NorFlyer wrote:
As for the fuel system I don’t think it’s that bad. You have the tip tanks with 18 USG each and the mains holding 12.7 each.
My interest there would be avoiding restart issues after potentially running a tank dry, especially with an injected engine. I know the early ones were carburated, which would make this less critical. The aforementioned hangar neighbor has a lot of experience on type and says you learn to watch the fuel pressure carefully and switch before a tank runs dry. His is injected with the later fuel system and he described his fuel management process to me: take off on a wing tank, switch to both tips for cruise, then to the remaining wing tank for landing. The independently valved early system would presumably be the same except for managing tip tanks in cruise, which due to balance issues sounds like it might be a bit fiddly.
A guy here killed himself by taking off on tip tanks, which I understand to be incorrect practice and I guess also highlights the importance of switching to a wing tank for landing, in case of a go around.
I think I could handle all of the above, as long as I was starting the flight with wing tanks full 
Thanks much for posting the fuel system diagram, I’m interested in learning more as time goes on and appreciate your posting about your exciting project.
The local guy has also flown the turbine version and described the fuel management situation on that one, sounded similar to a fighter jet in terms of needing careful planning, but notwithstanding a couple here owned by civilians this is really a military focused variant.
Having flown every model of the SF260 totalling 3000+ hours and including 3 transatlantic crossings (with a 5th ferry tank) I can assure everyone that running a tank dry is never a problem in the Marchetti, unless you are fast asleep at the time. On all models with the 4 or 5-way fuel selector, that’s the A to D series, whether carburetted or injected Lycoming 540, it’s pump on then change tank; and unless you have left it so long that the prop has stopped windmilling, a restart is pretty well instantaneous. But that’s the same with any aeroplane with more than one fuel tank!
The Flight Manual for the A to D models mandates using the inboard tanks for take-off and landing but that is pretty well standard practice for any aircraft with a simple 4-tank fuel system. It’s because 1) they are closest to the fuel pumps and 2) don’t suffer from fuel starvation when you accelerate and climb with a low fuel quantity in the tip tanks which because they are much longer than the inboards, and with a central fuel pick-up, can result in fuel starvation at low fuel level and high angle of climb or acceleration.
The E and F models, which have only ever been sold to the military, have the same fuel system as the Turbine SF260TP where a fuel transfer pump feeds fuel to an inboard tank automatically. If the transfer pump fails you have to select the emergency setting which is just one inboard tank and at best 48 litres usable which is still 40 minutes endurance (except on the TP..
There is one gotcha, which I only discovered when I lent my Marchetti to a great friend who was an enormously experienced warbird display pilot without covering it in the briefing. The fuel selector handle is a beautifully crafted piece of Italian workmanship, the short pointed end of which shows which tank is selected .The long end of the handle points to the tip tank on the other side .I had filled the inboard tanks for him and left the tip tanks1/4 full; he took off on the left tip tank, thinking it was the right inboard and the engine stopped during his first loop…..fortunately he had the presence of mind to understand what was happening and all was well. I now always cover that scenario when introducing someone to flying a Marchetti.
On long trips I balance the tip tanks every 15 minutes, not having an autopilot you can feel the lateral imbalance which prompts you to change to the other tip tank. When they are getting very low, just watch for a fuel pressure gauge quiver and then change to the opposite tank. Murphy’s law always seems to dictate that just as a tank is about to run dry you get a new ATC clearance which diverts your attention until the engine runs down….it wakes up the Mrs who is normally dozing by then!
Marchettiman wrote:
On long trips I balance the tip tanks every 15 minutes, not having an autopilot you can feel the lateral imbalance which prompts you to change to the other tip tank.
Neat. I’ve found that with many things mechanical, old and Italian, you find that some unusual feature works very well only after trying it. Another example is cars with steering wheels angled so your hands are at 4 and 8 o’clock in cruise.
It occurs to me that 15 minutes is about 17 lbs or 7.5 Kg of fuel no longer pushing down on the very end of wing tip. It makes sense that you can feel it through the stick.
Beautiful endeavour! Best of lucks with your project. Enjoy the way…and the goal!
Just a quick update. She has been unloaded and moved to our backshop. Everything held up well on the trip home. Instrument panel has been removed and stripped so we can get the new one CNCed next week. Our avionics guy has a lot of work ahead of him. Engine is in for overhaul. Propeller is crated and ready to ship, but we are contemplating upgrading to a three blade MT instead. The hub overhaul is quite pricey (AD/SB).
Interior has held up suprisingly well considering it has been sitting since 86.
Nice project. Any updates?
Yes, there is progress. Although slower as the holiday is near.
We have most of the plane picked apart and getting it, and all the components ready for primer, paint and/or powder coat. Engine is in for overhaul. New MT prop is on order. Most of the bits and pieces are ordered and coming in as we speak. We are doing a few custom bits and pieces which takes a lot of time to design. Most of the avionics is already in the shop, except for a few backordered items (long lead time on G5’s these days). The avionics guy has started mocking up the panel and drawing new wiring diagrams. Think we have settled on a final panel design.
Still aiming for the May timeframe for first flight, but the clock is ticking fast :D
I’ll attach a couple of pics from yesterday and will try to post another update before the holidays.
Have a nice weekend!
Nice work!
In case you are not going for brand new perspex for the canopy, may I recommend some stuff that does an amazing job to polish out light scratches:
I’m fanatic to keep the windows in perfect shape, not only to keep that “as new” experience of an aircraft, but also for safety reasons.
Thanks for the suggestion. The canopy is in pretty good shape, but needs a polish! Hand/machine (rpms etc)?
Nice Swift on the can of polish
In the next couple of weeks a friend and I will be cutting and grinding out my windscreen in preparation for gluing in a new one. It lasted 50 years and is only slightly translucent, not scratched, but anything you can do to avoid doing this work is a good idea in my book. I’m dreading it, mainly the risk of breaking the replacement.
Looks like work is progressing nicely on the Marchetti. The one typically located a few yards from where I’m sitting as I write this has flown off for a few weeks, and temporarily in its hangar is a Pinguino undergoing a few odds and ends repairs, also nice to see.
