Posts: 119 From: Lorain, Ohio, USA Registered: Aug 2008
posted 06-25-2015 01:54 PM
Yesterday I acquired a pair of U-2 Pogo Sticks. These are the wheeled struts (?) that support the fueled wings prior to takeoff. They basically fall off after the aircraft leaves the ground to conserve weight.
In an effort to provide good information in my classroom, if anyone has direct knowledge or information about these things, please share! Was a "release pin" involved? Friction fit? What happened if wing for some reason bounced?
What I do know is that these things are larger than I thought and heavy!
My final question is concerning restoration. I think they would present much better back in original condition. Is this a bad idea? Diminished value or history?
I'm considering restoring one and leaving one.
SpaceAholic Member
Posts: 4437 From: Sierra Vista, Arizona Registered: Nov 1999
posted 06-25-2015 02:09 PM
This video may prove helpful; appears the pogo is pilot released.
DG27 Member
Posts: 173 From: USA Registered: Nov 2010
posted 06-25-2015 11:46 PM
According the the U-2 flight manual, the pogos fit up into a socket and simply fall out when the aircraft lifts off. There is no pilot control for the pogos or cockpit indicator. The pilot can see the pogos from the cockpit. The pogos can be secured in place for ground handling by a safety pin.
In the video previously posted, you can see the red remove before flight streamers of the pogo securing pins hanging down along side the pogos, during taxing. Then when it is sitting prepared for takeoff and the ground ops people drive around the U-2 doing one last check, you can see the safety pins are removed.
The first fatality in the U-2 occurred on 15 May 1956 when during takeoff the pogos failed to release. The test pilot Wilbur Rose was able to shake loose the left hand pogo. In an attempt to shake loose right hand pogo, the aircraft stalled and crashed sadly killing the pilot.
You have a great piece of history from a remarkable aircraft.
DG27 Member
Posts: 173 From: USA Registered: Nov 2010
posted 06-25-2015 11:54 PM
To answer your original questions, the pogos fit into the wing with a loose socket fit, not friction, as they are designed to fall out. If a wing bounces while taxing the pogo will fall out which is very undesirable. This is why they use a securing pin for ground handling and pull the pins before flight.
David C Member
Posts: 1014 From: Lausanne Registered: Apr 2012
posted 06-25-2015 11:55 PM
quote:Originally posted by Constellation One: What happened if wing for some reason bounced?
I think a bounce on take-off is very unlikely. It would imply an incorrect performance calculation, rough runway, mishandling or unanticipated weather. Great attention is paid to all of those. Landing would be interesting, no doubt one reason (apart from shear impracticality) that they aren't used.
gliderpilotuk Member
Posts: 3398 From: London, UK Registered: Feb 2002
posted 06-26-2015 07:16 AM
The pogos prevent a wing dropping on take-off before sufficient lift develops. The U-2 effectively lands as a glider (wingspan is only 3ms greater than the largest span glider), with similarly configured undercarriage. In theory, keeping the wings level until speed tails off should be the same - although the extra span and large empennage increase the instability in crosswinds. Pogos on landing wouldn't necessarily help with this.
Constellation One Member
Posts: 119 From: Lorain, Ohio, USA Registered: Aug 2008
posted 06-26-2015 12:44 PM
Thank you for the great information and the video link.
They will make for good references.
Now I just need to find a good way to display these guys.
mikepf Member
Posts: 441 From: San Jose, California, USA Registered: Mar 2002
posted 06-26-2015 03:02 PM
Display should be easy. You just need to get the rest of the U-2.
posted 06-25-2015 01:54 PM
advertisement