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Common RV-7 Modifications?

SonexGuy

Active Member
Has anyone kept a list of common RV-7 modifications? I'm just starting the tail, but having plans-build a Sonex, I know it's good to find out well ahead of time what changes you might want to make so you can plan around them. I've done some Google searches, but didn't find much.
 
I managed to keep a fairly complete list of mods, deviations from plans, and significant after-market goodies that I did throughout my -7A tip-up build. Hopefully it gives some inspiration or ideas. Happy to answer any questions about any of them in PM, but you can find better info about almost all of them by searching VAF. Note: Mods tend to add time, weight, and risk. Balance the benefit against those.

Disclaimer: Not making recommendations for your particular plane! They're for my plane, which has not been flown yet.

Empennage
Nutplates for additional counterweights in elevator ends
Trim tab riblets
One-piece empennage fairing
Attached bottom rudder fairing with screws

Wings
Welded aileron pushrod ends to W-818 rods
Delrin aileron stops
Flap up and down limit microswitches
Removable flap hinge pin retaining clips
Wingtips attached with hinges
FlyLEDs landing and taxi lights in wing leading edge
FlyLEDs nav, strobe, and tail light kit (installed in wingtip and rudder fairing)

Fuselage
Routed 3/4" conduit under seat and baggage floor
Alternate location for tail light wire passthrough hole in aftmost fuselage bulkhead
Outside Air Temp probe installed in right aftmost tail inspection panel
Inboard seat ribs have portions made removable for control column access
Added stiffeners under armrests
Lighting installed in the baggage area
Button-removable passenger-side control stick
After-market aluminum rudder cable fairings
Plastic tow bar mount installed on baggage bulkhead
Rigid camera mount above baggage area
Interior courtesy lighting installed above baggage area

Panel/Subpanel
Subpanel parts modified to fit deep comm radio
One-piece panel (no vent "ears")
Hinge-removable electronics "tray" added forward of subpanel
Bug screens inside fresh air vents

Canopy
Canopy jettison handle extends only to subpanel and is secured there
Canopy bonded with sikaflex instead of metal fasteners
Ball stud mount for tip-up struts
Plastic canopy guides on roll bar
JD Air tip-up canopy latch
Stronger spring for aft canopy handle
Canopy open indicator microswitches on each side
Adjustable forward canopy stops

Gear
Anti-splat sealed wheel bearing mod (all three wheels)
Aluminum jack points on main gear assemblies

Engine Controls
Repaced BLK THROTTLE 50.5 with custom (53 in.)
Replaced RED VMIXTURE 50.5 with RED VMIXTURE 51.5
Throttle cable to actuator linkage moved outboard for smoother throttle motion

Electrical
Scratch-built wiring harness for all electrics
Forrest of Tabs ground block
Modified starter solenoid wiring to facilitate starter engage discrete indicator
Piper-style ground power socket
After-market (B&C) 40 amp alternator with external voltage regulator

Firewall Forward
All engine compartment fluid hoses firesleeved
Reinforced oil cooler baffle mount with aluminum angle
Oil quick drain valve
Metal bellmouth flanges for baffle mounted magneto cooling ducts
Electrical terminal block mounted to aft baffle for aux temperature sensors

Air Intake
Cylinder 1 and 2 air dams removable
One-piece fiberglass intake snorkel, flange molded to fit cylinder 2 air intake ramp
Modified alternate air door to be close-able from cabin

Cowl
Aluminum oil door with two open buttons
Front cowl aluminum hinge pin covers
Cowl louver slots 1/2" instead of 13/16"

Brake System
Parking brake valve installed on cabin side of firewall
Microswitch to indicate parking brake engagement
Alternate brake line routing through firewall
Reinforced mount for brake fluid reservoir
Check valve on top of brake fluid reservoir
Stainless steel braided brake fluid hoses in cabin and on gear legs
Single "long bolt" for brake pedal pivot
Brake pedal return springs

Fuel System
Delrin spacers between fuel tank ribs and capacitive aluminum plate senders
Dual flop tubes for fuel pickup
Added flop tube anti-hangup brackets
Aluminum fairings for fuel vents
Aluminum fairings for fuel drain valves
Alternate fuel vent line routing inside the fuselage
Fuel flow transducer mounted on top of engine next to divider
Aftermarket fuel tank selector

Pitotstatic System
After-market static ports
After-market pitot tube mount
Metal bracket for securing pitot and aoa tubes running behind aileron bellcrank

Safety Systems
Insulated firewall with fiberfrax and 0.005" titanium foil over top
Crotch strap brackets 1/4" apart, requiring spacer washers
Fire extinguisher mounted between pilot and passenger seats
 
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Ryan, nice list! Looks like we have a lot of mods in common, wish you had built yours right before mine!
 
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List

Yea. That's almost the same as mine. I forgot how many there were!
A few of my mods
-Barringer brakes, wheels, tires
-Removable floors
-Flyboys internal rudder stop
-Flyboys Fuel Vents and Drain covers
-Plenum
-Top Cowl inlets cut and bonded to the bottom cowl
-Aircraft Flight Systems Aircraft Control Module
-Sika canopy and windshield with one piece fiberglass skirt and trim
-Supertracks
-Skybolts. No hinges
-Hinge mounted wing tips
-Wingtip stiffeners
-Firewall mounted RV-10 oil cooler
-P-mags
-TS Flightlines oil, fuel & MP lines
-Upgraded Heat Muff
 
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Thanks for a great starting list!

I scratch-built a Sonex, and made plenty of mods, so I know you have to pick and choose what's right for you, and avoid added weight and time. I am planning to do the slide-back canopy with the rail extensions.

Knowing what might want to be screws rather than rivets helps. There were several of those on the Sonex, too.
 
Some things are personal "improvements" some a highly functional changes that make life better. You can decide from lists above and a few that come to mind here. I made many. About half were required after something went poorly. Many things I did are now part of the kit!!

On my third annual inspection I added spacers to secure the crotch trap verticals together. Otherwise when the floor was reinstalled it always moved and made it a challenge to install the forward screws. This IMO is not a mod but improvement necessary for time saving and sanity.

I left the blue film on the elevator (save the rivet strips) and fully balanced each side that way, then used a nut-late mounted inside-aft to rebalance after the blue film removal. I did some calls that paint was about the same area weight as the blue film. YMMV

Plan all the avionics locations then redesign the canopy release (tipper) for either remote operation or secure it. Either way, a mod will be needed specific to your installation.

If a -7, be sure to remove enough of the lower rudder fairing so it can be removed. It took more than I thought. Also, install the tapered pin for the tail spring when it is on the bench, it is a PITA later.

New style static ports.

Just think ahead about living with the plane and it will guide your way.

Happy Building!
 
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CG mods

If you are building a -7 with anything other than a heavy constant speed prop you need to consider the CG implications as the CG can be quite aft with a lightweight prop/engine combination limiting your baggage carrying capacity (weight not volume). A Catto prop for example only weighs about 14lbs versus the 42+lbs of a Hartzell CS which then requires the addition of a heavy crush plate, landoll ring etc.

You can get a mount that moves the motor forward a couple of inches which helps. Other areas to consider are the 149NL or B &C starters which are about 1 Lb heavier than the skytech CS lightweight starter.
Just something to consider.

Other useful mods as mentioned are supertracks or slider/tip up mods for access to the baggage compartment, upgraded tail wheel yoke and eyelets for the chains, forward deck access panel kit, hinged front battery case (or similar mod).

If you are planning a 3 blade prop and plan to have the snout, make it removable as getting the lower cowl off is a PIA.

Egress handle on the roll cage to make it easier to get out and the RV-14 seat mod if you are taller than about 6ft, also move the rudder pedals as far forward as you can.

If you plan to fly long legs don't put in a lower center console as it restrics your ability to move your legs around for comfort.

Do insulate the firewall as the passenger side gets hot from the heater valve even when closed.

There are tons more, many of which are personal preferences, even though my -7 has been flying for 14 years I have constantly added mods or clever ideas that I have seen on other RV's.
Figs
 
Disclaimer: I'm still building

Tuckey tanks
Electric aileron trim tab
Piper blade pitot
Removable baggage floor (nutplates)
Fwd access panels
DanH style firewall insulation
Jack points at the gear
380 tires
SDS EFI
Superior cold air sump
Supertracks
Cooling/defog fans on the glareshield
 
Most of mine are somewhere in the lists already provided, so I'll just add

Screwless spinner
DJM Throttle quadrant instead of Cessna-style push-pull knobs
Andair fuel pump allowed me to cut the height down on the cover, and I mounted the fire extinguisher there with a really nice racing-style quick-release mount
That one allowed me have Classic Aero make a nice cover for the flap bracket mount, to match the interior
Local auto upholstery shop fabbed up similar covers for the portion of the canopy where the rivets are visible on the interior, with material from Classic Aero to match interior
Removed canopy release handle (radio stack interfered, and we tried all sorts of unsatisfactory solutions, eventually decided screw it); and instead of bolts through the hinges, I used quick-release pip pins with an L-shaped handle. The canopy hasn't been off since it was painted 9 years ago :), anyway.
Wemac vents
Anodized rudder pedals, machined ball mounts for tip-up struts, canopy latch, canopy exterior lift point
Upper tip-up canopy lock cover to hide the mechanism
LED strip under the panel cover portion of the canopy (dimmable)
Rudder cable clevis fairings
Hi-loks fasteners instead of screws for canopy to canopy rails (and Sikaflex all around)
See-through brake reservoir (forgot who made this, dunno if they're still around)
Split all 3 nylon blocks for the brake mounts...a real time- and frustration-saver :)
Cockpit footwell lighting installed up under the dash
Aveo position/navigation lights all around - zero radio noise from RFI! Also, ALL electrical grounds go back to the FOT, none use airframe grounding, so that may have helped there, too
AVEO Rockrack switches, but I don't think they make them anymore :(
Oil cooler shutter
Oil cooler shutter, Alternate air and Cabin heat locking push-pulls from McFarlane with laser-etched labelling (and color-coded blue, red and black, resp.)
Engraved fuel caps (no stick-on labels on the wings...in fact, *everything* on the plane is self-labelled...there are no labels on the panel itself...every button, knob, etc., has the function labelled on the item itself)
Main, Essential and Hot busses with ATO fuses behind the passenger side of the panel; no resettable-in-flight fuses or CBs (BUT...I did full FTAs and fault trees on the electrical system to ensure that no safety of flight conditions could be created by this design)
Keyswitch interlock for mags and starter (LOTS of debates about this on this forum...have fun!)
Hex rods for flap actuation rods to replace the standard cylindrical tubes (torque tube-to-flap rods)


That's all I can think of (that hasn't been mentioned elsewhere). Lots of fit and finish work, like epoxy w/ microballoons to fill and blend things like empennage tips, etc. (Tons of work on those, btw, but they look *great*). PM if you want details on any of them.
 
First time builder

Some advice about mods I wish I would have gotten .

If you are a first time builder DO NOT MODIFY ANYTHING ! STICK TO THE PLANS FOR YOUR FIRST BUILD …

One exception would be if you have other builders support that have done mods themselves that will be helping you every step of the way

It’s easy to fall down the rabbit hole of modifications
 
Some advice about mods I wish I would have gotten .

If you are a first time builder DO NOT MODIFY ANYTHING ! STICK TO THE PLANS FOR YOUR FIRST BUILD …

One exception would be if you have other builders support that have done mods themselves that will be helping you every step of the way

It’s easy to fall down the rabbit hole of modifications

I'd have to disagree with that. I scratch built a Sonex (in 5 yrs, 3 months) that I have been flying for 9 years, and have plenty of modifications that have made the aircraft better suit me, made it more maintainable, and gave me tons of satisfaction.

https://www.youtube.com/watch?v=Lbgek8-X14o

All things in moderation, of course. You can certainly go down a rabbit hole if you let yourself, but modifications are what "experimental" is all about. Each year I take dozens and dozens of photos of other aircraft to get ideas for things I'd like to do, and to see how to best execute them.

For instance, for the RV-7 with a slideback canopy, the Super Tracks modification is going to make the baggage area actually accessible. My wife looked at one with and one without, and she wondered why anyone would build it without the extension that the Super Tracks allows.

To each their own...
 
True

for the RV-7 with a slideback canopy, the Super Tracks modification is going to make the baggage area actually accessible. My wife looked at one with and one without, and she wondered why anyone would build it without the extension that the Super Tracks allows.

The Supertracks mod was a HUGE improvement to my -9A slider. Second only to the autopilot in terms of upgrades I’ve made (and unlike the autopilot, I haven’t had to replace any Supertracks components twice :D). Definitely easier to do BEFORE the airplane is completed.
 
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