Big changes

 

N494BP has changed!  We initialy started building a KR2-S, however when the fiberglassing of the wings went wrong, I realied it was time to move on to something quicker to build if I wanted to enjoy it with Dad.  

I purchased a Zenith 701 kit and in a few short years, completed it and it is now flying.  The reservation for N494BP was assigned to this aircraft.  

I may one day pick back up on the KR2-S project, but for now the focus is enjoying the Zenith 701.

Summery of 2013 Q1-Q3

I'm behind as usual on the posts.  No surprise there.

Since last year, we complete the foam wing rib and skins, and fiberglassed the entire wing with the help of 4 friends.  Progress has been slow for the last few months as the majority of the work has been sanding and filling on the tops of the wings.  We are using "Superfil" due to its extreemly light weight.  It's expensive at $200 for 3 gallons, but it only weighs 6 lbs per gallon, so on such a weight sensitive airplane, it's worth it.

I had planed on purchasing a great plains engine kit, but with more and more wishy washy answers from greatplains, I have decided to look elseware.  Until we get done flipping the airplane over while sanding it and filling, the engine could not be mounted and would just be sitting there rusting and getting dirty.   Waiting a little longer will probably work out better.

I have some tools now that should make it easier for me to stay caught up on my posts.  Well see how that goes!

Fiberglassing wings complete!

On Saturday morning, we completed fiberglassing the tops of the wings!  The bottom of the wings were completed 7 days earlier and were done in 4 sections per side.  At 4 sections per side, it was not bad at 70 degrees.  As the day got warmer it got harder and harder to work with.  By the final piece, it was a race against time.

This Saturday, the low was 58 degrees and the high was 70.  We completed each side of the wing in just 2 pieces of glass each!




 We were very fortunate to get almost the same crew as the first wing. Jeff + his son Josh, John and Rama.  We did a great job together and it is probably just as well we had one extra person with how big the layups were.  The top came out really nice.  I'm very pleased with how it all turned out.  There is some filling to do, but most of it is due to a little miss shaping in the foam skins.  Thanks to all the volunteers that made it happen.  Jeff, Josh, John and Rama.. And of course Dad, but he's always a key part of the process!

Soon we will be creating the wing tips and cutting out the ailerons.

Bottom of wings fiberglassed

This memorial day weekend we had 3 great volunteers help early Saturday morning to fiberglass the bottoms of the wings.

The first wing went great, but by the time we started working on the second wing, it was clear it was getting too hot.  Both wings came out fine, but the second one will take a little more cleanup and sanding that the first.

We found that 5 people seemed to be the right number of people to accomplish this.  We had 1 person pumping epoxy and making Micro, 2 people wetting out cloth on the templates we made, and then Dad and I placed the fiberglass and applied the peal ply.

I have heard very differing amounts of how much Epoxy was needed.  We decided to start with fresh cans to see what it took.  When we were all done, we had about 1/3 of a gallon left of Resin.  It took roughly 2/3 of a gallon for the bottom of the wing.  10 Yards of KR Cloth and 10 yards of Peal Ply seem to be about right for each side.

Thanks to all my helpers!  Jeff, John, and Rama (and of course Dad!)

Way behind again

We managed to complete the sheeting on the bottom of the airplane at the end of last season, however, we missed the last opportunity to fiberglass the wings.

This winter, we didn't do much with the plane.  We made some decisions, but that's about it.

We were planning on using the Corviar engine we had, but after yet another crank failure, and the rising cost of all the modifications, we have abandoned the Corvair.  I have always wanted to build a Zenith 701, so the corsair will sit in the corner awaiting the next project where it will have a redrive system and the crank should not be a factor.

As it's getting warm out, we are coming around to Fiberglass season.  The bottom and top of the wing are prepped, the templates of the fiberglass to cut out has been made, the majority of the fiberglass is there.

We need one more weekend to cut out the fiberglass and plan for the fiberglass day, and then we are ready!

May 21st - Starting the bottom sheeting

 Today we glued in 1/2" square strips at the join between the spar and the top sheeting.  This creates a lot more surface area to adhear to and also pulls the sheeting down tight on all edges.

We also started on the bottom sheeting.  The inboard panels for the center and front sections are in place, but not all glued down.

As we were about the glue down the bottom leading edge sheeting, we realized that we hadn't installed a Pitot static system yet!

Dad had ordered the tube a while back, so we had the material.  We started uncoiling the tube and making the pitot tube.  We then decided to add the static tube next to it.  We followed plans we found to create the static tube and installed it.

April 29th - Flip Day!

Today, after finishing all the Top wing sheeting, we flipped the plane over to start sheeting the bottom. Here it is just outside the hanger with the flipping jib attached where the firewall will be.

And to the right is the plane in the hanger after the flip.  It only took 2 of us, be it probably would have gone smoother with a little help.

April 9th - More top skins and wing walk

Worked on the pilot side wing walk and glued in the cross braces.  Glued on leading edge ribs.  Next week we will be ready to cover the remaining top skins on the pilot side.

The Passenger side was closed up today after we completed floxing the gear leg to the bracket.  The landing gear is all glued and tightened up.  The top skins are completed other than the trailing edge.

I may go to the airport tomorrow to work on the trailing edges.

April 3rd - More top skin work

Glued in the top foam skin on the passenger side and started gluing in the leading edge ribs.  Discussed canopy options and purchased paint to mark all the bolts.  We will paint a stripe on the bolts and nuts so when we inspect the plane annually, we can tell if anything has come loose.

March 19th - Finishing up the Passenger side wing walk

Today we added the wood that spans across the wooden ribs and cut 3/32" plywood and foam to fit the inboard top wing area.  We also went through and verified all the bolts were tight on the wing attach fittings and the landing gear.  We realized *After* we glued these in that we did not flox the gear leg to the bracket yet..  We'll work on that next week!  We also stopped at our new home improvement store, Menards, while we were out at lunch.  They have all our wing foam and at a cheaper price!  I'm sure the rest of the wing foam will be purchased there soon.

We need to complete the top skins so we can flip the plane and finish the bottom skins.

March 12th - Work started on the Wing Walks

Wing walks are provided to make an area to strong enough to walk on.  Many people think that an airplane must be really strong to fly!  That's not always true.  The wings are made of Foam and fiberglass.  They can withstand a total load of 3G's at 1200 LBS.  That's 3600 LBS of force spread evenly across the surface.  The key phrase is "Evenly across the surface".  The KR2S has 82 Square feet of surface area, so that means 1 square foot of the wing can only support 43 LBS.  A person's shoe applies all your weight in less than 1/2 a square foot.

In the picture, you can see 2 foam ribs and 2 wood ribs closest to the fuselage.

January 30th - Wing Skins

It was the first decent day to get back to work..  We did a bit of cleaning and continued working on the wing skins.  It was still cold, so progress was slow.

The Left and right Top Outer wing skins are complete.  We will need to start working on the wing walk area soon before we can close in the inner part of the wing.

Pilot side Top wing skins

After Lunch we stated cutting the wing skins for the top of the wing.  We found that the foam would not bend around the entire contour of the leading edge ribs.  We cut slots every inch, half the thickness of the foam.  That helped , but it still required some work to bend it around the contour.  Course Drywall screews helped to keep the foam down while the glue was drying.

We ran out of time today to glue in the center sheet of foam, but it will probably get completed one night next week.

Foam Ribs on Pilot Side and Conduit

This morning we cut the wing ribs with our segmented hotwire.  It worked great.  We had a little manual shaping to do with a sanding bar, but it all worked out very well. 

You may notice the white tube in the leading edge foam.  This is a conduit for stobe and Nav light wiring if we decide to add it later.  It is PVC pipe, but it is very light and has an extreemly thin sidewall.  The total weight of a 4 ft section is only 2.6 oz!  The total weight added to the plane is less than 10.4 oz!

The root rib is at -1 degree, and the tip is -1.56 degrees.  The extra few degrees at the tip causes the tips to stall last. That should make the plane not want to drop a wing when it stalls.

Wing Spar Extentions and Ribs

Between 10/7/2010 and 10/24/2010 we added the following Foam wing spar extentions. 

They are standard foam with KR Glass on both sides overlapping the spar by a few inches. We then trimmed out the edges and filled them with Flox. I was amazed at how stong they are!


You may notice the problem with image. The filler we used was Micro, Not Flox! We were able to easily peel out the Micro and redo with Flox.


 
 
 
 
Durring the weekend of 10/24/2010 we glued foam between the spars and on the front and the back for the wing ribs.  We also finished our templates for each end.  We are going to hotwire all the ribs in one pass of the segmented hotwire we built a few weeks back.
 

 
 
 
 

Hotwire issues

I was trying to devise the best way to cut the foam wing ribs for the KR.  There are 5 ribs in the outer wing.  The wing both tapers to a shorter chord at the tip, and changes airfoils completly!  I attempted to plot out the airfoil at each of the 5 locations but had less than perfect results.

After much time was spent working with a spreadsheet and CAD, I decided to see if I could do a hybrid of methods to acheive the wing ribs. 

On the origional KR, The foam was glued in place and a large strait edge sander was used over 2 templates to shape the foam.  This has a few downfalls:

1) Sanding is messy
2) The foam you would have to use is OPEN cell foam.  It requires a coat of micro to seal the cells
3) The foam is not available to me localy so I would have to drive 5 hours, or have some very large pieces of it shipped.

I decided on trying to use the standard Polystyreen foam and a long hotwire.  Unfortunatly, the hot wire would have to be so long that I was sure I did not have a way to power it.  I wondered if I could Segment the wire by making the electricity "Jump" across parts of the hotwire by adding a larger wire in some segments giving the electricty a path with a lot less resistance.

Here is our attempt using our long bow and a 14 gauge wire with aligator clips:



As you can see, It worked..  So, it was time to make a looong bow that could span all 5 wing ribs on the outer spars which as 90" long.

Here is the final product:



Now I just have to hurry and finish the foam spar extensions before it gets to cold to fiberglass!  I hope to have wing ribs in place and shaped by Halloween!

Aileron cables completed!

Over the past few nights I have managed to finish the aileron cables.  They don't move as smooth as I would like.  I suspect there is a pivot point not moving smoothly. I will be looking into the problem tomorrow

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Elevator cable routing preparation

This week I was able to cut the rear horizontal stabilizer to make clearance for the bottom elevator cable and glued in an extra wedge for the bolts to bolt against. we also drilled and tapped one end of the elevator push rod.

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It's official. It's 8 ft wide....

This past weekend we reviewed what we would like to do next and decided to glue in the Horizontal Stabilizer so we can finish the Elevator controls next weekend.  The tail is 8ft wide rather than the 6 ft wide the plans calls for, so it's not very trailer-able and will barely fit through any garage door now.  We could not do much since we did not want to disturb the plane while the glue was drying, so we did not get much done.  We did a little cleanup and worked on a 23cc Weed Whacker engine I had laying around in hopes of using it for a giant scale model airplane engine.

It's Been a while.....

As usual, I'm a bit behind in blogging.  It's been a summer of painting, sanding, filling, sanding, filling, sanding, filling.

The Horizontal Stabilizer has had several coats of filler on it and sanded many times.  When the airport is so far away, it's difficult to make the 25 min drive each way for a 10 minute session of sanding and adding a coat.  A word of advice for other builders would be to keep it at home as long as possible.  I'm considering moving it back home once the wings are completed and can be removed so the plane fits easily in the 2 car garage.

The other things we have been working on are the controls and the seat.  I've found that there is a lot of making a part 2, 3 or even 4 times.  This summer we created our second seat with some help from Ken Jones.  He had some left over fiberglass that was terrific for the seat.  It was very heavy and one layer on each side can support my weight as I enter and exit the plane.  We will need to load test it to 3G's  (2 people at 200 lbs each, *3 = 1200 lbs of static load!)   I think it may need one more layer, but it's going to work out.

After the seat was ready, it was time to work on the first control surface.  The Rudder.  The Rudder pedals have been completed for a while and were installed.  They now have cables attached and move the rudders.  I have tested them by putting all the force my legs can push on each pedal and nothing has failed.  I would like my welds to look more professional, but I'm confident they will work.

I have been concentrating on learning things that will make me more efficient in ordering materials and in planning.  I have been  learning DeltaCad after seeing the many drawings my dad has made for the airplane.  I did not understand how he made some of the drawings and while I trusted my dad, I wanted to understand.  As much as I appreciate his help, I want to know I could do it if he wasn't there.

With that in mind, I loaded DeltaCad's free 30 day trial and ran through the tutorials.  I have since drawn my kitchen floor, my hanger, and 1/5th scale wing ribs from the AS5048 Airfoil Coordinates. If you're interest in learning a very easy to use 2D cad program, check out http://www.deltacad.com .   There is a 30 day free trial, after which it costs $40.  The tutorial will walk you through everything you need to know.

We Went to "SloshKosh" 2010 and I was personally very disappointed.  It really should have been canceled.  The only good things I got out of it was spending some time with my dad, and getting started learning to Gas weld with Oxy-Acetylene.  I have always heard how difficult it is but I was surprised that I did not find it that difficult.  I may be able to make my own custom length engine mount after all.