I-153DM by themindseye

Last crawled date: 3 years ago

I-153DM
Supplementary Motors (i.e., Dopolnityelnyi Motor - Dvigatel' Merkulov = DM) designed by I.A. Merkulov in 1939
I-153DM (Dopolnityelnyi Motor – supplementary engine) - An I-153DM was experimentally flown with gasoline-burning ramjet engines under its wings. At first, smaller DM-2 engines were tested and they increased the top speed by 30 km/h (19 mph), later more powerful DM-4 engines were added which obtained as much as a 50 km/h (31 mph) speed increase. A total of 74 flights were undertaken.
There were various models of ramjet engines:
DM-1: 200mm gasoline AV fuel, 1939.
DM-2: 400mm gasoline AV fuel, 1940.
DM-4: 500mm 30kg gasoline AV fuel supplemented with ethyl alcohol, 1940.
DM-4C: DM-4 variant for Yak-UTI, 1942.
On 3 September 1940, test pilot Piotr Loginov flew an I-153 (No. 6034) equipped with two DM-2 ramjets. Later on 3 October, Loginov flew the same I-153 refitted with the more powerful DM-4 ramjets. There were 20 flights recorded with the DM-4 and biplane, but these tests were stopped in December 1940.
The DM jet throat and nozzle were double walled with fuel circulating through this wall-cavity for cooling the ramjet. At the exit of this cooling circulation stage, the fuel was combined with air and sprayed into the interior of the motor. This flammable mixture was then electrically ignited for combustion.
The DM-2 had a diameter of 400mm, length of 1.5m and a weight of 19kg. The more powerful DM-4 saw its size increased to 500mm in diameter, length of 1.98m, and a weight of 30kg.
As the ramjet testing progressed, the rear fuselage and tail fabric of the I-153 were replaced with flush-riveted aluminum sheets. These sheets protected the airplane from the hot exhaust and flame that were ejected from the ramjet's nozzle.
While conducting test flights of the DM-equipped I-153, Loginov fired the ramjets in approximately ten second bursts. Both the DM-2 and DM-4 were able to increase the speed of the biplane, but fuel consumption was too high during these ramjet test operations. Furthermore, when not being used, the powerplants increased the drag on the I-153 and reduced the aircraft's maneuverability.
Scale DM-4
1/72
Diameter 6.9mm
Length 27.5mm
The Model
This model consists of only the DM-4 ramjets. You will need to purchase a 1/72-scale plastic model kit of the I-153 to act as a donor for incorporating the twin DM-4s into a "hybrid" model--part plastic kit and part 3D printed accessories. An ideal kit for this donor model is ICM I-153 WWII Soviet Biplane Fighter. You can purchase this model kit from here:
Scale Hobbyist #ICM 72074 $12.79
At: https://www.scalehobbyist.com/catagories/Model_Aircraft/i-153-chaika-wwii-soviet-biplane-fighter/ICM00072074/product.php
You will need to print two DM-4 models. Use a brim and secondary adhesive (e.g., glue stick) for printing these DM-4s.
Assemble each DM-4 with this parts order: intake nacelle (1), ignition ring (2), combustion chamber (3), and exhaust nozzle (4). Refer to the photograph for a label of these parts. The completed DM-4 is attached to the I-153 with the 3D printed support pylon (5).
You must prepare the I-153 kit with the following modifications:
Remove the cowl-mounted 7.62mm ShKAS machine guns (by carefully sanding them off).
Remove the underwing ordnance hard points (by carefully sanding them off).
The DM-4s are glued to the underside of each lower wing. The attachment point is 1mm inside of each main wing strut.
The completed hybrid I-153DM is painted overall aluminum with two red Soviet star decals (e.g., #4 from the ICM model decal sheet) applied to the fuselage sides. This kit is extremely small and can be very difficult to assemble--take your time and carefully follow the instruction manual that is supplied with the kit.
Finally, print the tarmac as a display platform for your finished model. Optionally, there is a lip on the back of the tarmac for attaching a 3D-printed "lithophane" background image. You might be able to locate a suitable image from here:
https://i.redd.it/gydpiehhg5wy.jpg
And just how small is this model? Refer to the photograph with the King Cake "Baby" for a size reference point. Tee-he. Happy Mardi Gras!
References
Gordon, Yefim and Keith Dexter, Polikarpov Biplane Fighter Variants, Wings of Fame, Volume 17, 1999, pp. 106–129. London: Aerospace Publishing. ISBN 1-86184-041-1. ISSN 1361-2034.
Gordon, Yefim and Bill Gunston, Soviet X-Planes, Midland Publishing, London, England, 2000; ISBN 1 85780 099 0.