Peter Miller

Rereading kermode I think he was referring to a slideslip which you would not get in a balanced turn, Mechanics of Flight is virtually the same as Flight without Formulae but has masses of maths in it which I am afraid are way over the top of my head. I also have a superb book called "The Design of the Aeroplane" by Darrol Stinton. It covers everything you ever need to know and more, Most of it is way over my head again but I do pick odd bits out of it plus some interesting annecdotes.. Alasdair reccommended it to me and I bought a copy S/H, cost a fortune.

I have said that I would never argue with Alasdair Sutherland BUT and it is a big BUT, I would argue even less with A.C. Kermode. I have beend doing a little reading and Kermode says. "Aeroplanes in which wings are high and the centre of gravity low may be stable without any dihedral angle. Many high wing monoplanes are examples of this type. The weight being low acts like a pendulum while the aeroplane sideslips, the resistance of the wings to their motion through the air holding them back and thus supporting the pendulum. As might be imagined, this method of obtaining stability tends rather to a rolling motion from side to side." From "Flight without Formulae" Which has been in continuous publication from the 30s right through until at least the 90s.

The BMFA has a reporting system for ARTF faults. I suggest that everyone uses that. They do get on to the manufactures/importers. I know because I reported a major U/C failure on a Baby Boomerang owned by a club member. The retratcs started to rip out on take off. There was not glue holding the retract bearers to the spars. When the owner started to repair it he was able to removed the entire bottom skin without any problem, again, no glue. It hasn't failed since inspite of numerous landings and take offs from grass strips.

I would never argue with Alasdair on the matter of aerodynamics. There are an awful lot of myths and wierd theories that used to go about in the days when aeromodellers were into that sort of thing in a big way. For example, I remember one very strange one. Lift acts verticaly, it has to because it counteracts gravity. Dihedral works because in a bank the low wing presents more area because it is jnow flat while the other wing is at a greater andgle and so presents less projected area. Don't laugh, I remember seeing that in a magazine. I think I may have even believed it for a time.

There used to be a big collectors range of assorted pigs dressed up in various constumes made in resin. I can't remember who made them nor do I know if they are still around but try searching on eBay. IN passing, if my tired old memory serves me correctly the Vickers Varsity used to be called "the Pig" I know that ours on MDA Flight, R.A.F. St Mawgan, was always called the pig. And again talking of pilots. I have just aquired a genuine pilots flying suit from the Battle of Britain Memorial Flight. Even got the pilot's name "Shiney Simmons" and all the badges etc embroidered on it. Only trouble is, I am to fat to wear it.

One of the secrets of strength without excessive weight is this. Spread the load and taper the strength off the further away from the maximum load areas. This was something that I was taught on my Airframe Fitters course in the R.A.F. about 51 years ago A suddent change of section is always a weak point and stress area. For example spars should be thick at the root and thin at the tip.

I think that you will find that the fact that that the high wing model has a centre of lift above the centre of gravity while the low wing model has the centre of lift below the CG has something to do with it. In other words, the pendulum effect as Bob says.

Tony. AS I understand it, stalling speed is governed by the airfoil shape and the angle of attack. Each airfoil has a stalling angle, the angle at which the airflow breaks away from the top surface. Wing loading only comes into it because to support more weight (higher wing loading) at a given speed requires a higher angle of attack. Therefore to maintain level flight with a higher wing loading without increasing the angle of attack the aircraft has to fly faster. Thus a heavier aircraft has a higher stalling speed. I think that I have got that right...well, I know what I meant to say.

I think that probably to origins of the high wing trainer started with the progression from free flight and the early R/C models. The early trainers were basically free flight designs and so were stable. I am not too happy with the suggestion that low wing models are as stable as high wing. I base this staement on the fact that a high wing free flight model only needs about 5 degrees of dihedral while a low wing model needs 10 degrees. I think that these days one good reason for using a high wing model is orientation. It is easier to recognise which way up ahigh wing model is, well, I find that anyway. On the other had high wing models can be just as aerobatic as low wingers. I do feel that tricycle undercarriages are a total waste of time unless one is flying from a bowling green or smooth concrete.

I feel that the very weak undercarriage mountings on ARTFs (and I have seen quite a few in the club) are further proof that the people who engineer ARTFs know nothing about models. I say this because any real, experienced modeller will know that a heavy landing can bend 8SWG piano wire quite easily and that it then takes a vice and heavy hammer to get it back to its original shape. That is an indication of the load imposed. When you add in the factor that the ARTF undercarriages are normally dural with no rearward flexing it is no wonder that they just rip out the pathetic mountings.

Ref: Eric's comment. To expand, the longer the moment arm, the smaller that tailplane can be. The Cub has a long moment arm. If the tailplane is small and the moment arm is short then the CG has to move forward. The cub has a pretty reasonable size of tailplane, I estimate about 15% of the wing area. If the CG is too far back a model will be very sensitive to the elevators and a sudden pitch up could cause a tip stall, this is related to CG location, not moment arm. Unless, of course, Maurice Ashby knows better.

John, You accident was due to trying to turn too low and too slow. I do sympathise, I lost one of my best control line scale models at Old Warden many years ago in the same way, uncontrolled brats running across the circle as I was taking off. Our point is that Maurice Ashby stated that a short coupled model i.e. one with a short moment arm was prone to tip stalling. There is absolutely no reason why a short moment arm would make a model prone to tip stalling that we know of. And anyway, the Piper Cub has a long moment arm, exactly 1.5 chords which is longer than many aircraft. If you look at the picture at the heading of this posting you will see my Culver Dart, not only has it an ultra short moment arm, it has sharply tapered tips going to almost a point. The tip shape could easily generate a tip stall but it doesn't on the model which is most forgiving.

I knew about Kennedy. The Queen Bee was basically a Tiger Moth if my memory serves me correctly. It could be flown by a pilot. Likewise the Fairey Firefly was a modification but we are talking about aircraft that can be flown without a pilot in the cockpit so they both qualify. I believe that some of the Culver Cadets were also modified in the same way and I am sure that there are dozens of others.

Tom, see my posting above. you could also build a Fairey Firefly.Or even a B-17 but you would have to remove the top from the windscreen back to the radio position. They called them Aphrodite aircraft and one caused the biggest explosion ever seen in this country.

Steve, if you want to put an electric motor in it feel free...just don't tell me about it. Mike No, but I use NACA 0018 in a control line stunter, not a 12% section and control line stunters are flown to much greater precision than any R/C model. I originally got the idea from a full size fighter. Let's see if anyone knows which aircraft that is.

Why do I use a flat bottomed section? Because in the way that I use it it works just like a symmetrical section and is much, much easier to build. If you read the sequence it is built flat on the board until all the sheeting is completed and the capstrips, I never, ever get a warp in one of these wings. The wing is then set at 0 degrees incident measured on the chord line, not the bottom of the wing as so many people do it. As for exposed engine. Even the .32 would be exposed when it is side mounted and then the silencer would have no where to go. I doubt that a Wankle engine would go in the cowling. Wait until you see my next one. 1/6th scale piano hinges essential and opening aluminium side panels. Lots of stringers and a flat bottomed section because it is scale. Still no explanation on that tip stalling question, I wonder why?

I have an ancient henley Solon 75 watt iron which works well as it has a huge bit. It does take time to heat up. I also have a set of irons, a 80 waat and a small one. These came complete with solder, flux and desoldering braid fro ALDI for £5. Keep an eye on the Aldi website because they will be back. Better still register with Aldi to email you each week with their bargains. How about a Power plane for £12? Only used mine once but it was worth every penny. Now I can shape up large hardwood patterns for canopies in nothing flat.

I agree that a good club is the best way to go. We have at least three members in our club who were refugees from other clubs where they just did not get the amount of help/time that they needed. Yes Tony, an electric glider is similar to the sort of model that I was talking about for flying characteristics but it should be one of the larger ones. They cope with breezes a bit better, I suggest an Easy Pigeon, mine has been used to help a couple of learners. I have seen other similar sized models which were not as stable or forgiving for some reason.

The Cap 21 has a SC 32 two stroke. I think you may be getting mixed up with my Fournier RF7 in Simon Delaney's column. They keep saying a .25 for the CAP 21. Well, it would be quite nice with that engine but the .32 is needed for thr sustained knife edge. If you go with the .25 KEEP IT LIGHT. A 30 FS would NOT be very good at all.

I saw her and didn't recognise the plane, just another spamcan but Cessnas are high wing so I am guessing a Piper.

I taught myself to fly long before simulators. The secret is a model that will return to level flight if you take your fingers off the sticks. One that is slow enough to allow one time to think. Any modern trainer that says that it will fly aerobatics is NOT any use for that. I started with a Super Sixty on rudder and throttle and then changed it to Rudder Elevator. I only had a two channel set. Then when I finally got a four channel set I went on to a Tyro Major. So stable that when I forgot to switch on it flew for four miles. A Barnstormer was another good three channel model. I did have one advantage, I came up through control line and free flight as most of us did in those days. This gave one an appreciation of trimming and the effect of controls and how to repair models.

No offense taken. If one takes offense easily one should not go onto forums. With regard to your reply to Jetsome....I know that feeling only too well. The bit that really got me was when I asked for help to mow the grass and no one did and then I was told "You can expect people to disrupt their lives to help you"

I have just learned something new from a kit review! Maurice Asby, in his review of the Piper Cub says "Small, Short coupled models like this can have tip stalling characteristics." I never knew this and could not imagine why the moment arm should affect the tip stalling characteristics. I dived at my Kermode and and Darryl Stinton books on the subject of aerodymanics and could not find a mention of this anywhere. Please could someone explain why the moment arm should affect the tip stall? I know all the other things that can and do cause tip stalling. Also, please tell me what qualifies as short coupled, the Piper Cub has a tail moment of over one and half chords, not what I would consider short coupled.

We are not hostile to people with family commitments, we have members who turn up once a year because of them, They ised to be regulars and so stay members . The problem is that we only fly on Sundays and someone who is on their probationary four visits states that they can't come on Sundays who would be taking up one of our limited spaces we feel that that is unreasonable.

I agree with so much of the above. We have a very small club. Membership is limited because a) we all have allocated frequencies with no duplicates and b) We use various sites and the owners would object to too many cars parked in their farmyards. The advantage is that beginners get much more tuition because ther is no waiting for slots. Apart from one jet we fly average sports aerobatic models and some electric so no one should feel intimidated. We consider ours selves more a group of friends and new members come in on a trial basis of four flying sessions before they or we agree to final acceptance. This may sound elitist but it isn't, One person was refused when he said that he wouldn't be able to come on Sundays because he had to work on Saturdays and had other things to do on Sunday!!! It is important that a small group has a similar attitude because one discordant type can sour the whole thing as was proved a few years ago. I can say that there are NO cliques in this club. WE are on the West Suffolk/Essex border and we do have a couple of vacancies if anyone wants to email me.