[OT] Bugatti, a Beauty in Every Shape and Make!

[kolibri282]

One of the coolest looking aircraft ever:


Enjoy!

https://www.facebook.com/TheBugatti100pProject/videos/vb.261574317253048/843683509042123/?type=2&theater

http://www.gizmag.com/bugatti-100p-aircraft-prototype-replica/38440/

 

[Smack]

It looks like they've repaired it after the nose-over last year on the first flight and have done the gear retraction tests.
I would love to see more of this beautiful project and can't wait to see it fly with the gear up.
Outstanding.
Brian

 

[All_In]

It does look SWEET!!

 

[Doug Riley]

Counter-rotating props. Now THAT's a way to get rid of torque roll.

 

[Jean Claude]

Yes, Doug. It also is a way to avoid the rotational losses, great to hight speed.

 

[C. Beaty]

These guys weren’t too concerned about torque roll; their main goal was the reduction of rotational loss.

 

[dinoa]

They say you can hear the "Bear" before it's picked up on radar.

 

[kolibri282]

And the "Bear" is the fastest prop aircraft in the world.
http://sunrise.freeforums.net/thread/47/tu-95-fastest-propeller-aircraft

One small problem remaining: you'd need one hell of a pilot to bring her around the pylons in Reno....;-)

Bonus pic:
https://northatlanticblog.files.wordpress.com/2015/06/tu-95.jpg
Note vortex in the background:
http://wallpaperbeta.com/wallpaper_2560x1440/tu-95_bear_missile_carrier_aircraft_2560x1440_hd-wallpaper-249269.jpg
CA-95?
http://media.englishrussia.com/022013/rusbearintheair/rusbearintheair001-14.jpg

 

[C. Beaty]

The only application where counterrotation seems to be universal is powered parachutes where it’s important, I suppose, to eliminate both gyroscopic and translational effects.

There used to be a story about a practical joker that fitted a large gyro wheel in a piece of luggage and used it to spook baggage handlers at airports. Obviously would have been in the days before X-ray inspedtion of baggage.

 

[phantom]

I have built gyros with counter rotating props and I found that if each engine could pull 250 pounds on a scale with the other one shut down the total thrust with both engines running was less than 500 so the coaxial prop is less efficient for some reason. Overlapping side by side or synchronized intermeshing is almost as efficient as two props clear of each other with flow straightening vanes.
Norm.

 

[kolibri282]

coaxial prop is less efficient for some reason

I take it you used the same props front and rear? The prop pitch has to be slightly larger on the rear due to the increased velocity that one sees. Contra-rotating props are an area where proper design is the key factor, but then... is there any field in engineering where proper design is not of utmost importance? From this wiki article:

Contra-rotating propellers have been found to be between 6% and 16% more efficient than normal propellers

https://en.wikipedia.org/wiki/Contra-rotating_propellers

Some further reading:
http://naca.central.cranfield.ac.uk/reports/arc/rm/1995.pdf
http://naca.central.cranfield.ac.uk/reports/arc/rm/2084.pdf

 

[C. Beaty]

Two props side-by-side have a total area of 2. If they overlap 100%, then the diameter needs to be increased by the square root of two to maintain the same total area.

Static thrust is highly dependent upon propeller disc loading.

 

[Jean Claude]

I have built gyros with counter rotating props and I found that if each engine could pull 250 pounds on a scale with the other one shut down the total thrust with both engines running was less than 500 so the coaxial prop is less efficient for some reason. Overlapping side by side or synchronized intermeshing is almost as efficient as two props clear of each other with flow straightening vanes.

Norm, At high flight speed the loss due to axial momentum becomes small, and the rotational loss becomes great. So, increase the flow section of propellers is less interesting than recover rotational losses.
At low forward speed (gyroplane), it is the opposite.

 

[Arnie Madsen]

.
Russian Tupolev TU-95MS ... First half of this video is great .... shows the c/r props in flight

Last half kinda boring ... shutdown and restart and props in slow motion etc.

.
www.youtube.com/watch?v=q-2dfEc70gU