Today's Message Index:
----------------------
1. 10:45 AM - Yak-52 elevator failure (Richard Goode)
2. 12:03 PM - 18T torque (Joe Howse)
3. 07:37 PM - Re: Yak-52 elevator failure (Cliff Coy)
Message 1
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| Subject: | Yak-52 elevator failure |
To answer the queries of several people who have written to me directly:
=D8 I have passed on all that I know today ' but it seemed to me that
this is
a critical issue that any sensible owner would want to check on their
own
aircraft.
=D8 I understand from Yakovlev themselves that they will issue a formal
Service Bulletin (AD).
=D8 Again I understand that this will be made out of steel rather than
aluminium alloy.
=D8 However I do not know any more details of when/where the plate
might be
made etc.
=D8 I have no idea if there would be a potential similar problem with
the
18T/50 etc, which have a similar design.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
<http://www.russianaeros.com> www.russianaeros.com
Message 2
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Anyone have a torque chart for the 18
Joe
Message 3
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| Subject: | Re: Yak-52 elevator failure |
*Cracking in this area has been a known issue for many years.
The contributing factors seem to be:
Incorrect elevator cable tension
Incorrect elevator travel
and ~sigh~ abuse of the machinery....
These conditions allow for the elevator counterweight to strike the
horizontal stabilizer and/or up inside the vertical stabilizer. This places
a bending moment between the counterweight arm and the elevator whose
weakest point is exactly as Richard has shown.
If rapid movement to the elevator stop produces a hard knocking slap,
inspect and repair immediately.
I'm sure the change to steel will alleviate any work hardening issues that
the aluminum horns may be developing, but the contributing factors above
will not stop this kind of failure, it'll just move the failure to a
different point- like the counterweight bolts or center elevator bearing.
If nothing else, I'm glad to see the horns are available.
How are you addressing match drilling to each individual counterweight?
Thanks Richard!
Cliff
*
On Fri, Mar 25, 2011 at 13:16, Richard Goode <richard.goode@russianaeros.co
m
> wrote:
> To answer the queries of several people who have written to me directly:
>
>
> =D8 I have passed on all that I know today ' but it seemed to me that
this
> is a critical issue that any sensible owner would want to check on their
own
> aircraft.
>
> =D8 I understand from Yakovlev themselves that they will issue a formal
> Service Bulletin (AD).
>
> =D8 Again I understand that this will be made out of steel rather than
> aluminium alloy.
>
> =D8 However I do not know any more details of when/where the plate might
be
> made etc.
>
> =D8 I have no idea if there would be a potential similar problem with th
e
> 18T/50 etc, which have a similar design.
>
>
> Richard Goode Aerobatics
>
> Rhodds Farm
>
> Lyonshall
>
> Herefordshire
>
> HR5 3LW
>
> United Kingdom
>
>
> Tel: +44 (0) 1544 340120
>
> Fax: +44 (0) 1544 340129
>
> www.russianaeros.com
>
>
> *
>
===========
===========
===========
===========
> *
>
>
--
Clifford Coy
Border Air Ltd.
629 Airport Rd.
Swanton, VT 05488
802-868-2822 TEL
802-868-4465 FAX
Skype: Cliff.Coy
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