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FeiJi's blog
Posted by FeiJi | Sep 28, 2013 @ 05:31 AM | 4,342 Views
First flight of my 9mm laminated EPP foam plank. Great carves (banks I guess), nice loops, not very good rolls (that could just be me though).. Great fun to fly. Seems pretty stall proof. Have to make a better motor mount though.
Going to make a better tail.
Sound on video breaks up a bit - I am using a cheap usb mic adapter and the driver doesn't play well with my video editing software.

Update: found out it rolls to right great but not left. Right elevon doesn't have as much throw as left so increased it a bit. Will see how it goes now.
Fixed the problem, not enough up elevon. Rolls great - fast and axial.
Ugly Plank Maiden (2 min 35 sec)

Posted by FeiJi | Sep 27, 2013 @ 04:31 AM | 4,052 Views
1 meter 9mm epp laminated foam. Wing has fiberglass fishing pole spars and is unbendable. AUW with lipo is 520 grams. Could have saved another ounce if I skipped the spars which I really didn't need. 1800kv motor with 1100mah lipo. This one is a half pound lighter than my first plank which flies really well. Will maiden in day or two. Wing is really ugly as I trimmed with knife but didn't have any sandpaper. Wing held on to fuselage with couple of zip ties. About 5 hours to build.
Did I mention that it is ugly.
Posted by FeiJi | Sep 17, 2013 @ 05:56 PM | 4,174 Views
I pulled out my Plank wing, replaced 1800kv motor with 2217 2700kv motor and 1100mah battery with 1800mah. Flew right out of my hand, very fast and smooth then started doing loops and rolls, went into death spiral and boom. Surprisingly, the wings just separated from the fuse, the motor shaft got pushed back a bit and the casing of the rx came apart but it all fits back together. Couldn't find prop or prop adapter. Crashed not far from an automobile so am thinking I need to test this out on the island where there is nothing to hit. Wow, flying it felt so smooth and effortless - and it looks cool in the air. I thought as I was walking to pick up the pieces that there wouldn't be anything left but epp just bounces. Have to rebuild this one.

Figured out why I spiraled in, left screw out of servo arm and right elevon jammed all the way up when I was slamming it around. - so my theory goes. Bent motor shaft a bit, motor probably wont last long as I will fly it anyway. Don't have any straight shafts.

Took about an hour to get plank back together. Ready to fly tomorrow.
Posted by FeiJi | Sep 05, 2013 @ 07:01 PM | 4,153 Views
My one trick pony solution.
RC Foam WIng with Elevating Motor Mount (0 min 57 sec)

Since my first flights I have had a few more and now takeoff is smoother and when I transition the motor mount to normal position and add down elevons it goes nicely into level flight. If I transition the mount without down elevon the plane will nose up and harrier until I add down elevon. The original flights were tail heavy so added more nose weight. Landings are a breeze as the wing is pretty stall proof.
Posted by FeiJi | Aug 06, 2013 @ 09:08 AM | 4,559 Views
Here is a short video of my epp finless wing prop clawing its way into the wind.
The takeoff was abysmal. The final pass is what I guess drag sounds like.
Update: I woke up this morning and just realized what is probably making the whirring noise as the wing passes downwind: I have an exposed carbon spar holding the back of the wing together - except that it is broken on one end and free to vibrate, and the wing is hollow to boot so it is probably acting like a stringed instrument. Maybe.
That might be an interesting sound effect to pursue. Like throwing a guitar out of a 20 story window.

40 inch EPP Wing in the Wind (1 min 23 sec)

Posted by FeiJi | Jul 08, 2013 @ 07:34 PM | 3,866 Views
Here is a little trainer I made for someone who has never touched a transmitter. Kind of fun.
Scratchbuilt RC Flight Trainer for Copter or Airplane (10 min 40 sec)

Posted by FeiJi | Jul 05, 2013 @ 06:20 PM | 3,518 Views
Flew at 5:00am with slight breeze - 1800mah 3s lipo and got 15.5 minute flight on my 40" scratchbuilt epp wing. Guess that is my limit as my arm is sore from holding the radio and just tired of looking up that long but happy - longest flight to date.

From 12 sheets of epp foam I now have a fast wing, a putzing about aerobatic delta wing, a 40" wing, a P51, a couple of "normal flying" 30 inch wings, a forward swept wing, a plank wing, and a few failure wings.

Sitting at about 44 hours total air time now for about two years flying. 6 more hours and I could qualify for my private pilot certificate.
Posted by FeiJi | Jun 22, 2013 @ 09:09 AM | 3,364 Views
Finally got my 40" wing flying well. A pretty good glider at around 5 WCL. Got 12 minute flight in a little wind on 1800mah 3s lipo, 1800kv motor and 7*5 prop. Moves pretty fast full throttle and floats around on 30%. Want to try 2700kv motor next.
Boneyard #5. Laminated 9mm epp foam. Had to move motor forward and still has 2 ounces of weight in nose. Should just move up to 2200mah battery.
Shouldn't have made the weird prop cutouts though, should have rounded them. Put a fiber rod to tie back ends together.
Posted by FeiJi | Jun 15, 2013 @ 10:10 PM | 3,929 Views
Here is a video showing some of my experiments with using two propellers on a single motor. My simple thrust meter uses a single prop to get about 750 grams of thrust, dual props at 0 degrees angle from each other resulted in 850 grams and dual props at 90 degrees from each other resulted in 900 grams of thrust.

Of course, using dual props results in greater current draw. But just throttled back and bit and got same flight times as single prop at full power, better flying stability in calm and windy conditions and more thrust on tap if I wanted it.

Could use a bigger prop or multiblade prop but was just interested in seeing how two propellers would play out. Now when I fly my P51 foamy I just leave both props on as there seems to be no downside.

I would like to try this on my wings but my current 3mm prop adapters are too short for two props - my P51 having a 4mm extra long adapter which had enough room for two props.

Since my P51 is a belly lander, I had to go with 0 degrees separation of the props (I tried 10 degrees separation and it broke the props on landing). I plan to get my P51 that has landing gear flying again and will try the 90 degrees separation.

RC Dual Propeller Experiment (3 min 13 sec)

Posted by FeiJi | Jun 05, 2013 @ 05:51 PM | 3,792 Views
Was flying my p51 this morning (at 4:00am) when caught video picture of mosquito and my p51. The mosquitos are really big here.

Got to change the date on my camera.
Posted by FeiJi | Jun 04, 2013 @ 09:11 PM | 2,983 Views
Flying around with the pigeons a bit. Wing flies very stable, this is now my favorite plane cause it's pretty much indestructible, won't stall, you can hand catch it, and the superman logo looks good against a blue sky.

Got my P51 flying again, new horizontal stabilizer with balsa elevator makes a lot of difference.

Just past 40 hours total air time since I started flying.

X47A Foam Delta (0 min 0 sec)

Posted by FeiJi | May 29, 2013 @ 01:49 AM | 4,590 Views
Decided to resurrect my x47a delta, and move the motor forward yet again. Flies fun now. Video just shows low level putzing around but will loop and roll nicely. Will try a little faster motor but it is nice to have a nice slow wing to play around with and not be afraid of hitting anyone. I guess this is my first real parkflyer.

Laminated 9mm epp with copyshop laminate. AUW about 450 grams. 750mm ws,
1500kv motor, 1100mAh 3s lipo, 7*6 prop, bicycle spoke control rods - heavy but never bend.
Getting 8 to 9 minute flights.

Stallproof - as video shows at end, just cut power, pull up elevator and it just floats down. Added tail because flying without it sometimes results in flat spin from rolling.

Should name it Manta as it looks more like one than an x47a - but I like the x47a shape. Would be nice to add superman logo to bottom.

X47A EPP Delta (0 min 0 sec)

Posted by FeiJi | May 17, 2013 @ 05:07 AM | 5,756 Views
Finally got my P51 flying again - it was just getting so heavy I had to move up to a 2217 950kv motor w 9" prop. Now lots of power and still get 7+ minute flights on 1800mAh battery. The motor mount is held on with hair bungees so when I have a hard landing the motor just gets pushed out of the way - less damage - as I hit stuff frequently, trees, goal posts and nets and the ground occasionally. The wing is also held on with chopstick/acrylic/bungee and is pretty damage proof. I use a chopstick through the fuselage, acrylic standoffs and hair bungees. Not pretty, but effective.
The plane is getting ridiculously heavy for a foam plane, AUW 750 grams, but it flies nicely and looks great in the air.
I am just going to have to sling it faster for takeoff.

P51 Scratchbuilt EPP with bungee motor mount (6 min 28 sec)

Posted by FeiJi | May 10, 2013 @ 03:46 AM | 2,800 Views
Just another flight of my plank, this is becoming my favorite wing as it flies so smoothly and gracefully but has nice sharp turns. Loops and rolls are nothing to brag about. Running about 80 watts per pound.

Motor is mounted with hair bungees around a chop stick embedded through the side of the fuselage. Holds motor surprisingly well and a hard landing just pushes the motor mount up but doesn't break anything.

BoneYard Plank Flight 2 (4 min 45 sec)

Posted by FeiJi | May 04, 2013 @ 10:01 AM | 2,830 Views
At least I know which one is mine.
Posted by FeiJi | May 02, 2013 @ 07:17 PM | 3,592 Views
Here is my scratchbuilt BoneYard Plank that I built last year but have replaced 1300 kv motor with 1800kv. 3s 1100 mAh lipo, 8*5 prop, prop saver, motor held on by hair bungees, AUW around 650 grams, 9mm EPP foam laminated with copy shop laminate for nice clean airflow. I build them just like the Assassin except my wings are hollow. Very little throw on elevons. CG is at about 10% of root chord. The forward half of the fuselage has an eighth inch piece of bamboo plywood embedded in the foam that I got from a clip-board, for strength.

I love flying this plane as it turns beautifully. I thought the flight time was a bit short until I saw on the video I was getting almost 6 minute flights on this old lipo at 90% throttle - not bad for me - and I hadn't even trimmed it out so think I can get longer times.

BoneYard Plank Flight (7 min 34 sec)

Posted by FeiJi | Apr 27, 2013 @ 05:46 AM | 2,723 Views
Some inane chattering while flying my latest scratchbuilt foam P51. Landed in a tree but no damage, had to climb a tree which at my age is asking for a hernia.
Fun plane now, needs some tinkering but I like it.

40 Inch Epp Foam P51 (4 min 53 sec)

Posted by FeiJi | Apr 26, 2013 @ 04:56 AM | 3,133 Views
Here is the continuing evolution of my P51 copied from the dimensions of my Tower Hobbies 40" P51. I first flew it as an elevon only plane which was interesting but rather cumbersome with slow responsiveness and an inability to loop.
Then I tried cutting the horizontal tail off and flying it which was a disaster.
Then I added the horizontal stabilizer back with elevator and after a few days of crashes and adjustments it flies. Also extended the nose by a couple of inches to counter the weight added to the tail for the elevator mods.

I now need to cut the ailerons down in size as they are way too responsive - on my radio the elevator is 100% but the ailerons are about 30% and still too touchy.
Am using an 1800kv motor, 8*5 prop, 1100 mAh battery. AUW is just under 700 grams (24 ounces). Get about 5 minute flights on this little lipo - not bad for such a heavy plane. I overbuilt it and it is pretty tough.

Foam is 9mm EPP laminated with copy shop laminate and reinforced in the nose with a couple of bamboo strips taken from a place mat and held on with hotglue and strapping tape.

The wing is held on by little hair bungees coupling bamboo strips to chop sticks poking through the fuselage reinforced by pieces of acrylic ruler.
The motor mount backing plate is held on with bungees too.
Also use a prop saver (also using hair bungees) as was tired of bending aluminum prop adapters.

Got to change date on my keychain hatcam someday.

Update Jun 8,2013: I now fly this plane on 1800 mah 3s lipo. It is auw of about 800 grams. I built a new horizontal stabilizer with a balsa elevator I found in a crashed plane. It flies great. About 8 mins on the lipo.
40 Inch Epp P51 Scratchbuilt (2 min 16 sec)

Posted by FeiJi | Apr 17, 2013 @ 04:55 AM | 2,800 Views
Here are a few takeoff, landings and flying around shots using my scratchbuilt epp p51 plane. It uses only elevons, no elevator or rudder.
Pitch is controlled with throttle and elevons. Flies like my first thrust controlled glider. Have to spiral down to land. I was happy and amazed it flew but it isn't a very sophisticated flier like my wings.
Now have hacked off horizontal stabilizer and fly it tomorrow to see if pitch control is any better - should be.

Ok, now I see why fuselaged planes have a horizontal stabilizer; absolutely no control without it - besides it looks funny.
Will add tail back with elevator and make a real plane now.

EPP P51 Elevons Only (3 min 42 sec)

Posted by FeiJi | Apr 13, 2013 @ 03:09 AM | 4,135 Views
Here is a scratchbuilt P51 made of 9mm EPP foam with airfoil wing that I am currently working on. About 6 to 7 hours to build.
Conventional wisdom says it won't fly well as an elevon plane but I want to see what the flight characteristics will be. Then will add elevator then rudder if need be.
This is just like my laminated wings, very tough material, hard to bend. I did use some bamboo spits as spars but don't think they were necessary. Double laminated fuselage and tail pieces.
AUW is 550 grams.
1800kv motor, 1100 mAh lipo, 8*5 prop.
Based it on the dimensions on my Tower Hobbies P51D, just took parts and traced onto two sheets of EPP foam. Fuselage is 3 layers thick. WIng is two layers with a 9mm foam spar in between.

Update 4:16 It Works. Flies very sedately, can do rolls but no loops. Of course I crashed, first time into a tree, shook it out of the tree and threw it back into the air. Second crash was a spiral into the ground from a right turn, not sure what led to that. Broke a prop but no airframe damage, laminated epp is tough. Wish I had prop saver for this size shaft, may have to make one.

Will fly again a few times then try taking the horizontal tail off and see if I can get it to loop. Then will add tail back with elevator..

Video of flights here:

Update 4:17 Flew a few more flights. Flies like a motor glider, can only bring it down by spiraling. Flies similar to a directional thrust glider I learned...Continue Reading