Author Topic: A What If Amphibious Vehicle  (Read 6907 times)

Offline PFJN

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A What If Amphibious Vehicle
« on: May 15, 2023, 09:02:56 AM »
Hi,
I;ve started work on trying to build a 1/35 scale model of a "what if" idea that I had.  Right now I'm still playing around with some ideas, but the image below shows kind of what I am thinking.

The thought is to take a commercially available turret and main gun and put it onto a tracked vehicle hull that has some degree of amphibious capability.

Right now I am looking at usinga 3D model that I downloaded off the internet of something called a Cockerill 3105 turret.  Although the Cockerill 3105 turret is desined for weapons up to 105mm, from some of the stuff that I have read on the internet it can also accomodate a 90mm gun.  As such, I am thinking of fitting with a rifled Cockerill 90mm Mk 8 gun which, as I understand it, can fire a range of ammunition including an Armor Piercing, Fin stabilized, Discarding Sabot round, a High Explosive Plastic round, a smoke round, and a barrel launched anti-tank missile called the "Falarick".

Right now I am using the current 3D turret model as a place holder, and I hope to use it and other info off the internet to put together something that I might be able to 3D print at a 1/35 scale for my model.

Later I want to look at adding propellers or waterjets on the back end of the vehicle and some sort of ramp forward.

Regards

Pat


Offline Frank3k

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Re: A What If Amphibious Vehicle
« Reply #1 on: May 15, 2023, 09:29:50 AM »
The HobbyBoss LAV-150 with 90mm Cockerill might be source for the turret.

Details on Scalemates


Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #2 on: May 15, 2023, 10:21:57 AM »
Hi,
Thanks for the suggestion.
Pat


Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #4 on: May 16, 2023, 01:02:28 AM »
Hi,
Thanks.  I think I may have an unbuilt Hobby Boss model of this kit somewhere that I can try and use as a reference.
Pat

Offline Story

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Re: A What If Amphibious Vehicle
« Reply #5 on: May 16, 2023, 07:11:29 AM »
IIRC, that V150 turret looks too small for your concept
http://beyondthesprues.com/Forum/index.php?topic=9083.msg169654#msg169654

How about a Cadillac Gage 105 Stingray turret?  They didn't crack like the hulls did.


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Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #7 on: May 17, 2023, 09:20:28 AM »
Hi,

I think that may be the turret that I am currently using.  I am trying to convert it from a 105mm gun down to a 90mm gun, like shown in the video.  The relatively high angle of elevation (+42deg) shown in the video seems like it could be useful in an urban or semi urban environment including some of these artificial fortified islands that are getting built in the South China Seas. (https://www.scmp.com/news/china/diplomacy/article/3198504/fortified-south-china-sea-artificial-islands-project-beijings-military-reach-and-power-say-observers)

I have also added a rugh idea that I have for a bow ramp.

Regards

Pat




PS.  I still need to reduce the size of the aft turret overhang, which looks like it can be made smaller for a 90mm magazine, as shown in the video in the previous link above.
« Last Edit: May 17, 2023, 09:22:10 AM by PFJN »

Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #8 on: May 19, 2023, 12:09:02 PM »
Hi,
I looked around on the internet and found some images of an external hydro-pneumatic suspension unit from a company called Horstmann that I used to make up something kind of similar in 3D CAD, that I hope to 3D print for my model.  Apparently this type of suspension is similar to those used on other amphibious vehicles and allows the road wheels and treads to be retracted up when the vehicle is in the water.



Regards

Pat

Offline LemonJello

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Re: A What If Amphibious Vehicle
« Reply #9 on: May 19, 2023, 09:36:01 PM »
Enjoying the development work going on here.

Offline Frank3k

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Re: A What If Amphibious Vehicle
« Reply #10 on: May 19, 2023, 10:21:26 PM »
Does the bow ramp fold up to conform with the front o the vehicle? It might make a good armor shield when not in the water.

Offline apophenia

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Re: A What If Amphibious Vehicle
« Reply #11 on: May 20, 2023, 02:23:26 AM »
... an external hydro-pneumatic suspension unit from a company called Horstmann ...

Excellent choice Pat  :smiley:  That's the Horstman InArm HSU as used on the Puma, Mobile Protected Firepower demonstrator, etc.

-- https://horstmangroup.com/horstman-products/horstman-inarm/
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Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #12 on: May 20, 2023, 07:48:47 AM »
Hi,

Thanks for the feedback everyone.  For the ramp, I'm still working on it, but its based on something that I mocked up previously in cardboard.  It's supposed to be hinged and articulated to be more boat like when deployed but flatter when retracted.

Pat






Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #13 on: May 25, 2023, 12:16:44 PM »
Hi,
I've been working on updating some of the dimensions, escpecially in way of the suspension and tracks.  I've been trying to model the tracks to be similar to some of the newer composite band tracks like those made by a company called Soucy.  Below is an image of where I currently am.  I still need to modify the drive sprocket to mesh with the new tracks, and I also messed up my measurement just a little leaving me off by about half a "pad" width, that I still need to fix.

Hopefully things are moving along though.

Pat


Offline Buzzbomb

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Re: A What If Amphibious Vehicle
« Reply #14 on: May 25, 2023, 01:24:10 PM »
Interesting approach, so far looking very good

Offline GTX_Admin

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Re: A What If Amphibious Vehicle
« Reply #15 on: May 26, 2023, 01:35:52 AM »
I've been trying to model the tracks to be similar to some of the newer composite band tracks like those made by a company called Soucy. 

I have had discussions with this company in real life - some interesting stuff they do.
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Offline apophenia

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Re: A What If Amphibious Vehicle
« Reply #16 on: May 26, 2023, 05:51:02 AM »
... I've been trying to model the tracks to be similar to some of the newer composite band tracks like those made by a company called Soucy....

Another excellent choice  :smiley:

Soucy Bandtracks: Quebec snowmobile gits make good! C'est bon, non?

I have had discussions with this company in real life - some interesting stuff they do.

Greg: Any idea if the neighbours at Camso (Camoplast/BRP as was) represent a genuine rival to Soucy? The Michelin acquisition of Camso would seem to add credibility. But Soucy has a hell of a lead!

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Offline GTX_Admin

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Re: A What If Amphibious Vehicle
« Reply #17 on: May 27, 2023, 01:13:26 AM »
Greg: Any idea if the neighbours at Camso (Camoplast/BRP as was) represent a genuine rival to Soucy? The Michelin acquisition of Camso would seem to add credibility. But Soucy has a hell of a lead!

Not sure to be honest.
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Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #18 on: May 29, 2023, 01:29:08 PM »
Hi,
I still need to modify the drive sprockets, but the images below show what the tracks and suspension would look like with the tracks in their operational position and with the suspension, roadwheels and tracks retracted for operations in water.

Pat




PS.  Unfortunately the above images aren't to the same scale.  But overall the Idler is pushed back about 11cm (I think) when the tracks, roadwheels and suspensipons are retracted.
« Last Edit: May 29, 2023, 01:39:10 PM by PFJN »

Offline kim margosein

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Re: A What If Amphibious Vehicle
« Reply #19 on: June 02, 2023, 10:36:45 AM »
When the track is retracted, how do you take up the slack?

Offline Old Wombat

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Re: A What If Amphibious Vehicle
« Reply #20 on: June 02, 2023, 10:50:02 AM »
When the track is retracted, how do you take up the slack?

PS.  Unfortunately the above images aren't to the same scale.  But overall the Idler is pushed back about 11cm (I think) when the tracks, roadwheels and suspensions are retracted.
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Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #21 on: June 05, 2023, 06:40:02 AM »
Old Wombat,
Thank you for calrifying that for me.

Lately, I have gotten a little off track, trhying to figure out how a vehicle like this will drive either its tracks or its waterjets (when in water).

In looking at information on the canceled EFV program it looks like they used a regular gearbox driving the final drives to the track, but added in some sort of "splitter gear" between the engine and the gearbox that could be used to clutch in the waterjets and clutch out the main gearbox (if I am understanding correctly) as shown in the following links

http://www.army-guide.com/eng/product2418.html
https://www.fire.tc.faa.gov/2007conference/files/Materials_Fire_Safety/WedAM/GwynneMagnesium/GwynneMagnesiumPres.pdf

And data on the Korean KAAV II "appear" to show a similar configuration, if I am understanding the images that I have seen. https://blog.naver.com/jhst3103/221397823921

Alternately, I also came across a paper on the US Government's Public STINET site about a "test rig" that was built early in the AAAV/EFV program (I think) that was built to valaidate the ability to retract a vehicles suspension and shift from a "land based" propulsion, to a "seaborne/waterjet" propulsion.  And in that design it appears that the main engine there directly drove two hydraulic pumps which could either drive a hydraulic motor on each final drve or a hydraulic motor on each waterjet, depending if you were operating on land or water. https://apps.dtic.mil/sti/pdfs/ADA205397.pdf

Currently I do not know whch type of set up might be best for a combat vehicle, or if may be some mix of systems might be better.  But for now since I kind of used the M8 AGS as a starting point for my dimensioning I figured that I shouel maybe enlarge the vehicle a bit to account for th extra volume that would be required for a pair of waterjets and this added "splitter" gearbox or hydraulic pumps and motors.

Also, from my reading it looks like many of these type craft will use air cooling for the engine when operating on land, but will have an auxiliary water cooling system for seaborne operations.  I'm guessing that maybe this arrangment may also help with cutting down on the concerns on injesting sea water and spray through the air cooling system whan the vehicle is at sea.

Below is a CAD sketch showing some 300mm diameter waterjets placed aft and the main engine (an MTU 6V 890) and a notional main gearbox (a RENK HSWL 194) located forward. [I really have only used this specific gearbox for now since it seems more or less matched to the engine size I've picked and I was able to find numerous 3D models of it on the internet, and figured that any other gearbox with similar capabilities would hopefully be similarly sized.]

A couple bg concerns right now is just how tight it looks inside (especially in way of the driver and the adjacent gearbos and engine) as well as how big the turret ring is for the turret that I have picked, and the fact that I would need to find someway of getting the "power" from the engine forward to the waterjets aft, without the turret basket getting in the way.  As such maybe a fuly hydraulic transmission system, or a partial one where a hydraulic pump is only used to drive the waterjets, but the final drives for the tracks are still driven by a mecanical gearbox may be an option.

Anyway, I'm trying not to get too far down in the weeds (since my knowledge of all this stuff isn't that great) but I do want to at least try and make an effort so that I can kind of say that I "think" that there may be enough space to do this, and its kind of interesting to me, and a learning experience, to research and look through how other "real" vehicles tried to do similar things.  And from what I am currently seeing, I'm beginning to think that I probably need to make my vehicle a little bit bigger to fit everything it will probably need.  :P

Pat




Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #22 on: June 13, 2023, 11:36:17 AM »
Hi,

Sorry for the delay in making any new posts, I had a couple things around the house that I needed to take care of.

Below is a partial update showing the hull widened by about 300mm and lengthened by about 500mm (if I am recalling correctly).  I think that this will allow for the turret ring and basket to better fit (I hope) and will also hopefully provide some extra internal space for the waterjets, bilge pump(s), water cooling sustem, and the use of a hydraulic otentially electric) transmission system.

In general I have just been taking some stuff off the internet or dimensions from reports for pieces of machinery and outfit that appear to be close to the right size to kind of see if it looks like ev erything could fit into a vehicle the size of what I have shown.  Specifically the information for waterjets in the model come in part from info in a report on an amphibious test craft (called the Automotive Test Rig or ATR) that was built awhile ago paired with part of a waterjet 3D model that I found on the internet and scaled to the dimension in the report.  One of the things that I realized since I last posted anything was that the waterjests used on the ATR had two stages of blades, so I updated my model accordingly as shown below.

Additionally I also found some information on the internet for a splitter gearbox with a clutch (shown in dark blue below) to connect the main engine to two hydraulic motors (which I am still in the process of trying to model).



Overall the final system should look kind of like this sketch for the ATR taken from the report ADA205397.pdf - Automotive Test Rig Final Design Report.



Regards

Pat

Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #23 on: June 14, 2023, 12:54:16 PM »
Hi,
Here's a quick update showing the hydraulic pumps and motors.
Regards
Pat

Offline PFJN

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Re: A What If Amphibious Vehicle
« Reply #24 on: June 21, 2023, 12:59:00 PM »
Hi,

After messing around with stuff for awhile I finally seetled on a length for the hull of about 6.35m (20.83ft), a width of about 2.99m (9.8ft) and a height of about 1.24m (4.1ft), and a ground clearance of about 0.41m (16in), making the top of the hull about 1.65m (5.4ft) above the ground.  I think that this should hopefully be able to fit all the large pieces of outfit and equipment, with some space left over for the smaller stuff I don't really have the ability to try and figure out.

With the longer length I've added one additional road wheel and one additreturn roller per side.  And I still have to redo the tracks, and maybe the drive sprocket to match.  Othe than that I still need to clean up the lower back end to try and keep it from hitting the ground when starting up a slope, and to also accommodate the waterjets better.

In addition, I also want to try and revise the turret to show a 90mm gun and the smaller aft overhang (I think)  that the turret would have with that gun, and also add the turret basket, plus check the gunner and commander's chair heights.  For the driver I have moved his chair to now be on centerline.

Once I get all that done I hope to start laying out the hull for 3D printing.

Pat