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What would I do differently on my RV-4

S

svanarts

Well Known Member
I'm planning on building an RV-7 so I asked the 7 guys what they would do differently. I built an RV-4 so someone asked me to post here what I would do differently if I were to build my RV-4 again so here it is:

  • Install RV-6 fuel tanks rather than the stock RV-4 tanks. That's an extra hour of fuel. Would come in handy out here in the west. It's not a bolt on replacement, you'd have to order the RV-6 fuel tank parts and then cut your wing to suit. You'd probably only need the 6 tank skin and a couple of extra nose ribs.
  • Completely finish and paint the plane before flying. Get the fiberglass all done and paint everything as you go along if possible. At the very least get all the fiberglass done and primed before you fly. It's been two years and I'm still trying to finish my plane. :)
  • Manual flaps from the start. I ripped my electric flaps out after the motor started smoking.
  • Doug Bell tailwheel. Van's stock tailwheel will catch on almost anything. The Bell tailwheel is a nice piece of work.
  • Rear seat footwells a la RV-8. The pax feet can get awful sore without these.
  • Electric elevator trim. That manual trim cable is heavy and bulky. I'm retrofiting an elect trim system now.
  • 180 motor and CS prop. Go this route and you will have NO CG problems.
  • Dynon FlightDEK 180 or ACS3500. Minimal steam gauges.

Some things I did do and would do again:

  • Minimal instrumentation. Basic flight instruments and a Rocky Mountain MicroMonitor. Saved weight.
  • No fancy upholstry. Just cushions, no fabric on the sides. Saved weight.
  • Combo strobe/Nav lights with rear pos lite on the wing tips. Keeps more weight out of the tail.
  • Single point ground.
  • MicroAir radio and transponder that fit the 2.5 in instrument hole. Great little radio.

My RV-4 came in under 800 lbs and flies great. Leave as much weight on the ground as you can.
 
RV-4 Mod

I agree, if you don't have it it can't break. My -4 has 180 with wood prop, and I have no CG prblems. I'd question the benefit of a CS prop. Too heavy and cuts in to payload too much, plus a fwd CG. Mine weighs 960lbs with oil @17%MAC. - is that a typo '800lbs empty' for you? If so, how? and congratulations! I have no lights or gyros, steam gauges, radio and transponder. Electric trim and manual flaps, no upholstery. Rear seat controls but no foot wells. Again, well done with weight, what are your tricks?

VH-PIO 250hrs
 
160 hp engine with a catto prop, very light instruments, and if I didn't need it I left it off. Simple light upholstry. No paint either. :)
 
Scott - thanks very much for posting your thoughts. (It was me that asked.) Its a great help to thoise of us still building. I'm very much on the same wavelength as you with a couple of minor differences.

Did you really mean 800 lbs?

Cheers.
 
No way Scotts (or any) RV4 came in under 800 lbs.
Sorry
Tom
RV3, 0320, catto prop, day vfr, not a lot of paint,
787 lbs empty.
 
Down here in the South Texas I wish I had a tinted canopy - AND an autopilot.

My O-320 150 hp w/a 3 bladed Catto prop is great - very smooth too. It won't set any "time to climb" records but the 175 mph cruise on 7 gal/hour is fine.

Bob Richie
 
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since i bought my rv4 last summer i have
1 strenghtend firewall for main landing gear
2 changed from plastic brake line to aluminum [from firewall to caliper with aluminum]
3 replaced all cowl piano hinges [best quality piano hinge its not a waste if you have to change them every 350 hrs]
4 just overhauled the tailwheel [fiberglass etc]
5 i also turned my bolts for my rudder with nut on the inside[nut on outside seemed to rub on firewall in 2nd position]
6 and oh ya that dipstick ive glued that for the second time this time itll hold
 
avengingangel said:
since i bought my rv4 last summer i have
1 strenghtend firewall for main landing gear

4 just overhauled the tailwheel [fiberglass etc]
Click to expand...

Could you elaborate on these? How do you strengthen the main gear and what do you mean by fiberglass?
 
Steve Sampson said:
Scott - thanks very much for posting your thoughts. (It was me that asked.) Its a great help to thoise of us still building. I'm very much on the same wavelength as you with a couple of minor differences.

Did you really mean 800 lbs?

Cheers.
Click to expand...

:eek: No! I really meant 900 lbs! It weighed in at 876.

Viva le differance! That's why you should build your airplane. No one will make it suit you better than you! Enjoy the build process. I like it so much I'm starting again.

Tin Man said:
No way Scotts (or any) RV4 came in under 800 lbs.
Sorry
Click to expand...

It was a typo Tom. Or is that still too light? :)
 
Last edited:
Scott
I just read my post and it sounds a little harsh No way I ment to sound that way, I apoligze. The real wieght sounds pretty lite, you have done a good job in keeping wieght to a minimum.
Happy flying
Tom
 
No need to apologize Tom, I was just ribbing you a little. :p

I do need to reweigh the plane since I've added some things. I expect that it will come in over 900lbs once everthing is there and painted.
 
different?

My target weight is 1,000#'s; 900 is my dream weight and I did everything similar. Minimal steam, no upholstry just cushions and an IO-320. I like the bit about single-point ground. I wired mine more like a glass ship, all grounds run back to the single-point AN-3 ground bolt in the stick & right-side floor compartments. I hope I dont have to track down any humming in my headset.

On the paint... I'm glad you mensioned that. My plan was to prime all the glass bits for UV protection now, then near the end of Phase 1 I'd scratch & fill the remainder before delivery to the paint shop to shoot the primer and color. My paint shop is 50 miles away (outside the test range).

-Bruce
 
Lightweights...

When I started the bandit back in 89', a guy recommended I stay stock, simple and light which then meant 0-320 and a wood prop and not much else. After 10 years and 1400 hours not much has changed my original thoughts. Now I have a pumped up 0-320 and MT composite FP prop and it weighs 954 lbs paint and all. I disagree on the 180 C/S, I have flown several and mine just flies better and has a lighter nose for acro and is smoother. I think a pumped up 0-320(or IO-340) and MT 3 bladeC/S would be a better call and lighter. If you use an Odessey battery and mount it on the firewall you don't have CG problems and save 12lbs rather than add 100 (180/Hartzell)!The original unpainted bandit on the test flight weighed 918 lbs which I thought was a victory, <900? You da man Scott...
My list of changes I made over the years almost matches everyone else, Jeff Rose Electroair Electronic Ignition, passenger footwells, good ventilation (Larry Vetterman vents), light weight(no interior, just primer) long gear(mine's an old kit)braided ss lines everywhere especially the brakes, Aviation products Inc. Tailwheel (the best I have seen), Odessey battery on the firewall, extended rear and front baggage area (old batt box, shelf aft of rear inspection door) RV-6 fuel tanks or a set of "Cheese" Wilson's Safe Air one tanks, KLX-135A can't be beat for the money, Trutrak pictorial T&B (lighter than an altimeter!) aluminum plenum chamber, beef-up plates inside the corners of the fwd fuselage, fireproof stockcar firewall insulation everywhere including under the forward floors. Electric rudder trim tab (My Harmon Rocket has one, very nice) Engine monitor rather than 4 EI gauges (cheaper) although the EI gauges are bulletproof!
All in all, the RV4 and it's souped up cousin the HR2 both Rock, all the other RV's just aren't as fun. I like the Rocket for takeoff, climb, cross country speed and alot more room and brute power. The HR2 also has RV fuel burn rates at comparable speeds, but it's hard to fly it that slow :)

The RV4 still flies the best of all...

Rob Ray
 
What would I do Differently on my RV-4

smokyray said:
<beef-up plates inside the corners of the fwd fuselage,
Click to expand...

Rob,

Can you expand on this? Please explain precisely where and why. And thanks for all the great info.

Dan B.
N671DJ
500 HRs
 
just a quick question on your beefed up forward fuselage corners. was that for the main landing gear as i beefed up that area aswell.
 
dbf4n said:
Rob,

Can you expand on this? Please explain precisely where and why. And thanks for all the great info.

Dan B.
N671DJ
500 HRs
Click to expand...
Hi Dan,

Here a couple of pictures of how I beefed up the forward fuselage corners in my rv-4. The pieces are from the RV-6 kit and worked with just minor adjustments just as it shows for the RV-6. I also replaced the small shim that goes between the lower weldment and the firewall with a much larger triangular shim that can just be seen in the 2nd picture.

Bottom Reinforcements

Top Reinforcements

Regards,
Tom Velvick
N53KT rv-4
rv-6a finishing
 
Last edited:
smokyray said:
Electric rudder trim tab (My Harmon Rocket has one, very nice)
Click to expand...

Do you have any good pictures of the rudder trim tab. I've been told by another HRII pilot that he wished he had an eletric rudder trim tab.
 
RV-4 range

Hey.

Does anyone know about tip tanks for my RV-4. I just did a trip from Napa CA to Walla Walla WA and with a quartering 7 knot head wind on the return I was short about 20 min. of fuel. It looks like it is a 3 hour machine. I burned 8.8 gph @ 2600 with a 160 hp 0-320 and a Great American 68/66 prop.

i bought this out of San Diego in May. it has been hanging in the Aerospace
museum there for 15 years. 400 hrs. TT. I love it but want more range.
 
The pieces are from the RV-6 kit and worked with just minor adjustments just as it sh

rvator51 said:
< beefed up the forward fuselage corners in my rv-4.
Regards,
Tom Velvick
N53KT rv-4
rv-6a finishing
Click to expand...

Thanks Tom,

Was there any specific reason to beef up the corners? i.e. known issues, stressed airframe, etc.?

I bought my 200 hour RV-4, have put 300 hours on it in 2 years and it is near perfect in all ways. I am doing the maintenance on it, watching for any trends and looking to other 4 owners and on forums like this for issues that others have. And, of course, I take special note of airframe structual concerns.

Thanks again.

Dan B.
RV-4, 500 HRs
N671DJ
 
dbf4n said:
Thanks Tom,

Was there any specific reason to beef up the corners? i.e. known issues, stressed airframe, etc.?


Dan B.
RV-4, 500 HRs
N671DJ
Click to expand...
Hi Dan,
My wifes rv-4 and the original rv-4 I bought were both built in the 80s and both had slightly buckled/cracked firewalls at the bottom brackets. This happened to a lot of the older rv-4s. Vans came out with heavier duty weldments to address the issue on newer rv-4s and we replaced our original firewall weldments with the newer ones. The additional aluminum angles were placed on the corners for additional strength in that area. I was told that the Harmon rocket crowd does the same thing to their firewalls. I first got the idea from the Bakersfield bunch who had installed them on a rv-4 that they built with a 200 hp engine. Since I was thinking of an O-360/CS combo on the new rv-4 which is a lot heavier than my O-320/wood prop combo, I wanted to make sure that the frame was as sturdy as I could make it to handle the increased weight.
This was an easy mod to do during construction and since the other RVs (rv-6, 7, 8) use these brackets and other builders have recommended them, it seemed like it wouldn't hurt to add them to the new rv-4.
Since Vans doesn't have them on their plans (at least as of the date of my plans), they must feel that they really aren't necessary though.

If you already have the newer style beefier weldments, you shouldn't be concerned.

Regards,
Tom Velvick
N53KT RV-4
N7053L RV-4
rv-6a finishing
 
when i purchased my 4 the lower outside corners where rinkled so i had to strengthen as best i could seeing it was already built.
 
Wheres the Beef-up..or it's a gas, gas gas...

OK, to answer both questions. First, why the firewall beef-up plates? When I built the bandit I had the luxury of having a helper who built six (by 1992) RV4's! He had seen the weakness in the forward firewall area in early RV4 kits and made corner gussets for the lower firewall corners. He sent his idea to Van and they are now incorporated ( I think) in the new RV4 kits post 1995. I'l, snap some photos and upload them tomorrow.
As far as tip tanks go, my HR2 has 5.2 gallon tip tanks hidden under the wingtips fabricated by the builder. They gravity feed and drain dry into the mains beautifully. They are almost identical to my friend "Cheese" Wilson's Safe Air One tanks he builds in Texas. His tanks are the best I have seen and are on the CG, no G restrictions and tested thoroghly over 500 hours and on over 100 RV's now. Check out their site:

See ya!

RR

www.safeairone.com
 
rvator51 said:
Here a couple of pictures of how I beefed up the forward fuselage corners in my rv-4. The pieces are from the RV-6 kit and worked with just minor adjustments just as it shows for the RV-6. I also replaced the small shim that goes between the lower weldment and the firewall with a much larger triangular shim that can just be seen in the 2nd picture.

Bottom Reinforcements
Top Reinforcements

Regards,
Tom Velvick
N53KT rv-4
rv-6a finishing
Click to expand...
Tom, I did the same thing on my RV-3 just based on experience from you -4 guys. No RV-3 drivers are having any problem but I figured it would be good insurance anyway.
Bottom: http://www.romeolima.com/RV3works/Airframe/DSC_0373.JPG
On the top I used the RV-8 triangular supports that triangulate the longeron and the hortizontal stringer across the firewall which should provide extra stiffness from engine shake etc. Can't find a pic of that one.
 
The brake line thread in the RV-4 forum just made me think of another thing I'd do differently. I'd go with metal tubing down to my brakes on the external portion of the brake lines. On the inside I'd still be okay with sticking to the nyloseal stuff.
 
There is one thing on my -4 that is really annoying. I have a strobe in the top of the vertical. For the GIB this is really a bad thing at night. The wings totally light up with each flash. It's not bad for the pilot. I would recommend wing mounted strobes for -4's and -8's.
 
Sit down, shut up and hang on!!

Chuck,
The above is printed on a sticker in the back seat of the D model (2 seat F16) I have it im my RV4 too...:) I actually like my strobe in the top of the rudder. The builders manual has it there and it saves money just having one power supply and strobe. If it's mounted far enough back, the rudder angle blocks it's forward view.
The F-16's strobe is mounted on top of the rudder and it has a small tab in front of it just for that reason. It would be easy to make one for your 4. My Rocket has tip strobes hidden inside the tip and are more distracting than my 4's rudder strobe...

I like the "turn it off option" if it's distracting...

my 2 cents..

Rob Ray
 
Tip Tanks

I have a set of the Johanson tip tanks I will be selling soon, they hold 9 gallons each. They look like the standard -4 tips and are set up for nav & strobe combination lights. I'm having a larger set couston built. My pumped up 0-360 C/S can drink when at high power, is there any other way I file 180K @ 8,000' to 10,000 with 50 gallon total it is great X/C. Mine isn't light but feels much lighter flying than all of the -8 & -6's I have flown.

Bullet

bill price said:
Hey.

Does anyone know about tip tanks for my RV-4. I just did a trip from Napa CA to Walla Walla WA and with a quartering 7 knot head wind on the return I was short about 20 min. of fuel. It looks like it is a 3 hour machine. I burned 8.8 gph @ 2600 with a 160 hp 0-320 and a Great American 68/66 prop.

i bought this out of San Diego in May. it has been hanging in the Aerospace
museum there for 15 years. 400 hrs. TT. I love it but want more range.
Click to expand...
 
TX to FL, Non-Stop...

Bullet,

I flew My HR2 from Carthage TX to Lakeland, FL non-stop yesterday. I have 44 gal capacity with 10 gallons of aux fuel in custom tanks similar to the safe-air-one tanks 54 total. Carthage (4F2) sells SS100LL for $3.00 a gallon and I burned a bit over 33 gallons going 215 knots+ for the 715nm trip. TX to FL for a hundred bucks, in a bit over 3.4 hours, that's a 2 day drive! With the Garmin 396 showing the way with tunes, wx and talk radio, it makes airline travel seem stale, especially with my aileron roll every 15 minutes for good measure!
If you have 50 gallons in an RV4 that burns 10 gph or less at 170 knots you should be able to go alot further than I do. I know the argument for small bladders and landing every 2 hours, but for serious travel and having flown a 32 gallon RV4 for 15 years on alot of trips I have to say, more gas is better. You don't have to fill the aux tanks every flight, only when you need them. The safeair one tanks only add 9 lbs to the airframe. The Johansen tanks don't add alot either. If you remove a stock acft battery and put in an odessey battery when you install the tanks, you break even on weight!
I always hated to be smoking along at a great groundspeed with diminishing daylight over the mountains and have to land to get gas when just 10 more gallons would have easily gotten me home with reserve. Despite Van's disclaimer in the RV8R on aux fuel, I think aux fuel is the owners choice. My airplane has Experimental on the canopy...
If you operate within Van's restrictions of weight and know what you're doing, I see no foul. I'll put the word out on your tanks.
See ya!


Rob Ray
 
Aux Fuel

Agreed on the fuel, I'm having a set of the sheared tips made into tanks & I'm told I can get 11 to 11.5 Gallons each. hate to see the bill on this project. I have thought of an extra 20 gallon rear seat fuel cell also. I'm getting close to Rocket money in a 1000 hour -4 with a slider, not smart. I did the Odessey battery, but it didn't last. With my C.R. it didn't have enough push after a few months of use. I purchased a new one and had the same results from day one on it. I went back to the old heavy Concord 35 and it spun up like a top. I like to keep the back seat empty, so the aft weight isn't a problem. Most of my local flying I keep it loaded with fuel for the mission & reserve only. On X/C I want all the fuel I can get, I like non stop.

Gary
 
Set of Safeair1 ER tanks for sale

I just got a set of Safeair1 tanks with my recent RV-4 purchase, however they will work in any RV I was told. I don't need them, any interest out there? They are unused. Send me any questions/offers.

Jj
 
RV-4 Engines & weight

Look at the FAA T.C. Data sheets and you will see the 0-360-A1A weighs just 9 pounds more than the 0-320-A1A. It generates more torque than the 0-320. My purchased -4 with the slidder weighed in at 1100 pounds empty. I have added tip tanks and A/P & removed interior & steam, so weight weighed the same. I did the small battery for about 6 months, but it gave out, from turnining 11.5 to 1 CR when hot starts took it's toll. I love the C/S prop for T.O. & formation, but it adds weight. If I wasn't in so deep $$$ on mine I would go for a lighter C/S prop. An RV-4 showed up at my house with main tanks of 59 gallons. I wish I had those with my tips, I love non stop trips.

I'm looking for a clean Cub, Champ or Taylorcraft if anyone knows of one for sale. email me @ gjslutz(at)adelphia.net

Bullet
 
avengingangel said:
since i bought my rv4 last summer i have
6 and oh ya that dipstick ive glued that for the second time this time itll hold
Click to expand...
I re-glued mine twice, when it still came apart I threaded it, yup! I know it's plastic, but I threaded it and used a threaded PVC coupling and it's still together after 500 hours flight time.
 
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