Blue_Moon_

3D is when you fly in a stalled state.

Amen.

PowerPlay

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Fun Fly and Profile planes were flying "3D" long before the term was coined. The term 3D really does not accurately describe what airplanes do, as opposed to helicopters that really are capable of true 3D or "three dimentional" flight. Obviously the term has become generic for high alpha and hovering flight primarly however, some would consider flat spins or a knife edge loop as 3D maneuvers. It is kind of like the famous words of a Senator a few years ago when ask to define pornography, " I can't define it, but I know what it is when I see it ".

For me the term 3D best describes a scale based airplane that has a wing loading light enough to prevent tip stalling, a power to weight ratio that will allow vertical acceleration from a hover and enough control surface area and throws to maneuver and control the aircraft in a stalled attitude. And last but not least . it usually implies performing these maneuvers at eye level or lower.

So how can you be sure you are flying 3D ? When the guys in the pits are giving you the Yeeeaaaahh!!!!!! or Woooo Hooooo!!!!!!!! you are probably 3D'n. Huck it knarly dudes

50%plane

My Feedback: (5)

Because of the hassle and overall added weight of their complex systems.


Woops

Shahid

3D is flying in 3 axis, thats where the 3 comes from.

Taken from www.3drc.info

The term 3D is arguably specific to RC Helicopters, but it has been adopted by fixed wing fliers too, and through publication, has become one of the RC World's everyday terms.

The normal motion of airplanes occurs in the 2D plane, or a imaginary plane that parallels the wings and extends to infinity. There is no "depth" to this 2D plane. All motion in normal 2-dimensional flight is restricted to that infinite plane. In other words, there is motion in 2 axis of the aircraft. Rolls, loops, knife edges, and hammerheads (among many others) constitute 2D flight.

3D flight is when the motion of the aircraft extends to all 3 axis, where the aircraft has a motion that moves out of the plane of flight. Examples of this are spins, hovering, blenders, rolling loops or circles, and lomcevaks, just to name a few."



Many thanks to Teryn DalBello for this definition.

Rcpilot

My Feedback: (78)

The UCD is the absolute worst 3D plane ever released.

The only reason why beginner and intermediate pilots think its so great is because it's the first plane they've banged a stick on after they soloed.

MikeEast

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LOL, agreed to some extent but I believe that goes beyond the simplist spirit of the question. In most every single 3D maneuver there is if you chop the power the plane will post haste be in the ground, UNLESS while descending, you can gain enough airspeed to get it to "FLY" again or get it back into a thrust vectored high alpha again, its not going to glide.
There is little or no flight happening in 3D, the plane is maintaining altitude or making a controlled descent almost purely becuase of thrust and steering by propwash and not by forward speed... I cant think of 1 3D maneuver where the plane will ascend if you cut the power.

As for the flat wing foamy thing,,, I get it but the plane is flying, maybe not by technical definition but simply put the plane is flying when its wings level. I will say this you are right,,, you chop the power and that bugger aint gonna glide is it?

Daniel Z

I surrender!!

Rebel1

[quote]ORIGINAL: STLPilot


Like Jay-Jay The Jet Plane?

Barry Cazier

My Feedback: (17)

The UCD is a great plane. I enjoy mine a lot. One of my favorite planes to fly. Mine will do an inverted rising flat spin. My Extreme Flight Yak wouldn't do a rising flat spin. Granted the Yak does things better than the UCD but the UCD does things better than the YAK. It's a good plane. Lighten up on it.

Thanks
Barry

rmh

Flat winged foamies do have a proper airfoil -make no mistake about that - needing a special set of curves to become an "airfoil" simply is not so.
Actually the flat wing on foamies is the best "airfoil" for that application.
3D- simply having enough thrust to do sustained maneuvers at up to and including vertically oriented maneuvers.
That's what a chopper does
Don't get lost in "airfoil" types as to which is best - that is an entirely different thing
fat airfoils are less sensitive to AOA.
Look at the logic
a flat plate generates huge amounts of lift at extremely low AOA
now visualise the airfoil getting fatter and fatter until it is round .
The amount of lift vs drag gradually changes places till you have only drag --which can be made to lift also but in a different manner -
Thick airfoils do NOT make more lift -making a better 3D model -they simply desensitize AOA and are easier o make strong due to cross section.
if you are designing your own "perfect 3D flyer " try to get the lightest model with the most static and dynamic thrust and use surfaces which react easily and predictably to prop airflow .
The best wingloading is subjective -but I favor pretty low loadings for slow stuff.
for fast tumbling stuff - smaller wings -

Rcpilot

My Feedback: (78)

Barry:
I don't appreciate being called stupid in a public forum

We have different opinions--leave it at that. No reason to resort to name calling.

rmenke

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Being one of those "Old Farts", I almost went off on you, but after a moment of thought, I reconsidered. THere are just toooo many of you kids out there for us "old Farts" to take on. How quickly we forget how we GOT HERE!

STLPilot

My Feedback: (21)

An "old fart" doesn't refer to an old person, it's an older fella that likes to complain about 3D. Ages usually range from about 45 and up. In other hobbies, like say fishing, that age can sway a few years in either direction depending on what part of the country you live in.

STG

My Feedback: (26)

You can tell that the UCD 3D is a 3D plane just by its name. It is true by definition. Not sure how you can argue that it is not. In fact, this is probably the best way to tell if a plane is a 3D plane or not. Look to see if there are any decals on it indicating that it is a 3D plane. For instance, look at my mini 3D. With the big 3D decals on the wing who could argue that it is not a true 3D plane? [sm=lol.gif]

If you want to do 3D slowly there is no substitute for low wing loading!!![sm=spinnyeyes.gif] Reynolds numbers are a big factor here also, as the bigger you go the higher the wing loading can be and still be able to "float". That means that the best scale planes(higher wing loadings) will not 3D as slow as the best non scale planes(lower wing loadings). Slower is not always better though.[&:]

STG

My Feedback: (26)

[:@] double post [:@]

YNOT

You know its a credible thread when Dick Hanson reponds.


I did this, IMO. Called the Frenzy. My concept, designed and built by Kris Welter in Concord, NC. Flew it at Joe Nall in 2004 (its on the DVD and Inside R/C Joe Nall show), looked like a fish. Everyone says it ugly, however when they see it fly they all said "WOW". 80 inch wing, 15 lbs with a BME 50 on a can with a Prince prop, full flying elevator with 70 degrees of throw and full flying rudder with about the same. Kris just finished the next generation of the Frenzy, better looking and as Dick said, smaller wings.

Wish I knew how to do multiple quotes..............The paragraph by STG about if it says 3D it must be 3D is down right funny. I have been telling people for YYYYYYYYYYYYEARS, just becasue it has a 3D sticker don't make it 3D. The license plate on my truck says YNOT 3D don't mean it 3D. Thats funny Dude.

famousdave

My Feedback: (61)

Being an old fart is a frame of mind, a choice. I know 30 somethings that are more uptight and snobby than many 60 somethings... it is possible to be young and ACT old. I'm in my 40s and act like 20's.... it makes for a fun life...

Life is too short to be uptight about anything.... just don't whine and complain and we'll all have fun and get along....

DP

MustangAce

My Feedback: (3)

Plane and simple.......post stall aerobatics.

mwarren400

To me....any manuever that Patty Wagstaff cannot do in her Extra 300S would be considered 3D.

Angus Balfour

I had doubts as to the validity of the content of this post, so I emailed an aerodynamicist/full size friend of mine who confirmed my misgivings. Here's what he said...

"Stalled wings are not something that aerodynamics books dwell on, because they are not much practical use. But let's start from "What is a stall?"
The stalling angle of attack is the AoA at which the wing reaches its maximum Lift Coefficient. Push it beyond that angle and it develops a bit less lift and an awful lot more drag. It's the drag increase that makes the aeroplane fall out of the sky as much as, maybe more than, the lift reduction.

These 3D models with very little weight and huge amounts of power are probably capable of flying with the wing at AoA beyond the stalling angle. I wouldn't like to analyse the flight or write equations for it because it's not something I have studied, but with abundant prop thrust overcoming high drag and helping to support weight, why not?

But at AoA below stalling angle (which could be from 6 to 12 or 15 degrees depending on aspect ratio and other things) these thin symmetrical or flat plate sections will behave fairly normally. The airflow will flow in streamlines around them, though they may have a bit of a separation bubble especially near the LE if it has a sharp corner. That might cause odd kinks in the lift curve, so sharp corners are best avoided.

The tails on regular models will virtually always be flying normally, i.e. not stalled. As long as the wing is not stalled the tail will not be stalled either I would say.

I'll bet these shock flyers spend a lot of their time not stalled either. Their straight cut depron wings may not be very efficient and may stall a bit early and may have little areas of separated flow near the LE but at low AoA they will behave quite normally. I would suggest wrapping the LE with tape to round them off a bit."

Shahid

Tape around the LE would cause a step for the airflow to flow over, creating an airfoil in essence I reckon (ish)

[X(]

YNOT

What about Sean Tucker and Kirby Chambliss and that guy who flys the Bulldog. All these guys hover and do harriers and HAKE.

2001 me and some freinds met Sean Tucker at an airshow we were performing at and he was amazing at the hovering and 3D tricks and now the full scale people are doing what we do.

Shahid

Interesting when you think about it, rc flying is based largely on emulating full size, you see it with large IMAC planes (and the schedules at are flown), scale, people scheming their planes based on full size or inspired by full size this or that.

But for once, it's the other way around!

Shogun

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My personal experience with this subject leaves me with a simple answer to the posed question. A GOOD 3D design is measured by it's performance BETWEEN the unstalled, stable flying state and the completely stalled, stationary flying state(hover). The worst designs show their flaws here in between those two states. Desings that are too stabele tend to snap and jerk around while those that are unstable will not want to fly well in the tradional manner. Sure you can hover a trainer but how much fun is it getting it into and out of that hover? The benchmark maneuver for all of this is the harrier, if the plane won'rt harrier it will be hard to enter and exit ANY high alpha state and as such becomes a poor 3D design....think UCD and you'll understand me. Also, when I say harrier I mean nose high, slowed down to a crawl and completely under control all the time. If your plane has a sweet spot you need to get it into to perform the maneuver it's not a good 3D design IMO.

In a nutshell its the transitional characteristics that make for a good 3D design.

rmh

Textbook aerodynamics specialists should really fly and or watch a few really good flat foam models perform before they make any decisions as to what is/is not a good airfoil for this type flying.
The textbooks apparantly don't include this type flight .
I am constantly being asked if a "proper" airfoil would not improve performance.
The flat foam panels are proper -for this application.
They operate perfectly under a relatively wide speed range and at ANY angle of attack.
What the hell else could you ask for?
The bookshelves of "airfoils" were intended for specific tasks - -none of them being THIS task