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1/12 Tamiya Honda F1 RA273


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Now, I'm expecting someone far brighter and intelligent than myself to instantly solve this problem as I'm fully aware there are several members of this community whose modelling skills are way above my own and are rather jolly good at this sort of thing. 

I've been working on this model for several years (as usual!) and was never satisfied that Tamiya merely truncated the exhaust system with (uneven) straight down pipes simply 'resting' on the top of the engine block. I've pored over scores of online reference images and only in the last few months realised that the pipes actually connect to the inside of the walls of the block. However, trying to work out the bend of each pipe, in more than one plane, is far beyond the capacity of my tiny addled 'one cell at a time' brain (mind you, it appears that the chaps at Tamiya, in those early days, also had a headache with this one, as far as I can see their pipe profiles are not exactly true to the real thing). There's got to be an easier way than how I'm tackling it.

So, come on you wonderful engineers, give us a glimpse of those scale drawings you've already drawn up on this subject...

 

If I ever manage to solve the puzzle myself I'll be sure to bequeath my working progress to this wonderful institution - damn, better start making some notes.

 

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Hi Tony,

 

You don't seem to have much luck with exhausts!😀

 

I agree, IMHO the lack of any coherent exhaust joint to the cylinder heads is the worst part of this kit. Although I believe the very first issue of this kit (and Tamiya's first F1 in 1/12) included wheels that were so wrong they retooled them.

 

It took me years to find a picture of the centre vee of this engine with the exhausts removed.

Seems like you are doing it the way I would, I assume you are using solder wire for the exhausts? You just have to take it one header at a time and using plenty of blutack to hold the finished parts in the right position, move on to the next and prepare for lots of reworking!

Your jig to replicate the exhaust ports off the engine is a good idea.

Short of CAD drawing and 3D printing the exhausts, I know of no other simple way to do this!

We need to commission @nick to print some for us - I would buy a set........

 

Malc.

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8 minutes ago, Malc2 said:

Hi Tony,

 

You don't seem to have much luck with exhausts!😀

 

I agree, IMHO the lack of any coherent exhaust joint to the cylinder heads is the worst part of this kit. Although I believe the very first issue of this kit (and Tamiya's first F1 in 1/12) included wheels that were so wrong they retooled them.

 

It took me years to find a picture of the centre vee of this engine with the exhausts removed.

Seems like you are doing it the way I would, I assume you are using solder wire for the exhausts? You just have to take it one header at a time and using plenty of blutack to hold the finished parts in the right position, move on to the next and prepare for lots of reworking!

Your jig to replicate the exhaust ports off the engine is a good idea.

Short of CAD drawing and 3D printing the exhausts, I know of no other simple way to do this!

We need to commission @nick to print some for us - I would buy a set........

 

Malc.

Brilliant response as usual, Malc, you always make me feel better about my progress.

 

Yes, exhausts and me...    well, they just have to be right, don't they? I'm actually using 2.5mm soft aluminium wire from www.wires.co.uk, couldn't find solder wire that thick. It's quite maleable but also marks easily with pliers or any other tool so bending is not as easy as it seems. I have only this reference for the centre 'vee':

 

p?i=891fbd3066eca6a2b7a4e940e113d1d7

 

 

Does @nick produce custom 3D parts?

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Hi Tony,

 

This is the only other pic I could find:-

http://ra273motor2.jpg

2.5mm solder wire here:- https://www.ebay.co.uk/itm/393418510430?hash=item5b9992105e:g:i8QAAOSw~nFf2Lmq

I agree its hard not to add flats to the wire with the pliers.

How about copper wire as an alternative?

The only other technique I have seen is to roll sausages of milliput, drape them to the shape you want and let it set, but there is no adjustability afterwards and you would still probably get flat spots from handling, but I want to have a go doing this at some point. What appeals to me about this is that you can produce the exact diameter you want by having 2 slats of the required thickness placed 6in apart to control the thickess of the sausage by using a piece of plastic across the slats to roll the sausage.

 

I was kinda joking about @nick, but half hoping that he would jump in!

I think he is fully busy with his 1/8 F40 engine, but it would not hurt to ask him?

 

Malc.

Edited by Malc2
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2 hours ago, Malc2 said:

Hi Nick,

 

This is the only other pic I could find:-

http://ra273motor2.jpg

2.5mm solder wire here:- https://www.ebay.co.uk/itm/393418510430?hash=item5b9992105e:g:i8QAAOSw~nFf2Lmq

I agree its hard not to add flats to the wire with the pliers.

How about copper wire as an alternative?

The only other technique I have seen is to roll sausages of milliput, drape them to the shape you want and let it set, but there is no adjustability afterwards and you would still probably get flat spots from handling, but I want to have a go doing this at some point. What appeals to me about this is that you can produce the exact diameter you want by having 2 slats of the required thickness placed 6in apart to control the thickess of the sausage by using a piece of plastic across the slats to roll the sausage.

 

I was kinda joking about @nick, but half hoping that he would jump in!

I think he is fully busy with his 1/8 F40 engine, but it would not hurt to ask him?

 

Malc.


Hi all, only just seen this. Looks easy enough. I’m guessing the exhaust flanges are all the same? And what in what looks like 4 banks of 3 at a constant pitch? They look like they are equal length pipes too?

 

just need a few measurements and I’ll knock something up - have you got a digital caliper?

 

They look like they are equal length pipes too?

 

OK looked properly now, so I think you’re saying Tamiya didn’t model anything inside the vee? If so, you actually just need 4 flat plates with 3 flanges, studs, nuts and curly pipes each going to a collector and tailpipe. That’s easier so I just need the height and width of each plate, the distance between the inside faces of the vee, and the distance and height offset of where the collectors start and end. And also where the tailpipes drop down and end if you want those making too. 

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1 hour ago, Malc2 said:

Hi Nick,

 

This is the only other pic I could find:-

http://ra273motor2.jpg

2.5mm solder wire here:- https://www.ebay.co.uk/itm/393418510430?hash=item5b9992105e:g:i8QAAOSw~nFf2Lmq

I agree its hard not to add flats to the wire with the pliers.

How about copper wire as an alternative?

The only other technique I have seen is to roll sausages of milliput, drape them to the shape you want and let it set, but there is no adjustability afterwards and you would still probably get flat spots from handling, but I want to have a go doing this at some point. What appeals to me about this is that you can produce the exact diameter you want by having 2 slats of the required thickness placed 6in apart to control the thickess of the sausage by using a piece of plastic across the slats to roll the sausage.

 

I was kinda joking about @nick, but half hoping that he would jump in!

I think he is fully busy with his 1/8 F40 engine, but it would not hurt to ask him?

 

Malc.

Oh I've been through any number of wires Malc. I have some copper armature for posable figures but it's even harder to bend. I've ordered some of the 2.5mm solder as per your suggestion.

Yes, I checked out @nick, wonderful stuff he's producing.

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6 hours ago, nick said:


Hi all, only just seen this. Looks easy enough. I’m guessing the exhaust flanges are all the same? And what in what looks like 4 banks of 3 at a constant pitch? They look like they are equal length pipes too?

 

just need a few measurements and I’ll knock something up - have you got a digital caliper?

 

They look like they are equal length pipes too?

 

OK looked properly now, so I think you’re saying Tamiya didn’t model anything inside the vee? If so, you actually just need 4 flat plates with 3 flanges, studs, nuts and curly pipes each going to a collector and tailpipe. That’s easier so I just need the height and width of each plate, the distance between the inside faces of the vee, and the distance and height offset of where the collectors start and end. And also where the tailpipes drop down and end if you want those making too. 

Hello Nick.

Crikey, you make it sound so simple. Ok, I'll try and get those measurements to you - I do have a digital caliper. It would be preferable to have the pipes come from the 'collector' (if that's the right term) of each 4 end pipes. Bear with me.

Seriously, are you ok to do this? Do you know what sort of cost we are talking about.

 

Many thanks to both you and Malc for your interest and responses.

 

I'm coming to N Wales tomorrow, visiting a friend in Conway. I used to live on Anglesey.

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Fantastic! Thanks Nick.

If I can help with info/pictures/dimentions etc let me know.

Looks like all the head port flanges are the same, just that the front three are oriented 90deg differently from the rear three on each bank.

 

Malc.

Edited by Malc2
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Hi Tony,

 

Have you found this link https://forums.autosport.com/topic/208785-advantages-of-dual-or-triple-exhaust-on-a-bank-of-six-cylinders/


It suggests a firing sequence for the engine and a grouping for the headers. Hopefully confirming what you know. The most difficult headers seem to be 5 and 6 on each bank (numbered from the front), does that line up with your understanding?

 

Nick

(yes - yet another Nick - normally we are not this numerous!)

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  • 3 weeks later...
On 30/07/2021 at 16:40, NickD said:

Hi Tony,

 

Have you found this link https://forums.autosport.com/topic/208785-advantages-of-dual-or-triple-exhaust-on-a-bank-of-six-cylinders/


It suggests a firing sequence for the engine and a grouping for the headers. Hopefully confirming what you know. The most difficult headers seem to be 5 and 6 on each bank (numbered from the front), does that line up with your understanding?

 

Nick

(yes - yet another Nick - normally we are not this numerous!)

 

 

Hello Nick (another Nick) 🙂

 

I'm so sorry, you must think me very rude or ignorant. I have only just seen your response. Thank you very much, that's very informative, if actually way above what my tiny little brain can accomodate.

 

Tony

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Hi Tony,

 

No worries, I know how it is, I did exactly the same on a thread I started recently - oops.

As for the pipes, they do seem very complicated. None of the pictures seem to show the pipe from 6 (the one nearest the exhaust). At least if you can route it no one will be able to say it is wrong!

 

Nick

 

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