• 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

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
  1. Andy_RR

    Pulling versus pushing - which way is better?

    If you run the numbers on prop wash speed for a given cruise thrust, you'll find that it's not more than a poofteenth faster than the free airspeed. When you're climbing at higher thrusts and slower speeds it's more, but not so much more. If you run a large diameter propeller (hard for a...
  2. Andy_RR

    10/23 Raptor Video

    This thread has reached new heights of distressing on so many levels.
  3. Andy_RR

    10/23 Raptor Video

    To be fair, I doubt anyone here would have predicted this failure mode prior to its actual occurrance. While I agree the design is something that even Heath Robinson would reject out of hand, it demonstrates how difficult developing a reliable reduction drive can be. Doing it in the air is a...
  4. Andy_RR

    Mike Patey - Scrappy's Wing

    Pictures or it never happened...
  5. Andy_RR

    Mike Patey - Scrappy's Wing

    Where did he do this? I thought the ali was just a mould surface and the CF was demoulded and used as skins on their own, at least for the fuse.
  6. Andy_RR

    Mike Patey - Scrappy's Wing

    Once you have the CNC capability, which he clearly has, to make those ribs isn't that much of a deal. Not cheap, but not nearly as expensive as you might imagine. The aluminium swarf all goes in the recycling bin so not such a big deal either. It's also worth a bit so will get recycled...
  7. Andy_RR

    Mike Patey - Scrappy's Wing

    I think he's done an amazing thing and is truly with the spirit of experimental aviation. I hope it works well enough to demonstrate during flight test. He's put a lot of design and analysis effort in it, no doubt. The management of the centre of pressure/lift and pitching moment is very cool...
  8. Andy_RR

    Why battery-powered aircraft will never have significant range

    There's a PBS Nova documentary on this electric aeroplane thingy. Worth a watch, albeit it's not aimed at informing engineers. Short version here: The documentary maker talks with Paul Bertorelli here about it all - also an interesting take on it all:
  9. Andy_RR

    Why battery-powered aircraft will never have significant range

    IMO the real problem with multiple propellers if you don't stow some of them is the efficiency at low thrust, i.e. in cruise, is very poor. I guess you could get around this by slowing down and moving to coarse pitch or even feathering unused propellers so you can wind up the efficiency of the...
  10. Andy_RR

    WAM Engines

    Mark Wilksch tells me that despite the relatively poor BSFC of the IDI WAM120 they would routinely plan about 20%-25% less fuel burn on their demonstration Thorpe T211 compared to a typical O-200 example. Despite not being invovled in the current WAM operation - which is sadly a husk of its...
  11. Andy_RR

    Tailless Aircraft - Reflex and other design issues

    Not true. The centre of gravity and centre of lift must coincide longitudinally otherwise pitching will occur. The centre of gravity must be ahead of the neutral point for positive static margin, the neutral point being where the pitching moment curve is flat - i.e. dCm/dalpha = 0
  12. Andy_RR

    10/23 Raptor Video

    Harsh... ...but probably fair.
  13. Andy_RR

    Beta Technologies Alia

    Interesting interview with the founder, Kyle Clark, although the clickbait thumbnail is a bit sad...
  14. Andy_RR

    Where does one find an aerospace Engineer to hire

    To some extent that is the nature of experimental aviation. An engineering consultant with a relatively defined upside will be trying to limit their exposure to downside risk by necessity so out-there experimentation isn't really their thing
  15. Andy_RR

    Minimum drag just prior to flow separation?

    An interesting article here alleges that minimum drag occurs just prior to flow separation - presumably meaning skin-friction drag. https://www.aa.washington.edu/news/article/2021-02-17/new-law-physics-finds-sweet-spot-aircraft-efficiency Paper is here, which I haven't read yet. Something for...
  16. Andy_RR

    Burt's yarns.

    I don't know if many of you have seen this or if it has already been posted here, but this is quite an entertaining series of videos from Burt Rutan. https://www.youtube.com/playlist?list=PLdU9dwAKJIAMDb31yFNyAM8uD0w966thA
  17. Andy_RR

    Whats the best aircraft design software?

    Please don't use X-Plane as a design tool - you'll shoot yourself in the foot. Use MS Excel (or open-source alternatives...) and learn the basics of flight modelling first. That way you'll have less chance of decieving yourself with your amazing ideas. PS: Not at all saying X-Plane isn't...
  18. Andy_RR

    NEW AVIATION ERA...

    The only gains in propulsion efficiency is if you can curb either vorticity or skin friction from existing ideas of lifting surfaces. I think it's possible that oscillating thrusters might do something clever recovering vorticity due to the reciprocating nature - i.e. there is a vortex reversal...
Back
Top