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Tip-up canopy frame: It's robbing my gumption

LettersFromFlyoverCountry

LettersFromFlyoverCountry

Well Known Member
I need help from you engineering types out there -- especially you Minnesota engineering types (and you know who you are). I'm at wit's end on the canopy frame.

Last week, I installed the tip-up canopy frame struts on the project and although my old pal Kevin Faris warned me it would pull the frame forward, I was shocked by how much it pulled the frame forward. My nice 1/4" gap between the rear channel and the rollbar was now more than 1/2". And everything was slamming into the front skin, inviting a disaster of another type. That 3/32" gap I filed in per the instructions months ago? I needn't have bothered.

I wasn't sure what to do. My e-mail to Van's support for guidance went unanswered. But a gentleman of the Yahoogroup list mentioned the reinforcing kit. When I looked, to my surprise, I hadn't riveted in the reinforcing kit yet. I thought I had but I had removed them for painting and I'd never gotten to them.

I had previously fit things with the reinforcing kit clecoed in place and while things weren't perfect -- this is the canopy frame for a Van's aircraft, after all -- they were acceptable. And while the left side was a little higher than I would've liked (because I slightly misdrilled the left hinge ear way back when), the right side has been pretty darned good through all of the fitting and cutting and bending and drilling and riveting since I started this part of the project last February.

So imagine my surprise when I refit the canopy frame yesterday afternoon (I'd gotten frustrated when Tom Brady through an interception during the Patriots-Chargers game that I shut the game off and went out to the garage where things, I thought, would be far less frustrating. Wrong!).

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The whole right side suddenly has lifted up. Please see the post I stuck up today at Letters from Flyover Country for a description and pictures. And if anyone is in the St. Paul area, I could really use some help dealing with this.
 
The canopy frame is pretty flimzy without the plexi. I put the struts on after finishing the frame including the plexi. It may be more of a problem that the front skin isn't riveted in place yet (I'll bet yours isn't either) but mine pushes forward when I close it. I'm using the struts only to hold it open and don't close the canopy at least for now. Once my panel is in I'll finish the skin off and install the rear window. I would avoid using the struts in the closed position until then. I don't know what to say about the gap. Maybe check the center to center distance of the struts attach points and check the canopy hinge attach points, maybe it got strained on that side.
 
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Other than pulling everything forward, the struts aren't the problem. Something happened in installing the reinforcing kit and I'm just trying to come up with a logical checklist to determine what that might be.

If anyone is looking to start an RV business, by the way, I'd have paid big bucks for a pre-built frame and canopy. :D
 
Bob,

This is not exactly advice but rather my experience. My canopy frame moved whenever I breathed. Even when I drove the rivets for the boot cowl, the last piece of skin on the airplane, the fit between the canopy and rear window changed. I still haven?t figured that out but in this case it helped the fit.

As for getting frustrated over the Pats, now you are just whining ;)
 
McFly said:
Bob,
As for getting frustrated over the Pats, now you are just whining ;)
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Real Boston fans always assume disaster is imminent. The boastful ones are newcomers.

Re: the canopy, I suppose in the long run, perhaps, it may not be a big deal. I can still pull the frame down manually and once I lock it, it fits OK. Then perhaps the weight of the plexi won't hurt things at all.

But, still, I kind of think if there's a problem ... the best route here is to try to fix it. If there's a twist in the frame, especially considering the plexi has already been drilled to the frame when things were right, it's going to stress the plexi -- I think -- when I close the canopy tight. Given these cold temperatures up in these parts, that could be a disaster.

I'm going to take that instrument pan off and see if that reveals anything.
 
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Bob if your can-o-pee is high on one side you can fill the hole on the offending hinge with JB Weld. Let it cure well and re-drill the hole. There is plenty of strength there for trouble free operation. Yes the can-o-pees can shift and it is frustrating.
 
Bob,
I just finished my -9A T/U canopy and I can attest to your frustration!! Even with everything bolted up I'm surprised how flexible the entire structure is. When I hooked up my struts (last step) nothing fit right! No wonder these things crack down the road!!!:(

I found that at least clecoing in place the forward most skin provided enough forward structure rigidity that at least the latching lugs would once again go into the holes!! Those stuts impose an incredible force on the canopy position. At this point, I think it's completely fruitless to mess with final canopy fit until that top forward (firewall facing) skin is riveted in place.
 
I'd be inclined, I suppose, just to shrug and worry about it later if this had been something that has been consistent throughout. But I'm too curious as to what exactly is causing the problem. From the process of elimination I know it's not the struts. I'll know a bit more when I get the panel out of there.

Right now I'm leaning toward drilling out the two farthest outboard holes (I guess, now that I think of it, it's four) from the rear of the right side reinforcing plate and then giving the whole thing a twist...trying to bend that rear tube up a little bit (to clear the panel angle) and then bending it inboard a bit.

But I'm trying not to do too much drilling out of rivets until I figure out what all the possibilities are of where it went wrong.

To me this is like flying and running into some trouble. First step is to undo the last thing I did.

Still, it's friggin' puzzling. If it is the reinforcement kit that's causing the problem, it's hard to believe you'd get THAT much twist by riveting something that had been clecoed in place without revealing a problem.

I sure could use someone to actually come to the garage and eyeball this thing, 'cuz it has so far escaped my feeble attempts.
 
From a slider guy...

Okay here's some input from a slider builder (I'm not even sure which parts in your photos are the "reinforcing kit" parts) so I'm just shooting in the dark here. But I can relate to your aggravation and I really want to help.

You are on to something here:
To me this is like flying and running into some trouble. First step is to undo the last thing I did.
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That is always a good plan: "everything was okay until I..."
It was suggested earlier that the problem might be exacerbated by the struts. I'd take those off first. Just to rule that out. It's easier, less time consuming and less frustrating than drilling out rivets.

I think I'd hold off on drilling any rivets until you get the plexi fit and see what happens with that on. My canopy had to be pulled in by an inche or 2 to make it contact the sides of the slider frame and I think that's normal. And when I attached the plexi (I glued mine) I made braces that pulled the sides of the whole assembly in ~3/8" so that it would be right when it sprung back out and should have made it more. I think that a fair amount of flexing of the plexi is normal.

Geez, Bob I hope you get this figured out. The canopy was the hardest part of the plane so far for me and I'm really glad it's done (except for the wind screen).

Keep us posted.
 
Bob, I think you need to have Tom Berge have a look - he's done two tip ups. Email me if you need his phone #. Aren't canopies fun?:eek:
 
Quite a few times in my build something came up that just seemed overwhelming. I found the worst thing, for me, was to just forge ahead at that point.

My advice is to take a little time off. Sometimes just doing that revealed what the source of a problem was or what the solution was. The answer for me often comes in the shower.
 
Bob Collins said:
If anyone is looking to start an RV business, by the way, I'd have paid big bucks for a pre-built frame and canopy. :D
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I've thought about building and selling frames made of fiberglass. The problem I see with doing that is that from plane to plane that areas dimension can be somewhat different. So a pre built structure may not work out very well. That and I don't think anyone would want to pay what I'd have to ask for it.
 
Update: I have located the culprit. I took the instrument panel off and, voila! The side rails rested (roughly) where they're supposed to.

So what's causing the problem? The weldment that attaches at the rear tube on the right side is hitting the top of the instrument panel, thus propping it up slighly.

You can click on this image to see a larger one:



So, what to do now? I'm thinking of cutting the angle that reinforces the panel in that spot and filing the top of the panel in that, perhaps, 1/2" to 1" swath to allow the weldment to nest and the canopy frame to come down properly. Does anyone see a problem with that solution?

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As to the problem of the struts pulling the canopy frame too far forward, I'm completely digging this tip from Mark Phillips in Tennessee. He created a "stop" to keep the frame from going past a certain point. This seems like a fabulous idea.

Read about it here.
 
Norman CYYJ said:
Now that is interesting, why is it interfering with the instrument panel. Never had that problem before.
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This piece snapped off almost as soon as it arrived in the finishing kit. I don't know why, bad weld, I guess. So I took it to a guy near here and he welded it back on. It's possible, I suppose, that he put it just a tad lower when it was rewelded back onto the tube.

Just a theory. But someone said earlier they'd seen cases where a rivethead from the line of the bracket-to-skin rivets interfered. Perhaps it's THAT close to begin with.
 
Bob,
I found my tipup is rubbing in the same spot. Will fix that when I get around to it. I found that the tipup is something that I work on when I feel up to it. I've been on the tipup for about 2 months and have the canopy cut out and the frame all done. Seems quick, but I'm bummed by the project as well. This is what I've been doing, something else in between. Working on the landing gear, working on the panel, set the seats in, bolted in the rudder pedals. When I feel like working on the tipup, I do it. If I get frustrated, I work on something else. I thought that cutting out the panel would be a pain, but I actually like it and it's coming out real nice. I was going to do the prepunched thing on the panel until I added up the cost of the guages. Now I have a prepunched panel for a pattern for the non prepunched panel. In a way it's been very useful. I think if I had to do it again I would want a prepunched panel just for setting out the panel, was very easy and made putting the different things on my panel very neat and straight. Oh and the D180 is very cool.
 
I'm guessing it's because I am not quite there yet...but I don't get where this jam stop is located...

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:confused::confused:
 
Chad,

Its right in front of where the forward most canopy deck meets the subpanel right above the longeron. The stop bolt is going thru the subpanel and contacting the lower front corners of the canopy frame.
 
I am also following this thread, good info for us planning tippers. These stops look like a great idea due to the force of the struts pushing on the frame!!!
 
Brantel said:
I am also following this thread, good info for us planning tippers.
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Only if you're a cursed and crappy builder. :D The odds of anyone encountering the stuff I tend to encounter on a regular basis seem remarkably small.

By the way, I still haven't been able to find John McD who posted the treatise on his frustration with the tip-up a few years ago (mentioned it in the blog). I'm dying to know if he survived the pain.
 
Bob Collins said:
Only if you're a cursed and crappy builder. :D The odds of anyone encountering the stuff I tend to encounter on a regular basis seem remarkably small.
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HA!

You just whine more! Kidding Bob, just kidding. I've had problems with my canopy install inspite of being warned it would be a bear. Mine is a different problem than yours, though.
 
If I had read this thread a year or two ago, I might have built a slider.

No, instead I'm right there with you all, drowning in my bitter tears over the canopy work. I'm in the cracked canopy club - a membership I earned on Christmas. Decided to wait till warmer weather to try again with a new canopy. Now I'm working on fwf and installing doodads like antennas and servos.
 
Yeah, this is the type of stuff I'm doing until it gets to be in the 90s again.

BTW, I ended up dropping the instrument panel by 1/8" to get the frame to close properly. I was able to use the existing outboard holes (for the screws to the nutplates in the angle that's riveted on the side deck). But I had to drill new holes where it attaches to the ribs.

Moving on...
 
Bob,
I finally got the gumption to work on my canopy again over the weekend. I finished the strut mounts that attatch to the aft side, fun time putting in the mounting bolts, ended up taking about 30 seconds on each side with the use of some vasaline. But, back to the big thing. I had a problem with the canopy closing all the way, I didn't want to do anything with the panel, so I looked and pondered and what I ended up doing was to bend the tubing where you put in the pop rivets along the edge of the panel. I put a hand in the center and used the other hand to pull the sides down, this will pull the outer sides in, so when done you move the center bracing (your hand) to the bend in the canopy and pull the sides back out. My canopy now sits down perfect and the sides look good to.
 
Oh, one more tip for those not yet into your tipup. I would leave the drilling of your hinge until you have the skin revited on your canopy. Unfortunatly mine changed after I revited my skin on and had to redue the hinge alignment. what a pain. I don't see any reason why you would have to drill the hinge before putting on the skin.
 
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