For our application these engines should be in used in the fan cooled configuration. You can expect to spend $15,000 or more to reposer with a new 912. The Hirth 3702, 84 HP, and 3703, 100 HP engines are three cylinder inline water cooled engines. While it may be feasible to find a core and overhaul it for use on a new airframe, keep in mind that it will become harder to find parts. That is 15 lbs lighter than a 447 with B box, and 10 more horsepower!
If you are not convinced, I would like to invite you to come fly in mine. However, there is no structural limitation that would prevent the use of a 503, or similar weight or power engine.
However, this engine to date has never been installed on a Challenger. It has incredible torque.
The F33, 447 and Kawasaki all have installation packages available directly from the Aerolite factory. But we have a solution for that. In reality, at 50 hours per year, a 2000+ hour TBO (Time Before Overhaul) really is not a significant benefit to us. It is cost prohibitive to overhaul.
The best application for these engines is single seat Quicksilvers, as well as the Aerolite 103.
The 2702 produces 40 hp at only 5500 rpm while building an impressive torque of 39 ft lbs. It’s only disadvantage compared to a 447, is that it is significantly heavier, around 10 lbs.
The cylinder walls are electrochemically coated with Nikasil. Aerolite is currently working on a factory installation for the F23. To this day, Hirth manufactures many models of two stroke engines for aviation, both manned and unmanned, but they still have no interest in the four stroke market. Hirth has been in the engine manufacturing business since before World War 2. The F33, 447 and Kawasaki all have installation … At any rate, oil injection is not an ‘install it and forget it’ option. The wieght figures are off the internet, so who knows how accurate they really are, but someone put a lot of work into finding these figures, so they are probably correct or close to it. Personally, I do not recommend oil injection.
It appears that the F23 will also be the first of the Hirth line to achieve ATSM certification for Special Light Sport Aircraft. One other option would be a Hirth inline engine. The Rotax 377, 447 and 503 were all made in a non provision version for the non aircraft market, and can be bought for a few hundred dollars. The 2702, 40 HP is perfectly adequate to make this a fun airplane. I will put my money on Hirth engines. The Briggs engine is 22 HP and reportedly the Aerolite will climb at 600 fpm with it. It is also possible to use the 3503 Hirth in this application. However, not long after that the 503 was discontinued, and the 582 remains the only ATSM certified two stroke, at least for now. In many cases the F33 can even make ultralight weight with electric start! Probably the biggest attraction to these engines is the low cost. People who do not understand two stroke engines and tuning, really do not need to with fuel injection. The Rotax 582 65 HP is the only two stroke aviation engine that Rotax currently produces. In the experimental aircraft world we have the freedom to use any engine we would like, no matter how crazy! Rotax 582 95 Includes 20 lbs radiator, etc. From the Quicksilver factory, the 582 is the preferred engine and if ordering an airframe complete with engine, that is the only option. The engine heats up quickly until the thermostat opens quickly and allows cold coolant to rush in which cools the cylinders rapidly and contract until they are smaller than the pistons and a seizure occurs. When considering an engine for the GT500, 65 HP should be the starting point.
While parts will still be available for a few more years, they will eventually dry up. Now we can use whatever ratio will work best for our airframe. Later the E gearbox was introduced, being similar to the C gearbox with the addition of electric start integrated into the gearbox.
Rotax 277 Vs Hirth F33. Currently, Quicksilver is experimenting with the use of the F23 on the Sprint and Sport models. It is very simple installation, less weight, longer TBO, lower fuel burn… it’s just a better engine. (especially on Challengers due to the tall redrive increasing torsional vibration). While there are a few four stroke engines that are being used in our type of aircraft, I really think that a two stroke is much better suited to this application. That simply means that the engine does not have a provision for a gearbox. To tear it down would cost well over $10,000, quite a deterrent to doing an overhaul, so it will probably keep flying like a ticking time bomb. They made engines for the Luftwaffe during the war. The 2702 is fairly heavy for a 40 HP engine, weighing around 10 lbs more than a 447. The main two models of four stroke engines that are popular in our aircraft are the Rotax 912, and the HKS 700. Rotax 912 165 Includes 20 lbs radiator, et, CAM-100 225 Includes 20 lbs radiator, etc. However, when considering all of the options, for a little more money and nearly the same weight you could opt for a 3202 at 55 HP. EFI also eliminates the possibility of carb ice. It increases engine torque and reduces fuel burn. If you would like more power, the 3202 would be an excellent option. Because of these modern design innovations Hirth is able to rate their engines at a 1000-1200 hour TBO. Once mixed it will not separate. I Other engines can use a light weight (and cheapish) wood prop, which gives a lighter total installed weight and affects the aircraft CG less (but it's hard to beat metal for durability), If this is your first visit, be sure to
There are several OEM’s that are currently using the 582 in kit aircraft as well as SLSA aircraft. Secondly, if there is a failure in any engine I sell, I want to know about it, and to be the one to find out what failed and why so we can prevent it in the future. In comparison to the upfront cost of the engine and the cost of maintenance that really is not very significant. So now we can custom tune our propeller RPM to the needs of our airframe and engine to maximize our performance and efficiency. A two stroke engine has an incredible power to weight ratio compared to a four stroke. They use the same bolt pattern on the crankcase and can therefore use the same mount, as well as the same radiator system as a 582.
The TBO is 1000 hours, half of the TBO of a 912, and over three times the TBO of the 582. The 447 engine was discontinued around 2006, and Rotax has committed to providing parts for 10 years. Many people like the option of having a four stroke engine, and so Quicksilver has provided that as an option. Eventually, as the ultralight aircraft industry began to take off they began to make engines for that market, and soon the UAV market as well. In an application that requires a gearbox, the 2702 is fitted with the G50 gearbox. It is also used on the Aerolite 103 to make Part 103. Like all Hirth aviation engines it includes dual electronic ignition. It is a very powerful engine that works very well on many two seat light sport aircraft. In the early 80’s when the ultralight movement was taking off, many people found the the Rotax engines worked well for this new application. However, there is no structural limitation that would prevent the use of a 503, or similar weight or power engine. It is essentially the same weight as a 2702, or Rotax 503. There are also other options on these airframes. The average is around 50 hours per year. Generally we recommend the Powerfin E model three blade prop for this application. Now we have an engine that we spent far less on upfront, was never more than 7 years from a tear down inspection and re-seal, and can be overhauled completely for a fraction of the cost. One of the most common causes of engine failure in two strokes is improper prop loading and carb tuning.
There is an installation available for the Aerolite 103, and one is being developed for a Quicksilver as well. It has been done and an installation package is available. It is also a very economical engine. , The F-33 produces 22 hp (16 kW) at 5200 rpm and 28 hp (21 kW) at 6500 rpm. Standard starting is recoil start. The crankshaft is warranted for 3 years from date of purchase. Because it is built on the same design as the 55 and 65 HP models, it uses many of the same components including the crankshaft. EFI has some wonderful benefits. If reliability is absolutely paramount for you, I would probably recommend carbs, but only if you are willing to really educate yourself on the operation of carbs and two stroke engine tuning. That is with electric start and a lead acid battery. I do not consider the 582 to be as reliable of an engine as the 503. The Hirth 3203, 65 HP, is nearly identical to the 3202, but is ported and tuned differently to make peak horsepower at 6500 RPM rather than 5500. With EFI the engine can be run leaner without compromising safety which results in lower fuel burn and a cleaner engine. , The F-33 was intended to fill the niche previously occupied by the now out-of-production 28 hp (21 kW) Rotax 277.
Another category where the 3203 trumps the 582 is fuel burn. If you fly from low elevation to high elevation or altitudes, EFI has a very significant advantage of precisely leaning the mixture. Secondly, it is much more durable. I could get a 240 lb guy up on a cold day, but it made me very uneasy. It is actually possible to be in the air and flying in a brand new quicksilver for about $11K. However, the cost of the overhaul of the 3002/3003 is much less than half the cost to overhaul a 912. To further complicate things, it uses dual exhaust. Who can afford a $25,000 Lycoming to put on a $15,000 airframe to fly 50 hours per year? They are much less expensive and easier to install and operate than a 912. It will install easily in nearly any application that the 503 was used in, and will out perform it with no weight gain. The years will do more harm to the engine than the wear will. This makes it quieter and more fuel efficient. I am a strong believer that airplanes should use air cooled engines if at all possible. You could use a 582 on this airframe, but you will never get close to these weights, and you will have additional drag. The Hirth 3202, 55 HP engine is a low rpm, high torque engine, making it’s peak power at 5500 RPM. If I were building a GT500 for recreational flying, I would put a 3203 on it. That is not an issue in any of the airframes we sell however, and therefore an air cooled engine is superior in every way for our application. (but really produces the power - that weight is also from the Stratus web site). They mount similar to a 912, will provide more thrust than a 912 and save around 40 lbs of weight. Horsepower is a measurement of torque (the turning force of the crankshaft) multiplied by RPM. The engines that have Denso ignition were originally sled engines. First, we will discuss each engine model, then we will consider each airframe and what is the best match for each.