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Feb 16, 2004, 11:53 PM
Park Jet Guru
jetset44's Avatar
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The VTO - A vertical takeoff 3D parkflyer


Thought I'd share my latest creation with the forum—a vertical takeoff and landing design I call the VTO (short for vertical takeoff). This is the most maneuverable and fun to fly airplane I've ever owned! It hovers with ease, does beautiful slow turning harriers, tight 3 ft diameter loops, spins around on a wingtip for quick turns, and then hovers straight down for a vertical landing. I regularly fly it in the street in front of my house, and even though the street is lined with trees on both sides, the model flies so slow and is so maneuverable that there's plenty of room to fly full aerobatics in just the 20 ft street width.

This design was heavily inspired by the recent JAR thread, so I have to give credit where credit is due for that great and simple design. The primary difference between the VTO and the JAR, apart from stylistic differences and the addition of vertical takeoff landing gear, is that it has a higher wing aspect ratio (1.5 vs 0.9). I did this for two reasons. One is to make the airplane float a little better in maneuvers (with an aspect ratio of only .9, the JAR really hangs on the prop), and two is to lower the vertical CG relative to the ground so the airplane is less tipsy in vertical takeoffs and landings.

Here are the specs:
Wing span: 30"
Wing area: 603 sq in
Weight: 10.7 oz RTF with 2s 1200 mAh battery (11.6 oz with 3s 1200 mAh battery)
Power: Stock GWS EPS-350C with D gearing (6.6:1) and 10 amp ESC
Propeller: GWS 12x6 with 2s battery, or GWS 10x4.7 with 3s battery
Construction: BlueCore foam with carbon rod reinforcement

If anyone is interested in plans, let me know. I'd be glad to post them and share the fun!

Steve
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Feb 16, 2004, 11:54 PM
Park Jet Guru
jetset44's Avatar
Thread OP
Here's a side view of the airplane. While the vertical takeoffs are easy (just add throttle!), I've found the vertical landings are harder than I expected. If you have any sideways velocity or get hit by a gust of wind at landing, the model will fall over on it's back (or belly). This usually doesn't damage the model, but does tend to crack the prop. If you catch it early enough you can add a blip of throttle to get it up away from the ground for a second try, but once the model is on the ground and falling over you don't want to add throttle lest the model grinds itself in….ouch. It's tricky but a lot of fun trying.
Feb 16, 2004, 11:58 PM
Park Jet Guru
jetset44's Avatar
Thread OP
Here's a flyby shot.
Feb 17, 2004, 12:02 AM
Park Jet Guru
jetset44's Avatar
Thread OP
Another slow speed flyby shot.
Feb 17, 2004, 12:05 AM
BOSS
j_z_123's Avatar
Awesome!!

Yes, plans please!!

Jon
Feb 17, 2004, 12:11 AM
Park Jet Guru
jetset44's Avatar
Thread OP
And this pic shows the obligatory hover shot...
Feb 17, 2004, 12:13 AM
Park Jet Guru
jetset44's Avatar
Thread OP
Oops, lost the hover pic...
Feb 17, 2004, 02:42 AM
Fly it like you stole it..
Tram's Avatar
I saw a guy at a ProBro funfly this summer who had a similar setup.. It was nuts..
Feb 17, 2004, 05:13 AM
JSZ
JSZ

plans


Very Cool, yes I to would like the plans, Thanks Steve
Feb 17, 2004, 07:29 AM
Registered User
CRASH GORDON's Avatar
jet set44,very cool idea,plans would be appreciated and well used.

cheers
Feb 17, 2004, 09:13 AM
edible_engine's Avatar
COOL! Can you send the plans to

[email protected] preferably both tiled and full sheet!

Ian
Feb 17, 2004, 10:44 AM
Registered User
MUDBOGGER2's Avatar
Very cool! I would love to get a set of plans. Tiled if possible.
Feb 17, 2004, 11:03 AM
Registered User
I would appreciate the plans also looks like fun
Feb 17, 2004, 11:46 AM
just playin with ma toys
coultam's Avatar
Pm'd you for plans m8


thx

Tom
Feb 17, 2004, 12:15 PM
Tee Sqaured
Thomas Manson's Avatar
I would love plans! Thats very nifty!

Thomas
Feb 17, 2004, 03:30 PM
Park Jet Guru
jetset44's Avatar
Thread OP

VTO Plans


Due to popular demand, here are the plans for the VTO in PDF format. Because this design is so simple, full size plans really aren't necessary. The plans below are formatted to fit on one 8.5" x 11" page and are fully dimensioned, so all you have to do is use the dimensions to draw out the parts directly onto the foam board. Some fudging might be necessary for the fuselage and canopy curves, but use your artistic license! For the circular wing leading edge, I just tied a string to a pen and swung a nice circle. Easy.

I'm eager to hear about other people's experiences with this design.

Steve

P.S. The attached file was created in Adobe Acrobat 6.0, so you might need the latest version of Acrobat to read it. If anyone has problems opening this, let me know and I can try another format.
Feb 17, 2004, 03:50 PM
Park Jet Guru
jetset44's Avatar
Thread OP

VTO Plans


Here are the plans in JPEG format, too. This version isn't as clean as the PDF version, but still usable.
Feb 17, 2004, 07:09 PM
just playin with ma toys
coultam's Avatar
thx for sharing m8


Tommy
Feb 17, 2004, 07:47 PM
JSZ
JSZ

Thanks


Yes, thanks again. JSZ
Feb 17, 2004, 07:58 PM
AV8
KsFlyer's Avatar
Sweet looking plane!


Troy
Feb 18, 2004, 09:31 AM
Registered User
MUDBOGGER2's Avatar
I have a question about joining the wing and fuse. Is the fuse slotted to allow the wing to slide into it? Thanks
Feb 18, 2004, 12:53 PM
Park Jet Guru
jetset44's Avatar
Thread OP
Yes, the fuselage is slotted to allow the one-piece wing to slide into it. Plus, notice there are two 1.5" tabs that are left in the fuselage slot that plug into two 1.5" slots cut into the wing. These tabs provide support, make for a stronger wing/fuse join, and eliminate the need for external bracing between the fuse and wing.

By the way, I join the wing and fuse together with 5 min epoxy, and I've learned you need to remove the film from BlueCore to get a good glue joint. So gently cut away a thin strip of the film on the top and bottom of the wing where it contacts the fuselage.
Feb 24, 2004, 03:35 PM
Park Jet Guru
jetset44's Avatar
Thread OP

Unexplained quirk!


Although my VTO flies great, it's got an interesting quirk that I can't quite figure out. Even though the thrust line is centered on the wing and the rudder is completely centered on the thrust line (equal area above and below the thrust line), the airplane has a pronounced yaw/pitch coupling. When I give large rudder deflections, the model pitches down moderately and also rolls slightly in the same direction of the rudder input. I expected the roll response due to the wing sweep, but not the pitch response. Anybody have any ideas what could be causing this?

Also, out of curiosity, has anybody else out there built a VTO or a variant of it yet? I've only seen one other (sierra aardvark's airplane).
Feb 24, 2004, 03:46 PM
AV8
KsFlyer's Avatar
We built a few similar models mid last year. They were variants of the "Sukalyn" A buddy and myself added some carbon rod to outside edges for takeoffs and landings. Never was very good at it though. It was easier to catch it in the air. But, I did have the occasional prop cut

Troy
Feb 24, 2004, 05:01 PM
RPV builder & operator
Pierre Audette's Avatar
Do you find you've got to put some right aileron on take-off, to compensate for torque roll?
Feb 24, 2004, 05:14 PM
AV8
KsFlyer's Avatar
THe ones I built we did. YOu also had to catch it from falling forward or backward depending on which way it wanted to go.

Troy
Feb 24, 2004, 07:01 PM
Registered User
My gues
Perhaps the "fuselage" in a flat rudder turn is blanketing a lot of lift at the back of the inside wing so your getting denser air on both sides of the outside wing,added frontal area, and higher airspeed to boot! Mostly the blanketing thing is my gues on the pitch though.
I just stared a moment to make sure i wasn't a spelling retard and realized less lift at the back means the plane is going to go UP- DUH!
So maybe its in the higher angle of atack needed with less efficiency in the wing and moving of the center of lift with this, or simpler if roll is INDUCED (from one or more of the above) this now makes the rudder into a DOWN elevator to some extent! Its like the egg and chicken thing.
Feb 24, 2004, 08:34 PM
Registered User
Aw shoot, now I have to build ANOTHER plane!
Feb 24, 2004, 10:18 PM
Park Jet Guru
jetset44's Avatar
Thread OP
Yes, I gotta admit I end up catching this model for landing most of the time. It's fun to try to land it vertically, but really difficult. Out of perhaps 10 tries, I've got two successful landings and two broken props! And it's SO easy to just hover it into my hand and catch it. Oh well, at least you have the option!

For what it's worth, I've been slowly creeping the CG aft and find I like how the model better with a more aft CG. Makes the hover more stable and the airplane that much more maneuverable. Just be sure you've got exponential to keep it from getting too sensitive on the controls. I'm currently at 7 3/8" behind the leading edge, which is 1/4" behind the location shown on the plans.

Pierre--no, I don't notice a lot of torque that requires aileron at takeoff. During hover you do have to hold a little aileron, but not a lot. The torque effects are MUCH more noticeable with the 2s battery/12x6 prop combination. With the 3s battery/10x4.7 combination, torque is much less. But I actually like the 2s option better since the model is lighter and the big prop acts like an airbrake when you throttle back, giving better speed control. Either combo will hover the whole duration of the pack so it's just a personal preference.

A Monell--thanks for the thoughts about yaw/pitch coupling. I'm still stumped...
Feb 24, 2004, 10:30 PM
3D Pilot
montu's Avatar
I got a question , how do you connect the wing in the body? Do you slide it in somehow? Also could u post full size plans so I can print it on a plotter. thanks


-Jordan
Feb 24, 2004, 10:55 PM
Park Jet Guru
jetset44's Avatar
Thread OP
The wing slides into the slot cut in the fuselage. However, there are two 1.5" tabs in the fuselage that plug into two 1.5" slots cut into the wing. These add a lot of strength and help keep things aligned. You have to contort the wing and fuselage a bit to slide the wing in around the slots, but it's pretty easy to get it in (the foam bends easily and then springs back to shape).

For full-size plans, PM me with your email address and what file format you prefer. The plans are drawn in TurboCAD, which can export DXF--the most popular exchange format.

Steve
Feb 24, 2004, 11:09 PM
Jordan,
Those tabs make the fuse really easy to align to the wing....slide the fuse most of the way onto the wing, lay glue onto the wing top and bottom, and push the fuse all the way into the slots...a couple of pins to ensure that the fuse stays 90 degrees relative to the wing when drying and you're done.....great design.

I've hit two trees, my boat and the ground with my version of this design and.....no problemo
Thanks Steve,
Kevin
Feb 25, 2004, 12:11 AM
3D Pilot
montu's Avatar
I think I need a pic of this to understand better. Sorry if I sound dumb.

-Jordan
Feb 25, 2004, 01:13 AM
Park Jet Guru
jetset44's Avatar
Thread OP
My model is built (and you can't see the tabs on a built model) so I can't show you photographs. But here are two cleaned up views from the CAD drawing. Below is a fuselage side view. I added blue boxes to show where you remove the foam so the wing can slide in. Notice how the forward tab is attached to the bottom of the fuselage and the aft tab is attached to the top of the fuselage (you cut at the top of the front tab and bottom of the aft tab). Once the tabs are cut, you can pry open the fuselage to slide the wing in. Having a tab on each side allows each half of the fuselage to attach solidly to the wing.
Feb 25, 2004, 01:14 AM
Park Jet Guru
jetset44's Avatar
Thread OP
The drawing below shows where you cut slots in the wing to accept the tabs. Again, the blue boxes show where you remove the foam.

Hope this helps!

Steve
Feb 25, 2004, 01:17 AM
Park Jet Guru
jetset44's Avatar
Thread OP
I should also add that the wood motor mount should be glued to the WING first, and then after you slide the wing into the fuselage, you glue the fuselage sides to the motor mount at the same time you're glueing the wing in.
Feb 25, 2004, 01:24 AM
Park Jet Guru
jetset44's Avatar
Thread OP
Here's a closeup picture that shows some of the details of the radio installation. You can also just barely see the slot where the forward tab is just behind the servos...
Feb 25, 2004, 01:36 AM
Steve,
It looks like you used pull-pull controls?

This is the first close-up that I've seen and it's impressive!

Aaaargh, now I have to reconfigure the controls on my ver.....

Kevin
Feb 25, 2004, 02:54 AM
Park Jet Guru
jetset44's Avatar
Thread OP
Yes, I used pull-pull controls for both rudder and elevons. I use pull-pull on all of my parkflyers whenever I can--they're very easy to set up, weigh practically nothing, and provide solid control. I highly recommend them for these kinds of models. Make sure to use Kevlar or Spectra threads though, since they don't stretch.

Steve
Feb 29, 2004, 11:09 PM
Registered User
Where do I get the Kevlar or Spectra threads? From walmarts craft/sewing section?
Feb 29, 2004, 11:30 PM
Spectra is a material used for fishing line like Power Pro or I think Spiderwire, you'll probably find it at Wallymart in the sporting goods

Prestretch it by wrapping around a table leg and giving it a good pull, and make sure that you use CA on the knots or they will untie themselves, some go as far as to scrape the line with a Xacto blade before tying and CA, claim that it holds the knot better, haven't done that and haven't ever had a knot come undone.....50# test is a good size to work with
Feb 29, 2004, 11:35 PM
Oh yeah, if you do any bass fishing....this stuff will cast a mile it's so slippery in the guides and will break your pole before it gives way pulling in a 'fattie'
Feb 29, 2004, 11:46 PM
Registered User
LOL! Thanks for the info! I'll have a look
BTW: In the Fuse, did you cut out the part for the motor mount?
Can you provide a front shot of the plane so I can see how the motor mount is mounted, wood piece and foam is cut?

I now have the wing and fuse cut to shap and need to connect them
Thx again!
Jeff
Mar 01, 2004, 12:05 AM
Jeff,
I don't have any build pics, but I just cut out a 3/8"slot in the fuse and the wing, centered and when I assembled the wing and fuse, I just wiped in some Gorilla glue into the foam slots and put in the basswood motor mount, leave an inch of wood sticking out from the wing/fuse and make sure that you remove the "backing"/"skin" from the wing foam to get a good glue bond, just make a very shallow cut along the bond line between the fuse and wing, and peel the backing off....use some pins to keep the fuse and wing at 90 degrees to each other and to hold the motor mount in place.
Mar 01, 2004, 12:28 AM
Jeff,
I forgot to mention that in the first build I pulled all of the backing off of the top of the wing in order to paint the top, not a good idea as the packing tape would not stick to the painted surface very well...every flight required that I push the tape back down, and I was very concerned (Ok, well somewhat concerned, it is a bluecor cheapie) that the control surfaces would come undone in flight....I've rebuilt, leaving the backing on both side to avoid this issue.....here's a pic of the wing and basswood laid in...
Mar 01, 2004, 12:31 AM
Oops, as you see there's about 2 degrees of right thrust correction on the motor stick, I don't put any down correction....with that much wing, it doesn't seem to need it
Mar 02, 2004, 02:02 PM
Registered User
Can I get this basswood at Home Depot? Do I just ask for it by name or what? I know they carry gorilla glue so I'll pick some of that up too
Mar 02, 2004, 03:09 PM
Park Jet Guru
jetset44's Avatar
Thread OP
I doubt Home Depot carries hardwood strips that small. But most hobby shops and even most crafts stores sell it.
Mar 02, 2004, 03:28 PM
Registered User
k, I just figured I'd buy the wood and cut it down to size.
Mar 02, 2004, 03:51 PM
Registered User
Also, do you glue your gearbox to this wood block or screw it in? I'd hate to make it permanent.


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