Mini Fun Jet build

[Hell2Go]

I designed a flying wing at 30inches then did one at 20 in and another at 45 inches to compare the flight characteristics of each.

the 20 inch was wicked to fly, and cg was really touchy. it reacted faster than I could so I put it into the ground a lot. my son could handle it though.

the 45 inch needed a huge motor for the performance that I expect out of my planes, used a 4240-1300kv with a 10x7 with a 3s 2200mah. it had unlimited vertical and could see it well anywhere on the field but rolls were a little slow and my servos were underpowered causing random reactions under high stress situations. it had great gliding abilities. might upgrade to larger stronger servos an it would be a fine flyer. top speed was limited to around 65mph due to a thick highlift airfoil.

the 30 inch is more or less perfect! it supports a wide range of common motor sizes from a 24g blue wonder for nice gentle performance with a small 3s, to sky tearing flaming performance with a 2826-2200kv with a 5x5 and a 1300mah 4s with a thinner airfoil will put the wing into th 80 to 90 mph range. with a thicker airfoil it is limited to about 80mph but still has good low speed qualities too.

the 30 inch was my favorite and is still my goto plane. at the moment it has that little red motor that is so cheap http://www.hobbyking.com/hobbyking/...ner_1200kv_USA_warehouse_.html?strSearch=2822
using an 8x6 with the 1300mah 4s im getting about 70 mph and 8-10 min flightimes and a lot of fun.

I need to do a build log and article on the 30in wing as it is a quick easy build, cheap and massive fun. I can build one in a day and be flying before dark.

actually my avatar is my son's 30in and my 45in. my son is 11 and that was his first build and it flys better than mine! he likes to show off by putt-putt-putting by at about 5mph on the first low flyby for someone watching him for the first time, and they go "ooh aah!" then on the next pass he will rip past at about 80mph and they say "OH MY GOD!" then he'll do another pass blistering by inverted 3ft off the ground then as he passes goes vertical into a rolling climb till it is literally out of sight, then they say" HOLY SH*T!! That boy can fly!!!" then he just smiles that little smile that shows that he is proud of himself.

 

[ttprigg]

Hello-
I wanted to offer something to this thread and the community. When I saw KLP72's article, I was really intrigued and I took a stab at creating plans based on his sketch. Love the way everything fits together. The entire wing can be cut from a sheet of DTFB. I have built it off these plans but I have not flown it yet. (Maybe later today )
I see that Hell2Go has enlarged the wingspan, and it sounds like that scale may me more in "My Flight Envelope"... I'm going to try some lower power set ups and see how it goes.
Anyway, there are 2 sheets of plans- I tiled them for folks who do not have access to large format printers. I hope these plans help-- Let me know if you see something that needs to be adjusted.

 

[JohnRambozo]

I designed a flying wing at 30inches then did one at 20 in and another at 45 inches to compare the flight characteristics of each.

the 20 inch was wicked to fly, and cg was really touchy. it reacted faster than I could so I put it into the ground a lot. my son could handle it though.

the 45 inch needed a huge motor for the performance that I expect out of my planes, used a 4240-1300kv with a 10x7 with a 3s 2200mah. it had unlimited vertical and could see it well anywhere on the field but rolls were a little slow and my servos were underpowered causing random reactions under high stress situations. it had great gliding abilities. might upgrade to larger stronger servos an it would be a fine flyer. top speed was limited to around 65mph due to a thick highlift airfoil.

the 30 inch is more or less perfect! it supports a wide range of common motor sizes from a 24g blue wonder for nice gentle performance with a small 3s, to sky tearing flaming performance with a 2826-2200kv with a 5x5 and a 1300mah 4s with a thinner airfoil will put the wing into th 80 to 90 mph range. with a thicker airfoil it is limited to about 80mph but still has good low speed qualities too.

the 30 inch was my favorite and is still my goto plane. at the moment it has that little red motor that is so cheap http://www.hobbyking.com/hobbyking/...ner_1200kv_USA_warehouse_.html?strSearch=2822
using an 8x6 with the 1300mah 4s im getting about 70 mph and 8-10 min flightimes and a lot of fun.

I need to do a build log and article on the 30in wing as it is a quick easy build, cheap and massive fun. I can build one in a day and be flying before dark.

actually my avatar is my son's 30in and my 45in. my son is 11 and that was his first build and it flys better than mine! he likes to show off by putt-putt-putting by at about 5mph on the first low flyby for someone watching him for the first time, and they go "ooh aah!" then on the next pass he will rip past at about 80mph and they say "OH MY GOD!" then he'll do another pass blistering by inverted 3ft off the ground then as he passes goes vertical into a rolling climb till it is literally out of sight, then they say" HOLY SH*T!! That boy can fly!!!" then he just smiles that little smile that shows that he is proud of himself.

That's awesome. Do I detect a bit of fatherly pride? (and rightly so!)

That's $6 motor sounds pretty nice, too.

 

[Hell2Go]

I find you get what you pay for with motors... the setscrew on the red motor comes loose and the motor spins or pops out and twists the wires all up and they usually break a wire in the windings, so... I now have experience with rewinding motors. IF you use one of this type motor with a similar motor mount, drill and tap for a second setscrew 90deg from the first one and use locktight!

I've been turned onto sunnysky motors and DYS motors from http://www.banggood.com/buy/SunnySky-Brushless-Motor.html they are high quality motors with Japanese bearings and beastly for their size. they cost a little more but its also free shipping. I've done a lot of research on the cheap motors and these two are the best bang for the buck.

 

[Hell2Go]

The plans I posted so far are to the dimension given by Kevin in the Flitetest Article. I haven't scaled it up yet but plan to in the near future. the 24g blue wonder or hextronik 24gram motor should do fine on this plane, just use a 7x4 is prop to keep the performance manageable or an 8x4 for a little more thrust of a 7x6 for more speed, just check the motor temp after about 30 seconds of full throttle to make sure it don't get to hot... if you can't hold it, its too hot! that's with the 1300 or 1500kv motors, the 1700kv, I haven't tested for propsize, but I would say 7x4 would be max for 1700kv.

 

[Hell2Go]

I blocksand curved matching parts together to get rid of bumps.



forget that little square on the bottom piece, but leave the paper long to wrap around.




All the parts awaiting assembly...




Peel the paper on the inside of the top and bottom pieces or it won't bend. Light amount of glue an keep it square, attaching sides to flat bottom first.




after it cools a little glue the curved part of the bottom and roll it on the table to close up the gap.




start with just the flap at the nose and make sure it is straight with a test roll, you might have to spread the sides a little.




just glue 1/4 to 1/3 of the way at a time




when you get to the end, don't push too hard or you'll get a crinkle like I did. I glued some scrap pieces inside behind the crinkle to strengthen it. trim the foam even with the end keeping bottom paper to wrap around the end




cut a scrap to put inside before you wrap the end to keep it neat.

 

[Hell2Go]

Had to trim out some foam for the wing mount tongue depressor. I didn't think ahead here, I should have shimmed up the tongue depressor with 2 thicknesses of foam, but I already glued it in place too well.


If you do the foam, peel the paper and make it the same width as the tongue depressor.

 

[Hell2Go]

I trim the squeeze out glue with scissors on a 45deg angle, this cleans up the rough edges of the paper too.




Still not perfect, yet...




A little smoothing with my antique monokote iron.




Now its smooth and nice!

 

[Hell2Go]

I sharpen the trailing edges with my iron.




I keep the topside flat so it looks good, don't know how it might effect flight performance though...





I round over the leading edges and this helps to keep the paper on better.















I try to round all the edges to keep paper on.





Don't forget this edge, it would peel too given the chance.

 

[Hell2Go]

all assembled and waiting for electronics!

 

[JohnRambozo]

Wow. It looks so cool and compact. Get those electronics in there.

 

[kpl72]

It's pretty cool to see what you've done with the design!

Awesome Job on the build! That is amazing. I like how you ironed the edges. I saturated with glue, but that probably added a lot of unnecessary weight.

As for the speed thing, I was actually hoping this would be a fun, easy, close in thing, not too fast, but fun. I really like the FT22, but wanted something with more axial roll and just a little smoother flight characteristics... No idea if I've hit it yet.

I love the idea of a 150 or 200% version. Would be a blast.

I'm also thinking about interchangeable noses to put the mobius up front.

Hell2Go - what are you thinking about for paint scheme? At one point I considered making the nose a little different and trying to squeak out a Disney Planes F18 scheme.

 

[Hell2Go]

Well, my son kinda confiscated this one on me... He wants it uncoated white with a couple stripes to "differentiate orientation" ( his words) to keep it light as possible. He likes the smaller planes, so I said ok, I'll do the bigger one for me. I'm planning on a poor man's fiberglass job on mine, maybe go for a Blue Angels paint scheme with a yellow bottom for visibility. I've been thinking about a funjet type plane for about a year, that I could glass and see how that works. I'll probly do a build thread and maybe an article on the glassing if it works out well.

I like the Idea of the interchangeable nose for a camera or FPV options, probly work better on a larger platform to handle the extra weight.

I do like the blue and yellow on your original, if the boy will let me paint his, I might do that in honor of your design.

 

[Hell2Go]

I can't recall if I mentioned it, I really like the way the nose slides on to hold the wing... really convenient, is that something you came up with or something you saw somewhere? its brilliant really...

 

[kpl72]

The nose thing just kinda happened. I had built the mini guinea the week before and I liked the slide on nose for getting to the battery, since hatches can be an issue on these designs. I also like being able to replace the nose, not the entire fuse. When I drew the contour, I liked how it went over the wing, hiding the boxyness. It was at that point, I was like COOL - this also solves how to hold the wing on. A glued on wing is a lot less crash tolerant. THen I figured I just needed a tab, somewhat the opposite of the FT swappable designs for holding in the motor. I find new ideas very rarely come out of the blue, but are achieved by applying exisitng solutions in a slight different way...

Let me know how your son likes it. I really hope it flies well for you.

Kevin

 

[Hell2Go]

"Necessity is the mother of all invention"... me

 

[Hell2Go]

Well, I used black packing tape on the fuse to protect from damp grassy landings.


Added taileron servos and motor mount for my 24g blue wonder that I rewound.


Don't know what I was thinking, should have cut the servos into the fuse!


Servo linkage and control horn in place.


Checking horn size, ( just right ).


Laying out horn placement.


Ready for the motor, had to extend the motor leads so they reach the fuse opening to make it easier to plug into the ESC.


A little red on the top to help with orientation.


Yellow on the bottom like most of our planes for its high visibility in the air.


That would be an APC 7x6 prop... with a 4s and my rewind on that motor, I would guess that I should get about 80mph out of this plane.


Just waiting for my new receiver and she'll be ready for the maiden!


I did some testing and weighing and here is what I came up with:

AUW with 3s 1000mah came in at exactly 400g.

Motor testing results:

6x4 APC style produced about 450g of thrust.
7x6 APC style produced 545g of thrust.

So... with an extra 145g of thrust over weight ratio, I think it should have decent vertical performance!

If that's not enough performance for my son, I have a 2826-2200kv screamer and a 1300mah 4s that should make this thing go hypersonic!! With the right prop it could see well over a hundred + mph!

I CAN NOT WAIT!!!!!!!!!!!!!!

 

[JohnRambozo]

Motor testing results:

6x4 APC style produced about 450g of thrust.
7x6 APC style produced 545g of thrust.

So... with an extra 145g of thrust over weight ratio, I think it should have decent vertical performance!

If that's not enough performance for my son, I have a 2826-2200kv screamer and a 1300mah 4s that should make this thing go hypersonic!! With the right prop it could see well over a hundred + mph!

I CAN NOT WAIT!!!!!!!!!!!!!!

The roll rate on that thing is going to be insane.

 

[kpl72]

Time for a designer's disclaimer?

That would be an APC 7x6 prop... with a 4s and my rewind on that motor, I would guess that I should get about 80mph out of this plane.

YIKES! That'll thing will scream... Watch the torque roll on launch, make sure you have positive airspeed before you give the full guns...

 

[kpl72]

Needs Down Thrust

Okay, so I tried flying it today. I need to add in a few degrees of down thrust. It glides well enough, but when I add throttle, it pushes the nose up and then it just wallows, eventually tipstalling and spinning....Good news - the design is pretty rugged. I'm going to shim the mount to add in a few degrees of down and see if that helps....Kinda bummed, but I guess that's the design process...

Kevin