I wonder if anyone on here can tell me the actual differences between an Airbike wing and a standard Minimax wing?
Can an Airbike wing be used on a Minimax, or will it require lots of major surgery to modify it to fit?
The reason I ask is that after my plane got damaged last week, someone has kindly asked if I'd be interested in a pair of Airbike wings, but I don't know how different they are from the Minimax wing, so have no idea whether they can be fitted straight on, or whether they'll require major work to get them to fit. So if anyone on here happens to know what's needed, or has already made the conversion, then I'd be very grateful if they could let me know.
I might be able to help but first I'd like to know which model do you consider the "standard Minimax"? Briefly. Airbike wing is one bay longer, 3 drag braces (anti drag?) vs 4 (?), and the root fittings attach near the bottom spar cap. Might very well be possible to make the changes. If the Airbike got away with 3 drag braces on a longer wing might it be OK on a MiniMax? Or add the 4th to be safe, but normally they are fitted early in construction as you have to rack the wing to fit them. Could cut it in half then splice glue back together inside the wing?
Thank you for your information. My plane is a Rotax 447 powered '88', which is pretty close to a hybrid 1030/1100. In the UK when the plane was first looked at, the CTO of the PFA (as it was then) decided that some things needed changing. He insisted that all the teleflexes were increased in size, that an extra one was added for the elevator, and that the seat belt anchoring points be changed to remove the 90 degree bend in the cables at the rear of the fuselage. Once these changes were made he was happy for people to build the plane in the UK.
Mine is one of those early ones, which were designated as the 88, presumably because that's when it was approved. It had the light wing (and therefore only 3 anti-drag braces) and tail, and the short narrow fuselage of the 1030, along with the structural seat back at station 4. It was given a VNE of 90mph instead of the 100mph of the later 91 models.
So for me the wings could be either the light wing or the heavy wing design. As such the Airbike wings might be suitable, although I think I'd be inclined to remove any extra length from the outboard end as I don't have that much room in the hangar.
I also worried about the attachment points at the inboard end, and I don't know how much work would be required to modify the Airbike wings to move the attachments. The other thing I was worried about was that the angle of the wooden bracing inside the wing at the strut attachment points would be wrong, because I believe in the 'max the angle of the wooden braces inside the wing is the same as that of the struts outside it, and I'm not sure if the Airbike uses the same angle for the struts. Related to that there's also the worry that the distance from the inboard end to the strut attachment points might be different. This would mean building struts that are either longer or shorter than the normal 'max ones, so some detailed measurements would be required before starting on any rebuild if I used the Airbike wings.
So, plenty of food for thought before I decide what to do.
At this point, I'd be inclined to take them and have a look. The inboard mountings I believe are different in placement. As for the struts, I wouldn't consider making the new ones until I had the wings mounted and outboard ends supported to determine the mounting angle. (There is a word for this angle, I just have forgotten it, someone please chime in here and correct me). As for the extra wing length, I might be inclined to leave it, as it may add lift(and drag), but may require other changes, who knows.
I only have time right now for a short response but I'm pretty sure the strut fittings,block angle, and dimension to it from the root is identical. Will confirm later. Forgot to mention there may or may not be changes to the spar cap doublers.
And the aileron control horn is different but not a insurmountable problem. Bob I have plans for all the heavier,faster models but no info for the lightest,slowest or 88 model so can not comment on differences in the spar cap doublers. Indeed the strut bracket/framing/dimensions is all the same Airbike vs HighMAx,Eros,1500Sport,1600 Sport and Vmax but none of these are the "narrow body" you have. The root fitting per se' is identical but its spacing from the end of the spar is different. If you want to see a particular Airbike drawing let me know and I can post it. And thinking today about moving the root fitting to the opposite spar cap.....might be a bugger of a job considering the nose skin and first two ribs are already installed and in the way. I think I would just build new wings from scratch. Convince yourself it will be fun. Have you inspected the crashed wings yet?
Not yet. I've been busy doing other things up till now, and this next week me and the missus are away for a few days. So I won't get to look at anything before next weekend at the earliest. However, once I settle in to giving everything a good look over I'll have a much better idea of exactly how much work will be involved in getting the wings back into flyable condition.
The fuselage isn't so bad. Where the tail hit the ground the fin being straight on to the impact sent the loading straight into the tail end of the fuselage. The main four longerons all seem to be fine, but many of the diagonals have popped their joints either at one end or both. So there's going to be some work to do getting them reglued and adding gussets where I think appropriate. Other than that, the front of the fuselage folded in on itself, so I'll have to cut away all the floor in front of the first bottom cross member and see about rebuilding it all from there forward.
At first glance the tail feathers appear to be remarkably undamaged, but I think I'll take the covering off anyway and look for any loose joints, and/or splitting of any of the wooden framework.
The whole undercarriage needs to be built from scratch, and a new axle and struts fabricated. I already have the axle tubing, but the struts and the undercarriage legs I'll have to get the material for before I can begin building it.
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