Jack Crossfire's Blog – March 2010 Archive (5)

THIS WEEK IN AEROSPACE

THE WAR ON ALUMINUM, MARCY 2 IDEAS



AIRFRAME OPTIMIZATION HELL



Mainly, going from something that flies to something worthless hoping to someday get something more efficient flying again. The fact is Marcy 1 didn't have enough lift to do what She needed to do.







Got a wing from a discontinued glider… Continue

Added by Jack Crossfire on March 26, 2010 at 11:30am — 11 Comments

Michael's Dispatches 4 U

On http://www.michaelyon-online.com/warthog.htm Michael Won wrote:



UAVs are very useful, but come with sharp limitations. They are great hammers when you need a hammer, but they’re still hammers when you need a wrench. For example, UAVs can’t guard bridges against suicide bombers. They have limited, pinprick firepower other than for small targets. They are useless in poor weather. UAVs are but…
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Added by Jack Crossfire on March 23, 2010 at 11:00am — No Comments

This week in aerospace

PROP ADAPTOR TERRORISM, INDUCTOR INSANITY, THERMOPILE TERRORISM, WHAT SLOW

ATTITUDE ESTIMATES MEAN, LAST WEEK'S VIDEO FLIGHT



PROP ADAPTOR TERRORISM



These aluminum GWS prop adaptors are ridiculous. Lately they started stripping before getting anywhere near the required tension. Down to threadlock on plastic again.











Forget about those tiny set screws. Use… Continue

Added by Jack Crossfire on March 19, 2010 at 11:18am — 2 Comments

NOISE NOISE NOISE

Marcy 1's flight time is horrible with POV. It's declined from 10 to 6 minutes.



She's got radio lockups with the chip radios. That's coming down to a hardware state which can't be corrected by resetting the hardware. Connecting reset to Vdd reduces the lockups but adds a huge amount of noise to the thermopile readout. The logic pins on the MRF49XA put a huge amount of noise into your power supply.



The thermopile is down to power line noise. This isn't a problem when they're… Continue

Added by Jack Crossfire on March 12, 2010 at 11:30am — 3 Comments

THERMOPILES, GYROS, & LIGHTS

So went through many boards trying to get useful results from thermopiles. The trick is they have the teeniest tinyest voltage changes & very slow responsiveness. Work around the responsiveness through extreme amplification.



The unamplified thermopile was immediately busted. Not enough current.







Straight 2:1 amplifier. The voltage changes were too small.…





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Added by Jack Crossfire on March 5, 2010 at 12:00pm — 8 Comments

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