Quantcast

Search results

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

  1. Heliano

    Brake effectiveness standards

    To further feed this debate: two relevant parameters: torque and energy absorption capabilities (absoption: brake assembly absorbing the aircraft's kinetic energy). As for energy, the thing becomes critical when it comes to aircraft that have high takeoff/landing speeds. I see two main problems...
  2. Heliano

    Redrives for most commercial engines.

    pictsidhe, here goes something I've learned from a czech guy after many years spelling "lomcevak" myself: The correct word is "lomcovak". After all the czechs are the ones who invented this maneuver...
  3. Heliano

    When or how can a certified aircraft engine become "Experimental"? Also, once that happens, can the owner rebuild it themselves?

    A quick remark about what Rockiedog2 said: Yes, it sounds strange asking for AD compliance when the whole aircraft is experimental. However there may be a reason: here in my country the flight permit for initial flight testing of an experimental aircraft is different for a non-certified engine...
  4. Heliano

    Redrives for most commercial engines.

    A quick comment on the very interesting point brought up by wsimpso1: It seems to me that 23.371 addresses the engine mount system. The cyroscopic loads on the engine and its reduction gearbox (if any) are - correct me if I am wrong - in Part 33, more specifically Subpart D (Block Tests)...
  5. Heliano

    Pusher verses tractor propeller

    One quick remark about Vigilant's comment: I have the same question to the FAA, because twin-engine aircraft that do not have acceptable performance to fly one-engine-out can be more dangerous than single engine aircraft: trying to fly a poor performance twin engine aircraft with a failed engine...
  6. Heliano

    Not so complicated but proven conversion?

    I do not know Jan but I've met Mark Kettering (the guy behind Aeromomentum) during the 2018 Sun and Fun. We had a long chat. Then I attended to one of his lectures. I came back home impressed not only with his engineering background, but also with his attitude: demonstrating frankness, openess...
  7. Heliano

    Not so complicated but proven conversion?

    I know a gentleman who makes the Hyundai conversion with a belt reduction drive (with hydraulic belt tensioner) and charges R$29000. That translates roughly to US$4850. The youtube link is below. Sorry: the video is in portuguese, and to make matters worse the spoken portuguese has a heavy Rio...
  8. Heliano

    Brake effectiveness standards

    Here go some numbers: friction coefficient of light aircraft tires: 1 - dry paved asphalt or concrete: 0.4 to 0.5 2 - wet paved (brilliant, mirror-like surface, but no water layer): 0.1 to 0.3 3 - loose gravel: 0.25-0.30 If the brakes can generate enough torque to bring the tire to the...
  9. Heliano

    Not so complicated but proven conversion?

    Here in my country a new conversion is becoming popular - a Hyundai three-cilinder, turbo. The advantage? there are two: 1 - Very light engine. The whole installation including PSRU weighs 80Kgf (176lb) 2 - The turbo ensures higher power at high altitude. A non-turbo engine loses about 25% of...
  10. Heliano

    Not so complicated but proven conversion?

    Aeromomentum has good engineering behind it. And one more hint: fuel injected engines are substantially more efficient than engines with carburetors, let alone two-stroke engines. A typical carburetor-equipped Lycoming does .47lb/h/HP at best; a fuel-injected Aeromomentum (Viking 130 and Rotax...
  11. Heliano

    motor mount offset for "P" factor

    Two things: 1 - Shifting the engine to the left: does not address the problem 100%: there are two propeller effects: one is due to angle of attack, which causes the right side of the propeller disk to produce more thrust than the left side; the other is the twisting effect the propeller has on...
  12. Heliano

    Green zinc chromate primer as final finish

    Zinc Chromate is banned here. We use strontium chromate or two-component epoxy primer instead. The epoxy primer works well with for aluminum/galvanized surfaces but can also be used on steel.
  13. Heliano

    Presurization - Whats it take ?

    I am reading the postings and learning a few things in the process. Yes, composites are structurally complicated because they are anisotropic, non-homogenous and exibit non-linear elastic behavior. And it depends a lot on how the laminations are done. Even the use of finite element analysis is...
  14. Heliano

    Presurization - Whats it take ?

    Matt, As you have experience in analyzing airframes, you certainly know that static strength analysis methods produce more reliable results than fatigue analysis. That is why when a fatigue analysis is done, a scatter factor - typically somewhere between three and four - is used. The reason is...
  15. Heliano

    Using only GPS as your EFIS inputs??? Why u do dat?

    LIttle comment here: all gyros which are not electromechanical are rate gyros. Laser ring gyros (such as the IRS's in Boeing aircraft) or fiber optic gyros (as in some regional and business jets) are rate gyros. And so are those $5 tiny solid-state IMU's you find on the Internet. To make a rate...
  16. Heliano

    Presurization - Whats it take ?

    Designing a pressurized fuselage is feasible. However my suggestion is: if the designer has little or no experience evaluating fatigue and crack propagation (fault tolerant pressure vessel), move away from aluminum. Aluminum is light, it can easily be bent, folded, stretched and riveted but it...
  17. Heliano

    Vortelator?

    As far as bureaucracy and red tape, there is just one thing to do: cry on each other's shoulder. Want a proof that a good part of the bureaucracy is useless? compare the fatal accident rates between fully Part 23-certified, light single engine aircraft and L.S.A. aircraft. It is surprising...
  18. Heliano

    Vortelator?

    May be there are diferences between FAA and Brazil's ANAC. The written regulations are essentially the same, but the way the inspectors see them is different. Perhaps our Feds have a more bureaucratic, less common-sense approach here: "if the mod has a measurable effect on operational...
  19. Heliano

    Vortelator?

    Interesting comments, especially those made by Victor Bravo. It all boils down to how much energy is transferred to the airflow. It is preferable to have a thin layer of turbulent flow attached to the surface than a large volume of turbulent flow, even if the large volume separation happens...
  20. Heliano

    Prandtl lift distribution for conventional configurations?

    I want to add a few comments to this very interesting thread: 1 - If the idea is an aircraft with fuselage, be careful with spanwise lift distribution methods, be it Prandtl's lifting line, Schrenk, CFD or whatever: the fuselage has an important effect: a drop in lift in the center portion...
Top