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Old Aug 08, 2012, 10:25 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
Quote:
Originally Posted by alexjschauer View Post
Oh so you're not covering it with typical covering.
You're going to sheet it with balsa and then glass it and paint that?
Sorry for all of the stupid questions...
There are never stupid questions EVER

In the past I have covered planes with everything. I have even sheeted and then monokoted and then painted the monokote.

This plane will be planked, sheeted, glasses, filler, primed, and painted

And feel free to ask anything........

Rock ON!

DAG
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Old Aug 08, 2012, 01:21 PM
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Alex Schauer's Avatar
United States, MN, North Mankato
Joined Feb 2011
4,675 Posts
Quote:
Originally Posted by dag214 View Post
There are never stupid questions EVER

In the past I have covered planes with everything. I have even sheeted and then monokoted and then painted the monokote.

This plane will be planked, sheeted, glasses, filler, primed, and painted

And feel free to ask anything........

Rock ON!

DAG
Thanks!!
Wow that is a lot of work! I bet it will pay off and look super sharp though!!!
Alex
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Old Aug 08, 2012, 04:46 PM
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JIMBOJONES's Avatar
United States, IN, Milan
Joined Feb 2009
459 Posts
Are all the bombs part of the pneumatic system? How do you air everything up, a central fill location?
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Old Aug 08, 2012, 06:21 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
Quote:
Originally Posted by JIMBOJONES View Post
Are all the bombs part of the pneumatic system? How do you air everything up, a central fill location?
There are 11 air tanks, which 6 are made to look like bombs.

I fill everything and regulate the brakes through this station I designed.

Thanks, DAG
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Old Aug 08, 2012, 10:53 PM
Slow 'n Steady...Grease 'r In
kpriddle's Avatar
Maine
Joined Oct 2008
1,264 Posts
Dag,

That's mind boggling! What a station for the air systems only! Where will that be kept?

Thanks,
KP
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Old Aug 09, 2012, 05:01 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
Quote:
Originally Posted by kpriddle View Post
Dag,

That's mind boggling! What a station for the air systems only! Where will that be kept?

Thanks,
KP
Here.....

Thanks, DAG
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Old Aug 09, 2012, 05:11 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
What I got done last night late......

Now we are going to be getting to the hard part. I need to glass half of this so I can cut my door that the strut will push open and is held closed by a bungee. I have it all designed in my head and on paper, but have not mocked it up.

DAG
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Old Aug 09, 2012, 07:20 AM
Its all fun
Tonystott's Avatar
Australia, NSW, Forster
Joined Oct 2004
7,211 Posts
Haven't seen your aircrew lately Dag, I hope that hussie didn't lure them away to leave you working alone! LOL
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Old Aug 09, 2012, 11:32 AM
Flutter-Bys are fun
Conehead's Avatar
United States, MI, Honor
Joined Dec 2005
5,119 Posts
You got some pretty impressive bolt cutters in the background!
It is truely amazing the scope of this project. So many details, so many things to think about, engineer, so many solutions. You mind must go constantly, even when you are asleep to get them all in order.

Conehead
Orrin Eldred
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Old Aug 09, 2012, 04:49 PM
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Propnuts's Avatar
So Calif
Joined Mar 2009
121 Posts
Those aren't bolt cutters. His current draw went a bit over specs and those are his wire cutters for the cabling he had to upgrade to.
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Old Aug 09, 2012, 05:19 PM
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Propnuts's Avatar
So Calif
Joined Mar 2009
121 Posts
Shims under the nacelle formers?

It looks like you had to slip some shims under the nacelle formers - six of the formers coming away from the trailing edge? Is that part of the design, or things just didn't quite fit? I find that hard to imagine given your extensive use of CAD. In my shop - yes - quite probable. Yours? Never!
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Old Aug 09, 2012, 09:30 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
Quote:
Originally Posted by Propnuts View Post
It looks like you had to slip some shims under the nacelle formers - six of the formers coming away from the trailing edge? Is that part of the design, or things just didn't quite fit? I find that hard to imagine given your extensive use of CAD. In my shop - yes - quite probable. Yours? Never!
I was wondering if anyone would see that.

It is a very long story but I will try to keep it short. What happened is I cut a few corners in my CAD design when it came to where the wing would separate. I never did really skin the nacelles in 3D. Once I started installing the nacelles I saw I had made a huge mistake. My wing break was about 1.5" to far inboard which would make the nacelle hang out past the break. I decided to just squeeze in my nacelle sides and make it work. But that looked like crap...... So this really did derail me and made me realize I had to shorten the outboard wing, and lengthen the inboard wing. It was really scary just taking a band saw to a wing you spent 4 months on, but it all worked and I am back on track. Those shims will get some nice little inserts (or not).....

To be honest this took 2-4 months out of me as it really did take the wind out of me to have such a huge mistake..... BUT, now that I am over the hump, and the fact the C119 project is moving at the speed of light I am really itching to get the B-36 done........

I know many people here put me up on a huge pedestal, but I am just a builder who will, and does make huge mistakes in my design......

Rock ON!!!!!!!!!!!!!!!!!!!!
Damon
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Old Aug 10, 2012, 07:05 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,062 Posts
A few observation about (MY) Lipos......

And all of this is IMHO......

I have seen many that say that there lipos always balance out to 4.20 if you take care of them, and you have a good charger.

I find this a very open statement. Does this take into account the cycles on the battery, how hard they were discharged????

Here is a average over 2 years on my ThunderPower batteries.

My 6600 mAh 5 cells have had just about 65 cycles with discharging to around 3.70.

Here is what I see after a balanced charge:

Best Packs:
Cell1-4.19
Cell 2-4.20
Cell 3-4.19
Cell 4-4.20
Cell 5-4.19

Good pack:
Cell1-4.19
Cell 2-4.18
Cell 3-4.19
Cell 4-4.19
Cell 5-4.19

Worst Pack:
Cell1-4.19
Cell 2-4.18
Cell 3-4.16
Cell 4-4.16
Cell 5-4.17

Now if I take my 2300 mAh 3 cells after 75 cycles:

Best Pack
Cell1-4.20
Cell 2-4.19
Cell 3-4.20

Good Pack
Cell1-4.20
Cell 2-4.19
Cell 3-4.19

Worst Pack
Cell1-4.19
Cell 2-4.18
Cell 3-4.18

I believe that cycles, number of cells, and mAh all play into this. I know some of this is obvious, but I do not see after many cycles how people say they are still balancing all packs even at 4.20????????

My 6600 5 cells take full power for about 30 seconds, and then stays at about 80 amps (40 amps per 5-cell as I have a 10S set-up)...

I have been sharing e-mails with a young (new to electrics kid) and he is just about done with the hobby because of how some old farts have told him he is going to burn down his house.... Sure, we can all have bad thing happen.... But telling him if he has more than a .02 difference in cells will cause the battery to explode is just wrong and dumb......

Have a great day everyone....

DAG
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Old Aug 10, 2012, 09:13 AM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
5,161 Posts
Dag, I agree with you 100%. Voltage differences that small are probably due to the accuracy of the measurement device. Devices (chargers or monitors) look at multiple cells at the same time and each cell has a slightly different set of components measuring the cell voltages. Likewise the charging circuits are seperate and have differnent compents. I don't know of many hobby grade devices made with all of its componenets with a 0.1% accuracy.

If you were truely concerned, you could take a laboratory voltmeter and measure each cell seperately. In my experience, small differences in cell voltage are not that improtant. I ALWAYS balance charge and I ALWAYS storage charge after each days flying session and I still have .01 to .02 difference in final cell voltages.

If I see 0.10 volt difference, I might get concerned and try and cycle the pack a few times and see if it gets better or try to charge that individual cell on a single cell charger.

Is there a fire danger when charging severly unbalanced battery packs? Maybe, but it probably depends on your charger and its protective circuitry. Scaring newbies is not necessary. Telling them to charge in a lipo bag or in a metal box would probably be a better idea.

As for the Nacelle Gap Scandal, Forgetaboutit!!

McD
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Old Aug 10, 2012, 09:27 AM
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bdelapen's Avatar
United States, FL, Pembroke Pines
Joined Aug 2008
2,623 Posts
Hi DAG,

Short version is that this is normal, packs just get old. In the case of LiPos old is a combination of number of cycles and physical age. Also, like anything, higher quality packs age better, lower quality packs age worse. Finally, again with LiPos, usage has a factor in aging, well treated packs age better, abused packs age worse.

So what is an abused pack, well in general there are 3 things to consider: first and foremost, over-discharge (take the cells to a very low voltage, the lower the voltage the worse the effect); hard discharge, the more Cs for longer time the worse for the pack; finally, and this is more relevant with the higher C rated batteries, is storage voltage, you want to store your batteries around 3.8V per cell for better life, it is bad to keep them at a lower voltage but it is worse to keep them at a higher voltage (fully charged).

Now the actual aging (the fact that they are getting old) of the batteries is shown two ways: in the resting voltage after charge, not all cells are created equal and even though manufacturers attempt to match internal resistances of the cells in a pack this will change over time (age/deteriorate differently); final voltage after discharge, more deteriorated cells will also drop farther than the less deteriorated cells.

So, it's rare that a pack goes bad all together, as with any chain it will be the weaker links that goes first. In your case what you are seeing is pretty normal, packs just get old. I would say that any pack in the 3-4 year range has given decent service.

Regards,

- Birger

Quote:
Originally Posted by dag214 View Post
A few observation about (MY) Lipos......

And all of this is IMHO......

I have seen many that say that there lipos always balance out to 4.20 if you take care of them, and you have a good charger.

I find this a very open statement. Does this take into account the cycles on the battery, how hard they were discharged????

Here is a average over 2 years on my ThunderPower batteries.

My 6600 mAh 5 cells have had just about 65 cycles with discharging to around 3.70.

Here is what I see after a balanced charge:

Best Packs:
Cell1-4.19
Cell 2-4.20
Cell 3-4.19
Cell 4-4.20
Cell 5-4.19

Good pack:
Cell1-4.19
Cell 2-4.18
Cell 3-4.19
Cell 4-4.19
Cell 5-4.19

Worst Pack:
Cell1-4.19
Cell 2-4.18
Cell 3-4.16
Cell 4-4.16
Cell 5-4.17

Now if I take my 2300 mAh 3 cells after 75 cycles:

Best Pack
Cell1-4.20
Cell 2-4.19
Cell 3-4.20

Good Pack
Cell1-4.20
Cell 2-4.19
Cell 3-4.19

Worst Pack
Cell1-4.19
Cell 2-4.18
Cell 3-4.18

I believe that cycles, number of cells, and mAh all play into this. I know some of this is obvious, but I do not see after many cycles how people say they are still balancing all packs even at 4.20????????

My 6600 5 cells take full power for about 30 seconds, and then stays at about 80 amps (40 amps per 5-cell as I have a 10S set-up)...

I have been sharing e-mails with a young (new to electrics kid) and he is just about done with the hobby because of how some old farts have told him he is going to burn down his house.... Sure, we can all have bad thing happen.... But telling him if he has more than a .02 difference in cells will cause the battery to explode is just wrong and dumb......

Have a great day everyone....

DAG
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