How is possible the British to win? And if yes what the impact to future revolutions and to Britain and America?
nova2010
Plenty of ways. Early opposition was limited and divided with considerable loyalist support. An additional victory at the right point could make the rebellion seem totally hopeless and would restrict the opposition to hard-liners. Similarly the right approach to moblising local support along with possibly some concessions could have further isolated the rebels. Stopping them gaining control of significant areas, which both undermined believe in British rule and allowed intimidation/persecution of alleged loyalists.
Possibly even avoiding the Yorktown defeat and hanging on could have been decisive. If the French fleet had been defeated then not only could they not have blockaded Cornwallis but also the enemy couldn't have landed the French troops and artillery to persecute the siege. By this time, faced with the traditional foreign enemies rather than an unpopular civil war, Britain was moblising more successfully and the navy especially was getting up speed. There were financial problems but not as bad as for the French or rebels and with a growing threat to their Caribbean colonies the French might have decided to cut their losses. Without the funds and weapons from the French rebel would have had to further reduce their activities.
In terms of the situation after the war a lot would depend on how the rebellion was ended. I would expect that the colonies would finally pay some taxes under the settlement, although probably still far less than the core British. They might also rely more on local loyalist forces for the army. [Which would ease the problem somewhat as all Britain was asking for was a contribution towards the costs of defending the colonies]. This might however led to later full incorporation of the colonies into the kingdom. However this is unlikely as the travel and time difficulties would be a problem until modern technology becomes available. Even more importantly that would also mean the colonies fully contributing financially which would be unpopular.
More likely I think would be a relationship such as with Canada. Britain would continue to control foreign affairs and provide the defences other than local militia while N America would be the centre of attention for emigration and investment. There might well be a clash at some point over slavery, which would depend on how its handled. If the slave owners are able to claim they are defending 'American liberties' they might attract support from the north in which case it might be a new full scale civil war which the rebels might even win, especially if they can get foreign support. Alternatively if they can be isolated and its a case of the bulk of the north plus Britain against a sectional interest in the south then it should be over pretty quickly.
A British North America [BNA] would tend to display more independence earlier than Canada simply because its larger and doesn't have a much more powerful and sometimes hostile neighbour. The other point that would probably influence relations is the wider status of Britain in the world. If the homeland is threatened by a major state in a position to dominate Europe you could see a rallying around as occurred during the two world wars. Also, because of its power and increasing trade interests BNA would probably get involved in other areas, such as defence of interests in China, or Australia say.
Basically a British victory in 1770-80 could led to an extended period of unity and power or with the wrong circumstances lead to prolonged internal conflict and possibly an even more bitter parting of the way.
Steve