REFLECTOR: G Load testing my Engine mount

[michalk]

Did you design it yourself?  Do you have CAD drawings?  If not, maybe 
try the local college that teaches CAD.  Or, if it's not too complex, 
send me the drawings.

Get someone to do a finite element analysis on it.  Shouldn't be too 
difficult.  That will tell you the design load, and that should be way 
more than what it will see in service.  You have G's, and a design load. 
  Whichever is lower, do that test, and check for deformation.

Metal fatigues with cycling, not necessarily loading.  If your airplane 
is a 6G airplane, I would test the engine mount 6.6 or seven G's.

If your FEA comes back and says that you can only put 3 G's worth of 
load, then you now have a 3G airplane.

Scott Derrick wrote:
> I will be testing my engine mount for G Load testing this week.
> 
> What should I test for?    Aerobatic load is 6 G's, but thats a 
> temporary load.
> 
> Is their a difference between a continuous load or an intermittent 
> load?   When an airframe is tested for 6 G's, is that a 6 G continuous 
> load?
> 
> The problem is I don't think I can put a short duration 6 G load on it.
> My setup is to bolt the mount to my front loader.  Hang a palate from a 
> wood frame resting in the mount where the engine bolts on. Then start 
> piling sand bags on the palate hanging below the mount.  I don't think 
> my back hoe can lift over a 1500 lbs with the front loader so I will 
> have to set it up in position empty or say with 1000 lbs on it, and then 
> put more and more weight on the palate as it is hanging.  Stopping when 
> I get to the required weight which for 6 G's is about 2700 lbs. Then 
> remove the weight and measure the mount to see if there was any 
> permanent deformation.
> 
> Scott
> 
> 
> 
> 
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