RC Tank Warfare community hobby forum

Hi, thanks Carl.

Now, back to the fighting compartment. The main parts of the floor tread plates, shaft and the trails have been installed. I have decided to redo the trails using Plastruct 90519 11mm I-beams. The resin kit part were only I-beams on one side, not good enough for me. But I was able to reuse the shaft after modifications. Contrary to the kit parts, the gun shaft of the M7 is not held in place by a central pin in the hole, the shaft is tightly fastened at both ends to the floor and this is reproduced here. The plan is to use the now available central hole for gun elevation using a push rod. This is a howitzer so elevation will get priority over gun rotation. There is limited space below deck so I have not figured that yet.
View from above. The gun shaft central hole is positioned according to references. If you remember some initial posts, the kit parts were positioning the gun too much on the right. Take note that the angle on the shaft is no mistake. Its like that on the real thing. I took the angle from 1/35 kit.
A lot more details will go into the floor and walls.
Did my best to capture the shapes and angles of the trails from ref pictures.
These still require some adjustments and details but you can see where this is going.
Some detailed reference pictures from Squadron Signal M7 Priest walk around. I tried my best to do something similar. However, I can notice some differences in arrangement between restored M7 so there is room for some interpretation. I will replicate the bolts on the sides.
So far, I like this build. What I do here is because I want to do it. I admit that I have a lot more fun converting and improving this resin kit than building a $800 Tamiya kit. What is nice about this type of modelling is that it creates unique pieces, and no matter what, there will be no other M7 exactly like it.
Regards, Louis

Louis it's much like a history lesson watching this build. Had no idea the gun was angled that way on purpose. Your I beam construction is very good to look at and is strong and functional. Having one of a kind pieces is very rewarding for sure what I find most remarkable about this is you're doing it on a strict budget all the while!

Great work and a fantastic guide for anyone who builds this kit in the future. Its a shame the kit designer didn't put in the same level of research on the details before creating the molds.

Hi,

This is the planning phase for the M2 105mm howitzer.

These are the main kit parts for the gun.
Basic dry fitting and playing with the part shows that something is definitely wrong with the size of some parts. It looks like an M2 howitzer all right but compared to reference pictures, I can see many important things such as the elevation pivot on the cradle is not at the right location in relation to the breech no matter what I try. Analysis is required to determine which part exactly is wrong. It is important that the gun is well positioned because it will impact the overall look and feel of the model.
First, the gun tube itself. It looks good. My calculations indicate the length with the breech should be 160mm, kit part is 156mm and within my 5% tolerance. The gun has a central metal tube and is strait. The breech came separately and is now glued. Tube size is also ok for a 105mm.
The cradle should be around 168mm long and kit part is 173mm, better too long than not enough, it can be cut later. It is devoid of much details, which is of a disappointment. The pivot for elevation is definitely not at the right location and will need to be sanded and rebuilt at the right location. No big deal.
The sleigh and recoil assembly parts. I have determined that these parts are the main culprits. The sleigh should be 83mm, it is only 70mm and is not well detailed compared to the original. Same for the recoil tube, it should be 94mm long and is only 84. So, I will need to rework these and improve their look. It is important for me because these are very visible parts. You can forget about using these parts for RC recoil.
As for the base of the gun, well... kit parts will not be used and the whole thing will be scratch built with plasticard using pictures and my 1/35 scale kit as reference, a challenging task that should keep me busy for a few hours.
Regards, Louis

It's fascinating to see you come up against the limitations of these kits and then engineer top-notch scale solutions, Louis. Looking forward to seeing how you tackle the gun mount.

Seem to be a lot of inaccuracies. Bearing in mind what their web site says "Detailed replica and high quality distinguish the model. Please note that might need to be reworked parts." The last sentence is more appropriate than the first. It's not cheap and i would have expected much better for the money. All credit to you for the great work you are doing in correcting the errors.

Thank you very much for the pictorial step-by-step on using the Shapeways M3 bogie parts! I have been considering if the $50 required was worth it; but think a lot higher about it after seeing your work. Very helpful, so thank you again.

sassgrunt wrote:Thank you very much for the pictorial step-by-step on using the Shapeways M3 bogie parts! I have been considering if the $50 required was worth it; but think a lot higher about it after seeing your work. Very helpful, so thank you again.

Much agreed

Hi, thank you,

I see this kit as a basic one, providing the main parts, leaving the building to fill in the rest. I personally prefer it like this because the few details they put in are usually wrong and need to be removed at extra work. The M7 however is tricky because there are very few add on parts on the market.

Continuing with the gun

A new sleigh is made from plasticard, with general dimensions taken from 1/35 kit and increased to 1/16 scale using the formula; (plastic kit dimension divided by 0.02857142) then divided by 16. But then the part need to be adjusted to the situation of the moment with the resin kit parts interfacing with it, keeping proportions right and adjusting for issues. The sleigh is given rails so that it can slide on the cradle. I will not give it rc recoil but I do not want a glued howitzer either. One of my first kit in the 70s was a 1/40 Life Like M-101 howitzer, and I was amazed by the recoil... I find it wrong to have produced a gun on this large scale without giving it recoil considering the low complexity involved. Note the difference in length.
All features on the cradle have been removed to create better ones. The part was not strait so 20 seconds in the microware did soften the resin just enough to be made strait before cooling off. I have found the use of the microwave works better when a whole part need to be heated. Localized sections however are better heated over a boiler.
Kit parts like the rings and the tip of the recoil tube were reused. I did not have 7mm brass tubes for the recoil tube so I looked around the work area and found that the larger section of a Heng Long control antenna is of the perfect size. I must have like 40 of these unused HL controls in a box. Good to see something from them being useful again.
How the recoil tube fit the rings is left to the builder to figure out. It takes some time and effort to get it right. Once painted with primer, these will require another round of fine tuning with putty and tools. This is complicated by the fact that no restored M7 seems to look the same. So, you need to pick one vehicle and stick to it.
The gun sleigh slides on the cradle pretty well. All parts looking strait. The gun is missing a few mm but I will leave it like that.
Taking close up pictures of a model in construction is an important step. On the pictures, you can always see things to improve that are difficult to notice with the naked eye. I will polish this gun for quite a while before I am fully satisfied.
Here, if you look at the picture under the part, you can notice that the kit gun tube is missing quite a few mm in the section that connects it to the breech. I left it like that and had to adjust the back end extension of the sleigh accordingly. Other cradle parts will be added later once their best position has been determined from dry fitting them with the gun mount and hull.
Next, the gun mount.

Regards, Louis

Hi,

Here is a rainy weekend project, an M7 Priest gun mount.

From what I could see, there are at least 3 models of M7 gun mounts, completely different between M7 early/mid, M7B1 and M7B2. The upper section coming with the Vandra kit is actually quite close to the M7B1 I have seen on pictures and my feeling is that it could be a good base for a build of that version. However, I needed a mid production one so need to scratch build one. The kit lower section is useless unless you are building a fighter and do not really care about the interior accuracy.

Small plans are drawn as extrapolated from 1/35 scale kit to get the right dimensions to start with. This is critical. Basic shapes of the lower and upper parts are created. Gun mount is built in the old fashion way with 1, 1.5 and 2mm plasticard sheets, knife, files and metal ruler. Parts are bigger here than they need to be, they will be slowly sanded to the proper dimension to avoid mistakes and allow for fit trials.
Basic assembly
Upper base starting to take shape
The upper and lower parts in test mode. The gear dents from the resin kit were reused as I could not make better ones, extended by mine where they won't show much. The final detailing with bolts and other items will come later in following posts. At this point, you just need to make sure the main parts dimensions are good.
Interior views; The gun mount is assembled and mounted on the shaft/axle. It rotates as per specs for gun rotation. Because the M7 gun can turn in the right direction more than on the left, now I fully understand why the shaft was created at an angle.
The gun and intricate mount are the highlights of this SP howitzer so I wanted to do a good job capturing the shape of the real gun mount. The whole thing took me 10 hours to build. I had to constantly check dimensions and positions against references. View from the right side
View from the front on the rotation mechanism, quite simple. Temporary installation as it should have a brass tube. This won't show later once the gun is installed. The tube is going all the way down under the floor and a gun rotation system connected to it will be brainstormed later. The center of the tube will carry a pushrod for elevation. Maybe its too simple... well, that's the plan anyway.
Here is the M7 Priest trialling its new M3 Lee modified Shapeways suspension. These and the spoked road wheels are really nice. Too bad spoked idlers are not available.
So far so good, all is going according to plans. Test fit of the kit gun shields show that the location, fit and overall integration of the various modules is good. That is a load off because although I took my calculations from a 1/35 that I can see and touch, potential major mistakes are always lurking.

Regards, Louis