Hover disk lenticular With RC powered trike frame in pendulem effect

 I   want to  do  a stability  test of   a lenticular  envelope  with  my RC  powered  trike frame hanging  beneath the  disk .  The  disk   does not have  enough  gas volume  to  become  LTA even of itself    But it  does  have  the  capability   to  generate a lot   aerodynamic lift because of its  rigid  hoop.  .    Using  lines  connecting to   extended  arm  off  of a   servo , I  want  to  be  able to  change the  AoA   in flight to  witness how   everything  reacts , and  how much  swing is  generated .   If  it  shows  positive  results  .  I plan  to   make  a  different  frame and  use a  rudder in  the prop  wash  for turning   and using  the  AOA adjustment to  fine tune the  AoA    using air speed as  elevator .    
  The  first  step is to   locate  the  trikes weight position   and best hang  distance   from  the  envelope  .  Using  steel  nuts   as  accurate dummy  weight  and  do  a  series  of  glide  tests from  the  roof  by  adjusting the 4 lines  untill I  find  the  happy  spot  for  best  glide ratio.  This  will  be the starting  AoA angle .  The  AoA  will only  reduce from  here  to  find  best  trim  speed.  
  My  experiment  here is  to  determine  if   a  real  life envelope volume  to  lift  50% of the  entire payload  of  the  craft   can  reach  100% lift   from  aerodynamics .   The  envelope  will  be  LTA   and  of course   the  larger  the volume , the  slower the  craft will be    ,  Slower landings  and  slower take off speeds and  slower  forward speeds.  
 This  Model will be   100 %  aerodynamic lift  . Now  I   know  this is  borderline   inflated wing  tech,  and   not  so much  airship , with  this  experiment .  Or  even  if  the  50  / 50 lift  real life version could  be  thought of  as  airship / dirigible  ether ,   But    as a lift gas conserver requiring  much less lift gas  ,  and  requiring   less  materials  to  build  and  smaller size for  storage . ,   plus  using  the  CPS  method  with  hoop  ring  to  rigidities the  envelope aerodynamics like  a  Hover Disk  , Not  needing  a turn table   due to  smaller size using   rudder  steering in  the prop  wash or even   vectoring  thrust  , and  requiring  less  Hp over all  ,   It  could be  a  viable  and  cost effective option for  personal  flight . 

  Now  for  the good  ( or bad part of this)   ,depending  which  side of  the airship  fence you are on   .  Suspose you  designed for  this  sanario . You   developed  a gas leak  and  lost  most of your  gas because a  crazy  bird  attacked your  envelope ,  but landed  safely  And  repaired  the  leak with  gorilla tape . Reinflated  with  air  from  a  friendly farmer   that had  a portable air compressor   and  was able to  fly   again, although now   needing   most of  your   HP  to do it .  Would  that  be  worth it ?  
 Suspose you  could not  afford   lift gas this  month to  top off ,   but  wanted to  fly ,  Would  that  be  worth it ?  Would   having  a wider  weather window  to  fly in  be worth it ?
 So  what  does  the lift gas  do  for  you ?  It  allows  for  much  slower  take off  and landing speeds  by  needing much less  speed   to  generate  the less  aerodynamic  lift required.  The  ability  to  roll  just  a  few  feet into  a  slight  breeze  and be  airborn   ,  Almost VTOL capable  with   Hover  capability  into  the  breeze .  I  think  even  with  a  slight breeze  and No lift gas , only  air ,  and a  Good  AoA  angle,  it  still would have  a  slow  flight  capability comparable to   most  UL's , and the  ability  to  trim out  for  best  forward  speed . 
  So  with  that   I'm going  to  the  roof  and  throwing   my  hoverdisk with  nuts and string  hanging off it into  the breeze .   
           
   
     

 Ok  I have some bad news  to  report .  Flexible  Load  lines  from  the  envelope to  the  Gondola  May  not  be  the  way  to  go.     Ive  tried   many  weight shifts  to positive and negative  COB  tries  and  many  lengths  from  envelope  tries.  from  the very  bottom  of  the  envelope  to  2 foot  away  
  What  s  happening  is    what  is  known in paragliding  as  frontal collapses .  This  is  when   the  weight in pendulum effect  swings   back and  the   leading  edge goes  to  far forward in a negative  AoA and  collapses .  This is particularly  bad  for  the lenticular  because  from  that point of  no  AoA ,  it violently  nose dives  then begins to  flip .  very  bad .  Or  it  violently  snaps  back  up,   Also very bad .  The  lines becoming  slack on  the  forward  or  aft  set  to  cause  this  problem  as  the  weight   shifts   in pendulum  effect  .   I  would also  say  a  sudden  side wind   could collapse lines  from  the  side  and   the  same   thing  happen
 I  see no  way  for  this  to  safely  work    unless  the  envelope uses  struts   to  keep  the  weight  of  the  trike  in  a  fixed  location under  the envelope  and  not lines  or load straps  .  The  farther   away  from  the  bottom of  the envelope   the  trike is,   seems   to  be  an  real leverage  and stability advantage    with  line  or  strut angles  of  30  to  45 degrees   So pendulum effect works  as long as it's  a rigid pendulum  so  the trike  and envelope  move   togather .   As it  stands   now  , its like  having  an  airplane wing  held on  the  the fuselage  with lines .   This needs to  be  a rigid  attachment. 
   Now having  said all that ,  with   lift gas  in  the envelope  this  could change the  outcome quite a bit .  But if   its  designed to  fly  with or  with out  lift gas  as a  safety feature and multifunction  role,   then   the envelope  will need to be  strutted to  the gondola , No  question  about that what so  ever .
   So  now I plan  to  Strut  the hoverdisk  to  the  weight box  and  do  more  glide  tests  . If  it  still wont glide  to  satisfaction ,  then   I  would  call  this  a bust because  this is  the   A #1 safety  feature on most  aircraft .  We can not  be  without  glide  capability.               

Real  weight  calculations  for  AUW .  190 lb  me ,  Trike  and motor gondola  80  lb,   envelope   est  50  lb  =  320 lb  give or take  a few
 Divide by  2   =  160 lb gas envelope lift   =  25  pounds   LTA  when  I   exit  the ship .  So  add ballast  to  have 0 lift when off the  ship . or  make  lift  envelope  slightly smaller  to  say  130   lb   lift  at  2144  Cu ft   and  that is a an Oblate Ellipsoid ( party balloon  CPS  type sphere)  of only    20  ft  dia  X 10 foot  high  
 Thats  dang near  garage size  packable  y'all  !   !     And  Way under 254 lb empty  aircraft  weight  for  FAR 103 !  

The  envelope   would  look  something like  this  half  as tall  as it is  wide

I made a mistake  with  the Oblate Ellipsoid  dome calculator . Its level  was pre set at  9   and  was out of  screen view ,  should have been  at 0 .  I kicked a  few numbers  around  and  got  23  dia   X  8 ft  tall
 almost a  3 to 1  profile  , still  garage or trailer supported hanger  friendly .  I  built the  struts out of  alum  welding rod  and  will  install  them   on  the  disk . Need  to  make  some  hooks  that   attach to the  hoverdisk  fiberglass hoop  ring . and  put  the  cross pieces in  to  support  the  weight box . If it  glides  good enough,   I'll   RC it and  see  what happens  
 Composite  drawing  added pilot enclosure,  Rudder  and elevator in  prop wash .  

The lenticular shape is notoriously unstable.  The US Navy built some experimental saucer shapped planes many years ago and wrote it off as too unstable.  I've played around with lenticular LTA models and found the same thing with the front edge rising and causing it to flip.  The only ways to try and fight this is to sling the payload way down below the hull like it is with a balloon or parachute, or spin the hull to get some gyroscopic stabilization. 
 
Here's a video of a spinning lenticular model I made a few years back:
http://www.youtube.com/user/pyronaught?feature=mhw5#p/a/u/4/iMHIljepNAY

There is no directional control here, only rate of spin and up and down.  The horizontal travel in the video is from very slight air currents.  Having  directional control without using a counter-rotated gondola proved a bit challanging, but not impossible.  I just about had a circuit developed using a micro controller to cycle the engine thrust for creating a net force in one direction, but had to stop working on this due to other work.

The FX5U was canceled because the Navy wanted sexy jets not odd looking  STOL prop planes. 

Of course a "flying saucer" is going to be unstable. If you take the control surfaces off of a conventional aircraft or an airship it becomes unstable too.

Nice test model BTW.

If you have not  seen  the  RC Hoverdisk  fly  yet    Your in  for  a treat . It does  fly   with  good control, and  very good lift .     I'm  looking  for  the  same  lift  But  belly heavy  to be more  stable .  I  think  a  full flying  elevator  may  need to   go  aft  for better pitch control  authority , and  maybe  coupeled  rudders . one in  the  wash   for  0 to 5 mph  forward flight  control as  shown   and  smaller ones   aft   for  control  at  speed.   
   I've  been  wanting to  get  this   disk  to  fly  for  a  while now anyway , I bought  the  RC stuff   and  also built  the  foam leading edge  frame to have a  more solid area  to mount   things  too.  I didnt  like  mounting  straight to the  envelope method as originaly  done ,   Was ( and still can) fly it   in  the   configuration seen  on  RC groups .    But   I'll  experment  with it  for  this application  and  see  what happens .    I also  have   the  8 ft  CPS and polyfastener  envelope I  built  durring  this winters madness , that I want to  laminate  the inside of the  shell halfs   with Kitchen  Aluminum foil , Glue  it  all up gas tight , install  the polyfastener  to ensure the  seam  stays togather  .Also bolt a  hoop  ring  to it ,  This For  testing  helium  perm  and  airfoil rigidness   in conjunction  with  the  CPS  Group Build . So  that  might   provide  a larger  model envelope   for  testing   in  the future.
        http://video.google.com/videoplay?docid=3788107767956938143
 http://www.vimeo.com/clip:187677

Your test were with the hoverdisk right? It has a pretty thin leading edge. The leading edge collapse you describe would be less likely to occur with a fatter leading edge. That fatter leading edge is the way I plan to go.  

 It  wasn't  a  deformation type collapse  Dude ,  The  forward    edge nose dived and   flipped  the  whole  envelope    like   flipping  a coin due  to  the  weight shift   being  free to  rotate  under  by   lines.  . 
 Agreed 100% ! 8)     Bigger , thicker  , and  Full of lift gas , hooped  not hooped,   all  will  make  a big  difference  in  what  happens . At least  with the lift gas  holding  the envelope up ,  Enough so  that  lines or load straps   could  be safely  used. I  feel  confidant in  that .  
  In  this  example of  50 / 50  lift  or  - 0 /100 lift   ,   It  is  a  secondary redundant  function    to  be  able  to  fly  with  no lift  gas , using only  air.  And  as  such   fixating  the  weight to  not  move  in the CoG,  CoL and CoB  will be   mandatory  Thus  , and regrettably ,  Load lines  wont work  here , hard point  mounted struts  will be needed .  
  The  whole idea  behind this and other   threads  , is  to  be  able to  utilize  the  CPS shell   in  a number of   related but different  ways ,  Traditional  Envelope   construction  Is   the   biggest   money  grabber of  all  airship type  projects and  eliminates the  DIY market   right off the bat .  But   the  CPS   should be a affordable  and  home build-able  solution for the  DIY market  that's not been  seen  before !   This  Idea  with  50 / 50  lift   Could make it   even  less expensive  using less , or even  no  lift gas  and   appeal  to   the DIY  segment  .  Exploring possibilities               

I-Man , that was a cool video, thanks for sharing it.  I reminds me very much of the Star Trek Reliant ship from the wrath of Kan movie, this is an encouraging and close model for that ship.   At 160 feet in diameter you could have a lot of people in that size and shape of a ship and get decent speed as well.  It might be commercially plausible.

Would it  not be  the coolest  thing ever  to  have  an  aerobatic  Airship ! Lol ! 
 Yea, I  see what your saying 
   
 How about   Pontoons   for  water  LZ's 

The Reliant, I love that ship, it is my second choice after the Enterprise to emulate into an air ship.  It is a good lifting body, stable, has the landing pontoons/ nacelles and can carry a nice size crew and passengers.   This is a ship capable of making a lot of money, especially as sci fi conventions.  And there is room for a death ray.