B-52 Bomber crashes.

Discussion in 'Planes' started by wonwinglo, Aug 31, 2004.

  1. wonwinglo Scale Model Member

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    Sad news in the modelling world. The big b52, of which we reported
    is no more. Sadly she crashed over this weekend on
    her first downwind leg after take off. The U.S.S.A.F team were displaying at a
    field quite near by, and had elected not to fly due to the adverse
    weather conditions.

    The model was a terrific achievement and I take my hat off to to team
    who built her, as I do to anyone who achieves such a success. Best of
    luck with the next project (which I am sure is already half built!)

    http://www.my87.com/video/b52crash.mpeg
  2. adzam Experimenter Scale Model Member

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    very sad .
  3. duncan one more feather ......! Scale Model Member

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    Any reason given ? Pretty close to that house. Tragic end to a supermodel.
  4. wonwinglo Scale Model Member

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    I am trying to find out more about the crash,understand that it could be investigated by the authorities,these are big models with big potential to do damage on a large scale,just think of the money involved with all of those engines ?
    If I get more info then I will post it here.
  5. Bluewavestudios Guest

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    Whatever the cause, such a shame to see a fine model meet it's demise like that, initial part of the video looked superb. I remember Chris Gold's Model met same fate a few years back, still don't know if he has built another one yet or not.

    Regards.........Mark.
  6. wonwinglo Scale Model Member

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    Chris sold the B-52 after a rebuild,however the electric motors were worn out,I believe it finished up in a model museum ?
    The problem with these large models is that the large wings can act like an antennae if ferrite rings are not used to stop interferance,there is some mention of this in the BMFA handbook.
    Chris certainly is a prolific modeller,he also flew Hawker Hunters and other jet aircraft in the R.A.F .
    Some of his electric designs amaze me that they fly at all with electric ducted fan power,they must be high revving motors hence why the B-52 electrics were well worn !
  7. Bluewavestudios Guest

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    Yes I remember the electric D/F B52's that Chris built but he also did a much larger D/F Version powered by 8 Engines, all I/C engines too...imagine trying to synchronise that lot....!!! I remember seeing the pics in RCM&E when it was under construction...It was Huge...!!! A few pics of the completed article under tests followed in later mags. (Going back a few years now but roughly the same time as he did his BAC Lightning and Tornado.....I remember they were powered by .81 & .90 I/C D/F engines) The Main U/C wheels were those sort you see on baby buggies (thats what he used for them...!!) I remember it crashed on one of it's first few shows.

    Chris did a baby B52 for electric power followed much later by his 12ft span electric D/F Version.

    It was much bigger than these electric D/F ones, (Those baby buggy wheels are 5" diameter and were to scale on the original model that Chris built)................shame there are no pics on the net, I might still have the original mags around somewhere and can scan one in if I can find it...!!

    Regards......Mark
    Last edited by a moderator: Sep 2, 2004
  8. wonwinglo Scale Model Member

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    More on the B-52 Bomber crash.

    Received a note from my good friend Peter Simpson this morning regarding the sad crash of the B-52 Bomber at the weekend,this is what he has to say-

    The Rumour is that only one engine survived. The model was sponsored
    by the jet engine manufacturer as an advert. The pilot was contracted
    to fly the B52 at a set number of shows as part of the deal. Hence he
    would have been under considerable pressure to fly even in the poor
    conditions.

    Here is my analysis for those interested. I was not there and only
    have the video as evidence. There are other theorys out there!

    Stability of a wing caused by Dihedral.
    On an aircraft with Dihedral, in a banked condition the low wing has
    a greater planform area than the high wing, and therefore gives
    greater lift leading to the stabalising effect of lifting the low
    wing. In exactly the same way an aircraft with anhedral is inherently
    unstable as the high wing has more lift than the low wing leading to
    an increase in the bank.On an aircraft of this type what you really
    want is stability, therefore I assume that the only reason that the
    full size B52 aircraft has anhedral is because it needs that castor
    at the end of the wing to support its weight.

    The operation of Ailerons.
    Firstly aircraft roll is a reaction of air being deflected off the
    trailing edge of the aileron.
    Secondly ailerons change the lift characteristics of a wing, so in a
    right hand roll, the left wing aileron goes down, increasing the
    overall angle of attack of the wing and therefore the lift. The right
    aileron goes up and thus decreases the overall angle of attack and
    reduces the lift in the wing.

    In order for the aircraft to roll, one wing must be providing more
    lift than the other. With an anhedral wing in a banked condition the
    low wing offers considerably less lift than the high wing, however in
    order to reduce the bank the lift generated by the low wing must be
    increased and the lift generated by the high wing must be reduced.
    The ailerons are used to achieve this. However the more the angle of
    bank of an anhedral aircraft, the greater the natural differential in
    lift of the wings, therefore the greater the required change in lift
    by the ailerons.

    Conclusion
    The ailerons can only achieve a finite change to the lift
    characteristics of the wing. With an anhedral wing, the greater the
    angle of bank the greater the difference in lift offered by the wing.
    Therefore there must be an angle at which the difference in lift
    generated by the wings exceeds the difference in lift that can be
    generated by the aileron.

    My conclusion is that the model B52 did not stall, it simply exceeded
    this angle of bank, therefore there was no way that any control input
    would correct the bank and the enevitable happened. Given the
    conditions, it is highly likely that turbulance caused the excessive
    bank rather than bad piloting and no pilot, however skillful would
    have been able to retrieve the situatuon. My team were supposed to be
    displaying this weekend, and our aircraft are much more controllable
    and rapid in response than the B52. We elected not to fly due to the
    conditions.

    Thanks Peter for that update,my own observations on this to follow...
  9. wonwinglo Scale Model Member

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    B-52 Bomber crash-More observations.

    *** Thanks for the succint explanation Peter,most interesting,I know
    that this was a model in this case,albeit a very large one, but
    there are a few valuable lessons to be learned here.
    The model obviously exceeded the flight envelope in regards to the
    flight characteristics of the full size B-52 but there have been
    caes in Vietnam where disabled B-52 Stratofortress aircraft have
    encountered severe wing drop at high angles of bank,couple this with
    high angles of attack as you point out with aileron deflection and
    the situation becomes critical,an unfortunate combination of factors
    which could possibly have led to the demise of this model.
    High aspect ratio wings also have known undesirable characteristics
    as regards to flexing and aileron reversal caused by airflow over
    extreme tip portions,glider pilots are all to full aware of this
    problem and steer well clear of getting into trouble with that
    particular flight envelope,in the case of the B-52 one other aspect
    has to be considered and that is the sweep of the wings,whether the
    situation is aggravated in the situation that you mention is
    possible ?
    Annedral can in certain cases increase stability such as on the
    tailplanes of modern jet aircraft where the jet efflux is directly
    in line with same,the designer recognises the need to make the most
    of anything on a jet aircraft that will increase the control respone
    in the aircrafts airflow,propeller driven types are so different in
    as much that we have a wide circular slipstream constantly making
    its way around the fuselage adding that all essential bite on the
    controls,the only down side being the torque of the airscrew trying
    to twist the machine the other way to the rotation of the propeller.
    All these factors add up in the main context of stability at
    unusually high bank situations betweeen jets and piston types,in the
    very early days of all through jet training in the Royal Air Force
    the problems were highlighted whereby relatively low powered types
    such as the Jet Provost were giving pupils a very hard time,control
    lag response did give rise to accidents.
    All of these factors add up and when one considers the 'BUS'
    syndrome (bum in seat)feeling to the aircrafts responses,the model
    situation is even more volatile.
    Very sensible of you to allow yourself to become grounded that day
    Peter.
    There are obvious lessons to be learned here for the future,the B-52 is obviously a tricky subject as a model and needs to be approached with great care.
  10. adzam Experimenter Scale Model Member

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    i don`t know if this is the same aircraft or not , but seems a strange coincidence... click HERE for pics
  11. wonwinglo Scale Model Member

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    B-52 Crash.

    *** 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 ?
  12. Bluewavestudios Guest

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    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_2...mpage_1/key_+B52 crash/anchor/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/upfiles/5808/Mk26062.jpg

    Regards.........Mark.
  13. Wowbagger Guest

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    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.
  14. wonwinglo Scale Model Member

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    B-52 Crash.

    ***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 )
  15. wonwinglo Scale Model Member

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    B-52 Bomber-Part 2

    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.
    Last edited: Sep 12, 2004
  16. duncan one more feather ......! Scale Model Member

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    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.
  17. Wowbagger Guest

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    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!).
  18. Wowbagger Guest

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    They salvaged one engine...

    Attached Files:

  19. Pete1978 Guest

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    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!
  20. wonwinglo Scale Model Member

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    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.

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