Tail Fairings

[kmbusse]

Completely new to fiberglass and not quite clear on closing the openings of the horizontal and vertical stabilizers. You attach the elevators and rudder, mount the fairings and trim to get an 1/8 in gap. I get that, I get laying up 2 pieces for the cover. Then it says to trace the fairing on the cover, trim, tape in place and then finish attaching it to the fairing with more fiberglass. Here's where I'm not clear. Does the cover go over the fairing opening and then mounted in with more fiberglass, or does it get sanded down to fit inside the fairing to sit flush with the edge of the fairing and then mounted in? Maybe I'm reading it wrong but it looks like it is taped over the fairing, but doesn't that then get rid of the gap and bind with the rudder or elevator?
Any advice for the fabrication and fiberglass of these parts are also welcome, as this is our first kick at the cat.

Thanks,

Kerry

[Aluminum]

Originally Posted by kmbusse

Does the cover go over the fairing opening and then mounted in with more fiberglass, or does it get sanded down to fit inside the fairing to sit flush with the edge of the fairing and then mounted in?

I suppose both will work, but the first way is much easier: spot-weld an oversized piece, fillet the inside with flox, cut/sand away excess. Exactly as described in the manual worked well for me.

2-ply glass is quite thin if you lay it up between two pieces of plastic sheeting and squeeze out excess resin. Let it cure between plastic sheets: it results in stronger epoxy and stinks less. Sheeting will come off with no effort once cured.

If you are new to fiberglass here are some tips I wish someone told me before my first attempts:
- it cuts with tin snips, gelcoat no problem;
- diamond dremel wheels shape it quickly and won't go dull;
- sand/grind wet to control dust (mister not bucket if electric tools!)

Finally, be prepared for the esthetics of the fairings to be inferior to the rest of the kit. It would take insane hours and lots of micro to make Van's fiberglass blend in nicely with metal--and each other for that matter, see Tom Martin's tip (sadly his photos seem to have disappeared).

[kmbusse]

Thanks. That’s how I was reading it but thought 1/8 in wouldn’t be enough gap once the piece was on top. I’ll go with how it shows. I really appreciate the tips.
Kerry

[didja]

I am just now getting to this step for the horizontal stab and vert stab. As the OP stated, I am also a newbie to fiberglass. When looking to purchase glass, what should I be looking for in type of fiberglass and what epoxy/resin/flox products are recommended?

My understanding of this step is to use a spare sheet of aluminum and cut it to the shape of the opening of the fairing, then use that as a template to cut the shape of the fiberglass mat to then put in place. Am I misunderstanding the step?

Is this something that you can simply apply resin to some mat fiberglass, put in place, fillet the inside corners with more glass and then once it all dries and cures, trim the excess off?

I might be overanalyzing this......

[kmbusse]

I decided I wanted to learn more about fibreglass before I try so I put them aside and started on the wings.

Kerry

[Bgill]

I'll chime in as to what works for me. Definitely other techniques to experiment with. "Aluminum" above has some excellent points on cutting and sanding. The materials and techniques are just some that are used. You will find that some work better for you and others not so much. Mix and combine for various applications. You will definitely need techniques refined when the windscreen comes into play. Nothing to be afraid of, just a new skillset with its own tools and materials. The nice thing about fiberglass - if/when you screw up, grind off and re-do.

For the VS closeouts I just allowed epoxy/glass to cure on flat table (between 2 pcs of plastic, then cut to desired shape. For HS close out, used aluminum sheets to form angled surface matching trimmed surface. Applied direct to blue plastic surface and add one layer of plastic sheeting on top. Both applied to outside of trimmed end caps (cleco’d in place) {If the 1/8" spacing is a concern, you can cut back a bit off the end caps to compensate} with glass/flox mixture. Next day, remove clecos and apply flox’d filler or small glass strips to inside to reinforce joint.
After final attachment, I use “thin” glass cloth (approx. 1” wide) over the alum to fairing joint as described below – with the peel ply on top. After cured remove peel ply, roughly sand smooth, then with squeegee apply thin layer of fiberglass with Microlite filler (soft peanut butter consistency). Allow to cure and sand smooth. The Microlite is very similar to auto body filler in texture and use..

Materials I use:
Glass cloth (woven not the cheaper mat)– various thicknesses. Unfortunately, I don’t recall the specific thicknesses. Left over from previous build..
Flox (flocked cotton fiber)
Peel ply – place over final coat to soak up excess liquid and leave smooth (relatively) finish.
West Microlite – very fine fiberglass filler/thickener
West Systems Fiberglass (1.2 gal kits – with 206 slow hardener)
West pumps for gal kit (measures correct glass/hardener ratio in quick pump)
Rotary cutter (OLFA is one from Aircraft Spruce)
Chip brush 1” wide (cheap disposable – home box store) trim bristles to approx. ¾” long
Acid brush (cheap disposable – Amazon/ harbor freight) trim bristles to approx. ½”
Plastic sheeting as required..

Technique I use:

Roughly cut cloth oversize & Place on plastic sheeting
Wet out with mixed epoxy
Place 2nd plastic sheet on top
Use squeegee, fingers, what ever to move liquid around to completely wet cloth)
Cut “wetted” cloth with rotary cutter to size required. Cut through sheeting both sides.
Peal off one layer of plastic, transfer to part surface and place on part with plastic up
Peal plastic off.

[kmbusse]

Thanks for that post. It definitely helps. I really appreciate you taking the time to explain it.

Kerry

[didja]

outstanding post. thank you for the guidance!

[rvbuilder2002]

Originally Posted by kmbusse

Completely new to fiberglass and not quite clear on closing the openings of the horizontal and vertical stabilizers. You attach the elevators and rudder, mount the fairings and trim to get an 1/8 in gap. I get that, I get laying up 2 pieces for the cover. Then it says to trace the fairing on the cover, trim, tape in place and then finish attaching it to the fairing with more fiberglass. Here's where I'm not clear. Does the cover go over the fairing opening and then mounted in with more fiberglass, or does it get sanded down to fit inside the fairing to sit flush with the edge of the fairing and then mounted in? Maybe I'm reading it wrong but it looks like it is taped over the fairing, but doesn't that then get rid of the gap and bind with the rudder or elevator?
Any advice for the fabrication and fiberglass of these parts are also welcome, as this is our first kick at the cat.

To answer your orig question.....
The two layers of glass that the instructions say to lay up will only be about .030" thick (that is less than 1/32"). Since the gap is a minimum of 1/8", it should not be anywhere close to rubbing.
That lay-up is done in advance and pre-cured on a scrap piece of aluminum.
Once that layup has been bonded to the tip fairing (held in place with tape until the resin cures), a couple more layers is added inside, bridging the interior corners to tie it to the original fairing. This will not add any thickness outside so it will not reduce the gap dimension.
Once this has cured, you are told to then sand off the excess that overhangs the edge of the fairing.

[kmbusse]

Yes that was my concern. Having never done it before I thought 2 layers of fibreglass would be more than an 1/8 of an inch thick. Was worried I was interpreting the instructions wrong but sounds like I’m on the right track. Thanks again for all the help guys.