Levanter
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Posts posted by Levanter
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I do a lot of flying for work but as a passenger. I like to observe things and this is what I find.
At the end of the cruise all the aircraft pitch down and reduce thrust to keep within Vne. The pitch down is clearly a function of the elevators.Most aircraft maintain a pitch down for most of the descent with the engines on idle. Air brakes extended if the pitch down is steep to keep within Vne
At the end of the descent the slats and flaps are extended (amount depending) and the aircraft pitches up and engine thrust increased as the aircraft goes on the back of the drag curve.
Gear down and sometimes a bit more thrust.
I have not experienced / noticed significant changes in pitch angle at the late stages of flight except on the Canadair Regional Jets and Turboprops. I do regularly experience big changes in thrust setting and the sink rate is instantly reduced (lift quadruples with doubling of speed) without changes in trim. The aircraft keeps the trim into ground effect and dropping the thrust reduces the flare until touchdown.
In the Canadair series the aircraft seem to fly right down to the deck at a constant pitch down angle only to pull into a flare just before touchdown (hopefully). Same with the tuboprops which have massive prop breaking.Last week I was on a 20 minute flight from Mallorca to Menorca and the pilot made a very steep approach only settling into a nose up attitude at low height. It was quite disconcerting.
Different aircraft are clearly flown on different flight profiles but I did find Rob Ashley's explanations surprising and turned my understanding completely on its head.
Levanter -
Posted by Peter Jenkins on 16/07/2019 23:53:09:Posted by Sam Longley on 16/07/2019 18:50:43:Posted by Levanter on 25/01/2019 07:38:08:
Taken to extreme and the windspeed is greater than the airspeed and the aircraft can appear to stand still or even go backwards! But we all know that is "impossible" in aerodynamic terms zo we readily accept the concept of a headwind. . It also explains the common and infamous stall on the downwind turn.
I suppose it would be too much of a thread drift to ask for you to elucidate a bit more on that one
The infamous stall on the downwind leg is caused by pilots thinking that a high downwind ground speed can be reduced by reducing airspeed! The result, is the infamous stall on the downwind leg.
It is quire surprising how many experienced pilots, and even an examiner on one occasion, do not understand the vital difference between air speed and ground speed.
An earlier comment by Simon Cragg falls into that category.
Where things do get confused is when you are descending through a wind gradient (that is wind speed reducing as you approach the ground - exactly like the boundary layer on the wing). In this case, you need to increase your approach speed when landing otherwise as you descend your airspeed will drop away as the speed of the block of air reduces. That is unless you have a very light foamy that immediately reacts to the change in airspeed.
Aerodynamics is not something most model pilots have studied. Where they have it tends to be at a very basic level. Some of us who post on here actually have studied aerodynamics to degree level, have done flight test courses and flew full size power and gliders. It's up to you if you wish to ignore the advice but don't complain when you end up with a broken aeroplane because you ignored the advice.
Hi Sam
Peter has answered your question for me and almost certainly made a better job of it too.
Thanks PeterLevanter
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HI Bill
Certainly a leading edge can be made any size. For me it is just easier to handle and fair in. I make the first strip just wide enough and bevel to match the top and bottom of the rib with a razor plane, protecting the ribs with masking tape.
The second piece is again cut just wide enough and then a few swipes with a razor plane again gets the profile very close. Finished off finally by sanding.
I don't think it is necessarily any stronger but for me, me better to get a good profile.
Other's may find other methods better / easierLevanter
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I built one of those in my teens and I doubt I had the faintest idea what a CoG was for. I think it had a lifting tailplane and maybe it tolerated a CoG quite well aft.
I tested it in long grass just in case but remember it flew very well just floating around. I certainly can't remember adding any more weight but it was a long time ago.
Levanter -
Bill
Reading your post I think you probably mean LE (Leading edge).
I like the two layer / strip system that Peter Miller uses a lot.
I don't like the BIrd's Beak because it creates a weak spot in the rib and if there is a knock on the leading edge it tends to cause a split. This method uses square section stock which is quite easy to fit and requires minimum sanding but I still don't use it.Levanter
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That's a good looking boat Percy and some interesting projects in the pipeline.
Have you been over to the Model Boats forum. It runs at a snails pace compared to this one but lots of useful knowledge to tap into.
Ray Wood has initiated a mini mass build" with HMS Cossack. A famous destroyer with the model designed by Vic Smeed. I am not really into warships but as it will be something completely different for me I am going to give it a go. There are four of us so far.
Levanter -
Den
I have built a number of floats and just use my favourite aliphatic glue which is water resistant when fully cured.
As Percy says, covering with glass cloth is a good thing to do and I cover the float completely using epoxy. This gives a tough and totally waterproof coating. Some people can't use epoxy for allergy reasons or prefer other products but the results are more or less the same.
I am planning a build of a Bombardier CL-415 water bomber and I am going to glass the whole fuselage with epoxy and then paint.I build models boats and have an RC racing yacht. Water has a habit of finding its way in somehow so it is important to thoroughly drain and dry the interior otherwise it won't necessarily just be the glue that fails.
Levanter -
Posted by Martin Harris on 06/07/2019 13:20:49:Posted by Levanter on 06/07/2019 12:04:44:
On the "motoway" going into town (Palma) there is a shunt a day at the moment often as not with a holiday makers hire car in the sandwich.
Cash for crash scam targeting hire cars?
Risky scam Martin seeing all that bent metal.
The other thing I find curious here is that only the police and the Guardia Civil have flashing blue lights. The ambulances (which are mainly run through private clinics) and fire service only have flashing orange that doesn't show up anything like as well. Equal status to a digger, crane, oversized load etc. Must be a macho thing but I am sure it costs lives.
Levanter -
Tailgating is taken to an art form in Spain. You get blocks of cars that look like centipedes going down the road.
On the "motoway" going into town (Palma) there is a shunt a day at the moment often as not with a holiday makers hire car in the sandwich.
Last week two in one day and one of them was just four cars in front of me. You have to work hard to keep a safe space because anything greater than a car's length and someone fills it. I haven't worked out the maths but theoretically you could go backwards
I drive an Audi and don't like my indicators that have a mind of their own.Levanter
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I have seen this elsewhere but the first time I saw it was in Turkey where there was a 20 second countdown to the green light. So many people were killing themselves and other jumping the lights and I believe it had some use.
Side effect though was that every traffic light became a Formula 1 start with everyone revving to go.
Don't start me on driving instructors. They catch them early here. (Spain)
Levanter
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I have an MDS something or other in a second hand plane that I bought on a whim.
After hearing so much about the engines I was quite shocked when after a quick prime and one flick, it burst into life and ran like the proverbial sewing machine. It's a keeper and I quite like the look of the double taper on the head and cylinder.
Looks like I might have been lucky.
Levanter -
Driving in Spain can be taxing at times but it does however prepare you a bit for driving in Italy. The most anarchic country I have driven in has to be Greece.
Interesting thing about Spain is there is virtually no road rage. The Spanish are blissfully unaware of the dangerous goings on. If you resort to a the horn you just get a bemused look and presumably they put you straight down as a foreigner.
Horn though, if you are a micro-second late getting away at the traffic lights, prepare to be deafened.
(oops I forgot Turkey)Levanter
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Lovely model Les
Must kickstart my build to get it finished. Mine has an inverted Saito.
Levanter -
Posted by Percy Verance on 29/06/2019 07:39:43:
Hi Alan
None of us flying in November? I'm out flying all through the Winter if the weather plays ball.....
Hi Percy
I think the comment relates to your point where you said you might be boating from November
Providing of course you are not iced over!
Levanter
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John
It is definitely negative incidence. I have built Richard Harris's Atom Special where it is explained in a number of build blogs. I think you will find that it is the spinning disc that has the positive incidence to create the lift and not the individual blade's relationship with the hub.
Opposite to helicopters where the rotor is driven rather than impelled. 3D helicopters can vary the pitch either way.
I am sure Richard will be back to explain much better than I.
Levanter -
Very nice Martin
Sorely tempted to have a go myself. Do keep us posted.
Levanter -
Been working in Greece this week. Won't say anything about the weather
First day having lunch and there was a copy of RCME on the table left by some kind person. The issue with Peter Miller's L'il Cub and with the plan inside. Rapidly gifted by the staff who saw I was some kind of aero-nut.
Some reading matter for the evenings and a new build to add to my list.
Happy chappy.
Levanter -
Be prepared
This chap was.
Agree with Don on the water rudder(s)Levanter
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David
All of the above.If you have been pulling gliders you should have more than enough grunt to pull the floats.
The only thing I might add concerns longitudinal directional stability. Many floatplanes both full size and models have a vestigial fin under the existing fin to give a bit more area aft of the floats. This is because the floats sit well forward to prevent nose-overs (well that's the idea)
Levanter -
Posted by Doc Marten on 08/06/2019 16:08:08:Posted by john stones 1 on 08/06/2019 14:53:44:Posted by Doc Marten on 08/06/2019 14:36:23:Posted by john stones 1 on 08/06/2019 13:01:39:
Roll on the day the BMFA puts a final update out, and these threads become a thing of the past.
You could always scroll past them.......
I could scroll past them, but I would miss calls from the BMFA to reply in support of them, I often find it here when I haven't checked emails for a while. Plus how would I know the content of the thread, without looking ?
Any other advice for me ?
Plenty.
Here's some more; Replying to every post isn't compulsory after reading it, especially if it's the same as you've said on every other associated topic in another attempt at getting it closed because it irritates you.
I just knew you couldn't resist.Edited By Doc Marten on 08/06/2019 16:27:25
Did you not notice that I didn't reply to your latest "vigilante" prod.
The point of this thread is to wish the BMFA luck and as far as I can see they are going to need it based on certain contributions.Levanter
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Posted by Doc Marten on 06/06/2019 17:33:33:
Levanter, what would be your suggestion?
Not being a vigilante.
Levanter -
Now we are advocating becoming vigilantes.
Are you going to decide that they are breaking the law, get it wrong and then face a charge of criminal damage?
Levanter -
Posted by Martin Harris on 06/06/2019 13:44:31:Posted by Doc Marten on 06/06/2019 12:26:19:
Still willing to play along and show what a decent bunch of chaps we are?
Not panning out so well is it!
While you may be right to gloat at your dire predictions seeming to come true, what's not right is to abandon the fight ad even worse, advocate non compliance.
Although the latest news is not good, the BMFA have a great track record of negotiation with the CAA and we need to show that we are responsible operators for both negotiating with them and the government in order to support any case for selective exemptions, "real" user pays or block registration. I'm sure they have not simply given up in the face of this rebuttal - give them support and don't undermine them.
Anyway, I'm off flying this afternoon while I still can!
Edited By Martin Harris on 06/06/2019 13:45:52
I don't know if it has occurred to those who advocate non-compliance, that they are more likely to damage their own cause than help it. As David Ashby said in the other thread of (of which this is fast becoming an echo) The majority will comply with what ever is needed in order to continue to enjoy their hobby. Some will drop out and that is their choice too. The minority who choose to be militant will not get the traction to make a difference and will be joining the rogue element that will get no sympathy from the general public. I can see the headlines already.If ever there was a case for becoming a member of the BMFA or equivalent organization, now is the time and channel the effort into those who are most likely to be able to make the difference as well following their recommendation to continue to lobby MPs.
Great to see lot's of >250g building and enjoying going on in other threads.
Maturity and level heads needed more than ever I think.
Levanter -
Don't wait for them to call. Call them and say you will not accept being held to cancellation deadlines. Note time of attempted calls if you don't get through.
Stay reasonable like it seems you are. Make contemporary notes in case you end up having to unscramble everything.
Good luck
Levanter
Electric Cars.
in Chit-chat
Posted
It's interesting to hear that the government has announced a clamp down on e-scooters, seems contrary to the perks and encouragement given to e-bike users. Mixed messages from the government as to their commitment to green transport ?
Edited By Doc Marten on 22/07/2019 13:06:43
Same here in Spain but unconnected with any green transport. Some of them are now quite fast, completely silent and causing big problems on the pavements and promenades with accidents.
I don't have very good use of my legs but I can't help wondering if the some of the kids will loose the ability to walk properly because they go everywhere on their scooters even short distances. It's a bit like seeing very large toddlers in pushchairs.
Levanter