Thread: 'Any resident Futura experts ?

I have a Robbe Futura SE converted to petrol with a Zenoah G23 engine.

I got it second-hand from a guy who is an experienced fixed-wing flyer and modeller but I think had limited heli experience. So I'm sure he set it up as correctly as he could.

As yet I have not flown the heli but have started it and run the engine a bit, setup the swash and general stuff that I know.

My concern is with the drive belt. It seems about the right tension but what concerns me is that when I press in on the belt I can see that the engine can move ever so slightly. This is going to change the angle of the pully on the clutch bell. What I am worried about is the belt chaffing on the frame and self-destructing.

Anyway, as much as I am anxious to fly it I do not want to be hasty and risk any damage so I am inclined to have someone look at it or perhaps there are things I can check myself to be sure the belt will track properly.

Originally Posted by Tosh

Not an expert by any means but if that engine can move somethings wrong what ever heli it is.

Well, it's a very slight movement mind you. Keep in mind the engine on the Futura does not have a pinion that meshes with a gear, it is belt drive to a middle gear that then meshes with the main drive gear.

So yeah ordinarily the engine just cannot be allowed any movement but this is a bit different creature. (and, the gasser conversion is a proper Robbe part)

Here's the drivetrain on it;



If it was a nitro engine the clutch would be supported at the top with a bearing and there would be a starting lug on top of that. The engine is bolted on to a metal plate that is bolted onto the frame in front. It has a couple metal shims sandwiched in it as well to control the placement of the engine forward or back.

Originally Posted by Tosh

Must be flex in the frames. They came out with some carbon stiffeners when we went to 90s.

Yeah it's hard to tell exactly but I suspect the engine mounts. Perhaps it needs another brace on the other side, bolted to the head or something.

I just need to talk to someone familiar with the gasser conversion in the Futura to see if it's Kosher.

Basically I think as long as the belt rides at the correct angle (not rubbing on the frame) it doesn't matter if the engine mounts flex a little bit so long as it doesn't move a lot. Right now if I press kinda hard on the sides of the belt, the pully on the engine will move inward maybe a millimetre.