Mr. Tittles

I think some thoughts about maps and map reading are in order. One does not make a map with contour lines ( a map is a two dimensional representation of the earths 3 dimensional surface) so that anyone can tell if they have LOS from one spot to the other. In fact, if a map with 10 foot incremental contour lines was accurate to withing 1 inch elevation (hah!) for those lines, it STILL would not allow anyone to say with certainty if one point had LOS to another. The contour lines are meant to show the lay of the land. A good map reader will look at a hill and be able to tell that there are gullys leading up to higher elevations and in sparsely wooded areas, he will know that the vegetation is seeking water and lower terrain is present at that elevation. The non-3D elements on the map like houses, crossroads, etc ARE surveyed and very accurate. The reason being is that maps are the main means for directing artillery. The lat and long elements of a map are very prcise and the corners of the map (which is not always a perfect square or rectangle) need to be dead nuts accurate. Most pre-computer age maps are made with over lapping aerial photos. The two photos are put next to one another and a stereoscopic vision device allows you to see in 3D. The contour lines are then determined by focusing the 3D at certain levels. Buildings are particularly important also. The maps I made showed actual building shape and size. They are used as land marks and things like graveyards, churches, etc are marked on the map and the legend. The technology I used is the same as WWII. Of note is that while the much wanted contour lines are not in the game, gamey surveying is! I will highlight an enemy unit and then go all over the map and see if I can see its highlighted form from different vantage points. There is no reason that a player should be able to drop down to level 1 and 2 when he has no troops closeby. [ May 02, 2004, 07:23 PM: Message edited by: Mr. Tittles ]

Is this directed at my last post? I neither mentioned resolution nor accuracy. Ive made maps and that map is as good as one that could be expected till about the mid 80s or so. My post shows what a combat commander in this particular situation might have. And as I have said, its pretty good. Since you seem to be a student and someone with limited real world technical experience; would you explain what you mean by resolution or accuracy or how they can be confused?

http://www.ww2dday.com/zoom/zoom_east.html This website has an example of a WWII map. This map shows elevation lines in increments of 10 (ft? yds? meters?). In any case, its as good a map as anyone would make right up to the mid 80s. It would be great if you could go to an overhead birds eye view and just see different colors for different tiles at different elevations. I just want something that I can look at when starting a scenario to quickly get me situated.

I believe I read that a German shreck could be produced in 10 man hours or so. Most small shops could manufacture them so there was no precision machining going on. I think in 42 the PIAT certainly was a good weapon to replace the Boys ATR. But by 44, the well developed US bazooka with its improved ammunition was a much better choice for infantrymen especially. The weight alone is a deal maker to me. Its an easier weapon to train on and had to be more accurate than the PIAT simply from the comparison of the length of travel the projectiles take. The PIAT bomb basically was guided by the short length of rod that comes out into the trough. The bazooka had the full length of pipe to accelerate into. Perhaps the PIAT should have been relegated to armored troops and engineers that specialized in house to house fighting.

Ive never heard of anyone doing that when they say the PIAT was used as a ad hoc mortar. They basically are saying it was used with its assigned round in a high trajectory. The US did have a method of using 60mm mortar rounds from rifle grenade launchers. I imagine that the warhead was not propelled by the mortar rounds own charge but just fixed onto the grenade launcher tail and it would detonate on target. Short range but very effective at house busting, etc.

2.36 inch H.E.A.T. rocket, M6A3—standard: range 600 yds. , 3.4 lbs. weight of round, fired from M1A1, M9, and M9A1 launchers propellant was 0.136 lbs. solvent extruded double base powder, 0.375 inch O.D. by 0.08 in. I.D. by 4.15 inches long (Drawing in 1944 Catalogue, p. 594) (Above is from an unexploded ordanance report.) http://www.rt66.com/~korteng/SmallArms/arms.htm#weapons Rocket: M7A1 shaped charge,rocket motor ignited electrically 3.5-pound (1.6-kilogram), length 19 inches. (Above is from Korean War website. This is an improved rocket supposedly) In any case, its around 3.5 pounds from these sorces. Its caliber was 60mm and it had a hollow charge warhead. I think that 6 pounds is not correct for the weight.

I say give me a map at the vertical elevation. It doesnt matter if its super accurate but should give some rough elevation lines. Something so I can quickly assess the general lay of the land. The contour lines should only appear when looking at birds eye view of the maps. If the graphics could possibly be improved to convey what is seen at lower levels, that also would be good. Many games 'light up' the terrain a unit can see when it is selected. The use of the LOS tool is just a eye strain. The germans were shocked at some of the maps the US paratroopers were carrying. In many cases, they were better than the germans! Ive used those stereo scopic setups with over lapping aerial photography. Its the ability to focus and not get vertigo that is important. In any case, the game needs playing aids. If the battlefield commander had SOME kind of two dimensional rendering of the earths surface available, the player should also. If the player has to make decisions on what the units see, then something better than the LOS tool is needed.

I have seen different penetration figures for the PIAT. The bazooka is said to have 3 inch penetration in the early rockets and 4 inch in later rockets. Is the PIAT penetration 75mm?

http://www.arnhemarchive.org/Photos/PicPiat1.htm Comparing the rod at full throw in this pic with the cutaway of the bomb in a previous post, it seems that the rod may barely make contact with the bomb body. Iy may just extend enough so as to crush into the propellent itself. So a loaded PIAT weighs in at 35 pounds and a loaded bazooka is 24 pounds? A bazooka man could carry two extra rounds and be at the same weight then. Note: The bazooka round may actually weigh less. See later post. [ May 02, 2004, 11:37 AM: Message edited by: Mr. Tittles ]

Was the bazooka ammo that much heavier than the PIAT? Arent they both about the same? The extra weight of the PIAT bomb probably came from needing stronger, more expensive, construction to withstand being speared by that rod. I think the later model bazooka with the two part barrel, advanced copper cone HEAT round with rounded nose, magneto firing was a much better LATW.

Dont believe everything you read on websites... http://www.geocities.com/Augusta/8172/panzerfaust13.htm Firing the weapon is no less of a problem: the trigger can only be pulled using all four fingers. Then the firing pin hits the procectile in its rear, where a small charge of propellant is detonated. The latter makes for a recoil that will cock the spring automatically for the next shot - if the gunner can't take that recoil - which was reportedly not too seldom - he will have to load the weapon again in the way described above. The projectile leaves the weapon at a Vo of 135m/s but accelerates in flight. Accelerates in flight? Yeah right! [ April 30, 2004, 09:18 PM: Message edited by: Mr. Tittles ]

The propellent provides the majority of the energy to accelerate the bomb to its velocity. Not some, mind you, but the majority (like in vast majority). Ooomph and Kick and whoosh aside, the math does not add up. Newton knows that the spring/rod also takes away as much as it gives. The propellent is doing double duty. From a manufacturing standpoint, the bazooka is incredibly cheap compared to the PIAT. The PIAT spring is expensive, the rod must be machined, the bombs internal cavity must be within a tolerance (since it acts as a barrel). The whole thing is heavy and awkward and I suspect does not compare in accuracy with a bazooka beyond 25 yards or so. The bazooka tube was not machined. In fact, later bazookas were two part barrels. The rockets were cheap to make also. the Brits could have made thier own or traded APDS for some. [ April 30, 2004, 09:17 PM: Message edited by: Mr. Tittles ]

http://www.inert-ord.net/atrkts/bazoo/

The site does mention a lag between unleashing the trigger and the bomb taking off. Pulling the trigger on this thing means unsnagging that spring. It also mentions that the firer has to grip that trigger guard stiffly and that there is a limited number of positions the firer can be in. A bazooka firer can pop from behind a wall and firer with no recoil. The firing is electrical and there is no lag really. He can be in standing, kneeling, etc. He can fire with one hand actually. The PIAT gunner really has to be prone on the ground or have the monopod resting on something. [ April 30, 2004, 01:22 PM: Message edited by: Mr. Tittles ]

http://www.btinternet.com/~ian.a.paterson/equipinfantry.htm This website claims a velocity of 250 feet per second. Even using flaming knives calcs above (which assume complete travel under spring effect), the spring would contribute 7 percent of the final velocity. In actuality, its probably less. The weight of the rod and bomb may be very close btw. I am sure there were dummy practice rounds that could be used to practice loading (dummy meaning no HC or propellent. If one were to squeeze the trigger, I guess the dummy would shoot out at some small velocity. [ April 30, 2004, 01:11 PM: Message edited by: Mr. Tittles ]

Its more like you are at the end of a pier waiting for this small boat driven by a midget (total weight of boat and midget equals your weight) to come at you (90 degrees to the pier end). As it arrives, you leap on and not only propel yourself forward considerably, you have to reverse the boat (reverse it so it goes back to its starting point). The thing is, when you jumped on the boat, you increased it mass and it did not maintain its speed. It also ran out of gas (end of spring travel). So you would have went much further if you had just jumped off the solid pier. So, yeah the propellent charge has the energy. The firer of this weapon had to hold the thing against any remaining kick or it would not cock. That means the total weight of firer and weapon is a very large mass compared to the bomb. But not the same ratios you see in a rifle or a artillery piece. Its orders of magnitude different. If the spring/rod did not take up the energy back into the spring, the firer would be broken. [ April 30, 2004, 11:48 AM: Message edited by: Mr. Tittles ]

Its showing that theres no free lunch. The basic thought is that ANY forward velocity component FROM the spring/rod may be negligible compared to the cost (it DOES take energy to get the spring ALL the way back) from the propellent energy loss. I think that flaming knives sees that the spring is not acting for more than a fraction of its travel. I dont know if comparisons to 303 bullets can be made due to the different length of barrel, etc.

This pic shows the cutaway. The rod has to travel up the hollow to reach the propellent. If this is a 90mm round, that internal propellent cavity is over an inch in diameter. It appears the propellent is as long as it is tall. I would say that is more propellent than a typical rifle round has. perhaps twice as much? [ April 30, 2004, 01:07 PM: Message edited by: Mr. Tittles ]

What 'distance'? Are you asking the throw or travel of the rod perhaps?

From images in this and other websites I would say that the throw of the rod compared to the depth of the bombs inner chamber does not allow the spring to even act as a pushing mechanism for more than a few inches at best. And this at the end of its throw where the spring is weakest usually.

The propellent reverses the rod. It would normally propel the bomb but must propel both the bomb and the rod (in opposite directions). So there is no free lunch. Getting the rod back takes away energy from the bomb. Any way you slice it, the spring is not contributing much to the forward velocity of the bomb. Its bad intuition at work here. People see a spring and must understand it as a launching device. The fact is that the bomb is contacted at the end of the throw of the spring/rod system. The springs energy has already been put into the rod before it strikes the bomb.

No. Theres a big point in having the mass of the rod and the large spring also. F=Ma The propellent acts on both the bomb and the rod. Each is sent shooting in opposite directions. The rod is buffered into the spring. If not, the poor firer would be busted up horribly. The main point of the spring is to stop the rod, not 'push' the rod so that it heaves the bomb. The bomb is heaved by the propellent.

The cutaway drawings of the bomb show that the propellent is inside a cylindrical area inside the bomb. When the spring is cocked, the rod is back. In other words, the rod must come forward into the bomb to get to the charge. I made a point earlier that the energy of the rod actuated spring may not be transfred to the bomb. That is, the charge launches the bomb. When the bombs cylindrical area moves off the rod, the backblast would basically be pointed in a cone rearward. Part of that cone would be headed towards the firers face. [ April 29, 2004, 05:06 PM: Message edited by: Mr. Tittles ]

I doubt that the bazooka tube was machined. It was probably a sheet of metal that was rolled to a diameter. Since there is no rifling, it would only need a semi-crude finish. The PIAT rod and bomb relationship is a close tolerance. Its very similar to an unrifled gun. The bazooka and rocket relationship is just a guide tube. The PIAT needs some assurance of sealing to get a repeatable velocity performance. The rocket in a bazooka produces its own velocity and the tube merely provides a guide for forward acceleration. The PIAT would have to outperform the bazooka in penetration to justify itself and its weight. [ April 28, 2004, 11:00 PM: Message edited by: Mr. Tittles ]

I would fault the PIAT with being heavy and probably innaccurate. It needed that spring which is certainly expensive to make (compared to a tube). Some sources claim firing took multiple fingers. This cant lead to any precision shooting. Its much cited 'lack' of backblast (but not a top blast) does not make up for its weight. Unless its penetration was significantly better than the bazooka, then the commonwealth troops should have used the bazooka. Perhaps they should have been issued with a Bren Gun PIAT-Tripod?