Ash,
You're one reason why I take the time to do this build log.  

I built the elevators today.  Very similar to the stabilizer except there is no CF on the LE and TE edges.  The framework is made up of 1/2 x 3/16 9# balsa with a piece of 6# 1.32 balsa in between.  These were glued using medium CA.  The root and tip filler was made up from 5.8# 3/16 sheet and the same 1/32 balsa.  Again glued using medium CA.  The frame work was glued together using Pica Gluit and the 1/8 7.3# ribs were glued in using thin CA.  A hole was punched into each rib to allow air to escape when Monokoting.  The exit holes will be next to the hinges.  

The horn clips are made from 1/8 Lite-Ply and 1/64 plywood.  The 1/8 Lite-Ply is less than the 1/8 O.D. aluminum tubing so the 1/64 ply gets to the right dimension and also adds some strength.  Note the grain of the 1/8 Lite-Ply is vertical.

The location of the horn clips is determined by using some 1/32 plywood pieces 3/4 wide and about 1 long.  These are slipped into the stab TE hinge slots and the elevators are then slip on the extruding plywood.  I marked the location of my offset horn location and filed a small slot in the stab TE to locate and keep the horn in position.  Then the clips were turned upright and 90 degrees to the elevators.  A small mark was then made near the LE of elevator on each side of the clip.  I then disassembled the elevators from the stab and used a 90 degree triangle to draw the cut lines on the elevator.  A quick trip to the jig saw and the clips were ready to glue in.  They were glued to the elevators using thin CA.

I then made up from 1/16 bass wood the "pocket" for my Rabe Rudder horn.  This was glued to the root of the right side elevator on the bottom.  I then capped that off with another piece of 1/16 basswood.  The left elevator same the same treatment sans pocket.

Then then were sanded smooth and are ready to get tapered.  That will happen tomorrow.  I'll use the Perret Bar method.

Each elevator weighs 20 grams as they sit.  I'm expecting them to loose 25% or 5 grams when tapered.  If they come out to 14 or 15 grams each when all done, then they will be right on budget.  I think I can make that weight.

Thanks Crist for this,  the pictures sure clear up what this old man is reading.

...your power system is never going to know there is an airplane behind it!

I've had power systems like that.  That's why they make us put safety cables between the bellcrank and engine in combat planes.

Christ, this is amazing. Thank you for posting the pics. I'm going to take some of your ideas and incorporate what you got going on in my next big plane. I got three 1/2a's to finish up first.

Something like this?

Hee Hee.
  Dean

Yuck!  Hope you are feeling better, Crist.

I make the horn clips just like I did with the elevators.  1/8 Lite-Ply and 1/64 ply laminate.  Glued using medium CA.  The aluminum tubing is glued in using medium CA on both sides.  Then the clips are cut out and the height is made very close to the height of the flap.  The clip location is done by installing the flaps using 1/32 ply for the hinges and centering the flap horn.  The clips are placed on the flaps and their location is marked on each flap.  The flap is removed and a line is drawn from the mark along the root of the flap using a 90 degree triangle to the LE.  The flap is trimmed and the clips are glued in place using medium CA.  The clips are then capped with 1/8 basswood with medium CA.  The 1/8 basswood is notched for the control horn wire.

The flaps LE and TE were sanded round and the the tips were rounded to match the wing tip shape.

Each flap weighs 31 grams.  This is 6 grams over budget for each flap.  12 grams overall with now a 15 gram under budget for the build so far.  These flap are nice and straight and stiff.  Well worth the extra weight "penalty".

Crist, I have been following and enjoying your build.  Great to see you recovering from the flu.

When you are laminating such as the flaps, are you slightly sealing the wood with dope or equivalent prior to epoxy?  It seems that the epoxy can absorb and leave little for the bond, or if more is used, then more weight.

Clever flap layup! Now I'm thinking of variants with thinner skin layers and multiple lightweight 45 degree core layers to trade some bending stiffness for torsional stiffness. Probably not worth the weight and fuss.

I would have automatically used PVA to glue that up, on the basis that the water content evaporates away, presumably leaving slightly less glue weight. That would need to be tested for truth before diverging from your very careful epoxy application, of course.

Are you going to cover the flaps in glass, veil, silkspan or something other?

Christ, i want to try this on the banshee flaps. Is the flap joiner wire OD and aluminum tube ID "the same" for a snug fit? I'm guessing 1/8" stuff?

Yes, I uses 3/32 horn wire on this sized stunter and then I use 1/8 OD aluminum tubing.  It's a slip fit and then combine that with the length of the tubing 1 inch in my case, it's pretty precise.  It allows for the removal of the flaps using a continuous hinge pin.

After another good nap this afternoon and a good hearty supper, I'm feeling better now.  Not the best, but better than the last week or so.  Thanks to everybody's well wishes.

With the flaps out of the way on to the fin and rudder.

The fin is made from 2 pieces of 1/8 6# balsa and 1 pieces of 1/32 7# balsa.  Again a laminated structure with the grain going crosswise on both the fin and rudder.  The rudder is made from some scrap 1/8 7.5# balsa and 1/32 7# balsa.  Again the grain of each piece is going a different direction.  This will create a nice and stiff rudder.  I've had rudders that were made from too soft balsa and they were a pain to deal with.  We're talking a gram or 2 difference.  Besides the rudder seems to always to bumped up against something!

The other rectangular piece are for the rounded fairing on the LE near the fuselage.  This will be glued to the rest of the fin with the grain going the correct way.

Again glued using MGS L285 epoxy.  The entire fin gained a total of 2 grams with the gluing and the rudder still stayed the same (less than 1 gram I figure).

They have been weighted down to cure overnight.

I'm guessing these will make budget if not just a few grams over, we'll see tomorrow.

Crist, If you don't mind me askin', what keeps the bellcrank post from sliding up and down?


Thanks,
MM

It is epoxied to the basswood strips.  When the wing is inserted into the fuselage I use fiberglass on the center section and inside up along the fuselage walls about 3/8 inch.  This FG will also keep it in place.  Stay tuned for details.

Thanks Lee.

No tornadoes, but severe weather.  We are all OK.  North Dallas got hit big time.

Garland: Looks like B-52's bomb it for three days straight.

Ash,
Thank you.

Concerning PVA glue, it's been suspected that it doesn't dry over large areas such as doublers and such.  I use epoxy because I know it will cure properly and will stay that way impervious to moisture and such.  In other words I think it also aids to stabilize the flap and help eliminate any future warping.

The flaps once sanded with 600 grit will then be covered with Monokote.  Another reason I want them as stiff as possible now.

Yes, there are circumstances where PVA doesn't dry inside a laminate, like when vacuum bagged or pressed inside impermeable plattens. I use it for large/wide guitar laminates and it will always dry if there's a way (through the wood pores) for the moisture to get out. Epoxy is definitely better for stability, stiffness and moisture resistance. Worth a few grams penalty, even if there was one.

I bent up the 1/8 MW landing gear this morning and fiddled with some details on the LG covers.  Trying to take care of all the little things now before I start the fuselage and another stabilizer/elevator.

Do you use a jam nut against the ball link? Are those the same 4-40 ball links that Dubro makes?

Thanks,
MM

No jam nut needed with nylon on metal threads.  Like I said before, I use Tom Morris ball links, push rods, and terminal ends.

I finished the elevators tonight except for the tips which will be finished when the stab is done so I can match the tips.  The elevators weigh 23 grams total for both.  About 5 grams lighter than the first set!

Ok, silly question... But I'm asking because I'm cheap! Lol
The aluminium tubes that you used on the first set, are they being reused here? Or will you keep the first set for another plane?

I'll keep the first set and either us it on another plane or sell them/give them away.

Crist, borrowed your method of the weight box.   Looks a lot better than my previous ones.  Thanks.

Good for you.

The fin is sanded and came out 2 grams lighter but it is stronger.  All finished  except for detail sanding.

I made up the fuselage bulkheads.  F2 the motor mount is made from 1/8 copper clad circuit board with the copper etched off.  F3 and F4 are made from 3/32 6# balsa with epoxied 1/64 ply on each side.  F5, F6, F7 is 1/16 6# balsa, F8 F9, F10, F11 is made from 11# 1/16 balsa, and F12 is 6# balsa with 1/64 ply epoxied to the aft side.

I continued to work on the fuselage.  The doublers were glued on using MGS L285 epoxy.  I shimmed the nose of each side up when gluing on the doublers.  

I use 1/64 ply doubler for the tail wheel mount.  These were glued in using medium CA. I also inset 3/32 birch Ply for the adjustable rudder push rod mount.  Also cutout for the stabilizer.

I placed the fuselage sides on the drawing with the tops of each up against each other.  I then draw the bulkhead locations, etc.  I carefully cut out for the wing using a template I created by drawing an outline using R2 as a guide.  Then measured out 1/16 for the wing sheeting.  I then applied a layer of packing tape to each side and cut it out.  

The next picture shows the front end.  I epoxied the 1/4 square x 1/2 long spruce anchor points for the battery tray.  I then used some TE stock to add some extra beef to the motor mount.  I know the grain is going the wrong way and the "fit" isn't perfect, but it will add some strength and also acts as a "guide" when gluing on the motor mount.

Here is a picture of the disconnect and the switch mount on the other side.  These were made from 3/32 birch ply and then inset and doubled over with the 1/64 ply doubler.

Here is a picture of the motor mount doubler and the curve put in when I glued on the 1/64 ply doubler.

I finished building the second stabilizer.  This one has an aspect ratio of 4:1 instead of 4.6:1.

The stabilizer was built pretty much like the first one so no details will be given.

The combined weight of the second stab/elevator is 60 grams verses 63 grams for the first set.  I saved 3 more grams.

This weekend I'll join the fuselage sides and work on getting it ready for the molded top, bottom, and hatch "blocks".

When the fuselage is done and after all the detail sanding is finished, I'll list the weights of each component.

In the picture, the top set is the first set with 4.6:1 and the bottom set is the second set with 4:1.  The second set has 2 inch less span.  27 vs 25.

Hi Crist,

   any chance you can post your weight "budget"?
   That sort of info seems to be hard to find for F2B models.

Thanks,

Pat MacKenzie

Sure.

Have you decided on a paint scheme yet Crist? 

Not exactly.  It'll be red, white, and blue though!

Really??? 

 Just kidding Crist, the build looks great, as clean as it gets!

Wayne,
I know you're busting my chops!

Thanks.