B52 Crash Video's

Interesting indeed. Considering the BUFF's flight characteristics and the high wind, I suspect this one can be chalked up to pilot error! He never should have pushed the throttles forward. I would say it is vivid proof of the dreaded "Downwind Turn" phenom! :)

However, the resultant smoke and (I assume) fire was a nice scale touch.

I have another explanation - at the last stage, the plane was doing a bank to the left, but due to optical illusion I was first inclined to think it was actually banking to the right. If the pilot suffered from a similar illusion, he would correct the "right" bank by rolling it to the left - causing the already banking left plane to almost roll and dive.

This "inverted move " illusion danger has caused me to create wildly different color schemes for top and bottom side of wing on my models - but this would obviously not do for this model...

A small model can be "caught" if you give it incorrect control input - a large model would be less forgiving.

What a waste of a beautiful plane.

Nah. It was due to a down-wind turn.

;-)

I won't say you didn't see it that way and it's possible the pilot may have too. But, I never even considered such from the videos.

I suspect he went into the left turn and a combination of things happened. First his air speed was dangerously close to a stall and he didn't realize it because his ground speed was faster than normal. Second, the wind was blowing pretty good. That wind sock was about as stiff as they can get. So I suspect the second factor was that big, broad wing being turned into the wind where the wind can leverage it and push it around. Literally! And third is the fact that the B-52 does not have ailerons. There was a spoiler working hard on the top of the right wing but nothing on the bottom of the left to help it out. And the last was gravity. Once that left wing was down, gravity grabbed hold and the rest of the plane had to follow.

Chuck

| I suspect the second factor was that big, broad wing being turned | into the wind where the wind can leverage it and push it around. | Literally!

Wind does not do that.

Once in the air, your plane has no idea how much wind there is, and just doesn't see it, and therefore does not fly any differently, as long as the wind is smooth and steady.

Wind complicates things in three different ways --

1) Wind makes it *look* like, to somebody on the ground, that the plane is flying differently. Downwind turns seem much wider, upwind turns seem much shorter, etc. If the wind is strong (compared to your stall speed) you can be hauling ass downwind, at least from the viewpoint of somebody on the ground, and yet be barely above stall speed. Or you can be `hovering' in place as you fly upwind.

2) Changes in wind speed/direction will have an effect on your plane. If you're flying downwind just above stall speed, and there's a gust of wind, your plane will stall. Or if flying upwind, just above stall, and the wind slows down, same thing.

Also, as you get closer to the ground, the wind usually slows down. When you're landing upwind, this will help counteract the ground effect, and your plane will land quickly. But if you land downwind, your airspeed will increase as you get closer to the ground, and you can easily take up your entire runway and the field beyond it (hopefully it's a field, and not trees) if you're not careful.

3) wind generally causes turbulence, which is another thing that isn't just a matter of perception.

Still, it's too bad about the plane. It was truly a work of art ...

Oh yea, wind DOES do that. I fly giants exclusively and I can promise you that when the wind is over 12mph, and turning away from the direction of wind, the high wing has a tendency to lift MUCH higher than in a normal turn and I often have to give reverse aileron to keep the bank angle (down) where I want it.

MJC

I noticed in the video that the right spoiler did not move up untill the wing was almost 90 degrees to the ground. The real B52 does not have ailerons because the wings were so flexable that it would change the incidence of the wings if ailerons were used. Wether the model had ailerons is probably up to the builder,the wing could be built strong enough to use ailerons on a model. Im sure he probably built the model to scale and didnt use ailerons,but it sure would have been more controlable with ailerons on the model. DOUG

| Oh yea, wind DOES do that.

No, it doesn't. It's all in your mind.

| I fly giants exclusively and I can promise you that when the wind is | over 12mph, and turning away from the direction of wind, the high wing has a | tendency to lift MUCH higher than in a normal turn and I often have to give | reverse aileron to keep the bank angle (down) where I want it.

It's all a matter of perception. As long as the wind speed is steady and unchanging, your plane does not fly any differently. It just

*looks* like it flies differently, and you may therefore fly it differently.

And to respond to jim breeyear, wind sheer is *not* an example of a steady, unchanging wind. Not that you have to have a `windy' day for wind shear. Thermals are created even when there's no real steady wind at all, for example. And ...

In a turn the lift vector is no longer pointing up, but in the direction of the turn.

Well, a portion of it is in the direction of the turn, unless you're banked at 90 degrees. Not that this has anything to do with wind or wind shear.

| > | I suspect the second factor was that big, broad wing being turned | > | into the wind where the wind can leverage it and push it around. | > | Literally! | >

| > Wind does not do that.

I'll say it again. A steady, unchanging wind does not change any aspect of how your plane flies. It does not push one wing up and one down, increase or decrease your stall speed, or even make turns tighter or wider, upwind or downwind. It just changes how it looks like it flies with respect to the ground.

Now, when you get really close to the ground, things change a bit, because the wind speed goes down as you get close to the ground (it can't be steady/unchanging anymore.) But I covered this in my previous post.

I imagine that full scale pilots, especially IFR rated pilots, know this already. But it's a bit easier for them, because they're up there in the plane and can feel how the plane is flying, and don't have to rely on their eyes looking up at the plane from the ground.

Therin lies the myth of the downwind turn. Most people fly their plane different upwind vs downwind because of the perceived difference in speed. The plane doesn't care how fast the wind is blowing as long as it is relatively steady. Once it is in the moving airflow, all of its movements are relative to the air mass. The earth no longer has any influence (except for gravity and turbulence near the ground) over the model's actions.

Hi, Paul.

After flying models since the very late fifties, it still amazes me how this obvious concept can be so difficult to grasp for some folks.

Ed Cregger

Not to mention these aerodynamic rules are pounded into you during your training, as well as the debunking of all the myths...

I have seen the videos also, but I am not convinced that wind shear was a culprit. Maybe a simple stall and spin, or some sort of mechanical failure perhaps. To bad though, that was one fine model and a loss for many in the modeling world. rick

My Model Aircraft Home Page

OK! Try this. Take something like a 2x4 ceiling tile. Stand outside facing a 20MPH breeze. Holding one end of the tile raise it so it is horizontle like a wing in level flight and the free end is pointed into the wind. Now begin to slowly lower the free end toward the ground and see what the wind does to you. Maybe the plane doesn't know the wind is there but believe me, the passengers will. Been there! Done it!

One of the earlier videos I saw of it showed a full flight, takeoff through landing. When it taxied into position for takeoff, the out rigger wheels were firmly on the ground. When it landed and stopped, the out riggers were off the ground. Difference is wind flex due to fuel load or lack thereof. Just like the real one! Nice scale touch!

Chuck

I think the point you're missing is that the actual airplane wing is not attached to feet planted on the ground. Once the aircraft is in the air, it is a part of the air mass, not the ground.

Here are some references I dug up using Google:

Of course, if you don't believe these folks, stop by your local flight instruction center and talk to a CFI. I'm sure they would be happy to help.

OK, hold that same ceiling tile while some guys strap you into a harness that is attached to a strong rope that is suspended from a hot air balloon. The guy operating the balloon turns on the propane and the heat causes the balloon to rise, taking you up into the air with it. What do you feel on the ceiling tile?

Answer: Nothing once the balloon is moving along with the prevailing wind. The same thing happens to a model once it is airborne. Once airborne, there is no wind.

There will be turbulence caused by ground effects, but they are temporary and varying in direction.

Ed Cregger

It's simply amazing how long it is taking this guy to get this concept.

The video that I saw only showed ONE outrigger remaining at the end of the flight. I didn't see it fall off or on the runway... I would suspect that it may have come off upon landing, but no evidence.

--- Rich