jaredstrees
Well-known member
Well, she’s done and hoped for a maiden today. Little too gusty.
FT What Did You Do RC Today : Caution Offtopic At All Times
- Thread starter RCLucas
- Start date
jaredstrees
Well-known member
PsyBorg
Wake up! Time to fly!
Yer gonna need a bigger boat.
All i did was burn 20 dvds of old flight footage to clear some space. My 2tb drive had 89mb left AFTER scheduled defrag the other night.
jaredstrees
Well-known member
thank Psy. But my wife decided today that She wants a Jeep. So another chapter to unravel! Doubt the airplane trailer is gonna materialize first!
I totally blame @GEORGELCBLACK for this because his thread on building a thrust stand got me hankering to do an electronics / programming project. There hasn't been a piece of foamboard cut or glued in my garage-aboratory for the last few weeks while I tinkered with this thing and finished the software, and I have not been as engaged with the community as I'd like - but thankfully it's basically done now - a fully instrumented (kinda) and automated thrust stand.
Works better than it looks.
Close up of the load cell and beam-break RPM meter...
Close up of the breadboard. Got a 5V regulator, infra-red Rx/Tx RPM sensor, 6 voltage dividers for monitoring the individual cells up to 6S, hall effect current sensor, and instrumentation amplifier made up with two LM358s for the load cell, potentiometer control of the ESC, and yep - thats a pitot tube for airspeed (hope to use it for EDF thrust tube testing).
And here is the software in action during a pre-programmed run - basically you can set up a run with various throttle levels at various times and it will run it automatically and record the data when its done.
Then you can analyze the data afterwards, looking at different parameters and overlaying data from different tests.
Hard to describe this as a tool more than a toy - I had a lot of fun playing with the electronics and software. Will post the software (executable and source) a little later.
DamoRC
Works better than it looks.
Close up of the load cell and beam-break RPM meter...
Close up of the breadboard. Got a 5V regulator, infra-red Rx/Tx RPM sensor, 6 voltage dividers for monitoring the individual cells up to 6S, hall effect current sensor, and instrumentation amplifier made up with two LM358s for the load cell, potentiometer control of the ESC, and yep - thats a pitot tube for airspeed (hope to use it for EDF thrust tube testing).
And here is the software in action during a pre-programmed run - basically you can set up a run with various throttle levels at various times and it will run it automatically and record the data when its done.
Then you can analyze the data afterwards, looking at different parameters and overlaying data from different tests.
Hard to describe this as a tool more than a toy - I had a lot of fun playing with the electronics and software. Will post the software (executable and source) a little later.
DamoRC
Thanks!
The software can plot basically any parameter versus any other parameter. Thrust vs RPM not a problem or Thrust per Watt consumed. Efficiency requires that the mechanical power output be measured by including torque load cells in the design and I have not added them to mine, but the software supports it. The software also will produce "Calculated" mechanical power output based on the moment of inertia of the propeller and the acceleration of the motor/prop combo, but its not a great measure for efficiency. It can be used to characterize the motor with a flywheel, basically it can operate as an inertial dyno.
DamoRC
It's the difference between output and input power that burns a motor. High current is no problem as long as you have high efficiency, or the other way round, low current can burn a motor if you have low efficiency. The problem is that by measuring thrust, you have to take into consideration propeller efficiency, so not easy to get the motor's actual output power.
jaredstrees
Well-known member
Still waiting on my radicalrc stick 400 for the balsa build along, so I threw together a viggen. She will hopefully maiden this weekend, and if all goes well she'll get some colors.
Haven't been building, but have been flying. Tim took some vid this weekend of the polymycrophobia edition FT Edge 540 (with some incredible 3D action....not) and the Tigercat. Still lovin' the Edge - my favorite plane - can cruise around soooo slow. And the Tigercat is fun because she has so much power.
DamoRC
DamoRC
Tench745
Master member
I heard a 3D aerobatics routine referred to as "an aerial ballet." But I've decided that "aerial krumping" is a far more accurate description and 3D aerobatics shows should be advertised, run, and billed as such. I think it would actually make them a lot more interesting.
SlingShot
Maneuvering With Purpose
Fancy!
Scooter The White Rabbit
Active member
Um, any one know of any clubs in the Willamette Valley of Oregon that will answer an email about new members? I went through AMA site and then emailed... NOTHING. I have heard from a work contact about a private air park out in Hillsboro. The owner I heard is nice. the next chance I get, heading over there.
jaredstrees
Well-known member
Got a chance for two maidens today. Little windier than I’d like but couldn’t help myself.
New viggen flew great. Needed a little down trim but she’s earned some colors.
3D northern pike was next. Little harder to launch but she flew! Actually flew really well. A little too well. I could not get this plane down! She floats and floats and floats. So after the third attempt I thought I had it, then realized I didn’t have enough room. As I tried to pull up she stalled. The crash was spectacular. Foam board just doesn’t crash like plastic does!
So it was my first attempt at a 3D printed plane and I’m happy with how it turned out. Got another printing right now.
New viggen flew great. Needed a little down trim but she’s earned some colors.
3D northern pike was next. Little harder to launch but she flew! Actually flew really well. A little too well. I could not get this plane down! She floats and floats and floats. So after the third attempt I thought I had it, then realized I didn’t have enough room. As I tried to pull up she stalled. The crash was spectacular. Foam board just doesn’t crash like plastic does!
So it was my first attempt at a 3D printed plane and I’m happy with how it turned out. Got another printing right now.
jaredstrees
Well-known member
Sorry for the extra pics. Not sure why that happens when I use my phone.
nhk750
Aviation Enthusiast
I taped up my Sportster after a bad nose dive crash. I used my gorilla hands to smash it back into shape and then use a whole lot of packing tape to secure the nose back into position. I think it will fly again...This plane has been through hell and back again, but it just keeps going...although this may be the last straw for it...As you can see the tail section already broke off a long time ago...Hot glue and tape does wonders for these crappy foam board planes...
jaredstrees
Well-known member
I’m going to reprint the whole thing. There were some parts that didn’t print great. I figured for a first go who cares and slapped it together. I was pleasantly surprised at how well she flew. She could slow down to a crawl and then turn up the speed and haul butt. Nice plane.
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