1/8 RC B-52 Destroyed in crash

Your reading too much into this.

From all accounts it was definitely the high wind, and overly aggressive maneuvering in said high wind.

It also mirrors perfectly a real B 52 crash. (same attitude, and result)

I remember a solution from the good old days when radio control was a rartiy. This was to have a weighted pendulum inside the fuselage that was linked to the control surfaces - I think it was the elevators and rudders. That solution was expected to keep the free flight plane flying level and straight (or was it trimmed to fly in a large circle?) until the fuel ran out. Beyond reading that in a magazine article I haven't seen that solution used. This pendulum solution has the makings of a simple artificial horizon. Perhaps if the model's attitude is inclined too far in any direction it could close a switch to reverse the control surface position until the pendulum is in neutral again.

I was thinking more generally as I've seen many moments of the controller getting a bit puzzled as to the attitude of an aircraft as their mind plays those nasty tricks "it's banking away, no it isn't, yes it....no wait!"

It depends on if it can be reprinted ?

Richard.

That's a neat idea! I seem to remember that from the old days when radio control meant new 'top hat' transistors and elastic bands were still king.

It could be possible to use the same system reading the output from a humble mouse circuit, slapping a short weighted rod to the shaft and radioing the output back.

Reading Kurt Laughlin's post in this thread, it's all possible now, thank god.

Richard.

"> Actually, this looked more like some sort of control failure to me -

I got the same feeling - it leveled out OK so either a surface got loose - or he just went far enough off to stall it. Does anyone know if this was a first flight.

Val Kraut

Actually, if you want to get up to date (actually I'm of the good old day school myself) check out some of the new RC mags. Solid state gyros, complete programmable autopilots systems for loss of signal recovery. Wow!

Actually, what the R/C speed guys used to use was an electrostatic wing leveler. Two devices - one in each wing tip - would sence a change in resistance due to one wingtip being higher than the other and feed a bias into the aileron channel to level the wings.

Worked well. I'd bet the system is in use on RPV's. Much simpler - being entirely solid state.

"Rufus" wrote

My guess is the fully integrated, inertially guided, GPS updated, programmable, "solid state", autopilot systems are more in vogue.

KL

Maybe, maybe not...when you consider the effects of jamming...

Yes there were/are three other videos of it flying before. An amazing sight !!

And I cant figure out how you guys seem to keep coming up with it being a control problem, look at the flying surfaces, ONLY when he banks to the left, does it *stall* and fall to the ground. Nothing appeared to fall off, and or be out of position. Listen to the WIND when this happens.

I've now shown this to a LOT of people who spent their entire lives working on, or flying real aircraft, (and RC's) and they all agree with it seeming to be a high wind, combined with an aggressive turn. You guys keep looking for a complicated answer, when the obvious is staring you in the face.................

I would LOVE the builder, pilot, or on scene witness to straighten this out !

Again this goes back to the old days when a two channel RC was a luxury. I do recall that the solution to control large RC aircraft (6 ft span Wellington?) with only two channels was to make it inherently stable and have elevator and ailerons only. Ailerons were used to effect gentle turns and it seemed to have worked quite well. It seems sailplane pilots commonly use this maneuver.

Perhaps for this B-52 the pilot could have used ailerons to effect gentle turns instead of using the rudder. With the sharper (aka more aggressive) turn one wing would drop much lower than the other. This attitude likely caught the wind and the wing acted like a sail to speed the model into the dive.

If you do not get a GPS update you go to the inertial guidance.

You use the ailerons mostly when you turn and not the rudder. Look at a flying wing as an example. No rudder there at all.

Talk to some folks that have investigated some actual aircraft crashes...or some 757/737 pilots...but yes, I'd like to hear from the pilot...

Since we don't really know which way the wind was blowing, we can't really say much about how it contributed. And judging from the attitude and yaw rate I see in the video, I'd still say that the jet hadn't actually stalled.

Not to mention that I can't recall if the model actually had ailerons, or just spoilers for roll control...I'll have to look at the pictures I have of the airplane which I saved at work. If it did only have spoilers for roll (like an MU-2, a P-61, and/or posssibly a full scale B-52) it may well have encountered a gust and not had enough roll power to recover. But we can't really say for sure without knowing the direction of the relative wind, the speed of the wind, and the speed of the jet.

Another thing which may have happened is that the jet lost one or more engines on the port side, and that asymmetric thrust is what is producing the yaw we see in the video. But I personally don't think this is what happened either.

A characteristic of any swept wing aircraft is a tendancy to snap roll into the trailing wing as yaw angle builds (we had a guy kill himself in a QF-86 due to a combination of this and a possible asymmetic slat deployment during yaw some years ago while improperly crossing a ridge line). It's an areodynamic fallout of the geometry of the wing as it presents the airfoil to the free stream when yawed - the "leading" wing sees a higher effective dynamic pressure across it's span and thus produces more lift than the trailing wing (similar to the problem with the retreating blade on a helo during forward flight - solved by cyclic pitch, if I remember right). Once the snap roll starts the only way out is to reduce the yaw - if you run out of rudder before the yaw sops building, you're dead...so again, we're back to control authority.

This is probably the most likely scenario - the pilot made an agressive turn, let the yaw get out of hand, and the jet snap rolled - not stalled. If the wind was in the right direction, it may have contributed to the snap roll.

Yup. But if you don't have the space or payload for a full inertial system, you might be forced to use something simpler...and lighter...or cheaper...

In any case, yes - you design a redundant system.

And differential thrust, probably.

But the real answer is that for a conventionally tailed aircraft you use both - rudder and aileron - at the same time, in order to keep the turn coordinated.

I assume that the plane would fly into the wind for the takeoff. When the B-52 made the turn to get back into range one wing dropped and presented the surface of the whole wingspan to the strong wind (from the left hand side of the video).

Remember, as kids we used to stick our palms outside the car window to zoom around like a jet fighter? Putting the flat of the hand against the airstream would result in interesting things.

My father worked for American Airlines for 45 1/2 years. Started as a mechanic, rigger, (A&P) on VS 44a (all three :) PBY's, PBM 5's, Coronado's, (also Tigercat with prop spinners) and then moved on to jets. Much flight time. (sys tests, flight checks, etc.) Most all in heavy A/C Moved his way to management, and worked his way up He has been on several serious accident investigations. (Air Florida for one, and several others) Both he, and an ex SAC friend (KC 135 crew chief) watched the video and aggreed or rather told me what they thought, which is what I posted here.. Everyone who has seen it is bummed !!

Watch the beginning of the video, and it appears comming from left ot right. It also appears to change direction a few times. Look at the grass, trees. No question it was cranking that day. I used to build and fly sailplanes, large ones, and a wind as hard as that gusted, would have ripped one apart. (and did once, a VERY painfull expirence...)

It has the same spoiler control surfaces as the real B 52. There are three videos of it flying before the final video. Take a look, well worth it

Ok works for me, and at the same time there was no question that the wind was gusting, and therefore impacted his maneuvers, and left him with a smaller margin of error. It did go down very fast, and literally just fell out of the sky :-(............

My father does have some very funny stories about people doing just the most stupidest things, and getting into serious trouble. Most of them got away with it, some didn't.............. Someone asked him once did he ever lose an airplane ? He replied, "I never sent one up that didn't come down"

Or as Buzz used to say, "Gravity is flawless" BTW, anyone see him recently ??

"Only A Gentleman Can Insult Me And A True Gentleman Never Will"

I should have also included heading in m list of requisite data...it does look as if the jet was indeed heading downwind, but not on such a heading as to make the crosswind component much of a factor, IMO.

Besides, the "hand out the window" experiment and the coordinated control of an aircraft are two distinctly different subjects.