Modelers, are they any good techniques to creating frames? I have an aircraft where the rear section of the fuselage is open. There would at least three frames inside. Obviously, this rear section is assembled as two halves.
I guess the best way would be to use card stock and draw the cross section of the fueslage unto the card stock and cut it out. Now, how do I get the correct cross section of that part of the fuelage onto the card stock?
Is there another way I could do this or is this pretty much the best way?
Thanks.
Frames and stringers can be made by using stretched sprue. Just place inside the fuselage and glue in place. After they are dry sand them to proper shape. Bulkheads can be made by using a contour gauge. You can find these for sale at Micro Mark. Just place the contour gauge in the fuselage and it will give you the shape you need to make the bulkhead. Cut just a bit larger than needed and then sand to fit, dry fitting often.
Stretched sprue? I’m not sure I follow you on how to use stretched sprue for that. Is there anywhere on the net that shows a few pics of this?
Lets make sure we are on the same page. Frames and stringers are small strips of metal placed in the fuselage to give them strength. Bulkheads are forged heavy metal, usually placed where strength is needed. Other items are bolted or attached to bulkheads, such as wing mounts. Where two fuselage sections join, a bulkhead will be used as the attachment point.
Frames and stringers are made of thin strips of aluminum, shaped into a “T” “H” “L” or “U” with the skin of the aircraft riveted to them. Bulkheads are forged out of steel, aluminum or titanium. They are a main load bearing part of the aircraft, just as ribs are.
Stretched sprue is the large amount of plastic where your model parts are attached. Some people refer to them as a tree. Take a straight section about 3" long and hold it over a candle. When it gets soft, just stretch it. The speed and length you stretch will determine its thickness.
Dana,
Basically you take a piece of sprue (with out parts attatched of course!) 4 to 6 inches long, holding each end between your thump and forefinger. For a heat source, I use a candle. Hold the sprue is centered over the flame - 1/4 to 1/2 inch above the flame and rotate it between your fingers (don’t hold it close enough that it can catch fire) and gently move the sprue back and forth at the same time so that your are heating an area on the center of the sprue from 1/4 to 3/4 inch long - you want to soften the plastic not melt it. After a few seconds the sprue will soften and sag - at that point, remove the sprue from the heating area over the flame and spread your hands apart (still holding onto sprue of course). The length and diameter of your finished product will depend on how fast and how smoothly you perform the operation - by smoothly, I mean that you maintain the same speed of the stretch until you feel the plastic start to harden - The faster you move, the longer and thinner the final product will be.
Take a couple of hours and practice and you’ll see how easy it is. And you’ll be amazed at the number of things besides antennas and interior framing - pitot tube and gun barrels come to mind and if you take piece of stretched sprue towards a heat source (flame or 100W light bulb) the end will heat up and a small ball, slightly larger than the sprue will be formed at the end of the sprue - makes great throttle, mixture and prop controls for detailing your cockpit - even use as rivets on armor - I’ve even built landing gears out of stretched sprue. All it takes is time and practice.
Ok, we’re using different terminolgy then. With Gulfstream aircraft, which is what I’m used to, a stringer is a non-load bearing horizontal member as you described. In engineering, we are not allowed to attach to or modify a stringer. A frame is a load bearing member running verticle. In Gulfstream aircraft, a frame is what you are calling a bulkhead.
A bulkhead was usually a seperate part that was in the cabin of the aircraft. In fact, we attached nomex or honeycomb bulkheads to frames.
Sorry for the confusion. Below is what I’m trying to produce.
I’d definitely go for the Contour Gauge. Then mark out your frames on sheet styrene and cut out. Longditudinal ribs and stringers can then be made out of the correct thickness of strip styrene. Evergreen do an excellent range of styrene sheet and sections
As for teminology, a bulkhead is solid, such as the engine firewall, ( the same as in ships ) whereas the vertical members in the above photo, as noted by Bones, are frames