Janis Putrams
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Vibration analysis

Started this discussion. Last reply by Janis Putrams Jun 15, 2015. 4 Replies

Hi,My transmitter has not arrived yet so I have been trying to get deeper understanding about brushless motor and prop vibrations.I did not have any success using phone for vibration monitoring so I…Continue

Tags: brushless motor, propeller, vibration

 

Janis Putrams's Page

Latest Activity

Janis Putrams replied to Forrest Frantz's discussion Max mag field length--Why A Max?
"The way I see it is that mag sensor is needed for drone to know the absolute direction at any time in flight. The problem is that mag sensor is susceptible to outside interference and therefore is not reliable. A low drift gyroscope could be used…"
Feb 15, 2017
Janis Putrams replied to Forrest Frantz's discussion Max mag field length--Why A Max?
"We had issues with mag field as well. Eventually the decision was to use low drift gyro."
Feb 12, 2017

MR60
Forrest Frantz left a comment for Janis Putrams
"Thanks for sharing the videos. Fricking unreal!!!  Wish I'd seen this earlier (got too busy at the end of last year). Looks like you got Yaw solved and the ship going and solved the problems.  Well done. Where can you find water that…"
Jan 26, 2017

MR60
Forrest Frantz left a comment for Janis Putrams
"believe it or not, i just checked my mail. really cool.  love the design.  Simple, light, redundant. and like the way you protected the props.  sometime i'll show everyone a simple and extremely light method of rejoining carbon…"
Oct 12, 2016
Janis Putrams left a comment for Janis Putrams
"Great that you liked the video. The bigger vision for me is that I think that air is very much underused. There are big planes and small copters but not much in between. My assumption is that it is generally because of the cost of flying machines…"
Jun 20, 2016

MR60
Forrest Frantz left a comment for Janis Putrams
"Janis - You are insane!  Completely off the edge of the envelope (an American expression). Absolutely loved your video.  So what do you want to know? How can I help?"
Jun 20, 2016
Janis Putrams replied to Janis Putrams's discussion Vibration analysis
"Thanks. That's and interesting idea. I will try to do more tests.. Janis"
Jun 15, 2015
George Kelly replied to Janis Putrams's discussion Vibration analysis
"You might better-isolate vibrations caused directly by motor/prop imbalance if you flipped your stand over (motor upside-down, prop right-side-up). Like a bottom-mounted rotor on a full airframe. Or try to narrow the stand. (?) George"
Jun 12, 2015
George Kelly replied to Janis Putrams's discussion Vibration analysis
"A wild guess... Balanced prop - vibrations created by downwash striking the two ends of your stand (180 degrees apart). Analogous to those created by prop wash striking the frame arms in a full airframe. Unbalanced prop - vibrations created by…"
Jun 12, 2015
Janis Putrams replied to Janis Putrams's discussion Vibration analysis
"I changed 10x4.5 prop that was used in previous tests to CF 12x4 prop and did another test. "
Jun 12, 2015
Janis Putrams posted a discussion

Vibration analysis

Hi,My transmitter has not arrived yet so I have been trying to get deeper understanding about brushless motor and prop vibrations.I did not have any success using phone for vibration monitoring so I constructed a stand with two independent sensors:1) Analog ADXL001-70BEZ2) piezo-electric I also made optical blade sensor and counter to be able to trigger scope on full rotation.In the scope screenshotyellow - adxl001blue - piezoupper digital - optical blade sensorlower digital - upper digital…See More
Jun 12, 2015
Janis Putrams replied to Nathaniel Caner's discussion Looking for a good Android App to measuring Vibrations during motor Balancing
"I also failed to find a good Android app so I installed Python for Android and wrote a small script that does it. Though I did not have much success with balancing as I suspect the sensor is not that good for my phone. Let me know if you use it and…"
Jun 12, 2015

Profile Information

Please tell us a bit about your UAV interest
I am involved in a project developing an experimental and rather large multi-rotor flying vehicle.
I am also interested in the theory and the scientific way of research.
Hometown:
Riga

Comment Wall (4 comments)

At 12:43pm on June 20, 2016,
MR60
Forrest Frantz
said…

Janis - You are insane!  Completely off the edge of the envelope (an American expression). Absolutely loved your video. 

So what do you want to know? How can I help?

At 11:24pm on June 20, 2016, Janis Putrams said…

Great that you liked the video.

The bigger vision for me is that I think that air is very much underused. There are big planes and small copters but not much in between.
My assumption is that it is generally because of the cost of flying machines and the complexity of reliable control in the air. Electrically powered and electronically stabilized flying machines could bring the cost down to the level similarly to what Mr. Henry Ford did with automobiles.
Many refer to battery technology as the limiting factor but according to Elon Musk the evolutionary improvement in battery density is about 5% annually. In case no revolutionary technology is discovered that makes 50% improvement in 10 years. Personally I think it will be more as both EV and mobile device manufacturers are pushing very hard to improve battery capabilities.
I am currently working on a 16 propeller setup that according to my tests and calculations will be able to lift and carry about 80kg (176lbs) for 12 minutes.
What do you think about general advancement direction of short range aviation technologies? What are the greatest challenges?
Cheers,
Janis
At 2:11pm on October 12, 2016,
MR60
Forrest Frantz
said…

believe it or not, i just checked my mail.

really cool.  love the design.  Simple, light, redundant. and like the way you protected the props.  sometime i'll show everyone a simple and extremely light method of rejoining carbon tubes back into a solid piece. rejoining 15 mm tube only weighs 8 grams and produces a tube with slightly more strength that the original tube.

people would love to see a video of that puppy flying. got one yet?

on load capacity, for:

- stable hover, you need about a 25% reserve between hover thrust and max thrust (so max load = 75% max thrust)

- stable flight, you need about 35% reserve between flight and max thrust (so max load = 65% max thrust)

- stable flight in wind, you need 50% reserve (so max load = 50% thrust)

At 4:57pm on January 26, 2017,
MR60
Forrest Frantz
said…

Thanks for sharing the videos.

Fricking unreal!!!  Wish I'd seen this earlier (got too busy at the end of last year).

Looks like you got Yaw solved and the ship going and solved the problems.  Well done.

Where can you find water that isn't frozen this time of year?

So have I been so busy that I haven't shared how to join carbon tubes (let me know ... thought I did)?  And Jon figured out how to make really durable and light-weight printed motor mounts (saw that you were using Al).

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