Quote from: Rheged on June 16, 2023, 07:22:29 AMOne unexpected "Re-engine it"  is the real world landing craft  that made landfall on the Egyptian coast in 1941.  Full story here:-   https://www.royalmarineshistory.com/post/2017/12/27/sea-borne-escape-from-crete-in-a-damaged-landing-craft-royalmarines-commando

Blankets sewn together with bootlaces seems to meet the criteria for "re-engining it "

Similarly, USS R-14 might qualify as well. https://en.wikipedia.org/wiki/USS_R-14

I find that the easiest way to accurately scale the volume is by using the bore and stroke
dimensions multiplied by the scaling factor, those results are then used to calculate the
volume of a single cylinder. That number is multiplied by the number of cylinders to give
the total displacement.

Staying with the 351: bore 4"; stroke 3.5"; scaling factor 1.75 (35/20).

Bore: 4" X 1.75 = 7". Stroke: 3.5" X 1.75 = 6.125"

Formula for volume of a cylinder is the area of the bore (pi x r²) times the length of the
cylinder, the stroke in the case of a piston engine cylinder.

The radius of the bore is 3.5"; (pi X 3.5²) X 6.125" = ~ 235.72 in³ per cylinder,
235.72 X 8 = 1,885.76 in³ total displacement, approximately 31 litres.

Going the other way, from 1/35 to 1/20, gives a displacement of ~65 in³.

Quote from: jcf on June 16, 2023, 11:36:58 PMI find that the easiest way to accurately scale the volume is by using the bore and stroke
dimensions multiplied by the scaling factor, those results are then used to calculate the
volume of a single cylinder. That number is multiplied by the number of cylinders to give
the total displacement.

Staying with the 351: bore 4"; stroke 3.5"; scaling factor 1.75 (35/20).

Bore: 4" X 1.75 = 7". Stroke: 3.5" X 1.75 = 6.125"

Formula for volume of a cylinder is the area of the bore (pi x r²) times the length of the
cylinder, the stroke in the case of a piston engine cylinder.

The radius of the bore is 3.5"; (pi X 3.5²) X 6.125" = ~ 235.72 in³ per cylinder,
235.72 X 8 = 1,885.76 in³ total displacement, approximately 31 litres.

Going the other way, from 1/35 to 1/20, gives a displacement of ~65 in³.

Jon I'm 6'2 and I feel to short for how far above my head this is   
Guaranteed there will be chaps here which will understand this 😀

Quote from: zenrat on June 16, 2023, 05:23:35 AMYes.  It's the second version.  I have to cube stuff as its volume.

Thanks mate.

 

Yup. Should be around 5.35 times the original size/volume (=35/20³); "Doubling" the scale would mean that the volume increases by eight!

Quote from: jcf on June 16, 2023, 11:36:58 PMI find that the easiest way to accurately scale the volume is by using the bore and stroke
dimensions multiplied by the scaling factor, those results are then used to calculate the
volume of a single cylinder. That number is multiplied by the number of cylinders to give
the total displacement.

Staying with the 351: bore 4"; stroke 3.5"; scaling factor 1.75 (35/20).

Bore: 4" X 1.75 = 7". Stroke: 3.5" X 1.75 = 6.125"

Formula for volume of a cylinder is the area of the bore (pi x r²) times the length of the
cylinder, the stroke in the case of a piston engine cylinder.

The radius of the bore is 3.5"; (pi X 3.5²) X 6.125" = ~ 235.72 in³ per cylinder,
235.72 X 8 = 1,885.76 in³ total displacement.

Quote from: Old Wombat on June 16, 2023, 05:05:13 AMAlternately, you could divide the original capacity by 20³ & multiply the result by 35³, which equates to multiplying the original capacity by 5.36 (rounded to 2 decimal places).


In the original version above a 351ci V8 in 1/20 would become a 614.25ci V8 in 1/35

Whereas in the version immediately above that same 351ci V8 would become a 1,881.36ci V8 in 1/35


The difference is that the first equation reduces the capacity & then expands it in only one dimension, while the second equation reduces the capacity then expands it in three dimensions (& is, probably, far more accurate).

As both methods give the same result I think what Jon did was provide the proof for Womby's equation.

Anyhoo, if I use the sole 1/20 V8 in the stash I multiply by 5.36 to get the capacity in 1/35 scale. If I use one of the many 1/25 V8s I multiply by 2.74.

Quote from: PR19_Kit on June 14, 2023, 10:14:49 AMOr 'There ain't no substitute for cubic inches'............. 

"No replacement for displacement" 

I thought no math would be involved here!   Too early in the morning for math.  ha

Injection is nice but i'd rather be blown...

 

Quote from: zenrat on June 17, 2023, 05:44:52 AMInjection is nice but i'd rather be blown...

 

That has just got you referred to higher authorities and if you hear the thunder of hooves outside your residence or workplace I tried my best   

Quote from: zenrat on June 17, 2023, 05:44:52 AMInjection is nice but i'd rather be blown...

 

Reminds me of a cheeky 8 Sqn anti-Nimrod AEW zap prevalent during their Shackleton days

Quote from: kitbasher on June 17, 2023, 07:27:34 AM

Quote from: zenrat on June 17, 2023, 05:44:52 AMInjection is nice but i'd rather be blown...

 

Reminds me of a cheeky 8 Sqn anti-Nimrod AEW zap prevalent during their Shackleton days

I was thinking of exactly the same thing!!   But we'd better say no more or  we will rate another entry in The Book

ANOTHER entry? Chris will fill the ENTIRE book if you go on like that!!!! 

There's a library, all indexed and cross-referenced...

Quote from: zenrat on June 17, 2023, 05:44:52 AMInjection is nice but i'd rather be blown...

 

Does somebody need to get all technical here to save Fred from another entry in Chris's book ?
Even tho injection is nice and being blown is also very nice it's when you combine em ...ahh now that's pure harmony 

Quote from: Mossie on June 17, 2023, 08:55:28 AMThere's a library, all indexed and cross-referenced...

And it's still on paper and in Latin 

Quote from: NARSES2 on June 18, 2023, 12:15:11 AM

Quote from: Mossie on June 17, 2023, 08:55:28 AMThere's a library, all indexed and cross-referenced...

And it's still on paper and in Latin 

Don't tell me you can read Latin  Chris