How to cover a plane- Frank's Chica

[Frank v B]

Before Andy bothers me again....

Here's how to do a Solarfilm hinge on the stab/elevator.  A Solarfilm hinge is when no actual hinges are used (pin or CA).  The reason is the tail feathers are only 1/8" thick.  A hinge would create a bulge and could weaken the wood.  A Solarfilm hinge uses the covering material as a hinge.  To be successful, the glue side of the bottom film must meet the glue side of the upper film.  When they meet and they are heated they will not come apart.
This is the same method I used on my two Nooners and all small hand-launched bullets.  They do not come apart as long as you stay sub-sonic

In this case I noticed it too late so I had to modify it from the usual 2 pieces of covering to 4 pieces.

The principle is to cover the top of the stab first and shrink it.  Then hold the elevator against the stab covering and put it in "full down" mode, then apply the heat and attach the elevator.  This way when it shrinks it will stay with enough "down" elevator so the hinge is not stressed.

Then the elevator is folded back completely flat against the upper surface of the stab (180 degrees up elevator) and the bottom of the stab and elevator are covered.

Problem: the left over covering was not wide enough to cover everything fully. 

The revised approach was to cover the bottom of the stab first, then the bottom of the elevator (photo 1397) and leave about 1" extra forward of the leading edge.  Then gave full down elevator (photo 1398) and sealed the 1" excess at the leading edge of the elevator to the top of the stab.  A photo of the elevator is in photo 1399.

Then folded the elevator onto the top of the stab (180 degrees "up" elevator, photo 1400) and did the same to the bottom.  The result was surprisingly good.  See photo 1401.

Try to follow along with the photos.


Frank

[Frank v B]

Finishing covering the fuse,

Covered the hatches.  Because of the curvature the folded edges required many slits. See photo 1402.  With all the folded edges trimmed, the underside of the hatch looked a lot cleaner.  See photo 1404.

covered the top of the fuselage with a triangular piece behind the wing's trailing edge and a piece of the nose. See photo 1403. These pieces made the top covering look symmetrical ("cosmetic", Andy).

Frank

[Andy Hoffer]

This is such a pretty build.  I hope you are going to wrap it in foam or bubble pack before you fly it! The corn will jump out of the field to grab such an offering!!

Andy

[Michael]

Great thread, Frank! 

[Frank v B]

Did Andy say something?  Dunno

Trying to explain how to do a hinge with covering is like trying to teach a person to tie a shoe in writing.

Here is a photograph of the 3 steps.

In the past, I have taped the elevator in 3 places to the stab with clear Scotch tape so you don't need a 3rd hand.

Will post the method I ended up using this afternoon after some family stuff.  The new method is easier for people with limited covering experience*.

Frank

* limited like mine!

[Frank v B]

Hinging an elevator with covering.  Alternative approach:

This method is actually easier if you have never done this before.  The reason is you do not have to mess with the extra covering for the entire stab.  You are only dealing with a small piece.

Once the elevator is ready, cut a piece for covering for the top that overlaps the leading edge by about an inch.  Attach this piece to the top of the elevator and secure the covering everywhere.  The hold the elevator to the top of the stab and let it droop down about 45 degrees.  Attach the one inch piece to the top of the entire width of the stabilizer.

Fold the elevator up and lay it flat on the stab (180 degree "up" elevator).  Take the piece of covering for the bottom, again, 1" overlap onto the stab and attach it to the bottom of the stab, fold it up and around the bottom of the folded-back elevator.

Now the critical part- heat the hinge area so the glue of the top seals to the glue on the bottom covering.  Finish the edges and then finish the rest of the stab.  Do the bottom first so the top overlaps the bottom.

Frank

[Frank v B]

Thank you Michael for the last post.

...back to the fuselage.

Order of work 1) sides (port and starboard, salt and pepper for Andy! ), below the white already completed. 2) the bottom.  Note that usually the bottom is done before the sides but this red covering has a white backing that shows up when sealing heat is applied.  The bottom strip is only to hide the white that shows up.

The fuse bottom has a very gentle curve at the back so it needs very few slits.  The curvature become greater towards the nose so there are more cuts.

Locate the red trim where you want the overlap and tack it at the back, then gently pull at the front so the edge is straight, then tack the front. (photo 1407).  Slowly and gently tack the edge where it overlaps the white.  This edge needs to stay straight.  Once secure at the overlap with the white, heat the rest of the fuse side until it starts to pucker.  Cut slits while stretching the covering a bit. Start securing the overlap at the bottom working from back to front so all overlaps are downwind.
When doing the second side, make sure the slits are staggered. (Photo 1408) Cut them roughly in the center of the slits in the first completed side.

Cut a triangular piece of covering to cover up the exposed white backing ((photo 1409).  Heat seal everything.

The finished fuse is in photo 1410 and a close-up of the rear triangle to cover the white backing is photo 1411.

Next steps. 
- Shrink the wing and tail feathers
- add wing trim colours (red with a splash of yellow, and/or blue).  Colour contrasts make a plane more visible.
- add more colour to the fuselage with either covering or trim tape.
- put the plane together and critique* the colour combo and adjust for effect or visibility.

Frank

* this is when Bruce and Andy pipe up.

[Frank v B]

Adding wash-out to the wing.

Wash-out refers to the twist in the wing so that the outboard end of the wing has the trailing edge raised relative to the centre section of the wing.
A plain Jane explanation of wash-out is that most airfoils stall out at approximately 12 degrees angle of attack.  By adding this twist in the wing, the wing-tips stall out at 13-14 degrees.  When a plane approaches stall speed, you want to make sure the center of the wing stalls first to make sure the tips are still flying.  We are trying to avoid the opposite effect at all cost... wash-in, where the tip's trailing edge is below the leading edge.  If this wing stalls out the plane will flip on its back.

Adding wash-out is a safety issue just to make sure the wing tips stall last.  An interesting note from Keith Shaw is that the flying wings (his King Crimson, Horten and Northrop flying wings) needed 7 degrees of wash-out to fly safely.

To do this, bring the iron up to "shrink" temperature.  Place the center of the wing between your knees and with one hand twist the wing so the trailing edge is higher than the leading edge.  When you achieve this, there will be diagonal folds showing up in the covering.  Keep the twist pressure and shrink the covering.  Turn the wing around and do the opposite side of the same wing half the same way.  Once done, flip the wing around and do the other half, both top and bottom the same way.  This added about 3/8" of wash-out to each wing.

The three photos show the progression:
- photo 1413 shows the wing half before the shrinking starts
- photo 1414 shows the addition of twist.  My thumb is pushing the front tip down, my other fingers are pushing the trailing edge up.  Notice the diagonal folds appearing in this photo.
- photo 1415 shows the twist in the wing before applying the heat.  You can see the diagonal folds in the un-shrunk covering.

[bweaver]

Sorry it took so long to respond to your guidance on solar film hinges.  I have read the instructions over many, many, many times.  Your sketches?  Thanks for the second one.  Still trying to understand it too.... Did @Andy Hoffer  help you write these instructions and sketches?  Perhaps futures sketches could be improved using coloured pencils, pens or crayons.

Katie had to help explain the technique to me.   

@Frank v B have you thought of Youtube??  You could be a star!  Demonstrate the step by step technique in silence.

Can I use this technique to replace broken hinges on my screen door provided I colour match the door and the frame? (Katie would insist on the colour match.)  May have to use mono coat instead of solar film.

[Andy Hoffer]

Adding wash-out to the wing.

To do this...  Place the center of the wing between your knees and with one hand twist the wing

Hey @Frank v B,

I guess this maneuver is most effective when you have to go to the bathroom! 

Andy

[Frank v B]

Andy,

You are so twisted!


Frank

[Frank v B]

Bruce:

re:"Katie had to help explain the technique to me."   

I always thought she was the brains of the operation.  You have now supplied proof!

re: "have you thought of Youtube??  You could be a star!"

You are asking me to mess up another medium.  I am trying to help people, not make them run for cover.

Frank

[Frank v B]

Striping on the wing. 

This is not a scale airplane so nothing to match or mess up.  Sole purpose of the striping is visibility.  If you can't see it, you can't fly it.  This plane will be overpowered so visibility becomes important.

One quote from a friend about 20 years ago comes to mind.  He was a pressman for Heidelberg Presses and knew colours.  When he did a club presentation he said "everyone sees certain colours best"  "What may be perfect for me, may not be perfect for you".

Logic of my colour selection and pattern:
- white makes a plane look bigger on sunny days in spring, summer and fall.  The sun's reflection makes it look bigger and white contrasts with a blue sky in the background. Sucks in winter with grey skies as background.... but that's when Andy flies so no problem for me.
- angled stripping indicates direction (arrow)... "This way... stupid!"
- the most outboard colour must be deep/dark enough to frame the plane. Yellow at the end would make the tip disappear.  Picked red at the end.
- Trap a lighter colour between two darker colours for contrast.
- add a leading edge colour for visibility when coming in for a landing.  To contrast with the trees.

Approach
- do one wing half and do it to completion.  Once happy, copy the pattern for the other wing and the stab/elevator.
- install the wing on the airplane and transfer wing colours and patterns to the fuselage to best effect.

Covering order of things.
- the blue was made 2" wide, the yellow was made 2.5" wide (because "dark" overlaps "light") and the red on the tip was made 4" wide because of the rounded tip.
- tape the inboard end of the aileron in the neutral position with masking tape.  Can't have it flopping around. Photo 1418
- deal with the yellow stripe first since it is lightest colour.  Overlap the aileron and tack it down.  The angle of the stripe was determined by the angle of the wingtip.
- add the blue and overlap the yellow by 1/4" and tack in place.  Add the red tip and overlap it with the yellow so the yellow stripe is exactly 2" wide to match the width of the blue stripe.
- stretch the red over the tips and heat it until it starts to pucker.  Cut slits and stretch it around roughly to where you want to stop. Trim the excess.   Again, start at the trailing edge and work forward.
- now cut the slot in the aileron, remove it and put it aside to finish later. Photo 1420
- cut off the excess red at the tip.  It doesn't have to be straight. Photo 1421
- straighten the bottom of the tip by adding a piece of scrap with at least 1 straight edge.  Tack it at the back, stretch it forward (see photo 1423) and tack it down on the straight edge side first.  Then up the tip towards the top of the wing. The edge is now straight.  Photo 1424
- finish the aileron.  The reason it was attached to the wing was to get the correct angle and placement of the coloured stripes.  Now finish it properly and cut off excess covering.
- add the landing stripe to the leading edge and tack it down.

Ta Da!! Photo 1425

Frank

note: photo 1425 of the finished wing half looks like Cub yellow.  It is actually bright yellow like that shown in photo 1418 but it is a camera flash thing.  Andy will surely follow with an in-depth photographic and technical explanation.  It will keep him busy. .  Please play along with him.

[Frank v B]

Finishing the second half of the wing and the tail feathers.

- copied the first wing pattern onto the other half
- Since the stab is approx. 40% of the span of the wing, I made the stripes on the stab/elevator .8" wide.  Used the folded piece of paper to copy the pattern and spacing from the first half onto the second half.
- put just one red stripe on the top of the fin/rudder.

Next steps
: assemble the plane (wing/stab/fin, glue in the ailerons)
: do the finishing stripes on the fuse (yellow?, blue?)
: RC installation and final assembly.

[Frank v B]

Setting the stab.

The order of setting all the protrusions from the fuselage is:
1) Set the wing to the fuselage when viewed from the top.  Stick a pin in the middle of the top of the fuselage at the very back and then put the wing on the fuselage.  Measure from the trailing edge of each wingtip to the pin at the back.  Adjust until these two measurements are absolutely equal. Drill and install the wing mounting bolt.  If there are two bolts, I drill only one.... just in case I messed up. This assumes you have already found the middle of the wing so one wing is not shorter than the other.
2) Set the wing relatively square to the fuselage when viewed from the front.  If it is off, sand or trim the fuse under the higher wing half until it is relatively square to the fuselage.
3) Set the stab square to the fuselage when viewed from the top by measuring the leading edge of one stab tip to the front and then measuring the other stab tip to the same point at the front.
4) Set the stab so it is parallel to the wing when viewed from the nose.
5) Set the fin/rudder square to the stab....no matter what.

We are now setting the stab.
- The wing is secured in its position with both wing bolts tightened.
- slide the stab in place and measure for squareness (point 3 above).  Once square, stick 4 pins into the stab beside the fuselage, two at the leading edge, two at the trailing edge. Photo 1427
- Slide the whole stab back 1/2" while keeping it square.  The pins are still in place. Photo 1428.  Now take an #11 blade and angle it so the top of the knife is about 30 degrees away from the fuselage.  Score to covering on both sides on the top and both sides on the bottom.
- take the stab out and knife the covering off (top and bottom).  Leave the pins in place. Photo 1430
- test fit the stab by sliding it all the way back into the stab slot in the fuselage using the pins as a guide.  Look at it from the nose and line up the stab with the wing.  They should be absolutely parallel.  If close to parallel, go to the next step.  If cock-eyed, trim one of the fuse sides to make it close.
- pull the stab out, apply epoxy and slide it back in.  The edge of the covering should be 100% covered because we cut it narrow by sliding it back 1/2" and angling the knife when marking it.
- sight the stab from the nose.  Slip in a round toothpick on the low side of the bottom of the stab and push it into the gap until the stab is parallel to the wing. Photo 1432   If so, set aside and let it dry.

Have a beer if you are Wingnutz or a Jamieson's if you are Rob D.

Frank