I'm not suggesting using sabots. I'm telling ya that you can *test* different thicknesses of balsa using a drop test. it's simple kinematics, you can take a hundred gram rod and a brass sleeve, and drop that rod down the sleeve such that it strikes the 'armor' and depending on the height from which you drop it, you will be simulating the same forces upon the 'armor' as if you struck it with a bb of 10 grams moving at x velocity. the equation is (Velocity)= SqRT(2aD) where a= acceleration, which in our case is 9.82 meters/second^2 and D=displacement ie the amount of distance the rod has to travel in order to accelerate to that given speed. so let's go with 45.72 meters per second (150 fps) as our desired velocity for our ball. v and a are known (v^2)/2a = d 2090.3184/19.64 = 106.43 meters that's how far you would have to drop the 10 gram bb to get to 150 fps, imparting that 10.45 joules of kinetic energy, or 457 kg*m/s of momentum. Now obviously, dropping a bb from a skyscraper is silly and impractical. But our objective is to accomplish the *work* of that ball. both KE and P(momentum) are functions of mass and velocity. so let's substitute in our 100 gram rod to get the velocity we need to accomplish the work of the 10 gram ball 10.45 joules=[(0.1kg)(velocity^2)]/2 [2(10.45 joules)](0.1 kg)= velocity^2 SQRT([2(10.45 joules)](0.1 kg))=velocity=14.457 meters per second Now we go back and plug that into our kinematic equation to get the drop distance (v^2)/2a = d = (209 m^2/s^2)/(19.64 m/s^2)= 10.641 meters. Now *that* still looks bonkers too. that's nearly 40 feet high. but remember, my numbers for the mass of both ball and rod are 10 grams and 100 grams simply to make the math easier. the ball is likely to be about a gram or two, so that will likely reduce all of these displacements by a factor of ten. Shotgun guess, you could drop a rod from about 2-3 feet to accomplish the same work. just get me the rod mass and the ball mass and I can do the calculations to get us some solid results.
For discussion sake, a standard .177 is .35 grams. A ‘heavy’ 6mm airsoft bb is .25 grams, standard is .12g. I don’t think it is going to be as challenging to convert.
Right on! yeah a fastgun drop test will work for that just fine, and I think you're right that an AEG should be able to sling that. the velocity results will be pretty amusing though
Also of note as was brought up earlier that airsoft bb’s are larger, not by much. A .177bb is 4.5mm (god why can’t we just officially adopt metric already..) and airsoft bb’s are either 6mm or 7mm. We are not talking a substantial size difference along with the minuscule weight difference. All of that maths should really be negligible for effective balsa perforation. Getting into the larger calibers, ¼” would be a task but I bet it would be doable with some engineering.
I used to have a velocity table for the various Big Gun calibers, but I can't seem to find it anymore. IIRC 1/4" is fine at 165 fps. This corresponds to the safety test for ANSI Z-87+ safety glasses, which are required in this hobby. A .177" bb is also OK around 220-ish fps. I don't remember what the numbers were for 3/16" and 7/32" rounds, and I have absolutely no idea what velocity would be OK for a 3/8" ball. The largest I have ever seen someone experiment with was 5/16" and the damage that thing did to balsa was horrifying. For torpedoes, my recommendation would be to load two or three rounds down the barrel. That tends to yield larger holes when you hit above the waterline or better penetration when you hit below the waterline, but keeps the ammunition simple and within known performance specs. Anvil_x, would you mind posting the formula for converting between armors? The difference in density between a steel bb and a plastic airsoft pellet may not feel like much, but for a cannon it is quite substantial. Greater mass means more force required, and smaller diameter means less force applied for a given pressure. It's a double-whammy. The most common Big Gun shots, 7/32" and 1/4" are slightly smaller/larger than the standard 6mm airsoft pellet. It has been over a decade since I looked at AEGs. Even then the ones I looked at were remarkably low-powered compared to the competition-grade guns of the time. The technology has come a long way since then, and I am very curious how well it would work with modern hardware.
yeah gimme a sec, I gotta track it back down again. If I can't find it, I can extrapolate by performance
here's a super-detailed chart and narrative. http://www.navweaps.com/index_nathan/metalprpsept2009.php still trying to find the source stuff I found early this morning
this one's more palatable. it has differences between the armors by a clear percentage: https://www.navalgazing.net/Armor-Part-1 Mild steel and Compound armor were 25% more effective than wrought iron Nickel Steel was 5% more effective than Mild/Compound Harvey was 15-20% better than Nickel Early Krupp Armor was 15% more effective than Harvey So. wrought iron has a value of 1 Mild/compound: 1.25 Nickel Steel: 1.3125 Harvey: 1.509 to 1.575 Krupp: 1.735 to 1.811 I think that gives you a decent approximation.
I was thinking Kearsarge or the Texas of the period time. I still have the 3D model for the USS Kerasarge I made in Delft ship.
yeah I thought about Texas too. it's a manageable size, has a doable number of secondary guns, that bow torpedo launcher for an epic ram-punch combo, and the en echelon turrets just look fun. the later American PDNs would be bonkers to set up because they're bristling in secondaries. eight to a side in some cases I think some of these boats would have the vast majority of their combat power in their volume of secondary fire, and the long reload time of the main guns will enable that. Which is really cool. Speaking of which, some Plans: https://www.building-model-boats.com/model-boat-plans-store.html
I've modeled the Maine and the Texas in fusion - actually printing out the Texas in RC config at the moment - but haven't touched the later US ships from the pre-dreadnaught period yet. The 'en echelon' arrangement of the turrets in the Maine and Texas would be interesting and challenging. I think some of the other ships like the Iowa, or Indiana Class are quite spiffy as well with their secondary turrets. One of the things I've been wondering about is the possibility of making the turrets penetrable - perhaps having a thin membrane on the inside with electrical traces that, if broken by a projectile, would open a normally close circuit via a solenoid that would render the turret incapable of firing (doable if an AEG solution becomes a reality).
lolololol I'd never aim that high to begin with. I would suggest not doing something like that. it will fail or malfunction.
Yes. Know what also got out of hand? My Timber crew made a screw up in the boundary of a red pine stand. My pre-sale forester then screwed up the map making part, and Today, I found out that we almost compromised an Archaeological site out of sheer corner-cutting stupidity. Oh, and a single male Northern Goshawk built FIVE nests in another timber sale that effectively killed the operation. Which is cool because the hardwood markets collapsed, so the logger's gonna be thrilled to have us take that Albatross of a hardwood sale off his back. This thread is one of the most entertaining side quests I have seen in at least a year. the rabbit hole is deep, and I'm here til we get to the bottom.
