It’s fun to put wheels on a rubber band plane. Commercial ones are heavy so interfere with your airplane.
Traditionally people make them from balsa. This is a little tricky.
One method I used in the past is to glue two sheets of balsa together cross grain. Then rough cut out a wheel and glue in a piece of brass as the hub. Mount the hub in a drill chuck and turn it with sandpaper. I’ve used a wood doweling in place of the brass. That works well too. You just slice off and drill it out to match the wire.
In these pictures you can some of the wheels that Lloyd Shales has shared with me. They are laser cut balsa and use brass tubing. This is much easier than making them entirely by hand.
He uses a jig for bending the wire.
I’ve been studying this problem as well. Here’s what I’m doing. I’ve got paper ones that work pretty well. Much lighter than plastic. I’m using some beads as the bearing as well. This is light and inexpensive.
I’m looking at methods of bending the wire too. A CNC wire bender has been in the works but I’m not satisfied that it’s needed yet. I’m still coming up with some alternate bending patterns.
I think both these wheel making methods are nice. I added both Lloyd’s and my wheel samples to my portable lab so I can start testing them and having some fun.
I just boxed up two shipments of wheels to go to two locations in India for testing. If you’d like to test them be sure to send me a note while I’m still working on this.
If you’re carrying lots of stuff you can carry a model plane on your head. Simply put the elastic around your head like a head band. I find it works better if the plane is upside down for some reason.
Dayton Free Flight is based on the Squirrel and looks a lot like a Squirrel but different design constraints were used. The requirement for the model to be entirely stick and tissue was dropped. The Squirrel balsa processing (stripping and chopping only) was dropped. This opens the door to interlocking parts and new tools such as laser cutters. More emphasis was put on cost as well.
The Dayton Free Flight is aerodynamically different than the Squirrel.
The wing is 0 degrees,
tailplane has negative incidence ( 3.6 degrees, 3/16″ over 3″, wing/tailplane measured from fuse center-line) and
the airfoil is different (tissue on top).
Dayton will also have control surfaces! A rudder, elevator and ailerons!
It also has rounded stabilizers so they don’t hook up on branches as much. Might be safer too. The stabilizers are 20lb bond so they can be pre-decorated (or even laser printed). Stabilizers have either no spars or incomplete spars to increase flexibility as well.
There are big differences in construction. The wing is built bottom up. Here is the procedure so far:
1) Lay out tissue and glue stick leading edge.
2) Place 2″ spacers at wing rib positions. Glue trailing edge. Remove wing rib spacers.
3) Glue the notched wing tip ribs. They go vertical on top of the leading and trailing edges.
4) Add shards to wing center. Cap wing root with 4″ balsa strip (not shown below) to form wing handle.
The tail planes are different too:
5) Cut fin, tailplane and winglets out of 20lb bond paper. Mine had a flower on it I painted a while back. Also, cut rudder and elevators.
6) Glue fin and fin spar.
7) Glue tailplane spar and tailplane.
8) Rear motor hanger is glued and capped in place (this step will be moved to an earlier position so the glue will have more time to dry).
9) Glue winglets.
10) Tape wing on using 3m tape. Use two loops. One at the front and one at the back.
Install propeller and elastic motor and we’re ready to go!
Flying
I did a couple of flights. It zoomed a bit on the launch and showed a phugoid behavior as the power came off. Very nice flight. I added a bit of down elevator and tried again. I’m quite pleased.
Next Steps
I felt that 3.5 degree negative tailplane was a bit much but for some reason I wanted to try it that way first so it would be floaty. I will make up some different tail booms with different angles and will see how it behaves.
I am adding a full length tapered aileron to each wing. This will make the Dayton “full house” in terms of control surfaces. It will also increase the wing area and match the rounded stabilizers.
I feel these construction methods are ready for some testing so I will make up some Daytons with different tailplane angles. I’m not settled on the 20lb bond. Brett Herrick has had some luck using it for the whole airplane. So I am giving it a try for stabilizers (eliminating the winglet spars and reducing the tailplane support to reduce weight gain). After the first run, I’d say this looks promising.
Her’es a great tip if you’re a model airplane designer. Carry a portable lab.
This is one of my favorite things about free-flight, rubber-power models. It’s totally portable (not to mention inexpensive). I keep this in my briefcase so I can work on a project whenever I want. At the pub, at a party or a BBQ or where ever I am.
I’ve been working on the Dayton and am now and am about to make a series of prototypes.
I’m going to try the cellophane tape wing mounting technique that was shown to me by Lloyd Shales. I have come up with a simplified wing design that will use tissue and balsa but I am going to try another material for the Winglets. I’m going to drop the shim and change the tailplane angle. Using a toothpick grove and this alternate wing mounting method, I think the glue dry time will be less critical. The tail planes will be an alternate material with partial spars. There will be an elevator and a rudder!
I’m doing a workshop this weekend so if the design shapes up by then I will try the new design.
