At 08:22 AM 12/7/96 GMT, you wrote:
>My inclination (so far theoretical, if not heretical) is to bypass all this
>rubber block stuff and go straight for a nice conventional adjustable coil
>spring/damper arrangement. If you look at current racing motorcycle/car
>technology, they use short stroke alloy dampers, adjustable for both
>compression and rebound damping, as well as spring preload. There are
>certainly units about that would seem to fit the bill: I believe all F1 cars
>use Penske shocks, often (if not universally) with titanium springs.
>(Somewhat expensive, but ever so light)
>
>Anyone have any idea what the effective spring rate is on the Europa
>suspension system?
>
>Miles
>
>
>Shock Absorber
Here's the problem (all figures approximate):-
1 Europa = 1300 lb
x 2g landing = 2600 lb (our nominal design case for the shock absorber
system - NOT the undercarriage mounting frame strength).
Mechanical advantage of swinging arm = 4
So load on shock absorber = 4 x 2600 = 10400 lb
Stroke available = 1.25" (So to answer another question the shock absorber
rate required is about 3.75 tons / inch).
Height available = 5.25" (though this could be increased slightly if you
follow the principle of our present damper system mounting method)
Cost - no more than the present method.
All "tried and tested" solutions gratefully received.
With regard to the level of 'g' experienced by the aircraft - on the drop
tests the reserve energy case (where the structure is allowed to be damaged
but must not fail) required a drop velocity of 10.17 ft/sec. The "aircraft"
rig was brought to rest in 10.75", which is an average deceleration of about
1.8g. The 10.75" was accounted for partly by the tyre deflection and partly
by the shock absorber deflection.
Regards
Andy
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Web Site at www.europa-aviation.co.uk
Fax No 44 1751 431706
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