Lucy

Lucy
Vans RV-7a #73391, N511RV

Her name is Lucy and that's her serial number and "N" number.
Sweetie is so supportive. We are going to travel and see this wonderful country. For those who don't know about Vans Aircraft, check out the Vans Aircraft link. It will take you to the manufacturer's web page where you can read all about the airplane.
Let's get started. Feel free to browse around and return often to keep up with the progress. If you have a comment or question, please use the form at the bottom of the page.
On to the Blog. The cover page is just daily ramblings. If you want to read the assembly details, click on one of the page links. Enjoy.

Thursday, April 11, 2019

THE BIG CUT!!!

Yea! Thank God that is over. I made THE BIG CUT! Check out the Finishing page for details.

Thursday, March 28, 2019

Epoxy Formula

My mentor, Dave came up to help and gave me a class in fiberglass. His formulas are so useful, I wanted to preserve them. I made some minor edits to his original text for my benefit.

Figure the volume of the layup, add 10% to 20% for wastage and to have a little excess (better than being a bit short, us short guys know about that), and then figure the amount of each of the two parts. Factor 0.010" for the thickness of each ply of fabric. If yours differs significantly, use that instead.

The West system 105 epoxy and 206 hardener mix at a rate of 5 parts epoxy and 1 part hardener.

1:5 is 20%. So divide the total by 1.2 and that's how much epoxy to measure out. Take 20% times that and that's how much hardener to use. The equations use a few approximations for simplicity. The density of the epoxy and resin isn't 0.05 pounds per cubic inches, but lower. It's easier to remember 0.05, though, and since epoxies vary, I use 0.05 as a rule of thumb density estimate for all plastics. I also round off the grams per pound to 454. Larry showed me a neat trick, using two large syringes: Suck epoxy in one and hardener in the other. It's then quite easy to get a precise measure, using a gram scale.

L is length
W is width
t is thickness per ply
n is the number of plies
V is the total volume of the epoxy needed
W is the weight of the epoxy in pounds
Wg is the weight of the mixed epoxy in grams
WEg is the weight of the epoxy in grams
WHg is the weight of the hardener in grams

Then,
(L * W * t * n) * 1.2 = V  using 120% (the 1.2 at the end) as the allowance for miscellaneous excess.
V * 0.05 = W, in pounds.
W * 454 = Wg, for the weight of mixed epoxy required in grams. 

The 1.2 may be adjusted down to 1.1 if there is a consistent excess.
I like using grams because it's easier to be precise using them.

Wg / 1.2= WEg Weight of Epoxy in grams
WEg * 0.2= WHg Weight of Harderner required in grams

And there you go. Simple.

Here's an example for a 12"x12"x Three Ply layup
12 (L) * 12 (W) * .010 (t) * 3 (n)= 4.32 (V)
4.32 (V) * 0.05= 0.216 (W)
0.216 (W) * 454= 98.1 (Wg)
98.1 (Wg) / 1.2= 81.7 (WEg) weight in grams of Epoxy
81.7 (WEg) * 0.2 = 16.3 (WHg) weight in grams of Hardener

Thanks Dave.

Edit: Another member of our group, Colorado RVs, Ryan, suggested poring epoxy and hardener into those ketchup and mustard squeeze bottles. Measuring would be as simple as squeezing portions into the container. I'm still debating which should be yellow and which should be red!

Sunday, March 24, 2019

My Slider Canopy Method


This is probably not the right way, and certainly not the Vans way, but it's working so far. I ordered all my canopy weldment parts bare so I could have them powder coated to match and not add additional weight.

I'm doing Sikaflex as well, so I prepped all the canopy frame parts, adjusted them to fit as close as possible then had them powder coated. On to method.

The roll bar was a non event once I figured out how to squeeze it. DO NOT use a ratchet strap. There's no way to release them gently. When they snap loose, the pipe actually expands and the problem gets worse. Use a "Come Along". It can be released very gently by manipulating the safety catches. The Harbor Fright unit works just fine. I needed one for my 4x4 anyway so I bought the "Big Kahuna". Get some straps as well. Rig it so the tension is as far out to the base flange as possible. Measure the span and proceed in increments. Squeeze a little more each time till the relaxed dimension is correct. Don't sweat the Brace for now. Prep it with the forward holes and trim but leave it a little too long. You'll see why later. Bolt the roll bar in place but leave the bolts loose. You'll only use it as a reference for adjusting the canopy bow until the canopy is done. No need to fight all those shims, washers and nuts. Just put it on loose. Chances are you will need shims and likely pull the bolts out anyway.

Canopy bow is another story. Plain old body weight and a pair of sneakers on your feet work pretty good to bend the bow. Use a pad. Note, it flexes out really easy but resists bending inward so if you need it outboard, do it in tiny bits. Conduit bender works very well but make a shim from copper tube so it doesn't crease the bow. Get it close, but remember, it will be adjusted later once the canopy is cut. The canopy pulls the frame out at least 1/2", plus you need it to clear the top skin so there's lots of adjusting using measurements. The forward tubes are long on purpose to allow for adjustment. Don't cut the forward lower tubes to final dimension till the canopy is attached. Also don't drill the rollers to the tubes yet. That way you can fine tune the height in relation to the roll bar. The plans show the canopy bow 3/8" higher than the roll bar to start. Cut a little to get the top dimension close but don't go too far. Final cut can happen after or right before the canopy is glued. Then the rollers can be drilled and bolted in place.

While you're at it, buff the screw heads on the roller tracks so they don't protrude outside the roller. This will keep them from dragging on the sides of the slider tracks. If you're using Flyboy Supertracks, now is the time to unpack that box because the rollers get modified with new hardware.

The slider tracks determine the width of the canopy. Later you will adjust the bow so after the canopy is glued, the slider rollers perfectly ride in the center of the tracks. Position the tracks so the side of the frame bow is 1/16" inboard to the fuse side. You can do it by measuring pretty easy. Mine ended up 41-3/16" apart. Try to match the dimension on the aft end of the tracks. Closest I could get aft, was 41-1/16" so I have 1/16" each side narrower. The canopy should squeeze that much easy enough. Note the location of the last aft hole in the tracks. It is very close to hitting the longeron. Measure and drill carefully. Don't nick the longeron drilling the hole. I bolted my slider tracks in place after powder coating because the canopy has to be in that exact location.

The plastic blocks are fun. Drill the bottom holes in the brackets but not the side holes. Clamp them for now. If your bow is not powder coated, heat the pin and use the bow to make a starting point then just drill to match. Otherwise, do the math, draw the lines, hold your tongue just right and try and get the hole correct. Leave these off for now too. Once the canopy is in place, they can be final drilled.

I recommend the Supertracks mod. If you install them, fabricate an extra long top track from AB6-250X500X48 Aluminum Bar and AS3-063X1X48 Aluminum Sheet. Don't drill it for the mounting holes. The holes are best drilled after the canopy height is determined. The track is moved forward or aft to set height. If you predrill those holes they may not fall in between skin holes. Waiting allows you to target the best locations for the holes.

All the other parts can wait till the canopy is glued and fits. Then the blocks can be mounted so the canopy pins hit perfectly. Supertracks may also be mounted.

Finally, the Roll Bar can be adjusted to match the canopy forward bow by shimming and the Roll Bar Brace can be cut to the correct length and drilled.

This was long but Vans instructions are for a drilled canopy without Supertracks. After reading VAF threads till I was blue, it was clear no one had documented the process very well. I had to reinvent the wheel. There's tons more little details and I have yet to actually make the Big Cut and glue the canopy. I will edit this post if things change.

Refer to the Finishing Page for specific details on how each step was done.

Thursday, March 14, 2019

New page

The list of links was getting really long so I moved them all to one page. Miscellaneous Tips and Tricks. If you can't find the link you want, please let me know. This process was a intended to preserve useful information. Many VAF threads have lost valuable photos over time so I printed them to pdf files and save them for future use. The links and files will not live here forever. I plan to delete links as those steps are completed on my kit.

Build on

Monday, December 31, 2018

Canopy

I'm officially in canopy he11! Check out the progress on the Finishing page. Lot's of notes and edits. Hope it helps someone down the road. I'm not saying my way is the right way, but it seems logical. I still have to make the "Big Cut" so my method may yet prove to be a total disaster. At least it's another option and points out some potential "Gotchas".

Friday, February 9, 2018

Aft Top Skins

Yea. Things are really moving. We riveted the Aft Top Skins. Check out the Finishing Page.