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Mar 13, 2015, 04:53 PM
2016 The Year for Air Shows
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Build Log

Flight Logger, Part II “1s Power Mod”

Finishing up some winter projects. The umx Radian has been fitted with a Flight Logger, measuring altitude & temperature during the flight time. The challenge is to maintain the weight penalty as low as possible.

Flight log from March 16, 2015
[best glide = 15 sec motor run to 147 feet AGL
with a 1 min 40 sec glide to 50 feet AGL
or an average of approx 1 foot descend rate per second]
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(click on picture to view larger)
for more Flight Logs, click here

Key Specifications:
Ultra Micro Y Harness for Single Battery FPV (SPMVC1101)
HobbyKing Altimeter
Price: under us$30
Dimensions: 21x13x5mm
Weight: 1.3g ~ 1.4g (sensor Only)
Working Current: ~ 7mA
Operating Voltage: 3.7 ~ 8.4v
Sampling Frequency: up to 8hz (sampled 8 times a second)
Optional Wireless Reader "Bluetooth to FlyDream Altimeter (Android system )" click here

Here is what was on my mind:

--> Update: Oh my, looked under the hood & realized the logger uses what appears to be Molex Pico Blade connector. Opens up a world of possibilities to shave a few grams off the weight - the "Y" connector also uses Pico Blade connectors.

--> The naked sensor weighs in at 1.4 gram, so that is the minimum weight penalty; however, we need some wire connections for the power

--> Here is the third revision I made. Very carefully removed the black & red wire from the logger & "Y" connector. Inserted the "Y" connector wires into the logger connector. Cut the white jumper wire, twisted, touch of solder, glue & shrink. Very light weight & can be powered with a tiny 1s battery if I want it in a bigger plane or heli. This mod takes 1.4 gram off revision II.
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Done! Logger & "Y" connector at 1.8 grams total
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So the final weight penalty for the Flight Logger system is:
--> secured with the shrink sleeve = 2.8 gram
--> secured with electrical tape = 1.9 gram
--> secured inside fuse = 1.8 gram

Below are my notes from revision II - 2015

--> First question was how to secure with the limited space. Decided to make a sleeve to hold the battery & logger to the plane (1.0 gram) or I could use a piece of electrical tape (0.1 gram). The deciding factor on what to use will be the landing site: grass or asphalt; temperature: hot or cold; & thermal / wind conditions.

--> The flight logger, modified with shortened wires, weighs in at 2.8 gram
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--> The battery “Y” splitter to power the logger weighs in at 0.4 gram
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So the weight penalty for the Flight Logger system is:
--> secured with the shrink sleeve = 4.2 gram
--> secured with electrical tape = 3.3 gram

--> The Mini Aviation 220mah battery weighs in at 6.0 gram
--> The E-flite 150mah battery weighs in at 4.1 gram

--> The All-Up weight with the Mini Aviation 220 is 10.2 gram (6.0 + 4.2)
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--> The All-Up weight with the Mini Aviation 220 secured with tape is 9.3 gram (6.0 + 3.3)

--> The All-Up weight with the E-flite 150 is 8.3 gram (4.1 + 4.2)
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--> The All-Up weight with the E-flite 150 is 7.4 gram (4.1 + 3.3)

I will make this a permanent addition to the umx Radian as last year I had some great flights but failed to attach the logger.
- last year's system was too cumbersome & heavy ~ 6+ gram & required 2 batteries
- revision II for 2015 = 3.3 gram
- revision III for 2015 = 1.8 gram

Flight Logger, Part I “The Bench Test”

2015 Flight Log Debrief Reports

--> The Altimeter Manual pdf is attached below

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Last edited by Red.Sneakers; Jun 06, 2015 at 02:47 PM. Reason: update
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Mar 16, 2015, 09:34 PM
Microbursts hurt.
snoopy's Avatar
Cool! I FPV my UMX Radian, had considered adding something like this and needed to keep it light. May touch base later this year to see how its working for you.
Mar 16, 2015, 09:52 PM
2016 The Year for Air Shows
Red.Sneakers's Avatar
Thread OP
Cool! FPV the umx Radian. We'll trade mods, very interesting. Had my son fly it for the first time today, I gave him one a few months ago. Once he starts going to the park with me, then I'll give FPV a go with a buddy box system. New year, new adventures.

I tried a set of FPV goggles at the WRAM show, got dizzy while standing. Lady said I need to be grounded by sitting down. Any comments on the 'grounding' issue?
Mar 18, 2015, 10:09 AM
Microbursts hurt.
snoopy's Avatar
Trading mods sounds like a good idea. I'd love to collect the data on the FPV flights for the Radian.

I eventually got used to it standing up, first few flights not a bad idea sitting down.

I have a small write-up on the UMX Radian on our flying site, but will probably add tot he thread here on RCG soon.
Mar 18, 2015, 02:09 PM
2016 The Year for Air Shows
Red.Sneakers's Avatar
Thread OP
Yea, I did not fly my Radian last year, will do this year & can not wait to put the logger in it. I had added a fire-wall and a shelf in the front of the cockpit to hold a max altitude sensor. I'll put the logger, powered with a small 1s batt, inside the shrink sleeve and Velcro it here.

One tip I have learned: to get the best results, let the sensor acclimate to the local temp (out of the sun) before connecting. Critical for cold weather, not so much in the summer when your car temp = +/- to the outdoor temp.

Nice blog on the umx FPV.

May 11, 2015, 08:54 AM
2016 The Year for Air Shows
Red.Sneakers's Avatar
Thread OP
Today is May 11, 2015 & HH said the Ultra Micro Y Harness for Single Battery FPV (SPMVC1101) needed for this mod should be back in stock in about a week. It took them a long time to get it back in. Ordered 4 so I should be ok for a few projects.

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