Moeller Gas Tank?

[sonex892]

Josh
You may have seen this setup before. Its not roto moulded plastic, but it takes up zero useable baggage space, holds 8 gals / 32 litres, weighs 6 lbs empty and can be removed or installed in 10 mins. I remove it before doing aerobatics.

PM me if you want details

Steve
Sonex 892

[jjbardell]

All great points. The 13 may be a bit overkill and I need to see how to secure a tank in well. I think there is a good compromise solution somewhere out there. Off to the web for Summit research.

[NWade]

An extra 5 gallons of fuel makes for a lot of options here in the west.

People keep talking about the weight of fuel and the weight of the tank. But you're not just adding a tank; you're adding a whole extra fuel system to the airplane! Sure, it doesn't go to the engine - it stops at the main tank - but its still a system with multiple components. I don't see many people discussing this. You need to include the weight of plumbing, fuel pump, vents, and fasteners. These all add weight. And are you going to bring any spares or repair items in case these break or develop a leak during a trip? As a rough planning number, I would add at least 5 lbs of system weight to Steve's (ingenious) "6 lb tank" - making it more like 11 lbs for the system.

While extra fuel is always nice, consider the useful load of the Sonex...

SCENARIO 1: You want to go a long way with a passenger on a single load of fuel
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If you're thinking of flying several hundred miles away from your home airport, you're probably going to be carrying two adults, plus some baggage, plus a normal Sonex load of fuel. That already puts you at or very near gross weight - even IF you specify a higher gross weight than Sonex Aircraft recommends. Let's do some Math:
650 lbs empty weight (somewhat optimistic considering the weight of most Sonexes)
360 lbs Humans
30 lbs baggage, tools, emergency kit, etc
90 lbs fuel
= 1130 lbs (which is already 30 lbs over factory gross)

How comfortable are you with flying at/above gross weight? Are you OK with only getting 400-500 fpm climbs? Have you considered things like density altitude and turbulence? Although I often fly at an airstrip on the west coast (at low altitude), I just spent a week in Idaho where the airport was at 5900' MSL and with the temp the DA was over 8000'. The takeoff run in my (non-Sonex) aircraft was double what I was used to!

You mentioned flying in the west, where many airstrips are narrow and relatively short, the air is rougher, and climb performance is important. Will your extra fuel-tank actually be useable in this scenario... Honestly? Is that 1 hr of extra flying time before a refuel worth all of the trade-offs? Will your passenger actually be OK flying for 3+ hours without a break? (And have both of you actually flown in a Sonex in order to know that answer for sure?)
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SCENARIO 2: You want to fly somewhere solo and not have to stop for fuel as often
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Compared to the first scenario, you've got an extra 100-200 lbs of load to work with. You also have free space on the seat.

For this scenario, at least a few Sonex pilots have used the "Turtle Buddy" from Turtle-Pac. Its fully removable, nearly doubles your useful range, and sits on the seat. Unlike the baggage compartment, the seat is designed to take this kind of weight and this fuel system will affect your CG in the same way that a passenger would.
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--Noel

[fastj22]

Scenerio #2 is where I'm at.
I talked to those dudes at AirVenture and the only problem is the price. Its well over $500 for their smallest system.
And you could accomplish the same effect with a marine dinghy fuel tank in the seat and a simple 12V pump.

[Bruce593SX]

The 13 gal is $1800+ ... Ug

[jjbardell]

I'm loving the discussion on this thread... :).

http://www2.cip1.com/ProductDetails.asp ... D201%2D100

This is 8" diameter and 30" long poly. The space in the between the seat is 33.5", so it will fit nicely behind there and being round, it only comes into the baggage compartment 4.5". The simple brackets for $10 will assist with mounting and easy removal. I can add a filler neck to the top of the seat for easy filling. The plumbing at the bottom will run nicely to the right side of the fuse and feed into the top plug of the main tank. A switch on my panel will activate the pump when the main gets to 8 gallons keeping CG balanced.

My Max Gross should not be an issue since we don't weigh much and it's only 6.5 gal. Based on other turbo burn rate threads, I estimate 22.5 total gallons @ 6.5gph and cruise of 140mph [I'd love to see 165+ at 10-12k...any reports of cruise above 10k?] gives me 3:15hrs time; 450nm cruise range and 30 min reserve. (Two stops to Sedona, AZ and non-stop to CLE...my requirements for my little birdie).

700 lbs empty weight (guessing I'll be 50lb heavy)
310 lbs People
30 lbs baggage, tools, emergency kit, etc
40 lbs fuel
= 1080 lbs

Feel free to challenge this. :)

[GordonTurner]

Plus....the main tank full weighs about 100lbs.

[DCASonex]

Josh
You may have seen this setup before. Its not roto moulded plastic, but it takes up zero useable baggage space, holds 8 gals / 32 litres, weighs 6 lbs empty and can be removed or installed in 10 mins. I remove it before doing aerobatics.

PM me if you want details

Steve
Sonex 892

Josh,

Looked at a lot of tank options when building mine and thought the one Steve mentions by far the best and made provisions for it. Ultimately found that long cross countries were most likely to include wife, and her tank capacity is less than the Sonex standard so never installed it but would give this a very good look if its eight gallons or so meets your needs.

Davud A.

[kmacht]

On my trip out to Oshkosh this year I found that 2.5 hours was the most I wanted to go with two people aboard before needing to get out and stretch. The sonex seat is nothing more than a hard metal pan and no matter how much foam you put down there things still get sore after a while. The most surprising problem was the back heels of my feet. I got a small blister on each one after the 10 hour flight from the floor vibrating while my feet were on the rudder pedals. You also can't stretch your legs or arms very easily in the plane with 2 people. Each stop that we made added less than 20 minutes to our time. We chose small airports with self serve fuel and could easily land, fuel the plane, hit the restroom, and be back in the air within 20 minutes. We also were surprised at how quickly the weight in our baggage compartment added up. The bruce's canopy cover was almost 10 pounds. The tiedows, two screwdrivers, a leatherman, a spare tire tube, and some rags added another 12. That is over 20+ pounds of baggage before adding the weight of another fuel tank never mind the fuel itself. Think about the type of flying you are going to really do and compare that to the type of flying you have done so far. Do you really plan on doing many 4+ hour legs without a 20 minute fuel stop that it justifies the extra cost, weight, and complexity of a secondary fuel tank? This is experimental aviation so everyone is free to do what they want with their plane. I'm just cautioning against adding unnecessary time and complexity to the build when you could instead be that much closer to flying.

Keith
#554

[jjbardell]

I will look into Steve's tank for sure before I make a final decision. It looks great.
I have been renting an Archer for years now and we often fly to CLE from west of ORD. The distance is 310nm and we currently do it in 3:05h. I feel confident the Sonex can do it in 2.5h at a fraction of the cost if we can get 6-8 more gallons in.

My main reason for building a Sonex was the cost of xcntry flying. The Archer is just under $1,000RT to CLE. I chose not to spend that anymore. My family lives in Sedona AZ (1,050nm). I would like to start seeing them quarterly. So, I searched for a plane that was small, fast and inexpensive to fly. There is no other on the market. An RV-7 would be great if I had the extra cash to maintain and operate the IO engine. A Pulsar Turbo was looking good but they are an expensive overhaul with that Rotax 912IS for the speed you get. A Sonex with the right panel and turbo can get me there safely in a reasonable time (#praying for 160mph @ 10.5k-12.5k cruise), planning a 140mph cruise.

So for me, this plane is really designed as a VW GTI (my car) for skies. Economical, practical, a little small, a little sporty...a great xcntry machine if you don't mind a smaller firmer ride.

I agree with all of the above comments from everyone. It's a trade-off and I am probably using the Sonex for more than it's original intention. I would be happy with the original setup if I knew it would get me 350nm.