Oz build SS7

[rosslr]

Thanks for your thoughts Alan and AF. I have looked at this pretty closely and have decided to stitch right up to the front spar top and bottom. the bottom was straight forward. The top required drilling in through the fabric and fibreglass using first a 2mm and then a 3mm drill bit - this resulted in a small raised section (fabric I think) around each hole. I used a clean pointed tip soldering iron to quickly push into each hole and this resulted in a nice neat flush hole. After a little experimenting, I realised that I could not use the running stitching method if starting from the top side of the wind as it was not possible to push the needle forward to the next hole in the fibreglass LLE ( without damaging it as it is not as flexible as the fabric). Instead, I have turned the wing over and it possible to run the lacing the width of the LLE. I have found it is easier to maintain a good, consistent tension on the lacing using the 'running' lacing method. Anyway, I will keep going tomorroe and post some photos.

cheers

Ross
Mt Beauty, Victoria
OZ

[rosslr]

I have finished the wing lacing on the left wing now. As posted earlier, I used 2.5" spacing for the whole wing and laced right up to the front spar, including the LLE. We have one of the young guys (Bayu) visiting from the village where we have a house in Bali, so provided a bit of work experience!

That's it for three weeks now - have to go to WA to work and then up to Bali for a little visit!

cheers for now

Ross
Mt Beauty, Victoria
OZ

[Planesmaker]

Hi Ross and Gayle, I have only just joined this fox forum, just finished reading your posts, you have certainly enjoyed yourself. Looks as though you (or actually Gayle) seems to have the fabricing in hand. Well done.
Amazing where help comes from when you start building a plane. Good community them plane builders! We will try and get down your way again on a nice day to see your progress. I haven't found anymore 914's yet. Regards Tom & Marsha

[rosslr]

Back into it today after a three week break away for work and sort-of-work up in Bali. It has turned cold here now, but nothing like some of you guys get up North! I got stuck in to the underside of the wing today and completed all the fore/aft tapes and reinforcing patches for the protuberances. I only have a week before I have to go away again but hope to get this wing finished up to the spray coats of the Poly Brush and then get the rack built for the remote compass unit of the MGL X-treme unit. As mentioned before, I used 2" stitching and drilled and stitched the LLE so the stitching goes right to the leading edge. It is good to be back into it!
Ross
Mt Beauty, Vic
Oz

[rosslr]

Good to have you on the site Tom! With your experience at building and repairing planes you will be very welcome. For others reading, Tom lives about an hours flight from us and flies a Jabiru with a 914 fitted ( that he rebuilt). He also repairs planes. It is always good to see Tom fly in with his wife and 3 young kids strapped in the rear seats!

I expect you will have me a 914 before long Tom!

cheers to Marsha and kids

ross
Mt Beauty, Vic
OZ

[jrevens]

That looks good, Ross!
Has anyone else done lacing over the LLE? One other question - have any of you guys with the LLE glued the fabric over the entire surface, or just the forward area? Sorry to hijack your thread, Ross.

[HighWing]

That looks good, Ross!
...have any of you guys with the LLE glued the fabric over the entire surface, or just the forward area? Sorry to hijack your thread, Ross.

Polyfiber:
Typically with a hard flat surface - fuel tank for example - apply a couple of coats of Poly brush on the hard surface first then cover. The first brush coat of Polybrush will soften the coating on the hard undersurface and create a bond. My "poor man's" aluminum leading edge was done that way. I did not drill and riblace, but did continue the finish tapes to the forward area. Others I have talked to terminated the tapes at the aft edge of the leading edge. Since Harry Riblett says that the most forward five or six inches are the most critical on his airfoil, I would suspect any possibility of ballooning there would be detrimental to performance. Keep in mind that the mass of the leading edge will absorb some of the heat applied to the fabric acting as a heat sink, it is sometimes difficult to get the fabric to the desired shrink temperature so bonding to the leading edge would help compensate for that.

Then this thought occurred to me. Since the LLE is composite, I don't know how the application of heat, as in the Oratek process, to initiate the bonding would affect the thin composite structure, you might want to talk to the factory for advice on that. I do recall one builder who drilled the LLE and rib laced to the spar. Maybe it was to eliminate the need for the high heat necessary to achieve the bond.

[mr bill]

I wrapped the bottom fabric up and around the front to the top trailing edge of the LLE. I bonded the fabric there and at the rib locations. Other than adhesive, no attachment to the LLE. Rib and false rib tapes stopped at the LLE. I used the Stewart System adhesive.

[jrevens]

[quote=HighWing;...
Then this thought occurred to me. Since the LLE is composite, I don't know how the application of heat, as in the Oratek process, to initiate the bonding would affect the thin composite structure, you might want to talk to the factory for advice on that. I do recall one builder who drilled the LLE and rib laced to the spar. Maybe it was to eliminate the need for the high heat necessary to achieve the bond.[/quote]

The necessary temperature for Oratex should not be a problem. You can set & activate the glue at 70 to 90 deg. C - less than 200 deg. F.

[rosslr]

Morning guys,
Interesting to see a few different approaches to this. John, I was cautious of gluing the LLE too much as the wing needs to flex. I remember flying with Paul L and watching the flex as we were flying. My thinking was/is that the LLE provides a solid fore/aft surface for the airflow and that the fabric, once shrunk, will hold it in position. As for the stitching in the area of the LLE, my thinking was primarily to stitch the lower surface as far forward as possible - aesthetics on the top was a secondary consideration. I would note a few other things about the LLE - I applied a little too much heat in one spot and the fibreglass sagged a little in that spot (about the size of an iron) - nothing structural, but a noticeable 'dish where the iron was that left the fabric in that spot about 2-3mm proud of the f/g. Not a problem really as the heat shrunk fabric takes its own shape and looks fine. Another, observation. As we have moved from a hot summer to winter, I have noticed that the LLE on the wing yet to be covered has rippled a bit - I will post a pick of this tonight. I am not sure what ( if anything) I am going to do about this yet. I will experiment to see if the fabric, when shrunk, will pull it all back into a smooth surface. I guess what I am assuming is that the LLE is subject to a little bit of expansion and contraction as a result of large temp changes ( 40 c plus in summer and 0c minus in winter). Anyone else noticed this? Thoughts/opinions welcomed.

cheers

ross
Mt Beauty, Vic
OZ