June 4 - Wing tips and empennage tip fairings (work done in Jan 2017)

I made a couple of mistakes on the wing tips that would be good to avoid.

So, if any of you haven't done this yet - two pieces of advice:

Tip 1 - Don't assume if you get a great fit on the forward part of the wing tip (i.e. it fits super tightly on the forward curve of the wing) that it will fit or be a peachy fit once it is tight with either rivets or nut plates/screws.

 Make sure above all else that the tail edge aligns with the aileron when it is set to it's "in trail" position with the stick you made to align the ailerons properly.

 If you didn't do that (my original one was wood) I'd go to the hardware store, get some cheap straight aluminum yard sticks, and match drill those to the specified tooling holes in the tip wing rib.

 There is a *lot* of wiggle room with the tip trailing edge if it isn't nailed down. Use that flexibility to get a great alignment with the aileron, then working forward alternating top and bottom match drill to the skins and cleco it down.

 You'll probably have a fairly close fit to the forward skin, but the aft part is by far the harder to move after the fact, especially after you've installed the ribs.  The imperfect fit forward is easy to fix with micro or Superfil.

Once the ribs are in the trailing edge is nearly immobile.

 Tip 2 - go lightly with the trimming around the aft edge where the aileron hinge brackets are - it's very easy (I did it) to over trim then have to rebuild the skin to get a good fit.

 If you do foul either thing up like I did (I went for the tight fit forward idea) flox is your friend. I'm using nut plates and had to drill them all out and fill the holes with flox. Worked great. Actually seemed to be as strong as the tip glass.

Some pics

Getting ready to do one of the elevator tips.



Didn't have to trim it much - I just hit it with my hand held belt sander to get it straight and to clear some of the rivets.



Had to trim it just a bit at the back because it tapers to a point.



This is when I was first putting in the nut plates thinking that a great fit at the front would guarantee a great fit at the back.  Here's hoping you get both - surely someone must get  lucky every once in a while.



And this is after realizing that I couldn't get both, so I'd drilled them all out and was getting ready to flox them.  Epoxy sets up great on a warm day. :)



Holding the elevator tip tightly to the tip for match drilling.



Match drilled and dimpled and checking the fit.  I just did the dimples with my hand deburring tool.



Nearly done riveting it to the elevator.



Flox after curing and a boatload of sanding.  This is some seriously tough stuff.



Close up of the sanded flox.  It's transparent, but hard as nails.



Back side of the floxed holes.



Match drilling the wing tip rib to the tip.  I put mine in a bit further than the plans called for (maybe 1/8" or so).  It fit better that way.




Making sure everything lines up and the trim lines are all correct.  A lot of putting on and taking off of the rib, the tip, and the aileron to get it all right.



Working on the horizontal stab tips.  For mine, I found a curve gave a much better fit.  I was actually able to put the elevators on then trim the tips close to where they needed to be and put them on over the whole thing.  Made finding the final trim lines easy.  I'll spot clue some pink builder's foam in the hole, then glass over the top of it, and melt the foam out with acetone (got that tip from a Velocity builder friend).



It's funny - nearly done with the project and finally got a rivet fan.  Needed some bits from the Yard Store and decided to get one.  Would have saved a lot of time.  Using it to lay out the holes for the tip rib made it extremely easy to get good spacing.




Making a mess working on various things at the same time.



Contrary to the plans, I drilled my interior rib to the skin before I epoxied it in there.  I couldn't find a good way to hit it drilling blindly.  What I did was use the fan to lay it out, drilled it on the table, then put it in place and used my right angle "tight fit" drill kit to back drill to the wing tip.  Then I scuffed everything, floxed it up and used a couple of clecos to keep it in place while it all cured.  Easy to drill through the holes after it's cured, countersink and rivet.  I was pretty happy with how it came out.

Tues Jan 24th, 2017 - wheel fairings catchup

Sorry about the lack of updates. I've been working on the project, but finish late enough in the evening that I don't want to do an update so I let it go.

The last update was on the nose wheel fairings.  After I was done with that I started on the mains.  Basically the process is similar, but because of the angle of the mains when unloaded it's pretty important to install the wheel fairing and particularly the leg fairing with the gear unweighted so that it's aligned with the line of flight when airborne.

This first shot is how I did that.  I have a couple of boxes that I use to stand on and a long piece of dead straight aluminum angle (from riveting the rudder trailing edge way back when).  I dropped plumb lines from the fuse centerline down to the angle, which I leveled and weighted so it would be dead straight fore and aft and I could use it to align the longitudinal axis of the wheel fairing to.  It's easier than it sounds.

The stand with the jack on it is how I got the wheel off the ground. I put a long 2x6 under the main spar and jacked against that.  Worked great.




Just starting to get the fairing trimmed to get it over the wheel and around the gear leg.  The 2x4 block at the back is to hold the aft fairing level.  I also taped a wood block 7/8" (IIRC) to the top of the wheel to give correct internal tire clearance per the plans.




This shot gives an idea of what the gear looks like unweighted.  It definitely is canted from the vertical.




I clecoed the two halves together when trimming the cutout for the wheel to keep it symmetrical and so the lines would line up.  Used my Bosch jig saw with a metal blade for cutting, which worked very well and left a pretty clean edge.  Just needed a quick hit with sandpaper to take the sharp edges off.




Starting to get close to a decent fit at this point.




Inner view of the same setup.





It was pretty easy to drill the holes for the mounts to the tabs.  Just marked them with a sharpie and they were easy to see through the glass.  They only needed to be bent slightly to sit true to the glass surface.  Nut plates were installed later.




I finally hit on the best trimming method when I was on the last (right side in my case) fairing.  I just screwed two 2 foot 2x4's to my bench at the right distance apart, then clamped directly to them.  Worked really really well.




Fitting the right aft side.





Better shot of how I did the plumb bobs and the angle I used to make sure everything was straight fore and aft.



Rather than make my own intersection fairings, I found some on the net.  There is a guy in South Africa (http://rvbits.mybigcommerce.com/) that makes fairings and everyone spoke pretty highly of them.  I was going to order from him when I found that Cleaveland had them.  Cost nearly the same and I got them in 2 or 3 days.  I'm not an expert, but I don't think I could have made fairings as good as these even in two or three tries.  They look and fit great and are very well made.  Really happy with them.




Starting on the leg fairings.




Notches at the top for the hose clamp that will secure them to the gear leg.




Quick mockup to make sure they are the correct length.  I hadn't installed the hinges yet.




Here's the right side after it's finished.  Came out pretty well.  Hopefully I got it aligned correctly, but I won't really know that until first flight.





Here's another shot of the whole thing set up.  I'll secure the intersection fairings either with screws, hinges or perhaps a combination.




Time to move on to the bottom wing skins.

Wed Dec 28th - nose fairings

Time to catch up on what's been happening.

I've been doing a lot of work on the project, but haven't had time to post anything.

 I'm going to break the wheel pants and fairings into a couple of posts.

Once I had the gear and wheels installed, I decided to go ahead and do the wheel pants and fairings.

I started with the nose wheel. I don't know if there is a really great (or better) way to approach this, but this is what I did.

After doing a couple of pants I got better at it, but for the first one (the nose wheel pant in my case) I really snuck up on the fit which means it took a lot of trial and error, just making very minor trim adjustments as I went.

I started by opening up the large wheel opening first.  This was my first cut at trying to find a way to securely hold the wheel pant while I trimmed it.  In my case most of the time I used my jig saw with a fine tooth blade.  It makes a nice clean cut and is pretty easy to control.

Later on I came up with a more secure system using  a couple of 2x4's screwed to the bench that were a tight fit inside the pant.  By clamping to those I was able to get at the fairing very easily and it was held very securely.

I didn't realize at first how much I was going to have to enlarge the hole.  It ends up needing quite a lot of clearance to give adequate (I'm using a finger width) gap between the wheel and the pant.



Here's the first time I could actually get the pant onto the wheel enough that it sort of fit.  At this point the forward piece has not been trimmed.  It need to be relieved around the gear leg before it will mate up with the aft part.



Starting to trim the forward part just to get a sense of fit and so I could drill it to the aft fairing.



Forward has been trimmed enough that I can fit the leg fairing.  That's important so I can get the length down and also so the closure for the cowling can be fabricated.

Notice you can see my car jack under the nose.  I used my old stands with my floor jack and a large 2x6 to jack the wheel up until there was no weight on it.  That's how the plans specify to fit it.  Obviously it also needs to be large enough to handle any wheel expansion from landing forces or a/c weight, but it does make it easier to work on.



Much better fit at this point.



Starting to lay out the holes for the nut plates that will attach the fairing to the wheel.



Getting ready to drill the cowl support to the engine mount.  Very tight fit.  I used cleo clamps to hold it in position so I could get it where I wanted it before I drilled it.



Another shot of it clamped before drilling.



The more or less completed lower cowl bracket.



Checking the leg fairing fit to the lower cowl bracket.



Lower cowl bracket in place with pins.




Trimming the gear leg fairing to fit the lower cowl bracket.



Installing the nut plates.

Sunday, November 6th main and nose gear, wheels, brakes, etc

I got tired of working on the windshield and cowling, so I decided it was finally time to the gear installed.  I've had the fuse sitting on a fairly large frame was basically some short homemade sawhorses with moving dollies underneath.  One frame was forward under the firewall, and the other was under the main spar.

The working height was set to make it easy for me to stand outside and reach in, but that wasn't high enough to allow inserting either the mains or the nose gear.

My plan was to raise the fuse by alternately lifting the fuse so I could shim the aft support, then using that as a lever to raise the forward fuse so I could shim the forward support. By alternately working forward and aft and using some 2 x 6's I had, I was able to raise the whole fuse about 4", which gave enough clearance to install the main gear legs.

The thin stuff on top is some 1" pink foam insulation from the hardware store.  I was also using that as a support when I pushed on the aft fuselage from below to lift it high enough to slide in the shims.



Forward shims.  At this point I was high enough to get the gear leg in, as you can just see in the upper right corner of the picture.



Gear legs being installed.  I did have to shim it a bit higher after this to give me space to put the wheels on.



The axle had to be polished a bit. No corrosion since I've had it stored in my shop which is dry and clean, but there was something on the surface (protectant) that I needed to polish off so the inner mount and bearings would slide on.



Parts out and ready to start assembly.  The wheels and brakes that came with the kit are Matco single piston units.  Ken Stitt told me he was very disappointed with the braking performance on his RV-7 and switched to Grove dual piston units.  My A/C is a bit lighter and a bit slower, so I'll give these a try.  The Groves are a simple upgrade if these don't work like I want.




Starting to assemble the wheel.



Brake caliper.  Took me a while to figure out how all the bits went together.



The inboard support bracket needed to be reamed - there was powder coating in the hole and it was a tiny bit undersize.  I also had to run crocus cloth through the through hole in the axle to get the bolt to slide into place.



Everything assembled.  I don't know if these brakes are different than the originals specified on the plans, but I had to remove some material from the wheel pant bracket to allow clearance for the upper arm of the brake caliper unit.



Axle bolts.  The come pre drilled for cotter pins and also have the nutplate already installed to provide a place to mount the outboard wheel pant support bracket.



Installed and ready to go.  Once it's torqued, you need to drill the axle for the cotter pin.




Starting on the nose gear mount.  I didn't think to ream this hole out when I installed the motor mount, so I had to get creative trying to enlarge it enough to get the bolt in.  I couldn't get any sort of drill in there (even an angle drill), so I used my drill bit and a pair of vise grips to enlarge it by hand.  Worked surprisingly well.



Bearings for the nose wheel prior to packing.  I just pack them by hand.

I asked Nick what kind of grease to use and he told me he uses high quality marine grease to resist corrosion, so I followed his lead.  We'll see how well that works.



Nose wheel before installing the tire.




And here is a shot of how everything goes together.




Nose gear fork installed below the upper limit stop.  There are two holes on the upper side of the yoke that will receive a pair of allen screws that provide the limit stop action.  They allow the gear to rotate to about a 90 degree angle, but no further.





Everything more or less assembled.  I still hadn't set the breakout force on the yoke yet because I didn't have a spring scale at the time.  I did that yesterday afternoon after picking up a scale.



Starting to look like an actual airplane.