Author Topic: Re: .30 cal Condor (Read 20814 times))

QVTom · « **Reply #60 on:** October 22, 2014, 02:46:23 AM »

Your instincts are right on Bob. Yes, the middle section is replaced by the the valve and regulator bosses. The part that I find disturbing is the green and yellow areas along the periphery where the cap and tube meet. 50ksi is near yield of mild steels. I would like to stress that doesn't exceed 20ksi with chromemoly.
I ran another model with a 2" tube, the results are much more reasonable. Max stress is 22ksi in the joint area. Keep in mind that this is 1600 psi and assumes the weld is as strong as the base material.

Definitely needs to be explored further.

Tom

QVTom · « **Reply #61 on:** October 22, 2014, 02:48:45 AM »

Doug, if you want to take a more accurate look send me some drawings so I can model the real deal.

Tom

rsterne · « **Reply #62 on:** October 22, 2014, 12:25:19 PM »

Tom, is the blue colour on the tube because the force is applied towards the end only, not in all directions, in the analysis?.... I would have expected a much higher stress than 2.6 ksi on the tube wall....

Bob

PakProtector · « **Reply #63 on:** October 22, 2014, 12:44:08 PM »

Quote from: rsterne on October 22, 2014, 12:25:19 PM

Tom, is the blue colour on the tube because the force is applied towards the end only, not in all directions, in the analysis?.... I would have expected a much higher stress than 2.6 ksi on the tube wall....

Bob

Tube wall stress will be 10x pressure with a 2.5" tube( r/t being ~equal to 10 in that case )...that just from hoop stress. That's 16ksi in this example not 2.6...the question the sim alarms are indeed ringing.
cheers,
Douglas

QVTom · « **Reply #64 on:** October 22, 2014, 12:48:22 PM »

Yes, we are looking at the end cap only.

rsterne · « **Reply #65 on:** October 22, 2014, 01:20:59 PM »

Thought so.... thanks for the clarification.... It would appear to have nearly equal stress over the outer half of the end plate (ie ignoring the middle where the stress is the highest because it isn't there) that the end plate has to be 2-3 times as thick as the tube, and in addition I would bet that an internal radius where it joins the tube wall is in order....

I hope Doug is following this thread and doesn't continue building his larger chamber.... in fact I'll PM him, hopefully that should email him to alert him....

Bob

dyotat100 · « **Reply #66 on:** October 22, 2014, 03:35:52 PM »

I haven't started on a larger one. One of the earlier ones I built I put it in a bucket of water and filled to 4500 psi. That's all I had at the time. My compressor will do 5000 psi so I could test it that high on Friday.

Here is a rough drawing. I'm at work so this is real close with out measuring it.

dyotat100 · « **Reply #67 on:** October 22, 2014, 04:37:32 PM »

Thanks for all the warnings Bob.

rsterne · « **Reply #68 on:** October 24, 2014, 02:18:55 PM »

Quote

One of the earlier ones I built I put it in a bucket of water and filled to 4500 psi

In case you don't know what power you are playing with.... A 15 CI tank filled to 4500 psi contains ~35,000 FPE of energy.... That's enough to lift a good sized car 10 feet into the air.... I don't think your bucket of water will do much.... Hydrostatic tests are done filling the tank and all lines with water or oil that won't compress and store energy....

Bob

dyotat100 · « **Reply #69 on:** October 24, 2014, 02:35:01 PM »

I know. That was a small reg chamber like on the .30 but shorter.

QVTom · « **Reply #70 on:** October 24, 2014, 03:15:16 PM »

Quote from: dyotat100 on October 22, 2014, 03:35:52 PM

I haven't started on a larger one. One of the earlier ones I built I put it in a bucket of water and filled to 4500 psi. That's all I had at the time. My compressor will do 5000 psi so I could test it that high on Friday.

Here is a rough drawing. I'm at work so this is real close with out measuring it.

Now I understand the design. With the monolithic fitting running down the center the stress on the end caps is considerably less. I'll take a look at this design to see what gives.

Tom

dyotat100 · « **Reply #71 on:** March 31, 2015, 06:41:57 PM »

I forgot to post finish pics. What not worthy is I went and took some barrels and a couple of parts to black oxide yesterday and totally forgot that the reg chamber needed to be done.

Got burned on the anodizing. One piece of the shroud is a gun metal blue. I have come up with a new design and will just replace the last 6".

I make it .100" larger so it doesn't have to match like it does now. I did the .257 and it works pretty good.

KnifeMaker · « **Reply #72 on:** March 31, 2015, 10:36:25 PM »

I see what you mean on the color Doug. Guess it will have to be thrown away. My way that is! LOL!!!

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Re: .30 cal Condor