General Safety....

[JohnnyG]

I've worked in and with the RAF for over 20 years. I've been around aircraft since I was about 6. Everywhere we go we see posters about Flight Safety. It's drummed into everybody from the moment you step through the door. Even the cooks have to learn how bad food can effect the Pilot and therefore the flight. As I see it model helicopters are no different than the real thing. In fact they are probably more dangerous. How often does a model crash compared to the real thing? There is the added problem of radio failure plus exactly the same mechanical failures and pilot errors. Full size pilots are carefully selected. They build up slowly through each level of training and they are checked continuously before they are let loose. A rare condition for a model pilot.
Full sized heli's go through many hours of servicing before they are allowed to fly. Even if there is nothing to fix. It is checked and double checked and if a system is part of the flying controls, checked for a third time.
Whats the difference between a model and full sized Heli? The size, the power and the fact that nodody is sat in it.

I've noticed that the safety notices in the manuels read more like get out clauses rather than genuine warnings.They are more likely to be ignored rather than be taken seriously. For the complete novice to buy one of these "toys" and then attempt to fly it based on these is frightening. Perhaps they should all come with safety hand books explaining some of the risks. Give some examples of just what can happen. I had a freind who's new car was damaged by a model Heli crashing into it. It cost a fortune to have fixed. How lucky it wasn't a person? I've had my knuckles wrapped by the blades and I can asure anybody I don't fancy doing it again!

I'll admit to dragging my model straight out of the box and taking it out to fly as soon as possible. I'd suspect most people do, promising to set it up later. The risks are just not spelled out clearly enough. Perhaps the moderators can produce a comprehensive safety manuel and publish it here as a Pdf or word document? Its stupid little things like how hot batteries get whilst flying that is'nt mentioned. Maybe some facts and figure on blade tip speeds. Just how fast are those thing travelling? Whats the rpm on a model engine? Start to play with the sums and it gets frightening. For example a car engine at 30,000 rpm (about 60mph) is going around at 500 times a second and most of us sit behind that every day!! What if something breaks?

Get my point ?

[tecmic]

Hi Johnny,

It's got to be your RAF training because It's rare that one sees such an informative posting on safety in this sport. Any serious 'enthusiast' usually appreciates the dangers but, to become an enthusiast they've probably been in it for several years. It's the beginners that are most vulnerable which is why I always recommend they join a club BEFORE spending any money or attempting to fly a heli.

It is strange that, in a country so tied up with safety (speed cameras, road humps, yellow hardhats, etc.) that there is no regulatory control over r/c model aircraft, especially helis. Even a Raptor 30 is more than capable of inflicting serious damage or fatality in an extreme case yet a complete r/c aviation novice can buy, build, fly one in their garden if so inclined.

I'm 2.5 years into the sport and have made one serious mistake so far! Starting my Raptor 30 after some maintenance (left the throttle linkage off) it revved to maximum!!! Fortunately, I was holding the head with my left hand but it was a struggle and burned out the clutch. If it had been a '60' or bigger, the story would be different!

Er? what car have you got then, that revs to 30k? a formula one, maybe?

btw, calculated that the blade tips on the Rappy are doing around 250mph

Mike.

[JohnnyG]

tecmic

you are absolutely correct...me and my maths again. I should have said 3,000 = 60mph and 50 times a second ...sorry did'nt think about what I was writting.
Either way thats a piston firering and the valves opening and closing 200 times a second on a four cylinder engine? Frightens me ...

Figure this one. The Sea King operates at a rotor speed of 235 rpm. The rotor diameter is about 52-56ft. The tip speed is aproaching the speed of sound.

[tecmic]

Hi,

That is amazing! probably why the Seaking vibrates so much? I've flown on the S61 service to the Isle Of Scilly, several times, wonderful

Seaking's a 5 blade head, isn't it? must produce tremendous lift? I had no idea that any heli had a headspeed that slow! but then I'm not very knowledgeable on fullsize. I was told a while back that the standard Jetranger produces about 6 tons of lift!

Mike.

[JohnnyG]

tecmic

Thanks for the interest. I checked out your website. I just love those scale models...Maybe one day..I've been making models most of my life and spent many hours patching up the real things.

Yep the Sea King is 5 bladed. The tail rotor can either be 5 composite blades or 6 metal.

Want some more facts and figures? The blades are 26ft long and weigh in at 200lbs or so. All up weight fully loaded for a Mk3 is about 19,000lb thats over 8.6 metric tonnes.
The blades, rotorhead, main gearbox and engines weight around 3.5 tons which is why they roll over rather than float and hence the fitting of emergency floatation bags on the sponsons.

The main rotorhead is held on by two pairs of wedges, unlike a Wessex which had a single nut. It's known as the "Jesus Nut" for the obvious reason. It's tightened though to 3,500 lbft with a hydraulic wrench.

Sorry if I've bored you .....

[tecmic]

Hey! you'll find it very difficult to bore me with anything aviation!!!

So where's the CofG on a Seaking? must be over half way up the mainshaft!

Thanks, Mike.

[JohnnyG]

tecmic

Lol . I think we ae getting a bit side tracked here. Never mind.

I'm no expert on the C of G but with all the fuel being under the floor it would probably pull it down to what we call the water line. This is a line which runs along the floor level. Supposedly the "water line" at which the Sea King would float. The Fore/Aft C of G is between the two main frames that the main gearbox is attached and will move depending on the loading of the Heli. hence the need for trim. If everybody sits in the back of the cabin the CofG will obviously move backwards.

[hawkman]

Hi JohnnyG, I am just about to undergo a career change. I have been working on fixed wing piston engined (BN2B Islander) for two years and eight months....previous career as a plumber!!!

I am about to start work for British International who operate S61's on contract for the Forces here in the Falklands. I will be working as a fitter.....and am completely 'green'....I am a nervous but thrilled to bits to get such an opportunity...its been a dream job since schooldays.

I have always had a deep interest in Helis since the Falklands War, the Chinook is my favorite by far...what a machine!!!

The Argentines had a mixture of helis, Bell Hueys, pumas, augusta 109's and chinooks....along with Bell 212's (I think) The Task Force helis made things happen without a doubt....the seakings/commandos certainly did sterling work with moving field guns etc....the faithfull wessex seemed to be everywhere at once...and the lone 'survivor' Bravo November...the Chinook...must have been pushed to its limits...more than once.

I know I have pushed off subject Helis are still a regular feature of life here....I live in a part of town which gets overflown by Search and Rescue....usually about 3am...I get woken up by the noise and the searchlight...obviously scanning for hazards. More often than not the Heli has been far out to sea...in a storm...to pick up some poor wretch thats been badly injured on a fishing trawler.
Last year, my Brother and His wife...plus premature and seriously ill son got flown out by heli to the Military Base....for onward medivac to Uruguay (everything went well)..the outcome could have been very different.

So....I owe my freedom to the Task Force...without its helis it might have turned out differently.
My little Nephew might not have survived without the assistance of 78 SQN.

Its Guys like you who keep these amazing machines flying, I only hope to follow in your footsteps

Rob