Menu Sign In Contact FAQ
Banner
Welcome to our forums

Lancair 200-360 fuel system

Posts moved from the PA28 fuel system thread

In the Lancair 235-360, it is common to have a header tank feeding the engine. The fuel in the wing tanks are simply pumped into header tank, and many have only fuel gauge in the header tank, none in the wing tanks.

The elephant is the circulation
ENVA ENOP ENMO, Norway

many have only fuel gauge in the header tank, none in the wing tanks.

How does that work, for flying somewhere? Do they all have a totaliser, and a means of timing which tank was selected for how long?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

How does that work, for flying somewhere? Do they all have a totaliser, and a means of timing which tank was selected for how long?

Not sure, dip stick? I will ask one of the owners here when I bump into them. I think the header tank is about 8 gallons, so you got around an hour. The header tank work as a kind of totalizer. I think the original setup shows a red light when at a certain level, then switch on one of the pumps until it is full (starts to flow out of the header vent). It’s a very simple system. Not sure if the later built even have a header tank.

The elephant is the circulation
ENVA ENOP ENMO, Norway

I think the original setup shows a red light when at a certain level, then switch on one of the pumps until it is full (starts to flow out of the header vent). It’s a very simple system

That sounds like a joke…

For example if the lamp fails, the engine just stops.

I vaguely recall somebody telling me of one of these types getting an engine stoppage after 30 mins of flying, due to some fuel system issue, and maybe it was a similar system on which the lamp was blown? I did a google and found this relating to a similar type. Also here on page 3.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

That sounds like a joke…

For example if the lamp fails, the engine just stops.

There is also a gauge Originally the gauge is just a transparent tube, like on old Cubs. It’s very simple, but it works. It seems that originally the header tank is enough for a small gravity fed carbureted engine, and the transfer pumps are used to pump fuel to the header tank. With larger engines and FI it seems to me the idea with the header tank is just a complication. There is more than enough fuel in the wing tanks for a more common setup. If I were to build a Lancair today, I’m not sure how I would do it, keep the header tank or not. A more practical setup would include return line(s) to the wing tanks, but that is also a bit complex.

The elephant is the circulation
ENVA ENOP ENMO, Norway

Presumably therefore if you didn’t know about the header tank, the engine will stop when the header tank empties?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Presumably therefore if you didn’t know about the header tank, the engine will stop when the header tank empties?

Yes, so it seems. If you forget about transferring the fuel to the header, it will run dry in an hour or so. It wouldn’t be too difficult to make an automated system, but the more I think about that header tank, the more odd the whole concept seems. If you absolutely need that extra 8 gallons, it would be better to transfer (by gravity) from the header tank to the main tanks instead, and run a normal setup from the mains. There are two Lancairs here at ENVA. One of them, a 235 has this header tank setup. He told me he always fills it up before shutting down so he don’t have to use battery power alone to transfer fuel before starting. The other, a 320, I’m not sure what he has. The 320 is a considerable heavier engine than a 235, maybe the COG would prevent a 320/320 from using a header tank?

Googled this accident report from Australia. It is a bit interesting.

The aircraft was constructed by an owner-builder in Western Australia from a kit
purchased from the manufacturer in the US. The builder fitted a type-certified9
Textron Lycoming O-360 engine and type-certified MT-Propeller MTV-12 variable
pitch propeller. The kit did not contain a stall warning device and the builder did
not fit one. There was no regulatory requirement for a stall warning device.
The builder reported that the aircraft was constructed in accordance with the kit
plans except for a few changes that included modifying the fuel system. In the
standard fuel system, a header tank located between the cockpit and engine was the
only tank that supplied fuel to the engine. When the header tank quantity decreased,
the pilot transferred fuel from the left or right wing tank to the header tank by
activating electric pumps. The builder reported that he had been concerned that with
a standard fuel system, a pilot could forget about the need to transfer fuel to the
header tank.
The builder modified the standard fuel system by incorporating a fuel selector
(figure 5) and fuel lines that allowed the engine to be supplied directly from the
header tank or either wing tank. An electric pump and fuel lines were also fitted to
allow transfer of fuel from the left wing tank to the header tank. The header tank
had a maximum capacity of 41 L and each wing tank had a maximum capacity of
80 L.
The aircraft builder reported that he operated the aircraft with the header tank
selected for takeoff and climb, and selected a wing tank during the cruise phase of
flight. Information relating to the nature of the modification and the proposed
method of operation was not included in any aircraft documentation.

The aircraft was equipped with a plastic-tube sight gauge as the header tank fuel
quantity indicator. The fuel level evident in the plastic tube corresponded with the
quantity of fuel in the header tank. There were marks identified adjacent to the
plastic tube, but no scale marked. An electronic instrument provided fuel quantity
indications for the left or right tank.
A copy of the Pilot’s Operating Handbook and Airplane Flight Manual
(POH/AFM) produced by the kit manufacturer for Lancair 235, 320 and 360 aircraft
was carried in the aircraft. It contained the following fuel management information:

Do not takeoff with less than 8 gallons [30 L]10 in the header tank. Since the
engine is supplied fuel solely from the header tank, fuel must be transferred
from each wing tank to the header tank periodically

The minimum fuel instruction was also placarded on the aircraft’s instrument panel
(figure 6). According to the aircraft kit manufacturer, the 8 gallon minimum for
takeoff was to ensure that pilot had adequate fuel for takeoff and climb, and was to
keep the aircraft within centre of gravity limits.
The POH/AFM fuel management information and instrument panel placard did not
apply to the system in VH-ZNZ because fuel was not supplied solely from the
header tank.
The elephant is the circulation
ENVA ENOP ENMO, Norway

What is the reason for the header tank, when there are plenty of planes with same or similar engines which just suck the fuel up with an engine-driven fuel pump?

and have an electric one as a backup

Even if the header tank refill was automated you would still need two electric pumps, because if one fails you will likely have insufficient endurance to reach the nearest airport, and an off-airport landing in one of these types is not a great idea.

Administrator
Shoreham EGKA, United Kingdom

The Dragonfly home built had a similar header tank arrangement with a single fuel pump and about 45 minutes range on the header tank. It worked pretty well and eliminated one pump.

The fuel circulated continuously in that system, maintaining a constant level in the header tank without any action from the pilot. If the header tank fuel level dropped for any reason, you landed.

Peter wrote:

What is the reason for the header tank, when there are plenty of planes with same or similar engines which just suck the fuel up with an engine-driven fuel pump?

Not sure the exact reason on the Lancair, but the general reason is to have gravity feed of the fuel to the engine. Gravity never fails, so you have no direct dependence on fuel pumps. A transfer pump failure will give you at least 20-30 minutes of endurance.

The elephant is the circulation
ENVA ENOP ENMO, Norway
15 Posts
Sign in to add your message

Back to Top