The Volutera Cozy Mark IV Project #1504 by Alexandre Souto

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Ch04 - Fuselage Bulkheads

I initiated for the 25 BID reinforcements of the main landing gear. I confectioned all parts, but it left with many bubbles. As I mess in the setting of the reinforcements, I destroyed them and confectioned others.

The second time I used vacuum and the parts was perfects.

The four parts weight had reached in the first case 602 grams, while in the second was 548 grams, 8,97% of difference.

07/12/2007

Step 1 - Front Seat Back.

In the tips of security of Eduardo Hilton, I lean that the more inclined the seat, minor is the load of G jamming the vertebral column in case of a crash. My seat will have inclination of 42°, against 45° of the plans. Initially cut the foam aprox. 1.5" big in height than the specified size. It is sandpapered with 120 to form a smooth surface. After it is applied Micron and Epoxy, already with the hardener. It leaves to reach almost the gel time so that not pass for the cloth.

 

After the lamination comes peel ply, the perforated film, the absorb film and the film for vacuum.

Applied 12 " Hg of vacuum. The upper main landing gear bulk is being finished in this bag too.

Tip: to keep the film for strained vacuum is easier to stamp with the mail tape.

Everything functioning perfectly inside of the heat tent.

Gradually (~2°C/min) temperature is raised until 60°C, keeping it during the cure time (6h).

After 24h of complete cure, they are exposed to the sun, covered with black constructionplastic until reaching 80°C, for after cure, during 5h.

All this process it`s called German method of vacuum in composites.

Two thermometers in the heat tent to calibrate the temperature, the central have the connecting rod of 30cm, so is more accurate.

While the vacuum-gauge of the pipe chamber mark`s 20 " Hg, the vacuum-gauge of the bag show`s 12 " Hg.

The vacuum pipe chamber has 1m x 0,10m Ø.

12/12/2007

Back of it I lean in aramide Twaron 2200 HM dtex 1610, this wire is not ballistic as the Kevlar29 and Twaron 1000, it is for plastic reinforcement, equaling to Kevlar 49. Fabric kk205 of TEXIGLASS. The substitutions for aramide will be made where the tension predominate, and in not structural parts.

As the part is big, and the aramide one is more difficult to impregnate than the glass, I used the wet out technique.

Perforated film, allows the exceeded resin to pass.

All stamped on bag. The foam that I use is the H80, the plans indicate H45, however, as the inclination will be bigger, and the foam is the responsible for the distribution of loads between fibers, the use of one foam with properties 55% superiors will effectiveness distribute the loads.

13/12/2007

The additional aramide strip, not contemplated in the plans, however the same one will serve to hold the pressure of leans it of head, in case of an accident or incident, and that I never wait to need.

It is not possible to sandpaper the aramide, untied it amount of fuzzy hairs. To trim with sandpaper also is impossible.

The solution is to plate one superficially glass fabric for finishing, and to trim use only one stiletto, up to 3 layers. In this part it will not have painting finishing, only the leather.

The part, but still for trimming the corners and bevel the center console, what I will make only in chapter 6 for a perfect adjustment, weighed 2412g, against already beveled of:

Wayne Hicks -2204g

Bernard Siu - 2341g

Kevin Dove - 2500g

Douglas Walters - 2585g, without the center hole.

Chasing Mars - 2917g, with door and H80

That is, perceivable the use of the professional vacuum, and also the use of kk205 that is 150% superior to the glass in tension; inferior to RA7725 in compression only 9%; it weights 32% less than the glass: 200g/m ² against 298g/m ².

Already practically in flight. Only that the seat will not be rose.

31/12/2007

Step 2 - F22

Situated at 22" of the nose, this bulkhead receives a strap foam addition on the opening of the legs.

It shields it already is ready to trim. I will use the method of Drew Chaplin to contour it. I will not remove the peel ply until the moment to join the fuselage in chapter 6.

07/01/2008

Opposing above detailed. I did not use the method of Chaplin, I just placed paper carbon on of peel ply, passed the drawing of the plans for the part and later trim with the saw and the sandpaper. Later I only removed peel ply. The temptation is great to see how the part was. But the part was very good. Without defect.

Make everything and later trim is much easy, little work and little time.

The verse of the F22 possesses reinforcements where the canard will be mounted and its setting.

13/01/2008

F28 - Ready to be installed. It was strengthened beyond what the plans indicate to contain the supports of the hinge of canopy, which will also be fixed in the longerons, as Ed Richards made it.

For the plans they are 2 BID @45 and 1 UND horizontal line.

Mine schedule was of 4 BID @45, 2 UND horizontal line, as hard points of 7 " had been: 1 covers BID @45 and 1 covers UND @90, of the two sides and in the two extremities.

The inferior part also was left wider, with 5 " for setting of the canopy hinge support.

02/01/2008

Step 3 - IP

Glue with 5min Epoxy, it is fixed with ribbon in the style of a hinge, transfers the Epoxy in the opening of the other side, closes the hinge.

 

I applied pieces of peel ply to absorb the Epoxy excess.

 

 

The easy way to trim is to pass the contours with pens marks compact disc over peel ply.

When the plans or the drawings give the dimensions use them, exist much distortion between the drawings and the quoted measures.

I go to trim the corners when ready to install it in the fuse. By this way, I don`t take the risk to have to fill gaps with resin and flox.

The inferior part in the drawings is 1/4" minor, many constructors has that to place foam for adjustment to the deep of the fuse. People make this bulkhead with 0.25 " bigger. It is much easier to take off.

11/01/2008

Dennis Passey leg cutouts, real cool. Reinforced below the leg cuts. After I will layup one overall carbon BID ply.

Almost done, just cosmetic repairs.

I removed the above part of the panel, will install the keys in other parts of the panel, also being able to be installed in the superior part of the canopy or in the interior of strakes.

Contours in all the reinforcements for comfort of the legs. Still it lacks to trim.

09/01/2008

Step 4 -

Manufactured with Divinycell HT110, against the H100 of the plans, superior to this and it is for aeronautical use.

However slightly more weighed, as it can be perceived in the comparison of FWD LG below (328g).

13/01/2008

Ready for installation. It can be perceived that it was in the weight average of the others, although the HT110.

16/01/2008

After cure I trim my pieces.

08/01/2008

Upper portion of the FWD LG

02/01/2008

Step 5 - Firewall

Manufactured with naval plywood of ferrule and Arana cedar from COMPEBRAS, superior than the indicated in the plans. It leads you incrust of aluminum in the same thickness of 1/4 ". The incrust have 2 " x2 ", against  1 " x1 " of the plans.

BID. @45.

After the laminate comes the peel ply.

I can use the perforated film 2 or 3 times.

Cloth to such the excess of resin.

All bag stamped.

The film for vacuum can be substituted by any plastic of construction or greenhouse, only that the professional material is perfect and can be reused 3 times.

07/01/2008

Here the welded screws with flox.

Done.

08/01/2008

Ready for the installation. I only go to trim the superior firewall when I decide if I increase the turtleback .

 

Peso das peças/parts weight (grams)

Ale Souto

Naca Scoop

Ale Souto

P-51

Wayne Hicks

Bernard Siu

Kevin Dove

Chasing Mars

Cozybuilders.org

Seatback

2412

2310

2204

2341

2500

2917

2358

F22

1037

1029

948

992

1000

N/A

952

F28

385

360

303

226

292

N/A

317

Instrument Panel

2090

2019

1700

1808

1900

1944

1950

Top Firewall

on hold

on hold

N/A

1513

1500

1510

1678

Center Left Firewall

116

116

N/A

141

145

279

204

Center Right Firewall

116

116

N/A

136

145

279

204

Bottom Firewall

1005

1179

N/A

1672

1250

1244

1451

FWD LG upper

328

328

317

368

500

315

408

FWD LG lower

618

698

598

714

700

628

771

AFT LG

1173

1323

1143

1326

1000

1125

1360

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