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Being a stealth pilot is one of the most labor-intensive and time-constrained types of flying that I know. We have very strict timing constraints... For example, during a bomb competition in training in the US, I dropped a weapon that landed 0.02 seconds from the desired time, and finished third!
(Lt.Col. Miles Pound, USAF)
 
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Project Log
Aircraft Construction - Pitts 14 Prototype

Construction Begins May 2003
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Article by Mike Whaley
 
Construction begins on the Pitts 14 prototype in early May 2003. Curtis came to the shop for a week as his Model 14 drawings became structure for the first time. Jigs were completed for the fuselage side sub-assemblies and tail surfaces. Tubing nibbler pattern templates were completed for all tubes in the fuselage. The fuselage sides were tack welded together. The Model 14 prototype was under way....


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Curtis smiles for the camera as we begin the initial prototype construction of the Pitts Model 14. Curtis has been designing best-of-breed aerobatic biplanes for more than 60 years.  
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The fuselage side frame subassemblies are laid out on a jig built on a flat baseboard, similar to many other tube-built aircraft. Hardwood blocks are cut in quantity and pre-drilled in advance for the screws which will anchor them to the baseboard. The blocks locate each tube in the side structure and allow the frame subassembly to be tack welded.  
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There are lots of little details at this early stage. Paul Goetsch lays the foundation of the Model 14 fuselage. The starboard and port sides are identical and use the same jig.  

Fuselage Basic Structure June 2003
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Article by Mike Whaley
 
The prototype fuselage was built during the month of June. Curtis returned late in the month to continue the refinement of the design. Things are progressing well... the fuselage is recognizable and on track for an Oshkosh debut.


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The fuselage box is taking shape. The completed side panels are jigged level and plumb. The longerons are heated and bent inward at two stations to join at the tailpost.  
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Many clusters are tack-welded until the basic structure is complete, then they're finish-welded in schedule order.  
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Here is the cross-truss for the new oleo gear, oriented inline with the load.  
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Curtis isn't one to just sit back and watch... here he is laying out a full size template for a construction jig. His pragmatic approach to layout and construction has been optimized over the development of many prototype aircraft.  
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Mark Eckenrod tacking-up the fuselage while Curtis works the design. It is an honor to work so closely in the prototype development, and to learn a from his lifetime of experience.  
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Rule Number 1 in airframe construction: Do not weld yourself inside the fuselage!  
   

Fuselage Basic Structure Completed, Engine Arrives, Steve Culp Helps Out July 2003
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Article by Mike Whaley
 
The first M14P engine from George Coy arrived in mid July, although shipping caused failure to the structure attaching the motor to the pallet (a seemingly very sturdy structure.) Fortunately, damage to the engine is minimal so we are able to forge ahead. Steve Culp (creator of the Culp Special) arrives for a week or so to help out, and among other things, he welds up the new motor mount. By the 22nd, the fuselage had gear legs, the whole structure had temporary paint to protect it from the weather, the engine had been mounted, seat backs and floor panels were installed, and the prototype was put on a trailer and wrapped up ready for the long drive to Oshkosh. Several folks have already climbed in and made airplane noises.


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The Rusky engine awaiting installation on the fuselage. Kinda like a good Ukrainian woman... "Strong like buuull - smart like traktor"...  
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Mike Hughes, Andy Friend and Paul Goetsch hang the engine. The bolts just slide in.  
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Paul honors the timeless tradition of getting in and trying things on for size at the earliest opportunity.  
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July 23, 2003: The Model 14's humble beginnings on the trailer to Oshkosh.  
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A layer of stretch wrap, then one of blankets, then a top coat of stretch wrap. Snug as a bug in a rug.  
     

Pitts Model 14 Introduced at Oshkosh July 2003
(Week 4)

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Links:
 http://www.airventure.org/  http://www.steenaero.com/
 
Article by Mike Whaley
 
The Pitts Model 14 is announced at Oshkosh, with intense interest shown in Curtis' latest design. The fuselage is displayed and we display computer renderings of how it will look. This website is launched simultaneously, and is well received.


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July 30, 2003: The Model 14 prototype proves a popular attraction at Steen's booth at AirVenture.  
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There were large throngs of people around the booth for most of the week. They were asking a lot of good questions about the Model 14 and our other products as well. Oshkosh is always a great chance to visit with old friends and make new ones!  
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David Stone (left) and Mark Eckenrod (right) help answer the many customer questions during the week.  

Curtis Visits to Continue the Design, Wing Construction Begins August 2003
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Article by Mike Whaley
 
Curtis visited us after Oshkosh to continue working through the details of the design. He was tickled to see the progress and the fuselage sitting on the gear.

The wing construction was started. Began producing CNC rib jigs and built a number of ribs.


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August 15: Curtis with the prototype fuselage, just after Oshkosh... a proud papa if we ever saw one!  
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The the seat backs and floorboards are temporary to get a feel for seat geometeries and ergonometrics.  
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The mount for the removable vertical fin. Different, interchangeable profiles of the vertical and horizontal surfaces will be offered in the future, to suit different applications and aesthetics.  

Wing Construction Underway September 2003
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Article by Mike Whaley
 
Taking long strides on the lower wing construction. Built jigs for the wingtip bows, and produced the first set of bows. Well along with rib construction. During the process, revised plans in CAD as small issues were discovered (mostly interference tweaks, nothing major.)


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You need a LOT of clamps to build wooden airplane wings! Here, laminated wingtip bows and laminated capstrips are being formed. (Later, we started forming the capstrips as sheets, and sawing them into strips afterwards.)  
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John Hollister holds a rib in the Steen Aero woodshop... John does really nice work.  

Lower Wing Basic Construction October 2003
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Article by Mike Whaley
 
Completed the lower wing spars and began to assemble the lower wings. Lots of progress made, including minor rework as the assembly revealed hidden issues. Most of these issues were optimizations for ease of construction and to provide required clearances for hardware and fittings. The CAD plans have been revised as the changes were made to ensure the master plans stay current. The basic lower wing structure is substantially complete at this point.


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The two lower wings are assembled (sans epoxy sealer) while we look at the fit of everything. Many minor tweaks in the details were made during the initial construction.  
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One thing is for certain... these wings are stout! The I-Strut to wing-root span is very short.  

Lower Wing Details and First Fuselage Formers November 2003
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Article by Mike Whaley
 
The lower wings were worked on during early November, with a lot of progress being made. The tip bows were installed, as was a lot of secondary structure, gussets, sheeting, wingtip foam, etc. Minor revisions have been made to many parts to improve the final product. On November 7th, Paul took the wing to the Pitts Fly-in in Ozark AL, where a lot of folks got to see it. Comments were favorable. After the fly-in, construction continued. We also began work on the fuselage shape, starting with creating templates for the formers along the fuselage and the turtledeck.


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The wing trailing edge on either end of the aileron wells is completely boxed with plywood for the required stiffness.  
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Here, J.C. Taylor seals the wood inside the box with epoxy varnish before it is enclosed. You can never be too careful with wooden wings when it comes to moisture.  
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The finished aileron bay end. It is now able to support the fabric and to anchor the trailing edge.  
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This shows the shape of the training edge aluminum... this is classical wood and fabric construction.  
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The underside of the wingwalk shows several stiffeners and is covered with plywood.  
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Plywood plates support compression loads within the wing. Some are full sheets, some can contain lightening holes where the loads are reduced. CNC machining makes the profiling of these plates an "art to part" process.  
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These spar doublers have been shaped so as to prevent concentrating stresses in one area of the spar.  
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This compression rib is an example of the kind of tweaks we've been making as we go along. This pushrod cutout will be re-shaped on production parts to have nice symmetrical arcs that don't look "chopped off" on the bottom. This is a cosmetic issue and will cause no compromises on the prototype airplane.  
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The wing attach plates installed on the forward spar.  
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The wingwalk bay before the deck plywood is installed. Another view of the wing attach brackets.  
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The wingtip bow is attached. Rubber bands and tiny brads can be a real help in glueing up (the brads are removed later.)  
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J.C. Taylor (left) and John Hollister install reinforcements to the wingtip bow. The fabric and ground handling both put a lot of stress on this structure, so it needs to be strong.  
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The prototype wingtip is shaped using foam. The prototype woll be used to pull off a mold form which will be used to construct fiberglass wingtips for the production birds.  
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The spar cap raises the surface of the spar to provide for a solid glue face between the spar and the plywood leading edge. This forms a strong "D-tube" structure.  
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A lower wing is all wrapped up for Paul to take to the big Pitts Fly-In in Ozark, AL. Everyone seemed to really enjoy the "work-in-progress".  
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Fiberboard was used to make initial templates for the firewall and fuselage forming bulkheads. This process takes critical effort and defines much about how the airplane will look when finished. (It also breaks-trail and makes things easy for our builders!) Barrett Brummett has broad experience building aerobatic biplanes, and he did a super job getting the profiles just right.  

Fuselage Formers, Skin and Wing Details December 2003
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Article by Mike Whaley
 
To assist with creating the side formers and the side panels, the lower wings and tail were attached to the fuselage while posterboard templates for the side panels were attached to work out the panels and how they would overlap and intersect adjoining structure. Suspending an old Yak cowl in front for fun really made it look like a Golden Age racing monoplane! Curtis visited early in the month to make progress on the upper wing center section and cabane system.


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Posterboard is used to work out the panel boundries and shape fuselage skin will take. It's a lot cheaper to work in posterboard than in 2024-T3.  
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The penetrations for gear legs, cabane tubing, etc. all present challenges. The goal here is elegant symplicity, ease of construction, and low weight.  
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With the lower wings and side panel templates temporarily mounted (not to mention the spoof Yakolev cowl), it really looks like a Golden Age racer!  
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The gang gathers round the plane for some hangar flying. Jere and Paul are behind the wing, with Curtis and Chris standing in front. When Curtis walked into the high-bay and saw the shape and form for the first time, he just beamed.  
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The wingtip bow carries has a lot of stress both from the fabric and from ground handling. Here is the tip brace truss structure.  
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J.C., Barrett and John conference on the wingtip.  
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The fuselage former bulkheads have been made in aluminum and fitted. Production parts will be cut on the waterjet and will incorporate lightening holes.  
 

Fuselage Side Panels and Upper Wing Construction January 2004
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Article by Mike Whaley
 
We are happy with the fuselage skin design. It has been a lot of work to get it right, but the benefit to our builders will be great. The side panels are aluminum and are piano-hinged along the top longeron and are secured along the sides and bottom with camlocks. There are three panels on each side (four including the cowling panels forward of the firewall), and each may be opened independently. This allows maximum maintenance access to all internal systems.

The bottom fuselage panels are also easily removable with fasteners in the conventional manner, since most inspection and maintenance tasks can be accomplished through the side panels. The section of the fuselage aft of the rear cockpit will be covered in fabric, with removable inspection plates installed as necessary.

Part of the fuselage panel design incorporates a fiberglass wing-root faring between the fuselage, the lower wing, and the landing gear leg.

As we wrapped up construction details on the lower wings, including shaping the foam wingtips and installing control linkages, we have begun primary construction of the upper wing panels. They are nearly identical to the lower wings, and differ only in the details.


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The fuse formers have been completed. The rear seat headrest and support are dummy templates to establish the shape of the turtledeck.  
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If you look closely, you can see the piano-type hinges installed along the upper longeron. These panels will provide quick and complete access to the entire interior!  
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The fuse takes shape, this time in the final metal. The panel transitions are smooth, natural, and elegant. Cudos to Barrett. He is a innovative builder with deep experience.  
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Preliminary fitting of the prototype panels with clecos. Subsequently, the bottom edges were trimmed to overlap the wing root faring.  
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The cowling air exhaust will exit through this deep channel in the bottom of the fuselage skin.  
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The formers are fastened to angle brackets which are welded onto the airframe. This station is actually the firewall, which is also attached at the four engine mounting spools.  
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This shot shows how the side panels will allow you to inspect and maintain interior components of the cockpit.  
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The panels are secured with camlock fasteners. You will not need to open one panel in order to be able to open the next one, as they do not overlap.  
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Here, the panels are being rough trimmed to clear the wing. They will be trimmed further to overlap the fiberglas wing-root farings between the fuselage and wing.  
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Another view of the panel initial rough trim around the wing.  
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These are rolled aluminum hinges attached to the upper edge of a side panel with rivets. Extruded piano hinges, often used on flight control surfaces, are stronger (since they're molded as one piece and thus don't have the gap in the loop) but they cost a great deal more. For this particular application, rolled hinges are the right choice.  
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This photo was taken with the camera placed where the pilot's head will be. The visibility with the fuselage will be good. Taxiing visibility will be typical of radial engine biplanes.  
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These are the 4130 wing-attach plates which thru-bolt onto either side of the butts of the upper wing spars where they attach to the center wing section.  
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The lower wing has been fitted and rigged to the proper dihedral in preparation for shaping the mold pattern of the fiberglass wing-root faring.  
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Foam is glued and formed to the wingtip profile. The prototype will be used to extract mold forms for fiberglas wingtips to be used on customer aircraft. The wingtip shape will be enforced using a special expanding foam. On the prototype, the foam will be covered with light fiberglass cloth for skin strength and dent resistance under the fabric.  
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The aileron bellcrank assembly has been temporarily put into place in the lower wing.  
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A portion of our busy shop... while Barrett Brummet and Phil Everette work on the fuselage formers, John Hollister has been finishing up details on the lower wings and building the uppers.  
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The upper wing ribs have been placed onto the spars, but most have not yet been glued in place.  
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The ends of the aileron bays have double ribs for stiffness, just like the lower wing. The space between the two ribs will be fully boxed with 1/16" plywood.  
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This shows the hardwod blocks that the internal drag/anti-drag wires land on. The blocks and rib cutouts are being treaked slightly on production aircraft to allow for easier construction.  
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Production kits will have modified nose ribs for use where there are wire blocks, in which the plywood will extend into the space between the wire mounting blocks. On the prototype, we inserted filler blocks to occupy this space... only a minor inconvenience.  
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The ribs are being tacked into place with T-88. Later, they will be set on end and the ribs will be fillet-glued to the spars.  
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John Hollister works on the upper right wing panel. The wings are well along.  
 

Wing-Root Fairings, Fuselage Skin Panels, and Upper Wing February 2004
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Article by Mike Whaley
 
February saw us continuing with the construction of the fuselage skin panels and the creation of fiberglass wing-root fairings. These were built by attaching the lower wings and making a very rough sub-frame to support the fillet using blue foam and scrap plywood. The wooden sheeting in the wing root area was first covered with a layer of duct tape in order to protect it, then modeling clay (many pounds of it) was applied to shape the fillet. The clay is much easier to work after microwaving... about 3 minutes on "high" seemed about right for a hand-sized block of clay.

After applying clay and rough sculpting, we formed the right shape... a bit longer and it was all smoothed out. When it was "just right", we applied layers of fiberglass cloth over the clay to build up the prototype wing fairing and subsequent mold form. This not only covers the wing root area, but extends forward as well to fair in the area where the landing gear leg meets the fuselage.

After the epoxy cured, we removed the fiberglass, cleaned up the edges, sanded it a bit, and were pleased with the results. The fairing is attached to the fuselage via quick-release fasteners, which are anchored to the aluminum side formers. We then carefully trimmed the hinged aluminum side panels to overlap the fairings over an aluminum angle stiffener.

On the inside of the cockpit, we installed small aluminum panels to cover the wing root area. It will be easy to get into this area when needed for inspection, but most of the time you won't want or need to see it.

The lower edges of the side panels anchor to the fiberglass fillet using camlocks, while the edges of the panels anchor to the aluminum fuselage formers using the same type of fittings. The fiberglass and interior pieces also anchor to the formers in the same way. In most areas, there is a sandwich with the side panel and faring being held with a common connector.

In the end, we have achieved the goal of easy maintenance access, ease of construction, and low weight, while also making for a neat and attractive installation.

The design allows the panels and fairings to be factory supplied with final trim on two sides done at installation. The sheet metal is one of the more labor intensive areas of construction, and we aim to greatly reduce this effort for builders.

In February we also began the process of building the upper wings. These are nearly identical to the lower wings; they differ in hardware and a few details. We have also been working on the layout of the upper wing center section, building a quick mockup with pine spars to ensure that the wing fuel tank and fittings all work out as expected.

As this is written (mid March) we're only a month away from Sun N Fun 2004. We will have the Model 14 prototype there, of course.

We are trying to make as much progress as possible, though the days before SNF are hectic to say the least. We pack up all sorts of displays, our tents, and get set up so that most of the company plus family members can camp comfortably in Lakeland for a week and a half... no small undertaking.

As we're fond of telling people, the prototype will be done on Tuesday - we leave the question of which Tuesday a bit open to speculation.


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Prior to making the wing fairings, the side panels were rough trimmed to clear the wing root to enable the panels to close.  
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Each panel is fastened down separately using flush quarter-turn fasteners.  
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Blue foam and scrap wood was used to provide a solid support base for the clay.  
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Here you can see the thin plywood frame that gave the clay a solid base foundation. The wood was simply secured with duct tape to the aluminum skin.  
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Barrett Brummett (left) and Paul Goetsch apply the first layers of modeling clay.  
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Steen president Paul Goetsch applies clay to the wing root area. Each block of clay was heated in the microwave for about 3 minutes to soften it.  
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The clay mold is beginning to take shape.  
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Preliminary smoothing of the clay.  
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You can use any handy object to help you shape the clay.  
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The clay is sculpted to create a smooth fairing over both the wing root and the landing gear/fuselage junction.  
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The clay has been shaped and smoothed in preparation for covering it with fiberglass. The fiberglass will provide the farings for the protorype, and will be used to "take-off" the final production molds.  
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Barrett performs an annual inspection on the microwave.  
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The clay sticks to the underside just fine, as long as the supporting framework is secure.  
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The landing gear leg / fuselage junction is also faired in an integrated system.  
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The rear of the mold, before final surfacing.  
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The trailing edge section ready for glass.  
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The clay completely fills the gap between the wing and fuselage skin.  
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The blue line marks the planned edge of the exposed fiberglass. It must overlap this line in order to allow room to underlap the side panels and fasteners.  
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John Hollister (left) and Barrett Brummet apply fiberglass cloth.  
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The first layer of fiberglass cloth has been applied and brushed down.  
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The fiberglass is built up in layers, with care taken to avoid air bubbles.  
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Several layers of fiberglass cloth are applied.  
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The fuselage/landing gear junction is also covered with a fairing.  
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The rear edge is clamped to ensure that the top and bottom layers of fiberglass are firmly joined together.  
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There is still a bit more finishing needed, but the basic shape has been created.  
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The fairing has been trimmed and separated into sections.  
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This will provide an elegant, smooth transition from the gear leg into the wing-root faring.  
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Here you can see the front section of the fairing.  
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The trailing edge fairing really gives an elegant shape.  
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This is the wing root area beside the rear seat. The fairing is installed, but it hasn't yet had the fasteners installed to attach it to the lower edge of the side panel.  
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The side panels are trimmed to overlap the outside of the fiberglass fairing.  
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Here you can see the interior panels which close-out the wing root from the inside of the cockpit.  
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Here we are fitting the interior panels to the inside of the fairing.  
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Clecos hold the interior panels to the fairing while the fasteners are installed.  
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Here you can see the large channel for coolant air exit.  
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John Hollister shows us the upper-wing center-section spar assemblies.  
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Some of the attach fittings that join the upper wing's outer panels to the center section.  
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John locates ribs during construction of the upper wing panels.  
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The upper wing panels are nearly identical to the lower. This alows all four wings to be built on ONE short wing table if necessary.  
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Not all of the ribs are glued in yet, pending final checks.  

Fuselage Side Panels, Wing Rigging, Engine Arrives March 2004
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Article by Mike Whaley
 
Curtis paid us a visit at the beginning of March. Work continued on the side panels, mostly, finishing touches. The inner panels which protect the wing root area and provide for a more aesthetically-pleasing appearance in the cockpit area came out well.

We continued to make a lot of progress on the wings, finishing the major structural components. The construction style will be familiar to those who are familiar with the Skybolt or Pitts Special construction methods, though there are some neat features embedded into the design. Obviously, our goal is to make the construction process as easy as possible and we have developed a few things to facilitate this along the way.

On March 16th, we received a present... the 400hp M-14PF engine arrived, courtesy of our friend George Coy. Upon opening the box, we found that the engine had leaked about a gallon of oil into the bottom of the packaging materials... well, at least we know it's well lubricated! The engine comes with seals, spark plugs, and even a tool kit with some rather unusual-looking tools. Our engine is an electric start model. Ours even had the original Soviet Union-era nameplate still attached (these engines are generally made in Russia or the Soviet Union, and are refurbished in Romania before being exported.)

Some folks like the air start version, but we feel that it would probably be a bit more practical to have the electric-start version. If you are at any airport in the US and get caught with a dead battery, you can almost certainly find DC power. You may have a bit more difficulty in finding a bottle of compressed air equipped with a connector you can use. (Some of the guys with air-start M14's carry a whole kit of various adapters for this purpose.) Of course, if you fly in Eastern Europe or Russia, it's entirely possible that it's easier to find compressed air at your airport than DC electrical power! We expect to see both flavors of starting systems used successfully on the Model 14.

We reached an exciting milestone on March 25 when we mounted all of the wings to the airplane. For the first time, all the major components were connected and it looked like a whole airplane! The impression it gives is a tall, stout, beefy biplane. The plane has a sort of "presence" all its own. Curtis sure looked like a proud papa watching his latest plane come together in a recognizable form.

Rigging the wings was an interesting process. First, a long digital level was used to get the fuselage square, both fore-aft and left-right (pitch and roll axes.) Then the lower wings were connected, and supported by wooden stands. Then the cabanes were attached, followed by the center section. The center section required a sheet of plywood to be clamped to it for support, since it wasn't yet finished to the point where it would be fully dimensionally stable. To help with the alignment, plumb lines were attached to the mounting screws at the top of the cabanes. There are several alignment issues going on at once... the structure can sway left-right, fore-aft, or any combination. In addition, if it moves one way, it will be skewed and misaligned in another direction. Since the cabanes aren't a parallelogram, if the center section moves left or right, then one side ends up higher than the other. This is one place a digital level is vital! In essence, we had to figure out where each part should be, adjust it to get there, and then re-adjust everything else to get them back where they were supposed to be. As the wires were installed and tightenened up, it got progressively easier until we reached the point that the center section was secured into the proper place all around.

Once the center section was secured, then the upper wing panels were attached and supported on wooden stands. The landing wires were added first, which supported the lower wings, and then the I-struts were added which in turn held up the upper wings. For many of these we used some spare steel tie rods we had in the shop, which is why not all the linkages in the photos are the shiny stainless Bruntons wires which we will ultimately install on the finished plane. (Yes, we have to buy the wires from the factory too, so we wanted to work the dimensions out first!) At this point, it was a matter of just adjusting things until everything worked out.

In addition to refining the plans and parts as we go along in order to smooth the construction process, we have been developing a few tools and fixtures to aid with the more difficult tasks. In the photos you can see two such tools. The first is an alignment jig used to drill the critical I-strut attachment holes. Obviously, drilling quarter-inch holes vertically through your precious wing spars can be a bit nerve-wracking, but with a good fixture it can be made a lot less stressful.

This jig is actually very simple in concept and operation. The correct location of the top and bottom of each hole is marked on the top and bottom surface of the spar. The jig, which is essentially just a tube with a cutout for the spar and some structure to hold it in alignment, is clamped onto the spar with C-clamps (using scrap wood blocks to protect the spar from the clamps, of course.) Then you sight down the tube to align the top and bottom exactly with your marks, and tighten the clamps to hold it firmly in place. We used folded paper shims for the fine adjustments. When it is just right, you can drill your hole with confidence. This was a 2 or 3 person operation, in part just because you want to be sure that someone is holding onto the heavy steel jig while you're looking up at it from the bottom, lest it slip and smash your head as it falls to the ground. Having this happen will cost you many brownie points with the spouse, as it could easily send you to the emergency room and deplete your airplane building budget!

We also developed a jig to solve an age-old question: how do you align the holes for the drag and anti-drag wires inside the wings? Many folks have used the TLAR method (That Looks About Right) with varying degrees of success... you can find many planes with wallowed-out holes or slightly-bent wires as a result of this method. Obviously, this isn't up to Steen's high standards. Our solution involves a universal drilling jig (it will work on almost any simlar airplane) that is extensible lengthwise, with two drill alignment guides at each end. Each end also has an adjustment screw to precisely set the height of the drill guide tube at each end. (Essentially, the jig is just a mechanism whereby two tubes - the drill guides - are held precisely in-line with each other regardless of their distance apart, with provisions made to help hold them in place against the airframe. This ensures that the drill bit will always point exactly at the far hole.) To use it, you just mark where the holes should be (on the maple wire blocks) and place each end of the jig where the ends of the wire will go. You then lock in the length of the jig to match, and then make fine adjustments to the hole's vertical placement on the maple block. One person holds one end in place, while the other one drills the hole on the opposite side. In places where the wire will connect to a tab on the interior of the wing, you just have to hold that end of the jig against the tab.

The results obtained with this wire-drilling jig were excellent! In roughly one hour, we had made all the holes for the drag wires! One thing you have to remember is that the wires have to be staggered vertically so that they can cross each other in the middle, ideally they will just barely touch (if they touch at all.)

Sun 'N Fun preparations started to really pick up during March, but so did the energy level. We were very motivated to get the plane ready to show, knowing that we had a large audience waiting to see it. While we had it assembled, we even tested out the best way to fit it into the tent.


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Curtis and Barrett discuss the Model 14.  
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The interior panels really clean up the cockpit area.  
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The panels and fairings really help smooth out the lines of the plane.  
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This gives an idea of the excellent access the side panels will permit.  
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The wing is coming along nicely.  
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This is the crate the engine arrived in.  
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A genuine Soviet -made aircraft engine tool!  
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Once upon a time, the American aerobatic team flew Pitts Specials and completely embarassed the Soviet aerospace giants in competition. Now, the Russian engines are powering the latest Pitts.  
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Just like a radial should, it leaked oil into the crate. It was just practicing for the real thing!  
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What a beautiful sight!  
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They even give you a set of tools to keep handy... very practical.  
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Curtis supervises the initial rigging of the center section.  
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We used plumb lines from the mounting bolts to help align everything. This was a tedious, yet enjoyable, process.  
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The attach points for the cabanes are quite beefy.  
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Our waterjet cutter produces some beautiful hardware!  
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This is where the left foremost cabane attaches to the fuselage.  
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Finally... we have a real live biplane! This was an exciting moment for us all.  
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The landing wires supported the lower wing while the rest of the rigging was installed.  
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The upper wing joint.  
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This is the simple jig we created to align and drill the I-strut attach holes which go vertically through the spar.  
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Here's the I-strut drilling jig in use. You have to use shims and wiggle it around a bit until it's lined up just right.  
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The view down the drill tube.  
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Paul checks alignment before drilling.  
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This is a spare Skybolt canopy... it gives an idea of the canopy setup, though the Model 14 setup will be a different shape and setup.  
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While we had it together, we worked on how we would fit it under the tent at Sun 'N Fun.  
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The drag/anti-drag wire drilling fixture. It's adjustable in length. The drill tubes remain aligned regardless of other adjustments.  
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Here is a closeup of the end, showing the adjustable standoff used to brace it against the wire blocks.  
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If you're connecting one end to a tab inside the wing, just hold that end up to the tab.  
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Paul drills a hole in a wire block while John holds the far end firmly onto the wire attach tab.  
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Let the sawdust fly!  
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It's important to remember to stagger the wires vertically so they will pass each other. It really doesn't matter which one is high or low, but be consistent.  
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Paul measures in order to drill a hole in a compression rib. This took a little bit of eyeballing, but it worked out OK.  
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Paul drills the hole through the compression rib.  
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And again on the other side...  
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Perfect!  
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The other side shows how neat the holes come out.  
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As you can see, the jig makes for very accurate alignment without wallowed-out, ugly holes.  
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The installation is tidy on the inside as well.  
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The bigger your washers, the better. We use a 4130 steel plate over the whole face of the block to spread out the loads as much as possible.  
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All these wires took less than a single afternoon to install, not counting the time it took to build the alignment jig and the flat hardware (mostly just tabs and crush plates.)  

Sun N 'Fun 2004 April 2004
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Article by Mike Whaley
 
April was dominated by Sun N Fun in Lakeland. The Model 14 was there, and recieved a great deal of attention. Curtis spent time with us, as did Caro Bayley and other aerobatic notables. Check out the SNF 2004 Event Report for the full story (and lot of photos).


Summer 2004 Status Update May 2004
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Article by Mike Whaley
 
We are now moving into the "details" stage of development. The "big stuff" is mostly done - the basic structure of the wings and fuselage and hanging the engine on the mount. Now we are focusing on the myriad of detailed parts - instrument panels, linkages, adjustable seats, etc. These are obviously just as important to the project, but they often aren't as eye-catching as the big assemblies. These details need to be developed with great care, since they are items that the pilot will use often... if they aren't right, then they will become ongoing annoyances. Being a prototype aircraft, this is the proper time and place to develop these systems. We refuse to offer any product that's not up to the highest standards of quality, even if that means it will take longer to develop. In the end, every hour of development we spend now will save each future builder many more hours, dollars, and headaches later, so it's wise to invest as much time now as necessary.

Continue on to the following entries to see the progress!


Aluminum Turtledeck June 2004
(Week 1)

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Article by Mike Whaley
 
In the first part of June, we evaluated several options for the turtledeck and ultimately decided on an all aluminum structure which is held together with a combination of rivets and epoxy adhesives. Despite the size of the assembly (it's a very tall turtledeck compared to many biplanes) it is actually quite lightweight, very strong, and offers a respectable amount of room for storage (of course, the amount that you can store in it will also depend on weight and balance considerations.)

We had to work out a few difficult curves near the fin, and even covered the section around the base of the fin and the rear edge of the turtledeck with fabric a few times to work out both what shape to make the turtledeck and how the fuselage-fin-turtledeck junction would look. It turned out that we just added a simple, sanded wooden filler strip on each side of the base rib of the vertical stabilizer to provide a smooth transition for the fabric between the fuselage, turtledeck, and fin.


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We initially put some fabric on to get an idea of the shape that we would need to make the turtledeck.  
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As you can see, there are still some serious cosmetic issues to sort out at this point!  
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The test pieces don't need to be pretty, just functional.  
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The turtledeck assembly is all aluminum. It's fairly large, but lightweight.  
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There's a good amount of room for sleeping bags, first aid kit, overnight bag, etc.  
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The rear of the turtledeck assembly. The wooden filler strips are visible at the top of the photo.  
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This is the simple solution to getting the fabric to make a nice curve on the tail.  
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Another view of the filler strips.  

Sheet Metal Work, AirVenture June 2004
(Week 4)

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Article by Mike Whaley
 
The last part of June got busy as we got to the point that we had to get the airframe cleaned up and ready to roll to Oshkosh.

Barrett added some additional reinforcements to the inside of the side panels, using special adhesives to bond the aluminum braces to the inside of the aluminum side panels without marring the outside surface with rivets. We also tweaked the fit of the top panels so that they would clear the cabane attach points.

We also fitted the three separate panels to the instrument panel. It's starting to feel more like a real live airplane now! (Should we decide to alter the layout of the instruments later, this will be quite simple... our in-house waterjet cutter can quickly cut a perfect panel based on a CAD drawing.) We will offer these panels to builders, either with or without instrument and mounting holes cut out (we've actually been offering this service for a long time.)

In July, we loaded the plane onto a trailer, covered it with plastic wrap, and hooked it up to Paul's RV for the long ride up to Oshkosh. It was quite a sight to see! It made it there and back with no problem... the procession did attract quite a bit of attention wherever it went.


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Barrett Brummett roughens the surface to ensure a good bond between the side panel and the reinforcement stringers.  
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The cockpit area has a neat appearance, even without the internal fairings installed.  
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Inside of the cockpit area.  
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The instrument panel area.  
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The instrument panel area.  
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There are three separate panels.  
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Instrument panel.  
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The cabane attach point.  
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The cabane attach bracket on the underside of the center wing section.  
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Loaded up and ready to roll!  
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The Model 14 shouldn't be too difficult to transport on the ground if need be.  
 

Adjustable Seats, Part 1 August 2004
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Article by Mike Whaley
 
We often get inquiries from potential builders along the lines of "Hi, I'm 6 foot 8... can I fit in a Skybolt?" or occasionally we also get "I'm really short, do I need to modify the plane in any way?" As we looked at the seat setup, we made the decision that there was really no good reason that both these folks shouldn't be able to fly the same Model 14 easily, and without having to pull out the welding rig in between. It's a shame, but most aerobatic homebuilts (and quite likely, most homebuilts in general) don't provide for much, if any, seat adjustments beyond changing the amount and thickness of the seat cushions.

Of course, any adjustable seat system must be sturdy enough for aerobatics, and work well enough to justify the added weight and building time. And it should be easy enough to use that the owner won't curse his or her decision to install it in the first place.

What we came up with is one of the most configurable systems we've seen, and it's really not terribly difficult to build once the geometry is laid out. (Yes, we did go through several iterations until we got it just right.) All adjustments are independent, which allows for a great many combinations of positions.

The rear seat can be adjusted fore and aft at both the top and bottom of the seat back, and the seat bottom can be adjusted up and down on both the front and rear edges. This allows the pilot to have total control over the fore-aft position of the seat, the height of the seat pan, and the angles of the seat's bottom and back.

There is slightly less adjustability to the front seat, which is permanently hinged to the fuselage at the top of the seat back (necessary since immediately behind that lies the instrument panel, and there isn't room for the telescoping fore-aft adjustment strut as in the rear seat). The bottom of the strut connecting to the front of the seat pan is also fixed to a fuselage cross-piece. However, the height of the front and rear of the seat pan, as well as the fore-aft position of the bottom of the seat back is adjustable.

Adjustments are made by a simple system using locking pip pins going through holes to lock in the location for the various seat adjustments. This is strong, sturdy, and very unlikely to loosen on its own even under serious vibration and G loads, yet the seat is very easy to adjust in a multitude of ways to accommodate most pilots. The seat frames and mounts are all made of 4130 chromoly.

We feel that this system will be very adaptable and is well within the average builder's capability to get right during construction.


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The original seat layout wasn't bad, but it is always a guess as to just where to put the seats to best fit everyone that will fly in the plane. There must be a better way!  
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The old seats had to come out, so that we could develop a better system.  
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We used steel rods to help align the short sections of 4130 tubing which will serve as the locations the seat bottoms can be locked into.  
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The rails for the seats.  
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The rear seat offers plenty of adjustments!  
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Barrett tries out the new arrangement.  
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This shot gives an idea of how tall the airplane really is.  
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Mike Hughes tries it out.  

Adjustable Seats, Part 2 December 2004
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Article by Mike Whaley
 
Here are some more details about the adjustable seats.


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Front seat.  
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The rear seat adjusts in several directions.  
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The rear seat.  
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The front base of the front seat is fixed, but the top side of this strut is adjustable providing for a large range of motion.  
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This is the top of the front seat back. The locking pins are easily available and sturdy, and won't release until you depress the button on the top.  
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The top of the rear seat back can be moved forward so that shorter pilots can get closer to the rudder and instruments.  
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This shot shows the top of the rear seat frame, as viewed from the rear of the aircraft.  
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Access to this area should be extremely easy through the hinged side panels.  
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Hinges are simple and are made of 4130 tube.  
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For extra safety, each pin will be attached to the nearby structure with a lanyard to prevent it from getting dropped or lost.  
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There is many inches worth of adjustment available. You could extend the concept even further if you wanted to and provide for finer adjustments or an even larger range of motion, but that's probably unnecessary.  
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The angle of the front seat pan is determined by a combination of the height of the front support, and the fore-aft position of the whole seat.  
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While not terribly complicated, this is the most complex part of the rear seat assembly.  
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The rear seat's back panel will only extend down to the cross-piece. This will allow the seat pan to be raised up if needed.  
   

Wings December 2004
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Article by Mike Whaley
 
The wings are progressing. During the hurricane period when there was a very limited amount of work that could be done, we did what we could... John made some durable female molds of the wingtips. We will be offering lightweight and durable fiberglass wingtips (all wingtips will be identical and interchangeable.)

Other areas that we've worked on are improving the mechanical aspects of fabricating the parts. For example, we can often combine two or more smaller individual parts into an equivalent single part that can be easily cut out on the router. We have also been able to refine certain part's shapes to allow for a little more clearance so that another part can be put into place more easily. All the drawings are done in CAD, which we then use to cut most of the parts out on our CNC machining equipment. Therefore, improvements can be made very rapidly and if the nature of the revision warrants it, we can generate a revised part quickly to use on the prototype.

As you view these photos (taken in late 2004) please bear in mind that this is just a snapshot of a work in progress. The wing structure will be refined further before the plane actually flies, and parts of what you see here will be, or have already been, changed to improve the aircraft or building process in some way.