I read Tom Cleaver’s review and build of Czech Model Curtiss A-12 Shrike and was concerned about finding a correct engine for the poorly designed one Tom discovered in the kit. I checked my spares and found Engines and Things R-1820 #48072. According to a picture on p. 325 of “Allied Aircraft Piston Engines of World War II”, by Graham White, and pictures of the aircraft on the internet, this is the correct engine for this plane.
Questions:
Has anybody corrected the cowling? How was itdone? I don’t want to use an P-26 cowling because that would make the doner kit useless.
Does anyone know how the collector ring was attached? Pictures seem to show that it doesn’t form a complete circle behind the cylinders. Also, the exhaust pipe, which can be seen in pictures of the port side of the plane, seems to have a second input tube as if all cylinders except one empty into the collector ring and then to the exhaust pipe but one cylinder has its own pipe seperate from the collector ring wihich dumps directly into the exhaust pipe. See: usaaftroopcarrier.com/images/CHY_and_Curtis_A-12.jpg for a picture of the exhaust.
Is there a cut away drawing of the A-12? Where is it located?
Does anyone know of a book about the Chinese air force in the Second Sino-Janapese war which deals mainly (if not exclusively) with the period 1934 or '35 to 1941? What’s the name, author and ISBN?
I can give you a little help on the exhaust collector ring. It will not be a complete circle, but will split at the top two cylinders. The main pipe will curve around behind the engine at about the same diameter as the engine, and will make a 90 degree bend to mount at an exhaust port on one of the top cylinders, usually the one closest to the big exhaust pipe location. Then, the other side will do the same, and they meet at the big exhaust pipe. There is a short, curved stub pipe at each cylinder the ring passes, and the one at the exhaust pipe is usually straight. The whole assembly is held to the engine by the flanges at each stub pipe bolting to the exhaust studs, then there are a few support brackets around the engine. The ring has to be made so that each stub pipe meets its respective cylinder exhaust port exactly, and that is tough in 1 to 1 scale! If you can’t see the individual pipes under the model’s cowl, you can always epoxy the ring to the back of the engine to give the impression of a collector.
These are R-1820-97s, or "Cyclone 9"s, but From what I can see of the A-12’s exhaust system vs the B-17’s , the collector rings are pretty much the same, although obviously not “interchangable”…
More from hanging around round engines. If you can find some internet photos of the EAA’s Ford Tri-Motor, look at the outboard engines. It is the exact set-up I described, but there is no cowling to obscure the view.
Thank you for the pictures. They illustrate well what you wrote and are of great assistance to me. Being new to computers, I greatly appreciate the time and effort you and Hans Von Hammer have put into answering my questions.
