tips « Squirrel model airplane!

How to make your Squirrel fly very long or far

By admin, on April 29th, 2012%

A Squirrel can fly quite well with simple hand winding.

Here is a nice flight from last summer that was done with hand winding.

Once you have your Squirrel tuned up nicely you can make it fly longer using the following techniques.

1) You can lubricate the rubber band. Get some Armor All from you nearest hardware store. After the elastic band is tied you can add a couple of drops to the rubber band. The trick is to take the elastic off the model then roll it around in your hand with the product.

This alone will allow the elastic band to take more winding. This reduces the friction on the surface of the elastic.

The elastic will also last longer.

2) You can use a mechanical winder to “stretch wind” the elastic. Here is a video of myself stretch winding a Squirrel. As you can see I have hooked the propeller onto a stationary “winding stooge”. I then take the knot end of the elastic and stretch it (it is still hooked onto the back of the propeller). The winder is used to wind up the elastic very quickly and as the tension builds up I am letting the elastic pull me in towards the model. Once it is wound up enough, I am unhooking the elastic from the winder and then hooking it onto the hook at the back of the model.

3) You can wind the elastic considerably more with these techniques. The rubber that comes with the Squirrel can take about 97 turns per inch before breaking if it is well lubricated and stretch wound. So if the elastic is 8 inches that comes to 776 turns. 9 Inches comes to 873 turns. You’ll want to use about 80 percent of the maximum since the rubber is stressed out quite a bit above 80 percent and will not last very long.

The Squirrel should also work well with an elastic that is as long as 15 inches. That’s a 30″ loop tied. That can accept 1455 turns.

Also a slightly thinner elastic will accept more turns (but it will not provide as much torque) for the propeller. You can shave some of the plastic off the flat surface of the propeller to make it lighter. Some of the motor stick can be removed sometimes as well to save weight. If you do all that you may be able to get the Squirrel to run on 3/32″ rubber instead of the 1/8″ standard. 3/32″ Rubber can take 129 turns per inch. So a 15″ loop can take 1935 turns.

4) If you don’t wait too long after winding I find it helps a bit sometimes as well.

5) In an indoor environment it helps if your plane has a gentle turn. As you can see in the video below it allows the plane to keep flying without hitting anything.

Squirrel Airfoil

By admin, on December 14th, 2011%

You can add a thick airfoil to your Squirrel with just one piece of balsa that is the same as the leading and trailing edge.

Here’s an old document that shoes an easy way of doing it.

In a nutshell you run a spar from winglet to winglet. You attach it to the front of the winglet so it braces the winglet. You cover the top and bottom of the wing with tissue.

You can notch it to go over the wing handle or remove the wing handle. It could be installed before the wing handle and then the wing handle sliced so one piece is ahead of the spar and the other is behind the spar.

Advantages:

-It strengthens the winglets by bracing them.

-It reduces wing warp.

Disadvantages:

-It’s more work.

-Nobody has proven the extra steps are worth it.

Make wheels for your Squirrel

By admin, on March 4th, 2010%

Wheels are fun!

You can make a set of wheels out of some .020″ music wire, 1/8th balsa and some paper. I bent and snipped the wire using needle nose pliers. I made the wheels by cutting them out of 1/8th balsa. I drilled a hole in the middle of each wheel. I made axle tubes by rolling up a piece of paper very tightly with craft glue. I then inserted the axle tubes into the wheel holes using craft glue. Works great! Check out this Squirrel with wheels! Another method is to make the wheels out of cardboard. I have also heard that you can make the hubs out of the shafts of plastic q-tips.

Make a motor stick out of 1/16th inch sheet

By admin, on June 10th, 2009%

I was talking to my friend Bill Khul and we were agreeing that the cost of balsa really adds up when you’re making a lot of airplanes. We discussed some alternate materials but right after the conversation I made this alternate motor stick for the Squirrel that uses less balsa.

You can make a motorstick out of 1/16 x 3/8 inch balsa rather than 1/8 x 3/8 inch. That’s pretty thin but if you put a doubler for the first inch and a half or so, then it fits the standard propeller mount. If you then add a wing mount on top of it all the way back to the fin, then it stiffens the motor stick. The idea is to run it back to the rear motor hangar (toothpick). I added a doubler to the motor stick at the rear of the wing mount as well, just ahead of the toothpick. I then glued the toothpick and fin (don’t forget to add the tissue to the fin before attaching it to the motor stick). So the rear doubler and fin stick brace the toothpick fairly well. In this case I didn’t underhang the toothpick under the motor stick. Instead, it is flush and that is the location to glue to the horizontal stabilizer. After the Stabilizer is in place, you can glue a small block behind the toothpick to help get the elastic motor far enough from the motor stick if necessary.

I think there might be a weak point just behind the front doubler. Also, the toothpick is a bit flexible because it is not secured by sewing thread.

Interestingly, the motor stick is stiffer than a plain one but it’s more twisty. I wonder if this twistyness will provide some Stabilizer Tilt that will counteract torque? Food for thought!