With the April 15 deadline looming for tax-deductible contributions to your Individual Retirement Account (IRA), you ought to give consideration to some of the new real-estate investment products that have been custom-tailored for small retirement plans.

Known generically as "mortgage partnerships," they are real estate's advance answer to congressional tax-reform legislation. Rather than stressing shelter from taxes -- the big-bucks write-offs essential to many real-estate partnership offerings in the past -- this year's breed emphasizes interest income, plus participation in operating cash flows and sales proceeds from the underlying properties.

A mortgage partnership may work like this: Your $1,000 to $2,000 IRA contribution is mixed with those of thousands of other small investors. The partnership sponsors then use that pool of cash to make loans to developers or owners of income-producing real estate: hotels, shopping centers, apartment complexes and the like.

The loans may be for land acquisition, new construction, refinancing, rehabilitation or other purposes. Whatever the ultimate function of the loan, though, the partnership promises or guarantees its investors (you and other IRA plan participants) a fixed, annual rate of interest from the mortgages it funds. The partnership also may offer "contingent interest" or "kickers" -- a share of the operating income produced by the real estate it finances, or chunks of the net profits realized upon future sale of the property.

The guaranteed, fixed annual return may be 8 to 10 percent initially. Some partnerships promise gradually rising interest income, up to a minimum of 14 percent during the course of a 9- or 10-year period. The participation or "kickers" vary widely, but all hold out the same theoretical potential: If the property is managed well, if it produces income on schedule and grows in value, you and other partners will receive more than your predetermined, annual interest income. You'll get a piece of the action down the road, swelling your total return well beyond the 10 to 14 percent level you signed up for.

Because your IRA income dollars throughout the term of the partnership are exempt from current taxation, your effective interest return in after-tax equivalent dollars could be 18 to 20 percent or higher, depending on your tax bracket and the success of the partnership.

Publicly offered mortgage partnerships are becoming one of the fastest-growing segments of the real-estate field. Christopher L. Davis, president of the Washington D.C.-based Investment Partnership Association, estimates that $2.5 billion will be raised by mortgage loan funds, up dramatically from pre-tax reform years.

An independent analyst of IRA-oriented investments, William G. Brennan of Valley Forge, Pa., calls the new mortgage partnerships "potentially outstanding vehicles for diversifying your IRA dollars and going after higher returns."

Major institutional sponsors are offering mortgage loan funds in growing numbers, according to Brennan, and are adding income guarantees backed by irrevocable letters of credit from large banks to provide peace-of-mind insurance.

One example of the new trend is the $100 million Guaranteed Hotel Investors fund offered through E. F. Hutton & Co. to finance "all-suite" hotels in Sun Belt locations.

The partnership permits $2,000 minimum contributions for IRA investors. It will provide 10-year mortgages on Embassy Suites hotel projects nearing completion at Dallas-Ft. Worth airport and in Ft. Lauderdale and Tampa, Fla.

Investors will be guaranteed a contract interest rate that begins at 10.25 percent the first year and rises to 14 percent during the ninth and tenth years. The interest payments will be backed by bank letters of credit plus personal guarantees by Robert E. Woolley, the Arizona multimillionaire who first developed the all-suite hotel concept in 1969. Woolley sold his Granada Royale system to Embassy Suites in 1984 for $111 million, according to E. F. Hutton's prospectus.

Besides the guaranteed interest payments, investors also will be entitled to 30 percent of the increase in market value of the hotels during the course of the 10-year loan term.

Brennan noted in an interview that the Guaranteed Hotel Investors fund exhibits several of the pros and cons of mortgage partnerships for small-scale IRA investors. On the one hand, said Brennan, the potential double-digit yields are attractive, the guarantees are impressive, and sponsors and hotel operators have solid track records.

On the other hand, he said, there can be no assurance that these hotels will produce the revenue anticipated by the sponsors to sweeten IRA investors' returns down the road.

Brennan's tactical advice for IRA investors examining mortgage partnerships:

*Go with the offerings that promise moderate, credible interest rates and have sponsors with track records you can check. If a fund says its mortgages will yield 12 to 14 percent immediately -- before the property is even operating -- "they must be financing very risky real estate," said Brennan.

*Avoid funds that are primarily loaning money to other ventures controlled by the general partners. The conflicts of interest aren't worth the risk.

*Avoid funds that intend to finance short-term construction loans, second mortgages and other higher-risk forms of lending.

More than 30 different mortgage funds are on the market. Your stockbroker can guide you through the pros and cons of at least some of them before the April l5 deadline.