• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

To Belly bod or not to Belly pod, that is the question

Fortysix12

Registered User
RanchAero Grand Vista, Brooksville
Building an 18A with standard 18 a side. Do I put one in with or with out fuel. Comments anyone.
 
Mike,

What is the intended purpose of the airplane? For most of the stuff I want to do, 36 gallons in a Cub isn't enough, but if you're landing in rock piles ten miles from home, it's fine.

What's the mission?

MTV
 
When I got 83Z, it had a belly pod., and I planned to take it off. It is still there. Mike is correct about the missions, but I use mine for a lot of gas on a short ride. 31 gal on 100 LL in the belly from Port Alsworth can quickly give me a supply at home that would come in 5 gal cans otherwise.

I also check and sump the belly, run the pump to make sure it works, keep a spare flexible container, and always have that spare 5 gal in the belly.

GR
 
I've always been a mission evaluation guy, but I think what I wanted was to hear different perspectives on the use, utility and overall experiences. 160 HP and 38 gallons doesn't allow for much flexibility. So I vote for my self to get one with fuel. But I've never an 18 with one but could always use the more space on longer trips in the 12. I'm building the 18 hoping to cover all the bases. Seems like the 23 extra gallons is a good thing. One point someone had made is that you lug it everywhere you go once you get to your destination, where with the pigs you take them out at camp. seems like I would transfer the fuel back into the mains and continue on with the flying.
 
A knowledgeable cub friend ask me why I even put fuel in the right tank. He said you don't need it when your mostly flying near the grass field. I told him that I always thought it was good to balance out the cub........he just laughed and said, why carry around the extra weight, especially when landing on rough places. I had to agree, but also, I will say, that after reading a post about letting one tank go dry, and drying out the gaskets dose'nt make sence either. I keep 5 gallans in the right tank all the time when just messing around. I burn it up every other fill up so it stays clean and fresh. I like both tanks filled and I would like to have a belly tank but can tell a big difference in my cubs performance when my wife's out of the back seat and I only carry half fuel. I could also lose 50 pounds and my cub would thank me. Who has the magic pill for that? Mark
 
It all depends on the mission. Up North, there is no such thing as too much fuel. I spent all summer hauling gas around for a fellow cuber that had standard tanks. Granted my cub preforms much differently loaded with 68 gallons of gas, versus 36 or even 18, but having the option to load up with gas or not -- is priceless.

Gas is your friend, except when you are on fire!!!!
 
Fortysix12,

I have had a straight "Firman Pod" for around 10 years or so and when I build another cub it will be transferred to the new cub because I can't live without my pod. I have had a 10X10 bombshelter tent, two folding chairs, two walking sticks, small sledge, a bunch of duckbills & drive rod, two five gallon gas cans, a gallon of coleman fuel, a small tarp, hiking boots and assorted other junk, otherwise a luxury camp in the pod all at one time. The full size pod can easily hold 24 gallons of gas in 6 gallon cans and still have room for some gear. I know of a friend that has stuffed 40 gallons of gas in his pod but has some very unique cans.

The things that I like about my straight pod is the flexibility to haul fuel, gear, meat, or any other stuff I feel like without having a portion dedicated to fuel that is only needed on long trips. You can also shed all the gear in your pod without the difficulty of fuel transfer. Just toss the stuff in the woods and go.

There is some loss of flexibility in straight pods because of the difficulty of transferring fuel any place other than firmly planted on the ground. Other than that, if you are ok with pulling out five or six gallon cans and stepping up on the wheels and fueling via a can named after none other than me, consider the straight pod as an option.

Other benefits to the straight pod include the ability to hold longer material, via the rear door (on newer pods), like ski's, lumber, or anything that is short of the full length of the pod.

As for this mission stuff, I think that whatever decision you make, I seriously doubt you will be dissatisfied with the pod you choose. Also keep in mind that missions change over time and either pod will accomplish an array of missions that require more fuel or gear.

Good Luck - Jerry

68766716.vY5qGB4u.podfueling.jpg
 
fortysix12,

I would put Atlee's long range tanks in, 30.5 gals. a side, this also gets rid of your header tanks. :D Put Cub Crafters fuel selector in elimanating another problem and run selector on both. :D You don't have to fill them up, but you now have range when needed. You won't have to worry about transferring fuel, or if it will transfer when needed. :eek: If your rebuilding, add extended baggage inside. Good Luck!
 
I have the landes cargo only pod. I can carry 4 5 gallon fuel bladders in the pod. I can quickly drop these off and be on my way. When empty, they lay flat and take up hardly any room. I seem to need more room for stuff than fuel. The landes pod does have a smaller door, but it always seems to work out.
 
No question, in my opinion, the combo belly tank/pod answers this problem.

Landes' combo pod gives an extra 18 gals, (50% more fuel for those of us with 18 gal tanks), & still offers room for extra stuff.

I find, especially on floats, that to find an adequate place to stop and add gas from cans becomes a hassle, esp. when short on suitable lakes as well as time.

While a full belly tank is very nice to have, just once again this fall witnessed that it IS POSSIBLE (aghast!) to OVERLOAD a cub with full tanks, full belly tank, & inside stuffed with people & gear.
I find that if I'm taking as much fuel as possible, it's not the only thing I am carrying on a long trip.... (Standard hunting / fishing adventure across Alaska)

Hands down, fuel on demand and a little extra room is a great option. I just wish there was a lot more of these out there & for sale used making them more affordable!!!

http://www.airglas.com/gas_cargo_pod/index.html

Kevin
 
Someone suggested getting rid of header tanks and putting a both position of the fuel selector valve. I strongly disagree.

Two major reasons are porting of the tanks duing wing low operations including takoffs from slanted beachs, hight angel of attack climbs and steep turns. In an 18 it is required to take off and land on the left tank only. Some earlier manuals failed to say this but the later ones do. IT IS CRITICAL TO TAKE OFF ON THE LEFT TANK. The right header tank can be too low to feed the engine during a high angle climb. If the right wing is low on takeoff as would be the case on a slanted beach with right wing low, it can port in a low fuel condition. Most of the cubs are now built with left tank forward feeds. The 12's were not. If the left wing is low on fuel and low on the beach, at least the header tank will feed the engine during that time. There is also a difficulty in draining all the water that may be in a tank. If we have missed small amounts of water often it will be ingested and pass through the engine. If there is large amounts of water it is a different story.

While a right / left switch requires more management it is much safer. With a low dihedral angle wing such as the cubs or 12s have, if the aircraft is on a slight slant (one axel 6/10ths of an inch higher than the other) water will flow to the lowest spot in the tank whcih will be on the outboard side of the low wing. that means when you drain fuel to check for water in the low wing, you will get water that is in the sump of the low wing only, the rest of the water is in the outboard end of the low wing. Note that the original 12 tanks have no sumps, they have quick drains only wich are forward of the aft end and usually oil canned up and water sits in around the raised quick drain.

If one steps on the brake while turning into a tie down and streaches out one bunji, or ties one wing down firmly prior to the other, (more often than not, the right wing) it pulls down one wing and water will flow to the low end (outboard end) of the tank. If there is more water than will be collected in the sump, and there can be, it will be in the low outboard end of the tank.

If one is standing on the left float when he checks fuel for water his wieght pushes that float down in the water and he will fail to get all the water that is in the tank (it is in the outboard end). To check the left tank walk out on the right float, lean through the aircraft and check the left tank keeping the weight on the right side of the aircraft. Take off on the left tank and switch to the right tank when you are high enough and in a position where a shot of water will not put you on the ground or in the water. With some inginuity such as a long piece of pvc pipe, one can check the right wing without standing on the right float.

On a 12 unless the single piece rear window has been chgned in some fasion so you can reach the left tank from the right side of the aircraft, or otherwise developed a way to check fuel without standing on the left float, IT IS UNSAFE TO FLY. The 12 should be converted to a left / right valve so that you can take off on the left tank only. THE ORIGINAL 12 TANKS ARE ALWAYS UNSAFE.

In an 18 it is required to take off and land on the left tank only. Some earlier manuals failed to say this but the later ones do. IT IS CRITICAL TO TAKE OFF ON THE LEFT TANK. The right header tank can be too low to feed the engine during a high angle climb. If the right wing is low on takeoff as would be the case on a slanted beach with right wing low, it can port in a low fuel condition.

I checked a five year peiod of NTSB records and found that the general aviation accident rate as the result of engine failure due to water in the fuel was 1.8/100,00 hrs, Pa 18 was 2.5/100,000 hrs (low dihedreal wing angle) and the Pa 11,s Pa 16s, were lumped in with the 12,s and probably squewed the 12 numbers low but it was 5.19/100,000 hours. I also set several tanks with tops cut out on the bench at various angles of incidence at the proper dihedral angle. Water flows to the outboard side if the wing is low.

CHANGE 12 TANKS there are several options AND PUT SUMPS ON THE TANKS if they don't have any. THE 18 TANKS HAVE SUMPS ON THE INBOARD AND OUTBOARD SIDES OF THE BOTTOM STAMPING. PUT A QUICK DRAIN FITTING IN THE OUTBOARD SIDE SO YOU CAN DRAIN BOTH THE INBOARD AND OUTBOARD SIDE OF EACH TANK AT ANY ANGLE.

As far as the header tank is concerned, they are necessary unless you have a forward feed from the left tank.

If there are more questions about the original Pa 12 tanks I can make a suggestion of two.
 
reliableflyer said:
If one is standing on the left float when he checks fuel for water his wieght pushes that float down in the water and he will fail to get all the water that is in the tank (it is in the outboard end). To check the left tank walk out on the right float, lean through the aircraft and check the left tank keeping the weight on the right side of the aircraft. Take off on the left tank and switch to the right tank when you are high enough and in a position where a shot of water will not put you on the ground or in the water. With some inginuity such as a long piece of pvc pipe, one can check the right wing without standing on the right float.
.

That is some great advice.

I will have to look into putting the extra outboard sump in my J-5 rebuild with the Air Energy Tanks.

Tim
 
Tim,

Better yet, add your own low-point sumps. This is a pic of the left lower longeron on my 12 at the early stages.
pa_12_11-10-03_010.jpg


Stewart
 
reliableflyer

Atlee Dodge Tanks feed from the front and the back on both tanks!
Fuel selector on both provides fuel from both tanks ALWAYS.
It don't matter if I'm taking off, landing, or knife edge I've got a gas supply ALWAYS, unless I'm bone dry. If I have water it's in my gasgalator
although I do check my tanks also. Explain to me how you drain the water and gunk from those header tanks? If someone is rebuilding, header tanks are the first thing I'd get rid of. Atlee's Tanks and a fuel selector you can run on both with no AD, are VERY SAFE and RELIABLE. Sometimes when things are simple, nobody wants to believe it.
 
In addition to having an inboard and outboard quick drain on each wing tank I have an extra quick drain on my aft header tank similiar to the one that StewartB has shown a picture of.

When they built these things they missed stuff. We need to look at the big picture, not just what was original, add a drain in every spot that will be low during our operations.

Also note that a quick drain is not a sump. A sump is a depression in the bottom of a tank which collects water. The quick drain simply lets us drain what has collected. If a tank has no sump then the water moves to the lowest spot depending on the planes position at that time. That spot changes depending on the position of the plane. Tanks that don't have sumps are a problem and they should be added. I used a piece of tubing capped at the end and located at the lowest spot with a fitting and a quick drain in it. The 12 has no sump and as we push up on the spring of the quick drain over the years it oil cans up and the water sit around it.
 
widebody is correct, if you have a forward feed from both tanks as well as aft feeds you always have a fuel flow regardless of angle. In this configuration as far as I know, you can dispense with header tanks.
 
While most of the J-5 and Pa-12 are the same I am not sure about the tanks but I assume they are the same as well. Behindpropellers, if your tanks are the same as the 12, they are made of turnplate which is very brittle and cracks easily. Many have been sloshed. They have three rib stiffiners in the bottom (and top) of the 19 gal tank. These stiffiners hold water forward of the ribs and the quick drain. While there is a provision for water to get it is not adequate and is restricted even more if the tank sides have any dents or the tanks have been sloshed.

There is alo no sump in the tanks and the quick drain is located three and a half inches forward of the aft end. There are replacement tanks, available. Throw yours away and get some replacement tanks. I think either Dakota cub or lee Boodie has one, Atlee's tank's, Clarence Whitt (the cub club can steer you to him) and Wag aero which makes a non pma replacment). If there is no sump an any of them, weld a piece of tubing with the end capped and a quick drain in the bottom. If the tank is the same shape as the original 12 tank, weld the sump all the way aft on the tank. On the original aircraft water can lay aft of the quick drain and is exacerbated by big tiers or long gear legs.

The original tanks tend to crack although even the cub aluminum tanks will crack. We put funnels and rest a five gallon can or a six hundred horse power fuel filler nozel on the neck and many are cracked. We then put a rubber gasket around the filler neck to keep overfills from running down into the wing and then water sits around the neck (and the cracks that develop there) and leak into the tank.

Some people think they never get water from condensation but it happens and usually it is small amounts that pass through during flight. If the aircraft sits a long time, your gambeling if you don't do a good fuel drain.
 
reliableflyer said:
While most of the J-5 and Pa-12 are the same I am not sure about the tanks but I assume they are the same as well. Behindpropellers, if your tanks are the same as the 12, they are made of turnplate which is very brittle and cracks easily. Many have been sloshed. They have three rib stiffiners in the bottom (and top) of the 19 gal tank. These stiffiners hold water forward of the ribs and the quick drain. While there is a provision for water to get it is not adequate and is restricted even more if the tank sides have any dents or the tanks have been sloshed.

These are new tanks, Clarence Witte tanks actually. They have provisions for fwd and rear fuel outlets on both tanks as well as a drain or sump in the rear of the tank. I plan on using the Cessna style system along with the left/right/both/off fuel valve. Right now I am trying to get Cubcrafters to write me a deviation for their headerless STC to make less the paperwork for both me and my IA. It will get a Steve's gascolator on the firewall.
Tim
 
I don't know how to quote yet. So.

reliableflyer said- "when they built these things they missed stuff."

Yeh you got to wonder. But I guess it was 60+ years ago.

behindpropellers said-"It will get a Steve's Gascolater on the firewall."

Definitly. For those of you still running Pipers, perform this test and then buy one also. Take your thumb, apply slight presure to Pipers Gascolater, won't take much and gas sprays everywhere. If things go bad and you make it through the crash, I'll bet your on fire. Get a good Gascolater!!
 
Question for you belly pod folks.

Does the STC for the belly pod installation prohibit intensional spins????


xx
 
Back
Top