
Builder Last Online: Feb 2011


Model Scale: 1/8
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Thanks: 0

Started: 02-22-10
Build Revisions: Never

Allison V-1710 V-12 "F" Type Aviation Engine
I just finished this model and thought that it may be of interest to someone else interested in this engine.
For quite awhile I have wanted to build a model of the Allison V-12 in its basic "F" type aviation configuration. There are several resin kits on the market in 1/72 and 1/48 scales but they are too small for me to work comfortably with and have some issues with accuracy. The only plastic kit I know of that was commercially offered in a larger scale is the early 1960's AMT 1/25 Custom-Competition kit #3007. However, it is not a model of the aviation version of the engine but is of the engine as it was modified for use in the early Unlimited Hydroplanes and possibly some drag cars of that period.
I was intrigued with the idea that maybe the AMT kit could be modified to create a fairly accurate model of the basic "F" type aviation engine. It had to be done with very limited modeling resources and as little added expense as possible.
After purchasing several kits on eBay I studied one and saw that overall the accuracy was good and that the basic central core of the engine - crankcase, cylinder blocks with heads, intake manifolds, etc. - was true to the aviation version. The changes needed were predominately at the front and rear, the gear case at the front being the biggest job. It required considerable reworking from an overdrive boat style unit where the driveshaft (boat prop shaft) exits the case below the crankshaft centerline to an underdrive aviation unit where the prop shaft exits the case above the crankshaft centerline and shaped as close as possible to the proper shape of the aviation case.
The supercharger housing and carburetor mount, carburetor, and starter also needed considerable reworking. The starter gearcase needed to be removed (not used on the "F" type engine); a generator, vacuum pump, exterior coolant tubes and manifolds, an air intake scoop, and a number of other small parts added. In the end I reworked to some degree almost every part in the kit in order to achieve the desired outcome and proper scale appearance. There is a photo of an aircraft museum display engine of the correct version, left front view, which can be used as reference when looking at the left front view photo of the model to get an idea of what I was trying to achieve with the front gear case.
Also, since I had a second kit I quickly rough assembled it (using mostly two-sided tape) in its original kit form and included a photo of it placed next to the finished model for comparison.
I did not fit exhaust manifolds to the model as can be seen. The manifolds in the AMT kit I believe are supposed to represent P-38 aircraft manifolds as commonly used on the early Unlimited Hydros which was what I wanted. However, they are not accurate to the originals. So far I have not been able to fabricate anything that I like so I left them off. The exhausts are an on-going project.
I made two engine stands since I was not sure which style I would prefer.
There is a photo of an engine as installed in a Curtiss P-40. Initially when I started to build the model I intended to build it representing an installation as pictured with the motor mount frame and the corresponding plumbing, coolers, etc. I found though as I got into it that working in this small scale with my limited resources it was difficult for me to reproduce those parts properly in scale that looked correct, at least to my eye. So I decided to just concentrate on getting the basic engine correct which was a sizable challenge in itself.
I think a larger scale of 1:12 would probably be about ideal for this type of model. It would offer a compromise between a comfortable size for accurate scale detailing and an affordable price for the basic kit.
There is also a photo of my small workstation. It is just a 14 x 11 cardboard box with lid for tools and a 17 x 11 green hobby mat to work on. Also a 2.5x Opti Visor and a 4x eye loupe. Since I don't have a dedicated workspace for hobby projects this arrangement allows me to have a mobile station that I can work out of and store away when finished each night.
Once this basic version is built there are a number of other versions of this engine as used in different aircraft that could be modeled. Four with two-stage supercharging and the turbocompound version. All in all a fun but challenging project.
Shel
I just finished this model and thought that it may be of interest to someone else interested in this engine.
For quite awhile I have wanted to build a model of the Allison V-12 in its basic "F" type aviation configuration. There are several resin kits on the market in 1/72 and 1/48 scales but they are too small for me to work comfortably with and have some issues with accuracy. The only plastic kit I know of that was commercially offered in a larger scale is the early 1960's AMT 1/25 Custom-Competition kit #3007. However, it is not a model of the aviation version of the engine but is of the engine as it was modified for use in the early Unlimited Hydroplanes and possibly some drag cars of that period.
I was intrigued with the idea that maybe the AMT kit could be modified to create a fairly accurate model of the basic "F" type aviation engine. It had to be done with very limited modeling resources and as little added expense as possible.
After purchasing several kits on eBay I studied one and saw that overall the accuracy was good and that the basic central core of the engine - crankcase, cylinder blocks with heads, intake manifolds, etc. - was true to the aviation version. The changes needed were predominately at the front and rear, the gear case at the front being the biggest job. It required considerable reworking from an overdrive boat style unit where the driveshaft (boat prop shaft) exits the case below the crankshaft centerline to an underdrive aviation unit where the prop shaft exits the case above the crankshaft centerline and shaped as close as possible to the proper shape of the aviation case.
The supercharger housing and carburetor mount, carburetor, and starter also needed considerable reworking. The starter gearcase needed to be removed (not used on the "F" type engine); a generator, vacuum pump, exterior coolant tubes and manifolds, an air intake scoop, and a number of other small parts added. In the end I reworked to some degree almost every part in the kit in order to achieve the desired outcome and proper scale appearance. There is a photo of an aircraft museum display engine of the correct version, left front view, which can be used as reference when looking at the left front view photo of the model to get an idea of what I was trying to achieve with the front gear case.
Also, since I had a second kit I quickly rough assembled it (using mostly two-sided tape) in its original kit form and included a photo of it placed next to the finished model for comparison.
I did not fit exhaust manifolds to the model as can be seen. The manifolds in the AMT kit I believe are supposed to represent P-38 aircraft manifolds as commonly used on the early Unlimited Hydros which was what I wanted. However, they are not accurate to the originals. So far I have not been able to fabricate anything that I like so I left them off. The exhausts are an on-going project.
I made two engine stands since I was not sure which style I would prefer.
There is a photo of an engine as installed in a Curtiss P-40. Initially when I started to build the model I intended to build it representing an installation as pictured with the motor mount frame and the corresponding plumbing, coolers, etc. I found though as I got into it that working in this small scale with my limited resources it was difficult for me to reproduce those parts properly in scale that looked correct, at least to my eye. So I decided to just concentrate on getting the basic engine correct which was a sizable challenge in itself.
I think a larger scale of 1:12 would probably be about ideal for this type of model. It would offer a compromise between a comfortable size for accurate scale detailing and an affordable price for the basic kit.
There is also a photo of my small workstation. It is just a 14 x 11 cardboard box with lid for tools and a 17 x 11 green hobby mat to work on. Also a 2.5x Opti Visor and a 4x eye loupe. Since I don't have a dedicated workspace for hobby projects this arrangement allows me to have a mobile station that I can work out of and store away when finished each night.
Once this basic version is built there are a number of other versions of this engine as used in different aircraft that could be modeled. Four with two-stage supercharging and the turbocompound version. All in all a fun but challenging project.
Shel
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