Fuel Tank Capacity Increase RV-7/7A

[Willem Botha]

I would like to increase my Fuel Tank Capacity with approxm 20 US Gal. Will be starting on my Quick Build Wing Kit on RV-7A this week. Anyone with experience in this regard?

 

[rhill]

http://www.vansairforce.com/community/showthread.php?t=64850&highlight=nose+wheel

Try this link. The A gear is at the upper limit of the envelope on the 7a and 9a models a little less on a 6a right out of the box.
Mic had added long range tanks to the leading edges as well as a big engine/metal prop,add to that 20 gals of 100LL and tanks&pumps,
you got one Fat RV,CG placement of that weight will push the nose gear right over the edge. Something to consider.

 

[pierre smith]

Hi Willem...

...would an extra 10 gallons do the trick?

If so, the HW tanks provide 5 gallons per side and are a long, aluminum tube that fits in the existing lightning holes in the ribs and are filled at the wingtip.

The CG change is negligible since they're essentially, on the CG.

Best,

 

[[email protected]]

not a casual thing to get 20 extra gallons...

like pierre suggests, the 9 gallon hotel whiskey system is suited for retrofit or a quick build wing... if you want more fuel you will need to remove the outboard leading edge and design your own extra tank and transfer system... quite an effort that should not be lightly entered into.

here is a link to the hotel whiskey system: http://www.safeair1.com/HWA_RV7-8.htm

 

[pierre smith]

On second thought...

..some of the Harmon Rocket guys have taken one wing tank skin and cut it in half and then add one half to each original tank, giving you close to 60 gallons.

Best,

 

[diamond]

I'm just curious how Vans views the use of these HW tanks. I know they come highly recommended by a number of respected RVers, but is there any compromise in the integrity/strength of the aircraft by using these?

 

[Kyle Boatright]

You'd have to call Van's, but *generally* adding loads along the span of the wing doesn't cause wing problems. For instance, in many Bonanzas, Comanches, Navions, etc. you get a gross weight increase if the additional weight is fuel in the tip tanks.

The issue you eventually get into is gross weight and how much weight are you applying to the landing gear.

 

[airguy]

You'd have to call Van's, but *generally* adding loads along the span of the wing doesn't cause wing problems. For instance, in many Bonanzas, Comanches, Navions, etc. you get a gross weight increase if the additional weight is fuel in the tip tanks.

The issue you eventually get into is gross weight and how much weight are you applying to the landing gear.

In flight, yes - but on the ground that additional wing weight adds to the spar bending moment at the fuselage - so ground ops and landing with additional win fuel will be more risky and you need to consider that.

 

[vk6ad]

Extra fuel

Hi guys

I think the more serious concern is the increased moment of inertia about the yaw and roll axes which will adversely affect spin recovery.

Cheers
Phil
Perth Australia
RV7 wings

 

[Fred.Stucklen]

I constructed wing tip tanks similar to those that Jon Johannson used to sell through Van's website (not avaiable anymore). I did change the plumbing from what Jon had done as it didn't seem to work properly all the time. My tip tanks added 9.5 gals per side for a total of 60 gals...
And this is the second RV that I've done modified this way. There are at least two RV-7A's and an RV-9A that have this arrangment in the New England area... No issues to date with over 1500 Hrs total time...

I would like to increase my Fuel Tank Capacity with approxm 20 US Gal. Will be starting on my Quick Build Wing Kit on RV-7A this week. Anyone with experience in this regard?