climbs out very fast even with gear out since SS2:s tank is empty and it doesn’t have the solid fuel onboard either.

I’m reminded of the lifting body research of the sixties. Who says we aren’t experiencing the golden age of aerospace right now? There’s happening interesting stuff left and right now, most of it in the more modest programs.

Helo Speed Records

This is becoming an aerospace video blog. 🙂

The eighties

Versus the teens

Westland Lynx only reached 90 m/s while X2 is doing 130 m/s. The ability to let the rotor spin slowly since only the advancing blade needs to lift in a counter rotating rotor allows the X2 reach a high speed.

Parawings and Rogallo wings, again

Inspired by Michel Van (not Scott Lowther as mentioned earlier) at Secret Projects, who ran into the Gemini inflatable Rogallo wing test videos that are now available (not embeddable so linked only). There are parafoil systems for airdropping stuff, though they don’t seem to be doing flares or line pulls to soften the impact:

And if somebody says parafoils are not maneuverable, I give you a Russian self built RC parafoil:

Speaking of rocketry, a member from the local hybrid group said they have found out the probable cause of roll control problems: the forward fins that were put on the rocket for roll control cause huge vortices when deflected, so that they effect the main fins far aft and the effect might be the opposite from intended.

Gravity Assist Competition

Or The Space Game, by ESA.

Minimize delta vee by moving the planets around (this changes the probe's arrival time at the planet). This shows my best solution so far, with some playing one evening, about 13 km/s

This is a nice javascript webpage where a probe is shot from Earth to Jupiter with gravity assists at Venus (twice), Earth and Mars. You try to achieve the lowest propulsive delta vee. You decide when the spacecraft arrives at each encounter and the program basically calculates the rest. It’s quite a nifty little piece of Javascript, the future of web applications is like this. It works fine with Chrome on Linux at least. Probably IE will have problems but who uses that anyway?

I’m ranked at #39 at 12.74 km/s… Far behind the gurus who get below 10 km/s readings! There are apparently some prizes for the top three, but I think people are in it for the fun of it.