Richard,
Nice of you to chime in on this matter, but you did not answer
the mans question. I don't think I quite follow you when you say "It
is a great pity that this simplistic notion still continues". To
what "simplistic notion" were your referring?
I would be interested in knowing what the "number of structural
problems" that emerged actually were. Does anyone (such as yourself)
have a verified list of the actual structual problems that are
supposed to have been occuring on Yak 52's? If so, is there any
independant verification that these problems were truly occuring in
the real world.
I do know the trail that led to Bulletin #107 and from that, I
believe that bulletin 107 is nonsense....written in an attempt to
raise some money at the bureau in those dark days of the early to mid
90's when they had no funding from anybody. If you know different, I
would appreciate hearing about it.
So far as I know, NO Yak 52, with or without the wing attach
and spar carry through modifications mandated by 59 and 60, has
crashed due to structural failure.
Roger Baker
On Aug 29, 2008, at 9:41 AM, Richard Goode wrote:
>
> I see there is another enquiry about how to identify the heavy spar
> on the Yak-52.
> It is a great pity that this simplistic notion still continues.
>
> To confirm:
>
> Yak-52 is a very tough aeroplane but when it began being flown
> hard, a number of structural problems emerged. As they emerged,
> Yakovlev instituted a series of mandatory Service Bulletins to
> allow the aeroplane to continue to fly at the same G limits.
>
> Unfortunately, many aeroplanes have not been modified; some
> logbooks have been falsified etc.
> There are actually 114 Service Bulletins, of which many are trivial.
> Our view is that there are 31 serious structural Bulletins, which
> really should be installed on any 52s doing aerobatics at more than
> (say) 4G.
>
> The list of these important Bulletins is as follows:
>
>
> 9 48 71
> 18 53 72
> 28 54 75
> 34 59 80
> 36 60 82
> 37 62 92
> 38 66 93
> 41 67 99
> 45 69 100
> 47 70 106
> 107
>
> The critical wing Bulletins are:
>
> 59 for stronger wing mountings
> 60 for stronger centre section
> 107 ' external (underneath) spar-strap
>
> 59 and 60 came out together in 1987 and 107 in 1991
> So the practicality is that an aeroplane built after the middle of
> 1991 SHOULD have all SBs incorporated.
>
> Also, any aeroplanes incorporating 107 are almost certainly
> incorporating all earlier Bulletins.
>
> 107 can be identified by being a metal plate, about 4=92 long, bolted
> under the wing to the main spar, but proud of the under-wing surface.
>
>
> Richard Goode Aerobatics
> Rhodds Farm
> Lyonshall
> Hereford
> HR5 3LW
> United Kingdom
>
> Tel: +44 (0) 1544 340120
> Fax: +44 (0) 1544 340129
> www.russianaeros.com
>
>
