Suggestions for building an exhaust manifold for a Wasp radial?

[billn53]

I'm currently building the venerable Airfix Ford Tri-motor, an will be replacing the kit's lame engines with highly-detailed resin kit from Small Stuff (beautiful!).

 

 

I will need to scratch up some exhaust manifolds, and could use some ideas on how to best approach that task. For example, should I use stretched sprue? Brass rod? Solder? etc.

 

For reference, here are some pics of the actual aircraft's exhausts:

 

 

 

 

 

Thanks in advance!

 

-Bill

 

Edited December 20, 2018 by billn53

[dnl42]

Are you building a model of that specific aircraft in its current modern configuration or the aircraft in the late '20s or early '30s? If the latter, do check the correctness of that exhaust manifold. A quick perusal of contemporaneous photos at Wikimedia Commons show several variants, including both your Small Things version as well as the modern photos. The modern version may well be correct, but I personally never trust photos of modern aircraft until I've seen the specific feature in a contemporaneous photo.

 

FWIW, I've got a similar future task to make a proper N2S-3 from the Revell's 1/48 PT-17 kit. While the engine per se that I bought from Engines and Things is fine, the exhaust manifold they provide is a simple ring--far from what it should look like. I was thinking of making the skeleton form from the resin ring and Albion tubing and then bulking it up with Milliput Superfine White putty.

[DMC]

Hi Bill,

 

I’ve had a couple of the Small Stuff rotaries and they are indeed small.  Since you have three exhaust set-ups to make probably the easiest way to go about would be to make a master and cast three out of resin.  Not all that easy I realise but it would save you the bother of piecing together a dozen or more minute pieces of styrene rod and doing it three times.  

 

If if you choose to do each one separately you might try wrapping the appropriate size rod around a dowel, pencil size?, and setting it with boiling water.  This would give you the necessary curves you’ll need to piece the manifolds together.  

 

Either method would require a jig a jig of some sort.  

 

Can’t think of any other way to go about it if I had to do it.  Perhaps a more experienced modeller might be able to suggest another way. 

 

Good luck

 

Dennis

 

[billn53]

7 hours ago, dnl42 said:

Are you building a model of that specific aircraft in its current modern configuration or the aircraft in the late '20s or early '30s? If the latter, do check the correctness of that exhaust manifold. A quick perusal of contemporaneous photos at Wikimedia Commons show several variants, including both your Small Things version as well as the modern photos. The modern version may well be correct, but I personally never trust photos of modern aircraft until I've seen the specific feature in a contemporaneous photo.

 

FWIW, I've got a similar future task to make a proper N2S-3 from the Revell's 1/48 PT-17 kit. While the engine per se that I bought from Engines and Things is fine, the exhaust manifold they provide is a simple ring--far from what it should look like. I was thinking of making the skeleton form from the resin ring and Albion tubing and then bulking it up with Milliput Superfine White putty.

 

I'm modeling a "generic" Tri-motor circa 1930, not any specific aircraft, so I have some flexibility in how I so the exhaust. Your idea of a center ring & tubing, bulked up with Milliput or similar, sounds promising. Thanks for the suggestion. 

Bill

[billn53]

3 hours ago, DMC said:

Hi Bill,

 

I’ve had a couple of the Small Stuff rotaries and they are indeed small.  Since you have three exhaust set-ups to make probably the easiest way to go about would be to make a master and cast three out of resin.  Not all that easy I realise but it would save you the bother of piecing together a dozen or more minute pieces of styrene rod and doing it three times.  

 

If if you choose to do each one separately you might try wrapping the appropriate size rod around a dowel, pencil size?, and setting it with boiling water.  This would give you the necessary curves you’ll need to piece the manifolds together.  

 

Either method would require a jig a jig of some sort.  

 

Can’t think of any other way to go about it if I had to do it.  Perhaps a more experienced modeller might be able to suggest another way. 

 

Good luck

 

Dennis

 

Thanks, Dennis. I suspect the idea of casting from a single mold won't be feasible. My resin casting skills probably aren't up to the job. Also, unless I'm wrong,  think each other engine's exhaust are different -- the manifolds for the two outer engines are mirror images of each other, and the engine on the nose collects exhaust and directs it to a centerline outlet. 

 

I'll try your suggestion for creating a styrene ring... I much prefer using styrene over brass rod simply because it's easier to work with. 

 

Your idea of a jig is a good one, now to figure out how to make one. Perhaps I can assemble the cylinders to the center hub, and use that to cast just the backside of the engine for my jig?

 

Thanks again!

[Max Headroom]

Interesting project and I hope you do a WIP as you go.

 

I’m all for keeping something as simple as possible, so my suggestion would be to use plastic insulated wire of a suitable diameter for the main ring. Bend it to the right shape - use a dowel to get the right circumference if need be. Individual exhausts could be superglued between the cylinders and collector ring. Hollow plastic tube could be employed for the exhaust. Joins could be simulated with thinned PVA glue?

 

Just a thought as this isn’t something I’ve actually done yet, but I have a stalled Tamiya Beaufighter mainly because I need to install plumbing and this is the method that keeps suggesting itself to me.

 

HTH

 

Trevor

[billn53]

2 minutes ago, Max Headroom said:

Interesting project and I hope you do a WIP as you go.

 

I’m all for keeping something as simple as possible, so my suggestion would be to use plastic insulated wire of a suitable diameter for the main ring. Bend it to the right shape - use a dowel to get the right circumference if need be. Individual exhausts could be superglued between the cylinders and collector ring. Hollow plastic tube could be employed for the exhaust. Joins could be simulated with thinned PVA glue?

 

Just a thought as this isn’t something I’ve actually done yet, but I have a stalled Tamiya Beaufighter mainly because I need to install plumbing and this is the method that keeps suggesting itself to me.

 

HTH

 

Trevor

Hi Trevor!

I'm all in favor of simple 🙂  thanks for the suggestion, I'll give it a try. 

 

WIP is well underway, check it out here:

 

 

Bill

[dnl42]

2 hours ago, billn53 said:

I'm modeling a "generic" Tri-motor circa 1930, not any specific aircraft, so I have some flexibility in how I so the exhaust. Your idea of a center ring & tubing, bulked up with Milliput or similar, sounds promising. Thanks for the suggestion. 

Bill

Given the task, why not use the engines as-as? Take a look at the Wikimedia Commons site I cited above. I do believe you would be correct using that exhaust arrangement.

[dogsbody]

Some Fords were powered by Wright Whirlwinds with a front-mounted exhaust collector.

 

http://www.primeportal.net/hangar/dave_kitchel/1927_ford_trimotor/

 

https://www.masterfile.com/image/en/846-02795935

 

 

 

Chris

[billn53]

I want to thank everybody for your most helpful suggestions, and give you an update on my effort to scratchbuild exhaust manifolds for my Ford Tri-motor:

 

 

 

-Bill