REFLECTOR: G Load testing my Engine mount

[Scott Derrick]

I designed it myself by merging two separate designs.

I used the Velocity mount for a IO550 for the legs that attach to the 
firewall, and a Cessna 310 mount(TSIO520) for the bed rails that attach 
to the engine.     No drawings, I used pictures and the cut list for the 
Velocity mount and just measured the tubing dims in the 310.

I have a friend with a good CAD program, I will see if it can do the 
analysis.. If not I'll just have to pile the weight on. 

I started to fill sand bags and realized that there will be to many of 
them. I'm going down to the local junk yard and see if they can loan me 
a couple barrels of scrap lead.

thanks,

Scott

michalk wrote:

> 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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