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  1. karoliina.t.salminen

    A complete report on the aerodynamic and strength design of an ul aircraft

    The fuel consumption is very optimistic. What engine did you design the plane for? What is the cruise L/D and the L/D max?
  2. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    To continue, with electrics, the differential for cruise power and VTOL power can be high. Launch could be 700 hp and yet the cruise would be under 100, preferably no more than 50 hp. With electric motors this is not difficult, but normal, very much like Tesla which is cruised at low power, but...
  3. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    This is reply to 5 min to launch, it takes less than minute to launch VTOL. 5 mins would involve hovering that the VTOL must not do, for safety and energy consumption reasons. In fact only 30 seconds could be enough to launch above the trees for transition to horisontal flight.
  4. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    Old model S cells are 190 Wh/kg, the Gigafactory cells are better, and the new 200 kWh roadster would indicate that even much better. Because the model S is a heavy car and with its batteries the 200 kWh roadster would be almost three ton car, but it isn't. Something better is in the Gigafactory...
  5. karoliina.t.salminen

    Chinese Electric Airplane

    Turnigy was not first electric. It was Yuneec. Turnigy is brand of Hobbyking RC shop. And some have used the biggest Turnigy motors in electric ultralights like Electric Lazair (before he switched to higher quality Joby motors after apparent KV problems with turnigy, KV not low enough).
  6. karoliina.t.salminen

    Generators for hybrid systems

    And if you think of the portable generators out there, here is where you would go wrong. There is no practical way to use these in airplane because the power to weight ratio is too poor and the power output is too poor. Only way to successfully do a hybrid is to use a brushless motor as...
  7. karoliina.t.salminen

    Generators for hybrid systems

    I think best working example you can see is the Pipistrel's hypstair project. I think it has Siemens electric motor both as generator and drive motor (two motors because it is series hybrid). The motor is mounted directly to the Rotax drive shaft with the reduction gear removed. The generator's...
  8. karoliina.t.salminen

    Fly by wire and control laws for EAB FBW

    Every Chinese RC hobby shop has ”stabilizer” units for RC planes, intended especially for FPV pilots. One does not need to understand the math on integral level as finished algorithms exist and are adaptable for free (open source), waiting for just takers. Then there is an alternative...
  9. karoliina.t.salminen

    Stall Speed / CLmax /magic

    Certified aircraft, at least the newer ones, tend to have IAS and TAS very accurately agreeing with the ground speed (G1000 on Diamond, or Avidyne or Garmin on Cirrus). Published numbers in handbook also agree with actual ones quite accurately. The manual of Cirrus even has tables for speeds for...
  10. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    One idea for the 400 km electric plane. It could have part of battery pack replaceable with generator engine. In short distance flights it would be full electric, and on long distance trip needed, the battery module is taken out and engine is installed in its place. It would not necessarily need...
  11. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    Also interesting comparison of expenses: 100 hour pilot time on AVGAS GA almost equals the OEM price of the battery pack. At the price of fuel, you could buy new batteries. How kewl is that?
  12. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    The non-VTOL would be practical if there was fast chargers installed on every air field. Current state is that not even standard plug is available, so room for improvement on this enabler is plenty. But if fast chargers existed, it would be fine for student flights. In here there is some...
  13. karoliina.t.salminen

    Why battery-powered aircraft will never have significant range

    Cirrus SR22 type airframe is not good example, because you would not really go anywhere with Cirrus at 80 kts since even best L/D speed is much higher than 80 kts on Cirrus. I understand your comparison is not necessarily to exactly Cirrus, but maybe aicraft with cockpit as roomy as Cirrus has...
  14. karoliina.t.salminen

    Lilium - Point to point small air transport reinvigorated?

    I have considered the doors. The wing geometry and spar locations make this approach very restrictive. Unless the plane is a flying wing where there is more space for the props and doors.
  15. karoliina.t.salminen

    Lilium - Point to point small air transport reinvigorated?

    Casey Neistat's drone flight was not ducted fan, and normal props, not fans, lifted the youtuber just fine, but nobody sane designs a vtol around small ducted fans with high disc loading. Tesla battery pack is enough for 700 hp power output, in aircraft much less is required for vtol takeoff...
  16. karoliina.t.salminen

    Weight estimations based on modern composite airframes?

    Basically for the electric plane, it would make sense to exclude weight of everything except airframe. Landing gear, control surfaces, canopy and and flaps belong to the airframe, so these shold not be excluded, but engine and all of its systems should be excluded to estimate how much there...
  17. karoliina.t.salminen

    Weight estimations based on modern composite airframes?

    Yes. I know the MCR01, I have flown one. But the reason is simple. The MCR is a mini-plane with full carbon structure whereas the DA20 has carbon only in spar. The Diamond has also (according to my mechanic) not so good fairings (from weight perspective): they have wing eg joint filled with lot...
  18. karoliina.t.salminen

    Weight estimations based on modern composite airframes?

    Typical weight estimation data is pretty old today, like the one in Raymer's book. I think it would be useful to have statistics of modern aircraft airframe weight statistics split by at least major component, or in minimum the total empty weight of the airframe minus engine and minus propeller...
  19. karoliina.t.salminen

    Lars Giertz's VMaxProbe (N1200M)

    My RC plane Skywalker X8 flips over on landing if stalled with full stall, due to reynolds number effect. The NLF 414f + low reynolds number is not very good combination. I think the Vmax probe would have been safe with low reynolds number airfoils and a little larger cabin to fit the helmet...
  20. karoliina.t.salminen

    Rutan Ski-gull

    My guess is that VGs are not quite compatible for flying in known icing. Neither is laminar flow airfoil. Same goes the other way around, deicing boots will kill any potential laminar flow and make the boundary layer fully turbulent. Bleeding wing does not fare that much better in average...
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