There are a lot of good wood props on the market today for the 25% to the 45% giant scale aircraft. The only draw back to wood is it high compressibility as compared to the carbon fiber props currently available. This compressibility inevitably leads to the prop bolts loosening as the wood compresses under the prop washer. I don’t know of a way to completely solve this problem but increasing the area under the prop washer helps a whole lot.

Using the  DA 100 as an example, the prop washer is 1.65 inches in diameter resulting in a surface area of 2.13 square inches. Our prop washer has a diameter of 2.15 inches and an area of 3.63 square inches or a 70% increase in surface area. You will still have to check your prop bolts but this increased area can be the difference between catching a potential problem before it becomes a disaster.

We have added a line of prop washers that double as nose weight. They are 2 inches in diameter machined from steel. They are available in 4.7 and 6.3 ounce weights. This is the best place for nose weight to get the maximum CG shift for the least added weight. Generally speaking, installing our 6 ounce prop washer is equivalent to taking 12 ounces off the tail.

It is very important to check the amount of prop bolt projecting into the prop drive hub when using these thick washers. There should be at least 3/8" of bolt projecting from the back of the prop or spinner. You may have to purchase longer bolts.

Unfortunately, liability considerations force us to require a signed liability disclaimer with purchases of the heavy propeller washers. We apologize for this but it has become a current day necessity.  The first link is a Microsoft Word document, the second is an Adobe Acrobat file .  Use either one.

DISCLAIMEROFLIABILITYheavypropwasher.doc

DISCLAIMER OF LIABILITY heavy prop washer.pdf

DA or 3W 100	$18.00
DA or 3W 150 & 170	$22.00
DA  50	$18.00
Heavy Washer DA or 3W 100      4.7 oz.	$20.00
Heavy Washer DA or 3W 150, 170      4.7 oz.	$24.00
Heavy Washer DA or 3W 100       6.3 oz.	$21.00
Heavy Washer DA or 3W 150, 170     6.3 oz.	$25.00
		(plus shipping & handling)