Fitting a Firewall

So we have finally far enough to try fitting the firewall to the front.  I had already clecoed the firewall together (not shown), so fitting it up is pretty straight forward.

I began by clamping the firewall in place with wood blocks an C-clamps.  It took a lot of adjusting to get it straight.

Here is the firewall clecoed in position.  If I wasn’t working in a crowded shop, I would probably have to make airplane noises at this point!

Here is a closer view of the c-clamps with the wood blocks – no clecos yet.

Now we have clecos!  Note the board across the frame.  This was used to ensure the fuselage is straight, because I still am missing some bracing in the front of the nose, and the whole thing can be twisted pretty easily.

Anyhow, this is a boat makers trick.  I used the board on the front of the fuselage, and clocked it against the horizontal stabilizer (on a boat, you use two boards) to ensure there is no twist.  Note the prop blocks under the right corner, which were used to ensure very near alignment.  Call it a very primitive jig.   At this point, I have managed to push all the existing holes on the motor mounts into the firewall and re-usable framing and clecoed them in place.

Here you can see the angle brace on the left, and it is already drilled – as it is being re-used.  On the far side, I am more or less duplicating the pattern, using a rivet fan.  The fan won’t fit into the space in the normal manner, as the structure would get in the way – but it isn’t a problem.  I’m just skipping every other rivet spot on the fan, and that makes it all fit.

Here’s one of the new undrilled weldaments.  At this point, it is pretty well set all except on the bottom.  That will come after I remover the firewall.

Speaking of Wedaments, lets re-visit the ones that I need to replace on the top.

Here is the damaged one removed, and you can see the weld starting to crack.  I’m definitely happy to be replacing this.  All of the holes on this one have been duplicated in the structure and firewall, so it is pretty easy to fit the new one in its place.

And here is the new one next to the old one.  Note how much more heavy duty the new one is.  Its made of three pieces instead of two, and the plate is about doubly thick by comparison.

New motor mount going in.  I used C-clamps to pull it tightly into the corner of the longeron.  Then on to drilling and riveting to the longeron, followed up with drilling and clecoing to the firewall.  At this point, I am starting to run low on clecos.

Holes pushed through the firewall and structure.  Other side is similar.

While I’m at it, lets get that left front skin done.  This is pretty easy, as the old one straightens well enough to make a good template.  All the good quality holes can be drilled in to the new skin, and any that is wallered out will be drilled into the skin from the inside after the skin is clecoed onto the aircraft.

Cutting on the lines around the edges of the skin.  I actually snapped this picture to illustrate why I like offset snips – note that I can cut in a straight line without slicing my hand on the freshly cut edges.  Also, look closely at this photo, as you can see that I can only count to 4 on this hand.

Here is the unadjusted skin, clecoed onto the front.  I’ll play with it a bit to get it to fit smoother.  Note that there are no holes on the front where this would rivet to the firewall.  There is no reason to match any rivets where the other parts don’t fit against pre-drilled parts.  I’ll drill both sides of this seam at the same time.

Also – a brief rant.  Note that half of the plastic is missing on the side.  Wicks aircraft sold me this skin, and I didn’t notice it was missing almost half the plastic on one side until I got it home.  Bleh!

RV4 – Out with the Old, In with the New

Its been quite a while since I have made an update, and I have a long way to go on this post.  While going over the aircraft, I noticed a small skin ripple on the right side near the back of the passenger seat.  I also had a pretty good ripple in the same skin forward of this portion.  So, I determined that that skin had to come off.

I stripped the aircraft fuselage, and got it set up on a table in the sheet metal area so I could begin serious work.  the first order of business was setting it on its side and drilling off  the belly – which extends all the way to the rear of the passenger area.

I’m finally starting to get a good enough idea as to what needs done to start ordering parts.  I plan to splice the formers in F404 – the spar mount area – simply because there is so much drilling and realigning that would have to be done to replace them.  (NOTE  – I changed my mind on this later – but I get ahead of myself.)  Speaking of parts, I was able to find a used engine mount and landing gear legs for $250 plus shipping.  They are shown below.  They will need stripped and a couple of hairline cracks re-welded.  This will call for a trip to my welder – cause I don’t do airplane structural welding.

After drilling off the belly, my first order of business was to build the new one.  That way, I could cleco it on to test fit and keep the project aligned.

It is 0.040 2024-T3, and I got a 4×6 sheet in person from Wick’s aircraft.  It was cheaper than shipping it in from anywhere else.  I was able to straighten up the old belly good enough to use it as a template, and the whole project thing came together in only a few hours and clecoed into place beautifully.  Any areas where it was too damaged to locate any parts were intentionally left large.  It’s easy to trim a piece shorter.


Any footballed holes on the old belly were ignored while drilling the new belly.  Once the new belly was clecoed in place, I was able to get those holes by drilling through the holes in the structure back outward through the belly.  I am very happy with how the belly came out.

Once the belly was re-built, it was time to take it off again for access to the work.  I swear I have had this thing off and on at least a half a dozen times already, and I have a LOT more times to go.

With the belly removed again, I was able to splice the crushed former under the pilot seat.  I used a new former from Vans, and it went together rather well.

Here is the new bulkhead portion with its fresh zinc chromate resting against the old one.  Note the overlap.

I used an L-shaped portion from the unused part of the new bulkhead to double up the back of the flange.  It had to be drilled to fit the new belly, of course.

AC 43-13-1B says that it takes 66 #3 rivets to make this splice.  You can count if you want!

This is why we disassemble after drilling.  Not only are their burs, but even when drilling and clecoing, a LOT of little chips get between the layers.  Not good in a permanently riveted structure.

All the rivets driven – except the ones that go through the bottom of the flange into the belly.  I am pretty happy about this repair – and if the rest of the project goes like this, I’ll be done in no time.  (Ha ha ha.)

After forming the belly, I decided to splice the F404 side pieces (F-404A-L x 2 and F-404A-R x 2).  I formed nice patch plates from annealed material and heat treated them to give me extra strength.

Damage reminder.  Other side similar in scope.

Splice plates being made of annealed aluminum.  You can see the blanks and my home-made flanging dies.

Bending the  lip.

Lip formed.

Four of the plates – one for each of the F-404 side formers.

Bake at 930 F for 30 minutes, then quench in cold water.  Metal goes from 2024-O to 2024-T42.

And the obligatory zinc chromate…

Fitting over the damaged formers.

Picking up existing holes.

Clecoed in place.

Riveted in.

I spent several days of work on this process, but was not happy with the result.  I didn’t feel that the covers could be fit in a structural manner, and I wasn’t happy with the alignment on the right side former.  So I decided to drill them out, and replace them.  Several more days of drilling ensued, than a lot of time waiting for new parts from Vans, which did not have them in stock.  In the meantime, I had also noticed some cracking on the lower left engine mount, so I decided that had to be replaced as well.

While waiting on parts, I decided it was time to go wild on the forward parts of the plane.  I removed everything but the structure I intended to keep.

Parts to be removed

While waiting for the new parts to come in, I built the right rear skin from another sheet of aluminum I purchased in person at Wicks.  It also clecoed into place nicely.

Then I started assembling the bulkheads that go in front of the spar together, carefully measuring each piece and only clecoing, so final assembly could be made into the aircraft and would guarantee fit.

Location of parts on forward bulkheads before removal and transfer.


I also used this time to begin assembling the firewall and bringing parts across from the old firewall.  I am really running out of things to do waiting for the bulkheads and weldament on back-order from Vans.


Good news – I have my parts.  Now it’s time to begin assembling the center of the airplane. Matching existing spacing and holes is critical.  Luckily, I have had several months to plan this stage.

Inserting the new former begins by locating the six spar web 3/16 holes that cross the former.  They are shown bolted into place with short bolts in this view.  This was done by aligning the locating holes in the new bulkheads with the locating holes in the old bulkheads, then pushing the the spar web holes through.  Now the piece can be bolted up as shown, and the rest of the rivet holes and spar holes can be match drilled into the former.

Match drilling as described above.  This technique allowed the rear formers to be done.  The forward formers were done in a similar manner, but since the forward spar carry-through bulkhead was drilled out of the plane, it was easier.

As the picture notes, this is the left front corner of former F404.  Everything has been match drilled and back-riveted in place.  You can see that the locating holes on the two parts don’t quite line up.  I’m not sure if the plans want this to be this way, but I am re-assembling an aircraft, and all my parts have to be how the original was – and this is how it was.  The holes in the lower left are for the trim cable and the rudder cable.  I’ll have to re-chromate the areas around the rivets on the floor support angles.  The only way to remove these rivets was to chew off the shop head with a micro-shave, and it has left some scarring.

While I wait for the Zinc Chromate to dry, I am going to jump across to installing the lower left weldament.

Luckily, I have enough drilled holes to perfectly align the new part.  I began by nestling the weldment into position against the special angle (bottom right of the photo, bottom left of the plane) and clamping it into place.  I was able to drill the existing bolt holes from the bottom of this angle into the weldment.  Then, I was able to push the side #4 rivet holes into the weldment – again from the same angle.  This allowed the end cleco to reach a hole in the semicircular brace, locating it precisely.  The rest of the holes in the semicircular brace could then be drilled into the weldament from the inside.  Now, the diagonal brace could be clecoed into place, and the remaining holes could be drilled into the weldment from the outside.  Everything precise and elegant.  I love this kind of puzzle.

As I go to cleco the frame together, I notice that the top weldament is not well aligned.  I can pull it in place with several clecos, but it appears to be sprung.  I start inspecting it closely, and find that it is, in fact, sprung.   Look closely at the photo above, and you can see how the two welded layers of 4130 steel are no longer lying next to each other – but have started to pull away.  That isn’t good.

Here is a view from inside on the same mount.  You can see the impression of the nut on the inside, and that indicates that there had to be some bending.  Looking much closer than you can see without blowing up the picture, I can see two areas of possible cracking.  And, as we all know, crack kills.  This is a $37 dollar part – so it’s going to be replaced.  That is a LOT of peace of mind for $37.

While I’m at it, I’m just going to replace both uppers.  That gets rid of a lot of potential problems, and it upgrades all the weldaments to the more modern and presumably stouter design.  Whats another eighty bucks compared to dying in a plane crash – or perhaps worse yet – (partially) surviving one?

Jason – helping me rivet in the new F404 side formers on the rear half of F-404.

Working the front half of F-404 into place over the control stick.  Note those beautiful new side formers…

After clecoing in the front half of F-404, it was on to fitting the other forward bulkheads.

Bulkheads setting in place.  They need lots of tiny adjustments to fit perfetly.

View looking forward from F-404.  You can see the missing skin panels and firewall – but all in good time.  First we fit the parts so they can be clecoed in place, then we disassemble, zinc chromate,


Keeping track of Budget on the RV4

Purchase RV4 – $5000

Haul RV4 – $500?

Run RV4 (oil filter and run stand) – $75

Printed Plans (Used) – $122 w/shipping

Wicks Aircraft RV4 new skin material (4×6 .032 and .040) $275

Vans Aircraft Bulkheads and Angles – $692 (Shipping killed on this one – Van’s shipped the firewall in a HUGE box that added a good $200 to the order total.)

Replacement Gear Legs and Engine Mount – $330

Less $500 for sale of smoke machine.

Purchase more bulkheads, weldament – $149

Purchase Zinc Chromate – $57

Purchase Fluting Pliers – $29

Purchase top two weldaments – $87? (estimated shipping)


Running Total – $6818



Beginning work on the RV4

Hello, and long time no post.

It’s sheet metal time of the year again, and I have decided to bite the bullet and put the RV4 into the air first.  Something about having an engine and a canopy convinces me this will go much quicker than finishing the 6.

The first task for the 4 was to take the engine off.  This was easier said then done, as the twisted metal impeded even seeing what needed done.  Thankfully, an energetic former student of mine stopped by and helped, and it went much better.  Thanks Trent.  Here is a picture of the engine and the landing gear standing on the engine stand.

Thanks to Keven for snapping the shot.  I will confess to slightly posing.  The next job was to get the twisted mount off of the back.  This was accomplished fairly easily, but  removing the landing gear legs (still unbent) was not so easy.  I finally had to cut one of the lower corners to release the leg.  Oh well.  That part was guaranteed to need re-building anyway.  Thanks to James for helping me whale on the legs with a hammer.

The tape shows areas that are definitely damaged.  I contacted McCutcheon (where the mount was built), and was told “sorry to say, but that’s a dead one.”  I had to concur.  I’ll try to find used replacement parts.  This is not just because of money – its also because I want to stick with the short legged RV-4 – and as far as I can tell, Van’s is selling only the long-legged parts now.  (I could be wrong, but that is all that is listed).

Speaking of parts, I wasn’t aware that I could get plans on a USB drive, and I advertised that I needed plans.  I was fortunate enough to find a set of used drawings, and I gave $118.80 with shipping for them.  This will have to go into my running total.

With the front exposed, it was time to start drilling.  I am hoping to replace only what needs replaced, so I have to drill each rivet out carefully without damage to the underlying structure.  This sounds a bit unfair, but I have to thank Seth for several hours of drilling on the firewall while I drilled off the sides.  Here is what I found underneath, after I removed all the obviously defective parts that came off easily.

And here is a pile of parts of varying degrees of reusability.

Landscape view.  You can see which corner has the most damage.  Unbelievably, three of the four weldaments came through unscathed, as did most of the structural angles.

Look at the ripped bulkhead/switch panel.  The other side is similarly ripped and shown below.


On to the bulkheads.  This is the pilot side, and you can see a compression failure/crack pretty definitely.  That’s gonna need replaced.  The Copilot side is even worse, and shown below.


These bulkheads and their angles are definitely going to need replaced, also.  There is a lot of buckling here – much more than you can see if the picture.

Other damage has already been photographed, so I’ll not include pictures.

Still not ready to tackle the engine, but now we can see the damage to the exhaust system.  This stuff is expensive, so we will get to try our hand at repairs.

My first order of business is to straighten the slight bends on the upper longerons.  These are not severe enough for me to worry about any damage.  It is far better to straighten than it would be to splice.  I’m sure not going to replace the entire longeron – it goes all the way back to the tail!

Note the very slight bend in the longeron just aft of the weldament.

Here is my straightening jig.  The angle has to be bent past straight, so it will spring back to straight.  Gentle and careful pressure with the C-clamp did a great job of straightening this little kink.  Still lots to go, but I am pretty happy about how that went.


Another RV Project!

So anyone who has been following this blog knows that I am into buying projects to get what I need.  While searching for my engine, I unexpectedly acquired another project – a beautiful and very repairable RV4 with an O-320.

Here is the pic of the plane before disassembly and transport.   The plane had a hard landing after a probable fuel starvation engine failure.  The prop stopped horizontally, so there was no prop strike.  As you can see, the main damage is the landing gear of the aircraft.  Interestingly enough, just like my RV6 project, this one is associated with the initials KW.

According to the person I got this from, the incident occurred 2 years ago.  He lost the engine on takeoff, and in order to miss the plowed fields, attempted the impossible turn.  He almost made it back.  Apparently he had fuel in one tank only.  I am guessing that some of the tank sealant came loose and blocked the fuel inlet – a hunch that was probably confirmed when I found a chunk of crud in the fuel line.

It took Jason and I nine hours to disassemble the airplane and load it for transport.  Luckily, the seller had a tractor and was able to lift it onto the trailer.

Here is the plane unloaded back and home – under the yellowish glow of the mercury vapor lights.  I bought Harbor Freight wheel dollys, and the plane is easy to move around.

Here is an up close of the primary damage on the left side.

Still the left side – this time showing the engine and the very damaged engine mount and firewall.  Of course, the real question is how much structural damage was done to  the inside.

And here is the inside.  Very little damage past the firewall.  Score on this side!

No question about it.  The right side is more heavily damaged than the left side.  Again the engine mount and firewall are certainly toast.

This time, the damage extends to the inside.  You can see the crumpled forward longeron angle that extends backwards towards the rear spar.  Luckily, this is only 24 inches long, so there is no damage or repairs needed to the corner of the aircraft aft of the spar.

For completeness sake, this is the bottom of the plane looking aft.  There is a lot of sheet metal issues in front of the spar, but nothing aft.

While looking at the underside, it is apparent that the exhaust is damaged.  Luckily, no damage is visible to the carb or the oil pan.

Another closeup of the problem corner.

Not sure how this happened, but there is a small dent on the spinner mount plate flange.  This can be easily removed.

No prop strike, but the prop could use refinishing.  The seller noted that he flew in some rain.

Turning my attention to the engine proper, I notice blue nitrided cylinders.

I don’t like this.  The plane supposedly has 787 hours on it, and the oil filter hasn’t been changed since ’08 and 713 hours.

Continuing to walk around the plane, I found a small tear in the trailing edge of the elevator – almost certainly unrelated to the crash.  No biggy, but there.

Look carefully in this picture, and you can see a crack on the edge of the canopy that has been stop drilled (right by the seat belt).  You can also see another smaller crack near the rear that has no been stop drilled yet.  The stop drilled crack was certainly not done in the hard landing.  The other one, who knows?

Here is the carry-through frame.  Look carefully, and you can see some tearing at the angle, right above the rear rudder pedal.  This one is on the right side.

The same spot in the left side is a little worse, with some crumpling of the side frames as well as buckling of the angle.

Where did the side impact come from?  Looks like an elbow of upper body got thrown against the upper ledge of the cockpit.  Note the small tear and bending forward of the roll bar mount.

Now lets talk seat damage.  Here is the floor under the pilot’s seat, and you can see that the right bulkhead is bent from downwards force.

Jumping out of photo order and into logical order, here is the seat that sat above that bulkhead.  He came down.  The recording G-meter reads 11.5 G’s.

The removable floorboard over the damaged bulkhead also shows some damage.

And here is the all-important registration and airworthiness certificate.  BTW, I have the builder’s photos, weight and balance, and the original airworthiness sign off and limitations from 1995.

No damages noted here, but you can see the paint is getting weak.

And here is the very repairable upper cowl.

The lower cowl is more heavily damaged.  It may of may not be repairable.

I had to remove the right flap and aileron to fit the wing in  my trailer.

Here is the fairly nice seat upholstery, along with the pilot’s seat belts.

The wing root fairings have a couple cracks, which probably should be addressed – even though I don’t think these were damaged in the crash.  It was a 23 year old airplane.

So this is an important picture.  Looking carefully, you can see a little crumpling on the fuel tank.  This is probably repairable – or even flyable as is.  What is more serious is the signs of fuel seepage.  Looks to me like someone was running mogas, and it managed to destroy the sealant in the tank.  Both tanks are this way, with multiple weeping rivets and seams.  I am guessing that this was the eventual cause of the fuel starvation incident, as part of the sealant presumable broke loose and blocked a fuel line.  In my opinion, these tanks need to be disassembled and re-sealed.  The good news is that you can see there is no farther damage on the left wing, save the pic below.

I probably put that dent in the wingtip lifting the wing.  I think it will pop right out.

Oh crap!  The right wing isn’t so lucky.  Here, the wheel got behind the spar and damaged 4 ribs.  No damage noted to the spar, though, so that is good.  Again, there are lots of signs of fuel seepage.

Here is an overall pic of the parts of the project not attached to the fuselage.  That is a Cessna 120 project  in the background.

We had a basic transponder.  this may or may not still be ago with the face plate reattached.

This shot is shown simply to show what instrumentation the plane has.

Here is the panel.  Note the radio (lower right) and the recording G-meter next to it.  The seller told me that one wing had inverted fuel pickup.  I have not verified it.  I have also not looked for or at the reported smoke system, but he said it was a blast to fly.

Here is the other side of the cockpit.  There is no throttle for the rear seat, but it would be pretty easy to add – just add a pushrod from this quadrant to the one you would need to mount in the rear.

Last pic, showing aileron spring trim.

So there you have it – an amazing find. I am torn between putting my RV6 project in the hangar and working on this one, parting this one out except the engine, which could go on my RV.

Update – the seller has located the log books (good), and I am waiting for them by mail.  In the meantime, I have struggled with what to do next.  I wanted to check out the engine, and debated removing it from the plane to do a trial run.  I finally hit on a scheme to run it on the fuselage as it was.

Here is the “napkin sketch” version of the plan.  We used an 8 foot board as a spar to hold the fuselage.  The tailwheel was secured to the trailer, and I used longer pieces of steel in place of the jackstands.  These stood on the ground, and ran through the trailer mounts.  They continued up and supported the weight of the aircraft on the new spar.

Here is the aircraft, along with some of my assistants.  We lifted the plane in place with the yellow A-frame, and decided to leave it there as an extra safety precaution.  After lifting the aircraft into position, we removed the drain plug from behind the carb, and spliced an external fuel line to the left  wing.  After replacing the battery, the fuel pump came on as it should, and in a few moments, we got fuel flow to the carb.  We let it run a bit to purge the lines.  Next, we removed the spark plugs, and sprayed penetrating oil into the cylinders.  We spun the prop by hand until the engine registered 25 psi oil pressure – pretty good for just spinning a prop by hand.  We replaced the plugs, and went to start the plane.

Here is an up close view of the false spar and the 2 inch square steel supports, as well as the gas line.

Here, one of my talented assistants is attempting to start the engine.  Unfortunately, there was no response to the key switch.  We determined that no power was reaching the solenoid activator (probably a signal wire tore loose in the hard landing), so we used a jumper wire to activate the start solenoid.

The first start attempt was a failure because the battery was too weak.  (I know – I just replaced it.  The replacement had sat in my garage for almost a year since charging).  The next attempt, my assistant forgot to turn on the mags.  We broke for lunch with the battery on the charger.

After charging the battery, we went back.  This time, the engine roared to straight to life.  You can see it in the video above, and you can tell I was a bit surprised.  I motioned to my assistant to cut the power and bring it back to an idle, but he was not able to slow the engine.  (Of course all you can see is a very unsteady video as I shoot with one hand and gesture with the other.)  I motioned him to shut off the engine, and he did.  The entire run lasted only a few seconds, but it verified the fuel starvation hypothesis as the cause of engine failure.  It also warmed the engine and circulated oil, so I could get a set of compression numbers on the engine.

So I got 77, 66, 75, and 70 out of 80.  These are pretty good numbers for an engine that has just sat 2 plus years.  Also, all of the leakage was identified as piston rings.  These will likely free up after just a bit of running, and bring the numbers back up to all in the 70’s.

After shutting the engine down, we also looked over the carb and the throttle linkage.  The reason the aircraft would not idle is that the bent firewall pushed the throttle cable forward far enough that the throttle could only adjust the carb from full throttle to half throttle.   I had only checked that the throttle on the carb moved when the throttle in the cabin was moved, and did not verify that it reached the idle stop.

This probably concludes my “investigation” until the logbooks arrive, and I can see if there is anything else to look into.  Still not sure whether to rebuild the airplane, keep the engine for my airplane and sell the airframe, or just sell the project.  If I was closer to needing the engine, I would definitely keep it.

I did talk to Vans about the airplane.  The engine mount with the landing gear is $1600.  I’m not sure I need the landing gear, but I’m not sure I don’t, either.  I’m not sure if they will sell a mount without the landing gear.  The firewall is 150 for both parts.  The plans are $225 without the license to build another aircraft.  This tells me that my $4000 estimate to rebuild the aircraft was a pretty good ballpark figure – BUT with an RV6 project rolling and a potential complete home renovation coming up (airplanes aren’t the only things I try to do on a tight budget), I’m just not sure I have time to work on this one.

Oh yeah – one more tight budget note.  I got the bolts to mount the airplane on the trailer for free.  This was because the credit card machine was acting up at Rural King, and the teller kept trying to make it work.  The guy behind me was in a hurry, and told the teller they would pay for the bolts in cash instead of waiting for repeated system reboots.  That was a 45 cent score!

And back again.  I finally got those log books in the mail.  They pretty much confirmed my suspicions that this aircraft didn’t fly a lot of hours after 2008.  They also show that the engine was rebuilt in 1990 before being put on this aircraft.  Also, I cut open the oil filter and found it to be good.

At this point, I have decided to try to sell the aircraft off.  I just can’t justify having two projects, and I really want the RV6 to be done.  The proceeds from this sale will fuel my future project.  I would keep the engine for the RV6, but I promised my wife I wouldn’t stockpile parts long before I need them.  So unless no buyers materialize, this project will be leaving my hangar and going somewhere else exciting.  You can really think of it as an ultimate quick build kit – the repairs will take a tiny fraction of the build time, and the cost will be far under half of what you would spend buying the kit and building, even after you buy all the needed parts.

If you are looking at this post from a for sale add, you can enlarge these pictures by right clicking on them, and selecting “open image in new tab” or similar.  Then, get rid of the “-300×225” at the end of the file name, and click enter.  It will then display in high resolution.

Framing the Fuselage

5-23-18, 1.5 hours Jay and Don.  5-24-18 2 hours Jay, 3.5 hours Don

So after the frames comes the framing.  We have already set out the fuselage jig, and laid out the frames in their rough locations.

Seems like you can never just go to town.  There are always so many more things to do.  Today (5/23), it was zinc chromate the seat ribs.

Not much to say about this.  The ribs are attached to frame 604 and 605 on either end, and form the floor of the seat area.  After transferring the measurements over, it was time to set them in position.

Here is the rearward end of a central rib jutting forward from 605.  It proved to be rather difficult to place them exactly in position vertically.

In the end, I clamped a sheet metal “ledge” to the upper edge of 605.  This allowed easy placement.

Here is the rib, set on the ledge and clamped in place.  One hole was already predrilled when building frame 605, so location of the first cleco was easy.

Moving outward from the center, clamping, drilling, and clecoing.

And here are all of our seat ribs in place on 605, and set against 604.

Clamping the ribs into position on 604.  Here, they fit into the lips on the rear of the bulkhead, so location is much simpler.

Drilling all the rivet holes in the bulkhead.  These will be riveted in place with AN426-3 rivets, so there are a lot of them.

Notice the two center ribs do not have the same drill pattern.  On of them (the left one) gets three screw instead of some 8 rivets.  This is so that the rib can be disassembled to allow the control yoke to be installed or removed later on.  More on this in a few pictures.

Jason drawing straight lines in to drill the remaining rivets on frame 605.

Drawing in.

And here are pilot holes all drilled.  We will enlarge the 3/32 inch holes as we rivet.  This side gets 470-4 rivets, and does not fit against anything flat.  This makes it easier.

Remember the disassembleable rib?  Here is the drawing showing where it is cut and bolted back together.  I have drawn in my line mostly as per plans.

The plans didn’t specify what to make the scarf piece with.  I went with .032 2024-t3 because I had a scrap the right size.  Here you see it being laid out.

Here the scarf is cut as per plans, drilled and clecoed for rivets, and drilled for the AN3 bolts on the other side.  The rib isn’t cut yet.

Drilling holes co form radiused corners

Cutting out the edges up front.  Here you can see the one change I made to this part – I left the tab on the bottom that will hold when the skin is riveted on later.  This will make this rib consistent with all the rest.  You can also see all the drilled holes.  Only now are we ready to cut.

And there is the cut.  Since we fit the rivets and bolt holes perfectly before the cut, it will still be the exact same shape when bolted back together.

While I was at it, I had to make a couple of small clearance notches in the next pair of ribs.  This is to allow the wing spar bolts to be installed without interference.

Once again, I start the cut by drilling hte corners.

Here you can see one of those ribs in place.  You should be able to see where the wing bolts will fit, and why the clearance was necessary here.

Here is the back side of the completed sectioned rib.

I set the section up on the fuselage jig.  It reminded me of a tugboat or an airtractor, so I decided to make airplane noises.

Actually, this was just an excuse to use the self timer and take my own picture!

I decided to set the firewall loosely into place on the wing jig.  Bad idea.  I slipped and drew my first significant blood on the project.  No stitches, but that end’s today’s (5-24) work.

One more view of the progress on the frame before calling it a day.


Fuselage Frame 605, 606

May 11th – 6 hours;  May 18 – 2 hours Don and Jay;  May 19th – 2 hours Don and Jay

It’s been some time since I last worked on the plane.  I blame work.  With the semester nearing an end, I needed to spend more time helping the students and less time being absorbed in my project.  But today was the last day of school, and I hope to kick butt over break.  The first step was to dig out the fuselage crate, and unpack those beautiful parts.

The firewall was factory drilled and partially assembled.  Frame 204 was factory jig drilled.  Frame 205 is the first part fuselage part that I get to do all by myself!  Frame 205 forms the back of the cockpit.  It consists of 6 large pieces and several smaller ones.  It also contains the aft “carry-through spar” (my term, not RV’s).

The first step to completing the frame is to join the two bottom bulkheads 605A R and L.  These are joined by a splice plate.  The rivet holes are spaced a bit weirdly, because there will be a hole in the center to allow the elevator controls to pass through.

Next order of business is to add 605B – the pre-curved 1/8 thick by 1.5 tall structural bar.  This sticks out on both sides of the frame, and will mount to the aft spar of the wings.  After this is measured and clecoed in place, the edge 605C bars are added.  These have a joggle and form a fork around the wing attach brackets.  They do have to be contoured pretty aggressively.  Thankfully, this can be done with a bandsaw and a power sander.  One per side, and we are ready to move on.  The edges of the spar forks that are formed should be 1/8 inch above the edges of the frame.

The 605D’s form the sides.  The 605A’s have to have part of the flange cut away to fit them.  Also, these have to have part of their flanges cut away in the top outside corners to clear the 3/4 by 3/4 stringer that will form the top of the fuselage boat.  No good picture of this.

I chose to go a bit out of order, and install 605F next.  This forms the seat rest along the top of the frame, and it is quite hefty.  At this point, a lot of very careful measurement had to be made to ensure the frame was true.  The top of the frame is 42.5 inches wide, and the bottom 42 inches wide.  Once I established all the proper dimensions for the four legs of the rectangle, I put a single rivet hole and cleco into each corner.  I then added C-clamps, and adjusted my diagonals until they were equal.  After that, I never released more than 1 corner at a time to maintain shape.

The plans note that the 605E’s and the spacer strips H and I are not needed if you are going to use a sliding canopy.  Since I don’t have a canopy yet, there is a chance that I will need them – so I am putting them in.  They are a little narrower than the 605D that they double up and reinforce, and the gap is to be filled with two strips (605H and 605I) that are made from .032 and .063 aluminum.  I just grabbed some scrap for spacing purposes.  Look carefully in the two photos, and you see one shot with the spacers in place, and the other after they have been removed post drilling.  I’ll add them back in when its time to drill and rivet the skin.

Also visible in the above photo, you can see the reinforcement extrusion 605G.  This is a 1.5 by 2.5 angle, 1/8 thick.  Any time you add a piece like this, tight fit is essential.  Both faces were clamped against their respective surfaces before drilling and clecoing.

At this point, the frame is assembled, and ready for zinc chromate and rivets.  I couldn’t help but lay out the frames in order, and photograph them.

That’s where I’ll be sitting – right in there!  Still not ready for any airplane noises.

Here are all the parts disassembled and zinc chromated.

Reassembly, with Jason as the master of the cleco pliers.

Riveting – a refreshing change to be installing universal head rivets.  Riveting went pretty smoothly with Jason placing the rivets, and me knocking them in.  I didn’t have to set down my tools between rivets, so things went pretty fast.

While Zinc Chromating frame 605, I went ahead and zinc chromated the next 3 frames.

These frames are much less work to assemble, as the tooling marks are also alignment marks.

Frame 606 is 3 pieces, and has to be measured diagonally to ensure proper shape.  Then the three parts are riveted together.  This frame is really, really thin.  There are 14 rivets to this frame, so it didn’t take long to finish this one out.

Frames 607 and 608 are two part, and are just temporarily set in place with two bolts each.  Here they are set on top of the fuselage jig, which I’ve just started setting up…




Frame 204 – Joining the Wings and the Fuselage

4-4-18 to 4-18-18 – 19 hours

So if you decide to buy a used kit, make sure you have the jig drilled parts where the spars and the fuselage join up.  This includes the steel splice plates!  Luckily, I have all of this in decent order.  Thanks for taking care of these, KW.  I don’t know if the plane would be buildable without these parts, which are to be assembled into frame 204.

I found all the jig drilled parts.  I didn’t find the side plates.  They are probably in the fuselage crate, but I figured it would take less time to fab them than find them.  Here they are – 2024-T3 and .063 thick.

Prepping the Jig Drilled parts.

First rivets in the fuselage.  KW had already drilled these parts.

KW had also drilled some of the side rivets, which had to be match drilled into my side frames I just made.  I love long bits for this task – they can be held in a bent position if needed while you drill.

Then the other side frame rivets had to be drilled in on 3 inch centers.  Later, when I skin the plan, many more rivets will go here on 1 inch centers.

Frame is looking good.

Now the other parts need drilled and clecoed to the side frames.  I had to temporarily bolt these to the spars to get the spacing right.  I also oopsied here, and made the first side backwards.  Luckily, the jig drilling was accurate enough that it did not matter.

Bolted in place.

Little nibbles to clear the rivets in the spar.  This needs to slide smoothly into the socket when its done.  A few minutes now will save hours later.

One side done.  This was when I figured out it was backwards.  I just pulled it off and flipped it over to do the other side.  Now all I need is a little nibbling and fitting, and the frame is ready to rivet and finish.

Here is a pic taken at a later date.  I still need to add the side caps at this point.

A Parts Airplane – Free Wheels?

If you have been following my adventure, you know that I am trying to make an RV6 on a budget.  This means I need to spend the least amount possible on my plane, and I learned a long time ago that buying salvage aircraft is the best way to stay on a budget.

I bought a salvage RV7A.  I won’t give the N-number, but I will say that this was a badly crashed example with two fatalities.  I paid $500.

Here is the plane on my trailer.  The wheels were the main part that caught my eye.  It appears that this airplane crashed upside down, because the wheels are just about the only thing salvageable.  It has Cleveland mains, and they are in good shape.

Here you see the crash spread out on the ground.  I invited the Flight Safety class over, and they took a good look at the crash.  It is a very sobering thing to know that people died in this machine.  This was a four year old crash., and the coroner and the NTSB have already looked it over.  Luckily, I found no signs of human remains – but plenty of signs of the former occupants.  I recognize so many of the parts that I have been working on.  Still, you can’t blame an aircraft for its pilot flying into IMC without and instrument rating, and life goes on.

This crash was horrific.  There was so little salvageable on the plane it was astounding.  I had hoped to get fuel senders, tank flanges, brake cylinders, and various small parts.  Almost none of these were ok.

I had hoped to pull a lot off the wreck, but beyond the wheels, I got very little.  The above and below picture show almost everything I kept, and much of what I kept is unusable.  The broken prop is going to my colleague to show in his props class.  The broken prop flange is going to engines class.

Now, its time to do a financial accounting.  I will close this page out when I find out what I ultimately paid, minus what I can sell.

  • Expenses…
  • Airplane – $500.
  • Travel – $51.07
  • Total – $551.07


  • Payout
  • Sold guaranteed broken transponder – $30 net
  • Sold Guaranteed broken Strobe Power Supply – $40 net
  • Sold Dynon Remote Compass Unit – might work – $30 net
  • Recycled aluminum (got a bad deal) – $59.70
  • Saber Prop Hub w/crush plate and F911 bolts – $225
  • 406 PLB – $26
  • Front Landing Gear Anti-Splat kit (bent) $45

Total to date = $95.37.  Trying to get to free!

  • Looking to Sell
  • Gear Legs (100 for set?)
  • Starter Bendix (30?)
  • Misc Hardware –  AN bearing ends for pushrods (65?)


  • Keeping
  • Cleveland Main Wheels, Brakes, and Tires ($2500 from Aircraft Spruce)
  • Fuel Tank Quick Drains and One Flange ($42 from Vans)
  • Fuel Cap (maybe) $28 from Vans
  • Oxygen system (still has O2 in tank.  Tank will need inspected.)


  • Perhaps Rebuildable
  • Matco Brake Cylinders
  • Matco Nose Wheel
  • ELT
  • VOR Antenna