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.