frederic reblewski
• Male
• Saratoga, CA
• United States

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frederic reblewski's Page

Latest Activity

"@patrick, your softwares are excellent ( I have a multi element airfoil licence that I acquired when the price was lower!) but they are beyond what an individual can afford. I understand you try to protect your revenue stream, but it would be great…"
Jul 19
"@zhanggi with a small piece of paper, high school math and physics and a pocket calculator you can compute approximates for a lot of physical data! my comment on flexibility was that your current system is about 2KW so, on one end, if the need is,…"
Jul 16
"with a back of the envelope calculation, it should use around 2 liters of gas per hour, which means that durations above 15' benefit from that approach for that configuration. the main drawback is that there is little flexibility in the power…"
Jul 15
"@Gary. is that the "wing" project you are talking about? I read some rumor but from people directly working there it is business as usual..."
Jan 12
"interesting study! I have approached the efficiency problem from the fixed wing point of view. first I came to the conclusion that the range is not the factor to optimize I prefer the range x speed. you want to fly far and fast. optimizing is always…"
Jan 12
"never is a long time, especially close to the end...;-)"
Oct 26, 2016
"@Andrew Rabbitt. I would be interested too to see your approach of the climb and glide.it seems you consider the gain comes from the better efficiency of the propeller in climb vs cruise. why would that be?"
Sep 15, 2016
"I answer to myself on flying in circle. from the picture of your flying site I see that the radius is about 600m, which means that at that speed it is about 2N centrifugal force. the average banking is then 2 degree which result in a difference in…"
Sep 14, 2016
"impressive, congratulations!! I wonder if you have compared flying in circle with a rectangular path. in theory flying in circle is a little bit less efficient as to generate the lift to offset the weight you have to either fly faster or with a…"
Sep 14, 2016
"@Damian, I do not understand. you say that the plane would fly faster that the pitchxrpm speed. I thought it was never the case and that the propeller <100% efficiency was coming from the fact that it was "slipping" and so the…"
Sep 11, 2016
"as for the 3S vs 6S, I think the only real advantage is to lower resistive loss. very rough evaluation:  if during cruise you are @ 100w and your total resistive path ( batteries, contacts, cables, on resistance of the Fets, motor ) is 0.1 Ohm…"
Sep 10, 2016
"@ Damian, I am curious. where does the 70W come from?with 20AH and 3S you have around 800KJ. the flight being 100min that's about 130W average power? if your assumption is true on the L/D ratio the mechanical power needed is DxV so around 33W…"
Sep 10, 2016
"why not? more complex more expensive  heavier less reliable less energy efficient drive system from a central engine = lots of destructive vibrations ... in fact one could claim that the only multicopter advantage is mechanical simplicity…"
Mar 31, 2016
"does it mean that normal RC airplanes will be now limited <50m altitude? that would be the end on the hobby. try to do a loop with a 2.5m wingspan airplane and stay under 50m or fly a sailplane under 50m...nonsense... if the next slice…"
Oct 18, 2015
"looking at the spreadsheet the overall drag is just the zero lift drag ( considering that it is a coefficient for the full airframe with the wing area as a reference area?? ) plus the induced drag. I do not know how the zero lift coefficient is…"
Oct 10, 2015
"@jerry I dont get your comment about efficiency?? the 40% is supposed to be what is left in mechanical energy from the electric energy straight out of the battery: battery restitution, cables, ESC, motor, propeller represent 60% loss"
Oct 10, 2015

Profile Information

engineer with interest in anything that flies.
mainly interested in airframes and the "system" aspect of UAS with an emphasis on efficiency. more interested in data than what is "cool"
Hometown:
originally from Paris, France

Frederic reblewski's Blog

3D printed brushless gimbal for GoPro

Posted on June 29, 2013 at 7:00pm

I am a member of a French yahoo group on 3D printing. Today a member posted a link to this nice brushless gimbal that he designed for the GoPro hero3 and posted on Thingiverse. he did not reference the controller he is using but he published the design files …

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Small UAV Design and Application talk at Carnegie Mellon's Silicon Valley campus

Posted on March 28, 2011 at 3:30pm

for those in the bay area:

Thursday April 14, 2011

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Comment Wall (1 comment)

At 12:26pm on July 22, 2011, George Tarrant said…

Frederick

I do plan to write up my method for PID tuning but other commitments mean it may not be anytime soon.

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Season Two of the Trust Time Trial (T3) Contest
A list of all T3 contests is here. The current round, the Vertical Horizontal one, is here