Discussion New Airplane Maneuvers

[Bohica35]

It seems like the XFC is a showcase for new and innovative maneuvers.

I have a couple of questions.


The tailslide seems to be a very common maneuver amongst the full scale airplanes. But I didn't see it very much at XFC.

I know that you can do a lot of things with models that you can't do with full scale.

Are full scale airplanes better at this because they are heavier? I ask because I am always impressed when a pilot can hold it (tail first) for a long time. So is it possible to hold it even longer with a model? As a spectator, I would be extremely impressed if a pilot could ride it tail first until the last possible second before pulling out. Is that even possible? It seems like it would be a show stopper.


Also, I know that all of the pilots can hover. But with the variable pitch props, is it possible to create negative thrust? I ask because, I think that at some point someone will hover nose first. Just imagine if someone would tailslide to a point when the plane falls nose in, then reverse thrust it to hold that position for a second or two..... Similar to an inverted heli hover... Is that possible?


I don't think you would be able to hold it for long since there would be no wind over the rudder to make corrections.... but even a second or two would be extremely impressive (to me anyway)


Maybe I'm an idiot, but I've already seen these pilots do things that I thought were impossible. So exactly where are the limits? Are these things possible?

Thanks

[kell0993]

Originally Posted by Bohica35

It seems like the XFC is a showcase for new and innovative maneuvers.

I have a couple of questions.


The tailslide seems to be a very common maneuver amongst the full scale airplanes. But I didn't see it very much at XFC.

I know that you can do a lot of things with models that you can't do with full scale.

Are full scale airplanes better at this because they are heavier? I ask because I am always impressed when a pilot can hold it (tail first) for a long time. So is it possible to hold it even longer with a model? As a spectator, I would be extremely impressed if a pilot could ride it tail first until the last possible second before pulling out. Is that even possible? It seems like it would be a show stopper.


Also, I know that all of the pilots can hover. But with the variable pitch props, is it possible to create negative thrust? I ask because, I think that at some point someone will hover nose first. Just imagine if someone would tailslide to a point when the plane falls nose in, then reverse thrust it to hold that position for a second or two..... Similar to an inverted heli hover... Is that possible?


I don't think you would be able to hold it for long since there would be no wind over the rudder to make corrections.... but even a second or two would be extremely impressive (to me anyway)


Maybe I'm an idiot, but I've already seen these pilots do things that I thought were impossible. So exactly where are the limits? Are these things possible?

Thanks

you need to check out some you tube vids of e toc 2009...tons of 4d flying.

[G.P.]

Look into the Turbo Raven. It had the ability to pull reverse pitch in flight and almost stop on a down line. Unfortunately it was destroyed and the pilot severely injured during a reverse pitch maneuver.

I think the reason that models can't hold a tail slide very long is because things happen faster on our models and we don't have the feedback that a pilot in the plane has. From the ground it's really hard for us to tell what corrections are needed until it's too late.

http://video.google.com/videoplay?do...92639009239481

http://video.google.com/videoplay?do...02328022&hl=en

[hpapilot]

Trying to hold a tailslide can be very difficult in varying wind conditions, and a huge part of our score is execution, or precision of flying. When the plane falls out of a tailslide, as will always happen at some point, it doesn't give the best impression of precision.

As far as VPP, it is not yet practical in gassers. It was tried a few years ago... To get just barely enough thrust for a nose-down hover, you needed a 100cc engine on a 50cc plane, and the power was still not good. Eventually we may see this, but we need a few breakthroughs first.

[kell0993]

Originally Posted by hpapilot

Trying to hold a tailslide can be very difficult in varying wind conditions, and a huge part of our score is execution, or precision of flying. When the plane falls out of a tailslide, as will always happen at some point, it doesn't give the best impression of precision.

As far as VPP, it is not yet practical in gassers. It was tried a few years ago... To get just barely enough thrust for a nose-down hover, you needed a 100cc engine on a 50cc plane, and the power was still not good. Eventually we may see this, but we need a few breakthroughs first.

just curious, why does a nose down hover require more thrust than a normal hover?

[hpapilot]

Originally Posted by kell0993

just curious, why does a nose down hover require more thrust than a normal hover?

Two reasons. Since there's no airflow over the control surfaces, we pulse the power constantly between forward and reverse thrust to "bounce" the plane and get some airflow over the tail. You have to have adequate power to hold altitude nose-down while also thrusting it forward several times each second. Secondly, symetrical prop blades are very inefficent compared to a traditional prop, so it requires more power to get the same thrust out of them.

RJ

[kell0993]

Originally Posted by hpapilot

Two reasons. Since there's no airflow over the control surfaces, we pulse the power constantly between forward and reverse thrust to "bounce" the plane and get some airflow over the tail. You have to have adequate power to hold altitude nose-down while also thrusting it forward several times each second. Secondly, symetrical prop blades are very inefficent compared to a traditional prop, so it requires more power to get the same thrust out of them.

RJ

wow....i always wondered how you could control it with no control surfaces in the prop wash and i thought i was cool cause i could torque roll geeez i better go practice, thanks ian.

[jatur]

Just for info, the tailslide used to be in the aerobatics schedule in the early days ( before FAI pattern) but was discarded because it was largely a 'luck' manoeuvre. Also, the model had to 'fall' forward to score, and with almost no surface control, this was very difficult to ( deliberately) achieve. jatur