Non-certified engine building
Besides certified Lycoming engines, their non-certified clones are manufactured in the U.S. or China for experimental aircraft. These are engines of similarly high quality, but unburdened with certification requirements, so the range of available models is broader and bolder than their prototypes.
These engines are as dependable as their certified "parents", and most of their components are approved by FAA as full-fledged equivalents under a PMA (Parts Manufacturer Approval). Ancillaries come from the same approved manufacturers and are fully identical to their prototypes.
We build these engines to your specifications.
Lycoming and Continental engine modifications
Many piston engines can be modified without losing their certified status. They can be converted for inverted flight, uprated or derated depending on the fuel to be used, etc. There are also non-certified modifications that can only be installed on experimental aircraft. For example, a Lycoming O-320 can be uprated to 165 hp, and a Lycoming O-360 – to 185 hp without reducing their service life, but with a limitation on allowed fuel grades. When combined with a properly chosen or suitably modified prop, these modifications can significantly improve the aircraft performance without requiring a lot of money for a different engine.
Samples of our work
Over a decade of work, we have built dozens of modifications, restorations and clones. Here are some of them.
Continental A65 (O-170), uprated to 95 hp, 2019
The Continental О-170 engine was mass-manufactured in the 1940s, produced 50 to 80 hp and weighed 70-72 kg. It had no alternator or dynamo. Early models were started by hand-propping or by pulling the starting cable from the cockpit; later ones had an electric starter. We bought several of these engines for restoration. Besides the standard overhaul, we implemented a few additional modifications:
1) These engines had no straight-through studs in the crankcase. This "teething problem", later addressed on O-200, caused a lot of nuisance: cylinder studs were developing slack and torquing caused the crankcase threads to deform, leading to oil leaks between crankcase halves or under the cylinders. We installed one straight-through stud and improved retention of the rest.
2) Original pistons with a 6.3:1 compression ratio (left on each photo) were replaced with non-standard forged ones (right) producing a compression ratio of 9:1. With the new pistons, the engine produced 95 hp at 2800 rpm.
3) Spark plugs and ignition wires were replaced with modern automotive ones.
4) An electric starter has been installed. Unlike the starters on newer Continentals, its configuration is similar to Lycoming engines (see photo below).
5) An alternator has been installed. The configuration was also borrowed from Lycoming, as opposed to Continental O-200/300. The photo shows the base part of the driven starter gear with an integrated driving pulley for the alternator.
When coupled with a McCauley metal prop from a Cessna 150 (69" in diameter, 48" pitch), the engine developed maximum static rpm almost on a par with the 100-horsepower O-200 under the same conditions. One of these engines was installed on a homebuilt aircraft; the videos show an early engine test and its first takeoff.
Continental O-200 in a Cessna 150 experimental modification, uprated to 110 hp, 2017
How do you make a three-seater out of a Cessna 150?
Install the third seat in the back sideways, increase the engine power, and optimise the propeller. The easiest way to uprate an O-200 is to increase the compression ratio. There are both certified and uncertified solutions; the price difference between the former and the latter is approximately threefold.
The certified variant uses the pistons with a 8.5:1 compression ratio (left on the photo, compared to the 7:1 stock piston on the right). The manufacturer declares no increase in output power, but a simple calculation shows an actual power boost of 7%, to 107 hp.
There is also a non-certified solution: one can install pistons with a 9:1 compression ratio (see photo), which is what we did in this enfine. The engine produced 110 hp, which was sufficient to increase the maximum load behind the front seats from 50 to 90 kg without impairing take-off and cruise performance.
With an uprated engine, the stock McCauley prop needs to be re-pitched from 48" to 52"; a still better solution is to install a bigger prop. On this aircraft, we installed a 74" McCauley prop with a 43" pitch from a Taylorcraft. With an extra 50 kg of payload, the modified aircraft retained the original take-off performance and became quite a bit faster in cruise. Alternatively, decreasing the prop pitch by 1 or 2 inches would create a STOL modification. The customer preferred a fast cruise, so we settled on 43 inches.
Continental O-300, uprated to 160 hp, Cessna 172 experimental modification, 2020
Cessna installed Continental O-300 engines on its model 172 until the 1968 model year. These planes are plentiful on the used market, but potential buyers often neglect to look at them, believing the O-300 to be too weak to haul four adult men of today's physique.
A non-certified modification can be implemented on a modest budget. Under our own brand, we built several O-300s uprated to 160 hp similarly to the О-200 above. One of them is shown here.
The stock 76" McCauley prop needs to be re-pitched from 53" to 56".
With these engine and prop modifications, a Cessna 172 airframe shows the same take-off and cruising performance as its newer siblings with a 160-horsepower Lycoming O-320-D.
A similar modification of a Socata Super Rallye (MS.885) boosted its performance to the level of PZL-110 Koliber 160, a 160-horsepower Rallye variant manufactured under license in Poland.
Motorcycle engine conversion
Feeling bored with day-to-day life and hungry for something new, we recently decided to play with engines developed for motorcycles. Two decades ago, we successfully converted the engines from BMW R-1100/1150/1200 motorcycles for use in aeroplanes and autogyros, so this time we came for solutions to the less conservative, dynamically growing motorcycle industry once again.
This 2.2-litre engine used to be manufactured under several brands; currently, only component kits are available on the U.S. market. It attracted our interest by its layout, simplicity of manufacturing, good engineering and low component prices. We modified the cylinder heads to dual ignition and are currently working on a reduction gearbox.
The busy schedule of regular work doesn't leave us much time for this project, so it's progressing at a leisurely pace. We expect to obtain an output of 150 hp at 2400 propeller rpm, a final dry weight of 90 kg and at least 1000 hours of service life between overhauls.
The parts catalogue for this engine fits on two A4 pages. The crankshaft costs a mere tenth of Lycoming crankshaft price. The camshaft assembly with roller tappets would fit in the palm of your hand.
Not a bad engine for weekend flying, huh?
