Helicopter Gear is planning to expand its product line, which requires investment of $551,600 in special-purpose machinery. The machinery has a useful life of seven years and no salvage value. The estimated annual results of offering the new products are as follows: Revenue Expenses (Including straight-line depreciation) Increase in net income $ 526,000 (500,000) $ 26,000 be received or paid in cash in the same All revenue from the new products and all expenses (except depreciation) period as recognized for accounting purposes. The payback period for this proposed investment is