Help needed - landing gear spring calculations
02-26-2008, 10:24 AM
#1
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Help needed - landing gear spring calculations
Guys, I'm re-fitting a 20Kg plus MB339 for a client and the springs fitted to the landing gear are not even supporting the fuselage in its empty state, I believe the gear was a one off fabrication, as was the kit originally so maybe the springs fitted were just temporary and never got properly sorted out - I do not believe the jet has ever flown, just photographed static.
Is there a calculation that can be made to establish what sort of loading a spring or springs (x3) need to sustain to support a
20Kg plus jet model during takeoff, landing and taxiing?
I'm hoping someone can help out[
]
marc.
Is there a calculation that can be made to establish what sort of loading a spring or springs (x3) need to sustain to support a
20Kg plus jet model during takeoff, landing and taxiing?
I'm hoping someone can help out[
]marc.
02-26-2008, 10:52 AM
#2
RE: Help needed - landing gear spring calculations
Hydraulic is the best way to solve your problem,look here.
http://www.skymasterjet.com/339.htm
http://www.skymasterjet.com/339.htm
02-26-2008, 11:38 AM
#3
RE: Help needed - landing gear spring calculations
ORIGINAL: marc s
Guys, I'm re-fitting a 20Kg plus MB339 for a client and the springs fitted to the landing gear are not even supporting the fuselage in its empty state, I believe the gear was a one off fabrication, as was the kit originally so maybe the springs fitted were just temporary and never got properly sorted out - I do not believe the jet has ever flown, just photographed static.
Is there a calculation that can be made to establish what sort of loading a spring or springs (x3) need to sustain to support a
20Kg plus jet model during takeoff, landing and taxiing?
I'm hoping someone can help out[]
marc.
Guys, I'm re-fitting a 20Kg plus MB339 for a client and the springs fitted to the landing gear are not even supporting the fuselage in its empty state, I believe the gear was a one off fabrication, as was the kit originally so maybe the springs fitted were just temporary and never got properly sorted out - I do not believe the jet has ever flown, just photographed static.
Is there a calculation that can be made to establish what sort of loading a spring or springs (x3) need to sustain to support a
20Kg plus jet model during takeoff, landing and taxiing?
I'm hoping someone can help out[
]marc.
we had some similair problem here also.
can you share the diameter en length you have now?
i also need the thickness of the wire
also count the layers
02-26-2008, 12:36 PM
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RE: Help needed - landing gear spring calculations
OK here we go.
Free length of spring 110.77mm
Coil width 17.5mm
Wire thickness 1.65mm (1/16th)
No of coils shown in pics attached.
marc.
Free length of spring 110.77mm
Coil width 17.5mm
Wire thickness 1.65mm (1/16th)
No of coils shown in pics attached.
marc.
02-26-2008, 12:48 PM
#7
RE: Help needed - landing gear spring calculations
ORIGINAL: marc s
OK here we go.
Free length of spring 110.77mm
Coil width 17.5mm
Wire thickness 1.65mm (1/16th)
No of coils shown in pics attached.
marc.
OK here we go.
Free length of spring 110.77mm
Coil width 17.5mm
Wire thickness 1.65mm (1/16th)
No of coils shown in pics attached.
marc.
that wont carry even a wooden airframe..
the minimum should be 2.5mm thickness and a bit longer
you guys have like a factory who make springs?
here you give them the data or the spring , give them the weight needed .
they will sort out a spring for you.
i havent got that model , mine would be to weak also
funny thing is that the details fo your spring alsmost are the same for our rookie front oleo.
also enclose a short piece of thin teflon tubing on the end so when you hit the tarmac hard , it will dampen the drop a little.
02-26-2008, 12:54 PM
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RE: Help needed - landing gear spring calculations
It seemed very light duty!
Question is what are the expected weights (forces) subjected to the spring in landing, is say 4-5 times the model weight reasonable? If this is the case would I need a spring capable of supporting say 80-100Kg at maximum compression or is my gestimate way off?
marc.
Question is what are the expected weights (forces) subjected to the spring in landing, is say 4-5 times the model weight reasonable? If this is the case would I need a spring capable of supporting say 80-100Kg at maximum compression or is my gestimate way off?
marc.
