AlexM

As always, most impressive work, Alex! Nice to see her on her feet!
 
Regards,
 
Jason

Hello there, again little progress.
One thing that causes headache is the main landing gear, which is angeled forward in a scary way, while the whole model is rather heavy, not least because of the counterweights to prevent the notorious tail-sitting. The green one, which is printed as one single part, is in no way strong enough, will bend and propably breake. I'm thinking about metal casting by a goldsmith, but I guess this wouldn't be cheap. So right now, I'll try a multi-piece landing gear with 2mm steel rod enforcement. The upper part of the fork now consists of two halves which cover a bent steel rod.  There are still weak spots, but maybe it works. Whish me luck 
 

 

 

 
Cheers
Alex

Thanks, Mark!
 
I know what you mean. I printed the parts with a resin that is advertised to be very strong. After all parts were glued together, I put some more liquid resin at the seams and put it under UV light to cure. Now, It's more or less one single resin part with steel-rods within. I'll watch it for some time and hope that is stays stable, especially at the weak point you mentioned.
 
One nice thing is that the balance can now be checked to prevent tail sitting. Until now, the necessary counterweight at the area forward of the main landing gear has only been roughly calculated. Now, with most weight-relevant parts provisionally attached, it already stands like it should. And the resin engines and the forward landing gear isn't attached yet, so I think at least regarding that aspect I'm safe. The weight on the nose landing gear will be minimal, so a fully printed nose gear without metal-rod-enforcement should be fully sufficient.
 

 
Cheers
Alex

Thanks guys!
 
 
I think you are right, if everything else fails, a metal landing gear would be a reasonable investition. Meanwhile, I provisionally pluged the steel-rod-enforced legs and the small support struts into the the designated openings in the wheel wells for a first test. And right now, it looks promising. Not bending visible
 

 

 
I'll leave it like this for a while to see if it stays stable.
 
Cheers
ALex

Hello there, again little progress.
One thing that causes headache is the main landing gear, which is angeled forward in a scary way, while the whole model is rather heavy, not least because of the counterweights to prevent the notorious tail-sitting. The green one, which is printed as one single part, is in no way strong enough, will bend and propably breake. I'm thinking about metal casting by a goldsmith, but I guess this wouldn't be cheap. So right now, I'll try a multi-piece landing gear with 2mm steel rod enforcement. The upper part of the fork now consists of two halves which cover a bent steel rod.  There are still weak spots, but maybe it works. Whish me luck 
 

 

 

 
Cheers
Alex

Thanks, Mark!
 
I know what you mean. I printed the parts with a resin that is advertised to be very strong. After all parts were glued together, I put some more liquid resin at the seams and put it under UV light to cure. Now, It's more or less one single resin part with steel-rods within. I'll watch it for some time and hope that is stays stable, especially at the weak point you mentioned.
 
One nice thing is that the balance can now be checked to prevent tail sitting. Until now, the necessary counterweight at the area forward of the main landing gear has only been roughly calculated. Now, with most weight-relevant parts provisionally attached, it already stands like it should. And the resin engines and the forward landing gear isn't attached yet, so I think at least regarding that aspect I'm safe. The weight on the nose landing gear will be minimal, so a fully printed nose gear without metal-rod-enforcement should be fully sufficient.
 

 
Cheers
Alex

Hello there, again little progress.
One thing that causes headache is the main landing gear, which is angeled forward in a scary way, while the whole model is rather heavy, not least because of the counterweights to prevent the notorious tail-sitting. The green one, which is printed as one single part, is in no way strong enough, will bend and propably breake. I'm thinking about metal casting by a goldsmith, but I guess this wouldn't be cheap. So right now, I'll try a multi-piece landing gear with 2mm steel rod enforcement. The upper part of the fork now consists of two halves which cover a bent steel rod.  There are still weak spots, but maybe it works. Whish me luck 
 

 

 

 
Cheers
Alex

Thanks, Mark!
 
I know what you mean. I printed the parts with a resin that is advertised to be very strong. After all parts were glued together, I put some more liquid resin at the seams and put it under UV light to cure. Now, It's more or less one single resin part with steel-rods within. I'll watch it for some time and hope that is stays stable, especially at the weak point you mentioned.
 
One nice thing is that the balance can now be checked to prevent tail sitting. Until now, the necessary counterweight at the area forward of the main landing gear has only been roughly calculated. Now, with most weight-relevant parts provisionally attached, it already stands like it should. And the resin engines and the forward landing gear isn't attached yet, so I think at least regarding that aspect I'm safe. The weight on the nose landing gear will be minimal, so a fully printed nose gear without metal-rod-enforcement should be fully sufficient.
 

 
Cheers
Alex

Hello there, again little progress.
One thing that causes headache is the main landing gear, which is angeled forward in a scary way, while the whole model is rather heavy, not least because of the counterweights to prevent the notorious tail-sitting. The green one, which is printed as one single part, is in no way strong enough, will bend and propably breake. I'm thinking about metal casting by a goldsmith, but I guess this wouldn't be cheap. So right now, I'll try a multi-piece landing gear with 2mm steel rod enforcement. The upper part of the fork now consists of two halves which cover a bent steel rod.  There are still weak spots, but maybe it works. Whish me luck 
 

 

 

 
Cheers
Alex

Thanks, Mark!
 
I know what you mean. I printed the parts with a resin that is advertised to be very strong. After all parts were glued together, I put some more liquid resin at the seams and put it under UV light to cure. Now, It's more or less one single resin part with steel-rods within. I'll watch it for some time and hope that is stays stable, especially at the weak point you mentioned.
 
One nice thing is that the balance can now be checked to prevent tail sitting. Until now, the necessary counterweight at the area forward of the main landing gear has only been roughly calculated. Now, with most weight-relevant parts provisionally attached, it already stands like it should. And the resin engines and the forward landing gear isn't attached yet, so I think at least regarding that aspect I'm safe. The weight on the nose landing gear will be minimal, so a fully printed nose gear without metal-rod-enforcement should be fully sufficient.
 

 
Cheers
Alex

Thanks guys!
 
 
I think you are right, if everything else fails, a metal landing gear would be a reasonable investition. Meanwhile, I provisionally pluged the steel-rod-enforced legs and the small support struts into the the designated openings in the wheel wells for a first test. And right now, it looks promising. Not bending visible
 

 

 
I'll leave it like this for a while to see if it stays stable.
 
Cheers
ALex

When I look at the breakdown of your parts, there is a weak spot where the two steel rods do not meet.  An alternative is to make your core our of brass rods that can be soldered to form a continuous strong core.

That's a beauty.
 
Sincerely,
Mark

The Special Hobby Yak-3 spinner and prop from Michael arrived yesterday, so I was able to finalize the 3D model of the last piece with the diameter of the spinner. I chose to print that piece because it was actually a very tough piece to build by hand, but Ironically, was extremely simple in the 3D software. And why print one, when you can print 5!! That way I can screw up 4 of them.

 
 
After some slight modifications to the spinner to match the reference photo (I made more pointy and drilled the hole), time for a test install on the front piece:

 
 
Looks good so far to my eye, so now a test fit altogether. I tried to replicate the angle of the photo:

 
 
Nose is looking good, but I immediately noticed that the hump above the exhaust port is way too big!! I also need to cut that little hole just below the exhaust.

So, on to re-shape the humps to a more realistic size.
 
Tim

Trying to get back into actually building things again - have picked up on a Tempest I started a while back:
 

 

 

 

 

 
Really enjoying this one - some very sharp/neat moulding - but parts still need test fitting and careful fettling at each stage.
 
More shortly...
 
Have fun.
 
Iain

Thanks guys!
 
 
I think you are right, if everything else fails, a metal landing gear would be a reasonable investition. Meanwhile, I provisionally pluged the steel-rod-enforced legs and the small support struts into the the designated openings in the wheel wells for a first test. And right now, it looks promising. Not bending visible
 

 

 
I'll leave it like this for a while to see if it stays stable.
 
Cheers
ALex

Hello there, again little progress.
One thing that causes headache is the main landing gear, which is angeled forward in a scary way, while the whole model is rather heavy, not least because of the counterweights to prevent the notorious tail-sitting. The green one, which is printed as one single part, is in no way strong enough, will bend and propably breake. I'm thinking about metal casting by a goldsmith, but I guess this wouldn't be cheap. So right now, I'll try a multi-piece landing gear with 2mm steel rod enforcement. The upper part of the fork now consists of two halves which cover a bent steel rod.  There are still weak spots, but maybe it works. Whish me luck 
 

 

 

 
Cheers
Alex

Thanks guys!
 
 
I think you are right, if everything else fails, a metal landing gear would be a reasonable investition. Meanwhile, I provisionally pluged the steel-rod-enforced legs and the small support struts into the the designated openings in the wheel wells for a first test. And right now, it looks promising. Not bending visible
 

 

 
I'll leave it like this for a while to see if it stays stable.
 
Cheers
ALex

Thanks guys!
 
 
I think you are right, if everything else fails, a metal landing gear would be a reasonable investition. Meanwhile, I provisionally pluged the steel-rod-enforced legs and the small support struts into the the designated openings in the wheel wells for a first test. And right now, it looks promising. Not bending visible
 

 

 
I'll leave it like this for a while to see if it stays stable.
 
Cheers
ALex

Based on what I can see, I think that the greatest danger to the collapse of the landing gear will be located here, either at the top end next to the horizontal part of the steel rod, or (in my view less likely but still possible) at the bottom of the hole where the vertical rod will be connected.
 
The first failure will be the result of shear forces in the plaastic next to the rod, while the second failure type would be a result of poor bonding between veritcal steel rod and plastic, allowing the steel rod to slide into the plastic.
 
If (as I think you are doing ) the same idea is used in the bottom part of the 'u-shaped' part of your landing gear (i.e. a horizontal rod through the axis of the wheel) an this sits to the side of the vertical rod you again create a weak spot susceptible to shear forces.
 
Then again, as long as your shear forces are well below the Young's modules for the plastic you use you will be all right.

Considering the amount of time and money you've invested in this model, getting the undercarriage cast in brass  would be worthwhile I think.  Alistair from Aerocraft Models gets his undercarriage cat in brass - maybe worth a chat with him.
 

Good luck.  Machine the core.  Details are add-ons.
 
Sincerely,
Mark

Amazing progress. I wish you a lot of strength. I will watch.

Little Marauder update:
Over the weekend, I made some more clear vacuformed parts for the nose, turret and tail. The nose must be redone as I wasn't careful enough when romoving from the mould, so what you see is just for a quick demonstration:
 

 

 

 

 

 

 
It all still need some clean-up, but overall the plan seems to work out.
 
I enlarged the opening in the fuselage for the turret since I have the impression the turret is too small on the plan from the Warpaint book. Somewhere I read that the turret diameter is 41 inch.
 
Talking about the turret, the obvious question arises: what color for the turret? On some pictures they are some kind of interior green:
https://c1.staticflickr.com/5/4908/44189918460_86a363267c.jpg
That's the turret from Flak Bait:
https://thumbs-media.smithsonianmag.com/filer/86/6f/866f22ba-be2d-49fa-b846-9b78c6983c8a/4.jpg__1072x0_q85_upscale.jpg
Here, the turret seems to be metal/aluminium:
https://c2.staticflickr.com/6/5099/5521447033_6b3d731ef3_b.jpg
Here not:
https://i.ytimg.com/vi/HG_DQC1deB0/maxresdefault.jpg
Here on the production line, they are black/dark grey:
http://320thbg.org/martin_marauder/domes_destruction.jpg
 
At the moment, I tend to black/dark grey for my model, but any additional information would be welcome.
 
Cheers
Alex.
 
 

Hi Jason,
so true, those Soviet twins in "our" scale would be great, as well as an Il-4.
 
 
Thanks a lot!
 
Christmas holiday means modeling time 
Sooner or later, the day will come when the fuselage halves get glued together. Before that, most interiors have to be done. One big challenge is the Martin 250 CE turret. I collected all photos I found, as well some handbooks and manuals. But I couldn't find one single scale drawing. The circumstance, that there were apparently variours versions of the turret with detail differneces doesn't make things easier. So, the end-result will contain some artistic licence and simplification. That's the current status of the 3d-model:
 

 

 
 
I also took a closer look on the rear gunner station and realized that the end opening is way to narrow, so the rear section had to be redone. To make it fit to the rest of the fuselage, some comprises were still necassary. It's far from perfect, but hopefully better than the old part:
 

 

 
The silver one is the old part
 

 

 

 

 
Cheers
Alex