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Flying wing as a beginner plane?

nxc

Junior Member
#1
Flying wing as a beginner plane? (Now a build log)

Hi there!

I was wondering if a flying wing, such as the Versa Wing, would make a suitable first plane for a fixed wing newbie? The reason I ask is because it is easier and cheaper for me to get hold of 50mm sheets of EPS than it is to get foam-board, so I can happily cut some wings to learn on. The cost of shipping speed build kits to the UK is also pretty prohibitive for me.

I'm not concerned about the build process as I love building things from scratch and figuring out how to make them work; rather I'd like to know if it is complete folly for me to start with a wing. I've been watching the Beginner Series and they mention starting with wings as a reasonable idea at least once, but I wanted to double check here before I start building.

I have a radio (FlySky FS-TH9X) and experience with the electronics as I've built (and am having great fun learning to fly) a tricopter. I'm also spending some time flying wings on a simulator to get an idea of what to expect when I get out in the real world.

Finally, what can I expect from wings flying in windy conditions? Unfortunately Scotland doesn't always offer the most favourable flying conditions so I'd like to get started with something that will be a bit more forgiving in the wind if at all possible.

Thanks,
nxc
 
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eagle4

New member
#2
hey nxc, welcome to the forum.
flying wings are ok, but honestly as a beginner plane i'd definately suggest a plane that has dihedral, as dihedral helps the plane self level if you get into a bank, as a beginner you'll find this quite handy. also launching a flying wing is tricky, well i find it tricky at least anyway, if you got a beginner plane like the FT flyer then you'll find launching it is easy, its as easy as throwing a tennis ball. flying wings are great, but i'd be hesitant to suggest it for a beginner.

although, as you can get foam at a reasonable price, i'd suggest go for it mate. its a pusher, so your motor and prop will be safe if you crash it, most of your electronics will be the same. the biggest thing to keep in mind with a flying wing is your CG. this cannot be stressed enough. if its even slightly back from where its ment to be then your plane will be almost completely unflyable. and thats by someone who isnt a beginner.
 

Tritium

Amateur Extra Class K5TWM
#3
Any plane can be a beginner plane. Some styles just last longer without crashing! ;)

Seriously though, A High Wing Plane such as a Piper Cub is a great first plane. Low wings are more difficult to fly and ALL "Wing" Planes are VERY touchy about balance around the Center of Gravity.

Welcome to the forum.

Thurmond
 
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jetpackninja

More combat please...
Mentor
#4
One of the big challenges with learning to fly wings is orientation. Stick time on a sim, even a free or a cheap one can be a big help.
Play around with the wind settings and with the markings if your sim is customizable. I have one of the wings just left pain white and fly it far away to learn to figure out it's orientation and learn to watch it react.

Agree with everyone else here and I usually recommend a wing as a good second plane, after some time with a slow flying trainer.

Most wings can be quite fast, setup and launching can be daunting for a newbie. What kind of support do you have? If you have a friend that can help get your wing setup and help with the first few launches it can really help. For a first wing, I prefer EPP. A good EPP plane (like the CTH Assassin) is strong enough to survive your learning curve.

Wings in general handle wind very well.
 

pgerts

Old age member
Mentor
#5
Scottland (many places) is great for slope flying and wings are great on the slope.
If you are cutting wings from solid EPS - do not forget to put in some kind of wing spar and to cover the wing to get it strong.
Take a look att a PSS site to get inspiration - "all" planes are cut from EPS.
 

nxc

Junior Member
#6
Thanks for the feedback everyone!

I've done a quick bit of googling and it looks like there is a calculator I can use to find the CG once I have the dimensions. Do you guys know if that tool is reliable? I saw someone recommend starting a bit forward of the CG and then moving back until it flies a bit high-alpha then moving it forward just a touch to get it right. I have definitly heard the Flite Test crew say "A nose heavy plane flies badly, a tail heavy plane flies once" so that advice seems sound.

I guess that all the electronics need to be positioned to maintain that CG, is that the case? Would it be reasonable to base my design on the Versa wing and hope that the recommended electronics for that work out for my wing?

I have a few friends who would be willing to help out with the launching for the first couple of flights, but no-one who knows any more than I do about this kind of thing (which is what makes this community so valuable!).

pgerts, those planes look amazing, but well beyond my flying ability for now ;) I was actually inspired by IBCrazy's Specter v2 - I love the look of the forward swept wings. The only reason I'm not building something like that straight away is because it is 4 channels rather than 3 (which almost seems silly now - I could always ignore the yaw until I'm ready). I was planning on getting some 900 *10 * 12mm pine spars (these are about 80p from the local hardware shop) and some sort of laminating film I can apply to strengthen the wing.
 

earthsciteach

Moderator
Moderator
#7
I have used that calculator for several flying wings that I've scratch-built. It works well. I usually use 20% CG. The cg on my fpv flying wing turned out to be a bit forward of where the calculator stated, but I think that was using the "extended" version of the calculator.
 
#8
NXC, a flying wing isn't a bad idea for you first plane so long as you are fully aware of what that will mean for you. I got into the hobby with Flite Test as my only ally and was able to accomplish successful flights with a modified versa wing and you sound a bit more experienced than I because of your familiarity with Tri-copters. For some reason I hated the idea of using rudder/dihedral for turning and was fixated on the flying wing using elevons for bank and yank. I have since built a FT Flyer for 2 reasons. 1. Space and speed, I live in a city and there are only 2 reasonable destinations that I can fly the versa safely. I found that the versa requires about 2 full length soccer fields at minimum to be safe. The FT Flyer on the other hand needs about 25% of that space. 2. Simplicity, now I hope for the best but expect the worst and I knew that eventually I was going to crash really hard and be out of commission for a while so I figured the swappable pod might save me some headache when rebuilding. You are right about the wind, my modified versa can take twice the wind-speed and gust. About 10mph constant and 16mph gust is usually my limit skill wise with the versa.

All and all, its probably a good idea for you to start with a wing. Just be careful with your CG take time to set up your Tx with dual rates and Expos. Those 2 elements made all the difference for me.
 
#10
I agree with the rest. It's up to you if you want to start with a wing plane.. but my personal opinion will be a FT Flyer for a first plane. Like you said its windy and the FT Flyer likes a bit of wind. :) You will land the FT flyer like a chopper in the wind. Awesome plane to start with. When you get some stick time on the plane then you can start doing more fun stuff..like loops.

The Calculator for CG works just fine. I have used it on 3 of my planes..and also start at 20% CG

But it's up to you.. I started flying on a low wing plane... Learning curve.. He He

Most important thing is that you must have fun

Happy flying
 
#11
Hi there!

Finally, what can I expect from wings flying in windy conditions? Unfortunately Scotland doesn't always offer the most favourable flying conditions so I'd like to get started with something that will be a bit more forgiving in the wind if at all possible.

Thanks,
nxc
Id say if you can fly a tricopter you are hardly a beginner ;)

Id recommend a Parkzone T28 with 2200mah bat & HKing G10 motor for wind. It should also be OK for your skills as its very easy to fly & quite tough, & spare parts are easy to get. In wind it really needs the bigger motor.

Its been very windy down in New Zealand the last 3 months (& the last 2 years) . My best planes in the wind are
Parkzone T28 with upgraded G10 motor , hardly notices wind at all. Alot of fun to fly .
Lanyu P47 : this is a very cheap & nasty R2F, basicly poorly made junk thats excellent in wind (but shouldnt be)

My 2 'wings', Teksumo(popwing) & PZ striker are OK in wind but not as good as the T28 or P47 I have.
The wings can be a handfull in the wind , the teksumo is almost unbreakable with a few simple mods.
Im not sure why flying wings got such a good rep for flying in wind...
 

nxc

Junior Member
#13
Hey guys,
sorry it has taken me so long to get back to you all! This weekend I finally managed to get my wing cut:
W8JmCwL.jpg

I started by trying to cut the wings using a hot wire on a pivot with a template at just one end, but ended up with a stack of foam shapes that I wasn't happy with because either the wire was too hot or tip profile wasn't to my liking. In the end I cut a set of templates for each end of my wing and used the negatives of each template to make sure they were positioned correctly relative to each other. Then I just went to town carving the foam off the top until I was happy with the result. I found this sooo much easier than not knowing exactly what I was getting until I'd traced the whole template with my hot wire on a pivot.

9m2a4HE.jpg

In the image above you can see my Super Safe™ hot wire cutter. It really is just a transformer with a dimmer switch and LED to show whether it is on or not. Don't try this at home kids...

This is the first wing I cut. I'm very happy with the result after all my disasters with the pivot. Hopefully a little bit of sanding will sort out the lines:
JZlcPH6.jpg

qZQYkMT.jpg

As you can see with a bit of practice you can get some really nice cuts this way.

So, on to my next questions! I was quite surprised that this method of cutting worked so well, and hadn't really planned much further ahead. I have some electronics, but I'm not sure whether they will be powerful enough. When I was looking at the electronics I was in two minds whether to get a TBS Caipirinha or not, so I took a look at the recommended kit on there and bought something similar. I have:
  • Turnigy SK3 2822 1740kv motor;
  • Turnigy Plush 12Amp ESC;
  • 2 Cell nano-tech 3300mAh battery.
I've also got some 8x6 and 8x5 props, a pair of 9 gram servos and my receiver. Any idea whether this lot will work? I'm quite happy to find out the hard way - I'm going to try it all anyway for the hell of it because the foam is going to get broken one way or the other... My biggest issue is whether I'm going to fry my ESC, it looks <swedish>tiiiiiny</swedish> compared to my ESCs on my tricopter but then they are rated for 30 amps.

Secondly, I'm starting to think about how I'm going to mount my motor. I'm using an MH-61 airfoil which seems to have some very good flight characteristics at an attack angle of nine degrees. So should I think about mounting my motor at nine degrees from my chord line? Mocking this up on CAD software made we start to think about my CoG (97.31mm back according to both the calculators, thanks :) ). Now from playing around in Kerbal Space Program I know that if my thrust vector isn't lined up correctly my plane is going to flip its self over on the way up to space. Do I need to think about lining the thrust vector up with my center of gravity, or my center of lift? If it's my center of lift, does anyone have any bright ideas for calculating that on my swept wing? A quarter of the chord length isn't going to work for my tapering, non symmetrical airfoil.

Sorry for the slightly rambling end to my post, I've had this stuff bashing around inside my head all weekend.

Edit: so I just came across this:
The angle of thrust, or motor angle, needs to be through the center of lift, not necessarily the center of gravity (on most decent flying planes, they will be fairly close together anyway).
Can I aim my thrust vector through the center of gravity and expect reasonable results? Also, when you are calculating the CG position you have options for 15%, 20% etc. What does this mean? Is it some distance in front of the center of lift? That would be my guess, if I wanted a plane that pitches forward when it stalls.

Thinking about airplane design is fun!
 
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xuzme720

Dedicated foam bender
Mentor
#14
To answer your first question, yes. Since the center of gravity and the center of lift should be very close on a wing(no other lift generating surfaces) the CG and CoL will be almost interchangeable.

When cg is given in percentages, it is usually talking about a percent of the MAC or mean aerodynamic chord. So, 15% on a 20cm wing is going to be 30mm back from the leading edge and so forth. On a tapered wing it needs to be measured at the MAC though...
GMC.jpg

More on finding safe initial CG's can be found here: http://www.theampeer.org/cg/cg.html
 

ofiesens2

Professional noob
#17
I believe that the simplest way to find CG is to just guess it, chuck it without power and neutral control surfaces, and adjust it to make it better. Or: Guess, chuck, adjust, repeat. And this is for getting it close, not fine tuning.
 

nxc

Junior Member
#19
Cheers FlyingMonkey.

I went to get my motor mount and ailevons (I think that's what they're called on a flying wing) cut, but sadly the laser was all booked up today. I was especially gutted because I got into bed late last night and realised I made a mistake on my motor mount. An hour and a half of lying there thinking about it I decided there was nothing for it but to get up and fix it. So after a week on holiday I went to work with only 5 hours sleep. Hopefully I'll get them cut tomorrow.
 

nxc

Junior Member
#20
So after a bit of a palava with machine bookings and file formats, I managed to get my parts cut. I designed a motor mount which should give the wing an angle of attack of 9 degrees, hopefully through the center of lift. The little Playmobil police-pilot is holding up the motor because otherwise the whole lot just tips up in the air.

wcjuTju.jpg
jb7d0uG.jpg

I also cut my ailevons giving myself clearance for up to an 8" prop. I used double thickness for the first half of the control surface to help maintain the airfoil shape. I've actually cut the last 5 cm off the MH-61 airfoil because it would have been too thin to cut and flimsy for attaching control surfaces to. A bit of static reflex should help maintain the original aerodynamic properties.

8bFe8b8.jpg
kQk9w0Q.jpg

All the parts are cut from 3/32" basswood (~2.34 mm) using a laser cutter at a wonderful digital fabrication studio here in Glasgow. It actually cost me less to get it cut than the material its self. I had planned to use balsa wood, but this stuff was available at the shop and seemed more rigid and less foamy.

Whilst thinking about how I'm going to strengthen and cover my wing I shelled out for a whole months subscription to eCalc. What a wonderful tool! It looks like I might be a bit thin on power, but I guess this will be my first plane so I don't need anything beefy. Still, it looks like I'm cutting it a bit fine.

With my 8x4 prop I need to keep the weight of the actual wing (not including the power plant) under 140g to maintain a thrust to weight ratio of 0.8:1, or a power to weight ratio of 151W/kg (69W/lb). From the Easy 3D podcast, I think I heard you want 100W/lb for a normal flyer and 70W/lb for a trainer. So one option is to get a bigger prop. I have some 8x6 props, but according to eCalc that will a) draw more current than my ESC can provide; and b) "The airflow at the propeller blade will stall. Therefore the static thrust and max. current may not be reached. On ground you will measure *Stall Thrust* as maximum." I'm not sure what that really means but its in red so it's probably bad.

It looks like the best option for me is to get some 8x4.7 props and keep the wing as light as possible. As it currently stands my weight without the power plant is ~120g. But I still need to add a covering and vertical stabilizers. Is it worth going for something like Solarfilm Solite, which 18-20 g/m[SUP]2[/SUP]? I was thinking about using duck tape, but that seems like it is going to be too heavy now.

I also see a lot of wings without vertical stabilizers, is it worth keeping them whilst I learn to fly? Or is it worth ditching them so I have something that does fly?

I guess I need to get on the simulator again, I could have something that flies soon...