Originally Posted by Telemaster Sales UK

Or maybe the engine was overheating and a look at the airflow was in order.

However, to revert to your original question, I own the 25cc version of this engine and that was the original engine used in the DB Sport and Scale 1/4 scale SE5. Their 88 inch wingspan Hawker Hurricane also used the same engine.That gives you plenty of scope!

http://www.dbsportandscale.com/