KhAI-1 and KhAI-2, by I.G.Neman and L.Arson

36k b/w the first KhAI-1 prior its maiden flight (October 4, 1932). From 'Krylia Rodiny', January 1988;

In
May 1931 young professor of the Kharkov Aviation Institute I.G.Neman concluded his lecture with unusual offer:
- Does someone of present students wish to built a real aircraft?
As one could expect, there were no shortage in volunteers. Project of six-seat passenger aircraft was supervised by The Osoaviakhim Central Soviet of the Ukraine. Project had to be presented in February 1932 - designers had less than a year!
I.G.Neman decided to collect all progressive innovations in his project. After comprehensive analysis of existing aircraft and consultations with airdynamic specialists general layout became clear: single-engine low wing monoplane with clean cigar-shaped fuselage and retractable main landing gear. Main material - wood.
At early stages of the KhAI-1 project KhAI administration expressed some doubt in a success. Indeed, how the students will deal with up-to-date novelties and complex airdynamic problems? Some voices were raised in favor of more conventional design.
I.G.Neman reacted promptly: he split his students into two teams. One, lead by bachelor L.Arson, was working on advanced solution (KhAI-1), while another (bachelor A.Eremenko) was assigned to develop more conventional KhAI-2 with fixed landing gear.
Both projects were presented in time. Expert analysis proved advantages of KhAI-1, specially in speed and cost efficiency. KhAI-1 was approved for construction and financing for the prototype was obtained. In March 1932 blueprints were sent to Kharkov aircraft Plant. Designer General of the plant K.A.Kalinin supported young team. Technical and engineering personal (among them B.P.Lisunov) assisted in manufacturing and static tests of all aircraft systems and mechanics.
Many technological novelties were tried. For example, plywood stressed skin was shaped and glued directly on pre-assembled fuselage, installed on special support structure. This and other 'tricks' resulted in a record short prototype construction period - 180 days!
36k b/w the pre-series KhAI-1 during State Acceptance Trials (1933). From 'Krylia Rodiny', January 1988;
Technical data
Type KhAI-1
Function Prototype Series Passenger
Year 1932 1934 1936
Crew 1 1 1
Engines 1*480hp Bristol Jupiter VI 1*480hp M-22
Length 10.41m 10.26m 10.41m
Wingspan 14.4m 14.85m 14.4m
Wing area 34.5m2 33.2m2 33.17m2
Empty weight 1725kg 1630kg 1830kg
Loaded weight 2600kg 2600kg 2700kg
Wing load 75.3kg/m2 78.3kg/m2 81.4kg/m2
Power load 5.42kg/hp 5.42kg/hp 5.63kg/hp
Speed at 0m 292km/h 324km/h 313km/h
Landing Speed 98km/h 85km/h 105km/h
Landing Roll 240m 18sec
Takeoff Roll 330m 14sec
Range 820km 1130km 900km
Flight Endurance 4.6h 3.5h
Ceiling 7200m 7200m 6550m
Climb
3000m 12min
4000m 23 to 25min
Payload
Fuel+Oil 300 to 310kg
Seats 6 6 5
Cargo ?kg
On noon October 8, 1932 pilot B.N.Kudrin and designer I.G.Neman climbed into new airplane. First flight (just takeoff, circling the field and landing) revealed good handling, no problems were faced. But the key test took place later - in January 1933.
Despite landing gear retraction mechanism worked smoothly on the ground, I.G.Neman (secretly) took a set of tools for 'emergency extraction'. He never had to use it, thanks to reliable design. Once wheels were hidden in the wing, speed increased dramatically. Ground observers registered speed 292km/h - faster than any fighter in service at the time! KhAI-1 became first aircraft with retractable landing gear in Europe, and the first passenger aircraft with this feature in the World to be flown.
After factory trials, KhAI-1 was permitted to be flown to Moscow for the State Acceptance trials and production arrangements. Flight was performed on February 17, 1933 in record short time 2h54min with team of designers and all necessary documentation loaded.
During May-June 1933 State trials were performed by pilots I.F.Petrov and P.I.Stefanovskij. Their conclusion was positive, experienced test-pilots recommended KhAI-1 as a airplane of choice for GVF. Indeed, KhAI=1 was 50%+ faster than mass built at the time K.A.Kalinin K-5.
For KhAI-1 creation I.G.Neman was greeted by The Red Star medal.
42k b/w KhAI-1 of last production series (1936). From 'Krylia Rodiny', January 1988;

Before mass production (at Gorky Aviation Plant), some improvements were introduced. Rudder was area increased. Landing gear retraction mechanism replaced by more reliable, new lighter breaks equipped wheels had new shock-absorbing struts. Passenger cabin (2.7mx1.42mx1.8m) got more windows, lavatory, sound absorbing wall pads and better ventilation. Cargo section was enlarged. Weight saving efforts resulted in saving 125kg of 'dry' weight. Pre-production prototype was pushed to 319km/h by pilot T.S.Zhukov during factory trials.
Second batch of KhAI-3 was assembled in 1934- 1935 at Kiev Aircraft Plant. First aircraft built at this factory was flown in November 1934 by test-pilot V.G.Makarov. Passenger service trials started in April 1935 by Aeroflot pilot A.Grigoriev on line Moscow-Kiev. In the early 1936 regular passenger operation started on line Moscow-Sevastopol.
During intensive service two accident took place. Outer wing section broke off on takeoff and landing gear strut collapsed on landing few months later. To study and fix the problem OKO under supervision of V.K.Tairov was created. Several structural reinforcements resulted in empty weight increase, and one passenger seat had to be eliminated.
To verify efficiency of introduced modifications, 40 landings under different conditions were performed by pilots S.Tabarovskij and R.Kapreljan without a single problem. Production at Kiev was resumed.
Flight endurance was tested by S.Tabarovskij during long technical flight on September 3, 1937. 2375km on route Tambov-Rostov-Baku-Tbilisi-Rostov-Moscow were covered in 9 flight-hours.
43 KhAI-1 were built. They served on passenger and mail/cargo lines Moscow-Kharkov, Moscow-Minvody, Rostov-Krasnodar and some others until the end of 1940.
Naturally, it caught interest not only in civil aviation circles, and in 1935(?) I.G.Neman received military an order (or contract) to develop a high speed unarmed photo-reconnaissater (what became a KhAI-6/SFR).
PredecessorsModifications
None KhAI-1BB, KhAI-3
trainer-bomber

ReferencesLinks
  • "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.1 p.472-473;
  • 'Speedy passenger aircraft KhAI-1' by V.Savin, 'Krylia Rodiny', January 1988 pp.22-25
  • KhAI-1, Neman
  • KhAI-1 at Virtual Aircraft Museum
  • Created April 25, 1996
    Modified November 04, 1998
    by Alexandre Savine
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