Here is a list of all the postings Megawatt has made in our forums. Click on a thread name to jump to the thread.
|Thread: Future balsa supplies in UK|
Not all of them apparently
|Thread: Flying through covid !|
The rules are designed to be not consistent - I am getting more and more irritated with the press who seem to immediately look for and highlight inconsistencies!
It is not about some things being safe and others not - it is about stopping doing some less important activities (like model flying) so that more important ones (like sending children to school) can continue - whilst keeping the infection rate to a level which can be dealt with by the hospitals.
|Thread: New limit on groups in England from Monday?|
Ok so if there are 7 flyers at the field all social distancing by 2m - is this an illegal gathering of more than 6 or is it 7 legal groups of 1? If 2m is not enough what is? There will certainly be several groups of less than 6 on the golf course!
Assuming the model has ailerons all of the above is true if, however, you are relying on the rudder then dihedral is essential for the model to roll.
|Thread: CAP1915 UK Drone Corridors - Future impact on model flying?|
Hmm - as I understand it a NOTAM (NOtice To AirMan) is just that - a notice. It does not in itself create a danger or prohibited area or amend the classification of the airspace. It just informs the pilot of an activity so that he can take it into account. Of course a NOTAM can be used to notify the existence of a danger area which has been created for a particular reason.
|Thread: The Gov't, CAA, BMFA & UAV legislation thread|
Might be worth mentioning that as the previous operator ID exemption has now been revoked we presumably need to print out the new one to put on the club wall / carry with us.
|Thread: ARTF tail feathers - what glue do you use|
Cant find the report right now but I believe you are right - there were other factors too from memory.
Most ARTF instructions say you should use epoxy to fix the tailplane and fin to the fuselage - having removed the film to allow a wood to wood joint. I can't help but think it would be far easier and less messy to use PVA or aliphatic glue instead as we are constantly told that these glues produce a joint stronger than the surrounding wood. However I am very mindful of the tragic fatal accident some years ago where (I believe) a tailplane came adrift of a model and it was noted in the report that the wrong adhesive had been used. Now if I were ever to be in that horrible position I would at least like to think that the same report would say that the model was constructed in accordance with the manufacturers instructions. Does anyone know why they specify Epoxy (gap filling?) and what glue do you use?
|Thread: Is this yet another scam|
Posted by Alex Ferguson 2 on 17/05/2019 10:20:44:
A year or so ago I had a call from IRD (tax dept) from an Indian. Hmmm??? So I asked for his name and said I'd ring back. I rang IRD and told the girl who answered. She laughed, said it was actually genuine but she'd handle it. Yes, it was genuine and she knew why I was doing what I was doing but you can't be too careful.
If it might be genuine, look it up in the phone book and ring. A number from the caller might not be correct.
And either use a different phone, your mobile perhaps, or dial a known number first to make sure that the call has cleared. The call does not shutdown until they hang up and there have been cases where they play a dial tone until they hear you redial and then pass the line to another scammer.
Edited By Megawatt on 17/05/2019 10:50:35
|Thread: CAA registration consulation|
Has any information been published about the labelling requirements - Could impact severely on scale models
|Thread: New Drone Laws from 30/5/2018|
I think I need to challenge the assumption that this legislation is to clear the airspace above 400' for commercial drone ops. Full size aircraft are subject to a 500' rule and it is quite legitimate for them to descend to that height for whatever reason and remain legal. IMO the 400' limit and 1KM from an airfield is to allow separation from full-size aircraft and ensure that any increase in commercial drone ops remains segregated from manned aircraft. We shall be sharing the 0-400' range with them.
|Thread: A new possible scam|
If you receive an Email like this do not under any circumstance click on any of the links - these may take you to a fake login page set up just to "harvest" your login details. Always enter the URL into your web browser for any login screen. If you have followed a link then you should change your password ASAP.
|Thread: Life Today and Customer "Choice".|
My problem with the Pizza shop is not the scale of choice but the limitations of what you can and cannot do (like no more that 3 toppings on a 9" )
This always makes me thing that they decide what they want to sell rather than me decide what I want to buy.
Your experience also smack a little of misrepresentation - their offer (should you really only want one 7" pizza) is really a One for the Price of Two offer !!
Edited By Megawatt on 19/10/2016 11:53:04
Edited By Megawatt on 19/10/2016 11:53:50
|Thread: A question of bears.....|
Because the N & S Poles relate to the axis on which the Earth spins.
Im interested in how a mirror reverses your face left to right but not top to bottom - how does it know?
Edited By Megawatt on 17/10/2016 09:44:04
Edited By Megawatt on 17/10/2016 09:44:28
|Thread: A question of physics.....|
Ok I'll start the ball rolling
Both will have the same linear speeds but will have to rotate at different RPM to achieve them
Ok One last time (this time I mean it)
Yes the bottom of the wheel is in contact with the belt and is moving back at 150mph relative to the air
No the axle is not stationary it is moving relative to the air at 150mph - and 300mph relative to the belt - it is revolving twice as fast as on a stationary runway remember
The top of the wheel is moving at 300 mph relative to the air and 450 mph relative to the belt
Draw it out if you want to - I did
Once again your man on the treadmill can only derive his thrust from the belt which reacts to his movement such as to keep him there - the 747 has no such constraint.
A final example - not that it will do any good if you do not believe your own eyes watching the mythbusters video - Consider a car, in neutral on a rolling road with the brakes off. The road is moving at 30mph and the car is held stationary by a rope attached to something off the rolling road in front of it. Now then the something it is attached to is a winch which begins to shorten the rope at 5mph - the rolling road compensates by increasing its speed to 35mph. Are you really saying that the car will not be winched off the road!
That really is it for me - I'm off back to lurking.
Edited By Megawatt on 16/10/2016 11:14:44
Well I hope we're all still having fun because that's what this is about. Like Gary this is not about point scoring but the enjoyment of discussing logic and hopefully causing pennies to drop. Having said that I am beginning to suspect that one or two people are having a little fun at our expense so this is my last attempt - forgive the long post but I am going to try to cover it all.
I will assume that conditions are perfect throughout i.e. frictionless bearings, massless wheels and nil wind so as to show the concepts and because the real world effects are small or transitory - if you are unhappy with this approach then there are several youtube videos which deal with the real world issues and demonstrate that they do not affect the outcome - take a look if you can follow the maths.
This question all revolves (pun intended) around wheels - nothing else really.
So lets start with a car on a conveyor with a driven wheel at the rear axle and a free wheel at the front. If the Car starts moving the conveyor matches its speed and the car will not move relative to the air. This is because the car can only get its propulsion from the reaction between the rim of the wheel and the conveyor - if the conveyor moves backward then the car cannot move forward. Please note that the speed the conveyor must move at is the speed of the axle if the car is to remain stationary not the speed of the top of the wheel or the bottom but the axle which as it is rigidly attached to the car is the same speed as the car. Now think of the front free wheel it knows nothing about what is happening at the rear - it simply rotates at whatever rate is necessary for there to be no slip between the wheel and the belt. As I said before that is what wheels do - they are no good for making tea and cannot receive radio one or get the children ready for school but they are brilliant at moving something over a smooth surface with little (or in our example no) resistance.
Now think about our 747. Its propulsion is generated completely independently from the conveyor - the conveyor cannot influence its speed in any way as it is resting on frictionless bearing wheels - the belt could be moving at Mach 0.99 and not be able to influence the speed of the 747 (ignoring any small real world effects due to air disturbance). But its not even moving at Mach 0.99 - only at the same speed as the wheel axle/747. So the 747 accelerates which makes the belt accelerate to the same but opposite speed but the plane still moves through the air and takes off.
Mythbusters actually did a pretty good job of recreating this - if the plane won't move brigade were right I would have expected the plane to maybe move back and forth a little due to errors in speed but it didn't, it smoothly accelerated and took off - in the real world with the wheels rotating at twice the rpm they normally would.
Edited By Megawatt on 16/10/2016 10:05:07
Ok what does the original question not say - it does not say that the conveyor moves in the opposite direction so as to render the plane stationary - because that would be impossible the conveyor has no means to achieve that.
What it says is that it will travel at an equal speed (note this implies that the 747 is moving, speed being distance moved over time) in the opposite direction, So the original question allows for the 747 to be moving in one direction whilst the conveyer moves in the other resulting in the rotation of the wheels at the correct rpm to result in no skidding. I really can't see why this is so difficult to grasp.
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