stunthanger.com
Building Tips and technical articles. => Building techniques => Topic started by: RC Storick on September 30, 2006, 08:17:27 PM
-
Here is 4 shots of the jigging process. I am building on glass. I am using the Tom Morris Wing jig blocks. The leading edge is done like Tom Morris Millennium wing. Every part on the plane is Slot locked. It should be extra strong and should be light.
How I made the airfoil. First draw a line on a 8.5 X 11 sheet of paper. Fold on that line. You will need to figure out how thick of an airfoil you want and where the high point is. Draw a line at the high point on the fold. Measure up 1/2 that distance from the fold. Take a French curve and draw the front half of the airfoil to the high point from the LE to the high point. Now from the TE to the high point. Cut along that line and unfold. Instant airfoil. Please don't tell me it doesn't work because I have done it at least a 100 times.
-
Sparky,
So your not using any predetermined airfoils like a NACA number or anything? I've also just drawn up my own airfoils before using similar methods. but I figured you probably had a bit more scientific way of design, not that it's really necessary.
So then, what is your opinion on the many different radiuses you could end up with using the french curve or hand drawn methods?
On another note, something I started doing a few years ago is tracing out a root rib outline onto a piece of card stock, cutting it out and saving it, for every model I build. Very soon you end up with a nice inventory of different usable airfoils and it is quite interesting to compare them to each other, epecially when designing that "next' project. ;D
-
Could you post a tighter shot of how the ribs connect to the ibeam?
are they cut to fit square or are the caps fitted to match the inside of the rib ?
-
two more shots. Things are moving slower than usual. I'm looking for the perfect fits.
-
Nice looking work Bob.
-
Sparky,
What are you using to attach the Jig blocks to the glass, Elmer's? Do the blocks get un-useable after a while with glue saturation, or do you sand it down/off? Looks pretty cool at this stage!!
-
Thanks for the close up phto of the ribs. at the front where they meet the leading edge are they sitting on a chin or is it just the reflection I am looking at.
-
there is a 1/8 wide chin as you call it running down the center of the LE.
-
Sparky
Wing looks awesome, this is the one you are drawing as you go?
-
Sparky
Wing looks awesome, this is the one you are drawing as you go?
Yep draw as I go thats the plan. Strictly one off.
-
Sparky, do you use baking soda as a gap filler for the CA joints? On the second set of photos for the wing rib closeups I see white powder on some of the joints. Just wondering if there is a trick there you use on your CA joints.
Steve
-
I use it sometimes but I try to use as little as possible. If you use as little as possible of everything you end up with a lighter airplane.
-
Is that 1/8" chin 1/8" square or is it recessed into the leading edge ?
-
Is that 1/8" chin 1/8" square or is it recessed into the leading edge ?
How is the area nexxt to the fuselage done? is it sheeted ?
-
The root rib is 1.25 wide solid piece sanded to shape. I will take a picture of the LE construction.
-
Well, you certain have plenty of space for a tank. Very nice work Robert.
-
Hi Robert, your new plane is coming along nicely. I am constantly learning new stuff from all of the crew to try on my own models. ;D
I see that you are mounting the under cart forward of the spar, I've often wondered how this would go on an "I-beamer" myself. Most of the classic era I beam plans show the gear mounted on the spar. As we only fly off grass here it requires the wheels further forward of the cg and makes the under cart look a bit "lanky" but moving the gear mounts forward would make the proportions seem better.
In regards to wondering how forward gear mounts would go your pic has already answered my question.
Thanks, Rob.
-
uhm the photo of what I think is leading edge with your hand is a bit bright to see the detail. The photo above that , if that is the same picture makes me think the leading edge is 4 pieces ?
-
Yes. But you do not have to do it this way. You can use 1 piece. I just tried this on this model. Seems to work good though.
-
Couple of comments. I would suggest rounding off the tips of your false ribs. The way you have them, the end of the rib creates a stress point in the covering. Been there, done that.
One thing I have done with beamers is to cover the first bay with silkspan, then cover the first three bays with silkspan, then cover the whole wing. This gives stronger covering at the most stressed areas near the fuselage and strengthens the center section of the wing for handling.
-
I was wondering if you would put up one more photo showing the wing and how it gets shaped.