Life is like a doughnut...

No_one21

Obligatory: MMMM Doughnuts!

But yea just wanted to get this out. In the middle of the doughnut of life it just feels hollow. My thesis project has had about a month setback due to my inability to find a phantom leak in our pressure housing. I've tried many many tests and fixes and damn near every exit on the housing is fully epoxied but the vacuum still doesn't hold. Essentially every single day at work I get my hopes up trying some new method only to go home feeling like a failure. At this point I won't graduate this semester and will instead have to graduate at the end of August. My work will likely be done by May but the deadline is in 3 weeks for completed theses. I should feel better than like 20% finish on time but I really wanted to get out and start my career.

Which brings me to the outside of the doughnut! I got my formal offer from NUWC (Naval Undersea Warfare Center) today as mechanical engineer in their Unmanned Underwater Vehicle sector! So, I can't start until I give them my final transcripts, but as long as they don't just retract the offer I officially have a job lined up after grad school. Super pumped.

And the toppings on the doughnut are that an album by a GREAT musician that I know from a forum just got emailed to me as one of the kickstarter donors for it and I'm playing it nonstop. Also, (and I shudder to think of the responses to this) I have a date tomorrow!

Anyways, how are your lives going?

jd50ae

Glad it is all coming together for you, I really am.

Did you try duck/duct tape..?

Puff_Dougie

Congrats, Sam, on the outside and topping of the doughnut!! And I'm sure you'll find the solution to the leak soon! Great feeling, I'm sure, to have a standing employment offer waiting in the wings!

And a DATE to boot!! If she smokes cigars, we will all start living vicariously through you!!

You da man!

New_Boots

time to make the doughnuts

twistedstem

jd50ae:

Glad it is all coming together for you, I really am.

Did you try duck/duct tape..?

Duct tape and Velcro can fix anything!!!

twistedstem

Sorry your project not going as well as expected,just stay positive .awesome news about the job offer!!!sounds like an interesting place to work.and good luck with your date tonight just be yourself and have great time!

No_one21

Thanks guys, there's a possibility I just found the leak! My roommate made an interesting hypothesis and when tested all I heard was like a straw sucking sound so if my fix for this is it then my project moves onward! However, I'm still too far behind deadline I believe so that stuff still sucks.

Also the girl does sometimes smoke and said she'd be happy to have a cigar with me sometime. This date is basically just to see if we want to move forward from what we've been doing lol

Oh and duct tape doesn't work because it doesn't stick to Delrin (my robot's body) and also wouldn't hold a vacuum well, but being an engineer you can't image how many times I tried to use duct tape for the solution

webmost

Underwater drones?

better than sweating it out in your U-boat listening to PING PING PING from the destroyer above

Bigshizza

You're a smart kid, don't spend time wasted on beating yourself up! Start at the beginning and work through the process and you might discover what you are overlooking. I see great things ahead for you! Congrats on the date, save the details for a Vherf in warmer weather.

brianetz1

girlfriends are bad news for the vherf.......just look at Ray. Last night was supposed to vherf, but chose the wife over his BOTL (not that i blame him, i think i would chose her too)

congrats though bud, you'll get through the rest of the crap. Just remember if the worst thing that happens to you in your life is that you graduate in May instead of march you have lived a charmed life.

allsmokedup

For detecting vacuumoost leaks:
1. light up a cigar
2. blow smoke into the ingress
3. connect up whatever you use to pressurize the housing.
4. look for smoke escaping
5. profit!

Glock1975

brianetz1:

girlfriends are bad news for the vherf.......just look at Ray. Last night was supposed to vherf, but chose the wife over his BOTL (not that i blame him, i think i would chose her too)

congrats though bud, you'll get through the rest of the crap. Just remember if the worst thing that happens to you in your life is that you graduate in May instead of march you have lived a charmed life.

Lol, I bet u would big boy.

No_one21

allsmokedup:

For detecting vacuumoost leaks:
1. light up a cigar
2. blow smoke into the ingress
3. connect up whatever you use to pressurize the housing.
4. look for smoke escaping
5. profit!

I actually saw that in my research on what to do, but I can't smoke a cigar in my lab lol Seems like that would be a rough thing to justify in my budget. "It says you spent $1000 on cigars?" and then me, "Well I only needed one, but things got a little out of hand... ooops"

However, I have technically found and fixed the leak! I just need to make the fix more permanent and able to withstand any fatigue and then I can get back to testing. I was so happy yesterday I was jumping up and down. I've also realized that missing my thesis deadline is a good thing now because the Navy is fine waiting a few more months and that means my stress level gets basically halved with a later deadline.

Thanks again guys for the kind words!

New_Boots

Now that I'm not on mobile

Jetmech_63

allsmokedup:

For detecting vacuumoost leaks:
1. light up a cigar
2. blow smoke into the ingress
3. connect up whatever you use to pressurize the housing.
4. look for smoke escaping
5. profit!

+1, the old school way of detecting ECS leaks on F/A-18's is to fire up a motor, light 5 or so smoke bombs in a coffee can and set the coffee can under the intake:) Kinda frowned upon these days though.

Hang in there Sam! Dont go all ROUGE and get DOUBLE down on yourself, Life may be a doughnut but damnit, its a CHOCOLATE donut! So cheer up, be STOUT about things and watchout for INCOMING!

No_one21

Jetmech_63:

allsmokedup:

For detecting vacuumoost leaks:
1. light up a cigar
2. blow smoke into the ingress
3. connect up whatever you use to pressurize the housing.
4. look for smoke escaping
5. profit!

+1, the old school way of detecting ECS leaks on F/A-18's is to fire up a motor, light 5 or so smoke bombs in a coffee can and set the coffee can under the intake:) Kinda frowned upon these days though.

Hang in there Sam! Dont go all ROUGE and get DOUBLE down on yourself, Life may be a doughnut but damnit, its a CHOCOLATE donut! So cheer up, be STOUT about things and watchout for INCOMING!

No_one21

Just thought I'd update this a bit. The below is a video of the first successful test of my thesis project. It's not too exciting in general but here's a quick explanation. What's in the water at the bottom of the shiny aluminum structure is essentially a robotic turtle fin. It is being towed in the water while flapping to simulate the forward motion it would produce if it were attached to the underwater vehicle it came from. There are pressure sensors I've installed in the fin mechanism to tell me the 3D forces acting on the fin as it flaps. So, the point of the thesis is to test the fin at different distances from the bottom to see if the force sensors can detect a fluid flow phenomena called "ground effect" and just see if we can detect other interesting fluid flow aspects as they affect the fin.


Original Video - More videos at TinyPic

Hopefully you can see that it's like a turtle fin near the end there.

Stubble

No_one21:

successful test

Congrats!!

Jetmech_63

Thats friggin interesting! What kind of control are you using? As in, i see the fin is moving and that the angle of the fin(coming from an "angle of attack" standpoint) is variable but are you comparing it against fixed angle, fixed speed and fixed rate of decent towards the bottom of the pool to get somewhat of a baseline ground effect pressure spike?

No_one21

Jetmech_63:

Thats friggin interesting! What kind of control are you using? As in, i see the fin is moving and that the angle of the fin(coming from an "angle of attack" standpoint) is variable but are you comparing it against fixed angle, fixed speed and fixed rate of decent towards the bottom of the pool to get somewhat of a baseline ground effect pressure spike?

Not 100% sure on what you're asking but I'll try to answer the best I can. This is a 2 degree of freedom fin which has a roll motion and pitch motion controlled by separate motors. Roll does not change the angle of attack, pitch does. While it is rolling and pitching in a sinusoidal motion, it is also translating through the water at about 0.5m/s by being towed.

As far as ground effect is concerned, the fixed wing fixed angle of attack is very well documented because that's what airplanes and helicopters deal with. However, varying the angle of attack as well as the height over ground in a flapping motion has very little data. Most is done with high frequency/low amplitude and my fin is low frequency/high amplitude. So we aren't comparing it to other tests really, we're comparing the forces found in open water (not near the ground) and then forces found getting closer to the ground. The differences in lift and drag due to proximity to the ground will be the "ground effect" basically.

y2pascoe

No_one21:

Obligatory: MMMM Doughnuts!

But yea just wanted to get this out. In the middle of the doughnut of life it just feels hollow. My thesis project has had about a month setback due to my inability to find a phantom leak in our pressure housing. I've tried many many tests and fixes and damn near every exit on the housing is fully epoxied but the vacuum still doesn't hold. Essentially every single day at work I get my hopes up trying some new method only to go home feeling like a failure. At this point I won't graduate this semester and will instead have to graduate at the end of August. My work will likely be done by May but the deadline is in 3 weeks for completed theses. I should feel better than like 20% finish on time but I really wanted to get out and start my career.

Which brings me to the outside of the doughnut! I got my formal offer from NUWC (Naval Undersea Warfare Center) today as mechanical engineer in their Unmanned Underwater Vehicle sector! So, I can't start until I give them my final transcripts, but as long as they don't just retract the offer I officially have a job lined up after grad school. Super pumped.

And the toppings on the doughnut are that an album by a GREAT musician that I know from a forum just got emailed to me as one of the kickstarter donors for it and I'm playing it nonstop. Also, (and I shudder to think of the responses to this) I have a date tomorrow!

Anyways, how are your lives going?

Congrats on the job at NUWC! I work over at the Navy hospital across the base. I also like donuts.

No_one21

y2pascoe:

Congrats on the job at NUWC! I work over at the Navy hospital across the base. I also like donuts.

Wow small world. You gotta tell me all about the B&Ms on that side of the bridge!

y2pascoe

No_one21:

y2pascoe:

Congrats on the job at NUWC! I work over at the Navy hospital across the base. I also like donuts.

Wow small world. You gotta tell me all about the B&Ms on that side of the bridge!

Tobacco Road in Newport is the one I like to hang at when I can. It's on the corner of Training Station & Smith Rd., at the light before Gate 1. His stock is a little to be desired at the moment but he's got a great smoking lounge and a very distinguished set of regulars.

The other is the Humidor Cigar World on upper Thames St. Great selection but no lounge to speak of.

No_one21

y2pascoe:

No_one21:

y2pascoe:

Congrats on the job at NUWC! I work over at the Navy hospital across the base. I also like donuts.

Wow small world. You gotta tell me all about the B&Ms on that side of the bridge!

Tobacco Road in Newport is the one I like to hang at when I can. It's on the corner of Training Station & Smith Rd., at the light before Gate 1. His stock is a little to be desired at the moment but he's got a great smoking lounge and a very distinguished set of regulars.

The other is the Humidor Cigar World on upper Thames St. Great selection but no lounge to speak of.

Cool. I was looking at Tabacco Road since it will likely be closest to where I move to. Only thing I was worried about is if their stock is low then I'd like to bring my own, but then you pay the $10 cutting fee so I'd rather pay that for cigars. If I transfer my friday B&M routine over there, I'm sure Tabacco Road is where I'll end up being somewhat regular.

Jetmech_63

My bad, I was coming at ground effect from the aviation side of the house. The test birds we have have pressure sensors all over them and they use it occasionally to test diffrent weapon load outs then land it at diffrent speeds to validate the ground effect envelope the computers generate. Speed vs AOA vs lift vs weight. But our wings are fixed so mad props to you for doing this while adding motion .

No_one21

Jetmech_63:

My bad, I was coming at ground effect from the aviation side of the house. The test birds we have have pressure sensors all over them and they use it occasionally to test diffrent weapon load outs then land it at diffrent speeds to validate the ground effect envelope the computers generate. Speed vs AOA vs lift vs weight. But our wings are fixed so mad props to you for doing this while adding motion .

Haha I forgot jetmech knew planes. Wow can't believe I was kinda explaining ground effect to you but yes the extra rotations add a lot of complexity which I'm currently drowning in.