Project Definition

Introduction


Lighter, more efficient engines and continuous fastening are the keys to a cycle of lowering weight can lead to small airplanes with reduced construction time, lower cost, drastically lowered fuel costs,  similar or improved performance, and greater strength and structural integrity. 

Caveat: These changes are not meant to back fit to existing airplanes: the changes in weight centers and inertias is too great, especially with respect to a much lighter engine - at the very least a design would have to rebalance the whole.  

However,  since laminar flow is at about LCG, reskinning the first 60% of the wings might not be unreasonable, especially for a would be glider or motor-glider, except that the dynamic balances would change.  A change in engine alone (if the engine were adequate) might only require extending the nose.

Caveat two: if all of the components of an aircraft are lightened with no changes in strength except increases, the overall structural strength is increased.  However, in the details, there will be disadvantageous changes as well: "You've got to give up something on penetration, fatigue, welding[effects], corrosion, fire resistance [and] anything too good to be true" - personal communication, Dr, Ming Ma, 10/16/15.

In one line: the project would build two identical aluminum airplane wing sections (with length of about 3-4 ribs) , one section  with conventional means, one with innovative means, then test and compare for strength and other flight relevant properties.

The project could be completed in 3 to 6 months.  If it were to be a visible "working panorama" it would be desireable to be in a windowed or directly public accessible space.

Ideally, the project would lead to later constructing an airplane based on this initial effort, and flown by those who make a contribution to the project now and in the future.  Since the building of an aluminum kit or sub-kit, at any given moment, can be as animated as the proverbial grass, the project, could be supplemented with a motion-triggered time-lapse video (made by smartphone) of any active work on a monitor screen controllable by anyone present - or on this website. 

Additionally, a computer simulator could be available where visitors could fly that same model example of what we are building towards (suitably constrained to be operable in an enjoyable manner by those unfamiliar with flight simulators,  and a website (part of the one you're browsing now) bringing it all together

[hobbling the simulator so that an adult could operate it: key redefinitions, fewer key definitions, greatly expanded use of artificial stability on all axes, and all flights controlled by Flight Management System based on canned various canned Flight Plans the visitor can select.  The visitor would then turn the autopilot off to gain control and turn it back on to save himself.  Children and especially capable adults would have access to a Cookie to open up all detailed controls and ditch the artificial stability]->move to appropriate section.

The Innovation could have a motto: "The $10 hamburger" or "One Gallon per Hour"; that is, 1 [to 4] gallons/hour auto fuel (about $3 [->$10]) versus about 6->15 gallons/hour aviation gasoline (about $25->$75 per hour). That’s a motto. The underlying idea is to reduce the operational cost (by a huge margin), the build cost, boredom and time (homebuilt or manufactured) and increase the performance and structural strength and integrity of small aluminum airplanes -- for airplanes within reach of the average (flight enthused) citizen, to make realistic flights, and with innovations that can be applied to other airplanes.  We will approach this goal primarily with improvements in weight and aerodynamics (both keying off the limiting of riveting, for starters), using light aircraft engines burning as little as 2.5gph of auto fuel, (averaged over normal flight regimes, in an aerodynamically fairly clean LSA.) [get the reference to the LSA club study that made these measurements].   Secondarily one might employ feathered descents (engine off, propeller set to a low drag position), a cockpit tablet App suggesting changes of altitude, heading and speed for Optimal Fuel Routing (or optimal ETA, or even Optimal Thermal routing).

The "Cycle" of lowering weight refers to such as the following: lighter engine with lower fuel consumption -> less fuel required -> smaller/fewer tanks -> less hp required -> lighter engine -> and so on.

Another part of lowering the weight is moving to alternatives suitable for aircraft use but not yet in common use.  For example a Lithium-Iron battery for an IO-540 weighs 4 lbs (!) against the current 30lbs.  Skin plate chosen without need to inhibit rivet induced distortions.  Skin plate chosen for local forces, e.g thinner on the way out the wing - often ignored by kitplane designers. 

To attract attention to "Ten Times Less on Fuel" or "$3/hour for fuel" for a public with no special aviation knowledge, one might make provocative comparisons to the most popular hybrid automobiles.  The aviation savvy hopefully would respond to such as $5/hour versus $25/hour (or $10/hour versus $75/hour for planes with larger engines).

A contender for an eventual project airplane is variation on the 2-place Xenos motor-glider kit.  With an engine (such as that mentioned) that is selectable in flight (currently via throttle position choosing its multiple injection/ignition maps) for miserly consumption and permitting only LSA speeds, or alternatively high performance; this would be an exciting airplane: a Glider (24:1 (stated) glide ratio, significantly better with our modifications; and just fits a T-hangar), or without its wing extension tips (which it wouldn't need if it had truly laminar flow): LSA or (with just one aboard) its an Acrobat, or performance Sport Plane.  It can be flown by an LSA Pilot (or above of course), or a Glider Pilot.  Or an RV-10,  Super Decathlon (alum. tubing, alum sheathed wings) as LSA.  If registered as a motor-glider not only can it be flown a la LSA with drivers license instead of air medical, it is subject to NONE of the LSA restrictions except weight.  It can be flown by Glider Pilot at any altitude,  speed (<VNE),  at night, IFR,... 

 

Work to get started toward this Innovation Goal. 

0. Set up the simulator.  Set up the workspace.  Set up a motion sensitive stop motion camera.  Build any jigs that will be needed.  Build any ribs that will be needed.  Build a 200F deg. oven for curing VHB big enough for a 2-rib wide section.  Start build end plates for each section and their join, and roof rack for aero testing.

1.    Build two Sonex (or Sonerai) (has same laminar airfoil as Xenos and parts and manual are more accessible)  aluminum wing sections (citation now no longer relevant https://sites.google.com/a/schwenn.com/caprice/vtailfastened conventionally on one section,  and with "continuous"  alternatives to rivets (75+ lbs. on the 750lb Xenos) on the other.  For example, 3M VHB tape (wherever possible),  brazing,  and possibly “welding films” such as "aerospace" AF30 wherever peel strength [discuss peel strength considerations in detail]  would be paramount or where a (perfect) weld would be better than a screw or bolt.  VHB is thin layer of viscoelastic acrylic dense foam with an acrylic adhesive on each side. Taped panels can be removed if necessary, without any damage. Different families of VHB accommodate different purposes and materials. (Following the signature below are links to VHB and to its detailed properties.)  A single plate would be used between each rib pair, running from >= 60% of chord on upper surface around the leading edge and aft to >= 30% of chord on the lower surface.  An alternative to welding film for peel strength would be, per skin plate, two rivets at the aft edge of both upper and lower corners.

2.    Perform the strength, environmental, and other tests necessary to see if it is safe and practical for flight (and how it compares to riveting).  (Many of the tape, film and glue properties, and others are published and supported.)  VHB tape is often used to fasten the multi-ton windows, decorative facades, and mirrors above our heads in new buildings, many airliners' flaps' stainless steel scuff strips (since 1984), instead of rivets in the bulk of the U.S. Ambulance fleet, and is still weathering Missouri's hot/cold/humid environment and the Netherland's rain and salt air, with highway signs fastened to their supports 25 years ago.  On an aircraft, this would be faster and easier to assemble; lighter than rivets; permitting much more laminar flow (a substantial reduction in drag) due to fair panels, no air leaks, and damped vibration; reduce difficulties due to fastening mistakes; eliminate fastener corrosion; and seal against dirt, dust, ice, water, salt water, and other liquids.

(Simplified) testing for laminar flow [see the note on significant problems with laminar airfoils in the Illustrative Example above] , its extent and conditions under which it fails and with what result, and the comparative L/D for the two spans would be done on an automobile with the two spans rigidly attached spanwise and mounted on two load cells (giving  on each end a vertical and a longitudinal force).  The whole would be mounted on a roof rack with a forward extension sufficient to clear flow disturbed by the vehicle.  Angle of attack would be adjustable.  There are somewhat crude means available for visualizing the extent of laminar flow that may have developed.  Zig Zag turbulator tape could be used "after" finding location of transition-to-turbulent lines.

Regenerate interest in General Aviation via:

  • A. Large reductions in operational costs.
  • B. Large reductions in construction time
  • C. Equal or improved performance.
  • D. Increase interest/motivation during construction
  • E. Show an easy path to hybrid, and later electric
  • F. Demonstrate other possibilities opened up by our innovation: It floats!, pressurization, fastening unlike materials, full laminar via wing aspiration, natural points for skiis, gliding, enormous range, ... 

Contributions/Loans/ - needed and (already available)

  1. Big LED screen (on loan)
  2. "Big Tools":
  3. Power Tools:
  4. Hand Tools:

    Text Box

    • Torque wrench
    • Solid Riveter
    • Symmetric metal snips
    • Metric Socket set
    • Common hammer
    • Cable cutter
  5. Minimal (<< $100) Android phone, to do motion-detected time-lapse video.  (The Apps are more are less free; the phone can probably also play the assembled video by bluetooth on the big monitor).

Budget

  • A  Sonex ribs and spar caps ~$600
  • B VHB tape
  • C  Welding Film
  • D 4 Load cells for aero testing
  • E

This is how our organisation will gain.

  • A
  • B
  • C
  • D
  • E
  • F If testing is successful we would have a natural lead-in to a grander full plane project.

Objectives

Lower price, lower costs, high performance aluminum airplanes.

Measurable Objectives:

  1. This working website ready to use. 
  2. Public portion of website (this website) ready. 
  3. Member vote on terms
  4. Space arranged
  5. Tools and other materials acquired
  6. Kit and presentation ready.
  7. Fins (and supporting structure) constructed
  8. Supplementary construction for laminar flow tests finished
  9. Tests begun

Deliverables

  • Test results and interpretation
  • Discussion of general changes required once a design is greatly lightened to re-establish proper stability and control.
  • Photo of (agile) participants standing on the unsupported fins
  • Plans for further work (e.g. complete airplane)

Project Constraints

  1. Resources available: $, tools, gadgets,... 
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