Nitrous Oxide Hybrid

They have a different sound from the standard solid fuel rockets, and they burn brightly into the sky like a shooting star.

To take full advantage of Flickr, you should use a JavaScript-enabled browser and
install the latest version of the Macromedia Flash Player.

Comments

Mark Strozier says:

Mmmmm. Home-built rocketry porn.

Has the folks from Homeland Security given you guys any problems?
Posted 51 months ago. ( permalink )

They shut the high power motors down for a while, but then they mellowed out.

They also leave some undocumented regulatory gems to discover... e.g., GPS chip sets have embeddded code so that they stop operating when they notice that they are going real fast. So you can't use an un-hacked chip set to build a cruise missile...
Posted 51 months ago. ( permalink )

biotron says:

ha ha! probably a very good thing. :D - sorry, the laughing gas is making that funnier than it should be...
Posted 51 months ago. ( permalink )

The Rocketeer says:

Wow, that's the first time I've heard about that feature of the GPS chip sets. Very interesting... and smart.
Posted 51 months ago. ( permalink )

NothingToDeclare says:

To my knowledge GPS chip sets do not have embedded code to fail at high speed. What does happen is that most consumer grade systems rely on receiving the same (or nearly the same) reading several times in a row from the satellites to ensure that it's not a corrupted or garbled reading. The value of "nearly the same" is calibrated so that it works right in most consumer applications, like walking or in a car (less than 100 mph or so). When you move faster than that, then the consumer grade GPS never thinks it got good data from the satellites and never gets a lock on it's current position.

Most HPR rockets move much faster than that.

You can argue whether this is a bug or a feature, but it's certainly not a "regulatory gem". It's much harder to design a GPS unit that can track satellites correctly while moving at mach speeds or better, so the vendors don't bother unless the application requires it. When was the last time you were mountain biking at Mach 1?
Posted 51 months ago. ( permalink )

jurvetson says:

thanks! The GPS limits make sense. But I wonder if both phenomena are true. I am not an expert on this, so I double checked with my source from this weekend. Here are the specifics from the GPS FAQ archive:

"1.8 What are the speed and altitude limitations?

The system has no inherent speed or altitude limitations (GPS has
been used on satellites for position determination), but the US
requires that commercial receivers be limited to operate below
about 900 knots and 60,000 ft. It is apparently possible to get
permission to bypass these limits for specific applications
(research rockets, etc.).

Garmin used to limit their non-aviation models (40 and 45 at least) to
operation below 90 knots. Above this speed, the receiver displays
an error message and stops updating the position. This is
apparently a marketing decision to force aviators to purchase the
more expensive aviation models which incorporate an aviation
waypoint database. They discontinued this practice with the
advent of their 12 channel parallel units (GPS 12/12XL/II+/III). "
----
The U.S. limitations come from Item 11 of the US missile technology control regime.

So, if I try to piece this together, sat lock drift comes from cheap correlators on the chip set, but there is also a limitation placed on commercial units where they report an error if the limits have been passed. Make sense?
Posted 51 months ago. ( permalink )

mrneutron says:

Garmin GPSes are not limited to speeds below 90 knots. I've got a Garmin Quest and a fast motorcycle and it's delivered reliable readings up to 129 knots.
Posted 51 months ago. ( permalink )

jurvetson says:

right, it says "They discontinued this practice with the
advent of their 12 channel parallel units"
Posted 51 months ago. ( permalink )

Zippy the Pinhead says:

Yeah, the GPS firmware basically looks at the readings, goes "that can't be right" and ignores 'em.

There's a guy with Portland State Aero Society who wrote a new GPS firmware as his Master's project.

gps.psas.pdx.edu/
Posted 51 months ago. ( permalink )

Rawketcato says:

gas passers, gotta love em
Posted 49 months ago. ( permalink )

Would you like to comment?

[?]

	jurvetson's photostream
		3,044 uploads

This photo also belongs to:

	Rockets (Set)
		550 items
	Part of: Rocket Launches

	XPRS (Set)
		81 items
	Part of: Rocket Launches

	Desert (Pool)
		0

	The Secret Life of Technology (Pool)
		0

	Rocket (Pool)
		0

	DANGER! (Pool)
		0

	A Mechanical View (Pool)
		0

	Lumix (Pool)
		0

	Memories of Great Places! (Pool)
		0

	Physics (Pool)
		0

	1000 Views (Pool)
		0

	2000 Views (Pool)
		0

	5000 Views - [ © Plz Read Rules ] (Pool)
		0

	1500 views (Pool)
		0

	2500 Views (Pool)
		0

	The World Through My Eyes - Post 1 / Comment Any 1 (Pool)
		0

	8000+ Views - [ © Plz Read Rules ] (Pool)
		0

	Underground Begat Dogtown Ink (Pool)
		0

3 people call this photo a favorite

Additional Information

Some rights reserved Anyone can see this photo

Taken with a Panasonic DMC-FX7.
More properties
Taken on September 24, 2005
Viewed 9,755 times

Add to your map

Yay location removed

...

(Some formats are OK.)

Or, remove it from the map.

Go to the map

You	Sign in \| Create Your Free Account
Explore	Places \| Last 7 Days \| This Month \| Popular Tags \| The Commons \| Creative Commons \| Search
Help	Community Guidelines \| The Help Forum \| FAQ \| Sitemap \| Get Help

Nitrous Oxide Hybrid

Comments

Mark Strozier says:

jurvetson says:

biotron says:

The Rocketeer says:

NothingToDeclare says:

jurvetson says:

mrneutron says:

jurvetson says:

Zippy the Pinhead says:

Rawketcato says:

Would you like to comment?

Tags

Additional Information