Baraboo Dave,
Didn't know they had 3-1/2" Astroturf....but it sounds like some fun to walk around on....
As you are suggesting, the best proof of what works for you in your particular grass is to try both the skinny and the wide wheels. On short grass it won't matter. (Think Chris Columbus park in Tucson....) On rocks and gravel and tree sticks it won't matter. The plane's probably going over. (Think sheep pasture....) But if you can get the plane to float on your "Astroturf" or to stop plowing and start planing...then fat wheel might help. I didn't see the previous post you referred to so maybe I go look for that.
If you are talking about the kind of grass that grows, then I know about "Wisconsin Thick." Visited a relative up your way when I was a kid. Thought I'd help out while the family stayed and visited. Tried to cut the front lawn which was about two feet high. Went thru every tool in the barn until it was down far enough that a push mower could get it. Got up the next morning, and--I kid you not--it had grown an inch overnight. At that rate, I'd need to cut it again before we left.... After that, I talked about seeing the Dells every time my Mom was within earshot.
When I looked at the SIG plans, I noted that if you left the top attach point the same and simply swept the gear forward about the same angle that the plans show it going back, you'd have a shot at handling short grass with few issues. The wheels would be a small amount forward of Brett's dimension. But if you lengthen the gear, too, then they're going to bit that much further forward from his recommendation. For good, honest WI grass, you gotta get the prop out of most of it. Hence, the longer legs--or the carpet.
"First, I don't like the chicken leg look, so some disguise would be nice. But I can't get my mind around the fairings of which you speak. I'm thinking that they would appear teardrop-shaped in cross section with a half circle up front and a triangle behind. Correct? Dental floss for light-weight lacing?"
Sorry. I knew my description was weak. I can text you a photo if you PM your number. Else, let me try again. Cut a 1/8" piece of balsa in the planform shape of the fairing that pleases your eye. Like a stretched triangle. Maybe an 1-1/2" chord near the fuse and only 3/4" or so near the axle. Leave a good gap near the fuse so the gear can flex and not hit the fairing. Now, one way to easily attach the fairing is to "tie it on" using Spectra fishing line. But the line will cut thru balsa, so you need to reinforce your balsa fairing. Take a 1/8" square spruce stick (or basswood, or pine, or...) and glue it to the front of the balsa fairing. Now drill an ~.040" hole near the top and one near the bottom right thru the glueline, or in the balsa next to the glueline. Using the Spectra, do about 3-4 wraps thru the hole and around the wire. Pull tight and tie a square knot. Lock the knot with CyA. Go on to the next hole. Going to three holes on a long fairing is tempting, but may not allow the fairing to flex on a long, flexy gear. Two holes on a regular length gear works fine. Put the holes about 1/6th the length of the whole strut in from each end. Yes, you can thin the trailing edge down before you sew them on if that looks better to you. I would stay away from embedding the wire into a hollowed balsa kind of fairing. The first time things flex they will pop apart. Don't worry about drag. It is more important to get the fairing aligned to the airflow. I usually wick some CyA into the joint and let it pop on the first hard flex. The glue residue still keeps things from sliding around after the joint pops. Or, you can do the soldered tin strip deal and forget the Spectra and glue. Lots of ways....
"Finally, your tank discussion gives me pause. So that extra 1/8" on the tank position outboard might be a noticeable disadvantage?"
If you limit the forward sweep to the angle shown, but reversed, and use a standard wedge tank you should clear the gear entirely if you keep the bottom clips low where they belong. (Be sure to put hardwood between the doublers. If the fuse is already done, then you can drill and install some 3/8" wood dowels to spread the load and avoid compressing the fuse.) So not an issue. If you bolted on an aluminum gear and used cap head screws and etc. etc. etc. without regard to the tank choice/installation, then things could get worse in terms of fuel draw. I was merely trying to point that out. Everything is part of one integrated system. One change over here can have an unintended consequence over there. As Brett will tell you, the OS .20 and .25 are not known to have the strongest fuel draw out there when run at the likely rpm.
The Divot
Topic: Landing Gear Placement (Read 1447 times)