Month: May 2019

RC plane engine options

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Remote Control Plane Engine Options

Three main types: petrol engine, electric engine and now a days jet engines. Yes legit actual jet engines. There is also a derivative of the propeller usually electric propeller engine that is a fan instead of a prop that fits in a jet fuselage but they are not real jets.

The petrol engines run on Nitromethanol – I think – and they have a reciprocating piston combustion engine. I asume they are two stroke. They dont have a spark plug, instead they have a ‘glow plug’ which is basically a very small coil of wire at the top of the cylinder. You start a petrol engine by attaching a battery pack via small alligator clamps to the glow plug’s outside protrusion and the body of the engine. That causes the glow plug to glow and then you spin the propeller and if the fuel air mixture is ok then the engine fires and your in business. Because the prop is a danger and tedious to finger flick, you can buy a device that spins the prop for starting – a kind of external hand held starter motor. These little petrol engines actually produce some serious power thrust and NOISE! They are measure in CC or cubic inch in figures like 0.40, 0.60 etc. Air cooled. Apparently according to science these glow engines shouldnt work but they do haha. The start process can be difficult and is similar to starting a petrol / gas powered lawn mower engine. They can fly for a long time.

Then theres electric engines, they have some pros and cons, namely they are less noisy than petrol engines, they can change battery packs and go again quickly they are easy to start and stop, they are not very hard to operate. BUT the batteries will last a few minutes only. And also as petrol burns, the plane gets lighter, but as a battery runs out of juice they electric plane remains at its takeoff weight – unless you have mice onboard trained to throw the battery overboard. lol. In any case both types of plane still require a separate battery system to run the transmitter receiver, and servo controllers.  If you are using a drone style multicopter style config, you may prefer electric engines, because you can make minute and instant power adjustments which is perfect for computer controlled drone stabilisation.

Jets: Jets are relatively new and SO EXCITING!! The best known manufactuerers of RC Jets is Jetcat. There are also a plethora of small bespoke manufacturers and budding designer/builders. So far the state of the art of RC jets is they require a major overhaul every 50 hours. Also they are very innefficient compared to proper sized jets and same power piston engines. I reckon one of the inherent problems of RC jet engines is that their small internal circumference means an outsized boundary layer on the inner surface which will probably clog up the airflow and cause inneficiency. Only way to solve that would be to increae the size of the jet.  We are starting to see some of the larger RC jets being utilised for small personal ultralight aircraft such as the 4 Jetcat jet engines on the Yves Rossi Red Bull wing suite. I believe they are in the order of 200 Newtons thrust each – 20KG of thrust per jet. Not bad. Another crossover success is to power the Cri Cri with two jets or to use a jet or two on a glider.  As time progresses these RC jet engines will likely become more reliable, longer interval between overhaul and cheaper to acquire.

In summary RC planes can use electric petrol and jet engines.

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And just finally I couldnt cover RC plane engines without mentioning Moki radials! Check out the sights and sounds of this sensational engine! Moki engines are amazing because they are true radial engines small enough for use on RC planes. Often RC planes in the past that needed to simulate the appearance of a radial engine, would kind of dress-up to look like a radial. But now that there are real radials, theres no need for that, and they produce some power too!

Actually let me add just one more engine type to the list: Pulse jets! Yes you can get RC plane pulse jet engines. I believe HobbyKing sells a plane that is powered by pulse jet. Pulse jets are extremely extremely extremely extremely loud…But apart from that, and their massive fuel consumption and their tendency to glow red hot, they are nice little engines with no moving parts!

 

Toy planes that actually fly – My take

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Toy planes that actually fly – My take

You can get a pc and a flight sim and thats well and good, but what about IRL toy planes? Plastic static models such as Airfix and Revel brands are pretty great, except you gotta build em and paint em and apply the decals. Then you gotta make sure you dont break them because theyre so fragile. BUT they look great on a desk or suspended from the ceiling by fishing line. But they dont actually fly.

So whats good that flies? I reckon to get started you want a rubber-band powered foam warbird. They have approx a foot wingspan and around a foot long fuselage. They have a rubber band inside the fuselage and when the propeller is wound up, the rubber band takes on potential kinetic energy and bam. You have a power source. Get a Spitfire, a Mitsubishi Zero or a Mustang. They are actually really great. Wind up, throw-launch into the air on a relatively still day and watch the plane ascend gracefully and fly around for up to around a minute. If you go up on a big hillside and launch, you can fly for ages. No joke, these little foam wind-up rubber band powered warbirds are actually a worthwhile thing.

Downsides: Eventually the foam area around the spinner axle, becomes fatigued and under the pressure of the rubber band it caves in and effectively renders the power source useless. You can fix it somehow but its never good as when new.

They break on hard landings and impacting objects such as tree branches. In a suburban environment they can fly over the fence – once you launch you have no control where the plane goes. So the best place to fly is in a big empty park, or in the country side or on a farm. Or a sports oval.

Whats the point? One thing I liked about these type of toy planes that fly is they fly!!! More specifically and perhaps unexpectadly, you get a really good opportunity to kind of learn basic physics and aerodynamics. You throw your Spitfire into the air and it just sails off so gracefully. You kind of get an appreciation for that eliptical wing shape. And weight and balance. Even a kid can start to intuit things like the usefulness of dihedral,  weight in the nose, lift acting through the center of lift of the wing, center of gravity, how the nose lifts and the plane climbs under power, but the nose declines and the plane descends without power etc etc etc. Even as a kid if you dont yet have the terminology to describe this stuff, you can kind of learn it by owning and operating a rubber band powered plane. Further thrust becomes apparent when you cant figure out why the Spitfire stalls out straight after launch and you finally realise you have been mistakenly winding the propeller the wrong direction – reverse thrust.

There you go, there is some insight on rubber band powered warbird toys. Finally, some people like to spend 6 months building a really complex plane out of balsa wood and doped tissue paper and thats great but I recommend just buy a ARF (Almost Ready To Fly) foam model warbird, because A they look great B they fly great and C they are cheap and also they are easy to replace when they get battered over time and that all represents great value in my opinion. Below are some balsa and tissue models Its gonna suck building them, but hey they have some great models there even a Nakajima float plane and a TBF Avenger AND a B17 Flying Fortress, a PBY Catalina, EVEN a Cessna 150! – thats a seriously comprehensive range and the customer reviews look acceptable. Ill probably get the Spitfire and If I do Ill make a vid of the build and of course the plane in flight. Note make sure you’re getting a FLYING model, not a DISPLAY model as they seem to have a few display only kits.

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