There appears that JA had a model for General Tilney in "Northanger Abbey": General Edward Mathew.

I scanned a relevant paragraph from: Wm. Austen-Leigh & Richard Austen-Leigh (Revised by D. Le Faye), Jane Austen, A Family Record, p.67.

It was also while James was living in Overton that he became acquainted with General Edward Mathew and his family, who had recently returned from the West Indies and were living in the old Manor House at nearby Laverstoke. General Mathew had been in the army all his life, serving bravely with the Coldstream Guards in Europe in the mid-i8th century, becoming equerry to George III from 1762-76, seeing further fierce action in the American War of Independence, and finally being made Commander-in-Chief of the Windward and Leeward Islands and Governor of Grenada for the last ten years of his active service. The General 'was in his own house and family a despot whose will no-one could venture to dispute', but although autocratic and hot-tempered was kind-hearted and very generous. His wife, Lady Jane Bertie, was a daughter of the 2nd Duke of Ancaster and sister of the 3rd Duke. The Mathews had three daughters, of whom the second, Anne, (1759-95), was by now turned thirty but still unmarried. She had 'large dark eyes, & a good deal of nose.' and was 'tall and elegant, somewhat pale, with most beautiful eyes... remarkably small-boned and slight.' Anne Mathew must have seen in James Austen her last chance of matrimony, and he had a weakness for elegant aristocratic young women. The General and Lady Jane 'could not have considered the young curate a good match for their daughter, though as his uncle Mr. Leigh-Perrot had no children and he was his father's eldest son, it was possible that he might some day have a comfortable income' - but for Anne's sake they gave their consent to the marriage, and made her an allowance of £100 a year. From the Leigh family James received the vicarage of Cubbington in Warwickshire; this raised his funds to about £200 a year, so on a joint annual income of £300 they were married at Laverstoke on 27 March 1792, Mr. Austen taking the service, and lived for a few months at Court House, Overton, until moving back to Deane parsonage later in 1792. Here they immediately spent £200 in completely re-furnishing the house, and thereafter Anne kept her own close carriage and James had a pack of harriers: 'It is scarcely necessary to add that the income was insufficient.’

Additional information from: http://www.revwar75.com/crown/bio.htm#Mathew

General Edward Mathew
Born: 1729
Died: 1805

Military Career prior to the AWI:
1746: Ensign Coldstream Guards.
1775: Colonel and A.D.C. to the King.

Military Career during the AWI:
1776: As Brigadier brought the Brigade of Guards to America.
15 Sept 1776: Led landing at Kips Bay.
16 Nov. 1776: Took part in the capture of Fort Washington.
19 Feb. 1779: Promoted to Major-General.
May 1779: Led Mathew-Collier Raid to tidewater Virginia.
June 1780: Participated as a volunteer in Knyphausen's Springfield Raid.
1780: Returned to England.
Nov. 1782: Commander in Chief, West Indies.

Military Career after the AWI:
1797: Promoted to General.

I've linked another page below.