wonwinglo

*** What a sad sight Ad,thanks for bringing these pictures to our attention,just think of all that money involved and what we could have built with it between us ?

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'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

Bluewavestudios

Adzam,

Indeed this was the very same B52, Believe it or not, it is to be rebuilt as well...!!! Recent post on Newsgroups on alt.binaries.models.scale revealed this info.

More on the following links:

http://www.rcuniverse.com/forum/m_21...tm.htm#2129019

http://www.stukastudios.se/b52.htm (this is the link to same pics as you mention above)

and finally:

http://www.rcuniverse.com/forum/upfi...08/Mk26062.jpg

Regards.........Mark.

Wowbagger

I was at the Nats on the Saturday and watched this aircraft fly. Now my views may upset a few people but nevertheless I believe them to be true.

In my opinion this aircraft should never have been flown in the prevailing conditions. I watched it lurch around the circuit with big pitch changes and serious wing flex/twist evident. I felt it was so bad that I went back to the trade stands in case of an incident. It flew again later on and displayed the same handling characteristics. A couple of days later I was downloading the video of the, not unexpected, crash.

My worry is that if one of these things gets into a crowd of spectators, we can expect serious limitations in the operation of our models. It'll focus establishment interest in us. To fly machines such as this at public displays is courting certain disaster. The Nats may not be too bad as there is good crowd/flight line seperation, but we can all think of plenty of shows where this seperation is very close indeed. The results of the B52 in a crowd just doesn't bear thinking about. You have people buying radio gear close to the flying and obviously switching it on at their cars, which in this case were even closer to the flight line. It's no good saying they shouldn't do it, they do do it!

In my opinion these projects are not properly researched and I'm suprised that full size flying notes were not taken into account by the people building and flying it, and (I assume) the LMA inspectors who must have inspected it at various stages of its construction.

It is all very worrying. A couple of years ago a big Lanc' tucked in at a show during a high speed pass. In Henshaws book, "Sigh for a Merlin", he states that a Lanc' will enter an uncontrollable "tuck" at speeds above 320 IAS (if memory serves!). If the builder/flyer had have thoroughly researched this aircraft the crash could have been avoided. It's highly likely for these large machines to exhibit the same flight characteristics of their big brethren.

I've watched LMA pilots at shows hauling very large models into the sky time and again. The pilot obviously having no real understanding of what he's doing. I watched another Lanc' abused in this way at Weston Park last (I think) year with the inevitable stall and, fortunately, left wing drop into a tree. If it had been right wing drop he'd have been in the crowd. This year it was a jet jockey showing off his (very poor) knife flight skills, the model threatening to pull into the crowd time and again, the pilot obviously flying beyond his capability. He too found a tree and totally destroyed the model. At full size shows any deviation from prescribed shedule means an instant landing. It should be the case at large model events too. A 250 mph jet may be exciting stuff but a glitch putting the model out of control at these speeds frightens the life out of me. Imagine a 15 pound model hitting someone at 250 mph. A half second loss of control could easily put such a model into the crowd line.

250 pound models built of skinned blue foam just doesn't get the job done. This size of aircraft should come under CAA inpection in my opinion. I also think commercially available mass produced radio gear (TX and RX) is asking for trouble too. These items should be subjected to some form of reliability testing before use. Even a special frequency should be considered. Batteries and so on should certainly be CAA passed.

I'm afraid terms such as "terrific achievement" and "super model" leave me completely unimpressed. This thing was an accident just waiting to happen. By the grace of God it didn't fly off into the crowd and kill/burn a couple of families with kids. Let's get on it before it does happen.

wonwinglo

***There are some valid comments in what you say and I would like to add a few of my own gleaned from large model pilots/builders etc and the general concensus of opinion,firstly when a model is scaled down to such huge proportions as the B-52 the same flight envelope as the real machine should be observed,for example in the case of the B-52 it is well documented and known that any increase in bank dramatically affects this swept wing bomber,the number lost in Vietnam alone showed that due to evasive action the bomber would slide sideways out of the sky out of control,the models built of the B-52 in reent years have displayed this characteristic unfavourable behaviour,it has to be said that any model is only as good as its pilot and just how do you get training on such monsters ? very specialised stuff indeed,it looks likely that the CAA will take note of what happened and probably stipulate that pilots will need training-as full size pilots,sounds like a bit of an overkill but this has been on the books now for some time,in a lot of ways it will kill the large model business but awareness is better than one big accident just waiting to happen.
One thing that does concern me is the apparent lack of regard for some aspects of stability and the way the model handles,from observations of video footage it was obvious that this model looked very sensitive in the fore and aft trim constantly requiring pitch trim changes,perhaps the centre of gravity/thrust lines etc were not quite right,lets face it getting a small model trimmed is bad enough but to balance out such a monster as this needs lots of extra special care,it only takes a few degrees out of trim to cause problems.
Whilst I know that there are dedicated inspectors operating throughout the country to periodically keep an eye on such projects the inflight stresses on even a very basic ultralight aeroplane require a very experienced stress engineer to carry out the calculations,when you are dealing with large chunks of foam with stressed skin covering the displacement of metal fittings needs to be carefully worked out,the stressmans job is to work out the loads under what he expects the aircrafts ability to handle in terms of g-forces,every little rib and fitting needs to be calculated in terms of what can it do ? in the case of foam/veneer blocks which is how a lot of these large models are made a relatively unknown factor has to be worked on,this became apparent when the glass skinned foamies such as the Quickie,Rutan designs came about,as it happened a new problem came about-leading edge wing behaviour in rainy conditions,the first one third of the leading edge of the wing developed strange behavious.
So what I am saying is the inspection is only as good as the known elements of aircraft design and construction,it has to be based on sometimes tenuous formulae.
Whilst not wishing to stop the production of these large models,I do feel that not enough design consideration and stress calculation is taken into consideration and the inspection side needs to be looked at more closely otherwise accidents like the one that happened to this model can and will happen more frequently.
Anyone who has seen a PFA inspector at work will know what I mean,no stone is left unturned in the interests of safety,if it will loosen or break then everything needs to be considered.
( Part 1 )

__________________
'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

wonwinglo

One thing that has developed over the past few years and in particular since the advent of model turbines,has been the interest shown commercially in models like this,most people now know that this project was built to advertise the products of Wren the engine manufacturers,nothing wrong with that,however what must be understood is that just like any commercial sponsorship there are pressures.
The model was contracted to fly at public shows,as we all know sometimes the pressure to fly in conditions that are perhaps unsuitable are governed by circumstance,the operators give us assurance that the model was perfectly capable of handling a strong crosswind and had been checked out in same,the sheer logistics and pressures of an operation such as this need to be looked at in the light of their opeation,the British nationals would mean a lot of potential in terms of getting her airborne which they did.
Judging from the video coverage it was apparent that the operation was covered as safely as could be in terms of actual airspace away from the crowds,it would have been a CAA requirement anyway that the model was flown in front away from the crowdline just like any full size airshow,personally I would feel much safer seeing something such as this in flight as some much smaller models at public shows but we have another element to consider that has come about because of the sheer nature and of the power units of these models-Fire.
It has been proved now that such motors can and do explode on impact,a phenomenon virtually unheard of before,there have been cases in the States whereby jet models have crashed into fields of dry crops and set the whole field alight,this could prove a few problems with the insurance side for the future.
So on reflection there is room for improvement,to re-iterate-
1/ Better inspection more akin to a full size homebuilt aircraft with due consideration to known stress factors,logs and tables.
2/ The training of inspectors/engineers to undertake such work on behalf of the authorities,perhaps an extension of what the LMA are already doing but with more consideration given to machines which will be known to be operating commercially at shows etc and are exposed to the public.
3/ The better training of pilots for operating such models,with a real need and understanding of the operating limitations of such very large models.
4/ The need to perhaps have a design organisation undertake sresss and design criteria for such projects and to make such knowledge more freely available for potential builders.
Without seeing such large models grounded there are certainly considerations of safety to be considered that were not before apparent,let us just hope that this is just a warning as to what can and will go wrong.
After all full size machines fly over our heads every day safely,it is always the one that goes in that will cause the concern such as this one,yes they do look impressive and command praise for the sheer dedication and skill of their builders,but the writing is on the wall for the future to tighten up the act of building and operating such models will require just a bit more thought with regards for public safety.
What is now needed is for a meeting of the LMA with the CAA as to the way such projects will need handling in the near future.
The BMFA will conduct their own enquiries as to the future of handling such models at future events as the nationals.

__________________
'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

duncan

Very pertinent comments Onewing. My tuppence worth is that the port wing stalled, all that sweepback, low power etc. On a related topic regarding crashes and safety , read the correspondence in RCM&E, Oct `04. David Boddington and Idris Francis (Flight Link Systems) have differing opinions on fail-safes. I await the LMA`s report on this and the B-52 crash. Fatalities connected with aeromodelling are not uncommon but one concerning a fast jet with burning fuel and the press will make the most of the story. Repercussions would be greater restrictions right across the modelling spectrum.

Wowbagger

Just thought I'd update you all, in case you hadn't heard. It now looks like pilot error. He says he looked away just as the bank was starting and when he looked back at the model was disoriented.

Pretty easily done as the first time I watched the video, and not really paying that much attention, I too did a double take. It appeared for just a moment to be turning towards me, i.e. right.

It makes you wonder though, because he must have known what control inputs he was using...

Nevertheless, respect is due the pilot, no names no pack drill, for admitting to his error. It has certainly saved a lot of speculation and the possiblity of restrictive rules coming into being (or not!).

Wowbagger

They salvaged one engine...

Attached Images

DSCF0019.jpg (88.9 KB, 15 views)

Pete1978

The B52 wasn't fitted with ailerons, instead it utilised spoilers for roll control, these are less effective than ailerons. Full sized B52's have also encountered the phenomenon that caused the crash of the model B52, one such occured at Fairchild AFB in 1994 and is well documented, the crash can be seen on several websites and the similarities in the departure from controlled flight of the model and full sized aircraft are strikingly similar. The investigation into the model crash uncovered that the pilot had an orientation issue (as can be seen on the video, it was a blustery and overcast day - a typical bank holiday weekend), he accidentally exceeded the angle of bank at which the spoilers would remain effective exactly as stated on the previous post. I personally witnessed the B52 crash and have been to the BMFA nationals annually ever since. Since the B52 crashed there has been a complete lack of large scale models at the Nationals and in my eyes that's a real shame, for a 'national championship competition' it's not as interesting as it used to be and no longer the great advertisement for model flying that it once was. Just my tuppence worth!

wonwinglo

Thanks for the follow up Pete on this old thread,yes you are correct in stating that spoilers are different to aileron control,the effect is like a barn door dragging the wing back as opposed to increased/decreased lift with conventional controls,much more difficult to pull a wing up quickly,spoilers are also used on sailplanes and gliders to give a draggy effect for landing.
I had not realised that the B-52 incident had affected the nationals in the way you state ? but perhaps common sense has prevailed and more likely that the insurance has some bearing on this ? it is one thing operating a large model with only a few people present,but to operate relatively unproven models at very large shows with higher risks is a different matter,perhaps a system like the Farnborough airshows whereby the aircraft should have accumalated x number of hours would be better ?
Large models are lovely to see in flight,but the B-52 incident brought with it concerns for public safety when things go horribly wrong.

__________________
'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/