We used fork bolts and eye bolts for hinges and other control linkages on our E-Hawk (EMG-6). They are a clean solution but I would have to echo the sentiments above regarding cost. I recall having to pay ~$25 per for some of the AN fork bolts (the mating eye bolts are more reasonably priced at around $5).20 each AN42 bolts would be needed for the ailerons, elevators and rudder. Total cost would be in the $200 to $300 range, depending on the sizes selected.
Edit. Just looking around, it looks like some may be available for about half of the above.
As in Post # 101 but VB has spoken and needs to be heard.I'm not quite sure I understand the design you're describing. Do you have any examples you could refer us to (model or full size)?
Why? Because it carries the stigma of being developed for - models?No, just no, on fabric or laced hinges.
The Skypup uses sewn hingesWhy? Because it carries the stigma of being developed for - models?
If there exists a real reason, rather than an emotional reaction, then I would genuinely like to hear it.
Dacron has a pretty good fatigue profile, and with multiple strips a quite progressive and observable failure rate. On top of that you have an automatically sealed control gap.
Because it is not "standard aircraft parts or process".....Is there one LSA, or Certified aircraft or STC that uses it, I would be interested to see it. Were one such as a Rutan to do all the analysis and testing such as he did for the Vari-Easy and was at a FISDO with understanding inspectors perhaps,..... but to suggest it as a high-school project is not what I believe is appropriate.Why?
Maybe, but part of this project is learning how to evaluate the options presented. So far they appear to be doing an excellent job. If I thought the option was inherently unsafe I would not have suggested it.but to suggest it as a high-school project is not what I believe is appropriate.
Good point, post if not too much trouble, certainly a wing that deflects is going to want to twist two eye bolts, perhaps piano hinge is better where it still deflects but does not twist, and if the hinge is short pieces (2" ?) the deflection through the pin is very small, plus one would be able to have at least 4 maybe more rivets....The tabs of post #91 also would allow deflection without lockup.my mental history data base, predates the use of the use of the AN eye bolt type hinge that does have a documented failure mode of twisting in flight and locking the control surface.
Instead of using one eyebolt/one forkbolt you could use three eyebolts. This arrangement is impossible to twist.This isn't a completely novel idea in the man carrying aircraft world and, in my mental history data base, predates the use of the use of the AN eye bolt type hinge that does have a documented failure mode of twisting in flight and locking the control surface.
You're right, I did have better luck, never noticed any binding or excessive force... and the Ultrastar has a rather short side stick. I only flew my buddy's Firestar once, and I don't recall any issues there either.Please trust me, absolutely do not use piano hinges on a light flexible structure. They do bind up under normal flight loads and make the ailerons unacceptably hard to move in flight.. Maybe Dana and others here who have flown the Kolb aircraft have had better luck than me with the piano hinges, and maybe the two Kolbs I flew were unusual, or built improperly.
You're right, I did have better luck, never noticed any binding or excessive force... and the Ultrastar has a rather short side stick. I only flew my buddy's Firestar once, and I don't recall any issues there either.
It is really important that the hinges are in line and square for lack of a better term...Also if the wing was not rigged properly or was loose and deflected much more that it should have, that would be another problem. You once posted about the bad flight you had, did you ever find out what the problem was?...Is your friend flying that machine?...There are many Kolbs flying if it was a design problem I would think there would be more noise about it.maybe the two Kolbs I flew were unusual, or built improperly.
Do you have a photo/drawing/link of these extrusions? I wasn't able to find them on Airdrome's website...
Both good observations. I'd forgotten about those extrusions. Of all the options so far they seem to me to be the best for their project - if they are available in the proper tube size.
Sorry, could you send a screenshot of the exact beam you're referring to? I couldn't find a brown beam so it's probably just my computer's crappy display and low res screenshots that are messing things up. If it's easier, you can view/copy/download the full 3D model from our public Onshape document. We were thinking of using honeycomb aluminum paneling for any floor panels that may be stepped on or have control mechanisms mounted to. Out of curiosity, what would adding a full X to the bottom of the cabin do that a single diagonal beam wouldn't? It would add some rigidity and ensure that one beam is always in compression but our initial calculations suggest that the 1x0.035" 6061 aluminum tubing is already plenty strong in compression or tension.I love what you’re doing. From a crashworthy standpoint I’d like to see you end the (brown) upper tube one junction further aft. That might be another reason to consider turning the triangle over. You might need more triangulation in the forward cockpit area and perhaps an “X” arrangement on the cockpit floor. Keep us informed of your progress.