VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-8/8A
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 01-19-2019, 09:08 AM
jlbpropilot jlbpropilot is offline
 
Join Date: Aug 2017
Location: Belmond, IA
Posts: 29
Default

Looks like in the last picture you can see that the rear spar is aft of the slots the ears go through by about 3/16"
Reply With Quote
  #12  
Old 01-19-2019, 11:47 AM
sapeloson's Avatar
sapeloson sapeloson is offline
 
Join Date: Nov 2009
Location: Jesup, GA
Posts: 151
Default Do you have this plans page?

DWG78 is what you need...
__________________
RV-8
Empennage - 95%
Wings - 95%
Fuse - 95%
Finish Kit - 95%
FWF, Wiring and Paint in progress
Garmin IFR by Stein
Lycoming IO-360 (180HP)
MT 3 Blade CS
N84TH / Registered and GA sales tax paid! $@&!;:?)(!
N3159F C-182 @ KJES
Reply With Quote
  #13  
Old 01-19-2019, 12:40 PM
jlbpropilot jlbpropilot is offline
 
Join Date: Aug 2017
Location: Belmond, IA
Posts: 29
Default

The drawing shows the spacers under the front spar, I understand that. My issue is when the bolts are installed vertically which attach the front spar to the fuse, there is about a 3/16" gap between my rear spar and and stab attach bars. My rear spar sits aft which leads me to believe that when the 4 holes drilled in the front spar it must not have been correctly installed. The only solution i can come up with is a spacer between the rear spar and the attach bar to take up the 3/16" space

Last edited by jlbpropilot : 01-19-2019 at 12:51 PM. Reason: new thought
Reply With Quote
  #14  
Old 01-19-2019, 12:48 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,013
Default Drawing 27 and 27A

It is drawing 27 and 27A in my set of drawings, but they are for the older (not match-drilled) fuselage, so the numbering may have changed.

In any case, the rear spar of the horizontal stabilizer is supposed to go behind the vertical bars, but clamp right to them. It appears your previous builder for some reason set up the stabilizer too far far aft.

Have the holes been drilled through the rear spar and vertical bars yet?
-If yes, then it appears the previous builder for some reason decided to shift the stabilizer aft. Strange. Is the incidence angle correct? There are some spacers that need to be inserted temporarily to hold the stabilizer at the right incidence angle while drilling.
-If no, then I wonder why the previous builder drilled the forward holes at this stage.

Lets see if we can brain-storm some fixes for you.

One option for you would be to make a set of shim plates to fit between the vertical bars and the rear spar. This, plus using appropriate length bolts, should be fine. But a few other issues are going to appear down the road because of this. One is the possibility that the elevator horn will interfere with something that limits the 'up' elevator travel. Note that the angle F-812B is made to provide the up elevator stop, and you notch it as needed so that the elevator horn hits it at the correct elevator angle. Shifting the stabilizer aft is going to require a deeper notch into the F-812B. Hopefully the elevator horn won't hit anything else. The next issue is that the joint of the forward fin spar to the forward stabilizer spar is going to be different. The F-681 joiner is going to be shifted aft too, so that it will want to mount to the aft face of the forward fin spar, rather than the forward face as shown on the plans. You will also need to make a different spacer like F-885 to fill any gap, but it is hard to predict where that is all going to fit until you mount the stabilizer and the rear fin spar. The last issue, a minor one, will be that the fiberglass empennage fairing is not going to fit very well. That's OK, they usually do not fit great anyway -- I did some custom fiberglass work to make my fairing fit around and under the stabilizer leading edge, and this fit issue would be resolved then.

Another option might be to replace the components in the fuselage that have been drilled, so that the stabilizer could be mounted in its proper location, shifted 3/16" forward from where it is now. The F-810C angle would not be too difficult to replace. Unfortunately, the outboard holes also go through the upper longeron, F-887. This is a problem. You don't really want to splice a new piece of longeron in place of the old, although that could be done. With a new F-810C angle providing good bolt bearing area, it might be OK to just make a second hole in the longeron. Not generally accepted practice, for sure, and definitely would want to get buy-in from Vans. You would have to be very careful drilling the new hole, because if the drill gets into the old hole at all, it is going to steer the drill wrong. Could put an aluminum plug in the old hole first, that would help. You would end up with two holes through the longeron that are right next to each other, like a figure-8. Again, this is not generally allowed so you would want to discuss it with Vans. The saving detail here is that the hole would go through a new F-810C angle in the proper place and that would hold everything together.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 525 in 9 years (would have flown more this year if not for fire smoke)
also LS-6-15/18 sailplane
VAF donation Jan 2019
Reply With Quote
  #15  
Old 01-19-2019, 01:55 PM
jlbpropilot jlbpropilot is offline
 
Join Date: Aug 2017
Location: Belmond, IA
Posts: 29
Default

Excellent information Steve. You are understanding exactly what I was trying to convey. Yes, all 8 holes are drilled (4 in front spar angle, 4 in rear spar) that attach the stab bars. For whatever reason the horizontal must not have been tight against the mounting bars when the front 4 holes were drilled. No idea if the incidence is correct as of yet. The rear spar holes definitely require the spar to float above the fuse when mounted which is good.

The good news is that when mounted using the 4 bolts in front the vertical stab lines up just fine and i don't see a problem. If Im understanding correctly the front face of the Vertical mounts to the aft face of the horiz stab. In my case this is true.

The stops have already been notched. I simply put a digital level on the elevators when in the neutral position and zeroed out my level. If that is an appropriate way to measure I end up with 26 degrees up and 24 degrees down travel to the stops. This is with the horizontal mounted slightly aft of where it ultimately should have been but with spacers could be safely mounted

Sound correct?
Reply With Quote
  #16  
Old 01-19-2019, 08:09 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,013
Default

My drawing shows the fin spar joiner (F-681) mounting the aft face of the stabilizer spar, and then the fin spar goes on the front face of the joiner, with a spacer. Yours will probably want to have the fin spar behind the joiner, so the front face of the fin spar fits against the joiner, and then the front face of the joiner fits against the aft face of the stabilizer spar. You can put whatever shims you need in there to get everything to mate well.

So it sounds like making some shims to fill the gap between the vertical mounting bars and the forward face of the stabilizer rear spar will solve all your problems as long as the elevator horn doesn't hit anything.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 525 in 9 years (would have flown more this year if not for fire smoke)
also LS-6-15/18 sailplane
VAF donation Jan 2019
Reply With Quote
  #17  
Old 01-19-2019, 11:19 PM
Wunderon's Avatar
Wunderon Wunderon is offline
 
Join Date: Jun 2014
Location: Seattle (Edmonds) and Iowa
Posts: 145
Default

What does the hole location in F-810C-1 look like?
and longeron edge distance ?



for ref, 2005 drawing 78
__________________
Dave Grimmer
RV8 firewall forward
Edmonds WA
paid 2018
Reply With Quote
  #18  
Old 01-20-2019, 05:54 AM
chopperchops chopperchops is offline
 
Join Date: Mar 2007
Location: Brisbane, Queensland, Australia
Posts: 30
Default

I have a QB -8 kit. I had to shim the left vertical bar to fill the gap between it and the rear horiz stab spar, to get the correct alignment. Sterling at Vans had no issues with that. The shim was only 0.032 though.

Out of interest, is your kit a QB?
__________________
Rob Chopin
QB RV8
Wings done, fuse in progress.
Queensland Australia
VAF Dues paid-worth every penny!!!
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 09:16 AM.


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.