How to Build a Fuel Truck

kyleb said:
I was going to post something similar. The 235 hp engine had 7.2:1 compression. The 180 hp engines have 8.5:1. Given that he lives in a very hot climate and at sea level, he's in the worst possible situation for damaging his engine using low octane fuel. If I was Jay, I'd religiously mix in at least 25% 100 LL to help with the octane issue. TEL is a tremendous octane booster and at that concentration might provide enough octane to keep his engine happy over the long term. (Also, it might not.)

RVP is another issue. I'd check it regularly to preclude vapor lock. Again, Jay is more at risk for vapor lock than many others because of the hot climate and his dark colored fuel tanks, which (compared to white tanks) will absorb more heat on a sunny ramp. Vapor lock is most likely following a quick turn-around on a hot day.

Saving $2/gallon is great when there is no downside. There are downsides in Jay's situation.
Click to expand...
Given how we fly, odds are we will never approach 100% mogas.

Actually, with all the short flights lately (due to crappy weather) we are probably getting close to 75% mogas right now. Our low compression O- (not IO-) 360 is running wonderfully on it.

When I was looking for an RV-8 I specifically eliminated the high compression 200 HP IO-360s knowing that the day was rapidly approaching when 100LL was going away. Mogas works great in carbureted low compression Lycosaurs.

Again, I didn't do this to save money, although it's a nice side effect. I did it to quit fouling everything in my engine with lead build up. Fouled plugs and crudded up (that's a technical term) pistons have convinced me that it's time to stop burning 100LL as much as possible. YMMV.
 
txflyer said:
Just a word of caution.

I had a friend who got rear ended by a truck while he was pulling a gooseneck with a tool-and-tank with gasoline in it. The gooseneck broke loose and rammed into the tank and it was bye-bye friend. This is why I like diesel so much for transport. But that's another subject.

Point is, I wouldn't use my gas (fuel) truck as a family hauler ... especially pulling a gooseneck unless the buddy tank were empty and vented. :redface:
Click to expand...
Yeah, I'm sure getting t-boned with 100 gallons of gas in back would make a nice explosion. Then again, I could fall in the shower.
 
Jay Honeck said:
Given how we fly, odds are we will never approach 100% mogas.

Actually, with all the short flights lately (due to crappy weather) we are probably getting close to 75% mogas right now. Our low compression O- (not IO-) 360 is running wonderfully on it.
Click to expand...

Your Pathfinder had 7.2:1 compression. Your RV has 8.5:1. It is not a low compression engine. I suspect the dataplate on it mandates 90+ octane. There is a valid engineering reason for that - the marketing department would have loved it if it could have run on bilge water. The 200 hp engines are either 8.7 or 9.0:1 compression, IIRC. Do a Google search for the TCDS for your engine to confirm what I'm relating here...

Also, remember that octane is measured differently in automotive applications than aviation applications. The differences mean your 87 octane fuel would likely register lower using the standard tests used in aviation.

A friend's O-320 in his RV was routinely run on 87 octane fuel. That engine suffered broken piston skirts in the wrist pin area on two cylinders. No telling if there is a connection between the fuel and the piston problems, but...

Oh, and sorry for 'jacking your thread. The subject is very worthwhile, and I've been tempted several times to work out a fuel trailer for my own use (never have - too many irons in the fire already).
 
Last edited:
kyleb said:
Also, remember that octane is measured differently in automotive applications than aviation applications. The differences mean your 87 octane fuel would likely register lower using the standard tests used in aviation.
Click to expand...

80 octane aviation fuel was almost the exact same formula as the old regular, leaded auto gas. As you say, it's just measured on a different scale.
 
kyleb said:
Your Pathfinder had 7.2:1 compression. Your RV has 8.5:1. It is not a low compression engine. I suspect the dataplate on it mandates 90+ octane. There is a valid engineering reason for that - the marketing department would have loved it if it could have run on bilge water. The 200 hp engines are either 8.7 or 9.0:1 compression, IIRC. Do a Google search for the TCDS for your engine to confirm what I'm relating here...

Also, remember that octane is measured differently in automotive applications than aviation applications. The differences mean your 87 octane fuel would likely register lower using the standard tests used in aviation.

A friends' O-320 in his RV was routinely run on 87 octane fuel. That engine suffered broken piston skirts in the wrist pin area on two cylinders. No telling if there is a connection between the fuel and the piston problems, but...

Oh, and sorry for 'jacking your thread. The subject is very worthwhile, and I've been tempted several times to work out a fuel trailer for my own use (never have - too many irons in the fire already).
Click to expand...
you can find anecdotes to support any conclusion. fact is, many, many 180hp O-360's and 250hp O-540's in experimentals are burning mogas and it just hasn't been a big issue. There's plenty of discussion on vans, backcountry, etc forums if you're interested. Is it 100% proper per the engine manufacturer's intention, no it's not. But they seem to get away with it.
 
Stewartb said:
no placards are required and DOT rules don't apply as long as the tank capacity is 119 gallons or less.
Click to expand...
It may not be required, but putting an ERRONEOUS placard is probably not a good idea.
 
Jay if you have any concerns with water in the fuel ( and it is a fact that all gas staions have some water in thier tanks ). There is a spin on filter taht will fit your rig and is for ethanol gas. While it says ethanol on it what it does is detect and react to water. If any water gets into it then it will close oof the flow of fuel to a tricle indicating it needs to be changed due to water. They come in 5 and 10 micron ratings. I am sure you check your fuel loads for ethanol but if not I would reccomend it since more than one tank has had the wrong fuel loaded into it and they just pump it on through. Another poster suggested that the grounding reel be attached to the tank and I would agree due to the fact that many of the farm hoses ( what usually comes with the pump ). Do not have a static wire in the hose. You stated yours does which is fine.
 
JHW said:
you can find anecdotes to support any conclusion. fact is, many, many 180hp O-360's and 250hp O-540's in experimentals are burning mogas and it just hasn't been a big issue. There's plenty of discussion on vans, backcountry, etc forums if you're interested. Is it 100% proper per the engine manufacturer's intention, no it's not. But they seem to get away with it.
Click to expand...

The question is "What mogas (87 octane, 91, or 93?), and in engines with what compression?" This isn't a one size fits all answer here.

As far as people "getting away with it", there were several ex-mogas users who posted in a discussion on VAF recently. In-flight vapor lock was their primary reason for moving back to Avgas.

As you say, there are plenty of anecdotes. Personally, I wouldn't run a slow turning, large combustion chamber, 8.5:1 compression engine on 87 R+M/2 octane fuel. At takeoff on a hot day at sea level, bad things could happen. At high altitude cruise? Probably not an issue.
 
kyleb said:
At high altitude cruise? Probably not an issue.
Click to expand...

No "probably" to it, do the math. At 5,000' there is not problem. At sea level, I don't know that there will be a problem but that is the only place it will happen. I suspect that just setting up the carb on the rich side at WOT will protect the engine but a little testing would figure that out real quick. If the engine has an engine monitor then the operator will know very quickly if there is a problem with the gas.
 
Clark1961 said:
No "probably" to it, do the math. At 5,000' there is not problem. At sea level, I don't know that there will be a problem but that is the only place it will happen. I suspect that just setting up the carb on the rich side at WOT will protect the engine but a little testing would figure that out real quick. If the engine has an engine monitor then the operator will know very quickly if there is a problem with the gas.
Click to expand...
We will never be running on pure mogas. It's simply not possible to obtain everywhere we go.

The mix of 100LL and 87 mogas should be....perfect. :)
 
Jay Honeck said:
Thanks, guys. A few notes in reply:
Re: Grounding. The hose has a metal grounding mesh embedded in the rubber. This means every time you pump gas, the plane and truck are grounded, which is why I am 99% certain that the retractable grounding wire is unneeded. Still, belt and suspenders.
Click to expand...
I thought the issue was that you do not want a spark at the filler neck caused by static buildup during filling. That's why you want a constant connection between the tank and plane away from where you're filling.
 
Lindberg said:
I thought the issue was that you do not want a spark at the filler neck caused by static buildup during filling. That's why you want a constant connection between the tank and plane away from where you're filling.
Click to expand...

All gasoline fuel pumps I have bought over the last 20 years came with a hose that had a grounding wire imbedded in it..... Just touch the plane somewhere before fueling, insert the nozzle with a decent metal to metal contact......

Easy Pleasy..... IMHO..
 
There are a few low compression O-360s that are rated at 168 HP.

Minimum fuel grade 80/87 avgas, compression ratio 7.20:1.

(O-360-B1A, B1B, B2A, B2B, B2C, D1A, D2A, D2B.)

Everything else requires higher.
(Minimum fuel grade 91/96 avgas, compression ratio 8.50:1.
Minimum fuel grade 100 or 100LL avgas, compression ratio 9.00:1.
etc...)

25% 100LL and 75% 87 octane pump gas (call it 80 octane aviation equivalent) would give you 95 octane fuel with just the right amount of lead.

http://en.wikipedia.org/wiki/List_of_Lycoming_O-360_variants
 
kyleb said:
The question is "What mogas (87 octane, 91, or 93?), and in engines with what compression?" This isn't a one size fits all answer here.

As far as people "getting away with it", there were several ex-mogas users who posted in a discussion on VAF recently. In-flight vapor lock was their primary reason for moving back to Avgas.

As you say, there are plenty of anecdotes. Personally, I wouldn't run a slow turning, large combustion chamber, 8.5:1 compression engine on 87 R+M/2 octane fuel. At takeoff on a hot day at sea level, bad things could happen. At high altitude cruise? Probably not an issue.
Click to expand...
that's why a lot of people run blue gas in one tank and smelly gas in the others
 
Jay Honeck said:
As a side note, I have not found a source for unpolluted premium mogas here in Texas. The place I get it handles only regular.

Which will work fine.
Click to expand...
it's the opposite in IL, you can usually only find 91-93
 
Lindberg said:
I thought the issue was that you do not want a spark at the filler neck caused by static buildup during filling. That's why you want a constant connection between the tank and plane away from where you're filling.
Click to expand...

Any time a fluid flows through a non-conductive connection, to include falling from the nozzle to the tank you have the potential for static build up. Yes since the hose is conductive and you've got the thing in contact with the tank lip, you should have less of an issue, but it's not all that great of a connection. Belt and suspenders is right. I won't omit it.

Back when I was in the fire service, we got some pretty good training on static buildup and fuel transfers. I've not seen any fueling accidents but I've had two friend's whose planes were destroyed on DEFUELING accidents. The practice of just wheeling the drum under the wing and opening (or removing) the quick drain is VERY DANGEROUS.

One day I was at a nearby airport and the guy was refiling the fuel truck from the big tank on the field. He was standing on top of the thing, fuel flowing in free air, no ground, and there was a thunderstorm coming through the area. About the only thing he could have done to increase the risk was to be smoking at the time.
 
timwinters said:
Same here in MO. And it's still almost $2/gal cheaper than 100LL. I typically run a 75/25 blend.
Click to expand...
there was one time i can think of that our local station ran out of 91 no-alcohol. I had promised the kids we'd go tubing and there is no way I'm putting alcohol in the fiberglass tank. So I topped the boat with 100LL. It was empty. As I watched the avgas gallons count up, it occurred to me that i could have siphoned the mogas from the farmall for part of it. I didn't calculate the hourly cost of tubing that day and even now I'm trying to think of other things so i don't cipher it in my head.
 
N801BH said:
All gasoline fuel pumps I have bought over the last 20 years came with a hose that had a grounding wire imbedded in it..... Just touch the plane somewhere before fueling, insert the nozzle with a decent metal to metal contact......

Easy Pleasy..... IMHO..
Click to expand...

This works for cars where the nozzle mates with the filler neck. I can't claim to have seen all that many planes, but none of the ones of flown have a filler neck that's designed to have the nozzle rested in contact with it.
 
Lindberg said:
This works for cars where the nozzle mates with the filler neck. I can't claim to have seen all that many planes, but none of the ones of flown have a filler neck that's designed to have the nozzle rested in contact with it.
Click to expand...

:confused:

:dunno:
 
On grounding,
Pumping from a truck requires that a bonding wire be attached anytime flammable liquids are discharged into a top fill tank. Trucks are insulated from ground by rubber tires, so when a bonding wire is attached to the tank being filled, a continuous path to ground is provided. But the length of time required for static electricity to dissipate varies. If the bonding wire is removed before static electricity is dissipated, a spark is likely to occur. Therefore, grounding the truck in addition to bonding to the tank being filled addresses this issue and is required by OSHA regulation. Grounding trucks during fuel dispensing is prescribed in National Fire Protection Association (NFPA) guidelines as well. Allowing a few minutes before removing nozzles when the pumping is complete also helps assure that static electricity has dissipated.

Also this from NFPA:
5.4.6​
​
​
​
​
Conductive hose shall be used to prevent electrostatic discharge but shall not be used to accomplish required bonding.​

 
Mobile fuel trucks that service Lake Hood airplanes don't ground like we see airline fuelers do. They do bond. I have a seperate bonding wire for my truck tank but rarely use it. My hose conductivity has proven to be good. I do keep thenozzle in contact with the filler neck. The notion that a momentary touch of nozzle to airframe is adequate is incorrect. Static potential between tank and airframe are one thing but static generation during fuel dispensing is always a threat, as is static made by your movements while holding the nozzle.
 
I'm trying to think of a way to fuel WITHOUT touching the nozzle to the filler neck. In my plane, anyway, it would be a delicate exercise, like playing "Operation" when we were kids. ;-)

We connect the static line religiously, despite all evidence that it is unnecessary. There's just no sense in risking a spark.
 
So for those of us that have easy access to pure gas, why not just use the installed gas tank in your car/truck? I just need to figure out where to tap in a T in the line, and put in a quick connect with a cap to keep it clean. From there you just use an inexpensive facet fuel pump or find a way to trick the cars pump into running whenever you want it to, and then run a line from the car to the plane. And ground everything. And don't pump the car dry or you won't be having fun.
 
Kiddo's Driver said:
So for those of us that have easy access to pure gas, why not just use the installed gas tank in your car/truck? I just need to figure out where to tap in a T in the line, and put in a quick connect with a cap to keep it clean. From there you just use an inexpensive facet fuel pump or find a way to trick the cars pump into running whenever you want it to, and then run a line from the car to the plane. And ground everything. And don't pump the car dry or you won't be having fun.
Click to expand...
That seems very complicated compared to a fuel transfer tank installation. But if you found an easy way to do it, you could market a kit for it...

...for only $19.95. Plus $250 to cover your liability insurance.

;-)
 
Kiddo's Driver said:
So for those of us that have easy access to pure gas, why not just use the installed gas tank in your car/truck? I just need to figure out where to tap in a T in the line, and put in a quick connect with a cap to keep it clean. From there you just use an inexpensive facet fuel pump or find a way to trick the cars pump into running whenever you want it to, and then run a line from the car to the plane. And ground everything. And don't pump the car dry or you won't be having fun.
Click to expand...
Too little capacity, too low a fill rate
 
You must log in or register to reply here.
Back
Top