Tiger Ausf E “F01” Gruppe Fehrmann

[AlastairCooke]

Hi Adrian
Thanks. Perhaps I should consider designing a 'heat shield' that looks like the fuel tanks?

Alastair

[Ivano Costantini]

Hello Alastair,
from tests carried out in the past, the resin I use begins to deform at 50 degrees.
Ivano

[AlastairCooke]

Hi Ivano
Thanks for the information. I have not completely decided where to put the smoker system(s). I am looking into a vape based design at the moment so may put the units under the turret for easier access.

Alastair

[AlastairCooke]

Hi All,
Update 25 Oct 20
Not much to report as I have spent much of the last few weeks deciding on the position of some of the items in the hull. Currently I am planning to have a servo-driven bow MG, 4 stepper motors driving the radiator fans, a Beier sound system with speakers located under the radiator inlet grills and two smokers each with a high pressure/flow fan unit located in front of the firewall. As a result I intend to install a 24V battery system for the motion (drive motors and turret rotation) and a separate 12V battery for the other services as some, like the smokers, can drawn a lot of current. There will probably be another 12V battery in the turret so that the turret electrics are separate from the hull systems.

I have spent a lot of time reading battery specifications and selected: two Relion RB20-X (12V 20Ah with 50A max continuous) in series for the 24V system and a Tracer 12V 24Ah (30A) or 12V 16Ah (30A) battery for the 12V system. Will not be buying them just yet so things might change.

As I will most likely need to access the hull mounted systems through the turret ring I decided to start assembly of the turret....what fun that was!

Spreading the horseshoe was actually quite easy using a heavy-duty clamp/spreader and the front frame snapped into place. I had checked beforehand that the ‘tongues’ slid into place fairly easily. This was achieved by test fitting the frame from the outside and assuming that the fit from the inside would be the same.

Bolting on the turret base was when the fun really started!
I spent well over an hour trying to fit 8 screws... in the end it was the order that mattered and the length of screws used to get things started. The front centre and rear cap screws were fitted as per the instructions. I then used the other two M4x20 cap screws to line up the front frame before replacing them with some of the M4x16 cap screws. In so doing, I could use the longer M4x20 screws to get purchase in the tapped holes on the rear sides then came two M4x16 screws for the holes at the front sides. Finally, the bolts were swapped around to match the instructions and the turret sides bashed with a rubber mallet and tightened up.

I spent a lot of time thinking that the high tightening torque was due to cross-threading (a definite no-no with steel bolts into blind holes in aluminium) rather than being caused by the cap head pulling into the counter bore and lining things up . In the end, I just went for it and everything came together . There will be a bit of filling and shaping but at least I have a turret to be proud of !

the turret so far...

weapons (tools) of choice...
Quite a long-winded story but useful advice (I hope) for anyone yet to build their Tiger 1 turret.
Alastair

[Vince Cutajar]

Bolting on the turret base was when the fun really started!

I know that feeling.

Vince

[AlastairCooke]

Hi All,
Update 28 Nov 20
Nearly there with the revised road wheel hubs. Just the hub caps to finish...

Rear. Have positioned the axles to show how the rear hubs protect the bearings from foreign object ingress.

Front. Will insert an M5 hex bolt to allow sufficient purchase to be able to loosen/tighten the cap.

I decided some time ago that the sound system speakers would be fitted under the front grills so that the sound would not be masked and come from approximately the right place. I have designed my own speaker boxes loosely based on the upper fuel tanks. The pictures below show them being dry fitted. I have had to design a complex mounting arrangement as I want to be able to get to the rear torsion bars and idlers relatively easily.

20201122_105951-doc.jpg (56.03 KiB) Viewed 3975 times

Speaker box based on shape of upper fuel tanks.

Mounting shelf: can be removed by unbolting from front of firewall.

View through grill. Speaker will be less visible when wire gratings are added.
Continuing with the theme of including basic shapes rather than fine details I have added a plate with a lip to represent the radiator and provide a location for the square head bolts that secure the radiator cover. I will be doing more with the fan units but that is for later .

Shown below, revised engine cover (slightly wider to accommodate resiting of grills)

Aluminium angle added to front roof support. Although this is not proto-typical it will only be seen when the Wanne roof is removed. Having felt the weight of the turret and noting that the roof will be a 3mm steel sheet I decided that the extra strength/stiffness was more important than accuracy.

Will be using button head bolts eventually.
Alastair

[AlastairCooke]

Hi All,
Update 18 Jan 21
I have decided to delay priming, painting and assembling the hull until the spring so that I can spray outside. In the meantime, I have been working on the radiator fans and other internal details.

Radiator fans
As mentioned before the changes made to the rear deck and engine bay mean that the excellent radiator and cooling fan kits available from Ivano Constantini or John Grima (East Coast Armory) would not fit without major reworking. Therefore, I decided to design my own version based on NEMA 8 stepper motors. My plan is to hang the whole assembly from the radiator cover plates... so I need a very ‘stiff’ structure to minimise vibration. The motor support is a 3mm thick aluminium plate sandwiched between 3D printed components. The top one will mimic the shroud and the bottom will provide the support.

Lower support and motor mounting plate. This will be bolted to an angled plate for attaching to the radiator cover.

Trial 3D printed fan (note eight blades). Most PC cooling fans I could find had seven blades (for quiet running?) which would not look correct when stationary.

Trail fit of motor. 3D printed fixture ensures correct positioning and alignment for fans.

Anchor plate and top element attached.

View of top element, will eventually have an etched brass cover plate. Below are views of the complete ‘unit’. The angled plate needs shortening to ensure the fan unit is correctly placed.

This view shows how the unit will be attached to the radiator cover plate. This design means that the fan unit does not require fixings incorporated into the hull sides or rear and can be removed for maintenance.

This shows the fan unit in place, it just needs to be raised by about 10mm . Whilst waiting for a revised angled plate I am ‘playing’ with an Arduino and an EasyDriver stepper motor control board .

Central Roof Support
I have added something prototypical to provide more support for the (planned) heavier (steel) roof.

Thanks for viewing...
Alastair

[Adrian Harris]

People will be beating a path to your door for these parts (me included)

Adrian.

[Vince Cutajar]

Great update Alastair.
I love the simple way of implementing the four radiator fans without using the fan ducts.
Out of curiosity, why are you going to use 4 steppers instead of DC motors? Maybe the steppers are easier to attach to the angle plate?

Vince

[AlastairCooke]

Hi Vince and Adrian,
Thanks for the positive response.
Vince, I chose steppers so that I could more easily ( I hope ) synchronise them with each other and link their speed to the throttle position. There is Arduino code that handles acceleration/deceleration etc. My plan will be to link the fan speed to the start sequence and then the throttle position with a cut-off after a given time so that the fans are not running all the time. When the tank is in motion, with the covers down, the fans will be difficult to see so no need to have them spinning.
Alastair

[Vince Cutajar]

Thanks Alistair, That all makes sense and it's all possible to implement with an Arduino. I changed my recoil to an Arduino / stepper system and it works beautifully.

Vince

[AlastairCooke]

Hi All,
Update 5 Mar 21
I decided that it was important, as I am planning to have animated fan units, to improve the accuracy of the engine deck grillwork.
Radiator outlet grills
First, I cut the bars to match those found on the actual vehicle.

I also milled off the integral hinge and replaced it with a set from Sixth Scale Icons (from Field of Armor)

Using a resin set obtained from John Grima (East Coast Armory) I increased the thickness of the grills to make them more proto-typical.

Resin part will be pinned using 1.6mm brass rod. The actual castings had end ‘caps’ that joined the bars together. This was made from laminated Plasticard that will be pinned to the resin part during final assembly.

Part complete, ready to be pinned and glued to the cover.

Part epoxied and joints ‘smoothed’ with Milliput.

The bottom detail consolidated with several stippled coats of Mr Surfacer 500.

Radiator inlet grills

Standard part

Resin piece from John. This was thinned down to a height of 6mm to ensure the correct overall depth.

Piece adjusted, pinned and epoxy glued to pre-primed cover.

Adding edge detail using Plasticard, also pinned, using 1mm brass rod this time.

Part epoxied and joints ‘smoothed’ with Milliput.
The bottom detail was consolidated with several stippled coats of Mr Surfacer 500.

Finished item prior to priming (red primer)

Fan Units
These have been completed and dry fitted to the radiator covers

Assembly fitted in place. The cap screw heads will epoxied into the radiator cover and blended out using a suitable filler; Milliput or an automotive glazing putty.

General view giving idea of final look.

Thanks for viewing
Alastair

[Vince Cutajar]

WOW.
Great update Alastair.

Vince

[simon_manning]

Lovely work Alistair, save your money and buy a 1 litre tin of cellulose car primer, the thick variety, leave the lid off and it thickens a bit more, excellent for texture coating these sized vehicles and a fraction of the cost of Mr Surfacer and it is the same stuff just re bottled, superb build, regards simon manning.

[Alex Easten]

Hello Alastair,

I've been quietly watching and am absolutely in awe of your build. This is gonna be quite the model when finished!

All the best,

Alex