[whd721]

I am finally starting to assemble my RV9A Tip-up project.

I finished the tip-up canopy six months or so ago and removed it for storage while I installed the wiring, panel, engine and FWF.

Now, when I reinstalled the canopy it appears to have been "tweaked". When it is installed, it has raised about 1/4" from the hinge outboard along the pilot side. The hinges and the rear latch both work and the canopy raises and lower smoothly, but has a 1/4" gap at the front corner and along the pilot side to near the rear latch.

I assume something is "bent", but so far can not see where the problem is and what should be unbent. I fear making the problem much worse with attempted corrections.

I am hoping someone has experienced this before or has built enough tip-ups to be an "expert" and to give me some guidance with this problem.

The project is in Sherwood, OR south of Portland.



Any advice or guidance will be appreciated.

 

[scard]

I'm guessing the front top skin wasn't riveted when you fit the canopy?

 

[whd721]

The front skin was not riveted on. It still is not.

I intend to move from my garage to the hangar in a week or so. I have tried to build as much as possible at home, before moving to the hangar 22 miles away.

I plan to install the nose gear when I move into the hangar, then the exhaust system, SCAT tubing and final engine connections, then the front skin.

Now AS soon as I am in the hangar I will assemble the entire RV9A to verify nothing else has moved.

Thanks

 

[BillL]

Hmmmmm, I have not glassed on the canopy to my frame for just such possibilities.

If yours is complete with all rivets and canopy glassed and screwed on, then I would be very surprised it got bent.

Are you talking about just the gap from the frame down to the longeron? Is there a gap also across the top? Progressive?

Has the hinge point moved up?

Sorry, more questions then answers.

 

[bruceh]

My tip up always seemed to fit differently every time I had it on and off.

Assuming that you had the front top skin clecoed in place when you drilled the hinge location?

A 1/4" gap would seem pretty large in this case. I see more like 1/16" max in the fit of mine during repeated fittings.

Is the canopy bubble screwed on to the frame?

 

[scard]

This is quite common to see on tipups, and it is going to drastically change again on you when you rivet that front top skin. For the better or worse is a poo shoot. I agree that .25" change from the last fit-up to later does seem like a lot. It also changes shape at temperature extremes too.
The front skin height from the hinge outboard is the big struggle with most. Mine came out pretty good, but some others eventually accept it for what it is and move on. I think next time I do one of the side by side tipups (probably never), I'll find a way not to drill the final large bushing hole until the front skin is riveted and all of the entire rest of the canopy is complete with plastic attached and fairing in place. Sorry, short on advise. I do wish Vans would give us more material to work with on those pre-cut canopy hinge ears. I would rather the plans say "trim to fit" than them deliver what they think should be the near final size/shape of the hinge arm that almost always ends up on the very edge of hole/edge tolerance. Sounds like maybe a scratch build of some sort is in my future .

 

[KRviator]

I'm just beyond this point and am pulling what little hair I have left out...

Despite making sure the bloody thing fitted nicely many times during the build, I now have a 3/16 gap between the F-771 deck and the canopy skin pretty much all the way around. At the 10 & 2 positions it was more like a 1/2" gap, but a ratchet strap and a bit of percussion persuasion evened it out.

IF I didn't know better I'd swear someone removed and re-drilled the mounting holes. The problem is the canopy skin was catching on the forward deck as it is, so trying to lower the canopy assembly will worsen this, unless I intend to file the canopy skin to an unacceptably large gap relative to the F771 deck.

I'm giving serious consideration to hiding this with a bit of fibreglass and just leaving it be for now.

 

[whd721]

Thanks for the comments.
I closely resemble KRviator, This is a test of perseverance.

http://kmmvphoto.smugmug.com/Airplanes/posts/i-8hjFnbT/0/M/IMG_3473-M.jpg

My gap as shown is from the pilot side hinge to the rear pilot side latch. The canopy was an OK fit when removed for storage now NOT SO MUCH.

Vans said not to worry about the canopy alignment until the front skin is on. However, when the front skin is on the canopy hinge pins are buried for life.

MY RV9A was a project, bought at about the Quick Build phase. The canopy frame was together and the hinge pins drilled. I thought about trashing the whole frame, but decided I could make it work. Now the Canopy is finished and the gap appears! OHHHH WELLLL!!

 

[burtj]

Mine did the same thing. It was a perfect fit, and then it wasn't. I came to curse the %$#@ shape-shifter, as even the changes weren't consistent with each removal. In the end, I wound up doing a small fillet of epoxy/West Marine XXX (can't remember the number) structural filler on the forward skin. It extends about 6" out from the gap, tapering to zero thickness. With paint, you can't even tell it's there, and it looks like the builder was a real rock star, not some hack making it up as he went along

Burt

 

[whd721]

Thanks KRviator and Burtj for sharing your experiences. There may be some more fiberglass in my future.
Vans believes that until F-771 the forward skin is on, things will change in the fit.

I fit the canopy then removed it and rolled the fuselage 90 degrees to install the panel and wiring runs. That may have caused my issues. Who Knows?

Thanks again.

 

[paul mosher]

chill

Don't get too anal. After reading about the dreaded tip up build I expected the worse. It wasn't that tough of a job.

 

[Rupester]

I certainly understand your frustration ... I think ALL of us tip-up builders do. I was horrifically discouraged at that point, but pressed on regardless. Once everything was done, my canopy clearances/gaps turned out wonderfully. I did NOT have that expectation a year or two prior.

There comes a point where you just say, "This is the way it is; I can make later cosmetic improvements with micro/Bondo."

 

[KRviator]

So...in following up this debacle, I once again channelled my "you're not building a show-plane" logic and simply added a fillet of micro to blend the canopy skirt into the forward deck.

To do this, you'll need your favourite epoxy resin, in my case I use West Systems 105 resin and 206 slow hardener and a smallish bag of 411 microspheres.

First off, get some of your favourite duct tape and tape the forward edge of the canopy skirt. That way, you only have to lift the tape and any pieces of micro that have landed there will come away cleanly. I neglected to do this step and promptly wondered why I didn't when it came time to clean the excess micro up...

Mix up around 70ml of resin, add enough micro till you get little micro-mountains that don't fall over when you lift your stirrer out of the mixing cup. Drop dollops of your stiff micro into the gap and, using a micro-free popsicle stick held on the forward deck and canopy skirt, smooth it down. 70ml will just about cover from the longeron to the centreline of the plane, so you'll need another cup for the other side.

Don't worry about streak lines too much as you'll hit this with sandpaper later, but smoother here does make it easier there.

Buuutttt.....

You have 20 mins working time with the slow hardener -so don't worry too much about getting a perfect photo....Oh...And ignore the small crease in the canopy skirt, too. I wondered if I could nudge it down to the F771 to better bridge the gap. Turns out you can't... So I might add a smidgen of micro here too..

From this...

To this. TA DAAA! And that's before the sanding part too.

 

[whd721]

Thanks for posting the photos,

I have decided to defer my canopy fit till later.

I am assembling the plane to find any other major problems, then will go back to the canopy. Your fix sounds good to me.

I built the project in my garage then moved to the hangar a week ago. Now I am trying to tighten the formation of all my parts.