there was quite a long running thread on the british model flying associations site about the vmar beaver 40,myself and many others had big problems with tip stalling on this p.o.s.,all agreed that there was no way a 40 would get it into the air (i fitted a 61),i did better than most,i got it into the air 3 times!,first 2 ended in tip stalls straight in from about 20 feet,the 3rd and last flight seemed to be going well,it was toodling along at about 100 ft altitude,i initiated a left turn and the bloody thing tip stalled at about 40 mph!i did not bother trying to recover the stall as i had had enough of the damn thing!it smashed itself to pieces and i was glad,i will never buy another vmar product again,i agree with the maxim "you pays your money and you takes your choice " but vmar are not cheap,but one thing i am sure of is,they are cr-p!