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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 2)*

GenCorp Incorporated

(Name of Issuer)

Common Stock

(Title of Class of Securities)

368682100

(CUSIP Number)

December 31, 2010

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

x Rule 13d-1(b)

¨ Rule 13d-1(c)

¨ Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 2 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Multi-Strategy Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 3 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Multi-Strategy Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 4 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Multi-Strategy Fund, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 5 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Multi-Strategy Fund, Ltd.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 6 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Concentrated Convertible Arbitrage Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 7 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Concentrated Convertible Arbitrage Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 8 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Concentrated Convertible Arbitrage Fund, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 9 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Concentrated Convertible Arbitrage Fund, Ltd.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 10 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Credit Arbitrage Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 11 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Credit Arbitrage Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 12 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Credit Arbitrage Fund, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 13 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Credit Arbitrage Fund, Ltd.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 14 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Diversified Convertible Arbitrage Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 15 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Diversified Convertible Arbitrage Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 16 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Diversified Convertible Arbitrage Fund, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 17 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Whitebox Diversified Convertible Arbitrage Fund, Ltd.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 18 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Pandora Select Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     IA

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 19 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Pandora Select Partners LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 20 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Pandora Select Fund, LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 21 of 25

CUSIP No. 368682100 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Pandora Select Fund, Ltd
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION     British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:		5	SOLE VOTING POWER     0
		6	SHARED VOTING POWER     0 (See item 4)
		7	SOLE DISPOSITIVE POWER     0
		8	SHARED DISPOSITIVE POWER     0 (See item 4)
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 (See item 4)
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)     0% (See item 4)
12	TYPE OF REPORTING PERSON*     PN

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SEC 1745 (2-02)

Page 22 of 25

CUSIP No. 368682100 13G

Item 1.	(a)	Name of Issuer
		GenCorp Incorporated
	(b)	Address of Issuer’s Principal Executive Offices
		Highway 50 and Aerojet Road Rancho Cordova, CA 95742-7012
Item 2.	(a)	Name of Person Filing
		This statement is filed by:
		(i)	Whitebox Advisors, LLC, a Delaware limited liability company (“WA”);
		(ii)	Whitebox Multi-Strategy Advisors, LLC, a Delaware limited liability company (“WMSA”);
		(iii)	Whitebox Multi-Strategy Partners, L.P., a British Virgin Islands limited partnership (“WMSP”);
		(iv)	Whitebox Multi-Strategy Fund, L.P., a Delaware limited partnership (“WMSFLP”);
		(v)	Whitebox Multi-Strategy Fund, Ltd., a British Virgin Islands international business company (“WMSFLTD”);
		(vi)	Whitebox Concentrated Convertible Arbitrage Advisors, LLC, a Delaware limited liability company (“WCCAA”);
		(vii)	Whitebox Concentrated Convertible Arbitrage Partners, L.P., a British Virgin Islands limited partnership (“WCCAP”);
		(viii)	Whitebox Concentrated Convertible Arbitrage Fund, L.P., a Delaware limited partnership (“WCCAFLP”);
		(ix)	Whitebox Concentrated Convertible Arbitrage Fund, Ltd., a British Virgin Islands international business company (“WCCAFLTD”);
		(x)	Whitebox Credit Arbitrage Advisors, LLC, a Delaware limited liability company (“WCRAA”);
		(xi)	Whitebox Credit Arbitrage Partners, L.P., a British Virgin Islands limited partnership (“WCRAP”);
		(xii)	Whitebox Credit Arbitrage Fund, L.P., a Delaware limited partnership (“WCRAFLP”);
		(xiii)	Whitebox Credit Arbitrage Fund, Ltd., a British Virgin Islands international business company (“WCRAFLTD”);
		(xiv)	Whitebox Diversified Convertible Arbitrage Advisors, LLC, a Delaware limited liability company (“WDCAA”);
		(xv)	Whitebox Diversified Convertible Arbitrage Partners, L.P., a Cayman Islands limited partnership (“WDCAP”);
		(xvi)	Whitebox Diversified Convertible Arbitrage Fund, L.P., a Delaware limited partnership (“WDCAFLP”);
		(xvii)	Whitebox Diversified Convertible Arbitrage Fund, Ltd., a Cayman Islands business company (“WDCAFLTD”);
		(xviii)	Pandora Select Advisors, LLC, a Delaware limited liability company (“PSA”);
		(xix)	Pandora Select Partners, L.P., a British Virgin Islands limited partnership (“PSP”);
		(xx)	Pandora Select Fund, L.P., a Delaware limited partnership (“PSFLP”);
		(xxi)	Pandora Select Fund, Ltd., a British Virgin Islands international business company (“PSFLTD”);
		(xxii)	HFR RVA Combined Master Trust, a Bermuda limited partnership (“HFR”);
		(xxiii)	IAM Mini-Fund 14 Limited, a Cayman Islands Corporation (“IAM”);
	(b)	Address of Principal Business Office or, if none, Residence
		The address of the business office of WA, WMSA, WMSFLP, WCCAA, WCCAFLP, WCRAA, WCRAFLP, WDCAA, WDCAFLP, PSA, and PSFLP is:
		3033 Excelsior Boulevard Suite 300 Minneapolis, MN 55416
		The address of the business office of WMSP, WMSFLTD, WCCAP, WCCAFLTD, WCRAP, WCRAFLTD, PSP, and PSFLTD is:
		Trident Chambers, P.O. Box 146 Waterfront Drive, Wickhams Cay Road Town, Tortola, British Virgin Islands
		The address of the business office of WDCAP, and WDCAFLTD is:
		Trident Trust Company (Cayman) Limited One Capital Place, 4th Floor, P.O. Box 847GT Grand Cayman, Cayman Islands, B.W.I.
		The address of the business office of HFR is:
		HFR RVA Combined Master Trust 65 Front Street Hamilton, HM 11, Bermuda
		The address of the business office of IAM is:
		IAM Mini-Fund 14 Limited Boundary Hall, Cricket Square George Town, Grand Cayman, KY1-1102 Cayman Islands
	(c)	Citizenship
		WA, WMSA, WMSFLP, WCCAA, WCCAFLP, WCRAA, WCRAFLP, WDCAA, WDCAFLP, PSA, and PSFLP are organized under the laws of the State of Delaware; WMSP, WMSFLTD, WCCAP, WCCAFLTD, WCRAP, WCRAFLTD, PSP, and PSFLTD are organized under the laws of the British Virgin Islands; and WDCAP, and WDCAFLTD, and IAM are organized under the laws of the Cayman Islands; HFR is organized under the laws of Bermuda.
	(d)	Title of Class of Securities
		Common Stock
	(e)	CUSIP Number
		368682100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
	(a)	¨	Broker or dealer registered under section 15 of the Act.
	(b)	¨	Bank as defined in section 3(a)(6) of the Act.
	(c)	¨	Insurance company as defined in section 3(a)(19) of the Act.
	(d)	¨	Investment company registered under section 8 of the Investment Company Act of 1940.
	(e)	x	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E).
	(f)	¨	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F).
	(g)	¨	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G).
	(h)	¨	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act.
	(i)	¨	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940.
	(j)	¨	Group, in accordance with § 240.13d-1(b)(1)(ii)(J).

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 23 of 25

CUSIP No. 368682100 13G

Item 4.	Ownership
	(a)	Amount Beneficially Owned
		WA, acting as an investment adviser to its client, is deemed to be the beneficial owner of 0 shares of Common Stock of the Company. WMSA, is deemed to beneficially own 0 Shares of Common Stock of the company. WMSP is deemed to beneficially own 0 shares of Common Stock as a result of its ownership of Common Stock of the company WMSFLP is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership of Common Stock of the company WMSFLTD is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company WCCAA, is deemed to beneficially own 0 Shares of Common Stock of the company. WCCAP is deemed to beneficially own 0 shares of Common Stock as a result of its ownership of Common Stock of the company WCCAFLP is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership of Common Stock of the company WCCAFLTD is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company WCRAA is deemed to beneficially own 0 Shares of Common Stock of the company. WCRAP is deemed to beneficially own 0 shares of Common Stock as a result of its ownership of Common Stock of the company WCRAFLP is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership of Common Stock of the company WCRAFLTD is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company WDCAA, is deemed to beneficially own 0 Shares of Common Stock of the company. WDCAP is deemed to beneficially own 0 shares of Common Stock as a result of its ownership of Common Stock of the company WDCAFLP is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership of Common Stock of the company WDCAFLTD is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company PSA, is deemed to beneficially own 0 Shares of Common Stock of the company. PSP is deemed to beneficially own 0 shares of Common Stock as a result of its ownership of Common Stock of the company PSFLP is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company PSFLTD is deemed to beneficially own 0 shares of Common Stock as a result of its indirect ownership Of Common Stock of the company HFR, is deemed to beneficially own 0 Shares of Common Stock as a result of its ownership of Common Stock of the company IAM, is deemed to beneficially own 0 Shares of Common Stock as a result of its ownership of Common Stock of the company As a result of the relationship described in this statement, each of WA, WMSA, WMSFLP, WMSFLTD, WCCAA, WCCAFLP, WCCAFLTD, WCRAA, WCRAFLP, WCRAFLTD, WDCAA, WDCAFLP, WDCAFLTD, PSA, PSFLP, and PSFLTD may be deemed to possess indirect beneficial ownership of the shares of Common Stock beneficially owned by each of WMSP, WCCAP, WCRAP, WDCAP, PSP, IAM, and HFR. WA, WMSA, WMSFLP, WMSFLTD, WCCAA, WCCAFLP, WCCAFLTD, WCRAA, WCRAFLP, WCRAFLTD, WDCAA, WDCAFLP, WDCAFLTD, PSA, PSFLP, and PSFLTD each disclaim indirect beneficial ownership of the shares of Common Stock except to the extent of their pecuniary interest in such shares.* Based on the relationships described herein, these entities may be deemed to constitute a “group” within the meaning Of Rule 13d-5(b)(1) under the Securities Exchange Act of 1934. The filing of this statement shall not be construed as An admission that WA, WMSA, WMSP, WMSFLP, WMSFLTD, WCCAA, WCCAP, WCCAFLP, WCCAFLTD, WCRAA, WCRAP, WCRAFLP, WCRAFLTD, WDCAA, WDCAP, WDCAFLP, WDCAFLTD, PSA, PSP, PSFLP, PSFLTD, IAM, AND HFR are a group, Or have agreed to act as a group.*
	(b)	Percent of Class
		WA beneficially owns 0 % of the company’s Common Stock.* WMSA is deemed to beneficially own 0 % of the company’s Common Stock WMSP is deemed to beneficially own 0 % of the company’s Common Stock WMSFLP is deemed to beneficially own 0 % of the company’s Common Stock WMSFLTD is deemed to beneficially own 0 % of the company’s Common Stock WCCAA is deemed to beneficially own 0 % of the company’s Common Stock WCCAP is deemed to beneficially own 0 % of the company’s Common Stock WCCAFLP is deemed to beneficially own 0 % of the company’s Common Stock WCCAFLTD is deemed to beneficially own 0 % of the company’s Common Stock WCRAA is deemed to beneficially own 0 % of the company’s Common Stock WCRAP is deemed to beneficially own 0 % of the company’s Common Stock WCRAFLP is deemed to beneficially own 0 % of the company’s Common Stock WCRAFLTD is deemed to beneficially own 0 % of the company’s Common Stock WDCAA is deemed to beneficially own 0 % of the company’s Common Stock WDCAP is deemed to beneficially own 0 % of the company’s Common Stock WDCAFLP is deemed to beneficially own 0 % of the company’s Common Stock WDCAFLTD is deemed to beneficially own 0 % of the company’s Common Stock PSA is deemed to beneficially own 0 % of the company’s Common Stock PSP is deemed to beneficially own 0 % of the company’s Common Stock PSFLP is deemed to beneficially own 0 % of the company’s Common Stock PSFLTD is deemed to beneficially own 0 % of the company’s Common Stock HFR beneficially owns 0 % of the company’s Common Stock.* IAM beneficially owns 0 % of the company’s Common Stock.* The percentage of Common Stock reportedly owned by each entity herein is based on 59,000,000 shares of outstanding Common Stock of the Company, which is the total number of shares issued and outstanding on November 30th, 2010.
	(c)	Number of shares as to which such person has:
		(i)	Sole power to vote or to direct the vote
			0
		(ii)	Shared power to vote or to direct the vote
			WA has shared voting power with respect to 0 shares of the Issuer’s Common Stock. WMSA, WMSP, WMSFLP, and WMSFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WCCAA, WCCAP, WCCAFLP, and WCCAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WCRAA, WCRAP, WCRAFLP, and WCRAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WDCAA, WDCAP, WDCAFLP, and WDCAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. PSA, PSP, PSFLP, and PSFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock.
		(iii)	Sole power to dispose or to direct the disposition of
			0
		(iv)	Shared power to dispose or to direct the disposition of
			WA has shared voting power with respect to 0 shares of the Issuer’s Common Stock. WMSA, WMSP, WMSFLP, and WMSFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WCCAA, WCCAP, WCCAFLP, and WCCAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WCRAA, WCRAP, WCRAFLP, and WCRAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. WDCAA, WDCAP, WDCAFLP, and WDCAFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock. PSA, PSP, PSFLP, and PSFLTD have shared voting power with respect to 0 Shares of the Company’s Common Stock.
Instruction. For computations regarding securities which represent a right to acquire an underlying security see §240.13d3(d)(1).
Item 5.	Ownership of Five Percent or Less of a Class
	If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following  x*.
Instruction. Dissolution of a group requires a response to this item.
Item 6.	Ownership of More than Five Percent on Behalf of Another Person.
	Not Applicable.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group
	See Item 2
Item 9.	Notice of Dissolution of Group
	Not Applicable
Item 10.	Certification
	By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

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SEC 1745 (2-02)

Page 24 of 25

CUSIP No. 368682100 13G

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

02/11/11

Date

/s/ Jonathan D. Wood

Signature

Jonathan D. Wood as Chief Financial Officer of Whitebox Advisors, LLC.

Name/Title

The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative other than an executive officer or general partner of the filing person, evidence of the representative’s authority to sign on behalf of such person shall be filed with the statement, provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title of each person who signs the statement shall be typed or printed beneath his signature.

NOTE: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7 for other parties for whom copies are to be sent.

Attention: Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001)

fb.us.1260302.03

** SEE INSTRUCTION BEFORE FILLING OUT **

SEC 1745 (2-02)

Page 25 of 25