shawnkappner

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Guys,

Odd request but I want to get in an 11 hour endurance flight and need about a 3 gallon custom tank. Anyone know who I might see to make one up for me???

Big_Bird

My Feedback: (1)

How custom? What's it go in? You might find a 3 gallon plastic gas can at Walmart or get a 5 gallon one and fill it 3/5 full. Most larger cities have custom welding shops that cater to walk in business but they aren't cheap.

Ken

ifixairplanes

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maybe you should by a gas can from walmart and build your plane around it.

sean

BasinBum

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From what I understand the key to endurance flying isn't all about fuel. Highly effeciant motors are the key. Do some research on the transAtlantic flight to see what Maynard used.

Joe Ortiz

My Feedback: (75)

Also make room for a car battery

Dago Red

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link up fule tanks, place them in the wings and in the fus, us bladder tanks as well, your gonna need a huge plane to hold 3 gallons

shawnkappner

My Feedback: (40)

It will be going in a Curtiss Robin 99". Actually I just did some testing over the weekend and I will only need about 2 1/2 gallons. I do need a custom tank built either out of fiberglass or aluminum or ???. Walmart tanks are too wide. The plane is already framed up so I can't build the fuse around the tank.

Two 3000 milliamp Nicads will do the trick as far as the batteries go.

Thanks Guys

Shawn

Highflyer

like Basin Bum said its all about effieciency...the transatlantic model was running on Coleman lantern fuel. I'm not sure of the modifications if any are recquired to run this fuel in an engine but i would definetly look into it. fuel consumption would be considerabely less. I cannot even imagine the wing loading on an airplane weighted down w/ 3 gallons of fuel. You would need a pane with a much larger than 99" wingspan. Also did you ever consider how much the CG will change after most of your fuel has been burnt off? It will almost certainly change to an unflyable condition. Also, what will you use to power your radio equipment? No way a standard size battery would last 11 hours unless you had about 10 of them and that would add alot of weight too. You could rig up an alternator like was used in the transatlantic flight but that would probably be very expensive. I'm not trying to kill your idea or anything but a near 1/4 scale aircraft will never fly with 3 gallons of fuel along with the battery power to last 11 hours. best of luck in your attempt.

mr_matt

My Feedback: (10)

A guy named Gary Mueller (http://www.angelfire.com/wi/jettech/) make tanks like this all of the time for jets. You usually shape a piece of foam to the size you need and send it to Gary and he makes the tanks from Kevlar or glass.

Your requirement is not a whole lot bigger than what a twin turbine carries, usually in 2 to 5 tanks with a fuel pumps.

You fuel pressure head is going to change a lot unless you keep the average pressure head nearly level (ie a big flat tank). Might need inflight mixture adjustment to compensate.

shawnkappner

My Feedback: (40)

Mr. Matt,

Thank you very much. I may just make one myself.

I am going to work with what I've got. What I plan on doing is fly a Curtiss Robin for as long as I can on July 21, 2005. That is 70 years after the Key Brothers set an endurance record of 653 hours of contiguous flight in a single engine Curtiss Robin airplane. My goal/plan is this... With a Curtiss Robin 99, A stone stock G-62 and a bunch of fuel, I'm going to see how long I can keep the plane aloft. My goal is a 1 hour to 1 minute ratio (653 minutes). I know I'm going to push the limits of the Curtiss Robin 99. As far as fuel consumption, I did some tests with a G-62 at 4000 RPM and a 24 X 6 Zinger prop . I would need 1.8 gallons at that RPM but realistically, I will need to turn a little more RPM than that and hence carry more fuel. The weight and wing loading compound issues quite a bit[sm=crying.gif]

I would like to build in the capacity to hold about 2.5 gallons of fuel which will add a little over 15 pounds of weight to the plane. I don't know If I could fill the tanks full or not. All planes are different as far as how much weight they can carry per square foot. That is something you have to sneak up on gradually.

Batteries are a non-issue. One 3000 milliamp pack would do it but I will have two on board for safety and backup. There will be VERY LITTLE servo movement and load so the battery drain will be minimal.

Again, this is just something fun and nothing more. I know there are more efficient ways to go about this but I'm just going to use what I have. If I make 653 minutes I will celebrate and have a few beers. If I don't, I will celebrate and have a few beers[sm=lol.gif]

Big_Bird

My Feedback: (1)

Shawn, you might get a bunch of the flat tanks like the jet guys use and place them between the wing ribs. Run enough fuel tubing so that only one end tank would have the vent.

Ken

Matt Kirsch

My Feedback: (21)

...and as far as the CG change goes, put the tanks on the CG. The engine has a pumped Walbro carb on it, so fuel tank location shouldn't matter.

shawnkappner

My Feedback: (40)

Yaaaaahooooooo!!!!


I tried at least 1/2 dozen stores and measured about a dozen different 1 gallon gas cans. I looked on the web for a custom made tank ($200 - No Thanks). I finally found a perfectly rectangular 1 gallon 4 oz can. Most cans have a slight taper making them too wide or are wider than my fuse. The deminsions of this tank couldn't get much better even if I had it custom made. It was an off brand that I hadn't seen in any other store I was previously in. The best part was the price ($1.99 each). So for $3.98 I'm getting 2 gallons and 8 oz of capacity in the main fuse then there is room for a 50 oz header tank in the engine box. If I wanted I could put two 50 oz tanks up front. All of the fuel will be centered over the CG. Having two 1 gallon tanks in the main fuse may be better than one 2 gallon tank since they will act as a baffle and prevent alot of weight shifting as the attitude of the plane shifts.

Thanks Guys!

Shawn

shawnkappner

My Feedback: (40)

Matt,

The CG will change a lot but hopefully not enough to make it totally unflyable. Imagine the three tanks lined up in a row. Two 1 gallon tanks in the fuse and the 50 OZ header that is in the engine conpartment right in front of the bulkhead and second 1 gallon tank. All three tanks are end to end (the only way they will fit). They span about 20 inches in length. As fuel is drawn, it will come out of the most aft tank 1st, then the middle, then the header tank. I will probably start out balanced or a little tail heavy then as the fuel is used it will go to a nose heavy condition, then back to balanced as the header tank is used up.

Mr Biplane

My Feedback: (6)

Try a Racing Kart shop, they have some very nice plastic tanks.

Dago Red

My Feedback: (11)

use coke bottles as tank, hang them from the wings. as you use them, drop them. jsut an idea.

Shortman

My Feedback: (21)

Baynard also had a mini alternator which you can buy from Sig. That way you can use a smaller battery and save more weight

Spaceclam

shawnkapper, i would do everything possible to lighten it up a bit. 3000 mah nicad packs will really weigh it down. that will weigh about 3 oz/cell. with a 4 cell receiver pack that puts you at 12 oz and two of those gives you 24 oz. NO WAY MAN. if 2200 mah is okay, www.batteriesamerica.com has some li-poly cells that weigh 1.6 oz. to make a receiver pack you ned another one to kick it up to 7.4 volts giving you 3 oz and a regulator to bring you down to 5 volts which is about an ounce so all up weight you will have about 4 oz as opposed to 24. 1.25 lbs saved right there. that's major. it will cost about $50 for the whole setup. if 2200 is not enough than you can paralell 2 smaller packs together than put them in series to get a receiver pack. either way you will be gaining valuable weight. also, try and put your fuel tanks right on your cg so as they empty it does not change anything. loosing 2.5 gallons of fuel in flight anywhere but on the cg will make a huge differencce, probably making it unflyable. while it would mean longer fuel lines and such you could put two the tanks in one of the gaps between the ribs in the wing and have it right on the cg and close to the plane as well. (look at the picture). even with the tanks there the cg will change a lot so keep it on the noseheavy side of their reccomendation. everything needs to be LIGHT or you will use more power which means less time. if you dont have to use as much power you can loose some fuel too. where is it flying to/from?