I like to call the Vertical Stabilizer the "VF"
(vertical fin). The processes
are much the same as the HS and I'm sure many builders construct both
assemblies simultaneously. The measurements in the plans for the VF are
pretty straight forward. I gathered up the channel and the doubler for
the rear spar and laid them out. I measured the doubler, positioned it
in the spar channel and drilled it to the table/beam.
Once you have the two parts drilled @ 40 and then
clekoed together, you start adding the pivot brackets that the rudder
will swing on. The process is the same as with the HS, except that 2 of
the 3 bracket's holes are pre drilled for you. That doesn't make lining
up the brackets super easy, but it sure helps. Clamping them to hold
them steady during drilling is not easy. Time to by more tools
The bottom 22 rivets of the VF-008 assy must be FLUSH rivets.
The forward face of the rear spar mates flush against the #12
bulkhead, so all the rivets below the marks that are for "drilled in
assy with fuselage" in the manual MUST be flush rivets.
That's about as far as I can get with the rear spar
for now. Next, on to the front spar. It has a new big doubler added for
the EVO edition F1. That makes the process a little more time
consuming, but this part is pretty easy initially. You mark the holes
for drilling on the little (old) doubler per plans. Then you sandwich
the spar channel between the doublers. You mark the centers of each
piece to help align them, check the position of the fingers to the edge
of the spar channel, clamp it tight, and start drilling! #40 to
start with, of course!
The pic above shows the doubler/channel/doubler
sandwich. It's easy to work on this clamped and sitting off the edge.
Once you've drilled, clekoed, drilled, clekoed, etc.,
you can remove the clamp and finish drilling all the holes in the
I had a question about the spacing on the undrilled
part of the big (hidden) EVO doubler underneath, so I emailed Mark.
I'll stop here for now and resume the VF when I hear back.
Above is the inside of the VF front spar channel with
the EVO (big, new) spar clekoed in position. You may be able to see
that up on the two big fingers there is a lot of room for drilling
rivets. That's the unknown. All the other doublers have used 7/8 or 1
inch. Either will work, but I want to "get it from the main line,
I heard the good word and continued working on the VF.
I went ahead and finished the front spar first. Simple countersink the
new big doubler for flush rivets, and rivet the whole thing up. Kinda
simple and fun.
Below is what it looks like completed.
You can see the 5 flush rivets in a cross pattern at
the bottom of the rear side of the front spar in the vertical fin.
I was also able to complete the VF rear spar with all
brackets (hopefully) in alignment. I went ahead and primed this part
because it will be open to the weather.
Vertical Stabilizer Skeleton
I gathered up the parts, and I was happy to lay all
the parts together to see what the VF skeleton looks like. Below is a
picture of the VF parts loosely together.
After a big lunch and a huge nap, I decided to, as
Mark Frederick says "Carry On!". I went ahead and removed the HS from
the tail jig, and repositioned the brackets to construct the Vertical
Fin. I pinned the VF rear spar by the pivot brackets to the tail
jig brackets (Avery). I drilled the upright for a stabilizing 1/4
threaded rod, and squared up the tip rib using a speed square, and
verified everything with my digital level. All this is per plans, and
the measurements are very well laid out.
The plans say to make a bracket to position the
forward spar. I decided to use some scrap aluminum plate and left over
threaded rod. I drilled the 1/4 holes in the top member of the tail
jig, and ran the rod down so it would sit between the bottom end of the
spar and the little tip rib. After getting the bracket to sit square on
the end of the fwd spar, I clamped it down. I made measurements from
the plans and started aligning all of the VF parts to get ready to
assemble the skeleton. That's where I stopped. 10 building hours today,
and I'm pooped!
Setting up the skeleton on the aluminum H frame jig is
pretty straight forward. Most of the time I spend measuring, measuring,
measuring! I used cleko clamps and got all of the parts in position
and marked them. Then of course, double checked all my measurements.
Then I started drilling and immediately clekoing each hole as I went. I
started at the spar and worked my way outward, rechecking the
measurements as I went.
After everything was drilled and clekoed to the small
size, I drilled it up, clekoed again, and checked my measurements as I
went. So far so good.
I took everything off of the jig and deburred it. Got
everything ready to rivet. BTW, I did not have to smooth the lightning
holes in the ribs. They were already primed and smoothed for me!
Nice bonus in the EVO!
I put everything back on the jig and riveted it. This
may have been a mistake, but it turned out OK. I had to drill out
several offset rivets, and the oblonged a bit. Had I reversed the
rivets and put the factory head on the thick side, and the shop head on
the rib side, the results would have been much easier and better.
Probably would not have had to re rivet anything. That offset cup rivet
set was a bitch to work with. I'll make every effort to avoid that from
**TIP: If you want to get a really pretty skin on your F1 (or any
riveted surface), I highly recommend that once you get the skin drilled
and clekoed in place that you GLUE or BOND the skins down just prior to
riveting. Pick the side you want the prettiest and glue that side to
the skeleton and cleko it for about 24 hours. On a side that you may
need to leave open until very last, you can still glue it prior to
assembly and get a better than average looking surface. Just wax or use
releasing agent on the mating surface of the skin and glue it down. The
next morning, just remove the clekos and pop the skin free. When you go
back to rivet it down, you will still get a better surface than if you
just bang rivets in bare metal parts. I'm kind of heavy handed and it
shows. I have puckers and deformations that aren't particularly pretty.
I wish I would have done this trick from the start.
Once everything was riveted together, I checked the
measurements again. Then I marked the centerlines on the flanges and
drew extended centerlines on the H-frame jig. I grabbed the skin from
the parts pile and laid it over the skeleton.
The plans are not very clear at this point, although
the measurements on the diagram are fairly complete. There is no
explanation on where to butt the skin, or whether or not anything needs
to be trimmed prior to riveting. I guess we are just to ASSUME, or
inherently know how to proceed. I read over the HS section and really
didn't get any insight.
Finally, an email from Mark F. clarified that you are
supposed to set the skin flush with the root rib flange. Then you are
supposed to make the leading edge tip fit 25 3/4 inches from the spar
doubler. I had a hard time getting to this measurement. I think my
front spar was a skosh to high, which made the tip rib up to high and
therefore the tip of the leading edge too high.
In order to correct this, I got some PVC pipe, jammed
it inside the leading edge in the bend of the VF skin, and bent it
out as much as practical. I got the measurement very close. Mark
sez the only problem I should have with this is that the empennage
fairing may have to be tweaked a bit. Everyone tells me that is the
case anyway, so I don't think I'm out that much.
NOTE: If you
use too small a diameter pipe to close the skins, you can get a rather
sharp leading edge. This can affects the way the skin sits on the ribs.
You actually will want a more blunt Leading Edge so that the
skins will sit back along the frame better. As it turned out, since I
have such an acute angle at my LE, the skins did not sit back quite as
far, and I ended up a little short at the Trailing Edge. So I ended up
with more gap between the skin and my control surfaces.
I placed the skin back on the VF frame and clamped it
in several places at the root and at the top (which on the jig means
along both sides, since the piece is being worked on along it's side).
Then I ripped a couple boards down to 3/4x2x40, drilled for 1/4
threaded rod. I cut several 8 and 10 inch pieces of rod and bolted the
boards over the skin and skeleton. I double checked my measurements and
then transfered the extended centerline drawings onto the skin.
When I measured the centerlines of the flanges, I used
1/2 of the 3/4 inch width as a rule. So the centers are 3/8 from the
outer edge of the flanges. Looking at some of the parts, I don't like
how close that measurement is to rivets and doublers, so when I drill
the holes, I will try to err (fudge) to the outside of the flange.
Maybe get closer to 5/16 on the holes. Since I have never done this
before, and don't have near the guidance I need, a lot of this is guess
work. I hope it works. If not, I can always buy new parts and do it
The vertical centerlines are easy to scribe. The
horizontal line at angles are a bit tougher. After much consideration,
not wanting to slide the skin any, I clamped the skin/frame side ends
tightly and loosened the boards a bit. Just enough to slide in my 4
foot metal rule.
Now that I have the skin where I want it, I have the
centerlines transfered, I have to plan some drilling. Skin rivet
spacing calls for 1 1/4 optimal. Well, I measured between the primary
drill/connection points of the skin and frame, and of course none of
the measurement come out in easy 1 1/4 increments. This is where a "fan
spacer" comes into play. I didn't think I would need one, so I didn't
buy one when I got my tools. Well, was I wrong. I could have used it
several times already, and for the skins, it's going to be crucial.
Fortunately, my fellow builder buddy (RV6) Bruce Dallman is going to
lend me his for a while. I'll be going to OSHKOSH next week, and I'll
pick up one of my own. I'd sure like to have that VF skin attached
before I go up to the show.
You can get along without the fan spacer, and just
make close guesstimates with a ruler. I actually found the fan spacer
easy and quick to use. That's probably much due to the fact that I'm a
rookie at building anything. I think the fan spacer is a nifty little
gadget, and I think I'll get lots of use and considerable help using
Drilling on the VF skin was pretty straight forward. I
clamped everything down, checked the measurements again and got out my
air drill. I started at the bottom and did the vertical rivet lines
along the ribs first (these are horizontal in real life). I drilled the
key "corner" holes at the junctions of ribs and spars. Then I used the
handy large sized fan spacer and clekoed it in these corners, making
sure the spacing was about 1 1/4 inch or less. I then drilled #40 from
the root rib, then the short center rib, then the top rib on one side.
Then I duplicated the action on the other side of the fin.
After having all the verticals clekoed, I was able to
remove the "strapping" boards and drill the horizontal line angles.
Again, using the fan spacer in the key corners to lay out the nominal 1
1/4 inch measurements.
Looking through the plans, I couldn't find anywhere
that describes which rivets are supposed to be used on the VF or the HS
skins. I suspect they are to be flush "#3" rivets of varying length,
and either through 43.13 or intuition we builders are expected to know
it. Since the EVO tail is heavier duty, I'm not sure if we are supposed
to use OOPS rivets like up on the fuselage, or "#4" rivets like on the
cowl. Since Mark snuck off early to Airventure, I'll have to confirm
other sources that might have specific info for the EVO tail. I
don't know if the skins are thicker, or if the EVO tail just has extra
doublers. Therefore I am clueless as how to proceed. I guess I'll
switch over to completing the HS skeleton until I can talk to Mark. Or
maybe I'll just go flying instead... Drat! :-)
Before removing the clekoes and the skin, I measured
the cut off marks for the rudder side of the VF. My 3in1
shear/bending/brake is only 30 inches wide, and I need 35, So I have to
lean on my buddy Bruce again to use the local university's equipment.
It's good to have talented friends with nice equipment and tools!
I could just take a pair of hand shears and cut this
piece. I'll probably have to fine trim it anyway. But Mark F. sez that
a bench type shear is what he uses and it gets the cut very nice and
very close. So I think I'll give it a try. It's a little out of my way,
but hopefully the results will be worth the little trip into
town. Once the VF skin is trimmed for the rudder, I'll be ready
to debur and cs/dimple everything and rivet the skin on the skeleton.
I took the skin to my buddies Bruce and Mark at the
university and we cut the aft edges down. Now it's time to debur,
dimple and countersink the frame and skin. That process went easier
than I thought it would. I used my pneumatic squeezer on all of the
frame, except where I could not get access or there were overlapped
junctions. I used the C frame on the skin.
Unfortunately, on the third dimple, the skin jumped
up, and I punched an oblong dent in the skin. It was not pretty, and I
was pissed. I repaired the dent as best I could and moved on. The rest
of the skin dimpled without incident and I was very pleased overall
with the results.
The pic above is me with the finished Vertical
Stabilizer. I'm hunched over to get a timed picture. The camera
was sitting on the H frame.
Unfortunately, on the FIRST RIVET, I slipped the rivet
gun and dented the skin again. It put a couple pretty deep smileys in
skin. And later on, I slid off again and wanged the skin again. Very
frustrated, I stopped working, jumped on my motorcycle and went to meet
a buddy of mine for a beer. Sometimes you just have to know when to
After several hours and a few beers, I came back
and looked at the damage. It did not look any better, as you might
expect. I decided to go ahead and finish the whole VF anyway. I needed
practice, and since the part was possibly ruined, I had nothing to lose
but some rivets (and lots of time and money).
I could have stopped where I was and drilled out the
rivets which I had already set, got a new skin, back drilled the whole
thing and reskinned it. But I figured the chances of me getting it right
by back drilling a new skin was not good, so it's going to be all or
none. An expensive little proposition if I have to start the entire
VF from scratch.
Now I have a decision to make. Do I start THE ENTIRE
VF over, or do I do some bodywork on the skin. One side turned out
perfectly fine. That was the "closed' side I did second. I though it
would be harder, but it was actually easier for me than the first side.
It's time to go to AirVenture at Oshkosh, so the F1
building is going on the back burner for a while. When I get back, I'll
evaluate the finished VF again, and begin work on the Horizontal
I scuffed the surface of the dings, and then I cleaned
it up nicely. After that, I spread some polyester "icing" to fill the
skin wangs. I think they filled in well, I'm not going to the
trouble and expense to start over (yet). But you can bet I'll be a
lot more careful the next time. After I finish the whole plane, I may
come back and make another VF.
Later on when the rudder was nearly complete, I decided it
time to cut the notch in the VF top where the counterbalance swings
through. I measured per plans and took a dremmel tool and a cut off
wheel and cut the skin just short of size. I'll do the final filing
when the rudder is fitted.
Now that the Vertical Stabilizer is constructed (far from finished), it
goes in to storage. I'll work on it again when I install it on the
airframe. That happens after the Horizontal Stabilizer is installed.
Vertical Fin Installation
Now that the HS is trued as best I can to the fuselage and bolted down,
it's time to tackle the Vertical Stabilizer. First thing to do is
to get out that dusty old HS-015 trapezoid looking thing from last
year. I brought it out, and set it behind the HS forward spar
with the "tongue" facing aft. I put an .032 shim under it to prop it
up. I centered it up and carefully drilled the 6 center most holes ( I
had pre drilled the 6 holes per factory locations, then matched them on
the spar). Turns out that I had to displace the lower outside corner
holes because of rivet locations. No big deal, they only offset about
.5 inches. I used some AN3 hardware and temporarily bolted that
puppy in place.
Next thing to do is to set the tail spring weldment to position. I just
went ahead and drilled a centered hole about 1.25 above the machine
hole. I drilled it up per plans and cs'd it for a ss #8 screw. I went
ahead and used a ss stop nut behind it and cranked it down tight.
Now for that big green fin. I removed the rudder and caps and
brought the VF to the back on my plane. DANG IT! My ceiling was
too low. I had to move the plane a little and then take out one of the
drop ceiling panels to get the VF to position. WHEW! I actually
never thought I'd be able to put that on with the ship still leveled!
The plans are right. You have to trim the lower flange of the aft
rudder spar to get it down to position. I actually had to take off
about 1 inch. I went ahead and drilled the machine hole to #30 on the
VF spar. I already had a bronze cleko in the machine hole on the ship
from a long time ago. Now the tricky part.
My fuse is still level. My HS is set. Now to get the vertical of
the VF set up. Instead of the string method, I again used my trusty
digital level. I conferred with Mark and he agreed that if the
level measurements of each side of the VF spar (level set over the skin
along the spar) that the VF would indeed be level. He did mention not
to forget that you have to be concerned about the offset of the LE on
the VF as well. That comes after getting the vertical under control.
I covered the turtle deck with extra plastic and set a sponge under the
LE of the VF. Rather not have the skin divoted there. Carefully I
set the VF up to position and aligned the machine holes together.
Then I clekoed the parts together. I used a cheap spring camp to
hold up one side of the VF against the emp. The fin wanted to lean to
the left a bunch. I went back and trimmed the spar a bit more (up
to an inch) and also wallered out the cleko hole a bit to scoot the
bottom of the VF spar to the center of the #12 bulkhead and TS
weldment. This helped get the vertical alignment closer, too.
Man, is there some twist in this thing or what? See how much the VF is
offset to the right? Had to email the pic to Mark to verify that the VF
can be wonky like that compared to the #12 bulkhead.
I checked the level of the fuse again, and the level of the HS (the
level fits under the VF ! ) again, and tweaked the VF until
it was even and ready to match drill. Now comes the hardest part.
Making sure I don't move the thing when I drill it. The cheap spring
clamp will help, but I'm going to have to tip toe through this process
to keep this all straight.
The VF rear spar needed to go to the left a little bit more. I shimmed
and clamped the side and bottom of the rear spar onto the #12 bulkhead
and then removed the cleko. I drilled the hole up for an AN4-6 bolt and
nutted it in. Checked the measurements again and prepared to drill the
upper AN4 bolt holes. That one is a little tricky. The Tail Spring
weldment now has a thick lip to it. And the upper edge is not very far
above the lower edge of the hinge bracket. So positioning those two
holes is difficult. And if you go by the pic in the manual, you will be
too far outboard. The bolts need to go a little farther inboard,
perhaps 1/8 to 1/4 inch on each side. That way you can get a wrench on
the nut and not interfere with the lip of the TS weldment.
Now you can really see how twisted the emp is. Also note the shiny new
rivets in the area above the lower hinge. Yes, I didn't use flush
rivets there when I made this thing over a year ago. I got to drill out
and replace 12 rivets. No big deal, just didn't like wasting the time
to do it. Had to, though, because the VF lower 22 rivets sit flush
against the #12 bulkhead.
I rechecked my measurements. My VF measures at precisely 88.7 degrees on each side. That's how I know it's vertical.
Before moving on to align the LE of the VF, I have to make a 1x1x.125
angle bracket to attach the mid area at the VF spar to the empennage
deck. That's relatively simple. Just have to make sure to center the
bolt holes over the emp longerons and put two AN3's in there. Then
drill for two AN3's through the VF spar. Easy peasy.
At this point it is recommended that you mark the emp deck panel
and cut it back to the angle bracket just fabricated and bolted to
position. You have to cut the panel out in front of the angle bracket
to increase the elevator horn travel in this area. You might even need
to go back and cut the angle bracket back some as well.
Next step is to align the leading edge. I could attach the upper brace
angle (sits on top of the emp deck), but I thought it made sense to
align the rear, then front, then use the angle brace to help maintain
the VF's position. Probably doesn't matter that much, but that's the
way I'm proceeding.
The string method described in the manual works pretty well in this
instance, and that is how I will set the VF leading edge. After that,
I'll drill the forward VF spar to the HS-015 and cleko it down.
At rest, my LE was about 1/16 to 1/8 to the left. It was easy to scoot
the VF's LE to the right and line it up. The tricky part will be
clamping and drilling it to that position. Especially considering I need
about an .040 shim between the VF and the HS at the front spar. I
suppose I could take those stir sticks out and let the LE drop down a
bit to let the spar parts rest closer together and avoid the shim?
Maybe? DOH, better ask Mark. Think I'll quit there and come
back to it again tomorrow.
Shim the HS-015
The ruler on my pink string at the LE of the VF miraculously had not
moved overnight. Time to start thinking about locking this baby down.
Alas, there is a HUGE gap between the VF spar and the HS-015 bracket.
Mark said definitely shim it. SHIM is an understatement. I put 4 pieces
of .032 under there and still had slop. Mark suggested that I use
hardware store 1/8 inch aluminum. I thought I had some, but what I had
was more like 1/4". So I went with it.
Mark suggested that something was not quite right since I had such a
large gap at the HS15/VF spar junction. Other than the factory bend in
the HS15 being wrong or my mounting of the HS15 to the HS spar
being too low, I can't imagine what I might have done to have such
a large gap. Something is off somewhere. But it works.
I proposed to rivet a spacer onto the tongue of the HS-015 before
drilling it to the VF forward spar. I cut a piece of aluminum 2
3/8 x 3 1/2 inches and prepared to mate it to the HS15. I used the same
drilling pattern used on the lower end of the VF spar, a cross pattern
that leaves 4 "corners" open for the four attach bolts. I drilled it
40, then 30, cs and deburred it and then squeezed 5 each 4-8 flush
rivets on there. Remember, the forward face has to be a flush mating
surface. Using 5 sized 4 rivets is overkill, but I liked the
pattern, and I can always squeeze #4's much better than those dinky
#3's. Ham handed, YES!
The HS15 bolted back up and I rechecked my measurements. I ran a piece
of floss through the rudder brackets per Mark's suggestion to make sure
I didn't twist anything. So far, so good.
Set the Leading Edge
With the Rear Spar of the Vertical Fin bolted to position, the Leading
Edge of the VF is still free to move. It will not only go side to side,
but you can tip it up and down. You can't move it much, but just enough
to get the Leading Edge centered with the long axis of the airframe.
When I was flossing my brackets, I notices my LE measuring pink string
was getting in the way, so I untied it, and moved the angle brackets,
clamps and string above the upper rudder bracket. That made it easy to
check the rudder bracket holes with the floss, AND gave me an
opportunity to check the LE from a different perspective.
I wasn't using those centering things that go in the bracket holes.
Instead, I just moved the tied down floss (Glide floss, btw, great
stuff, but VERY slippery Gortex/Teflon filament) around to three
locations in the holes. Essentially, I used my fingers at the top and
bottom brackets and shoved the floss against different locations at the
holes. IE, I shoved it to the back, the front, and at least one side.
When I did this, I observed where the floss was in the middle bracket.
Every time, the floss was at the same position on the bracket holes as
the upper and lower brackets. Therefore, I am confident that they are
When I was doubletriplequadrouple checking the VF spar and HS15
position, I noticed that the rivet patterns did not line up. That means
I am either going to have 2 bolts REAL close to a pair of rivets, or I
was going to compromise the ED at the top of the HS15. The manual
suggests 3/8 inch spacing from the edge. I am going to try to get 1/2
if I can. The VF rivets and the top edge of the HS-015 bracket will
have to determine the location of two of the bolts. The wood
spacer I had at the tip of the LE of the VF came out, and I
scooted the VF downward and forward. I can only go so far. I rechecked
the rudder brackets and they were still in alignment. So far so good.
Now what I propose is to TRIM the tip of the LE of the VF and scoot the
front of the VF down as far as I can without taking anything out of
whack. That ain't gonna be much, but it feels like the tip moves fairly
easily. That's a good sign.
My dremel made quick work of the tip of the nose of the VF Leading
Edge. I spent some time cleaning it up with a file, trying to follow
the contour of the turtledeck. I cut a little more than 3/16 or so out
of there, and then scooted the fin downward. A quick check of the
rudder bracket holes and things are still OK. I went back and checked
the centering of the LE and that looked good. While I was at it, I
changed how I had my pink centering string set up. Since it runs over
the canopy bubble, I went ahead and ran the strings and taped them down
together. My center screw in the windshield bow is a skosh off center,
so I compensated for this. I moved the string to what I thought was on
center, then measured from the string to the rear top corner of the
wing spar holes. Now I know the ship is asymmetrical when it's built
(so much for factory jigging) and even the bubble probably isn't
symmetrical. But I had to pick SOME common location on the sides that I
thought would be even. That's my best guess. From there, I went back
and checked the LE centering again.
I clamped the VF spar and the HS15 together with a quick clamp and
scooted the VF around a little. I double checked all the measurements
again. It's good to go. By trimming the nose of the VF and moving
the whole thing down, I was able to get the rivet that shows in the 2nd
pic above to be hidden below the edge of the HS15 and it's spacer. NOW
I have LOTS of room to put the 4 bolts in and maintain ED and clearance
from rivets. Hope it all works down the road!
Notice again how the rivet that was visible above the HS-015 is now
below the upper edge. The rivets still don't line up between the tow
parts, but now I have enough room to easily drill the parts to
position. That will finally set the incidence of the Leading Edge of
the Vertical Fin and complete it's installation. That of course by far
does NOT complete installation of the tail. After the VF front spar is
bolted to the HS-015, I have to begin installation of the control
surfaces, their mechanisms and alignment.
Drilling these two parts together was not much fun. Not terribly
difficult, but a pain. I used an angle drill in my air drill to get the
holes up to #30 of course clekoing as I went. Then each hole right up
to an AN3-7 bolt and tightened down. My bolt pattern didn't turn
out as pretty as I would have liked, but it's functional. I used 1/2
inch instead of the 3/8 suggested in the manual. That way, just in case
I have to reposition and drill up to an AN4, I still have plenty of
meat all around.
Part of the misalignment of the bolts is the wonky camera angle. But
sure enough, that upper right bolt is a little down and in. Better that
that up and out.
I consider this a very good way to end 2005. It looks like I have an
airplane coming together. There may be light at the end of this
HAPPY NEW YEAR!!!!!!!!!!!!!!!
Now that the Vertical and Horizontal Stabilizers are set, it's time to Hang the Rudder !