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The Quest for Speed : 1/32 Travel Air Mystery Ship with some hi-tech


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Hubert - I have a few images I took of the replica at Oshkosh back in 1991 - I didn't take them with an eye for modeling back then, but they might be useful. If you want copies, just PM your email and I'll send them over.

 

Cheers!

 

John.

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That sounds great ;)

  

Cool project Hubert! Will definitely follow along

  

This is gonna be great! Can't wait to see more!

  

Hubert - I have a few images I took of the replica at Oshkosh back in 1991 - I didn't take them with an eye for modeling back then, but they might be useful. If you want copies, just PM your email and I'll send them over.

 

Cheers!

 

John.

draw

 

Thank you my friends :) !

 

Loïc, good to see you back. I hope you feel in a better mood.

Brian, glad to have you along ;)

Thanks Tom. I hope i can post some progress on the engine before I leave for vacations this sunday ...

John, PM sent. Many thanks for the offer .

 

Regarding the engine, I am not happy with the look of the cylinder heads by Williams. I have done some drawings on the Silhouette, and will try an experiment in the line of the Menasco cylinder I did for my ST-M. Tomorrow is busy as well, but hopefully I will have something to show by Saturday.

 

Cheers for now.

 

Hubert

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Guest Clunkmeister

Hubert, if an airplane could ever convince me to start welding, cutting wood, and sewing up a new reproduction, the Mystery Ship is the one.

 

I truly LOVE this airplane and like I said before, in my mind, it is one of the most beautiful airplanes ever designed, by any person, in any nation, at any time.

Some airplanes, make your heart beat faster, this airplane makes my heart RACE.

 

Thank you so, so much for building this airplane.

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Thank you for the pics, Iain. They are indeed beautiful :)

 

Ernie, I share your love of this airplane. I can very well see why it has an almost iconic status in the US, even though, advanced as it was, it was still not as fast or sophisticated as the contemporary European Schneider racers.

 

FWIW, as I am in the engine thing right now, the engine on the replica is a Lycoming R-675. Almost the same dimensions (but not the displacement) as the Wright J6-9. This was the engine of the Stearman PT-17. I have not checked whether Silver Wings sell it individually, but if yes, it could be used by those wanting to model the replica.

 

Hubert

Edited by MostlyRacers
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A small update on the work on the engine. Tomorrow, we are leaving for a 2 1/2 weeks vacation in Poland. So this will be the last update for at least 3 weeks.

 

As you can see from the pics above, the engine in the kit is inspired by the Williams P&W Wasp engine, when the Mystery Ship Wright J6-9 was fairly different.

 

First is the engine block. The Wright J6-9 had a very distinctive conical shape for the reduction gear crankcase, and the pushrods were behind the cylinders.

 

I turned a new block of 16 mm dia out of a 20 mm plastic rod found in a DYI store. My lathe is a small Unimat 1 that I have tried over time to improve by making it more rigid, but it is still far from ideal. It is also not possible to turn conical shapes on it by moving the cutting tool diagonally. Cones have to be turned free-hand, and smoothed with files, and I managed a passable result in the end.

 

The reduction-gear crankcase was bolted to the engine-block. I was too lazy (and not confident enough in its precision) to use the dividing tool on my Unimat. So the distance between the bolts was calculated, and a divider used to report the distance between the bolts, whose places were then drilled one by one with an 0.5 mm drill. I have used Scale Hardware simulated hex bolts, of 0.85 mm size. They are objectively a bit too big, but the result is nevertheless convincing enough. The propeller plate "bolts" were simulated using an 0.5 mm Punch n' Die, on a 0.5 mm thick sheet of styrene.

 

DSC00678_zpsmxnew2uy.jpg

 

The cylinder bases are 5.5 mm discs cut in a 0.5 mm plastic sheet with a punch and glued on the original cylindrical engine-block. They were subsequently reduced in height by sanding them down. The holes for the push-rods have been drilled as well.

 

DSC00679%201_zpskxihcpgv.jpg

 

Now is the time to move to the cylinders. One of my references is Edward H. Phillips "Mystery Ship" book published in 1999 by Flying books. On page 11 are two interesting pics of the first trials of the Msytery Ship sans the NACA cowling. Even though the pics are grained, an inspection with a magnifier shows that the cylinders did not have a side exhaust port as on the pic in a previous post, but on the top of the cylinder heads.

 

DSC00688_zpsq22505vv.jpg

DSC00689_zpsilopvzhk.jpg

 

So I decided to modify the cylinders from the Williams Bros J6-9 engine, cutting off the side exhaust port, drilling the hole for the plugs, and a new hole on top of the cylinder head for later fixing of the exhaust tubes.

 

DSC00677_zps2jvil7cc.jpg

 

However, as you can see on the pic, the definition of the cylinder heads is far from convincing. Time for a new trial, as the shape of the head was fairly simple, especially compared to later radial engines.

I have a Silhouette cutter. I have drawn the shapes of the cylinder heads and exhaust rocket-arm extensions on the software that comes with it, alternating wider and smaller diameter ellipses or circles. The idea is to stack them to represent the finned head. I have also drawn a 2mm dia central hole to allow to use a plastic rod as a centering guide for stacking the layers.

 

The Silhouette is a nice and fairly precise tool, and I gave it a go at cutting a thin (5 thou, i.e. 0,13 mm) plastic sheet, the only one in my supplies being a transparent one. I should have chosen to option for two cuts, rather than trying to get one cut of the correct depth. Th tip of the Silhouette blade broke-off fairly rapidly, unfortunately, leaving the sheet scribed but not cut ...

 

DSC00680_zpsvckrmwkk.jpg

 

 

And of course, I had no spare blade :BANGHEAD2:

 

Another trial with the broken blade was not too convincing. I have ordered a new set of blades, but they will arrive during my vacations.

 

DSC00687_zpsevj0z6uk.jpg

 

I nevertheless had enough good parts to do some trials. Enough to find out that alternating one large diameter part with a small dia one does not produce the best visual results. Having two small dia pieces between the large ones is more convincing, even if less in-line with the prototype ... On the left is a trial with one small dia interval, and on the right two small dia intervals. Sorry, the transparent plastic does not make photography too easy.

 

DSC00686_zpsu7kmoovw.jpg

 

Anyway, this is stalled for the time being, for lack of blades for the Silhouette. Maybe in Gdansk I will find a model shop with 5thou white plastic sheet, which will be more practical than the transparent one.

 

Thank you all for your interest. Next installment in a few weeks.

 

Hubert.

Edited by MostlyRacers
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  • 3 weeks later...

Hello all,

 

Back from my vacations, with some (little) progress to share, just to up this topic somewaht ;).

 

Whilst I was away, I received some new blades fro the Silhouette, and some extra white card in 5 thou. I also found that Evergreen have introduced the next best thing since sliced bread : black plastic card :frantic: ! I got some in 10 thou thickness.

 

I have tweaked the Silhouette settings to cut the plastic card in both thicknesses, without breaking the blade like the first time ( memo to all with this machine : do not forget to adjust the blade's depth, the cutting speed and the 'paper' thickness in the settinhs before launching a cutting. That should help the life of the blade immensely :BANGHEAD2: )

 

So the idea is to redo the cylinders' heads by stacking thin (0.13 mm / 5 thou) fins and thicker (0.25 mm / 10 thou), smaller diameter discs for the heads' "bodies" (that's a strange description isn't it :) ?). To help visualise the work, the thin fins are white, the "body" discs black

 

DSC00977_zpsoqkkk6nh.jpg

 

DSC00978_zpsvlxcz6yy.jpg

 

I did a first trial. The concept is simple. Stack the cut-out parts until you get the right height. Then the right half of the stack was filed to a bevel. On this bevel, I glued a new smaller diamter stack of fins and "bodies" to represent the finned exhaust valve body. Then the rocker boxes gave been added, in plastic card. Whils studying the pics of the book more closely, I have found out that my interpretation of the position of the exhaust port was wrong. It is not in the middle of the cylinder head, but on the side of the finned exhaust valve body, facing forward.

 

So the cylinder fro the Whirlwinf engine is asymetrcial: the right side of the head (viewed from the front is without cooling fins (bare one at the base), and the intake port is next to it, facing aft. The left side of the hear (the exhaust gases valve/port) is finned for cooling, and the exhaust port is facing forward. Finally, do remember that the rocker arms are behind the cylinders, not in front, like on P&W engines, or later Wroght ones.

 

Here is a side-by-side comparison of a cylinder with my improved head with original Williams' one. The base cylinder is from teh original Williams part.

 

DSC00972_zpslhfdb9ci.jpg

 

It looks a lot better, but there is some fine-tuning to do in the "production run", especially around the rocker boxes covers. Nevertheless, this "production" has begun ...

 

DSC00976_zpsjdwjrkr1.jpg

 

More pics when I have made some progress.

 

Hubert

Edited by MostlyRacers
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