Disclaimer

This blog is for entertainment purposes only, and is not meant to teach you how to build anything. The author is not responsible for any accident, injury, or loss that occurs as a result of reading this blog. Read this blog at your own risk.

Tuesday, May 26, 2015

Nose and nose gear - part 23

Nose cone shaping (12.4 hrs)

The day started out with mostly typical stuff, a little glass cutting, some slurrying, then fiberglassing the inside of the forward nose compartment.


Trying the fit

Glassed and slurried


Finished and cured


With the overnight curing process completed, I flipped the fuselage over and started the much dreaded contouring of the nose bottom. This isn’t a very difficult task at all, but like the nose gracing someone’s face, it will become the only feature people see if it turns out ugly. 

Having Italian sculptors, painters, and architects on both sides of my family, I was hoping to put some of my better genes to good work for once in my life, and pull out anything but an “Italian nose”.


Fast foam removal tool
Sanding the newest foam blocks


Time will tell, meanwhile there were a few things that needed to be fixed. 

Since I had prematurely sanded the bottom foam flush before adding the strut cover, I now had an eighth of an inch step between foam and fiberglass that would not be conducive to smooth lines. So, I cut two small slices of foam and glued them at their intersection, then smoothed the transition with careful sanding.


Outlining the new transition area

Cutting up some thin foam shims

Left foam shim in place

Both shims glued and curing


As you might imagine, very little of the foam slivers remained, just enough to smooth things over. 


Shims mostly sanded down to create a smooth transition


Sanding the nose looked like what you might imagine, proceeding in small increments, then stepping back to take it all in, and judging where to sand next. However, once the rough shape was attained, I employed a technique I made up on the spot, but which proved very effective at achieving round contours that blended across multiple bulkheads.

Using a 36 grit ceramic sandpaper strip that I cut off a belt too wide to fit in the belt sander, I ran it diagonally across the bulkheads to tie the surfaces together…


Working on the cone

Tying the 3 foam zones together


… and perpendicularly to the fuselage centerline to make sure the different stations were round.


Rounding the second zone


Every few strokes of the sandpaper, I would run my bare hands down both sides of the nose feeling for symmetry. It’s amazing how sensitive fingertips are at detecting unwanted sudden curvature changes, and differences left to right. After a while, a decent nose started to emerge from the foam blocks.


General shape sculpted


Even so, a few low spots remained that got filled in with micro then sanded.


Filling all the obvious low spots

Profile view of the fuselage bottom



Though the nose started to look pretty nice, a more careful inspection revealed the low spots to be wider than I had originally assumed.


I'll mix up some micro later and fill these slightly depressed areas

I put the epoxy work off for the day, and pulled out the Dremel tool. I wanted to start prepping a few flox corners for when the nose will get its glass.


Removing foam and dried up micro from the site of the new flox corner

I could have skipped the lower flox corner, but I wanted more adhesion where the bumper will go.



Thursday, May 21, 2015

Nose and nose gear - part 22

Strut cover and bottom nose foam installation (9.4 hrs)

One item that I had left unfinished was the foam piece directly in front of the nose gear hinge. In order to have easier access, I should have installed/glassed it before I closed up NG30 with the F6 bulkhead, but it worked out anyway.


Scuffing up fiberglass and dried up micro

Preventing a mess from happening beats having to clean it up anyday

Glassing action

Trimmed a bit long (for now) after cure
At full extension

Because I had split the strut cover (SC) into three pieces, then put it back together with a splice, I was left with a slight depression where the gap used to be, so I filled it out with flox, peel-plied it, cured it and sanded it.


Joint between old and new glass

The depressions were filled with flox and peel plied over


With SC ready for testing, I reinstalled the electric actuator in the nose compartment, and looked for interferences. I found them two. 


Actuator colliding with strut cover


The process for removing them is very straight forward, just sand them until they disappear, but it is very tedious because it involves going back and forth between sanding and fitting many times. That’s what I get for building a plane from plans, instead of buying a perfectly machined airplane kit.

So, I thought I would film the process to give you an idea of what it’s like.





A day in the life




After going back and forth a bunch of times, I was able to achieve a satisfactorily fit, that still minimized air infiltrations.


Interferences removed

The actuator travels unimpeded now


Then I floxed SC in position.


Usual stuff here, a bit of epoxy...

... on all mating surfaces...

... then mix some flox...

... until it's like soft butter...

... then apply it to the joint...

... mate the two parts...

... add some gravity...

... and fast forward 24 hours.


The next day I worked on closing up the last three remaining holes in the bottom of the nose. I cut three foam plugs, microed them them in place, and weighted them down overnight.


Not a perfect fit, but still acceptable.

Another look at the plugs

This level of protection turned out to be an overkill, since there was no sagging of the micro.

Micro applied to foam after slurrying it, and wetting the glassed surfaces with pure epoxy.

Gravity to the rescue once again

Next day




Tuesday, May 19, 2015

Nose and nose gear - part 21

Fwd nose compartment - inner sidewalls (5.0 hrs)

While the nose appears to be such a small part of the plane, it seems to be taking quite some time to complete, no doubt due to my other interests loosely related to this project.

This time around I worked on the inside surfaces of the forward nose compartment. I decided it would be easier for me to follow the same path as with the main part of the nose, glassing the sidewalls and the floor separately.

This straight forward task was somewhat complicated by my long period of fiberglassing inactivity. Because of this, the pump ended up needing to be thoroughly cleaned, since the hardener had gelled up a bit, the resin had crystallized, and the pumped ratio was all out of whack.


This is about as much fun as scrubbing public toilets!

Resin crystallized

This crystallized resin was later melted back


After consultation with Aircraft Spruce, I ended up heating the chemicals to 160℉ for half an hour as I have done in the past, and pressed on.

Before finalizing the inner nose structure, I wanted to make sure that the battery I have selected (Odyssey dry cell PC680) would fit, so I built a fake one out of cardboard to the proper dimensions (7.15" x 3" x 6.65" or 18.2 x 7.6 x 16.8 cm), and placed it in the nose. 


Cardboard getting glued together...

... and taped.

Here's an exact representation of the battery size

Plenty of room to spare


Since, that turned out not to be an issue at all, I moved on to glassing. First, I worked on the right side with the fuselage laying on its side.


2 BID sheets cut to size

Masking magic

Curing overnight


Then, I rolled the fuselage over to the other side, and glassed the left sidewall.


Left  side ready for glassing

Left sidewall finished

Both sidewalls fiberglassed

Next time I'll be doing some finishing work on the strut cover, then mount it.