Civil Air Contest
- Thread starter Samh
- Start date
CatholicFlyer
Active member
same here, table is kind of full with this monster, B-52
CatholicFlyer
Active member
will do.
Samh
Elite member
King air is mine unless you want to join me. I also might do a decathlon or T-28
Danal The Dragon
Member
I have built a nomad
Not a new design or a part of the contest, but since the focus here is on civil aviation I figured I'd share here. I'm starting the rescue/rebuild of my Carbon Z Cessna 150. The rebuild will involve a conversion from a 150 to a 152 that I got my private pilot's license in. The later 150s and early 152s are pretty identical apart from the air intakes on the cowl and a split rear window on the 152, so those will be some easy visual mods. I will be buying a replacement rudder form horizon as the one that's on right now is a bit crunched. It's still flyable, but doesn't look great. I'll be adding some extra detail bits too. The exhaust on the 152 was re routed with the new cowl, so I will be moving the stock pipes to the correct locations as well as adding additional antennas. The stock CZ representation is a fantastic sport scale representation of the real thing but it has a few flaws. Tire size is a bit off scale, so those will be replaced, some extra detail bits like hand holds will be added, and a few panel lines which were neglected. I found some great, much more scale, window decals available through Callie Graphics which will make a fine addition, and to top it all off it's getting the tri-color paint scheme that N4655H carries right now.
JTarmstr
Elite member
The q400 is nice, however, the dash 8 series 100 had a way smaller fuselage so I think I could make that with less wing loading, it doesnt have the same look to it though.
https://aerofred.com/data/thumbnail..._dash_8_series_100__200__q200_1983_canada.jpg
CatholicFlyer
Active member
@Chuppster @DamoRC and anyone here, the Gulfstream has the weird wing tips pointed up, I've read they helped to cut drag, so when doing two such wings, will there be even less to zero drag or what will happen and yes it will look like a biplane. I got the fuselage setting with the glue in the creases to hold the folded shape.
Chuppster
Well-known member
By my understanding, the winglets on the tips on a lot of civilian aircraft help reduce drag by cleaning up the wingtip vortex created by air rolling off the edge of the wing. I'm not sure they help much on stuff as small-scale and - dare I say- crude as our DTFB airplanes. They would not lower the drag to zero, it's mainly just an efficiency thing to get a little more speed and range out of an airplane that's made to cruise.
CatholicFlyer
Active member
interesting.
Winglets are a tricky little subject. Basically the reason that heavier aircraft have them is because of their excessive wake vortexes. Be cause of the way that wings make life there will always be a higher pressure below the wing than there is above. This works fine and dandy mid span because you won't get any "spill." Out at the wing tips the air want to move from the area of high pressure to the area of low pressure (bottom to top) and air on the bottom of the wing will slip around the wing tip creating a tornado like wake which can extend FAR behind a heavy aircraft. In ideal conditions a heavy aircraft may leave several thousand feet (there are even a few documented cases of nearly 10 miles!) where the vortexes can have an effect on other aircraft. These vortexes also cause drag, which is where the winglets come in. The flared tips that you see on most modern airliners and a lot of new business jets act as a fence for the air trying to spill up and over, thus preventing vortex drag and keeping air cleaner for other traffic. In terms of aerodynamics, they really don't do as much as you'd think though. Winglets only really help to improve fuel efficiency, and even then it's only 2-4% total savings.
Now, onto biplanes. Biplanes get a weird thing called interference drag. The closer the two wings are together the more the design will suffer from this effect. Biplanes are great for retaining stability at low airspeed, but they take a massive aerodynamic hit because of the extra structure needed to support the extra structure. In addition since a lot of drag comes from "induced drag," or drag that is a direct byproduct of lift an extra wing will only increase your total drag, regardless of winglet design.
What you may want to look into is a box wing design, which is a promising little development that should cut wake vortexes to the bare minimum as well as give you that kind of biplane aesthetic.
Good luck with your build, take your time and you should do just fine.
Just as a general rule of thumb, as you increase lift you proportionally increase drag. Airspeed is in inverse square to power. If you want to go 4 times as fast you need 16 times the power. I do have a little bit of a background in aerodynamics, so if you have any other questions you can drop me a line.
CatholicFlyer
Active member
thanks. will look into the box
CatholicFlyer
Active member
hey, on the engines, what would two prop motors do on the same area where the usual EDFs, would they work being that far back?
So long as the aircraft balances they should work fine there. It will actually be much more efficient if you use props.
CatholicFlyer
Active member
awesome. that is very interesting to learn.