Sonex Canopy
Posted: Sat Nov 07, 2015 7:21 am
by rfidler
I recently inspected a Sonex under construction about 95% completed. Builder has done an excellent job. During my inspection, I became focused on the canopy design. The more I looked, the more I became skeptical about the frame design, rigidity, and fit and finish. When I finished my review, my conclusion was the whole canopy design of the Sonex is feable at best, especially the frame where the aft canopy section mates with the forward section. The Sonex frame, a bent piece of tubing, how crude.
Are any other builders out there that have improved the canopy design and are flying a Sonex with this improved design. My thoughts would be to build one piece hinged canopy design with a carbon fiber frame similar to European Glider designs. These canopy designs have the canopy supported in a carbon fiber frame around the complete profile and this canopy and frame sets into a frame attached to the aircraft. Yes, it would weigh a few more lbs than the current design, but would be far more durable.
What do the current builders and owners of Sonex aircraft feel about the Sonex Canopy design?
Sonex Canopy
Posted: Sat Nov 07, 2015 9:22 am
by Sonex1517
Hi
Since you didn’t introduce yourself, and I see you are a new member, I am curious why you posted this…?
Are you a technical counselor? Did you design a better canopy?
Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 9:48 am
by XenosN42
I have built two Sonex, a XENOS and OneX. I don’t find the canopy design to be feable (sic) and have had no problems after 4 years and over 200 hours of flight.
However, if you do your research you’ll find a few alternative canopy designs, mostly those that slide back instead of opening to the side.
– Michael
XENOS; N42XE; 180 hours - FOR SALE
OneX; N169XE; 30 hours & counting
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 10:35 am
by Bryan Cotton
Bob,
I don’t think it is a terribly uncommon design. My Hummelbird is similar. Anything can be improved upon, of course at a cost of time and money. I have a bunch of time in the ASK-21. It has an awesome canopy. Not sure I need that for my Waiex though! When my old club broke one it was megabucks to replace. Personally I am happy with the stock design.
Sonex Canopy
Posted: Sat Nov 07, 2015 11:41 am
by Sonex1517
Because I sounded stupid on my last post, I want to re state my response. I should have had more coffee or just shut up.
Others have pointed out there are alternatives. The Sonex canopy keeps with the design and philosophy of the airplanes. Simple and light.
Could it be improved on? This is subjective, but it is experimental aviation and the builder or owner can certainly pursue other options. There are trade offs though, specifically weight and complexity. This is not an airplane meant to be heavy nor complex. It is easy to do both, but the outcome may reduce the performance.
If you intend on designing something different just be certain it is safe.
My apologies for my earlier gruff response.
An introduction does go a long way in helping us understand your experience, and what interests you…
Robbie Culver
Sonex 1517
Chicagoland
First flight 10/10/2015
N1517S
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 3:26 pm
by rfidler
Sonex1517 wrote:Hi
Since you didn’t introduce yourself, and I see you are a new member, I am curious why you posted this…?
Are you a technical counselor? Did you design a better canopy?
Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved
I am a longtime pilot 40 years plus, over 3000 hours, owned 4 powered aircraft, 2 gliders. Over the last 15 years, almost all of my time is in gliders, competition and cross county without a motor. I still enjoy powered aircraft and currently looking at small experimental. I like the Sonex for a simple design, good performance, popular with EAA builders. My comments about the canopy are from looking at a Sonex. It looks feeble and also flimsy. I posted these comments because those are questions about what do other pilots think that own the aircraft. I am not a technical counselor. It is required to be a technical counselor to make a comment about what I think of the design? Get real dude.
Sonex Canopy
Posted: Sat Nov 07, 2015 3:39 pm
by Sonex1517
I deserved that.
Welcome to the forum.
Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 5:17 pm
by N111YX
The Sonex canopy is all it needs to be. It can withstand 200+ mile per hour speeds and all the rain and G’s on can put on it. Fit and finish is in the hands of the builder. Does it appear flimsy? Perhaps when it’s open. I only care when I’m flying.
I don’t look at it as crude but rather as light as possible, easy enough for the average builder to construct, and cheap enough to replace. It’s brilliantly engineered for the what the Sonex aircraft mission is supposed to be.
If we all had carbon fiber frames made, we’d probably all regret not going for the Lancair.
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 6:13 pm
by kmacht
I guess I will be the first to agree with the original post. I think the canopy frame is one of the weaker parts of the sonex airframe design. Yes, it does what it has to but in my opinion it is very flimsy, can’t be opened up in a brisk wind without risking breaking the canopy, and is not in the least bit waterproof. I would love to see someone come out with a better design.
Keith
#554
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 7:04 pm
by N111YX
Alternative designs are available at the expense of weight and money. Contact the American Sonex Association for plans.
Re: Sonex Canopy
Posted: Sat Nov 07, 2015 7:20 pm
by mike.smith
kmacht wrote:I guess I will be the first to agree with the original post. I think the canopy frame is one of the weaker parts of the sonex airframe design. Yes, it does what it has to but in my opinion it is very flimsy, can’t be opened up in a brisk wind without risking breaking the canopy, and is not in the least bit waterproof. I would love to see someone come out with a better design.
Keith
#554
As someone who is about to build their second canopy (broke coming back from OSH), I have to agree. The Sonex canopy is what it is, and it does work just fine when it’s closed and locked. But although I would not call it feeble, it is far from robust. I added two extra diagonal braces to the rear canopy frame, and that stiffened it up quite a bit. If anyone were to ask, I would recommend adding bracing to reduce the severe flexing that can happen with the rear of the canopy.
One thing you never do with a Sonex canopy: leave it open! All it takes is a gust of wind or the prop wash from a passing plane, and you’ll probably be building another one. I never leave mine open, even on a no-wind day.
Just my opinion.
Re: Sonex Canopy
Posted: Sun Nov 08, 2015 12:13 pm
by ihab
rfidler wrote:These canopy designs have the canopy supported in a carbon fiber frame around the complete profile and this canopy and frame sets into a frame attached to the aircraft.
Basically, if you create a composite insert that rivets and/or glues to the entire boundary of the existing metal airframe, from the firewall in the front all the way to the start of the turtledeck, you can build whatever sort of doors, hinges, and whatever else you want into it. This would essentially be just like the RV-10 composite cabin. It would be an interesting project to try – get a Sonex airframe, develop your idea, and see where it fits in terms of cost, complexity and weight. Then if things look good, get some tooling together, then start selling it as an aftermarket mod!
Ihab
Re: Sonex Canopy
Posted: Sun Nov 08, 2015 1:27 pm
by Bryan Cotton
There has been an interesting variety of responses, both pro and con for the stock canopy. Good discussion.
I have a funny story on the ASK21 canopy. One of my buddies back in NY was the chief pilot for our facility. He was my age, but all his time prior to Sikorsky he had been a Navy pilot. Flew and instructed in both fixed and rotary wing. At the Naval Test Pilot’s School in Pax River they even start cadets out in gliders. The first time I chucked him in the front of the ASK21 he slammed that canopy down like it was an F18. Well, probably more like a T34C but F18 sounds better. I nearly jumped out of my skin. Had to brief him on how to close the canopy. He thought our civvie stuff was flimsy.
Re: Sonex Canopy
Posted: Sun Nov 08, 2015 3:46 pm
by Rynoth
After installing the ASA swingback canopy I will give it a +1 for adding some rigidity and ease of opening, along with being safe to leave open. Although it lacks the cross bar across the aft arc of the canopy, the 3 swing arms add their own bit of rigidity to the shape, and the canopy is never subjected to forces that would tend to squeeze it inwards like the stock design does when opened.
Re: Sonex Canopy
Posted: Sun Nov 08, 2015 4:51 pm
by marsolgp
I’ll second that about the swing back canopy mod… I even taxi with mine full open. Only down side is I now have bugs to clean off the inside of the canopy. So if some one was looking for a more ‘rigid’ Sonex canopy, this ones already been engineered (mostly).
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 12:18 am
by phenry
I have to agree with original poster.
The design whilst light is also very flimsy and only encourages cracking.
I loved building my Waiex however I struggled with two components of the build, the cowl which apparently now comes ready to bolt straight on and the canopy.
Because of cracking I am currently working on a redesign of canopy which I hope will make it stronger, less flexible and eliminate the screws and rivets.
I would respectfully suggest considering the number of complaints (posted here) about cracking canopy’s are directly proportional the design rather than the materials.
Flame Away!
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 12:51 am
by rizzz
I wonder if you were to just rivet small triangular aluminium plates (maybe 0.060" thick) in the 4 corners to the aluminium tubing, whether it would stiffen things up a bit.
Wouldn’t look very good though…
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 9:06 am
by rfidler
Now I feel like I was not the only one who has reservations about the current design. I have a close soaring friend of mine who works on composite gliders and has been trained in Germany on sailplane repair. He can basically repair a glider that has been flown into trees and is in pieces and put it back together. There are numerous repaired gliders flying today that pilots have no reservations about his ability. He is totally capable of building a set of molds to layup a carbon fiber canopy frame, that would be one piece canopy assembly and hinged on the side very similar to numerous European composite gliders. I will have a discussion with him to get his input. I believe this improvement could really enhance the current Sonex design.
Keep tuned and thanks for all the great responses.
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 9:35 am
by DCASonex
Agree that a stiffer frame would be welcome, but a large part of the reason for the cracking is the manner in which the standard Sonex canopy if formed with curved lower sides that are then held to the flat frame. I have seen those crack both riveted per plans and bonded without rivets. Pressing the curved surfaces flat places the inside surface under tension. On all that I have seen cracked, the canopy tries to revert to its curved shape and slightly humped shape can be seen and felt between cracks with the cracks felt as valleys from the outside. Todd’s canopies are flat on the sides. This may very slightly reduce space inside, but I do not notice it, and my bonded Todd’s canopy is completing its 4th flying season with no cracks. Some have said the Todd’s canopies where heavier, but mine is same thickness as the original Sonex one. Looked at the swing-back design before building mine, but since I was building mine to carry two people in relative comfort, was concerned that the side arms eliminated the chance to provide side pockets, and slightly reduced width which might be a consideration for others as well.
David A. Sonex TD #1327, CAMit 3300
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 10:59 am
by rfidler
You refer to Todd’s Canopies. Could you define Todd’s Canopies because sorry, I have no clue.
Thanks
Re: Sonex Canopy
Posted: Mon Nov 09, 2015 12:19 pm
by Waiex 49
www.toddscanopies.com/sonex.html
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 1:00 am
by jmtraylor
As a member of the cracked canopy club, I am of the opinion that the canopy design is not all it could be and could be classified as “flimsy”, except when closed.
I had an idea for improvement after seeing the SubSonex at Sun-n-Fun this year. That canopy is quite different from all of the other designs (as it should be) but it seems the design could be applied to all of the others. It appears to be very rigid but just as lightweight and simple as the others. Unfortunately I didn’t get a second look at it before the end of the show.
Maybe a plans update/retrofit instruction sheet from Sonex? We did get a horizontal split cowl didn’t we?
Mark
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 8:20 am
by rfidler
You would think Sonex would be most happy to share the design of the SubSonex canopy with Sonex owners.
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 10:40 am
by DCASonex
There are two options for Todd’s canopies. The full windshield and canopy option as shown on their web sight, or canopy portion only. The shape of the windshield portion of Todd’s canopy is said to give better visibility and less distortion, but at the cost of a break in the smooth line of Sonex cowl to windshield, and giving up the higher impact resistance of the Lexan used on standard Sonex Windshield. I have the canopy portion only, and achieved a smooth line from windshield to turtle deck.
David A. Sonex TD #1327, CAMit 3300 (now 114 hrs on engine and all is good)
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 11:56 am
by andrewp
Hey, I just want to pitch in here:
I guess I have 70 hours on my Sonex. The canopy isn’t tough when open that is for sure, but when it is closed it is perfectly fine. I have the old material and I don’t have a crack in it. Our poor baby has been out on the ramp in NC rain for the past 2 weeks. With a cover on it, it has stood up ok. I found this weekend that I have managed to put a crack in the lexan (!), but my canopy is fine.
For those who are building and flying with a standard canopy, you are not bastard step children. Also one of the advantages of the flat wrap lexan is if it gets damaged, it is fairly simple and cheap to replace. You use the old one to match drill and trim a brand new sheet. I would not want to build a new canopy, granted. 
Anyway, the standard canopy has been A-Ok for me. I see a friend who is finishing his Waiex is using the swing back and it looks cool, but I am just enjoying flying my airplane and it hasn’t entered into my brain. I have other things I want to add on …
AP
#618
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 2:24 pm
by LarryEWaiex121
As a builder of the original plan design canopy, I feel fortunate at 4 yrs and 451 hrs to still have to original after all the posts to the contrary. I just about lost it in 26kt winds in Montague, CA. two years ago. Scared to get out of the plane. Took 3 tries.
I would be the first to agree that all things can be improved, but, at a cost of both your credit card and your useful load.
Jeremy Monnet and I had a number of spirited phone calls about the time I had maybe one year of experience with my Waiex.
We talked about what the kit should be in “my opinion” and what they offered.
My first order of preference was a bigger tailwheel. Well, Kip came along and sorted that one out. I bought one just as I was getting ready to fire up my tig welder and build one. Problem solved and it works great! Guess what morphed into the kit?
Bigger tail wheel.
Preference #2 was hydraulic brakes. Jeremy and me went round and round on this one. LOL I kept asking him his answer for those of us that “want to spend our money”? Obviously, they folded on that one and along came hydraulic brakes.
Point being is each one of those improvements came at both cost and weight.
I find the canopy frame to be way less important to me than either of the prior two. If enough people called, emailed and such, I doubt it would be very long before an up-graded canopy option would mysteriously show up. Along with plan pages to match.
No doubt a sweet carbon fiber frame could be built by the same guys that repair the Duo-Discus type sailplanes and it would be gorgeous and not a penny over $4,000.00. It all boils down to what you want. I feel Sonex has done a remarkable job of packaging a wonder plane for a moderate amount of money. And I am not a paid cheerleader but merely an owner with over 450 hrs that still gets giddy everytime I push the throttle forward on takeoff or do a slow roll just because I can.
Larry
Waiex121YX, Jab 3300 solid, 451 hrs., wanting for spring to come!
Re: Sonex Canopy
Posted: Tue Nov 10, 2015 4:23 pm
by andrewp
Larry, you and I are exactly on the same page. Check for the tail wheel (I have the new Sonex one) and I put in a crazy RV7 pedal/tracy obrien combo. That was what I cared about. Nothing against the canopy folk, but those things have been of more benefit to me!
BTW: You really have flown the sh*t out of that airplane. Good on ya!
Re: Sonex Canopy
Posted: Wed Nov 11, 2015 1:59 am
by tom0nex74
I used Stika-Flex to bond the canopy to the canopy frame, thereby eliminating screw holes, a common source of cracks. I found it easy to apply and it makes up for small imperfections between the frame and canopy. I keep the canopy closed and latched as much as possible on the ground…you just never know…Tom Ryan…0nex74
Re: Sonex Canopy
Posted: Wed Nov 11, 2015 11:22 am
by Fastcapy
-Removed-
Re: Sonex Canopy
Posted: Wed Nov 11, 2015 12:17 pm
by inventor
tom0nex74 wrote:I used Stika-Flex to bond the canopy to the canopy frame, thereby eliminating screw holes, a common source of cracks. I found it easy to apply and it makes up for small imperfections between the frame and canopy. I keep the canopy closed and latched as much as possible on the ground…you just never know…Tom Ryan…0nex74
I assume you mean “Sikaflex”, what version did you use?