Rare Aircraft – Interavia I-3, 9A-DOG

By Boran Pivčić
All photos author

The I-3 is just one of those birds that so liven up a day at the airfield. An imposing Russian radial aerobatic monoplane, usually in a catchy scheme, is not something you casually glance over – especially when it fires up that big tractor under the hood amidst clouds of white smoke and the stench of engine oil. 9A-DOG is no different, though there is a bit more to it than it seems.

1. The I-3 – a bit of history:

Though outwardly very similar to the Sukhoi Su-29 – almost identical at a glance – the I-3 is a different machine altogether. Known in Russia as the Technoavia SP-91 (the I-3, or sometimes E-3, being the export designation), it was designed by Sergey Estoyan, the same man who did the Su-26/29/31 aerobatic series, after he left Sukhoi to co-found Technoavia. First flown in 1993, the I-3 was intended to be a cheaper, somewhat softer version of the Su-29, but one still capable of successfully competing in Unlimited Class aerobatic competitions. In the event, the aircraft didn’t prove to be much of a sales success and only about 20-ish were ever made (23 springs to mind, but I can’t verify that), of which 10-12 are estimated to survive today.

Like other Russian aerobatic aircraft, the I-3 uses the well proven formula of a strong, survivable taildragger airframe with tandem seats under a one-piece canopy – though interestingly, the I-3 can also be converted to a single-seat configuration, something unique in the aerobatic world. And it even has a small baggage compartment! The power comes from the extremely reliable and much-loved Vedneyev M-14P 9 cyl radial, producing 360 HP in this instance (though the westernised I-3M had the option of a more powerful 400 HP model), usually driving a three-blade constant speed prop.

Performance-wise, you can hit the usual +11/-9 G with two occupants, and I think the pilot of 9A-DOG told me the ultimate limit load is a juicy +/-18 G (but still not as impressive as the Su-31’s insane +/-23 G). Roll rate is not disappointing either, to say the least, at 345 deg/sec – almost a full roll in one second. Fuel consumption – we’ll skip that :). Oil consumption… well, despite the M-14 not being oil-thirsty, the pilot of 9A-DOG – who used to own a Yak-52 with the same engine – told me once the engine uses a liter per hour in aerobatic flight… so judge for yourselves :).

2. 9A-DOG – an overview:

9A-DOG – continuing the animal theme set by the aformentioned Yak-52, 9A-BUG – is an early model I-3, built in 1993, the type’s first production year. It had previously flown in the US where it suffered an accident and was rebuilt before being sold to Croatia in 2006. It is permanently based at Lučko and is a frequent visitor to many local airshows (being the only fully aerobatic – not to mention Unlimited Category – aircraft in the country).

Warming up prior to one of its first flights in Croatia. Image taken on June 14, 2006., a couple of days after arriving at Lučko

Warming up prior to one of its first flights on the Cro register. Image taken on June 14, 2006., a couple of days after arriving at Lučko

A WW2 fighter-ish sight, one could almost mistake it for a Lavochkin La-5 or -7 :)

A WW2 fighter-ish shape, one could almost mistake it for a Lavochkin La-5 or -7 🙂

The I-3 is imposing whichever way you look at it

The I-3 is imposing whichever way you look at it. Note the thin - but strong - main gear legs, needed to provide adequate ground clearance for the large-diameter prop

Pulling out of a loop - a wow! in Croatia - at a local airshow

Pulling out of a loop - still a "wow!" in Croatia - at a local airshow

Nose detail. The characteristic Russian cooling flaps can be seen here easily. Unlike the shutter versions on the Yak-52, these open radially, a visually cleaner solution

Nose detail. The characteristic Russian cooling flaps can be seen here easily. Unlike the shutter versions on the Yak-52, these open radially, a visually cleaner solution. The prop is I think an MTV-9 model

Inside, the seating is typical an aircraft of this type – passenger up front, pilot in the back, to keep the center of gravity well back. This makes the aircraft unstable around all three axes – but since stability is inversely proportional to maneuverability, that’s the point. Interestingly, the panel is quite spartan even for an aerobatic aircraft, as it’s fitted with an innovative MFD screen that shows all flight-relevant data (the panel received an upgrade since the last time I saw in in 2006., but didn’t check out what – yet).

The simple & clean panel includes just a MFD, GPS and backup compass, as well as a basic radio suite

The simple & clean panel includes just a MFD, GPS and backup compass, as well as a basic radio suite

All in all, the I-3’s rarity meant I had to include it here at some point :). More pictures may be forthcoming as soon as I take them, as the airshow season is heating up along with the weather – and combined with my new 100-400 mm lens, you may get to see some actiony shots as well…

This just looks right

This just looks right 🙂

Specs (flugzeuginfo.net): http://www.flugzeuginfo.net/acdata_php/acdata_technoavia_sp91_en.php
I-3M specs (YAK North America): http://www.yaknorthamerica.com/i3mspecs.htm

The owner's former Yak-52. Now flying in Portugal as RA-3466K with a four-ship aerobatic team

The owner's former Yak-52. Now flying in Portugal as RA-3466K with a four-ship aerobatic team

Closeup of the front. The deep blue really suited this aircraft, one of the best - if not the best - paint scheme I've seen on a -52

Closeup of the front. The deep blue really suited this aircraft, one of the best - if not the best - paint scheme I've seen on a -52

3 thoughts on “Rare Aircraft – Interavia I-3, 9A-DOG

  1. I am buying probably the last remaining Interavia I-3 kit as we speak, and would like to know if you have contact details (email preferably) for the owner of your local I-3 , 9A DOG

    Cheers

    Martin

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