Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by jthunt, Mar 17, 2012.
Just started installation of retractable landing gear on aircraft. Nose gear are installed and also hydraulic power unit.
All controls of landing gear hydraulic system will be installed in the nose cone, for easy excess and close location to pilot cabin.
Main L\G will be powered from there too.
Today we're installed "emergency gear down" hand pump
=very clever thing!
Looks good. If the hydraulic system isn't intact (e.g. blown seal somewhere, etc), is there a way to unlock the mains and shake them down, or a wire to pull them overcenter and into the downlock, etc?
No way for main gears, they will not lock, same way it's will be on Cessna's or Lancair IV aircraft. This is problem with main landing gear go into back of fuselage and they will not go to overcenter against airflow, if no hydraulic fluid left for "hand pump".
Since its a ducted fan and doesnt have a prop to strike against the ground, he could technically just get away with some skid pads.
Some aluminum "knee pads" right where the aircraft makes contact with the ground when its gear up. Just riveted or epoxied on.
This way the fuselage wouldn't be making direct contact and the pads would take the scraping instead of the expensive composite fuselage.
=big problem with dust in air inlets...
=NO upper inlets!
Some aircraft used a compressed gas cylinder teed into the hydraulic line with a valve. You could remote mount the bottle, freeing up some space near your feet and it works even if there is no fluid left. Maybe something to consider for production models.
I meant for emergency belly landings only.
The T-37 had a setup like that, something like 3000 psi in a small "blowdown bottle." One shot.
=1.1 l, 0.6 kg , 300 bar.
Seems like a good weight for this. I would think 1.1 liters at 4500 psi should be enough, unless there's a massive leak. I suppose a check valve would be needed to assure the air goes only to the gear cylinders, not to the hydraulic pump. This approach might be lighter and more likely to work than the hand pump if the fluid leaks out, but would require more work and possible damaged parts to test it. High adventure!
-I try to replace alu 0.6 l bottle (1.3 kg) to the composites one (0.5 kg) in my
SECOND CHANTZ recovery system, for KASPERWING...
1.1 l ,0.7 l...STAKO ,Poland
Main landing gear on this aircraft, still be somewhat intruded in air stream, we didn't want to cut main structure of airframe. To do this, we did restrict travel of landing gear legs in retracted position, by installation of extra support(it's can be seen on photo). This is only for prototype aircraft, next aircraft mains will be fully enclosed.
Front gear is fully retractable into nose cone and have wheel well doors.
We're know, that this prototype aircraft will lose some performance in cruise speeds, but doing this, we will save time and money to certify this aircraft with new landing gear.
Very nice. Unrelated: I've always appreciated aircraft designed to minimize damage in the event of a gear-up landing. The A-10 and some other airplanes leave the retracted wheels down a little below the main airframe, covered by gear doors with a small blister. In the event of a gear-up landing, with a little luck the gear doors scrub through and the tire touches the ground before anything else and begins rolling, and the only significant damage is to the gear doors (and the pilot's pride--and insurance rates). "Those who have and those who will . . ."
Yes, its extremely important to protect the fuselage from belly landings, even if its just some aluminum skid plates glued to the most vulnerable part of the belly.
A few pounds of sacrificial aluminum or steel could save a lot of expensive work if there is ever a belly landing.
Installation of retracts almost done.
-this year ? (winter time soon...)
No problem with that, "large engine(LS6)" - a lat of heat! Cabin heater working wonderful - in the winter we can fly in T - shorts!
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