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Canopy Woes

Scott Hersha

Well Known Member
I don’t like to complain, so I’m going to try to make it sound like I’m not complaining. There are several things that can set you back and discourage you when you are building, but there is one thing that is probably worse than most others……. a CRACK in your canopy, especially after you’ve spent 3 months making it fit, installing it, and then having it sit on your nearly completed airframe - looking down the tunnel at the light at the end. My RV6 slider frame was done, ready to fly.



I had finally gotten some help riveting on the remaining boot cowl rivets to enable the windshield to be installed, and I was ready to start finish work on that. I just installed the landing gear, so I’m ready for final wing attachment. Empennage is installed and I’m doing finishing glass work on those tips.

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Then today with some friends over, while bragging about my airplane and it’s progress, I notice this:

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This is a picture taken after I removed the canopy from the frame, with the help of those same friends who felt sorry for me because I was in shock. I would honestly sell this kit right now if I could recover my costs, and buy a Cessna. That’s how discouraged this is to me. I just talked to Jimmy Brod today, who is building my engine, and will deliver it next month. I optimistically thought I would be flying it to Sun-N-Fun. Not so sure now…..

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How about a convertible RV6? Works for me.
I talked to Jeff at Airplane Plastics after my canopy surgery, and he said he has an RV6 canopy in stock. Airplane Plastics is a 45 minute drive from me. He said I need to coordinate with Vans and purchase the new canopy from them. So I called Vans to do that. The part number for an RV6 canopy is C-601-1. Well, guess what - they don’t stock that part anymore and don’t sell it. They said I would need to special order it from Airplane Plastics and deal directly with them. Fine with me. The price for a new tipper canopy for an RV6, 7, or 9 is $1725. Yikes!! However, the RV6 slider part they show from Airplane Plastics is $450. I’m not sure I can work this out with them because Jeff told me I would need to deal directly with Vans. I’ll find out tomorrow. The removed broken canopy is in my SUV, headed for Tipp City, OH tomorrow. Jeff asked me to bring my broken part with me because he has the back half of an RV6 canopy that he cut off a windshield for and if it’s big enough, maybe I can use that - and he will trim it for me.
This isn’t the first time I’ve gone down this road. On my second RV8 I had a cracked canopy. I was just starting to work on it, and had set it on the canopy frame to try to figure out where to start trimming it. I walked over to my workbench to get a marker to mark where to start trimming. I heard a loud snap, and saw a crack that went almost completely across the back part of the plexiglass. Nothing had been drilled or cut yet, and this happened just sitting on the frame under it’s own weight. That was in July with my hangar door open on a 85* day. These things are delicate. This is my fourth RV build, and I’ve had two canopy cracks that I didn’t do anything to cause, and just happened pretty much on their own. This last one has been sitting finished on my under construction airframe for over two months, other than opening and closing the canopy occasionally when needed. I’m pretty paranoid about drilling holes in plexiglass, and will likely try to find my Larry Larsen posts about Sika Flex. Don’t know what else to do. I really like a sliding canopy best from an operational/user standpoint, but as far as building it - it is a very poor design.
 
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Well……. Here I go again. Most of the pictures I attached didn’t attach, and the two that did are upside down. Life sucks right now. I give up.
 
Sika

I know that feeling. Not on a canopy but elsewhere on the airplane. Let's just say I've drilled hundreds if not a thousand rivets.
All the links are on my blog. If I can be of any help, feel free to e-mail for my phone number.
http://wirejockrv7a.blogspot.com
You got this.
 
7 yrs ago I saw a neighbor that cracked a RV8 canopy upon releasing the canopy after carbon fibering the roll bar. I wondered if he was going to be able to recover but he did.
 
Keep pushing ahead.

Well……. Here I go again. Most of the pictures I attached didn’t attach, and the two that did are upside down. Life sucks right now. I give up.

It is not an emotional journey, just do it.

I say, Life is a dirt road to greener pastures. . . .You have to push through the mud bog section to get to the green fields and easy rolling.
 
Scott I feel for you! I can't be of much help with advise, I'm years away from this process. You may not remember me but you were nice enough to give me a ride in your 8 back in January of 2018 after I flew down from Cleveland. That got me going and I still remember that day and your beautiful airplane, I was sorry to hear of it's second prop strike after all you had been through.

Maybe we need to sacrifice a live chicken or something like they suggested in Bull Durham.... Something to get rid of your bad luck!

BTW, I never realized Airplane Plastics was in Tipp City! I grew up in the next town over in West Milton, small world.

Anyways the least I could do is fix your images, it's not much but hopefully you're having a better day today!


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FHkiJzn.jpg
 
Don't feel bad! This is just part of the experimental experience. I am a DAR, quite experienced, and when building my second RV-7, found that I did not match the roll bar radius closely enough, so into the trash went a painstakingly fabricated carbon fiber canopy surround, and plexiglass, about a $2,200 hickey! However, the second one turned out perfectly. Also threw away a plenum, did not allow enough clearance between the right front of the plenum and the top cowl when the engine torques during start up. Another bunch of $$$$, but now I proudly own a short field, IFR, cross country, aerobatic "show plane" , try getting that in a "spam can"! Hang in there, use EAA tech counselors, forums, etc. and I think you will elevate from the plateau you are on.

Regards,

DAR Gary
 
Scott I feel for you! I can't be of much help with advise, I'm years away from this process. You may not remember me but you were nice enough to give me a ride in your 8 back in January of 2018 after I flew down from Cleveland. That got me going and I still remember that day and your beautiful airplane, I was sorry to hear of it's second prop strike after all you had been through.

Maybe we need to sacrifice a live chicken or something like they suggested in Bull Durham.... Something to get rid of your bad luck!

BTW, I never realized Airplane Plastics was in Tipp City! I grew up in the next town over in West Milton, small world.

Anyways the least I could do is fix your images, it's not much but hopefully you're having a better day today!


4GjBx0S.jpg


FHkiJzn.jpg

Mike,
Thanks for fixing the pics. I don’t know why the first ones didn’t show, but it doesn’t matter. I’m done complaining. I will pick up a new canopy in the next day or two. Vans is trying to figure out how much to charge me since I will be picking it up myself, and might actually be able to just get the back/slider portion since airplane plastics has one that they removed the windshield on. The new canopies have a different part number and have some sort of UV protection - and are $1725 now. They are also tinted slightly different. I found out that the RV6, 7, & 9 canopies are identical, and the slider canopy and tip up are the same too. There is only one mold for all of those. I hope to be able to reuse my frame. If unable, I’ll order a new one from Vans ($500), and hopefully not have to wait too long.
Thanks for the reply.
 
Sorry to hijack but is there a difference between RV6 vs RV7 canopies? I did not think so just checking.

There have been many who cracked their canopy and there will be many more.... Use all the cautions and tips I am sure you know.... being winter make sure that bad expensive plastic is warm....
 
There is no difference between RV6, 7, or 9 canopies - slider or tip up. They are all the same and made on the same mold. The new ones have some sort of UV protection incorporated and the tint is slightly different. The one I will be picking up in the next couple of days is probably one of the new ones, and is being sold to me as a “second”. A second is one in which something is wrong with part of it, but the other part is still usable. In my case, they have one that they needed to cut out a windshield for, so the back, slider portion in my case, is still useable.
I fully understand the temperature issue, so I’ll only cut or drill on it at home after I’ve warmed it up significantly. I may be putting off finishing this part (for the second time) until later.
 
The UV protection used to be a special-order addition, as it was with my bubble. Apparently that's also now standard. Not familiar with the new tinting. Oh well. Interesting nonetheless.

Yeah, I was mildly sickened when I saw this thread pop up. :( Stuff like this is what makes me nervous about winter flying - not icing or anything else I can predict and plan around, but increased risk of canopy cracking. Even on the nice days two weekends ago, when I shut down for lunch in Urbana I could hear my bubble squeaking and flexing a bit in the sun. Let me know if I can help anywhere else in the build to try to help make up lost time. I'm hoping to be around during the week between Christmas and New Year's.
 
I am paranoid about cold cracking my canopy. I live in South Alabama close to the coast where temps are most always reasonable. I try to avoid anything less than about 40 degrees. I would love to fly the plane to visit my son in Massachusetts for Christmas. I thought about the possibilities... if it were to crack HERE at home it would be a disaster. If I flew it to cold climates far away from my home base in the winter months.... it would be an absolute catastrophe! Away from home, no tools, no hanger to do the job in, mega expensive and mega time. Just not worth it. I'll wait till spring. Interestingly, last year I was chatting with my son and he said he completely understood. He said the windshield in his work car had cracked just a couple days earlier from the cold!
 
I have a recent crack in my 7A slider windshield... stop drilled for now and 1 successful flight since I drilled and glued it. But I don't think it will last, so I am preparing myself mentally for replacing my windshield. This is not something I am looking forward to. :(
 
, trace

Your windshield is the ‘eaisier’ part to replace (nothing is easy). Remove the screws or rivets holding the windshield plexi in the roll bar, after separating the upper fiberglass coming from the plexi windshield with one of these:

https://www.grainger.com/product/20...VFcEzMnAzPxCpwoXD74aAirjEALw_wcB&gclsrc=aw.ds

Cut the fiberglass forward windshield fairing with a thin dremel type tool, and remove the cracked windshield. Save any of the removed fiberglass parts, because you may be able to reuse them.

Get a replacement RV7/6/9 replacement part from Airplane Plastics near Dayton, OH (not a terrible drive from AL). They have ‘seconds’ , or ‘blems’, that they are able to salvage a front section (or rear section) from. You will have to deal with Vans for this purchase because of contractural agreements, but this can all be handled over the phone on the day of purchase. You can also order this directly from Vans. Vans charges 60% of the full canopy price for a “blem”. Check the website. If you pick it up directly from Airplane Plastics, you’ll save the shipping charges that Vans has to pay to have this part from OH to OR, plus what they charge you to ship it to you from OR (plus possible delays). I’ve done this twice, of course I’m in Ohio, so easier for me. If you decide to go this route, bring your cracked canopy with you. Jeff Rogers (owner) might be able to place your damaged canopy in the mold, trace it, and trim your new replacement canopy to the size, or close to it, for what you need. He made mine slightly oversized so I could trim it with a belt sander to what I wanted.



Assuming you have a fiberglass
 
Sikaflex

I have had excellent results from Sikaflex on my RV-8A.
I make one other suggestion.
When reading accounts from other builders I saw numerous remarks about the flimsiness of the canopy after the windshield portion was removed. Several mentioned the need to retrim! It seems to me such twisting introduces stress loads which may be the cause of cracking. My solution was to sikaflex the canopy into the slider frame before removing the windshield portion. Three years and 350 hours of flight later…no cracks.
Good luck!
 
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I used Sika and my canopy still cracked. There was just enough tension in the front right corner that it cracked. I stop drilled, used the glue to try to repair, and even heated the corner to try to neutralize any remaining tension. I'm not flying yet so hoping it stays the 1 inch crack that it is.
 
Jimmy Brod engines

Sorry about your canopy.

Just thought I would give you some encouragement. Jimmy Brod built the 0360 A1A that I have on my RV7. During construction I converted it to an I0360 with dual EMAGs and a silverhawk fuel injection system. My engine has been flawless and now has about 350 hours. I had a couple of questions during conversion and phase I and he was very helpful and a pleasure to work with.
 
Canoparanoia

I'm also paranoid about cracking the canopy, so far so good, still part-way through trimming and fitting...

I noticed when trimming off the back edge that there is already some stress locked into the plexi, because the cut off piece splayed out while it was being trimmed. Not much than can be done about that, other than to support it carefully and immediately smooth the edges and de-burr holes and keep it at an even warm temperature.

Regarding temperature, I'm aiming to fit the plexiglas to the frame at a temperature that is in the middle of the expected range that the plane will operate in. This should help to minimise the differential expansion between the steel frame and the plexiglas.

There are a couple of places on the canopy frame where the tubes do not meet exactly, i.e. the middle "spine" where it meets both front and rear bows. This causes a gap between the plexi and the tube that would create a pressure point if it was to be riveted or screwed without any shimming.
 
There are a couple of places on the canopy frame where the tubes do not meet exactly, i.e. the middle "spine" where it meets both front and rear bows. This causes a gap between the plexi and the tube that would create a pressure point if it was to be riveted or screwed without any shimming.

I shimmed mine (many years ago) but if I was doing another one, I'd make a liquid shim using one of the epoxy putties. I think that would support the plexi better and would probably look better too after paint.
 
Shimming

I shimmed mine (many years ago) but if I was doing another one, I'd make a liquid shim using one of the epoxy putties. I think that would support the plexi better and would probably look better too after paint.

A liquid shim sounds like a good idea! It will allow the surfaces to be faired more evenly than with using an aluminum strip or washers.
 

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