VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.






VAF on Twitter:
@VansAirForceNet


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #131  
Old 08-23-2022, 09:56 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 3,372
Default

Quote:
Originally Posted by Snowflake View Post
While the vertical stabs have failed in these accidents, it's happened after other items failed first (ie. the rudder). The forward spar on the vertical stab is a red herring. Reinforcing the attach point of the vertical stab as AntiSplat suggests just creates stress concentrations elsewhere.
I agree with this. In at least one of the two cases, the attach bracket that Anti-splat replaces with a stainless steel one was NOT the final failure point either. The fwd fin spar actually tore right above the attach bracket. I think BillL has a really good photo showing this.

Although this point was not the initial failure (other stuff broke first), the stiffness at this point may contribute to the flutter boundary. In Rockets, and several Reno-racing RVs, the fwd fin spar gets a doubler that runs part way up (to the middle rib IIRC) which stiffens the fin in torsion (and also somewhat in bending). With this added thickness from the standard fin spar plus the doubler, a thicker attach bracket should also be used. The rear fin spar also gets additional strengthening/stiffening.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet" Flying since Sept. 2009
Hobbs 725
also
1/4 share in 1959 C-182B (tow plane)
LS6-15/18W sailplane SOLD
bought my old LS6-A back!!
VAF donation Dec 2022
Reply With Quote
  #132  
Old 08-23-2022, 10:32 PM
sailsunfurled sailsunfurled is offline
 
Join Date: Oct 2021
Location: Gulf Breeze,FL
Posts: 30
Default

Did the pre 2002 -7 come standard with -8 rudder?
__________________
RV-7A in progress
2022 Dues Paid
Reply With Quote
  #133  
Old 08-23-2022, 10:54 PM
jask jask is offline
 
Join Date: Feb 2018
Location: Ramona, CA
Posts: 292
Default

Quote:
Originally Posted by sailsunfurled View Post
Did the pre 2002 -7 come standard with -8 rudder?
Yes, it came with the 8 rudder.
__________________
RV-7 builder Ramona, CA.
Free prop balancing for Vanís owners.
RV-6A N665CM
Reply With Quote
  #134  
Old 08-23-2022, 11:21 PM
sailsunfurled sailsunfurled is offline
 
Join Date: Oct 2021
Location: Gulf Breeze,FL
Posts: 30
Default

Quote:
Originally Posted by jask View Post
Yes, it came with the 8 rudder.
Thanks for verifying what I thought I read sometime ago.

I took over a -7 build this past year (wings and tail partially built). It had the original rudder, 2001 was the year of the tail kit order. While waiting for my fuselage kit, ordered Nov. 2021, I requested the free larger rudder mentioned in Vanís service bulletin to make some movement on my build.

I am in the middle of building the new rudder when I noticed this thread. I will finish the larger rudder for the practice and to hone my skills but install the original ď8Ē rudder.

Informative thread and reading, thanks all for your contributions and view points.
__________________
RV-7A in progress
2022 Dues Paid
Reply With Quote
  #135  
Old 08-24-2022, 12:05 AM
jask jask is offline
 
Join Date: Feb 2018
Location: Ramona, CA
Posts: 292
Default

Quote:
Originally Posted by sailsunfurled View Post
Thanks for verifying what I thought I read sometime ago.


I am in the middle of building the new rudder when I noticed this thread. I will finish the larger rudder for the practice and to hone my skills but install the original ď8Ē rudder.
Good plan.
__________________
RV-7 builder Ramona, CA.
Free prop balancing for Vanís owners.
RV-6A N665CM
Reply With Quote
  #136  
Old 08-24-2022, 09:27 AM
mburch's Avatar
mburch mburch is offline
 
Join Date: Feb 2005
Location: Oregon
Posts: 1,518
Default

Quote:
Originally Posted by Thermos View Post
Although the RV-10 and -14 rudders still have riveted trailing edges, the internal structure is different from that in the-7/9. Stiffeners are tied to the rudder spar with shear clips, and the stiffeners themselves are much more robust - the horizontal flanges are joined to their mates on the opposite side with a rivet about halfway down the rudder chord. Also, the counterweight skin is integral to the rudder skin and not riveted on as with the -7/9.

My professional flight test work has only dealt with structures and flutter at a conversational level, but my sense is that these changes make the rudder quite a bit stiffer. Only Van's can say whether those changes were remedies for a weakness in the -7/9 rudder design, or if they were done for another reason.
This is a thread that seems worth pulling on. The numbering of the individual components that comprise the RV-14 rudder are similar enough to the corresponding RV-7 rudder parts that it leads me to think that an RV-14 rudder ought to bolt right on to an RV-7 VS. Assuming that's true, it would be interesting to explore why two in-production aircraft designs use rudders that are the same external size but have different parts and internal structure... especially considering that there haven't been any known in-flight breakups of RV-14s
__________________
Matt Burch
RV-7 (last 90%)
http://www.rv7blog.com

Any opinions expressed in this message are my own and not those of my employer.

Last edited by mburch : 08-24-2022 at 09:44 AM.
Reply With Quote
  #137  
Old 08-24-2022, 10:48 AM
wirejock's Avatar
wirejock wirejock is online now
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,879
Default Vans

14 pages of comments.
Numerous posts about changing Vans design or components.
Did I miss a Vans comment?
Seems like they would have something to add.
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #138  
Old 08-24-2022, 11:04 AM
airguy's Avatar
airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 6,090
Default

Quote:
Originally Posted by wirejock View Post
14 pages of comments.
Numerous posts about changing Vans design or components.
Did I miss a Vans comment?
Seems like they would have something to add.
If there were something noteworthy to add, yes.

So far this is nothing but conjecture that "something is wrong" - but it's all based on pilots exceeding the published limits of the airplane. Vans will most likely not make any comment at all on accidents where the pilot exceeded the limits of the airplane - the cause of the problem there is obvious. Don't do that.

Is there any evidence at all that shows a failure while WITHIN the published limits of the airplane? Did I miss something?
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2023 dues paid
N16GN flying 1,250 hrs and counting on 91E10; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
Repeat Offender - 10 empennage in process.
Reply With Quote
  #139  
Old 08-24-2022, 07:03 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Southwest, USA
Posts: 2,607
Default Before we leave this topic

In my model airplane days, I was always trying to get my control surfaces stiffer for no added mass. I found that offsetting the tail ribs so the were not parallel increase the stiffness immensely with very little weight gain. When I started playing with real airplanes, I was surprised to see all the tail surfaces ribs running parallel based on what I “knew” from models. Perhaps the analysis tools are better now and non-parallel ribs can be assessed for if they provide greater stiffness with only minimal weight increase.

OK I am done with this topic, you may close the thread now. Because it is all about me anyway.
__________________
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Dues paid 2023, worth every penny

RV9A- Status:
98% done, 2% left to go
To Go: wing mounting, engine baffles, wing tips, move to airport
www.pilotjohnsrv9.blogspot.com
Reply With Quote
  #140  
Old 08-24-2022, 08:02 PM
wirejock's Avatar
wirejock wirejock is online now
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,879
Default Speculation

Quote:
Originally Posted by airguy View Post
<snip>
Did I miss something?
Nope. You said it. I was trying to say that without my usual obnoxiois opinion. Thx
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:05 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.