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RV-3 Fuel Tank

M

mmcdonald

Active Member
I had an RV-3 empennage kit and just acquired a wing kit for an older RV-3.
The wing kit leading edge is assembled without fuel tank which gives me
2 options. Tear into the wing leading edge and build fuel tanks or go with
a fuselage tank. I like the KISS principle, but is the fuselage tank a big
no no. Does Vans even supply a fuselage kit with fuel tank, On their
fuselage order form I noticed there was not an option for a fuel tank.

I?m aware of the 4 gallon penalty and spar mod issues. 26 Gallons seems
like enough fuel and I prefer a lot of straight and level flying. I like
the gravity feed option I think you get with the fuselage tank.
 
mmcdonald said:
I had an RV-3 empennage kit and just acquired a wing kit for an older RV-3.
The wing kit leading edge is assembled without fuel tank which gives me
2 options. Tear into the wing leading edge and build fuel tanks or go with
a fuselage tank. I like the KISS principle, but is the fuselage tank a big
no no. Does Vans even supply a fuselage kit with fuel tank, On their
fuselage order form I noticed there was not an option for a fuel tank.

I?m aware of the 4 gallon penalty and spar mod issues. 26 Gallons seems
like enough fuel and I prefer a lot of straight and level flying. I like
the gravity feed option I think you get with the fuselage tank.
Click to expand...

I think the fuselage tank is good for 24 gallons. It'll limit your options for panel choices as there is very little depth for instruments. I've flown both and could never get used to looking at 24 gallons of fuel sitting between my legs.
YMMV
Tom
RV3 x 2
 
Pros and Cons

I fly an old-school -3 with the fuselage tank.

Max cross-country range is about 2:45 hrs (with reserve) - enough for me - I plan for 2:30 legs. Simple fuel management - no tank-switching required. Elevator trim changes only since the tank is on the centerline. Have to be very careful when filling the tank to avoid a gusher overflow because of the oval tank cross-section - the last inch will fill in an instant.

One drawback is that the tank sits behind the panel, so instrument depth is limited - I think mine is about 4.5 inches. Most instrument depth dimensions are given without including space required for the connector. I had to move my panel back a half-inch to squeeze in a Trutrak ADI and still had to make some mods to the pitot connection on the back. Glass instruments tend to require less depth. Not enough depth behind the panel for most radios and transponders, so you see these mounted in a side panel or in a center console below the tank, behind the stick.

I think I've read that wing-mounted fuel doesn't count toward the gross weight limit for aerobatics, but you should check on this.

...Joe
 
Last edited:
Tank Supplier Unknown

Reiley...

I didn't build the plane - it is 1982 vintage, built by Alan Tolle. I don't have the construction logs, so don't know if the tank was furnished by Vans or custom made. The plans give the dimensions and details.

...Joe
 
Space behind the panel was something I had not considered and a fuselage tank from Vans lists for $950.00 Would rather not limit instrument options, and I can actually save money on parts, labor another story, will go with wing tanks. Should be fun cutting leading edge skin off, drilling out some rivits, working with pro seal, and all that good building stuff.

Are wing tanks for a RV-3B and a RV-3 different?

I think I read some were Vans does not support the RV-3 wing tank.
 
I think you will be on your own.

mmcdonald said:
Space behind the panel was something I had not considered and a fuselage tank from Vans lists for $950.00 Would rather not limit instrument options, and I can actually save money on parts, labor another story, will go with wing tanks. Should be fun cutting leading edge skin off, drilling out some rivits, working with pro seal, and all that good building stuff.

Are wing tanks for a RV-3B and a RV-3 different?

I think I read some were Vans does not support the RV-3 wing tank.
Click to expand...

To my knowledge, there are no wing tanks for the RV-3 wing. The RV-3B wing is completely different in its construction from the spar on out. You will have to engineer your own solution which would cause me concerns as the RV-3 spar is not known for being overly built as it is. Perhaps you can find someone who has done a conversion of 3 wings, but most have replaced the wings with the 3B wing to get the advantages of no limitations or modifications and wing tanks.
 
My first RV3 built in the 80s had wing tanks as an option. I know of one early RV3 that had the whole leading edge as a wing tank. Pretty sure that was a very early model with the 1/8 rivets in the main spar. He posts here once in a while. Still, contact Vans.
Tom
RV3 x 2
 
RV-3 Wing Fuel Tank

Spoke with Vans this evening and was told wing fuel tanks on an RV-3 are not supported, and the RV-3B tanks are different. Will need to field engineer
a set of tanks based on general knowlege of RV construction of other models and the RV-3B configuration.
 
RV-3 Fuel

Back in the day you could order the RV-3 kit with fuselage fuel or wing fuel.
I went with the factory welded fuselage fuel tank to KIS; gravity feed to a mechanical fuel pump to carb.
I believe I have most parts for wing fuel (ribs, skin, aft wall) for the old style wing; if that is what you are after and Van cannot support.
Don
 
Timely....

Hello all,

I'm brand new here and this is exactly the first item I wanted to read about. I've just tentatively bought an RV-3 project. It's already flown but flipped over. Since then it has changed hands a few times and the wing tanks became one of the projects. It was originally a fuse tank. The current owner has the wings off and one new wing tank almost complete. I would really like to use that tank, and wing so I can save a ton of $$ over a new 3B wing and retro kit. It needs the spar mod too which I can easily do while the wing is off.

So here's my question, what was the difference in the wing while Van's was offering both options? Seems to me that a wing tank added to an old wing would be okay since it was an option at one time.

I have a long (30 hour) drive to make to pick this thing up but want to make sure I'm not wasting my time. For ti to eb worthwhile, I need to be able to use the old wing.

Incidentally, I will have the old Fuse tank and if and when I get it home, I will sell it if anyone is interested.

Thanks
Chris
 
Wing Fuel Tank

Chris,

According to several posts, Vans offered the wing fuel tank on the RV-3.
I called Vans earlier this week, and they indicated if you wanted a wing
fuel tank for an RV-3 you were on your own.

Spar rivits varied in size fro 1/8 to 3/16 of inch. There are separate spar
mod change notices based on spar rive size.

The fuse tank limits space behind the instrument panel which is something I don't care for. I would like to leave my options open when configuring my panel.



Mark
 
My RV3 plans number 11170 is what I would call an RV3A wing. The plans show details for the wing tanks. If someone wants a copy of the tank plans let me know.
This is not a recommendation to reverse engineer anything.
Tom
 
Thanks Mark and Tom,

I think I have a 3A wing... but this plane was built with the fuse tank originally. One of the subesequent owners went to the trouble of buying a wing tank kit from VANS for it, so I hope it will be a legit change. Van's told me the same thing about being on my own. I don't mind if they don't want to support it, I just don't relish the idea of being a test pilot. Interestingly, the project comes with a completed new spar, so I guess I could start all over - arg. I know that I will have to do spar mods though...not sure which one.

I will watch this forum with great interest to see what else develops amongst you other 3 builder.

Cheers
Chris
 
MAGNUM
Do your wing spar laminates have a single line of 3/16 rivets or a double line of alternating 1/8 or 5/32 rivets? If it has the double line of alternating rivets it was not designed for wing tanks. Hope this helps.
Tom
RV3 x 2
 
Hi Tom,
I have a photo of the wings along with a spare set of spars. It look like two rows of rivets to me, but Theyu don't seem to alternate... I dont' think I can post a poto here but I could email it to you and maybe you'd be able to tell which it is?
Thanks
Chris
 
Chris,
The Type two spar was used for wing tanks. It has 3/16" thick strips laminated with 3/16" rivets. There were some other changes too, the ribs in the wing root area are on about 3-4" centers and the rear spar to fuselege attach area was changed.
Bill
 
Magnum67 said:
Hi Tom,
I have a photo of the wings along with a spare set of spars. It look like two rows of rivets to me, but Theyu don't seem to alternate... I dont' think I can post a poto here but I could email it to you and maybe you'd be able to tell which it is?
Thanks
Chris
Click to expand...

Sounds like the first generation wingspar. I wouldn't do it.
Tom
 
Hey Tom,

I'm a bit weary about it... and want to make darn sure of what I'm getting. The vendor is taking some more photos and checking to see what we've got. I did some other checking though and came up with this....

The serial number is 10015, and on the C of R and airworthiness it is listed as an RV-3A. Does this define what wing type it is? Or could it still be either? In the mean time, waiting on more details from the vendor - with fingers crossed.

I suppose that the project will not be worth what I am paying if the wings turn out to be the old ones....arg.
C
 
I've been told Vans kinda jumped around with his serial numbers in the beginning, not sure if you can tell. If there's two rows of rivets and 1/8 laminates its a first generation 3. Somewhere along the way he redesigned the rear spar attach also, that would be something I'd want to look at also.
Tom
 
Whew....

With regards to the question of which wing, well it looks like I'm okay, singe row, large rivets... a huge relief! Onwards and eventually, upwards! Thanks to those who made me aware of the differnt types...

C
 
Tank Plan

RV3 Pilot said:
My RV3 plans number 11170 is what I would call an RV3A wing. The plans show details for the wing tanks. If someone wants a copy of the tank plans let me know.
This is not a recommendation to reverse engineer anything.
Tom
Click to expand...

Tom would like to get a copy of Type II wing plan for the fuel tank and spar.
Any suggestions on logistics for sending me a copy?

Mark
 
Rats....no Double rats....

Okay, it seems the inital ussumption that my wings were the single rivet line rather than the double alternating rows was wrong. They are the old ones. Rats!

So, I"m back to my original question. Someone said if they were the old style they wouldn't do wing tanks. Why? Whoever owned these wings prior planned to do just than and even made a mod the spar. I have a photo showing a 1/2 inch wide strap that joins the top spar cap to the bottom. He's done it in a couple of places. Since I have no idea what the proper fix from Van's looks like I can't be sure if this is it or if its the builders own "engineering".

I wish I could post a photo somewhere so someone could look and say yea or ne.

The deal just isn't so great if I have to buy a whole new wing kit. Arg.

Thanks for the input!

Chris
 
Magnum67 said:
Okay, it seems the inital ussumption that my wings were the single rivet line rather than the double alternating rows was wrong. They are the old ones. Rats!

So, I"m back to my original question. Someone said if they were the old style they wouldn't do wing tanks. Why? Whoever owned these wings prior planned to do just than and even made a mod the spar. I have a photo showing a 1/2 inch wide strap that joins the top spar cap to the bottom. He's done it in a couple of places. Since I have no idea what the proper fix from Van's looks like I can't be sure if this is it or if its the builders own "engineering".

I wish I could post a photo somewhere so someone could look and say yea or ne.

The deal just isn't so great if I have to buy a whole new wing kit. Arg.

Thanks for the input!

Chris
Click to expand...

I don't know what the intent of these bars was, but it is not the required mod. for Type I spars.
The type I mod. uses aluminum angle installed span wise on the upper spar cap only (the one loaded in compression during positive "G's"). If you are interested in modifying your wings rather than building later version wings, call Van's. They will give you a free kit and drawings to properly make the modification.
While you are at it, you should confirm that the root rib has either been re-enforced or changed out to a heavier thickness material (this was another change made to Type I spar wings).
 
Fuse-Mounted Tank

Contact Vans for the wing mod info. You could just go with the fuse-mounted single tank and design the panel around the space limitation. Glass generally doesn't require the depth of steam gauges. Build a center stack below the panel for radios, xponder, etc. Or mount them on the side. You won't have quite the range because the fuel capacity of the single tank is less than the two wing tanks, but the speed still gives you enough leg distance for cross-country. Who needs more than 2.5 hours in a cockpit anyway? Simple fuel management with no tank switching.

...Joe
 
Type I wing with fuel tanks- seems like a plus.

Chris said...
Someone said if they were the old style they wouldn't do wing tanks. Why? Whoever owned these wings prior planned to do just than and even made a mod the spar. I have a photo showing a 1/2 inch wide strap that joins the top spar cap to the bottom. He's done it in a couple of places. Since I have no idea what the proper fix from Van's looks like I can't be sure if this is it or if its the builders own "engineering".

I wish I could post a photo somewhere so someone could look and say yea or ne.

The deal just isn't so great if I have to buy a whole new wing kit. Arg.

[/QUOTE]

Chris and Mark
After reading the thread from last winter, based on the documentation on hand and what 2232B looks like, seemed like a good thing to reopen this thread.
2232B has type one wings (1/8 inch spar laminate, 1x1x1/8 rear carry through) and I have wing tanks (13.5 gal each). I don't see a problem with type 1 wing tanks, in fact, it seems like a good idea. Any weight moved from the fuselage to the wing, should reduce loading of the spar during the higher G manuevers that the type 1 spar typically have failed under. This isn't my original thought on my part. Although not consistently stated (there is a frustratingly amount of discrepant info) the official position in the CN-2 document (1997-98?), is that for aerobatic flying, weight in wing tanks is not included in the 1050 gross, unlike weight in a fuselage tank. Furthermore, CN-2 on page 4 offers instructions on what to do with a type 1 spar that has removable wing tanks. Wing tanks for type 1 spars are clearly an option. If you've got a old set of type 1 wings and the parts to add wing tanks go for it. Building these up would allow you good access for the wing mods and you could pay special attention to the CN-1 "Inspection Points" and CN-2 "condition inspection" items. When done, you'd have a 6 g positive, 3 g negative, 1050 lb plus fuel airplane. That said, I think there still might be some reasons to do a 3B wing. If you feel you need the factory support that buying a new wing might bring, or want a even stronger wing than a fully inspected and updated early wing, then go for it, but I hope you don't feel compelled to keep a fuselage tank because wing tanks aren't "OK" with the old wing. That would be incorrect.

(thanks Randy L. for links and summary regarding the RV-3 wing).
best regards
Stan
 
Stan,

Thanks for the post regarding the Type 1 wing. I plan on using the old wing, installing all mods, and keeping the build very simple except for installing
fuel tanks in the wings. Currently working on empenage HS.

Better go to basement and start working!

mark
 
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