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RB Aero Building Blog

Cockpit painted with Zolatone!

Now the interior of the cockpit is completely coated with Zolatone, which is a very durable industrial coating used in a lot of truck interiors. We used a 50:50 mix of Desert Camo and White Zolatone. We are pretty pleased at the result!



You can see that the seat pans and the seatback panels are also painted with Zolatone. The seatback panels lift out to provide access to our luggage (very small luggage) area. You can see that we have a pretty wide and roomy cockpit (48" wide, which is wider than most small two seat airplanes). Now we can start installing the flight controls (joysticks, flap lever, rudder pedals, pushrods, fuel lines and some wiring.

We are also back to fitting and installing the top and bottom wing skins onto the stubwings and fuel tanks. After the stubwings are completed, we will start assembling the aft fuselage.

Painting the cockpit interior

We are now painting the inside of the cockpit! After weeks of preparation using Super Fil filler and lots of sanding, we are finally starting to paint the cockpit interior. I decided to use a epoxy primer undercoat and will follow up with a 50:50 mix of Desert Camo and white Zolatone.

Here are a couple pictures showing the forward cockpit area with primer.

The fuselage is on its side to make it easier to paint. This view is looking down into
the seating area. The seat support area is covered with paper masking as is the canopy
support area.



This view is a pilot's eye view looking forward.

Next week I will finish painting the area behind the seats with primer and then begin
painting with Zolatone.

Here are a couple of pictures of the cockpit interior showing the Supper Fil filler after it
was applied. The blue stuff is the Super Fil.

 
Looking at center console and                Looking at starboard side with center
the instrument panel.                              console in the foreground.




Wings!

While it has been quite a while since the last blog post, that doesn't mean we haven't been working on the airplane. Since November we have been working on the aft fuel tanks in both stubwings, fitting the top and bottom wing skins on the starboard stubwing and a lot of details in the cockpit area.

This past week we have had some great news regarding the port wing. We have been working with a "little cloud hanging over our heads" for the last six months. We thought that we were going to have to remove and rework the attachment brackets on the port wing. This would have taken several months to perform and presented some serious risks to the wing structure. The great news is that the wing will not require any re-work, our earlier measurements were faulty!  Here are two pics of the port wing being fitted to the stubwing.


Pilot side (port) wing being test fitted to the "stubwing".


It is a long wing!


If your are curious, here is a little more detail regarding our port wing "problem":

In late January, we test fitted both wings onto the fuselage and looked at how well they matched each other. The starboard wing was practically perfect but we had some concerns about the port (pilot) side wing. It appeared to have the leading edge lower and the trailing edge too high. Not only would it not fit correctly with the stubwing, but it appeared that the port wing's angle of incidence would be less than that of the starboard wing. Not a good situation. After much pondering, we decided that we would probably have to remove the top and bottom aluminium mounting brackets from the port wing and add some thin aluminium shims to change the angle slightly. While this sounds simple, it actually would be a complex and difficult job. For one thing, separating the aluminium brackets from the wing spar would require removing 20+  bolts and somehow getting the aluminium to "pop off" the floxed surface without damaging the fiberglass wing spar. Then we would need to redrill the bolt holes, shim the brackets and then re-attach the brackets with new oversized bolts. We would also have to cut away some of the wing's skin in order to get to some of the bolts. If this all went well, the wing's angle of incidence would be correct and if we were lucky, we wouldn't damage or weakened the wing.

We decided to wait on this fix and work on building the two fuel tanks and fit the skins on the other stubwing (starboard) first. We spent the better part of the last 5 months getting the starbord stub wing built. It is currently about ready to be closed up.

Now that we had a pretty good idea of how to build the other stubwing, we decided to re-check how the fit of the port wing. Using a better set up to measure the relative positions of the leading and trailing edges of the stubwings and the port wing, we discovered that the port wing fit much better than we originally thought! The only problem was that the wing is just slightly lower than the starboard wing (like about 0.2") but the angle of incidence was just fine. This is a huge relief, since it means that we will not have to re-work the port wing's bracket after all (which would have required about 2 months of work).

Now we feel confident that we can go ahead and start fitting the port side stubwing skins.

Homage to the "Mockpit"

One of the first projects we did when we starting designing our airplane was to make a mockup of our cockpit. Of course it quickly became known as the "mockpit", but it was no laughing matter! We realized early on that the mockpit was an essential tool in designing a comfortable and functional cockpit. We tested out ideas and dimensions as the design evolved. In this way we knew what the inside of the cockpit would look like and feel like long before we invested time and money into the real thing.

The mockpit began in early 2006 and was modified over the years. Here is a picture of the mockpit with a mockup of the wing alongside it.


We were able to see how easy it was to get into the cockpit by standing on the "wing step". We also measured where the rudder pedals needed to go, as well as how comfortable the seat and backrest were.

Here is a sequence showing Renee getting in and out of the mockpit:

  
1. Step onto wing                                          2. Sit on sill

 
3.  Swing leg into cockpit                             4.  Lower body into seat

 
5.  Ready to go!                                           6.  Getting out, sit on sill


 
7.  One leg out                                             8.  Swinging other leg over sill



Ready to get off the wing.

I should mention that this might not be the best way in and out of the cockpit. As it turns out, the canopy might make it difficult to sit on the sill and swing our legs into the cockpit.  With the canopy in it's upright position, we may just get in by stepping onto the seat cushion and then using the center and side consoles to lower ourselves onto the seat. But the pictures of Renee demonstrate how the mockpit helped us work through "ergonomic issues".


In June of 2007 we added a canopy mockup to the mockpit. We used wire and wood to check out the shape and head room. We were able to determine that a commercially available canopy manufactured by Aircraft Windshield Company of Los Alamitos for the Dragonfly aircraft would work nicely for our project.


The wires helped us see that we would have plenty of head room yet we would have good visibility over the instrument panel. And no, the mockpit is not powered by propane!

Here is what a Dragonfly aircraft looks like:


The canopy that we eventually ordered was an untrimmed version which will give us a slightly taller and bigger canopy than is used on the Dragonfly.


Now that we can sit in the real cockpit, we no longer need to use the mockpit. Since we have had to move it out of the hangar whenever we are working and put it back each day when we are done, we decided it was time to dismantle it.

  
1.Final mockpit configuration  2. Starting to dismantle     3. going....
 
  
4. going....                            5. going......                         6. Gone!

While we won't miss pulling it out and putting it back into the hangar every day, because it played such a important roll, and was our first "tangible" interaction with our future airplane, it will be missed.

Now we can sit in the airplane!

Although it has been some weeks since I have posted anything on the blog, it is not because we haven't been working on the airplane. In fact, we have been very productive these past couple of months. The horizontal stabilizer, elevators and trim-tab are done, and we are ready to start prepping them for paint. We have also been building the seat pans for the cockpit. Here is a picture of the two of us sitting in our cockpit for the very first time!



This is a huge milestone for the project. Up to now, the only way to check out how we will fit and how comfortable we will be in the airplane was by sitting in our "mockpit". Now that the seats are nearly done on  the real thing, we are able to confirm that all the controls will be in the right place and we will be able to reach them while belted in. More on this subject in the next few days!

 

Horizontal Stabilizer and Elevators

We have spent the last couple of weeks putting glass skins on the horizontal stabilizer and attaching the hardware to mount the elevators. I have also been trimming and test fitting the seat supports.




Here is the new stabilizer fully skinned top and bottom with both port and starboard
elevators mounted. A proud Chuck is in the background. While the stabilizer is still large,
it is still a foot or so shorter than the version 1. We also have probably saved 10 or more
pounds.

 
Here I am demonstrating the elevator moving up and down. The mounting brackets worked
 great and smooth. They will be easy to inspect too. Next step is to add counter balances to
 the two elevators and trim and seal the outboard ends of the stabilizer and the two
 elevators.

Over the next few days we will fab the front panel for the seat support assembly and, hopefully, begin installing the supports. Also I plan to finish installing all the brackets attaching the center landing gear mount to the center console.

Here is another cool project being built at Livermore Airport. Our friend Walter has been building a scale replica Sikorsky S-38 amphibian. We also contributed some of our time and expertise as well by making the engine nacelles and fuel tanks. 

  
Almost complete project. The upper wing has been added this week and now final details are being performed in preparation for first flight sometime early next year.



Here is a S38 in flight.



September 1, 2012: Cockpit Bulkhead 51 and Seat Supports

I have been working alone this past weeks since Chuck and Sharon have been on a road trip to Canada. Mainly, I have been making foam and fiberglass parts for the bulkhead (bulkhead51) that supports the coming and the canopy release assembly and also making panels for supporting our seatpans.


Bulkhead 51 Assembly

Here is a drawing of the assembly. 

                           


Here are some pictures of the bulkhead parts as they were being built:

 
Here is the 1/4" foam core for the          Foam core on top of two layers of glass.
panels laid out. Next step: adding     
the fiberglass and resin.     

                   
 
Another picture showing the vacuum      Two layers of glass have been laid on
pump in the foreground.                          top of the foam. Ready to add release
                                                                caul and bleeder (for absorbing the
                                                                excess resin).

 
The lay-up is complete and vacuum          The cured panel is ready to trim.
turned on.

 
The panels are cut out.                          Here is the cross bar getting its last
                                                               layer of glass.



Seat Support Panels


Here is a drawing of the seat support assembly. Below the drawing are pictures of the seat support panels being made.



    
Sanding the rough cut panels                     The panels are getting two layers of glass
to make them 1" thick.                                laid onto one side.


            
All panels now have 2 layers of glass on             All 6 panels have been rough-trimmed.
both sides.


Four of the panels have been cut to match the drawings.




August 16, 2012: New Elevators and Stabilizer

We are continuing our work building new elevators and a new stabilizer for our project. In the last 2 weeks we fiberglassed skins onto the two elevators, cut out the port and starboard horizontal stabilizer, bonded the two halves together to make a one piece stabilizer and finally made mounting hardware for the elevators and stabilizer.

Elevators:


The two new elevator foam cores cut out and ready to cover with fiberglass.



Spreading resin on the lower surface of an elevator. Notice that we have applied a long
strip of duct tape the the rounded (leading) edge. This is to keep the resin from dripping
onto the other side. After wetting the foam, we add resin with microspheres to fill all the
little pockets and irregularities in the foam before laying on the fiberglass. 



Glassing an elevator bottom skin. This new elevator design has a skin of two layers of unidirectional fiberglass. One layer has the fibers running from edge to edge, and the second layer runs diagonally from the forward inboard corner to the aft outboard corner. This will produce a light but stiff elevator. We fiberglassed the bottom skin one day and allowed it to cure. Next we will prep the top surface.




Lower skin of elevator has been cured and trimmed. Ready to prep the top surface for its skin.
 

   
These three views show how the top skin of the elevator's trailing edge is formed. The
reason that we start out with a fat trailing edge is so that the edge doesn't bend or bow
as we glass the top and bottom surfaces. Now that the bottom skin has cured, the edge will be stiff enough so that we can cut off this hunk of foam. Chuck is using a hacksaw blade to cut the polystyrene foam to its approximate final shape.


After the fat aft edge has been cut off, we added duct tape over the area next to the cut so that we can sand it down without digging into the nice smooth foam surface.



Chuck is using a sanding block to do some finishing touches to the rear surface and making it ready to glass. Notice that there is a 1" wide strip (white area at table edge) under his hands where the foam has been completely removed. When we glass this top skin, the top and bottom skins will be bonded together along this aft edge.



The top skin has been added and after it was fully cured, we added a slurry of glass micro spheres and resin ("micro") to the trailing edge (white area on the right). The "micro" will allow us to make the aft edge thin yet stiff.


Stabilizer:


Getting ready to hot-wire cut the horizontal stabilizer's port and starboard foam cores.



Here is the foam core for the port horizontal stabilizer all cut out.




The port and starboard stabilizer halves have been joined together with a slurry of "micro". After curing, we will test fit elevator hinge mounting plates and brackets onto the aft edge which is the flat area along the top.


A pocket has been cut into the foam and a mounting plate is being test-fitted.


Inboard elevator brackets and mounting plates in position.


Another view showing the inboard elevator brackets sitting on the rear edge of the
stabilizer.


Chuck using the Dremel tool to cut out indentations or pockets for the mounting plates to go.


New Elevators!

Several months ago we decided to make a new horizontal stabilizer and elevators. Our first stabilizer was one of the first structures that Chuck designed and we built. Since that time, Chuck has improved the design of the stabilizer and elevators to make them easier to build, easier to attach to the plane and lighter. I told Chuck that I would be willing to remake the stabilizer and elevators if he could save 15 pounds of weight. He says his new design will do just that. I will hold him to it. This past week we used the hot wire to shape new elevators. Next week will will start glassing them and also will cut out the stabilizer. Also this week, we continued to work on the main landing gear center mounts and Chuck made the forward console panels which will mount between the bottom instrument panel and the firewall.

We also ordered our prop from Catto Propellers this week!! We requested that it be white and blue, so we are now commited to the plane being white with yellow and blue trim.


Making the new elevators:


Attaching a template to the end of the polystyrene foam.


A new elevator emerges from the block of foam after cutting with
the hot wire!
 


Elevator core ready to be covered with fiberglass skin.

Landing gear mounts and center console

In the past two weeks we have been working on mounting the landing gear brackets on the fuselage sidewalls and making and installing the center landing gear bracket. This work has turned out to be more complicated than we expected. One of the challenges of building a prototype aircraft from a new design is that we are having to figure out some pretty complex assembly processes so that we don't "paint ourselves into a corner".

So far we are pretty happy about the design of the landing gear mount. We will be able to install and remove the landing gear fairly easily, although I hope that we won't ever need to do that. The other good thing is that the gear mount bolts will be easy to inspect.

Below are some pictures of the landing gear brackets, the center bracket, center console side plates and the fuselage.


  
Starboard side landing gear bracket being         This is a view looking at the starboard outside
test fitted. The seat-back bulkhead is on the      skin. The spar is on the right, the rectangular
left and the wing's main spar is on the right.     hole is where the landing gear leg will go. The
The landing gear legs will go through the           9 or so round holes above it are for the bolts
rectangular hole near the top center of the         that attach the bracket to the inside
image.                                                                  skin of the fuselage.


  
Here is the up-side-down fuselage. The           Here is a view of the fuselage on its side. The 
front end is to the right and the wing spar       two landing gear legs are clamped in position
is sticking straight out. Behind the spar are     and the rear center console and center landing
the two landing gear legs pointing up.             gear brackets are installed.


 
Here is a close-up of the center console and     Installing the forward center consoles. We can
center landing gear bracket.                              hardly wait to get the seats in so that we can
                                                                           sit in the cockpit!