Fuel burn and things

[youngmic]

An interesting article on Bio-mechanics in a recent National Geographic appears to be paving the way forward on stall enhancement.

 

Turns out the the protrudences on the leading edge of the Humpback back whales pectoral fins, called Tubercles result in a stall AoA increase of around 8% resulting in a 16% increase in the CL and remarkably a drag reduction of 33%. for the same NACA 0015 section (ie. a whale fluke).

 

Seems this was first discovered in 2003 and is now showing efficiency improvements in wind generator blade design.

 

Just for a bit of interesting info.

 

On pusher engine power on power off stall IAS differences, unless the designer has intentionally limited the elevator effectiveness the difference is attributed to the vertical inclination of the thrust vector, ie. the donks carrying a bit of the weight.

 

 

M

 

 

[motzartmerv]

well, thats a much better way to put it...thanx

 

 

[slartibartfast]

Seems this was first discovered in 2003 and is now showing efficiency improvements in wind generator blade design.

I'm thinking the whales discovered it first.

 

Maybe it was a fluke.

 

 

[motzartmerv]

ohhhh...thats bad starti...

 

 

[bilby54]

Hi Motz, Great to see someone having a go with a string bag (whichever breed) in the Sydney area. The views down that way can only really be appreciated at 60 knots... lol.

 

For what it is worth, I really think that the two stroke engine has had its day and good quality four strokes will become more prevalent due to rising fuel costs and the inefficiency of 2 strokes. You only have to look at trends in motor cycles and outboard engines to realise that this is most likely the way of the future. The Drifter factory offers a Jabiru engine as an option but the real potential is in the motor bike engines.

 

This might even spark a bit of a renaisance in ultralight design until a major engine manufacturer takes up the challlenge similar to Rotax in the earlier days. Imagine a Thruster with "powered by a HOG" painted on the side.... you might have a full time job teaching all the bikey gangs to fly!! Maybe a BMW .... "We have ways of making you fly" or Honda with a whole new meaning to "Goldwing".

 

The European based parts have become ridiculously expensive and TBO for flying school operation, 300 hours, needs to be considered. My Drifter has had a bunch of trouble with the gearbox that is not considered when it comes time to overhaul so get that checked out.

 

Cheers,

 

Bill