RV-7/7a Plan Gottcha's

[wirejock]

Originally Posted by idubrov

Got it.

But I see another "gotcha" here: the firewall doubler from OP-32 reuses two of the holes on the firewall. Since it goes to the front of the firewall, the firewall (ideally) should not be dimpled in these two holes (and stiffener behind the firewall should not be counter-sinked). Right?

Sounds right. I do remember making a a larger doubler to allow the contactor to sit even to each other. Can't remember why. It made sense at the time. Found a photo.

[PilotjohnS]

Originally Posted by wirejock

U-00713C, DWG-C1, Nose Wheel Fairing Bracket
They are loose if you follow Vans plans. The vibration couldn't be a good thing. Here's the fix.
The nose pant brackets are fixed.
If you haven't bored the forward holes to Vans dimension, just carefully bore them so the flat washer is a tight fit then add a stainless washer outside so the lock washer and hex bolt hold everything tight.
If you did bore the holes...
Buy washers. Two grade 8-5/16" washers and two 3/8" stainless washers. The grade 8 were ground down to fit tight in the forward holes then bored to 3/8 ID. That helped a lot. The stainless were placed over the holes and under the lock washers so the bolts would lock it down. Now the brackets are solid.
Attachment 27890

Larry, thanks for this. I am doing this now. What I plan to do is just drill the front hole for the bolt, like you suggest. So to pull the wheel pant, I will remove the allen bolt on each side. In addition, those allen bolts are 3/4” long and stick thru the fork towards the sidewall of the tire. I was going to add washers so the bolt is even inside. This will also give me about 1/2” for the tow bar to have a good perch. Here is a picture of what I was thinking. I will probably make a bushing to replace those washers and make the outside dia same as the allen. bolt head. Any comments?

Thanks

[wirejock]

Originally Posted by PilotjohnS

Larry, thanks for this. I am doing this now. What I plan to do is just drill the front hole for the bolt, like you suggest. So to pull the wheel pant, I will remove the allen bolt on each side. In addition, those allen bolts are 3/4” long and stick thru the fork towards the sidewall of the tire. I was going to add washers so the bolt is even inside. This will also give me about 1/2” for the tow bar to have a good perch. Here is a picture of what I was thinking. I will probably make a bushing to replace those washers and make the outside dia same as the allen. bolt head. Any comments?

Thanks

Exactly what I did. I replaced the two brackets and did as you mentioned. Brackets are tight. Nose pant it tight.
Edit...
I read the plans wrong. The 11/16" hole is drilled in the pant for the tow bar. Duh! The bracket is bolted with the socket head screws. Watch the excess screw protruding in toward the tire. I added a washer or two to move the bolts outboard a little.

[idubrov]

Another gotcha: https://vansairforce.net/community/s...d.php?t=209714

Sadly, I did not see that post and got myself into the same pickle (and I did my best to mark the hole before the drilling so it did not move):



I am still able to force the bushing in (after trimming it a bit), but its wire capacity will be reduced a bit.

Good thing is that these bulkheads allow few more places where holes can be drilled, so I'll see if I need to add more.

Also, the plans say to drill two 5/8" holes in the middle, but I already had 3/4" holes in that location (now I only need some SB750-10 bushings...).

[idubrov]

Called support -- they said relieving F-704C/D is okay. Will be watching for the wing spar web in the future.

[wirejock]

This one is more of an embarrassment than a Gotcha, but i is a heads up for others.
Baffle Tension Rods
Vans says grab the .120 Stainless Hinge Pins provided in the baffle kit. Cut to length per plan and thread the ends 6-32. Easy right? Not for me. Go ahead. Start laughing.
Cut. No problem. Of course, I'm kinda OCD, so both exactly the same length and ends are perfectly square.
Clamp in the vise with some sacrificial aluminum to protect the rod.
Start threading. I place the die on the rod and it slips right through. Wait a minute. What's going on? Take it to the bench. Measure with a caliper. Yep. Right size. Check the die. Yep. Right die. Poke the die with the rod. Correct. Oh Bother. It went through one of the waste holes. Feel so stupid.
Back to the vise. Carefully start threading. Die won't cut. An hour of leaning my 200lbs on the die handle while turning yielded a scratch. Dang this stuff is hard. Idea!
Grind a tiny taper on the end.
Back to the vise. Yea! Cutting like a Gin Su knife. Hour later all threads cut on ends of two rods. Time to install.
Rod won't fit. Doh! I never drilled the holes for #6 (#29). Oh Bother. Three holes were not too bad with a 90 attachment but the fourth was like digging a tunnel with a dull spoon. Finally found a #30 screw bit the right length and got it drilled. Inboard tension rods installed. Four hours.
Moral...
Drill those tension rod holes when you prep the baffles.
Grind a tiny taper on the end of the tension rod so the die will bite.
Ok, I can hear everyone laughing. Get back to Building!

[idubrov]

So I thought I was smart to do the crotch straps early in the build. After all, you can attach with them with solid rivets, and be proud of it!

What I did not realize fully is how much things move once you start assembling everything together. I did make an effort to stabilize everything (I think, I clecoed the floors).

Look at this. The holes are not even close!




I can move them a bit fore to aft, but I cannot move them left to right. I have no idea how did I manage to drill them so badly (I checked my logs and it seems I drilled the holes with the bottom skin and both removable floors installed. I did not, however, cleco the "permanent" floors).

If I were to do it again, I wouldn't drill the top four holes until I had the entire center piece assembled so it is as rigid as it can get. It seems like it shouldn't be an issue to rivet nutplates with crotch straps installed. There is enough space to fit the squeezer, I think.

[fabio]

Originally Posted by Iluke

Here are some pictures of my homemade throttle bracket. Like other's the Vans supplied bracket positioned the cable too low. I made this out of 4130 sheet. It positions the cable higher, closer to the sump. As an added benefit, it gave the cable a slightly better angle relative to the linkage.
Haven't flown yet, but I have run the engine on the ground and no problems so far.

Mine is a factory Lycoming IO-360-M1B bought through Vans.
Attachment 12865

Attachment 12866

Attachment 12867

which is the vans p/n of the exhust cable protection?

[wirejock]

Things I wished I had done earlier...

-ADAHRS shelf. Huge pain to install. It would have been so much easier at canoe stage.
-Pathways. Snap bushings around the panel and sub panel. Also a pain. Put them in before the top skin. Mine are 1" and they are really getting tight. One each side as well as one through each sub panel rib to cross over.
-Antenna doublers and holes. Pain. Figure out where and install at canoe stage.
-Wire. Any wire you can. Make a plan and snake as much as possible.
Tip...
Make a journal or generate some seriously detailed schematics. Wire guage, colors, connectors, etc from end to end. A detailed list really helps place orders for wire and really helps when it's time to actually pull wires. I have a spiral where I kept notes detailing each device, wire guage, colors, everything. It really came in handy pulling all that wire. It saved me from pulling out manuals and schematics and digging to figure out wire dimensions.
My schematics show the details, but it's so much easier in a journal.
Another Tip
Buy one of these
Nice pad folds into various sizes. The slick surface is easy to slide.

[Draker]

Originally Posted by wirejock

Make a journal or generate some seriously detailed schematics. Wire guage, colors, connectors, etc from end to end. A detailed list really helps place orders for wire and really helps when it's time to actually pull wires. I have a spiral where I kept notes detailing each device, wire guage, colors, everything. It really came in handy pulling all that wire. It saved me from pulling out manuals and schematics and digging to figure out wire dimensions.
My schematics show the details, but it's so much easier in a journal.

Yes, you can't beat having a complete schematic on hand before you start running wires.

Since my build log/journal is a spreadsheet, I made a tab just for circuits. For each circuit in the harness, I noted down: Circuit name, Wire Gauge, Type (power, signal, light, audio, etc.), From / To, and a list of bulkheads each circuit needs to pass through in what order. And then checked each one of only after the entire circuit was installed connector to connector.

From that, you can answer questions like "how much 22 gauge wire will I need?" and "are there too many wires going through bulkhead X?" and "what size connector will I need to handle all the wires going to the wings?"

If you're doing a full-on Dynon or Garmin EFIS airplane with lots of electronic goodies, you'll have upwards of 400 circuits to run! Gotta keep em organized.