SonexBuilders.net

So on my way back from OSH I stopped in Ohio and filled the tank, then pulled the plane to the side before I went inside for a pit stop. It was hot so I was going to leave the canopy open, but I have a PVC rod I use around the canopy cable to make sure the canopy doesn't flop around. As I was trying to put that over the cable, the nut on the end of the cable (where it attaches to the frame) popped off and the canopy swung all the way over until it hit the right wing. All that bending cracked the canopy along the horizontal rail, nearly from front to back. That nut is a nylon lock nut, but even so it unwound itself as the cable was twisted and untwisted every time the canopy was operated. I even checked this at my annual 2 months ago, but it undid itself in that short time.

When I built my rear frame I even added 2 extra diagonal supports with gussets and that helped stiffen the canopy considerably. It's on my Kitlog site if anyone wants to have a look. http://www.mykitlog.com/users/category. ... egory=7622

My canopy repair took me about 15 minutes. I actually didn't swear a lot. I just took it all in and got out the duct tape, which I always carry in my tool kit. Lots of duct tape inside and out worked. I can still fly it like this, but I'm going to have to build a new one sometime soon. So my question is this:

Since I always tell builders and passengers that the canopy is the weakest link in the aircraft, I'm taking this opportunity to think about other options, which include:
- New canopy just like the old one
- Todd's Canopy (just for the throw-over section; not the windscreen)
- ASA slide-back canopy (I hate adding weight, though)
- Re-engineer something myself with a more rigid frame

If you've done any of these I'd love to hear about how you like it. If you have other ideas I'd love to hear them as well.

If I do build a new canopy like the old one, I'm thinking I need to replace the two horizontal rails, and the steel angle pieces that connect the curved bows to the horizontal rails. Anyone with experience replacing a canopy, I'd like to hear your experience (a web log would be helpful if you have one).

Thanks,

My second canopy (first had optical defects in it) was a snap to cut and finish.
I also did a highly modified ASA swing back and love it. I think its worth the weight and complexity. And you will never worry about the wind catching it.
I'm not sure you can just do the Todds, throw-over section and not use the windshield. It is blown quite a bit higher that the stock one. Getting the lines to work would be very difficult.

On my side rails, I didn't rivet the side plates through the canopy to the horizontals. I used thin alum angle to squeeze the canopy to the horizontal rail and used machine screws from the bottom to secure the angle to the horizontal frame. So the only holes in the bottom edge are for the lock slides. It simply can't crack here. The rest of the canopy is held to the frame conventionally.

Mike

Don't overlook a small gas strut. They do a great job at holding the flimsy canopy safely open in windy conditions. 5 years now and no problems.

Steve
Sonex 892

I have the swing back canopy but not the one sold as a kit. On mine I used the supplied frame and canopy. For the latch I made the left per plans and the right side a mirror image. I can lock mine from the outside just as the original. I read someone on here say the ASA model does not have the ability to lock. I have left my canopy open at fly ins and at Oshkosh without problems. I can also taxi with it open when on hard surface. On hot days the canopy gets pushed open as soon as I hit the taxiway. Operating in grass when using a lot of power the canopy will lift at the back end with the heavy prop blast and slam down when the power is cut. The downside of a retrofit would be drilling the inboard right wing skins to install a wing walk. The additional weight for the whole change I would estimate as under 6 pounds, but the convenience of entering from either side and the ability to work under the panel easier along with better passenger loading was worth it to me. I did however do mine during the build which may have been easier than doing a retro fit.

After finding my Sonex canopy cracked the morning after it was bonded to frame, I got a Todd's No problems since. Weight is about the same, big difference is it lays flat against the fuselage sides and thus is not stressed when installed. The Sonex canopy does have a slight bulge on each side giving a fraction of an inch more inside width there. I have not missed that. I originally installed my windshield bow as high as the supplied Lexan for the windshield would allow. The Todd's canopy was supplied quite long, looks like it may have also worked on a tandem seat something-or-other. Picked an area that looked like its contour would match and it looks right at home, no break line at windshield junction. My frame is modified a bit to facilitate bonding with at least 1/8" gap between frame and Plexiglas, and modified latch. Details can be found on old Yahoo Sonex Builder's forum files section.

Looked at the swing back, but while many advantages, looked to me as if the inside hinge linkages stole a but of space and swept down across where I wanted side pockets, so did not go that route as intended it for some cross country flying with wife and maximum inside width and side pockets won out. Swing back definitely wins for the coolest look.

Caution on retrofit of swing back. it invites entry from both sides, but if you originally had side swing canopy, right wing likely does not have re-enforced wing walk area.

Going to check my canopy cable ends this morning. May be time to finally get to finding something better than that cable. Been on my to-do list too long.

David A. Sonex TD # 1327

sonex892 wrote:Mike

Don't overlook a small gas strut. They do a great job at holding the flimsy canopy safely open in windy conditions. 5 years now and no problems.

Steve
Sonex 892

I have a couple of small gas struts, with damping in both directions intending to experiment with fitting to canopy. However, have also read of folks damaging their canopies with bad installs. Do you have any photos or drawings on how you did yours and any specs on the strut ?

David A. Sonex TD # 1327

I installed the ASA canopy and will link below to my blog post about it. So far I really like the design but have yet to fly with it (still building.) It does not have a way to externally manipulate the latches without cutting into the fuselage sides, but I'm not yet convinced that it's necessary. There may be a way to secure the canopy from the outside using the 3rd middle arm but my brain is still working on that. I'm pretty big and was worried that the swing arms might reduce shoulder space, but so far that hasn't seemed to be an issue (my shoulders are above the swing arms with the canopy closed), and they sit relatively flush with the upper longerons.

This link is my experience installing the ASA swing back: http://www.rynoth.com/wordpress/waiex/2 ... ompletion/

DCASonex wrote:

sonex892 wrote:Mike

Don't overlook a small gas strut. They do a great job at holding the flimsy canopy safely open in windy conditions. 5 years now and no problems.

Steve
Sonex 892

I have a couple of small gas struts, with damping in both directions intending to experiment with fitting to canopy. However, have also read of folks damaging their canopies with bad installs. Do you have any photos or drawings on how you did yours and any specs on the strut ?

David A. Sonex TD # 1327

Hi David.

Extended 260mm / taken from bolt holes, centre to centre
Retracted 160mm
Piston / shaft 6mm
Cylinder OD 15mm

For the location of my turtledeck attachment bolt. Swing an arc 145mm from the corner where the turtledeck skin meets the side skin. Then from the turtledeck skin 45mm in to the arc.
Canopy attach bolt is about 85 mm in from the centre of the tube on the rear canopy arch

You may notice in the photo I use poor mans ball joints, which work fine. Long bolt with rubber fuel line as cushions. The angle stopper on the turtledeck holds the canopy in the correct position when closed. Hope this helps.

Steve
Sonex 892

mike.smith wrote:So on my way back from OSH I stopped in Ohio and filled the tank, then pulled the plane to the side before I went inside for a pit stop. It was hot so I was going to leave the canopy open, but I have a PVC rod I use around the canopy cable to make sure the canopy doesn't flop around. As I was trying to put that over the cable, the nut on the end of the cable (where it attaches to the frame) popped off and the canopy swung all the way over until it hit the right wing. All that bending cracked the canopy along the horizontal rail, nearly from front to back. That nut is a nylon lock nut, but even so it unwound itself as the cable was twisted and untwisted every time the canopy was operated. I even checked this at my annual 2 months ago, but it undid itself in that short time.

When I built my rear frame I even added 2 extra diagonal supports with gussets and that helped stiffen the canopy considerably. It's on my Kitlog site if anyone wants to have a look. http://www.mykitlog.com/users/category. ... egory=7622

My canopy repair took me about 15 minutes. I actually didn't swear a lot. I just took it all in and got out the duct tape, which I always carry in my tool kit. Lots of duct tape inside and out worked. I can still fly it like this, but I'm going to have to build a new one sometime soon. So my question is this:

Since I always tell builders and passengers that the canopy is the weakest link in the aircraft, I'm taking this opportunity to think about other options, which include:
- New canopy just like the old one
- Todd's Canopy (just for the throw-over section; not the windscreen)
- ASA slide-back canopy (I hate adding weight, though)
- Re-engineer something myself with a more rigid frame

If you've done any of these I'd love to hear about how you like it. If you have other ideas I'd love to hear them as well.

If I do build a new canopy like the old one, I'm thinking I need to replace the two horizontal rails, and the steel angle pieces that connect the curved bows to the horizontal rails. Anyone with experience replacing a canopy, I'd like to hear your experience (a web log would be helpful if you have one).

Thanks,

Hey Mike

I just had the same thing happen to me just a couple of weeks ago.. I went to open the canopy and the cable broke sending the canopy falling over on to the wing.. I thought for sure it was busted, but when I lifted it up it was still intact and no even a scratch on it.. Now, if this was a Sonex Canopy it would have been another story..

The Canopy I have on my Sonex is a Todd's Windshield/Canopy Combo.. If I was you I would go with Todd's for your replacement and you should do the windshield also.. Todd does offer just the Canopy, but the windshield gives you a whole lot more visibility out the front of the windshield.. When I take-off and land I am able to look straight forward.. The down fall with going that direction is that will most likely have to make new windshield and forward canopy bow.. Todd's Canopy set up about 1 1/2" higher then the Sonex Canopy does.. It is well worth the extra work.. If you have any other questions about it shoot me an e-mail.. sonex772@yahoo.com

Mike

Steve,

Thanks for the photo and specs. My struts are about 1/2" shorter stroke and did not care for the results when laid out on CAD. Will have to have another go at it.

David A. Sonex TD # 1327