I would love to see someone move the fuel to the wings!
I think if the wings were permanently attached (like regular RV's) and the fuel tanks were where they belong, Van's would have sold a couple hundred more airplane kits by now.
This is one thing that I hope will happen.
If I get that far I will put the Fuel Tanks in the Wings, this is why I will build the Wings last.
If I sell me RV10 Empennage Kit my wife will let me get back to work on my 12
www.joesrv10.com
There's "experimentation", and then there's "evolution".
Anything significant like the powerplant and others that affect W&B substantially may be "legal" for EAB, but probably better done on other RV models than the -12.
Glad you shifted the thread Tony, I will add my 2 cents worth:
I can understand Vans approach, if I were he I would do the same thing. Safer figures for the breed means more sales and higher profits, and the bad things about RVs are almost soley due to "experimenters" altering the original designs. Out of consideration to Vans, that is why my aircraft bears not one reference to Vans, the name will not be on registration or AW certificates. If I crash and burn, it will not be connected to Vans in any way, nobody can decide to bring a lawsuit against Vans. Am I way off base here?
If you do that, where are you going to put the people?
The leading edge tanks on the other RV's put the fuel forward of the CG and the CG moves aft as fuel is burned. With the -12, the CG moves forward as fuel is burned.
I believe that if you put wing tanks on the -12, you will have a major FWD CG issue. With the people sitting so far forward in the -12, you will have to add some weight in the tail to offset the change. That or move the people aft.
What you are proposing is a slippery slope...
Bill the CG. Is an issue the engine choice and location of the battery and fuel tanks?
I have run numbers on a few scenarios that I think will work.
Until I have more information on alternate engines I am not sure that it will.
I will not do if the numbers don?t work, but I think they will
That?s why I will build the wings last.
The leading edge tanks on the other RV's put the fuel forward of the CG and the CG moves aft as fuel is burned. With the -12, the CG moves forward as fuel is burned.
I believe that if you put wing tanks on the -12, you will have a major FWD CG issue. With the people sitting so far forward in the -12, you will have to add some weight in the tail to offset the change. That or move the people aft.
What you are proposing is a slippery slope...
Out of consideration to Vans, that is why my aircraft bears not one reference to Vans, the name will not be on registration or AW certificates. If I crash and burn, it will not be connected to Vans in any way, nobody can decide to bring a lawsuit against Vans.
How about pulling the UL or Jab engine closer to the firewall, possibly moving CG enough to allow wing tanks? That would solve multiple issues discussed.
I considered wing tanks early on and knew it would not be possible with my build nor do I have the time to design/engineer/manufacture them so I quickly dismissed it One concern I had was the wing was not designed for the fuel load in turbulence.
One concern I had was the wing was not designed for the fuel load in turbulence.
Change, don, I don't understand why you purchased the Rv-12 when u want to change everything about it. Would it have been easier to design your own aircraft to your wants and likings and left Vans out of the picture. What school did you get your aero-engineering degree from, Vans did a great job with every aspect of the RV-12, that is why it is the most popular lsa aircraft on the market, my vote is to leave it as us.
I have a structural engineering background not an Aeronautical engineering background.
I believe the moment on the spar is less with the fuel in the wing then in the fuselage.
The rotational affect on the spar from the fuel in turbulence is above my pay scale. I will need help with this engineering if I decide to do this, the front and back connections are in sheer not moment this concerns me.
I have always been in awe of the wingtip tanks added to production aircraft - with no (or minimal) change to the structure. Would not think that would work out well, but it seems to.
Don I looked at tip tanks for the 12, the spar at that end of the wing would need a lot of redesign and on a hard landing would add a lot moment to the spar at the fuselage. Small tanks maybe, but not big enough to replace the main tank
Can?t wait to see your Viking Flying.
After all, is that not the start of Vans, remaking a proven kit into something he liked better?
.
...My $0.02 and it is only that, is that if folks finished their -12s in original configuration and flew them for 100 hrs before considering major redesigns, there would be a lot more happy campers, fatter wallets, and fewer structural and powerplant experiments in the works.
-Dan Masys
Occasionally, a sentence just leaps off the page. This one is worth repeating.
This could be said of RV's in general as well as the -12.
What would be the rationale for modifications to any experimental aircraft that would not include the RV12? Light planes have been altered many times. Zenith and Kitfox have tried almost every engine made. The Jab 2200 will prove successful on the RV12. Many modifications are a result of need, either cost, comfort or appearance (its all about lookin good). The Rotax is a wonderful engine but also the most expensive. Everyone cannot affort a firewall foward that is half the price of the aircraft. Numerous alternatives exist now and more will appear. Everyone cannot afford a Skyview with synthetic vision they will never use. Everyone cannot fly in 10 degree weather without an innovative serious heating system. To say that an experimental plane is fine as is means the designer likes it as is. Once you buy it, its not his anymore...change whatever works for you and get it signed off.
According to the NTSB, 48% of last year's EAB accidents were not by crazy EAB builders but instead by the "future owner". We need to quit concentrating on these innovators and pay more attention to where these finished aircraft are actually finding a home. Bonanza's are certainly more forgiving than a Lancair but if you want to go 300 kts and can't build a birdhouse...just buy one.
My thoughts are the 12 is a sweet airplane as is. The small exceptions that I believe are fine are adding 2" alt. and airspeed gages, Joe gore's hookup for the AOA, stick pants, a few clamps here and there to improve support of components, etc., etc. I am convinced a lot of good engineering went into this design , and I have no interest in making major departures from it. That being said I also believe anyone who wants to can do what ever they desire. including major changes. I just haven't yet found any reason to do likewise. I do enjoy reading about these adventures tho as well as commenting on them. Good luck to you folks in the experimental skunk works, and be careful.
Dick Seiders
So how do those aftermarket tip tank makers get by wth it on factory built planes?
What if wing tanks were located behind the spar thus the CG would be slightly behind cg and allow for fuel line disconnnects in cargo area?This would also affect the weight and balance less than the standard fuel tank.
While airborne, the wings will carry the extra load of fuel just fine. The concern is stress from hard landings. When the wheels hit the ground, the inertia of falling fuel in the wings will put a large load on the wing-fuselage junction. Are the wings strong enough? This is a question for an engineer. There is more to consider besides weight and balance and "will it fit".
Joe Gores
Or if some one will let me jump up and down on there wing I could test it to over 3Gs
Wing Tanks 12Gal 75lbs each + the tank
Tony, quick, close the poll and call it a draw!
Ha! Too late, it's moved on again!
Pretty even result though. I think both options are basically correct. The -12 is an experimental aircraft, and so is open to modification. However being such a tightly integrated design, shoe-horned into a quite restrictive set of performance parameters, it is probably not a particularly good candidate for major experimentation.
You think it is probably not a particularly good candidate for major experimentation.
For some that is just like waving a red flag in front of a bull. A challenge.
Rainier
The poll speaks for itself
You think it is probably not a particularly good candidate for major experimentation.
I think it is probably a good candidate for major experimentation.
Some ideas will not be so good.
And some ideas may improve the performance
Only time will tell
Good luck to all that try