Anyone experienced on SF 260?

[hugh flung_dung]

Apologies for intruding, but this seems like a good place to ask for advice on the Siai Marchetti SF260. I've just started flying an SF 260B. It appears to be a very straightforward aircraft but if there's anyone out there (US mil?) with a lot of experience on type it would be good to benefit from some words of advice or caution.

HFD

[NutLoose]

HFD


If it's of any help I know the pilot that has been flying the BMI one for many years, indeed they have a replacement for theirs that has just arrived in the UK from the US and I believe their older one is up for sale. ( G-BAGB )

I will let him know you have posted this thread if you wish.

[MrBernoulli]

Long time since I flew the SF260! Last flew in 1980 or 81, but I did fly both the 'vanilla' military trainer and the ground attack version (both Lycoming piston powered). About 245 hours total time. Not sure how I can help but let me know what you want and I'll wrack my brain!

[Argonautical]

You could also ask on the African forum because the Rhodesian air Force used to use them where they were called Genets.

[hugh flung_dung]

Thanks for the replies so far.

What I'm looking for is info about any particular vices, or things that "everyone knows" about the type so I can explore the darker corners of the envelope before my students take me there unintentionally. Examples might be: any particular tendency to spin from manoeuvre; whether the spin tends to flatten under certain circumstances, or be hyper-sensitive to a little aileron input, or can cross-over to inverted during an over enthusiastic erect spin recovery; specific things to watch for during the walk-round; engine handling do/dont, prone to carb icing, ... etc. etc.

One of the peculiarities of the (translated) PoH is the after take-off check: "A few seconds after take-off, retract the landing gear. About 8-10 seconds later check that red landing gear indicator light is ON; in case the red light indicates the landing gear in movement, it must be OFF". I can't find any systems diagrams, but I assume that the red light indicates that the pump is running and that what the PoH means is that the transit light should go out after 8-10 seconds. Is this correct?

HFD

[MrBernoulli]

hugh,

All that below appiles to the piston-powered SF260M and 260W - I did one ride in a turbo-prop version but have no real experience of that:

I'm sure the gear was electric? So no pumps, but an electric motor. The red light (like a lot of basic systems) merely indicates that the gear is in transit - neither locked up, nor locked down.

If the red light remains on after a retract then you must assume that some part of the gear or gear door is still hanging in the breeze and observe any speed limit. Just occasionally, very occasionally, the red on our SF260s would not go out after a retract. We gained some height (within the gear speed limit - can't even remember what it was) and did a 'smart' and quick push in the control column (momentary negative G) which 'tucked' the gear up and the light went out. One had to tell the engineers later as it likely meant that the up-lock microswitch needed adjusting, or similar.

For a gear lowering problem, I think you isolated the gear electrics with the circuit breaker, removed the cover over the manual gear handle (between the seats) and wound the gear down. Took quite a while, and a fair bit of effort - something like 24 rotations (?) of the handle - the last 3 or 4 rotations were really physical as you had to ensure the legs were (geometrically) locked down. I can't recall whether you then placed the gear switch in the down position and then reset the CB - you'll have to read your handbook. Throughout all this you still needed to maintain a lookout and fly accurately too! Aviate, Navigate Communicate !!!!!!!!!!

Worth remembering that a lack of a green gear light doesn't necessarily mean the gear isn't down and locked - it sometimes indicates a blown bulb! Easily verified by using the press-to-test facility on the light holder and ensuring that the night dimming iris on the bulb cover isn't closed off (rotate the light outer cover). I f you suspect the bulb is blown then you could fit a replacement, or swap with a good bulb from elsewhere/other gear leg (once you had confirmed that the other leg was locked down of course!). Don't drop the bulbs in the cockpit now!

Spinning, as I recall, was pretty rapid in rotation but consistently stable. Whilst not necessarily recognised as a 'proper' recovery drill in the training world, if you let the controls go the SF260 would always recover itself from a spin. Some aircraft, like the RAF Bulldog, wouldn't always recover from a spin if the controls were released. Of course, always better to train for, and practise, a standard spin recovery drill. I have vague, very vague recollections of inverted spinning ..... but I may be confusing the SF260 with another type I have flown, not sure. No spinning with pax/baggage strapped in to the rear '3rd' seat, or with fuel in the generous tip-tanks, if I remember correctly.

What was noticeable about the SF260 compared to, say, the RAF Bulldog, was that it was easier to unintentionally get it into the spin 'regime' when manoeuvring hard or doing aerobatics. I guess this is because the SF260 has a much more 'critical' wing than most basic trainers. The wing is designed more for speed (a slick little ship!) so as soon as you load up the wing by hard manoeuvring you'll induce buffett sooner than most training aircraft - it takes little more G or pulling on the control column for it to depart and possibly spin. I learned to fly from ab-initio on the SF260, so I didn't have other aircraft to compare it with at the time, and therefore quickly learned to respect the corners of it's flight envelope. Students coming from other aircraft to the SF260 will need to be careful of that - it is not as forgiving if you push it to the edge. Still a very nice, great-performing aircraft, but you need to respect it- it can bite.

Like all retractable gear aircraft in the training world, you must drill the gear procedure until it becomes second nature. Again, students coming from a non-retractable aircraft are in danger of landing wheels-up if it doesn't get 'hammered' in to them! I am pleased to say that no student pilot up to the time I qualified for 'wings' ever landed wheels-up, even though we had not flown other aircraft. Checking the gear was down and locked was drilled almost religiously. Sadly, I recall at least one qualified pilot landing on the gun (or was it rocket?) pods of an armed variant after a ground attack training sortie. Save yourself, and remember something simple like "Gear, Flaps, Feet Off the Brake Pedals, Landing Clearance" - it works for pretty much all aircraft. You may wish to add "Park Brake Off" as well - it has been done!

With respect to engine handling, our SF260s did occasionally stop during aerobatics that involved any fairly prolonged negative G. We were operating from high-ish altitude runways (just shy of 5000 ft amsl) and in a hot climate, so that didn't help, but in a basic carburettor aircraft if you push neg G, the carb float moves UP and shuts off the incoming fuel. Give it long enough and the carb fuel bowl is drained ....... and the engine stops. We learned to live with it ..... and always performed aeros etc from a height which allowed recovery to a glide and plenty of time to crank it up again, which it did easily. I feel that far too many civilian training organisations do spinning and aeros too low - not clever.

The dust of my memory is steadily clearing, but it was a long time ago - hope this all helps. Feel free to ask more - I'll help where I can.

:ok:

You may find these sites useful/of interest:
SIAI Marchetti light aircraft home page (http://www.siai-marchetti.nl/)
http://www.geocities.com/Nashville/7348/index.html

This following is the SIAI-Marchetti SF-260 Owner's Association Discussion Forum - got to be worth registering and getting stuck in!
Log In (http://sf260.org/MOAForum/)

[hugh flung_dung]

Thanks MrB, especially for the links.
With the emergency gear lowering system electric gear makes more sense than the electro-hydraulic power pack (a la PA34, BE76, etc) that I thought was fitted (it's 25 turns BTW, so your memory isn't too bad).

HFD