B-52 Bomber crashes.

**wonwinglo** · 31-08-2004

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

adzam · 31-08-2004

very sad .

duncan · 31-08-2004

Any reason given ? Pretty close to that house. Tragic end to a supermodel.

**wonwinglo** · 31-08-2004

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.

**Bluewavestudios** · 01-09-2004

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.

**wonwinglo** · 01-09-2004

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 !

**Bluewavestudios** · 02-09-2004

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

**wonwinglo** · 02-09-2004

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...

**wonwinglo** · 02-09-2004

*** 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.

adzam · 09-09-2004

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