• Welcome aboard HomebuiltAirplanes.com, your destination for connecting with a thriving community of more than 10,000 active members, all passionate about home-built aviation. Dive into our comprehensive repository of knowledge, exchange technical insights, arrange get-togethers, and trade aircrafts/parts with like-minded enthusiasts. Unearth a wide-ranging collection of general and kit plane aviation subjects, enriched with engaging imagery, in-depth technical manuals, and rare archives.

    For a nominal fee of $99.99/year or $12.99/month, you can immerse yourself in this dynamic community and unparalleled treasure-trove of aviation knowledge.

    Embark on your journey now!

    Click Here to Become a Premium Member and Experience Homebuilt Airplanes to the Fullest!

Search results

Advertise with us
Find deals on ebay
Find deals on amazon
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
  1. Y

    Austro Engine successfully tested brandnew rotary engine AE80R

    I came across an interesting feature of Austro engines : the rotor is forced-air cooled, not charge cooled. That is, the centrifugal impeller you can see on the engine is used to force cooling air through the rotor; thus the charge is heated up by cooling down the rotor and thermodynamic...
  2. Y

    ducted fan expertise on this forum

    Hello I have had the opportunity to work this summer on a shrouded propeller for paramotor. That's obviously a bit different than a ducted fan, mostly because I was using the shroud to increase static thrust. All I can say is, I have had hell of a hard time running CFD simulations of the...
  3. Y

    New LSA engine - "work in progress"

    I dit not ;) I'm perfectly aware a supercharging is needed. That still makes it very interesting. What I would like to see in this particular configuration is actually a freewheel turbocharger, which would be geared for low speeds and then spin freely at higher speeds. Cyril
  4. Y

    New LSA engine - "work in progress"

    ****. Just when I was considering an opposed piston design for a prototype in years to come. I'm very happy to see than someone came to this design once again, concerning aviation particularly. Still I would like to know for which reason you chose a valve design, obviously 4 stroke. A 2 stroke...
  5. Y

    Ducted fan aircraft

    Yes a propeller will probably have a better efficiency without a duct which represents a lot of drag. But concerning the shroud, it DOES make a difference. Provided a shroud is always considered to be airfoil-shaped to provide its own thrust. Obvisouly it only works for speeds at which the duct...
  6. Y

    Ducted fan aircraft

    That's because there is confusion here between duct and shroud. A duct is basically a tube helping reducing propeller tip loss. The gain exists but is marginal. But a duct is generally to be considered as length equal to diameter. When shorter, it's called a shroud. Shrouds should work in a...
  7. Y

    Ducted fan aircraft

    And that's clearly not as good as a 1.8m propeller. Plus you can get additional thrust by working the shroud to act as an airfoil, but I don't think this is what has been done here. I don't really get the aim to go for electric and meanwhile ruin the propulsive efficiency. I considered going for...
  8. Y

    $5,500 aircraft?

    Why are you trying to reinvent ultralight engines whilst plenty is available ? Solo 210, Polini Thor, Vitorazzi Moster, Hirth F33, Ros 100 / 125, Top 80, H&E R120, Corsair M21, M19, M25, Simonini Mini, ... They are available from $2000 and allow you to drive a 1.3m propeller which means much...
  9. Y

    Ducted fan aircraft

    Given the diameter of these fans, the efficiency is likely to be pretty close to 0 ...
  10. Y

    Cool Pou but I can't read French

    If you need some information I could translate ;)
  11. Y

    Mr. Meridith's Mysterious Effect

    I would be carefull with the ramjet comparison. As far as I'm concerned, my domain is limited to subsonic, incompressible (M<0.3) airflow. Thus, the cooling duct should be a divergent to compress air, not a convergent as a ramjet. I might be stating the obvious but I felt the need for it. I...
  12. Y

    13B cad drawings?

    Guys, rush to grabcad.com ! They have some very useful CAD models, particularly aircraft engines, and several Mazda wankels, included a 13B IIRC.
  13. Y

    Resin Infusion - thin laminate

    Agreed, I tend to think that solid foam core is the best option for control surfaces, provided the core is a low density foam and the skin is thick enough to provide additional stiffness. Be carefull with local articulations on such a lightweight structure. They will either weaken your structure...
  14. Y

    What would you change on the ch-701?

    Now owning a Bingo (predecessor to the Savannah), there are some important details I would change about the 701. The first one is a terrible mistake from the designer in my opinion : not using the wing airfoil on the fuselage roof. There is a great loss of lift in there and since it is...
  15. Y

    composite wing construction

    Parabeam looks interesting, makes me think a lot of a Nidacore product. Contacted them for some information, never got any answer. Though I think Parabeam is perfectible regarding fiber orientation. The way they are laid up doesn't seem quite strong. I prefer the Nidacore-style 45° orientation...
  16. Y

    composite wing construction

    Autoreply, I must say you're quite right about the rib shape. For an obscure reason, I wanted at first to completely get rid of ribs, but for some time now I have been considering coming back to a more classical structure. Anyway that doesn't change the way I would build the wing, just...
  17. Y

    composite wing construction

    Increasing the number of ribs also increases weight, for sure, but it seems to me that it is a mistake to try to eliminate either ribs or skin core. They are best used together. Ribs are great to transfer the loads between the pressure side and the lift side, skin core is great to prevent the...
  18. Y

    composite wing construction

    Bill, I agree than core thickness is extemely efficient regarding skin stiffness, but as it covers twice the wing area, the weight can escalade very quickly. For a 10 sqm wing, a 5mm thick of 80kg/m3 foam already weighs 8kg. I feel it more efficient weightwise to minimize the skin thickness and...
  19. Y

    composite wing construction

    I have recently come to an ideal composite wing building process. It consits in a cored ski (very thin core to limit weight but significantly increase skin stiffness), and featuring foam ribs. The idea is to have a LE and a TE assembly. Start with the LE : use a hotwire-cut PS mold, so as to lay...
  20. Y

    New carbon fibre material

    I have contacted them a couple of months ago. 40e ($50) per sqm. That is ridiculous. I can't see no reason to use spread tow over multiaxial fabric other than aesthetic concerns. If aesthetics justifies to triple the price.
Back
Top