It's very interesting to note that for the first years of production, the car was still called the DKW-IFA F9, acknowledging the origins of the vehicle.
English translation:
DKW F9 – the powerful new personal car from IFA
Senior Engineer Siegfried Rauch, IFA-Chemnitz
Kraftfahrzeugtechnick Bd.1. Nr 3 March 1951. Pg 59-62
When a small group of men spoke a few years ago about the fact that in the not-too-distant future the nationally owned vehicle industry would once again be manufacturing mass-produced passenger cars that would be on a par with the international standard of automotive technology, their optimism was widely laughed at. The IFA's DKW F 9 is proof of the correctness of our economic and socio-political path, proof of the professional skills of the workers, technicians and engineers in our state-owned companies. The fact of such a constructive achievement a few years after the total collapse [ie, Germany’s defeat] and defiance of the German-German split. The bottlenecks caused by the [division of the] country open up positive prospects for the five-year plan that has begun.
International technical development has not stood still. The demands placed on a modern, small car in terms of road holding, driving comfort and average route performance have become higher. The nationally owned vehicle industry should therefore create a new car that meets these requirements.
The task given is not easy to solve for various reasons. Above all, the new type had to be superior to the old F 8 in the most important features. The IFA has undoubtedly achieved this with the F 9. Yes, a whole new class of vehicle has been created, a small car in terms of displacement, weight and fuel consumption - with the performance of a mid-range car! And this explains the fact that, in addition to the F 9 as a very small car, the F 8 can be built even further, because the F 9 attracts a group of users who were previously dependent on mid-range cars.
It has often been criticized that the IFA showed the F 9 at a time when series production had not yet started. However, this criticism did not influence the responsible men of the state-owned vehicle industry. The F 9 did not go into series production until it was really ready for series production.
Engine
The fundamentally new design direction of the F 9 is particularly evident in the engine. The engine, which is no longer installed transversely but in the longitudinal direction of the vehicle (Figure 4), is of course a three-channel, two-stroke engine with flat pistons and reverse scavenging, which has been proven hundreds of thousands of times in terms of simplicity of construction, performance and economy. Three cylinders are combined into one block and result in a total displacement of 900 cc, so that per cylinder with a 70 mm bore and 78 mm cylinder, the displacement of 300 ccm, which experience has shown to be favorable for small, slow-running two-stroke engines. In contrast to its predecessors, the engine of the F 9 does not have a separate crankcase, but only an end-trough screwed from below against the cylinder/crankcase, which forms three separate crankshafts with the upper part, in which the crankshaft is cranked three times at 120° each (like previously pressed together hydraulically from individual parts), runs in roller bearings. The chambers are sealed by contact made on the bearings by labyrinth rings and on the end chambers by rubber sleeve seals. The connecting rods also have roller bearings, while the piston pins are secured in the usual way in the light metal piston with a non-stick pin and laterally secured by snap rings.
The arrangement of the control slots in the cylinders is known from the earlier reverse-scavenging engines - clever, mutual offset of the flushing axes of the cylinders results in a short design of the entire engine and the redesign of the inlet cannula on one side and all of the outlet cannulas on the other side blocks.
The light metal head has hemispherical compression chambers, the contents of which are dimensioned in such a way that a compression ratio of 1 - 6.25 results, with which the engine runs smoothly with only moderately knock-resistant fuel thanks to its favourable flushing conditions. The fan shaft is placed through the head, which is driven by the triangular V-belt drive with the 190-watt alternator on the left and on which the four-bladed fan sits at the rear, where the oversized radiator is placed behind the engine to fit to the curved form of the body (total contents of the radiator system is 10 liters) supplies the cooling air and supports the thermosiphon cooling, which is sufficient under all conditions.
Ignition takes place via the 18-mu battery-powered plugs located diagonally on the side of the head; a spiral worm gear at the front of the engine drives the distributor. The ignition coil is also attached to the engine, while the 0.6 hp starter is arranged on the right side of the engine in the usual way so that its pinion engages in the flywheel teeth. It might be interesting to know that the entire electrical equipment of the F 9 is the product of state-owned industry.
The fuel-air mixture for the engine is prepared in a horizontal float carburettor, which is located on the engine block with an updraft wet air-filter and intake silencer set on a distributor piece that has been carefully designed to ensure the same mixture ratio [is distributed to each cylinder] and is equipped with an automatically switched-off starting device. It is also a product of the state-owned industry (BVF) and plays a key role in the favourable fuel consumption values of the vehicle. The fuel is supplied via gravity feed, so that all sources of disruption associated with [fuel pump] pressure delivery are avoided.
This engine also has the proven mixture lubrication, i.e., the engine oil is simply mixed into the fuel when refuelling in a ratio of 1:25 - everything else then happens automatically in the engine. The technical and economic advantages of mixture lubrication are demonstrated again in this powerful engine.
A collecting manifold on the left side of the engine leads the exhaust gases to a common pipe, then to the large-sized exhaust muffler, which is perfectly coordinated with regard to dynamic pressure, and from there, in an arc over the rear axle, to the end of the car.
In the frame, the engine or the entire engine block is suspended on rubber blocks at three points. At a speed of just 3600 rpm, it delivers a guaranteed standard average power of 28 hp - a value that alone doesn't mean anything. What is important is the course of the torque or power curve over the entire speed range, and how favourable this is shown by the behaviour of the engine in practical operation, i.e. its liveliness and elasticity even at low and medium speeds.
Gearbox and power transmission
The flywheel located at the end of the crankshaft carries a dry single-disc clutch from which the power is transmitted to the change gear. In order to achieve the highest possible load on the driven front wheels on the one hand, and on the other hand to concentrate the entire engine close to the drive axles, the arrangement in the clutch/gearbox housing (Figure 2), which is made of cast light metal, is such that in the middle bevel gear differential with the two side drives from which the clutch and the four-speed gearbox are located behind the differential. The freewheel is located at the end of the housing.
The power flow runs from the clutch over the differential shaft into the transmission main shaft, from there via the respective gear set to the secondary shaft, which carries the drive pinion for the differential ring gear. The four forward gears are designed in such a way that the first and second gears (and of course also the reverse gear) have toothed shifting by sliding gear wheels, while the third and fourth gears use helical, double-mesh and dog-sleeved gears.
The clamping roller freewheel, which can be adjusted using a hand lever below the steering column, is very powerful. The locking required when reversing occurs automatically from the shift rod guide located on the side of the transmission housing. The shift lever, which leads upwards from there, is moved horizontally and vertically into the various shift levels by a hand lever located in the middle of the dashboard and is ready to hand via a shift rod - similar to the one used on the F 8. The lubrication of the change gear and differential gear as well as the freewheel is carried out through the gear oil, i.e. no longer through the grease/oil mixture used for the previous DKW types.
On the side of the transmission housing, i.e., there are encapsulated rubber joints similar to those of the F 8, into the grooved outer part of which the cardan shafts are inserted, which direct the driving forces on both sides via the wide-angle joints, also known and proven from the F 8, located in the gear oil bath, to the front wheels; Because the F 9 is a front-wheel drive car with all of its well-known advantages, which are even increased by the more favourable load distribution. This means that the entire interior of the F 9 remains free from a transmission tunnel. It is obvious that the concentration of the entire engine in the front part of the car is also advantageous in terms of noise and from this point of view underlines the superiority of the F 9 over rear-wheel drive vehicles.
Chassis
At first glance, when looking at a picture of the chassis (Figure 3), it seems as if the engine described above is simply suspended in a normal F-8 frame: unmistakably the front transverse spring, the bulged, stiff profile tube frame and the rigid rear axle with the high-lying transverse spring, which results in the so-called "floating axis"; an arrangement in which the structure "hangs on the spring" so to speak and therefore does not show any lateral tilt when cornering.
But if you look a little more closely, you can see that while retaining a few basic features, the co-designers have created something new here. Firstly, there is the wheelbase, which has been shortened by 250 mm to 2350 mm. This was possible despite the requirement for an enlarged interior space by moving the engine block forward and results in the F 9's even improved road handling, especially in curves, which has effective travel averages over 80 kph on busy roads, such as Chemnitz-Berlin, i.e., not only motorway speeds is possible safely, which has been proven repeatedly by the test cars equipped with special permits and completely standard equipment. While the arrangement of the rear axle, including springs, shock absorbers and longitudinal steering, corresponds absolutely to that of the F 8, the front suspension is significantly different. It is not only that the rack and pinion steering with the tie rods had to move behind the spring - what is particularly important is that the motor wishbones no longer use the shock absorber axle for steerage at the same time, but are mounted separately on the frame, forming a much wider triangle, while the spring dampening is carried out by telescopic shock absorbers that are not linked to one of the wishbone arms.
Drive high average speed safely - this of course also requires brakes that provide the best deceleration values. That's why the F 9 was equipped with a hydraulic brake, which is normal in terms of the design of the wheel brake cylinders but has a completely new design in the master brake cylinder and is again a product of IFA. The handbrake acting on the rear wheels works with a cable pull. The handbrake lever is arranged in such a way that it does not hinder getting in and out and is still within easy reach.
Body
When creating the body (picture l), new approaches were taken compared to previous types, both in terms of material as well as shape and equipment. The artificial leather-covered plywood body was replaced by an all-steel version, which was particularly required in the export business. And not only is a pleasant design, but technically correct as well as tastefully appealing, modern, if not fashionable,
While the shape always receives honest recognition, it is also the surprising spaciousness of the car. The comfortable seating arrangement (front seats can be moved individually), the convenient position of the steering wheel and the proximity of all control levers, the excellent view of the road - in all these details the vehicle reveals how much experience the designers have put into it. It can't be the point of a technical description to list details in a brochure - but it goes without saying that seemingly small details, such as the bonnet, which can be locked from the inside, or the spacious trunk, which is accessible from the outside and inside, and the spare wheel - separated from the luggage records, are particularly important where our nationally owned industry faces competition from high-quality motor vehicles from other countries. The favourable assessment of the F 9 abroad also proves that it is absolutely competitive in exports.
IFA-DKW F9 brochure:
https://dkwautounionproject.blogspot.com/2023/12/1949-ifa-dkw-f9-brochure.html
Development of the IFA F9:
https://dkwautounionproject.blogspot.com/2020/07/the-development-of-ifa-f9.html
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