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Looked at an RV, a few snags came up, how bad are they?

EasyFlyer

I'm New Here
Greetings Everyone,

I've been looking at a few RV4's that I'm interested in purchasing, and finally came up on one that is a definite maybe (1st one I may consider buying anyway)

A few things came up that I am not sure about.

#1, un-even tire wear. The outside edge of the left tire is worn down a lot more than the rest of the tire. The tires are quite worn, but the outer edge is bald. Does this signify bent landing gear? bad alignment?
The log does show the landing gear being replaced in the past...
Is this significant?

#2 This one has me worried and made me not make the deal, at least not yet.
During slow flight only, nose high, I could smell fuel in the cockpit. Not on the ground, not during level flight or climb out, only during slow flight. Once the nose is level, the smell would clear out quickly.
On the ground, could not find a leak, could not smell anything, except a bit in the intake?
What could this be? enough to walk away?
Carburetor problem stuck float? the engine ran just fine the whole time.
Cabin heat was on (thats probably how the fuel smell got into the cockpit)
Checked the fuel pump, lines, fuel tank vents, nothing, no fuel, no smell.....

Thoughts? Ideas? Suggestions?

Thx!
Easy Flyer
 
My old RV-4 positively ate the outside edges of the tires. When I jacked it up and put a straight edge (a six foot aluminum extrusion from the home store) across the axles, both wheels were way toed out, whereas they should be straight or just barely toed out. Not toed in like on like a car, toed out. The solution was to remove the motor mount, have the bolt holes welded over, have plugs silver soldered in the gear legs, and re-drill. Sound like fun? The plane was lots easier to land with the gear properly aligned...

You can probably chase the gas leak till the cows come home. On mine, I had to build new gas tanks and match-drilled the holes. Also fun.

No matter how good the plane, you'll probably find things wrong with it. The gear problem is, in my book, disqualifying (and there were no tire replacements in the logbook).

Ed
 
All spring landing gear planes - certified or experimental, are going to have un-even tire wear on the outside edge. When the gear is un-loaded the outside edges hang down lower, and therefor take the brunt of having to spool the tire up from 0 rpm to 70mph in a fraction of a second. If both tires were worn and just the outside edge is worn more then you have nothing at all to worry about.

The fuel smell in slow flight is also not a show stopper as long as there is not a fuel tank leak. It is most likely related to the vent configuration. If the plane has forward facing vents, they pressurize the tanks during flight. When you slow down and change the angle of attack the tanks can vent out any fuel that has accumulated in the vent line. It will take a lot of experimentation to see if it is this or a leak somewhere.
 
Have to agree with the last post about the tire wear.
Probably not an issue. I log all my landing so have a good idea what wear I am getting on the tires

Fuel smell could be a lot of things. Pull the wing root and see if the tank is leaking at all.
Jack
 
Tire wear on the left main tire is often from people scrubbing that tire on takeoff. Roll in some right aileron to counteract the torque on the takeoff roll and that wear greatly diminishes.

The fuel smell? There are a few (less than 12) fuel connections between the wing tanks and the fuel delivery device. Checking them is fairly easy, and if you find a bad one, it is easy to fix.

The other possibility is a leaking fuel tank. Check carefully for that. The repair can require a lot of work.
 
Thanks for the quick reply everyone,

The tire wear is a lesser issue (the plane is not perfect, there are other little things here and there, I'm not expecting perfection by any stretch, I just would like to get a good solid plane and work out any small things that may come up)

Only the left tire is worn out on the outer edge, so maybe just that gear is out a bit, or like suggested the owner rolls that tire on take-off.

The plane does have forward facing fuel vents, I did not see any leaks after landing. One fuel tank was re-sealed by the owner, the other was original, I did not see any evidence of a leak when I was inspecting, but I did not remove the wing root fairing. The tanks were super full before take-off (up to the filler caps) and if there was a leak at the wing root, I think I would have smelled it (enclosed t-hangar) or saw something?
But nothing, no smell, no evidence... Only during slow flight (& on final)

Easy Flyer
 
Full tanks

My -4 will get a wiff of fuel in the cockpit when the tanks are full and I do less than 1G. I think a small amount of fuel is vented from my vents located on the belly forward of the spars ( per the plans). The vapors probably come up through the tail.

My gear legs were factory drilled and i get uneven wear. Just the way this gear is.

All airplanes are different for sure

Cm
 
Depending on the age of the build, you may have sloshed tanks. You might want to determine that before consummating any deal------correct fix is a bit of a pain.

Lots of info if you do a search.
 
This is definitely an early RV4, '84 s/n 66.
I looked inside the tanks, did not see anything floating around, no white stuff/chunks floating around. The older tank had plenty of this black/tar looking sealant inside on the tank walls, but nothing loose.

Easy Flyer
 
My RV6 wears the outside of the tires first - always has. I just rotate them once I get down to a minimal tread pattern. No big deal to me.

As for the fuel smell, I strongly suspect it is related to venting at the high AOA needed for slow flight. Pull the wing root fairings off and look for blue stains (100LL) or carmel stains (auto fuel). if you don't have those, then again, not a show stopper. Black tar could be anything - but proseal is commonly used and would match that description.

Good Luck
Don
 
#1, un-even tire wear. The outside edge of the left tire is worn down a lot more than the rest of the tire. The tires are quite worn, but the outer edge is bald.

The fact the tires are about worn out is a good sign. This means the outside wear on the left tire is not significantly worse than general wear. If the tires looked pretty fresh and the outside was worn, that would indicate significant mis-alignment. What you are seeing is very common with RV-4's and -6's.

#2 This one has me worried and made me not make the deal, at least not yet.
During slow flight only, nose high, I could smell fuel in the cockpit. Not on the ground, not during level flight or climb out, only during slow flight. Once the nose is level, the smell would clear out quickly.

As others have stated, this is almost certainly normal fuel venting at high AOA.

Enjoy your new RV!
 
If the tanks are near full, then some can get into the vent tube and come out over the bottom of the fuselage which you can smell in the cockpit.
 
Agree with others, fuel vent issues unless of course there is an obvious leak.
Try reproducing the situation as you describe then side slip the plane whilst in that slow flight phase. Not too much slip say a full balls width out on the slip indicator assuming you have one, just make sure you keep the power up due the extra airframe drag, if the smell goes away then the vents are the culprit👍
 
Agree.

I agree as well. The tires wearing on the outside edges is standard for the RV tires. We do the take-off and turn around to put the inside edges on the outside when needed as well. The fuel smell in one you just have to track down, Most of the fuel leaks from the outside at the tanks, you will not smell while in flight. The fuel lines inside the cabin can be checked for leaks. The vent lines or a good suspect with the description that you have given. We have ours per the older style, where the 1/4" lines go down and out, then turn to the front, into the oncoming air. Many of the installations have gone to the flush, surface type vent. They have less drag, but the opening is closer to the cabin skin and may be able to let vaper into the cabin. With a new aircraft you are going to want to recheck everything two or three times anyway. If these are you only two concerns with this aircraft, you are in good graces with this pick. You will always be fixing something as you go, it is part of having your own RV. Just two pennies for thought. R.E.A. III # 80888
 
Tires... as long as it lands fairly predictable and manageable.

Fuel smell... mechanical gauge? Check the lines to the fuel gauge. Look for blue or yellow streaks on the bottom to indicate fuel leak.

Tinker
 
On the stock fuel valve there can be some seepage from around the handle shaft. Typically happens with older valves when the tanks are full. It can simply be a matter of taking the valve apart and perhaps adding a new O ring and lubing the assembly. Although not a difficult job, the body of the valve does not have to be removed from the airplane, you might get a mechanic to check it out. Before plunking any money down you should have a pre-purchase inspection by a qualified mechanic.

Call me at 519-281-1369 if you have any questions. I live in southern Ontario.
 
Thank you everyone for your offers of help and thoughtful insights, I have given it a great deal of thought and decided to hold off on this particular RV4, just too many little problems (lots of other things I did not mention, I was asking about the parts that I was really not sure about) this seems to be a case of death of a thousand paper cuts.

I will keep my eyes and mind open.

If anyone knows of a RV4 (or reasonably priced RV6) for sale in Canada, I'm all ears!

Thanks!
Easy Flyer
 
carb maybe?

I had an in flight fuel smell in my 9A..looked all over for a leak in the tank or lines. I was just sure thats where it had to be.. Couldnt find it. And like you..nothing on the hanger floor or under the wings.
Then, while washing the plane, I noticed small blue streak on the back of the nose gear faring..up high next to the cowl.
I pulled the cowl and found more blue stain than I liked around the top of the air filter and on the carb..hmm.. but no fuel leaking out static..
turns out, the carb accelerator pump was leaking it only happened when you moved the throttle of course..and it was big leak.
pulled the carb and replaced all the gaskets including working over the pump...
That fixed it. So dont discount the carb. check it over real good, and have someone get in it and pump the throttle a bit while you are looking at the carb.
 
You may be onto something there, after landing and looking the plane over, the only place I could smell fuel was in the air intake, so maybe the carb has some sort of leak, not sure.

I have decided to pass on this particular RV4, it was a worth while trip to go and look at it, but I'm now waiting until spring/summer '19 to resume seriously looking for another RV.

Having read many times that it can take a very long time (years?) to find your own airplane, I can now see why. Hopefully it won't take that long, and I think I will expand my search to include other airplanes, none seem to come close to an RV in the fun factor, but if it means the difference between flying and not flying....

Easy Flyer
 
I see you decided to pass, but I will tell you my experience in finding a -10.

1. The first one I looked at had a G500 panel. Great paint job, a bit worn interior an it was lower priced.

What bothered me was that it had a 300 HP engine on it and it looked like the builder had done quite a bit of wrangling to make that work...and it was heavy.

I Passed.

2. Next one was a beautiful build with a beautiful glass (VFR) panel.

But, the builder did not disclose that he had retrofitted the engine to be injected (from carb). That bugged me.

It had a three blade prop, and was beautiful, but it was fixed pitched. The builder was evasive on giving me speed test numbers.

Last straw was that I asked for a list of all panel functions (parts and pieces) and he told me one feature was there, but in the panel pictures, it wasnt.

Bottom line, I got a weird feeling and I bailed...but it was a really pretty airplane.

3. Last one, the one I bought, had been sitting unflown/unmoved/unstarted for two years. I was worried about engine corrosion. A call to the engine builder (Penn Yan) told me what to look for internally. It all worked out and I bought the plane. It was beautiful inside and out.

While in training I noted a strong fuel smell on climb out.

I continued to notice that smell for close to 6 months.

Ultimately, I found, by taking the fuel system access cover off, that the outlet on the boost pump had a small fitting leak and it was pretty obvious that it was unsafe (lots of blue dye in the channel).

I simply tightened that fitting and all was resolved.

Bottom line, fuel smells, IMO, are a big deal.

Through pre-buys....also a big deal.
 
Fuel Smell

I was getting a whiff when I pushed the throttle up. The vent in the fuel injection spider was dumping fuel. Have sent the entire fuel injection system to Airflow Performance for overhaul. Hope it fixes the whiff.
 
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