Massive yet tiny
Joined: Feb 2007
Posts: 4,598
Likes: 0
From: Amsterdam
Lots of rambling and personal frustration going on. The fundamental design may be sound though, but the devil is in the details... Cooling, lubrication, ...
His comparison to the jet engine is wrong, I believe. A propellor-driven aircraft will not be able to reach a speed higher than approximately mach 0.6 due to mach tip effect. Unless a radical new propellor were to be designed that is efficient and quiet at supersonic speeds. A jet engine is good for at least mach 0.8. So the power-to-weight ratio is not the only reason for switching from propellors to jet engines. But he makes it look like this could potentially replace all the jet engines of the world.
His comparison to the jet engine is wrong, I believe. A propellor-driven aircraft will not be able to reach a speed higher than approximately mach 0.6 due to mach tip effect. Unless a radical new propellor were to be designed that is efficient and quiet at supersonic speeds. A jet engine is good for at least mach 0.8. So the power-to-weight ratio is not the only reason for switching from propellors to jet engines. But he makes it look like this could potentially replace all the jet engines of the world.
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
Posts: 15,113
Likes: 1,087
From: Wandering the FIR and cyberspace often at highly unsociable times
Yes, to develop that sort of power there is a huge amount of heat to be dissipated. It looks like conventional materials have been used with very low surface area. It's been tried before and failed as far as reliability was concerned.
I hope it works though.
I hope it works though.
Joined: Jun 2009
Posts: 97
Likes: 0
From: Hong Kong
The concept was presented years ago and the inventor won the first prize for the design concept at the 2005 Emhart-NASA Tech Brief.
To me the personality issues are not important here (although in this case it has been a obstacle for the further development). More important is the fact that some people are thinking out of the box and sooner or later something that suits the context will be adopted. Those kind of projects (there are several) deserve much more input if we ever want to move on. Many ideas were thought to be impossible by many, not least the airplane.
To me the personality issues are not important here (although in this case it has been a obstacle for the further development). More important is the fact that some people are thinking out of the box and sooner or later something that suits the context will be adopted. Those kind of projects (there are several) deserve much more input if we ever want to move on. Many ideas were thought to be impossible by many, not least the airplane.
Last edited by XLC; 22nd October 2011 at 08:55.
Joined: Dec 2005
Posts: 437
Likes: 0
From: LKBU
Originally Posted by BackPacker
A propellor-driven aircraft will not be able to reach a speed higher than approximately mach 0.6 due to mach tip effect.
Joined: Feb 2007
Posts: 4,598
Likes: 0
From: Amsterdam
Tell it to the creators of Tu-95
Joined: Dec 2005
Posts: 437
Likes: 0
From: LKBU
I have also heard that it was loud as hell due to the tips going supersonic.
By the way, there was a civil version as well, called Tu-114, used in 1958-1976 on long-haul international and domestic flights - not only by Aeroflot, but also by Japan Airlines. So, it was loud but not so loud as to preclude civil operation.
Joined: Nov 2008
Posts: 118
Likes: 0
From: Suffolk
Wikipedia calls these swing piston or chasing piston engines, there is a quotation that "the swing-piston design combines all the disadvantages of the rotary with all the disadvantages of the reciprocating". Swing-piston engine - Wikipedia, the free encyclopedia
This HYT engine design is targeted at providing an alternative to large sophisticated muti-cylinder diesel engines. According to a quick search on the web there is also a history of groups working with this type of rotary design for small car engines. The e-mobile hybrid uses a rotary chasing pistons design that, as far as I can make out from the graphics, is a spark ignition that fires once a cycle. In the graphics of potential applications for the e-mobiles engine it includes light aircraft.
This HYT engine design is targeted at providing an alternative to large sophisticated muti-cylinder diesel engines. According to a quick search on the web there is also a history of groups working with this type of rotary design for small car engines. The e-mobile hybrid uses a rotary chasing pistons design that, as far as I can make out from the graphics, is a spark ignition that fires once a cycle. In the graphics of potential applications for the e-mobiles engine it includes light aircraft.
Thread Starter
Joined: Jul 2009
Posts: 519
Likes: 0
From: London
Well with regards propeller efficiency, is the unit not small enough to drive a fan instead of the jet in a high-bypass turbo-fan engine? That might go some way to assist cooling as well. I've no idea about what the effects of high altitude might be on it, so there's a potential pitfull for commercial use.
That's a great video Stephen on how rotary vane engines actually work!
Another potential power plant could be the Energy Catalyzer which (supposedly) works by a Low-Energy Nuclear Reaction, although since it produces steam-power lugging around tons of water probably makes it inpractical for aviation.
That's a great video Stephen on how rotary vane engines actually work!
Another potential power plant could be the Energy Catalyzer which (supposedly) works by a Low-Energy Nuclear Reaction, although since it produces steam-power lugging around tons of water probably makes it inpractical for aviation.
Joined: Jun 2003
Posts: 13,787
Likes: 0
From: EuroGA.org
Very interesting 
Thanks for the post. (Next time pls use a descriptive subject ).
I guess the Wankel-type tip sealing may be an issue, but Mazda more or less solved that, AFAIK. But they solved it on a watercooled engine; aircooled ones need looser tolerances.
Thanks for the post. (Next time pls use a descriptive subject
).I guess the Wankel-type tip sealing may be an issue, but Mazda more or less solved that, AFAIK. But they solved it on a watercooled engine; aircooled ones need looser tolerances.
