When i think about what makes a plane hover, it sounds like as long as you are at an equalibrium between gravity and thrust, you will hover (Assuming your plane has unlimited vertical). Why is it that some planes can hover and some cant. What part of the plane allow it to hover more easily than others?

Hand-eye coordination...

Yep...

It also helps if the plane is trimmed so that it's closer to the neutral stability point. This means moving the CG back to where the model does not pull out of a shallow dive by itself or may even want to steepen the dive if you leave it. And then there's the need for larger control surfaces with lots of throw and much of their area in the prop blast from the engine.

But even with all that the model must still be flown by a pilot with good perspective and quick thumbs.

Do either of you guys have "hover planes"?
I have some -tho frankly they are a passing fad to me.
The best of the bunch have:
A, 2-1 thrust ------------minimum
B, more length from prop to tail than wingspan.
CG? rearward location is helpful but NOT required.
My design critera for these models : You can never have too much power or a wing loading too low -
pretty well sums up the basics for a "hover" design.
The skill of hovering then is the same as learning to balance a basketball on one finger.
Some great "hover" flyers are not good aerobatic flyers --different ballgame.
Learning to fly a helicopter is a huge assist in seeing how this all comes together.

Like this?

yeh -tho this setup is more like what I was describing -

Setting the engine thrust so that no rudder input is needed for a vertical line is helpful. The plane should be hung like a "plumb bob" and balanced accordingly. The bigger the prop disc, the better. Low pitched props provide the easiest kind of thrust to finely control. The elevator shouldn't be "masked" by a thick airfoil. The quickest responding servos and tightest linkage will keep the pilot from having to play "catch up" with what the plane is doing. Hoverbatics is a "fad" that has rekindled my interest in sport flying, and hopefully by the time I reach age 80, I will have mastered it.

BTW, the more to the rear the CG is, the more the plane will only seem stable doing one thing, and that one thing is hovering. If a guy could devise a movable CG, then a truly stable and user friendly VTOL and horizontal flight model could be setup.

I started hovering in 1973, and found no great difficulty with it, as long as the ailerons had lots of chord and travel, and extended in nearly to the sides of the fuselage, and the rudder and elevators were large with lots of throw, AND you have at least 30% more static thrust than weight. Low pitched props deliver more hovering thrust in relation to torque, enabling the ailerons to more easily counteract engine torque.

One trick I like to use is to increase aileron chord in their inner portion that is swept by the propwash. Coupled flaperons also help - when I lose it in hover, it is usually in the pitch axis. Have never tried gyros, bit think that they would be a great help. I found that hovering tended to get old fast, and have never spent a lot of time at it, except when I was working out design details of a tail-standing vertical landing and takeoff model that has not as yet been built.

Make it extremely light with lots of power - all the rest is window dressing .
It becomes an exercize in vectoring .
Just like flying a really bad helicopter

HI ROTARYPHILE, The tailstander is going to be one of my projects this winter done in a 1/2A size. I want it to resemble something from out of a BUCK ROGERS cartoon. I have never used a gyro for anything yet, but something like this might need 2 sets of hands to fly. I agree that coupled flaperons give the best response, and with my MORRIS SUDOKOI, I just leave them on all the time. One last comment from me about hovering is the 4 strokes have a definite advantage in general in the side by side comparisons that I've seen, and give the pilot more room for error with throttle control.

First enough power is needed on the nose. Secondly large surface throws and/ or surface area movement. Thirdly lower wing loadings. I have actually hovered a friend’s trainer (PT 40 with 61 OS) but it was very difficult and not a whole lot of fun or consistent. With my OMP 540 it is very easy, fun and very predictable.

BTW I do not believe 3-d is a fad at all...just another step or branch in the evolution of our hobby. I foresee that as time passes there will be more enthusiasts pulled in by this endeavor and ultimately it will give way to a new class of modelers that primarily fly in venues that up until now were not even considered i.e. such as their own yard or other similar confines.

I think Dick was only referring to hovering being a passing fancy to HIM only as opposed to modeling in general.

Between the bunch of you I think we've covered the lot. CP brings up a good point about the CG for hovering actually favouring the unstable side of things and a possible adjustable CG being a good thing. This matter having been brought up before by a few others.

combatpigg, I was discussing the issue of a moveable CG in a plane and he had this idea. I haven't tried it yet, but it looks like it could be done pretty easy.

If you needed to make more extreme movement of the weight, you could use a bell crank and an arm extension.

No offence intended here but that is what most people think a hover is. It is also why it's hard to get an accurate flight report on a particular engine/plane combo. I hear so often that a particular plane has unlimited verticle with a certain engine. Many many times, my experiences just don't match up with what they think their experience was.

The yellow model I show, weighed 11 lbs with tuned pipe ZDZ40 - this was true -INSTANT unlimited performance - literally OOS vertically in a few seconds.
Unlimited in my book is a VTO setup.
My 13 oz foamies are also "unlimited " drawing 9 amps on a 4100 Himax.

HI COMBATPIGG: A practical tailstander VTO/landing model is a challenging project. I built a ukie tailstander many years ago with a throttle controlled .29, and found that while vertical takeoffs were easy, vertical landings were anything but. The main design weakness of my model was its conventional layout, resulting in its CG being a bit high above its bouncy landing legs, resulting in unpretty tipovers upon most landings.

My R/C tailstander design (not yet built) uses a tractor canard layout, to get the CG closer to the ground in vertical attitude, while the wingtips conveniently provide two of the needed widely-spaced landing support legs. A high vertical fin/rudder assembly provides the other point of attachment for a landing leg, with a retractible strut under the fuselage supplying the fourth. Each landing strut incorporates spring/shock assemblies stolen from model cars, since tail-sitting landings can be a bit rough.

A pusher canard with a bit of wing sweepback also appears attractive, but the prop is very close to the ground and a lot of dirt would be kicked up and ingested by the engine, so it would need a good air filter, and also probably an auxiliary cooling fan - pusher engines are notoriously hard to cool. Canards fly pretty much like tractors, and I want my tailstander to perform well in normal flight, and not become a one-dimensional oddity. A swept-back tractor flying wing layout also looks feasible.
The lower strut is retractible so that dead-stick landings can be done simply by skidding the model in on its belly or on plug-in conventional gear.

Engine overheating can afflict conventional layout models during prolonged hover - I usually limit hover duration to about 20 seconds. I selected a ducted fan .80 for prolonged hovering since a large head with plently of cooling fin area is available for it. Would love to hear how you make out with your tailstander.

Actually it was the Pig that I may be rebutting...if any at all...but how nice of you to notice Dick's response can be taken either way.

It's best left to helicopters and they are boring. You see a blob with a stick out the back and a blur where a wing should be. Boring. 3D flight with a helicopter results in the stick poking out in different direction (oh and the blur moves from top to bottom of the ball).

There is nothing exciting about seeing a bunch of airplanes hanging over the runway. I hover in my garage much easier. I have 30 airplanes hanging by the prop in the ceiling of the garage. Looks the same.

I do love the modern trend toward 3D flight. I have bought the stuff to build a fire breathing 8 oz foamy, one of the Shock Flyers (well - the airplane is in the mail) and am looking forward to it. All of my light stuff to date has been normal attitude flying only.

Flight should be done by wings.

3D flight in any size is a joy to watch but the main thing that needs to be addressed is how to do a series of high angle of attack rolls such that it doesn't look like the tail is dragging. The closest I have seen is the little machine that won the E-TOC. It could make rolls pretty much around the velocity vector even at low velocities (of course all the velocities are low).

That would be George Hick's design .
George earns his bread and board , working on aircraft design whut carry people.
He is not afraid to look at extreme ends of envelopes in design.
That's one reason why he won---

HI ROTARYPHILE! Sounds like you have given VTOL tailstanders alot more thought than I have! I like the idea of working some RC car hardware in also! Mine is going to have 3 identical delta wings[120 degrees apart], and an .061 stationed between each wing, also 120 degrees apart. The center section will look like a rocket fuselage with the ability for the nosecone to telescope in and out via a winch servo. That's how I will do the CG shift, and hopefully come up with something that is stable while in descent. If the 3 engine idea proves to be too much of a handfull, I'll just stick a .15CVA in the nose. I'll start a thread on it this winter in the 1/2A forum, see you there!