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Old Jul 24, 2010, 04:56 PM
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Canada, QC, Montreal
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Ritewing UAV - 60" Blunt Nose Zephyr

After a few months of letting it sit in the box waiting patiently, I have finally started work on my Ritewing UAV - a 60" blunt-nose Zephyr. It is being built as part of a university project to build a UAV for a competition here in Canada. This wing will be a test-bed for our autopilot and camera systems, so it won't be a speed demon, but will have lots of wing area to carry all the stuff we need it to. Plus it is going to see lots of abuse as we tune our autopilot, so the durable EPP will be nice.

Some details:

The span is 60" (5 ft) - it is a 54" Zephyr with a 6" extension in the center (thanks CK for hooking me up with this).

Powerplant is a Turnigy C3548 1100kV motor with a 60A Plush ESC. Current prop is a 12X6, which should give lots of thrust for lifting heavier cameras with decent speed if we need it. I plan to use two 3000mah 3s packs.

I have marked out the bays for all the equipment. Batteries are going on the sides in the angled bays to keep them well forward, but out of the way to that the camera can be centred and as far forward as possible. There is also room in these bays for the Xbee modem (telemetry) to be mounted on one side, and the video Tx is to be put in the other side. This keeps them as far apart as possible, without having to run wires all the way out to the wing tips. If there is too much interference, I'll move them to the wing tips.

The forward center bay will have a completely removable hatch so that a pan/tilt rig can be mounted. I will likely install some sort of mounting plate or rails into this bay for easy removal of the camera. There should also be room for a small battery for the video system. This can also serve as a place to store additional batteries or ballast if there is no camera onboard.

The second bay will hold the autopilot (Paparazzi) and the receiver/PPM encoder. I haven't decided where to put the IR sensors yet, but I will probably make a small mount for them and attach it to the top of the wing. They are very small and light, so placement isn't a big deal in terms of weight and balance.

The third bay is for the ESC. I may add an air intake in this hatch for cooling, and direct airflow to the motor as well. I won't be pushing this wing too hard, so I don't expect cooling to be a major issue. I suppose I could just combine the second and third bay into one, but that might decrease the strength too much in the center.

The kit came with another 4" center section that I decided not to use, since I think the single 6" section should give sufficient room for everything. But the more I think about it, I am wondering if I should use it and make it 64" total....hmmm. Anyway, I marked off the shape of the current leading edge onto the side of the extra piece so that I can add an extention to the nose later if I want.

There are two main spars that run through the wing. I had initially intended on having the wings removable, but decided that it was easier to just make it one piece to give it better strength, and so I didn't have to come up with a way of securing the wings to the center section. I had an old carbon fiber arrow shaft laying around than fits nicely over the full length carbon tubes. I'll add this to the center section on one of the spars for added strength.

In addition to the main spars, the kit came with four fiberglass rods. I will put one along the top and bottom of each wing, as close to the thickest part of the wing as I can for maximum stiffness. Since I'm cutting a lot of bays into the upper surface, I'll add some carbon rod and strip between each of the bay to keep things a bit stronger. It might all be overkill, but better safe than sorry I guess.

I made a spreadsheet to track the weight of all the components and to find out where the CG is. Based on what I calculated, the CG should be around 8-8.5" from the leading edge. I'm aiming for 8" to be safe. My spreadsheet puts me right around that mark, so I'm happy. Once the auto-stabilization is tuned, it should be okay with a more aft CG.

The kit came with some yellow mesh stuff, which I am assuming is the reinforcement fabric? Its all in one piece, which looks like it might be a bit awkward to work with, so I'll probably cut it into strips to make things a bit easier on myself. I'll then cover with some monokote (which I have never done, and should turn out pretty terrible).

With a 12" prop, the prop cutout is going to be pretty big, but I hope this won't be too much of a problem.I notices that with the included motor mount, only two of the holes on the motor line up with those on the mount, so the motor can only be attached with two screws. Is this okay?

I also found that the holes on the motor mount and the mounting plate don't line up. I guess I need to drill holes in the plate to get them to match up? Or am I missing something here??

This is my first Ritewing Build, so any tips/advice are welcome. I've watched the DVD, read lots of threads, etc, so I hope I don't make a complete mess of things...
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Old Jul 24, 2010, 05:06 PM
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Hey buddy ,looks great, I would suggest a modified folding prop setup, the first time that prop catches on landing it might rip the motor out and tear things up.


ck
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Last edited by klique; Jul 25, 2010 at 03:47 PM.
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Old Jul 24, 2010, 05:31 PM
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Thanks. Good point on the folding prop, I'll check it out. That 12" prop kind of scares me. Its a big area to avoid while hand launching and can probably do some serious damage.
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Old Jul 24, 2010, 07:23 PM
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There's too many "standards" for mounting holes, so I'm not surprised they didn't line up. I'd just drill new ones.

I've always been amazed that people dare to launch wings in the traditional way, especially the really fast ones with tiny and dangerous props.
I have been using this launching technique on 48" wings, and it works well:

How to launch a flying wing safely (0 min 21 sec)
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Old Jul 25, 2010, 11:35 PM
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aero k
Your design has caught my eye!
Impressive indeed.
Would you kindly share the build plans with me. I am also planning to make a UAV out of the flying wing. I have some EPP lying at home and would want to cut the wing profile with a hot wire????? How did you carve out the wing profiles?
Any reason you did not want a fuselage?
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Old Jul 26, 2010, 10:41 AM
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Originally Posted by jawadmalik View Post
aero k
Your design has caught my eye!
Impressive indeed.
Would you kindly share the build plans with me. I am also planning to make a UAV out of the flying wing. I have some EPP lying at home and would want to cut the wing profile with a hot wire????? How did you carve out the wing profiles?
Any reason you did not want a fuselage?
The wing cores are from Ritewing RC. Talk to "klique" here on RCgroups about either buying a kit or about profiles.

I guess you could consider the center section as the "fuselage", since it holds most of the equipment. It is much more efficient than a traditional fuselage, since there is less drag and controbutes to lift.

Update:
Everything has been glues together and reinforcement spars have been added. I also drilled new holes in the plate for the motor mount. I tried to use hot glue for joining the wing halves, since it's always worked great on my EPP Superflys, but I just made a mess of it. The glue started to harden before I could get the spar inserted and it left a small gap between the wing and the center section. I ended up having to cut out the hard hot glue and used white gorilla glue instead. It was a mess, but I managed to get it together okay. I know, I know, I should have used 3M90 like I was told...I'm stubborn that way.

It was a bit of a challenge lining up the three sections, since the center has a slightly different airfoil than the wings. Plus, there is no wing bed for the center piece, so I had to resort to the TLAR method for getting it lined up.
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Old Jul 26, 2010, 11:01 AM
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Yep 3 m90,lol some people will never listen
Gorilla makes it a pain to cut the bays due to its hardness and density in,it slows down the cutter and it makes for messy bay cuts.
3 m 90 gives you the time to align the pieces and you can cut through it like butter ,it makes for great bay cuts.

Quote:
Originally Posted by aero_k View Post
The wing cores are from Ritewing RC. Talk to "klique" here on RCgroups about either buying a kit or about profiles.

I guess you could consider the center section as the "fuselage", since it holds most of the equipment. It is much more efficient than a traditional fuselage, since there is less drag and controbutes to lift.

Update:
Everything has been glues together and reinforcement spars have been added. I also drilled new holes in the plate for the motor mount. I tried to use hot glue for joining the wing halves, since it's always worked great on my EPP Superflys, but I just made a mess of it. The glue started to harden before I could get the spar inserted and it left a small gap between the wing and the center section. I ended up having to cut out the hard hot glue and used white gorilla glue instead. It was a mess, but I managed to get it together okay. I know, I know, I should have used 3M90 like I was told...I'm stubborn that way.

It was a bit of a challenge lining up the three sections, since the center has a slightly different airfoil than the wings. Plus, there is no wing bed for the center piece, so I had to resort to the TLAR method for getting it lined up.
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Old Jul 26, 2010, 11:03 AM
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Luckily I wont be cutting through any of the joints, so I may still be able to keep it pretty...
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Old Jul 26, 2010, 11:25 AM
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Sounds good just take it nice and slow

ck
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Luckily I wont be cutting through any of the joints, so I may still be able to keep it pretty...
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Old Jul 27, 2010, 07:07 PM
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Originally Posted by meshyx View Post
I have been using this launching technique on 48" wings, and it works well:

http://www.youtube.com/watch?v=KIBl94YnM3Q
I actually tried to launch my Zephyr like this and it kind of did a flat spin and went nowhere :P

And this thread is killing me. I wish I could unbuild and rebuild my Zephyr. Building is way more fun than flying :P
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Old Jul 28, 2010, 10:49 AM
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Originally Posted by AgentCow007 View Post
And this thread is killing me. I wish I could unbuild and rebuild my Zephyr. Building is way more fun than flying :P
I agree. I tend to build more than I fly. You could always just cut up your Zephyr and glue it back together....or even more fun, do a full speed nose dive into the ground, then glue it back together.
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Old Jul 29, 2010, 05:16 PM
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Quote:
Originally Posted by klique View Post
Yep 3 m90,lol some people will never listen
Gorilla makes it a pain to cut the bays due to its hardness and density in,it slows down the cutter and it makes for messy bay cuts.
3 m 90 gives you the time to align the pieces and you can cut through it like butter ,it makes for great bay cuts.

Hmmm does the 3M90 have enough hold to really keep the wing halves together? I understand the cutting problem with gorilla glue, but 3M just seems a little weak for the application. I guess I will have to try out some pieces and see how it holds.
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Old Jul 29, 2010, 05:46 PM
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Totally,,its the only way to glue the roots, you dont want the glue thicker and stronger than the EPP itself .
Your sparring and covering is the strength, if your foam is hard and tough in the center it makes for a messy area due to hard slow cutting.

Gorilla is the worst thing for gluing areas that will need to be cut out.,gorilla is good for the internal spars and skim coating in weak areas and thats it.

I am going to be doing a new method channel on u tube here soon, my new droid phone will alow me to do alot of crazy build clips that will really help you guys.

Quote:
Originally Posted by chimaera View Post
Hmmm does the 3M90 have enough hold to really keep the wing halves together? I understand the cutting problem with gorilla glue, but 3M just seems a little weak for the application. I guess I will have to try out some pieces and see how it holds.
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Old Jul 29, 2010, 08:49 PM
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Nice. You got a new Droid X?
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Old Jul 29, 2010, 09:02 PM
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No , I got the original because you can hack the heck out of it, the new one has all kinds of blocks in place against hacks now.
I wanted a bunch of stuff that you cant do on the X

We hacked it last nite and its sick now.

ck
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Nice. You got a new Droid X?
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