Buying kits is convenient and saves time. You know that there should be enough materials. Distribute the kits to the students and they shouldn’t have to ask endless questions about where to find this piece and that piece. You don’t have to go to one source for rubber, another for propellers, and another for balsa. Everyone should get his or her own instruction sheet.
Denny Dart II flies well indoors or outdoors.
If you don’t mind the extra work and time, building model airplanes from materials can save money. With careful shopping from the right sources and using a "balsa stripper" you can save even more money. No doubt the plastic prop assemblies will have to be ordered. Some hobby shops carry rubber strip but not in a variety of widths and lengths. For more than a couple of airplanes, it is best to purchase rubber by the pound.
	Denny Dart II flying outdoors.

Most hobby shops will carry balsa wood in a variety of sizes, but again if you are building many airplanes this is rather expensive compared to ordering balsa mail order in larger quantities. Mail-order companies selling balsa normally have a minimum order amount and charge shipping so this needs to be considered as well as the price. Depending on where you order from and what you pay, it might be possible to specify the weight of the balsa you purchase.

While it is possible to purchase balsa in pre-cut strips, cutting your own strips will be significantly cheaper. The easiest way to cut balsa strips is with a device known as a balsa stripper. One popular model of balsa strippers costs just a few dollars and holds a common hobby knife blade vertical at the width that you adjust. With one edge of the stripper pushed against the right edge of the balsa sheet, pull the stripper towards yourself.

Master Airscrew balsa stripper under $10 Strip balsa on smooth, flat surface with the edge of stripper pressed firmly against balsa edge. The blade does not pass completely through all the time, so turn over sheet and make a pass from the other side to complete the cut. If the balsa sheet does not look straight, fix this by making a cut with razor blade and straight edge.

       

	Using a balsa stripper only two different thickness of balsa sheet are needed for the Denny Dart II, 1/16" and 1/8".
Balsa strips 3/32" wide created from 1/6" thickness balsa sheet using balsa stripper..

   

Motor sticks are created by stripping 3/8" wide strips from 1/8" thickness balsa. I cut the strips into 12" lengths and then cut the incidence angle in one end of the strip.  After doing many using only a straight edge as a guide to cut the angle, I later built a jig to guide cutting the angle.

Covering

Kits that use the plan for the covering material are adding significant weight with this covering material. The covering also can shrink a significant amount with changes in weather. Although you can purchase tissue for model aviation sources, I have found gift wrap tissue that is comparable weight and much cheaper.      

The biggest expense no doubt will be the propeller/hanger assembly. Most popular are the Midwest or Sig propellers.  Midwest is 6" diameter and is a heavier propeller, but will work very well. Sig prop is 5 1/2" diameter but lighter.  Propellers normally come out of balance (one side heavier than the other), it is worth it to spend time trimming from the heavy side until the propeller blade will remain horizontal. Also watch that the prop shaft is not bent from straight which will also cause vibration.

Normally when you purchase a kit, it only comes with one strip of rubber or a rubber band that is way too short, when that breaks, the plane is grounded or you rob from another kit.  Most modelers purchase rubber in one pound boxes although it  can be purchased in smaller amounts. For model planes that will fly with a six inch plastic propeller, 3/32" wide strip work well, or possibly 1/8" for a larger, heavier plane.

The rubber currently available is either Tan Sport or Tan Super Sport Rubber from FAI Model Supply or Tru Torque Rubber marketed through Tim Goldstein. 
   

I cut and tied the lengths of rubber to save time and waste later (was afraid what might happen to the one pound box of rubber if students were cutting).

Some of the supplies you need can be found from non-modeling sources such as discount stores.

Wax paper used for covering plans can be purchased at the grocery store.	Push pins used to hold balsa strips in place while the glue is drying can be found in a variety of stores.

Ceiling tile makes an ideal building board to push pins through, but two layers of corrugated cardboard can work provided it is perfectly flat.	Single-edge razor blades can be found at building supplies and hardware stores.

Glue

My preference for students is to use the yellow carpenters glue or white glue because it is economical and gives off no annoying odor.  Easy to find in building supply or hardware stores. Can place a blob of glue on waxed paper and apply with a toothpick.

Duco, Ambroid, Testors, or Sigment

Normally dries quickly but gives off an odor.  Duco is a brand found in some hardware stores, similar glues such as Testors, Ambroid, or Sigment will be found in hobby shops.

	Sanding blocks can be easily created using pre-cut lumber, sandpaper, and glue stick. Labeling the top side with sandpaper grit number makes for easy identification.

• Have the materials ready and available. Try to minimize waste.
• Have to get across to the students that it is important to do things in sequence.
• Get across to the students the importance of NOT making their planes heavier than need be.

		On a flat wing I find it easier to cover the wing and then cut part way into the wood at the dihedral joint. The flat wing can be put upside down on a block, press the tips down to the building board, and run glue into the joint.
Don't cut all the way through to the tissue.		The remaining wood and tissue holds the joint together while glue sets up.

Pre-Cutting Parts

For younger children, it can work better to cut all  the parts beforehand and let them assemble the pieces. This is extra work, but not bad for smaller groups. I have been experimenting with creating jigs for all the pieces, which appears to work well and saves some time.  For one session I even color- coded the parts with  felt-tip markers and color-coded a copy of the plan.  All the parts were then put in plastic bags used for newspapers.

Balsa Wood Suppliers

Lone Star Balsa    Info: (972)218-9663 Order: (800)687-5555

Balsa USA

Sig Manufacturing Co. Inc.

Midwest Products Co. Inc.

Peck-Polymers

Indoor Model Supply - contest balsa

www.F1D.biz - contest balsa

Plastic Propeller Assemblies

Midwest Products Co. Inc.

Sig Manufacturing Co. Inc.

Peck-Polymers

Rubber Strip Suppliers

FAI Model Supply

Tru Torque Rubber

Peck-Polymers

Websites With Plans

Free Flight Fantasies

The Plan Page

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