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Friday, March 25, 2011

Progress this Week

Well I did manage to get some work done this week on 53T.  Most of the progress was in the department of sanding and filling and more sanding.  As mentioned before I put some filler in a few spots on the stringers where we had pulled a little wood up with the fabric.  Hey I guess we just got a little excited tearing off the fabric.  Other places that needed some help were on the wing center section and the coaming around the cockpit.  The epoxy filler (best guess) that was originally used to fillet the transition from the wing to fuselage had gotten soft in a few places and was pretty easy to chip away.  I removed everything that seemed to want to be removed and filled in the gaps with Super-Fill.  The coaming around the cockpit is skinned with Balsa and seemed to have had some sort of epoxy coat over top of it that had chipped off in large areas when removing the fabric.  This also happened on the balsa leading edges on the wing roots.  Anyway I used some super fill in those places too to fill in the holes and keep everything as smooth as possible.  There also is a fairly large area on the right wing root that is sort of flat on top.  It had a bunch of filler there before, some of which came up with the fabric.  So I slopped a bunch of super fill on there in hopes of building it up to a more appropriate wing profile.  Here are a bunch of pictures of various areas in various states of fill.

Visited with a few of the experts about the left wing this week.  Basically there are two options.  Option 1 is to get good measurements on the material that was removed and then figure out the bending stresses through that area using good conservative assumptions.  At max weight and max G if we still have a positive margin on the spar then we'll just smooth it out, varnish, and carry on.  Odd's are this will be the case, I think.

Of course if that is not the case then the only option is to scarf the spar with new spruce.  The repair would look something like this:

That is easy enough, the problem is getting to the spar.  To do that I'd have to cut out three bays of leading edge skin, remove at least a couple sets of cross members, and take out at least a few ribs.  Then scarf the spar and put everything back together.  Not impossible of course.  Harry and Neal have and will continue to do much more complicated repairs.  It's not really anything that I think is outside my abilities either, but i'm not so excited to test those skills that I'm looking for an excuse.  So, hopefully tomorrow I can get some good measurements and start crunching numbers, then go from there.

I spent some time last night doing some more looking around the tail area and trying to visualize and determine the best strategy for the repair before I got too crazy and cutting wood.  I think I have a plane so the next thing I do on the fuselage will probably be to remove the aft bit of each lower longeron along with the lower part of each beam on the vertical stabilizer and some of the plywood sides of the box spar.  Here are a couple pictures of how that area looks now.  I used some rough chisel work previously to remove the bad portion of the aft beam and plywood cover on the aft side as well as the plywood along the inside of the lower longerons.

That's all for now.  Tomorrow is supposed to be club cleanup day at the Gliderport and if we make it out there I plan to return with 373Y.  However the forecast is looking pretty crummy so we'll see if it happens.  The temperature is down for the weekend and beginning of next week but I think I will have the heater operational tomorrow at some point which is fantastic! Of course then I'll need to finish a few spots of sheetrock and insulation in the ceiling and walls.

Sunday, March 20, 2011

One step forward, two steps back

Well we got a great day of work in on 53T today.  We moved the glider over to the new garage on Friday but yesterday we didn't have a chance to get any work done out there.  It was cold, rainy, and windy.  However the wind flipped around to the south today and brought 80 degree temps that could not be resisted!

My first order of business was to get the new top stringer installed.  The old one was removed as it was pretty warped and generally made the glider look lousy.  We ripped a new piece a few weeks ago off a long board of Douglas Fir.  It didn't take too long to get it trimmed to shape to fit nicely into the glider.

I worked out a scheme to get the important parts clamped into place.  Harry and Sue stopped by to look over some stuff on the NG-1.  So that was a bit of a delay as we got one of the NG-1 wings unloaded from its trailer and did some inspecting.  Then I got back to work epoxying the stringer into place.  It went very smoothly with no real issues.  I could tell it was a lot warmer as my cup of epoxy started curing very quickly!  I'm not used to that after working with the West System in colder weather.  Guess I might have to go get some slower hardener...

Here the epoxy has cured, Leah is in the background cleaning all the dirt and grime out of the left wing.  It was a job that was really needed and greatly appreciated.  With some water and Murphy soap the wood is looking brand new!  We did find some additional damage from the mice nest that was in the left wing however.  In wing bays 12, 13, and 14 there is damage to the forward spar.  Apparently mice have a taste for aircraft quality spruce. 

We are not Mickey fans around this house.  We much prefer Goofy since he was a glider pilot.

So here are some pics of the damage.  Will have to check with the local experts on the best repair route for this.  Might have to remove the skin and do some scarfing. We'll see.

This is the damage in Bay 14

Bay 13

and Bay 12

Other work accomplished today was hanging the tail from the ceiling which will make it a lot easier for me to remove the rotten wood back there.  Leah did get the left wing cleaned up really well which is great.  I also did a bunch of cleaning up and sanding where the center section meets the fuselage.  I also added some poly-fil filler to a couple stringers that had gotten damaged when we removed the fabric.  I'll be doing more poly-fil work to fillet the intersection between the wing root and fuselage in the next couple days.  Other main short term goals are to get the rotten wood cleaned out of the tail and get the right wing cleaned up. 

The blog should be much more active now that the glider is here at the house, so keep checking back for updates!

Monday, March 14, 2011

More Scale stuff and update

Well there hasn't been a lot of Cherokee related happenings in my life lately.  We've been slowly working on finishing up the garage.  I still need to get about 3/4 of the insulation in the ceiling and some in the walls.  Big thing remaining is to get a propane tank set up and hooked up to the heater.  We are hoping to get 53T moved over anyway this week though and start to get to work.  It's starting to warm up and going to be in the 60's and 70's later this week.

More updates from the 1/3 scale Cherokee guys.  First up is Creeve's (Charlie) from  His bird is covered and he's working on trim work.  Turns out he is modelling Gary Flandro's full size Cherokee which is the bird that was for sale on Craigslist.  8722E if I remember right.  It will have the full dress indian chief nose art and also a baby albatross style paint job on the rudder.

Here is a picture of the rudder on Gary's full size Cherokee.  Looks cool!  I can't wait to get more pictures from Gary. He reports that he has gotten the wings recovered and is working on painting everything.

Nigel has also been hard at work on his 1/3 model.  He's modelling the New Zealand Cherokee.  Looking good!