Dear Sirs;
I have flown a Chinese made trainer Venus 20 for the past year, now I can take off and land without mishaps and do some basic aerobatics(loops.rolls, snaps rolls.hammer heads. etc). I want to improve my skills, I am wondering whether the world model's Rambler-30 a good choose or not, Can I do knife edge with it? How powerful the engine needs to be ? Thanks.

Get the Rambler 40 its much better as she is a size of a 60 sized plane. She flies well and is lovely. Knife edge? I heard someone who has done it but personally a plane of this sort is not the type that you will fly knife edge with. For that you should get a nice acrobatic or pattern ship.

My Rambler 30 flew absolutely great on an OS 46FX with an APC 11x6. The Rambler will do all the aerobatics you have mentioned. I was not able to get mine to flat spin even though I moved the CG back quite a bit. The rolls on high rate were pretty axial, on low rate they were a little sloppy though. I set my rates at 100% for high rates and 70% for low rates.

The plane will knife edge. You will have to hold some down elevator to get it to fly in a straight line due to the dihedrahl in the wing (about 2 clicks). The plane is a "floater", but handles wind reasonably well.

Couple of other things:

1. You may want to change out the phillips screws for the wing hold downs to socket head screws.

2. The wheel pant attachment is very flimsy. I modified mine by epoxying a piece of 3/32" light ply on the inside of the pant and used the SIG wheel pant brackets. Another option would be to use a pair of "Aressti 40" size pants - they are fiberglass with the ply re enforcement already built in.

3. If you will be flying off of grass, I suggest using larger wheels, the stock wheels are a bit small for grass. If I remember correctly, 2 1/2" are useable with the stock pants.

4. If you want retracts get the Rambler 45. It is slightly larger than the 30, but has pre installed mechanical retracts.

I think you will really enjoy the plane. Except for the items I mentioned, it is a very well made plane, flys exceptionally well and uses decent hardware.