Discussion in 'Aircraft & Aviation' started by Gil, Sep 8, 2004.
Best regards, Gil
The following shows the final colors of the engine prior to installation of rocker boxes, pushrods, regulator, oil sump and ignition wiring.
Some have noticed that the picture has changed...,
R-1820-97 Alpha Build
The alpha phase of the R-1820-97 is at an end. I've decided that the present design has too many parts for the average modeler to incorporate into a model and that really is one of the most important criteria of the whole effort. Building a design allows a rethinking of the whole process and of course better ideas evolve as part of this process. The new design will take a couple of days to develop and will be much faster and easier to build. I think it's important to do it now as it will affect all further derivative radial engine designs.
Best regards, Gil
The "alpha" looks great Gil. Since you've decided to make some more design adjustments, this means it can only get better
R-1820-97 Alpha Design Adjustments
The first major change to the design is how the cylinders are built. The part count per cylinder will go from 8 to 4. The shot below is the very first trial of a "rolled" cylinder..., it worked better than was anticipated! A little clean up and it's done. The top cooling fin dome design stays the same but will have an assembly jig for proper alingment and "fiddle-free" assembly.
looks great Gil
Finished second generation design tonight. Build will commence tomorrow.., The parts count is around 68 total compared to something like 167 in the first design. Pretty amazing part reduction and the looks will actually be improved as is the ease of assembly. Cylinder assemblies will not be daunting any longer once you try this technique.
I've noticed that most designers give service to the engine area but the quality is sadly lacking. Best so far was the Ruske Wright Cyclone in the Polikarpov I-16 by Halinski but is not robust enough for most model assemblers to achieve results in the first try.
Other cylinder types can be easily developed using the method making even the Golden Age open cylinder models not only possible but with added attraction points of a highly detailed and realistic looking cylinder body..., Ok, so I'm fairly pleased with the way this design is going but you have to remember the 30 or so drawings that went absolutely nowhere before things started to look up. I still have the rocker boxes to deal with but have an idea of how they can be dealt with now and it's pretty simple too.
Till next, Gil
The following photograph shows the new develpment of the cylinders and the new cylinder assembly spider. Description of the cylinders from left to right:
- Roll-up cylinder test (too big! Paper used was .0085", calculation was for .0075")
- Cooling fin top fit test (too big!)
- Cooling fin top fit test (still a little too big" and don't ask about the sealer test ..., messed up an otherwise good looking cylinder).
An interesting effect of this design is the experimental derivation of the fit. CAD and precise calculations get you in the ball park but then it's built and the fit is off for one reason or another. Simple adjustment by scaling has fixed most of the problems so far between the roll-up cylinder and the top cooling fin assembly. Still looking for an easier way to assemble the two top parts. The assembly jig that I developed was nice but rather useless...,
More as it happens, Gil
Roll-up Cylinder Final
The roll-up style cylinder has reached a satisfactory conclusion with good fit and graphic detail. The below was printed on light gray card stock. Medium gray is more realistic but won't show through form under a cowl that well. hmmmm...., what do you think?
Gil, it looks like it would run.... Cracking project!
Gil, I actually like the looks of the cylinder printed on a lighter paper, but that is just my personal opinion.
Building a R-1820-97 Cylinder Body
The following summarizes the process of building a cylinder for the Wright Cyclone radial engine project. I invite your comments.
Best regards, Gil
That was a most genuinely innovative tutorial and design! For the rest of you guys, might I point out that the Halinski design for a comparative unit of the Cyclone engine (Russian version, in the Polikarpov I 16) comprises 12 parts as compared to the three parts used by Gil. And, after having tried the Halinski version, I think I can authoritatively state that the result with Gil's method should be better while easier and quicker to make.
The clinching detail here is the sanding down of the last bit of the roll-up strip which would make the seam almost invisible, thus eliminating the need for retainer rings at different sections of the cylinder.
Also, please not that the roll-up method provides perfect alignment, as opposed to any method building three separate sections.
And, lastly, no method besides rolling-up would provide for a realistically tapered cylinder.
Note also the absolutely ingenious way of constructing the head part of the cylinder. It would seem almost impossible to design a shape for that complicated form in only two parts, yet here it is!
This is the single most instructive and innovative tutorial and design I've read for a long, long time. Thank you, Gil!
That was a wonderful tutorial Gil. I also liked the part about sanding a tapered edge. However, I see a slight problem arising if one can't find the exact diameter needed to roll the cylinder onto. The engine that I made for the B5N2 Kate was completely solid, so it didn't have a hole running from the top to the bottom. I suppose the guess and check method would work just as well. Great looking engine Gil!
Just find a rod or tube smaller in diameter and wrap it with paper to the right diameter.
Best regards, Gil
I have this safely filed in my "Wonderments" file, for future reference!!
Two comments that you might find helpful.
I prefer to roll strips "dry" with just a dab of glue after the first wind and again at the end to hold the roll closed. Leaves it possible to make any final adjustments to the internal edges to ensure even alignment. A little glue on the end edges then holds all in place.
Has the advantage that the diameter achieved with a given length of strips is more consistent and not influenced by the presence of glue. Also no glue is being squeezed out during the roll.
If you widen the strip for the first couple of winds or so you may be able to form a peg to be plugged into a hole in the crankcase.
Good idea. I've done it both ways and found that if it is wound tight it's difficult to adjust the layers though not impossible. I think the biggest advantage is less glue sloshing around. That's a good thing. The entire top can be brushed with thinned glue after it's wound and set aside to dry. The peg in the bottom is a good idea though I prefer the "spider" structure where each cylinder slips over one of the "spider" arms to align it. Makes life simple especially if you've gotten this far in the build you certainly don't want to mess it up. It would be useful for those desiring to wind capstans and the like for ship models (hose reels, depth charges, torpedoes etc.).
Best regards, Gil
The Halinski "Cyklonski" in 1/16 scale
I built the Russian version of the Wright Cyclone 1820 engine, "the Ruskie Cyklonski" to paraphrase Gil, just in order to have something to compare Gil's efforts to.
It was the first thing I've been able to build for quite some time now, and it felt good. What you see is the engine of the Halinski Polikarpov I-16, but in roughly double scale, 1/16.
The thing that sticks out first of all is the straight front crankcase cover, as compared to Gil's beautiful and correct hemisphere. Second, you'll notice that the top part of the cylinders where the pushrods connect are not to well designed. They will do in 1/33, stuck under an almost closed engine cowl, but in 1/16 they leave a lot to be desired.
This is as complete as you'll get it from the Halinski kit. But of course the engine is far from complete if you want to make a decent model of it. Lacking are induction and exhaust tubing, the oil pump (or whatever that thingamujig at the bottom of the crankcase is), and all wiring for ignition.
All of these details add a lot to the impression of the engine, and it will take some time to figure out how to accomplish them, particularly since I've gone and stuck the engine to the firewall already.
Oh, and of course there's an electric motor inside the crankcase. Easy to accomplish in 1/16.
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