---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Sat 06/04/05: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:42 AM - Re: Blind encoder readout (Leo Corbalis) 2. 11:39 PM - LED-based logo lights (chad-c_sip@stanfordalumni.org) ________________________________ Message 1 _____________________________________ Time: 09:42:46 AM PST US From: "Leo Corbalis" Subject: Re: Avionics-List: Blind encoder readout --> Avionics-List message posted by: "Leo Corbalis" Do it the easy way! Call ATC and ask them what your transponder is broadcasting. They can read it off the moniter as if the altimeter setting was 29.92. Set your altimeter to 29.92 to get a valid check. When you get your biannual transponder check, get an altimeter check for every 1000 ft. The encoder can be adjusted if necessary. Leo Corbalis P.S. DO NOT CALL WHEN THE WEATHER IS STINKY AND THERE AIS LOTS OF TRAFFIC ! >> Is there as way that I could read the altitude that my encoder is >> transmittitng. Might I also be able to adjust the encoder to read the >> correct altitude. > > Remember that the transponder puts out your pressure altitude. No > correction for the local barometric pressure is applied in the aircraft. > It's done on the ground. > > That means that anything you build for comparison with your altimeter will > have to include the appropriate arithmetic. > -- > --> The best programming tool is a soldering iron <-- > > > ________________________________ Message 2 _____________________________________ Time: 11:39:22 PM PST US From: chad-c_sip@stanfordalumni.org Subject: Avionics-List: LED-based logo lights Z-USANET-MsgId: XID215JFeglv0443X29 1.25 RCVD_NUMERIC_HELO Received: contains an IP address used for HELO --> Avionics-List message posted by: chad-c_sip@stanfordalumni.org My family is currently building a Lancair IVP-turbine and I'm tasked with doing all of the electronics and lighting. My father (the primary pilot) wants "logo" lights - lights that shine on the vertical stab. to improve visibility at night. The only place I really have to mount such lights is in on the inside surface of the winglets which aren't themsleves very thick. Given that, I've been thinking that an array of white LED's might be a good way to get the amount of light I'm looking for while keeping the form factor very flat to fit inside the winglet. I'm considering using Lumex's SSP-LX6144A9UC high-intensity LEDs as the lights of choice (a PDF of their characteristics can be found at http://www.lumex.com/product.asp?id=1006182 - short version: 10 deg. double angle, 2 lumens total flux, 12 candella axial intensity, ~400mW). I can buy these at $22 ea. at Allied Electronics. I'm not 100% sure how many I'll need but I suspect I'll want more than 8 on a side. Ideally, I'd want a light with a double angle of 9 degrees. First, can anyone else suggest a white LED that has a higher intentisty in the angle I'm looking for at less money total? If we decide to paint the tail something like red I'll simply use a red LED as the logo light. Secondly, I've got a question about wiring up such devices. Usually when wiring an LED you put a current-limiting resistor in series with the LED and then put a bunch of such pairs in parallel. This helps to overcome the temperature/current correlation common in diodes (and bipolar transistors) that allows a single element in a parallel array to hog current and burn out first. However, I've got a 28v supply native to the aircraft and each LED is happiest with 3.4V. Could I simply put 7 of these in series with a small resistor to fix the desired current at 100-120 mA? That would give me 14 lumens per side on a surface a few feet high and wide. Would that be bright enough to make the tail visible to other planes from far enough away to matter? Thanks for the input. Chad Chad Sipperley Lancair IVP-turbine (under construction) Phoenix, AZ