What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV-7/7a Plan Gottcha's

Doubler

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.
20210204_163009.jpg
 
Thanks Larry

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.
View 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
 

Attachments

  • D5456860-09B7-41E9-954C-FCB142979DB8.jpg
    D5456860-09B7-41E9-954C-FCB142979DB8.jpg
    434.6 KB · Views: 146
Last edited:
Nose pant brackets

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.
 
Last edited:
F-704 electrical wire bushing holes

Another gotcha: https://vansairforce.net/community/showthread.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):

IMG_6641.jpeg

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

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!
 
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!

IMG_6811.jpeg


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.
 
Last edited:
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.
View attachment 12865

View attachment 12866

View attachment 12867
which is the vans p/n of the exhust cable protection?
 
Finishing Tasks

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.
 
Last edited:
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.
 
ExpressSCH

I used ExpressSCH to draw up schematics of all the circuits and pin-outs. The software is free and easy to work with.
 
F-695 gussets are, as per tradition in that area, a minefield of edge distances. Which is amusing given how trivial the part is.

Couple of things to keep in mind:

1. There are 14 holes on the long side, not 10 (10 rivets attach to the engine mount, then 4 more attach to the longerons).
2. The aftmost of these 14 rivets gets a very short edge distance if you lay everything out as per plans. The plans do say "TYP." for the dimensions, however, which means you need to adjust them as needed.
3. Watch for the edge distance both on the longeron and the engine mount behind (below) it. On the aft end, I have about 1/2" overlap between the longeron and the engine mount, so a perfectly positioned hole will get about the 0.250" edge distance. Hitting 0.219" (as per MIL-Spec) is realistic, but it's only a 1/32" difference, not much. Although, not unusual in the forward fuselage area.
4. Watch for the location of the fourth from the aft rivet (the first one that only attaches to the longeron). You want this rivet to be away from the engine mount edge so you have some space for the shop head.

So I successfully managed to avoid the minefields #1 to #3, but #4 got me :D Luckily, I only drilled the gusset, not the longeron / engine mount, so I am just going to replace the part.
 
Rod ends

Advise
Working on the control column weldment.
Install the rod end bearings before installing the weldment.
I just spent hours installing the rod end to the pitch control rod. It's in a really difficult place to work. I could have just installed it early on. The rod screws right into it
Another one
The opposite end. The pitch control bellcrank where both rods come together behind the baggage bulkhead.
The bottom bolt goes in from Port to Starboard. No way to install it without removing the bellcrank. Install the bearing before installing the bellcrank.
 
Advise
Working on the control column weldment.
Install the rod end bearings before installing the weldment.
I just spent hours installing the rod end to the pitch control rod. It's in a really difficult place to work. I could have just installed it early on. The rod screws right into it
Another one
The opposite end. The pitch control bellcrank where both rods come together behind the baggage bulkhead.
The bottom bolt goes in from Port to Starboard. No way to install it without removing the bellcrank. Install the bearing before installing the bellcrank.

Do the plans for the RV-7 show an access hole in the rib for this bolt? This hole is shown on the plans for the older -6 and I don't recall having that problem there. It's easy however to fit/remove/re-fit the bell crank.
The tiny washers beside the rod ends on the control column (and aileron bell cranks) are a real hassle.
 

Attachments

  • 16887697108235547961267189465649.jpg
    16887697108235547961267189465649.jpg
    153.2 KB · Views: 44
Last edited:
Advise
Working on the control column weldment.
Install the rod end bearings before installing the weldment.
I just spent hours installing the rod end to the pitch control rod. It's in a really difficult place to work. I could have just installed it early on. The rod screws right into it
Another one
The opposite end. The pitch control bellcrank where both rods come together behind the baggage bulkhead.
The bottom bolt goes in from Port to Starboard. No way to install it without removing the bellcrank. Install the bearing before installing the bellcrank.

:) I know EXACTLY where you are talking about Larry! What a PITA!
 
Access hole

Do the plans for the RV-7 show an access hole in the rib for this bolt? This hole is shown on the plans for the older -6 and I don't recall having that problem there. It's easy however to fit/remove/re-fit the bell crank.
The tiny washers beside the rod ends on the control column (and aileron bell cranks) are a real hassle.

You are absolutely correct. Thanks for the heads up. I couldn't see that hole from where I was laying down. Good thing I didn't take it apart. Dodged one there. Thank you.
 
Access hole

Well, there is an access hole. It does allow the bolt to be inserted and a socket used. However, it's still an avoidable royal pain in the tuckuss. See my tip in the Tips section. Just install that bearing before installing the bellcrank. Save yourself a full cuss jar. Unless, of course, you enjoy installing bearings upside down in a tail cone. :D
 
Tightening spring on elastomer nose gear mount

If you are building a -7A with the new style "elastomer" nose gear mount, pay close attention to the instructions on DWG 46A for the MS21045-6 nut that compresses the cap and spring:

WITH NOSE WHEEL INSTALLED (SEE DWG C1) AND OFF THE GROUND, TIGHTEN UNTIL SPRING-00003 IS FULLY COMPRESSED AND NO GAP EXISTS BETWEEN ELASTOMER PAD AND ELASTOMER, SEE NOTE 4.

NOTE 4 also explains how to re-adjust as the elastomer pads slowly wear down.

If you miss these notes, your nose gear will hang down in flight and have a lot of free play during landing. Incorrect!
 
If this hasn’t been addressed yet….


When you install your rudder pedal weldements and are drilling into the longeron for the for and aft positions, try to place the bolts in between the skin/longeron rivets. Otherwise when you go to install the nuts you won’t be able to fit them because the shop head will be in the way.
 
Dimple NOT countersink the forward face of the L/R Elevator spar E-702 for the 706/5 attachment. 702 is too thin to countersink and you'll end up with a hole larger than spec. THANKS VANS!!!! FIX YOUR **** INSTRUCTIONS!

FWIW, I asked them about this particular area. I suggested using NAS1097 instead, since they have a smaller head. I did not want to dimple as I wanted parts to sit completely flat (since there is this whole horn that mounts over them). I know some builders dimpled, though, and it worked fine.

The answer was to follow the plans, so I did countersink for AN426AD3, but I did it without a cage, manually, carefully controlling the depth. The E-702 is 0.032" and the "full" countersink depth for AN426AD3 is about that exact depth. So you do get a knife edge.

Either way, I don't think it matters much as this steel horn over these two parts won't let anything to move anyway.
 
Last edited:
FWIW, I asked them about this particular area. I suggested using NAS1097 instead, since they have a smaller head. I did not want to dimple as I wanted parts to sit completely flat (since there is this whole horn that mounts over them). I know some builders dimpled, though, and it worked fine.

The answer was to follow the plans, so I did countersink for AN426AD3, but I did it without a cage, manually, carefully controlling the depth. The E-702 is 0.032" and the "full" countersink depth for AN426AD3 is about that exact depth. So you do get a knife edge.

Either way, I don't think it matters much as this steel horn over these two parts won't let anything to move anyway.

You MUST take the cage off in order to fit against the fillets.

If you do the trig, the depth of the countersink works out to 0.037" deep which is greater than the E702 thickness of 0.032". That means the hole is enlarged (not just knife-edged) and it's beyond the mil-spec.
 
You MUST take the cage off in order to fit against the fillets.

Right. I have a small adapter that I can either chuck in a drill or spin between fingers to create a countersink.

If you do the trig, the depth of the countersink works out to 0.037" deep which is greater than the E702 thickness of 0.032". That means the hole is enlarged (not just knife-edged) and it's beyond the mil-spec.

I used numbers (well, the head diameter primarily, but it matches the one I measure with the calipers) from https://www.univair.com/hardware/ri...-rivets/an426ad3-3-100-deg-countersunk-rivet/

The formula is tan(50 degree) = (B - C) / 2h, where h is the depth. h = (B - C) / 2 / tan(50), which is (11/64 - 3/32) / 2 / tan(50 degree) ~= 0.033. Which is a tad thicker than 0.032" material, but just one thou. And you can leave rivet sticking just a bit, per spec, if you really want to (but in this specific location, given the steel bracket on top of it, it probably shouldn't stick too much).

Which is consistent with Section 5, also:

For AD3 rivets, a total material thickness between .016 [.4 mm] and .032 [.8 mm]
must be dimpled. Material thickness between .032 [.8 mm] and .040 [1.0 mm],
should be dimpled, but a countersink may be used if necessary.

Either way, what I am saying is that I don't see much reason to stress over these specific holes. I don't like the way it is specified in the manual, but I assume that changing anything in the manual is a bigger risk for Vans than leaving as is. What they specify probably works.

Just a heads up, they will ask you to countersink E-606P as well, which is also a 0.032" spar.
 
Last edited:
Not really a gotcha, more like something that made me chuckle.

I was trying to verify the 0 degree incidence angle on the horizontal stabilizer, and just couldn't get the fore and the aft tooling holes to align (which is what instructions tells you to check).

Then I looked at the other side, and realized that the aft tooling hole was indeed not centered on the rib.

1-tool-holes.jpg

I know, it is kind of obvious if you look at the lightening holes, but I had some sort of a tunnel vision seeing only the tooling holes :rolleyes:

The fore hole seems to be centered, though.

I wonder, if it was a downstream effect of SB 14-01-31 integrated into the plans when they replaced HS-405 ribs (or whatever was there before in RV-7 plans) with the HS-00005 ribs?
 
Tooling holes

Not really a gotcha, more like something that made me chuckle.

I was trying to verify the 0 degree incidence angle on the horizontal stabilizer, and just couldn't get the fore and the aft tooling holes to align (which is what instructions tells you to check).

Then I looked at the other side, and realized that the aft tooling hole was indeed not centered on the rib.

View attachment 47079

I know, it is kind of obvious if you look at the lightening holes, but I had some sort of a tunnel vision seeing only the tooling holes :rolleyes:

The fore hole seems to be centered, though.

I wonder, if it was a downstream effect of SB 14-01-31 integrated into the plans when they replaced HS-405 ribs (or whatever was there before in RV-7 plans) with the HS-00005 ribs?

Yep. I measued all day on that one. Finally realized the holes were not matching the manual. Legacy manual instructions I guess. In the end, I trusted the actual measurements and ignored the holes.
 
Not a "gotcha" but file this one under "things I'd do differently if I built another one":

When installing the VA-168 sensor manifold (for oil, manifold and fuel pressure sensors), the plans have you put AN365 nuts on the cabin side of the firewall. To ease maintenance, I feel like it would be better if these were nutplates. Or really anything on the cabin side that holds a bolt from the engine side. Ask my lower and upper back why.
 

Attachments

  • VA-168.png
    VA-168.png
    273.8 KB · Views: 22
Last edited:
Not a "gotcha" but file this one under "things I'd do differently if I built another one":

When installing the VA-168 sensor manifold (for oil, manifold and fuel pressure sensors), the plans have you put AN365 nuts on the cabin side of the firewall. To ease maintenance, I feel like it would be better if these were nutplates. Or really anything on the cabin side that holds a bolt from the engine side. Ask my lower and upper back why.

Ryan,
Great idea but you would have to move it off that rib.

Boomer
 
Manifold

Not a "gotcha" but file this one under "things I'd do differently if I built another one":

When installing the VA-168 sensor manifold (for oil, manifold and fuel pressure sensors), the plans have you put AN365 nuts on the cabin side of the firewall. To ease maintenance, I feel like it would be better if these were nutplates. Or really anything on the cabin side that holds a bolt from the engine side. Ask my lower and upper back why.

Totally. I wish I had.
I did cut one port off. Only two are used. I also added a shim to allow the sensors to be installed sideways without touching the firewall.
 
Back
Top