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External fuel tank

This is why I love experimental aviation...it's the folks that don't wait on someone else to invent something or market something...they just go out and do it themselves.

Practical or not, this tank is cool.
 
Thank heavens it's not really a 'drop' tank, though. Can you imagine the liability, not to mention the bad press for GA, if we start dropping fuel on the ground-pounders?

More seriously, I didn't see anything about plumbing requirements; fuel pumps, etc. but it sounds like a fun idea.
 
Drop Tank Plumbing

Thanks for the feedback.

On Plane in the video, fuel goes from each side to the Andair valve and then to the gasalator. Electric pumps drive the fuel to the engine from each "drop" tank individually. No attempt has been made to design a fuel flow path for a drop tank on an RV. The tank itself was modeled after an F-86 using CAD CAM and a three axis foam milling machine to create a male plug. Some work was required in surface finishing of the plug so that it was suitable for making a female mold. What I find interesting is that the same process can be used to make any size or shape object that one might want to carry under ones wing.

Tom Hunter
 
I just came across Tom's drop tank video;
My RV-8 isn't flying yet, but it is at the airport. I'm due to install the fuel lines, and thinking about the possibilities.
I'm wondering about the weight carrying possibilities of the wing tie down fittings on the wing spars?
It's not a bad location, so some supplimental plumbing and additional structure...
Surely I'm not the only one who has thought of this?
 
The Hotel Whiskey tanks mounted internally are a much cleaner solution and hold the same fuel quantity with no drag.

Best,
 
OK;
Ground detachable, low drag external Fuel tanks.
I was trying to reduce the A/C weight when the capacity is not needed.
These tanks seem safer than a fuse mounted aux tank, with better span loading and CG.
 
Sure;
Every modification has an effect(s).
Internal wing stores have many of the same, as in position of added mass, changes in structural stiffness etc.
That's not a prohibited thing, it's something to be aware of.
Flying with additional payload, of external stores will change the characteristics of the A/C, thus the mission. The aircombat movies always start the grand melee with "Drop Tanks!!". With that, the plane is converted from a long range aircraft to a combat aircraft.
I this case, tanks change a sport aeobatic RV-8 to a long range cross country cruiser, or pods could carry Christmas gifts for grand children.
No whifferdills with these attached.
Flight testing required.
Why do we build aircraft anyway???
 
The problem with drop tanks is that they are really only useful when you can drop them. I was lucky enough to do most of my military flying in clean aircraft or only 1 centerline tank. Other squadrons were amazed at the range we could get with a clean aircraft. Out fuel burn was always less. The extra drag of the tank eats up the extra fuel. Its not uncommon to only net half the gas carried unless you jettison the tank as soon as its empty. Thats not going to happen on a RV. The extra fuel burn from the drag is going to get expensive with 5 dollar a gallon AvGas.

Some of the F16 guys on here might be interested to know that the Navy guys flying the very low drag F16N would fly from San Diego to Oceana VA nonstop many times without any tanks. They went right up to 47,000 feet and throttled way back to something like 800lbs an hour fuel flow. Of course they not only had no tanks but no pylons and fewer antennas. The gun was also removed and the had the lighter A model avionics package with the big engine. The aircraft was was almost 2000 lbs lighter then a normal F16. They brought 5 Air Force guys over from Luke to help transition the Navy guys to the aircraft. They were flying with 2 tanks, pylons and the smaller motor. They never wanted to go home!!!! The Airforce had to come and drag everyone back to Luke.


George
 
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If someone is really interested in one, then get a copy of this video.

Tape 4, making fiberglass molds.

http://www.ar-5.com/vidkit96.html

Mr. Arnold shows step by step how he built a wing mount cargo pod for an RV that uses the wing tie down.
 
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Carl;
I'm O.K., those were good points to start the discussion.
George has a good point too, you just can't beat clean & light.
Maybe I'm just stirring the pot after seeing Tom Hunter's video demonstration of his excellent product.
I've seen a large pod set on a Longeze at KRNT, I think it was the ELLISON injector guy's plane? But those were dry stores pods, and maybe not removable.
RV8Riveter; Thanks for the link!
 
At one time, external pods were available for RV-4’s and -6’s but not through Van’s. As far as I know, they are no longer available but someone else might have better luck searching for them.

Here is a picture of them installed on a -4.
rvpods.jpg


A friend has a pair for his -6 and they are strictly external storage pods but I’m sure they could be modified to hold fuel.

They are attached via two screws/platenuts in the top of the wing and the third bolt goes where the tie-down ring normally goes.
 
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That's a very nice picture of a well accesorised RV-4...:D
I suppose it could make a camping trip a bit less uncomfortable, even if they are too small for sleeping bags!!
Thank you, those pods look great.
I hope someone else who has seen these or with experience could add a comment?
 
I know this thread is super old, but I’m wondering if anyone has seen anymore external wing pods like the ones above. I’m looking to add some to my -8. If someone has molds and the ability that saves me lots of time and experimenting. If not, I’ll have to get started!

I’m strictly looking for wing pods like this, not wing tip storage!

Thanks
 
A guy in our EAA chapter made tip tanks for his Cavalier using Van's pressure recovery wheel pants. It's been suggested here that they might be a good starting point for 'drop' tanks, too.
 
When I first flew my RV-8, I had a Mazda Turbo Rotary engine. It was so loud (even with the turbo to mince the exhaust!) that I had to add a muffler.
I installed 4 large plate nuts in the two keel bars, which are still there after I changed it out to a Lycoming O-360.
I 'could' add a single tank or cargo pod under the fuselage, or maybe a Vetterman fuselage fairing...or drag reducing auxiliary fairing pod....:confused:
Right now I'm doing a rather extensive '4th year annual' with upgrades (rebuild the brakes, add oil filter, new Dynon EMS, tailwheel bits etc.)
But that external fuel tank project is 'Always On My Mind'... :rolleyes:
The 'Slipper tanks' on WWII British aircraft are interesting, and I think are the inspiration of the Arnold tanks.
 
I know this thread is super old, but I?m wondering if anyone has seen anymore external wing pods like the ones above. I?m looking to add some to my -8. If someone has molds and the ability that saves me lots of time and experimenting. If not, I?ll have to get started!

I?m strictly looking for wing pods like this, not wing tip storage!

Thanks

Here is the video from Mike Arnold on making the molds for the RV travel pods. It would be great if someone had these molds!

https://www.youtube.com/watch?v=H5A7_oPAw9c
 
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