It's not warm enough in the garage to work on the canopy, so I moved it back into the house until summer. I'll work on the firewall-forward stuff instead.
Too cold
November 26th, 2006Family visit
November 19th, 2006My family was in town visiting this weekend. My little brother Adam looked over every inch of the RV-7 project, and Al was nice enough to give him a demo flight in his RV-6A. He doesn't look like he enjoyed it at all…
While they were out I snapped some photos of this F4F Wildcat that was parked in the hangar. This particular airplane has a very interesting history.
After lunch, Adam helped me get the fuselage turned around. To do this we had to roll it out onto the driveway, which generated some very surprised looks from the people in the car that happened to drive past just then.
This orientation will make it a lot easier to work on the canopy and firewall-forward stuff. Just for grins we put the canopy bubble on top of the fuselage. It's going to need a lot trimming to make it fit well.
While my dad was in town, we used his Jeep to fetch a 4×8' sheet of 3/4" plywood from the hardware store. This will be my temporary working-on-the-canopy bench, since the canopy bubble is way too big to fit on my real workbenches.
I also bought another space heater. Next weekend I'll see if I can get the temperature in the garage up to the magic 70° mark so I can do some canopy trimming. If not, I guess I'll have to postpone any further work on the canopy until summer. Stay tuned…
Ordered engine
November 15th, 2006I ordered my engine from Mattituck today:
- TMX IO-360 with roller tappets
- ECI Titan cylinders with nickel carbide barrels
- 9:1 compression pistons
- Precision Airmotive Silverhawk fuel injection system
- Aluminum oil sump with forward facing induction
- Red Gold performance package (included with roller tappet option)
- One impulse-coupled Slick magneto
- One Lightspeed Plasma III electronic ignition
- Skytec high torque inline starter
Scheduled delivery is for the third week in January.
Canopy correspondence
November 15th, 2006Date: Mon, 13 Nov 2006 20:27:25 -0600 (CST)
From: Matt
To: Van's
Subject: RV-7 sliding canopy frameHi guys,
I've got the canopy frame on my RV-7 slider all fitted – I think – and I have a couple questions before I proceed:
1. I had an issue where the aftmost corner on the right side was rubbing/catching on the top skin when the canopy was slid back. I bent the right rear bow outward and it now clears the skin by a minimum of 1/16" on the right side, 1/8" on the left side. I am assuming that the spreading force of the canopy bubble will tend to increase this clearance, not diminish it, so I don't need to worry further. Is this a good assumption?
2. I got things arranged so that with the canopy tracks and slide rail screwed in place, the canopy will glide smoothly open with very light finger pressure. Then I slightly narrowed the front bow so that the rollers rub with moderate friction against the inboard faces of the tracks. My hope here is that if the plexiglass spreads it back out again, the rollers will wind up in the middle of the tracks and give smooth canopy operation. Is this worth doing or should I put it back to neutral and let things fall where they may?
thanks,
mcb
Date: Wed, 15 Nov 2006 07:50:14 -0800
From: Van's
To: Matt
Subject: Re: RV-7 sliding canopy frameThere will be some springback when the bubble is attached to the frame, but it is impossible to say how much on a given airplane.
Hmm. I was hoping for a more definitive answer. Luckily a friendly fellow on the VAF site offered this helpful response which seems to confirm my theory about the rollers.
Started fitting canopy frame
November 12th, 2006I iteratively cut about an eighth of an inch at a time off the bottom end of each canopy frame tube until they were the same length and the frame was aligned height-wise with the rollbar.
Viewed from the tail, the frame looks straight and the contour matches the rollbar. The canopy frame is supposed to sit higher due to the downward curvature of the canopy in that area.
My little offset-measuring tool shows the proper 1/16" spacing between the fuselage sides and both sides of the canopy frame at the front end:
…and the back end:
In this photo the rear bow of the frame is exactly 1/16" below the curvature of the aft top skin, but in the end I made the frame sit slightly above this level based on various pieces of advice I collected from various discussion archives. The rear canopy skirt will cover any mismatch and I think the fit will be easier with a little extra height back there.
Update: The above advice was not that great. I had to make my aft skirts out of fiberglass to cover the height difference. The plans really are correct here.
After trimming the canopy frame tubes, the front bow of the canopy sits the required 3/8" above the rollbar. I made this little measuring tool from more scrap plywood. Handy stuff.
I must have had the canopy on and off the airplane thirty times, trimming the tubes and making small adjustments to the shape by bending it in various ways. Once I was happy with the fit, I drilled the canopy tracks to the fuselage. The rearmost screw hole ends up very close to the longeron, so I had to be careful not to nick it. (that would be bad)
The plans call for you to use regular nuts and washers up under the canopy deck to attach the tracks to the fuselage. I decided that was an excellent recipe for frustration, since you can't see what you're doing up under there. So instead I made these nutplate strips out of some scrap material. I didn't invent this idea but I'm glad I used it because it was a snap to get the track screws in.
Fuzzy picture of the canopy tracks attached to the fuselage. The plans actually leave you hanging after they say "drill #40 the tracks to the fuselage" and never tell you when you should drill up to the final size and put the screws in. I reasoned that it makes sense to do it now, or else the clecoes would prevent the canopy from opening and closing while you're working on it.
Update: It's easier if you leave all but the two end holes at #40, so you can tweak the position of the tracks later on if you have to.
I likewise drilled and countersunk the slide rail for #6 screws and installed it temporarily on the fuselage.
Update: Again, only attach the rail at the forward-most and aft-most ends at this point. Later on, when the canopy is almost finished, you can drill the remaining holes. If you do it this way it will be easier to build a canopy that slides easily.
Behold, the canopy in its closed position:
…and slid to the open position:
I have a little interference between the skin and the rear canopy bow on the right side. I need to tweak the bend there and then I think I'll be done fitting the canopy frame.
