FeiJi's blog View Details
Posted by FeiJi | Feb 09, 2018 @ 07:28 PM | 7,305 Views
Here is an interesting article that says 20 degree rotor angle tilt can improve pitching movement in wind.
https://www.sciencedaily.com/release...0209100730.htm
Posted by FeiJi | Feb 07, 2018 @ 05:28 PM | 7,050 Views
Here is an interesting article showing how shark scales generate lift and perhaps this could be used in designing wing skins to generate more lift.
It would be an interesting project to 3d print a cross section mold of these vortex generators and use that to mold a foam flying wing to see how well it performs.

https://www.rdmag.com/news/2018/02/u...-wind-turbines
Posted by FeiJi | Feb 06, 2018 @ 06:53 PM | 5,871 Views
Incredible historic success.
Posted by FeiJi | Dec 18, 2017 @ 01:03 AM | 13,207 Views
Cool looking plane, hope it happens.
Posted by FeiJi | Dec 14, 2017 @ 06:29 PM | 3,582 Views
I wasn't paying attention - I guess as of December 12th, we need to register again if we fly anything over .55 pounds. If I come back to US then will have to just fly under 249 grams.
Posted by FeiJi | Dec 09, 2017 @ 05:07 AM | 3,047 Views
I can't fly 3D yet but this is a good plane to learn on without hurting anyone.

3D EPP Sumo Clone (2 min 19 sec)

Posted by FeiJi | Nov 18, 2017 @ 11:52 PM | 3,330 Views
Update: did maiden flight this morning, wow, cool. I am hooked. Flies a long time on 800mah 2s or 500mah 3s lipo. Weight with 43 gram battery is 218 grams.

I haven't done any flying or building in a long while and have never really done any 3d flying so bought this EPP kit for 15 dollars here in China that has the foam kit and hardware, I think I have everything else. It will use 2 5gram servos and one 9g. I have a couple 800mah 2S batteries but may have to buy some 3s for this one. I guess this is a Sumo clone huh?
I put the foam together with some hot glue. Will leave off the decals to save some weight.
Here is the link and couple of videos (in Chinese), the flying one is pretty entertaining.
https://item.taobao.com/item.htm?spm...cket=12#detail

I have finished adding the hardware and servos and just lacking a motor and prop now. Don't have the 1500kv motor and 8-inch prop so might just fly it as a regular airplane with at 2200kv and 6-inch prop until the suggested motor comes.
Posted by FeiJi | Aug 09, 2017 @ 11:09 PM | 3,822 Views
Here is an interesting article on how drones of the future will be powered by gas/electric generators for hours of flight rather than minutes.

https://www.rdmag.com/news/2017/08/h...ater-distances
Posted by FeiJi | Jul 04, 2017 @ 08:16 PM | 4,842 Views
Interesting article about owl wings leading edge serrations and other characteristics that make for a quieter flight.

https://www.sciencedaily.com/release...0704093621.htm
Posted by FeiJi | May 27, 2017 @ 09:37 PM | 5,801 Views
Formerly I had just taped some green LEDs onto my wing and that worked ok but you could hear the increased drag as the plane flew by and it cut down on flight time so I decided to cut some forward facing slots and insert the LED strings into the BOTTOM of the wing. Here are a couple of photos. I cut the slot, then push the wing apart and insert the string into the slot and then used a little hot glue in few places and just spread it over the slot to give it a little more strength. The LED string is flush with the wing so no increased drag.
I have done both wings and ironed on some bi-directional tape over a few areas. Hope the tape sticks.
Currently am using two small 1s lipos to power the 3 volt strings but plan on buying some 12 volt strings for the future so can just run them off the main lipo.
This should be loads better than taping on the wing. Here is an awesome writeup by CrashTestHobby.com about how to do it.
http://www.crashtesthobby.com/night-...ed-lights.html

Also an acrylic painting I did of one of my students.

Update: flew last night on football field and flies great. No drag and very visible. Unfortunately one led battery was dead so flew with only one wing visible but still easy to fly. Now can fly with or without lights and no difference in fight characteristics.
Posted by FeiJi | May 13, 2017 @ 08:16 PM | 5,821 Views
Put couple of LED one meter strings on my wing. Wow, very bright at night and dawn (totally ruins night sight). Much better than EL wire. My LED strings were 3 volt which posed a problem as I had to power them separately from my ESC battery but I had two small 1s lipos that are light and power the strings just fine. I tried using the 6 volts off the receiver but it almost killed my ESC - drew too many amps. I suppose 6 volt LEDs might work but could still draw too many amps. Other alternative is to use 12 volt LEDS and use ESC battery - probably the lightest solution and better if having more than 2 meters of LEDs.

I put the leds face down on the EPP so that they light up the wing more. Need to tape down the wires I guess for less drag. Very little weight added to the wing.

I bought my LED one meter strings (3528) for 11 rmb each (about 2 bucks) which is a whole lot cheaper than US prices that I have seen. Was worth the try. Guess I will keep them on the wing for a while and do some dawn flights since I go out running on the football field at that time anyway before the students start arriving for their runs.

Have a strange problem in that when I solder connectors to the strings and plug in the battery, only the green lights work. The red and yellow just blink on briefly and then go out. Guess the plug causes a touch too much resistance for the current my batteries are supplying (450mah). Not s
ure how I will get around this problem except with larger current batteries. Would be nice to have some other colors on the wing.

Lighting Wing with LEDs (7 min 50 sec)

Posted by FeiJi | May 02, 2017 @ 07:42 AM | 6,281 Views
Mounted my Canon 350HS Elph on my baseball cap. Much better at taking night video than my micro camera.

Lighting Dawn Flite May (4 min 18 sec)


Here is longer version of dawn flight.
Lighting Dawn Flite May 2 (8 min 47 sec)
...Continue Reading
Posted by FeiJi | Apr 30, 2017 @ 08:31 PM | 6,434 Views
A snippet of an early morning flight. Camera barely picks up the el wire lighting on the wing. Need to try leds. Will also mount my Canon Elph on my hat and try that first.
Lighting Night Flight (1 min 19 sec)

Posted by FeiJi | Apr 07, 2017 @ 04:42 AM | 6,714 Views
Saw this strange looking helicopter. The rotors are synchronized to not hit each other. Try an rc version of this.
Kmax Start and Takeoff in Agassiz BC (2 min 28 sec)

Posted by FeiJi | Apr 06, 2017 @ 06:48 AM | 6,584 Views
Added 2.3mm El wire to my Lighting. Using 12v inverter that I spliced into the 3s lipo/ESC leads and just taped it all on until I see if I like this night flying stuff. Football field is partially lit at night anyway so visibility should not be a problem. Inverter has two El wire lines out. Cost 4 dollars for the inverter and the two color el wires (1.5 meters each). I am always bragging how cheap I get stuff but that is just because I am working in China as an ESL teacher and I buy stuff off taobao.com which is really cheap here including their shipping fees (usually less than two dollars).
Inverter and El wires total 55 grams.

I flew the Lighting with the el wire and it flies nice, no noticeable drag or adverse flight characteristics and lands without dragging the el wire on the ground. But it was dawn and too light to really see the el wire so will have to get out to the field at 5:00am next time.

Update April 15: flew it this morning in the dark - easy to see and as long as I kept it in the football field it was ok but I let it get outside and lost orientation and crashed - broke wire off motor and motor mount. First time I crashed this plane. I don't really enjoy it as all I see is the lights and I don't get the feeling of flight as I can't see the plane itself. Will repair, fly once to get a video and then probably stop doing it as it isn't much fun to me. Maybe if the whole plane was lit up with leds from the inside it would be different.

Update May 1: getting...Continue Reading
Posted by FeiJi | Apr 01, 2017 @ 11:29 PM | 6,039 Views
This wing is usually flown with 2s batteries but I want to put some el wire lighting on it so need to go to 3s and I also wanted to see if battery would fit in fuselage without having to modify it. Happy to say the 3s fit perfectly since I fly with the ESC mounted on the top of the fuse for cooling. Flies pretty fast with 3s for about 5 to 6 minutes full power. Plane is a little touchier but still easy to fly. Love flying this wing - haven't crashed it yet.

Clip binder is there to attract magnets in hatch door. Could have used more magnets and may do it but the clip was handy and it is entertaining, I smile whenever I see it. Still can remove ballast coin and probably will when I add the el wire which should weigh about 85 grams with inverter.

Lighting EPP WIng with 3S Lipo (5 min 57 sec)

Posted by FeiJi | Feb 07, 2017 @ 08:56 PM | 6,655 Views
Have never really tried 3d except for a little fun with a NutBall and this balsa plane is available here in China for about $35 including electrics except battery. The nice thing is all the planes I have now use 2s and this one does too so keeps cost down. I used to use 3s up to 2200 and my wings were big and fast but now only have a football field to fly on and 800mm WS is about all I can fly here. So will order one of these soon.
Posted by FeiJi | Feb 06, 2017 @ 08:36 AM | 6,602 Views
This wing had sat on the roof of a stadium for 4 months in rain and snow and finally was blown off and I discovered it under the snow on the football field. Guess it helped that I was the only one looking for it but surprised others had not found it. Electrics still worked except for one servo. Patched it up and it flies pretty good now. Dirty but functional. 260 grams, 5 inch prop, tiny little motor, 2s 900 mah lipo. Only available in China as far as I know.

Flying Lost Wing Again (4 min 3 sec)