Waiex-B 0022

[WaiexB22]

For the panel...I have been putting of cutting holes here for a while. I think the time is going to have to come soon to stat putting things in. Here is my current plan. The throttle and trim are not shown, but the will be on the bottom left (setup for flying English).

Does anyone have experience with the AV-30 vs. a Garmin G5? I can't decide which I prefer.

I have removed the fuel tank to install the components on the firewall. It needed to come out for the service bulletin on the straps on the b model anyways, so no real biggie. It will give me a chance to add a fitting to the top of the tank for an auxiliary tank, since I am planning to install one behind my seat. I have the fuel pump components as well. I am running 2 fuel pumps in parallel for redundancy. I am also running dual filters with one on the discharge of each pump. There are check valves built into the pumps and plenty of people flying this engine rely on that check valve to maintain pressure in the system. Personally, I think that is a bad idea, so I am running an external check valve on the discharge of each filter. A rough sketch of my fuel system diagram is below. The fuel pump setup is a little heavy (about 5-6 pounds total), but I think it will be robust and reliable. Considering fuel supply and delivery accounts for most engine failures I want to make sure I always have a good stable supply of fuel. I have been holding off assembling the fuel pumps until I'm not doing so much dusty fab work, I don't want to get garbage in my pumps.

Hangar space in my area is limited to say the least. I lucked into a hangar because the guys ahead of me couldn't fit and I got wind of the opening through my local EAA chapter. I went ahead and secured the spot in a shared hangar at 14A in Mooresville, NC about 20 minutes form home.

[sonex892.]

Cant help with the avionics.
Your fuel system is similar to mine with a 32 litre tank behind the seat. I mostly leave the aux tank out of the aircraft.

Instead of transferring fuel I manage the fuel with a 3 way selector valve mounted to the firewall, the actuator shaft is extended to under the instrument panel. OFF / MAIN /AUX.

I chose not to transfer from aux to main, my thoughts were it eliminates any chance of pumping fuel overboard. It also helps with trimming, I generally take off on the main then go to the aux and alternate supply every 30 mins. The aux pump is never required it is purely a backup should the Jabiru engine driven pump fail.

[WaiexB22]

Thanks for the suggestion! Generally, I like the simplicity and flexibility of your system. The biggest problem with direct feed from the aux tank in my situation is the lack of elevation to create suction head at the pumps. The aux tank will sit down low in the back and the fuel pumps are on the firewall at or above the outlet of the aux tank. I plan to make the aux tank permanent.

The other reason I am using an aux tank is that I hope to fill through a fill port on aft side and then transfer fuel to my main tank. I hope to significantly reduce the number of times I refuel around the windshield that is prone to crack when fuel gets spilled on it. I am planning on using a BIG transfer pump with big AN lines to move the fuel as fast as possible. The idea being that I can transfer on the ground during taxi if needed for W&B. With the prop I'm running I don't think it will be a problem, but time will tell. I will be running ethanol free mogas that I carry to the airport in a tank in my truck. 95% of my flying is within an hour of home and for fun, so I think my typical fuel burn should be around the capacity of my aux tank. Then when I do fly a cross county, I get more range to search for mogas.

Having said all that, I considered using the aux like a header tank in a high wing, where I fed the main tank through a small aux tank in the rear, then feed the fuel pumps from the smaller tank and place them in the back. I wouldn't need a transfer pump it this case, but I would have to fill through the windshield all the time. Also, I don't really want high pressure fuel lines in the cockpit that have to run to keep the engine running. A transfer line is different IMO because it can be shutoff with no adverse affects on the engine running. Lastly, the W&B might be a problem with no fuel in the main tank and the "aux" tank in the rear full.

[flyguy0609]

It would be really nice to have just another hour of fuel. Like 8 gallons. So I looked at it. THe Sonex meets the +6 G aerobatic requirement at 950 pounds. That is the equivalent of 5,700 lbs. Divide that by 1,320 and you get 4.318 G's That is just under the utility category 4.4 g requirement. Structurally OK. I was thinking about an auxillary tank 8 gallons. I ruled out tube tanks in the wings for a couple of reason. First the ratio of structural weight to fuel weight is not good. Second (and more importantly) is that in the case of a spin, the fuel in those tanks will flow to the wing tips, making recovery problematic. The Yankee AA-1 was spin restricted because the tubular wing spars which serve as fuel tanks. That is not a part of the flight envelope I wish to explore. Next best spot is behind the pilots seat. I then read a post (some where on this forum) about a long XC flight with the new pilot, an instructor, baggage and aux fuel behind the pilot seat, which require nearly full forward stick to maintain level flight which concerned me. I decided to model the resulting cg. With 350 lbs pilot & pass, 40 lbs baggage, 102 lbs main fuel, and 48 lbs aux fuel. For modeling the cg, I used a moment arm for the aux fuel that was at the midpoint between the Pilot/Passenger seat and the baggage moment arm. With 48 lbs aux fuel at take off the cg was at 95% of the full aft position. As the fuel burns off the cg moves further aft. When the main tanks are half full, the cg has moved to 99% of the full aft position. Personally, I'd rather make an extra fuel stop. I think it would be a good idea to get out your cg calculator, add an extra line for aux fuel, plot a number of scenarios.

[WaiexB22]

Thanks for the comments on the W&B! I do have concerns under certain circumstances especially considering my engine and FWF weight is only a few pounds heavier than a rotax. I also have concerns for W&B in the event of a transfer pump failure if I take off with full fuel. Generally speaking I do not intend to run around my local area with 28 gallons of fuel on board. This is something I will need to explore fully once I have the plane fully built and I have some actual weights to work with. I have it ready to go on the gear, I just have been procrastinating because they are a tripping hazard in my little shop while I work on engine stuff. I also can't rig my wings up in my shop. All I have right now are other peoples numbers.

Does anybody have any weight and balance with the wings off and/or know what the wings weigh and where their CG is?

I am doing a few things that I hope will mitigate the weight in the back since it seems there are almost no nose heavy Waiex out there.

1. I have decided on an airmaster prop and it is 28 pounds right on the nose.
2. My engine mount is about 4 pounds heavier than the typical sonex mount.
3. I am putting the batteries, fuel pumps, and smoke oil tank under the cowl.
4. This is a B model. There is less data that I could find, but it seems the b model has a little bit more weight up front than the a model.

For my mission I don't need two full size adults and baggage and full fuel in the plane. I have young kids and my wife doesn't like to fly with me much right now on account of the kids. Even if she did she is small. If my kids come, I have at least 5 years before one of them is going to weigh 100 pounds. Most of my cross countries will be solo. Since I will be running mogas having the ability to load up solo and extend the range would be very nice. If I was running 100LL and/or had better availability to mogas I might not do this. Also, I figure If I want, it is easier to remove one that's there than add one later.