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Peter Jenkins

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Peter Jenkins last won the day on March 1

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  1. Hi Adrian Thanks for setting out your motor, wing and tail plane settings plus the fact that you need a lot of up elevator trim for level flight. Clearly, for a symmetrical wing section to produce lift it must be at a positive angle of attack. In such a case, the wing produces both a lift force and a moment that tends to pitch the wing up and so we use the tail plane to provide a counter force to this - a down force. With your setup, the wing is at 0 deg so will need to be raised to a positive AoA to generate lift. The tail plane is set at +1 deg so, in relation to the wing, with air flowing over both, and controls at neutral, the TP will produce an upward force tending to push the wing incidence to a negative figure. To counter this, you have had to use "a fair bit of up elevator trim" in order to generate a down force from the whole tail plane. That down force is set for your selected level flight speed to pitch the wing to the incidence that at that airspeed generates sufficient lift to balance the entire weight of the aircraft, and the additional lift needed to counter the down force generated by the TP, in order to maintain level flight. The motor being at 0 Deg will now provide a small element to add to the lift force arrived at by multiplying the thrust force at 0 deg by the sine of the angle of incidence of the wing at level steady flight multiplied by the motor's thrust force. So, at steady level flight at your datum speed, lift force is generated by the wing, a small amount from the motor and a decrement from the tail plane with the resultant net lift force matching the aircraft's weight force. Ordinarily, I would expect to see the wing at a small positive AoA, somewhere between 0.7 and 1.0 deg with the TP at 0 deg. Your starting position is why you have to have so much up elevator trim. If you could increase the wing incidence so that it was in that range rather than at 0 deg, and reduce the TP incidence to 0 deg then you might find that amount of up elevator trim will be different according to: 1) is greatly reduced; 2) requires some down trim or 3) is zero. You can then adjust the TP incidence so that you no longer need any elevator trim to adjust the TP force to be the required value at that speed and weight of the aircraft. On my current F3A machine, I only have wing incidence adjusters so I have to have some elevator trim for my chosen level flight speed. In my case, my motor thrust line is -1 deg (I have a contra fitted), wing initially at 0.7 Deg to eventually 1.25 deg and TP at 0 deg but with some up elevator trim (can't remember how much this is physically since I "zeroed" the servo position by adjusting the threaded clevis. The reason for the increase in wing incidence from the starting value of 0.7 deg was to cater for the requirement to fly a vertical upline hands off to address a pitch to the canopy with the original setup. The pitch to the canopy in vertical flight i.e. no wing lift, meant that there was too much down force from the TP in that state. Counter intuitively, increasing the wing incidence steadily from 0.7 deg to 1.25 deg meant that I needed the fuselage tail to be raised a little bit to reduce the wing incidence back to that required for S&L flight at my datum speed and therefore the TP down force to be reduced a little bit. I continued to increase wing incidence until the required down force needed from the TP was sufficiently reduced to achieve S&L flight on the vertical upline such that the remaining TP down force did not cause a pitch to the canopy on a vertical upline. The slight down thrust from the motor also contributes to this summation of forces and moments. Conversely, a pitch to the undercarriage on the vertical upline would have required an increase in the TP trim force to counter that and that would have required a reduction in the main wing incidence. It all sounds a bit counter intuitive but if you sit down with a piece of paper and draw some force arrows it will become a bit easier to follow. Hope that helps. Lastly, I would not describe the aircraft as being unstable enough for aerobatic flight but rather its stability margin (which is what it's called) is reduced thus enabling aerobatics more easily while the aircraft is still in the stable regime i.e. the CG is still in front of the neutral point. In the full size world, this would equate to stick force per "g" being pulled. In an airliner you might want something like a 50 lb pull force per "g" whereas in an aerobatic aircraft like an Edge that might be around 10 lb per "g" or less - e.g for a 6 g pull the pilot would need to exert a pull force of 60 lb so you might actually want less stick force per "g", say 5 lb in such cases. You could certainly fly the same manoeuvres with a higher stick force per "g" but it would become tiring and require a good deal of strength. For models, this equates to the servo torque that we have available and why we specify such higher torque servos for aerobatics as we want the surfaces to move fast on some manoeuvres e.g. snap rolls. That is also why we move the CG to a more aft position while still retaining positive stability and possibly neutral stability. I have to say, I don't like flying aircraft with neutral stability! Conversely, a CG too far forward makes the aircraft "heavier" to fly as I recounted with stick force per "g" above. Of course, in today's full size world, you can make an unstable aircraft feel stable by using flight control computers that alter the feel of the aircraft as its speed varies. Gyros do the same for us but watch out if the gyro fails with an unstable aircraft!
  2. Yep, same as the Apres Ski stuff. Wait for the end of Feb and go to a ski wear shop and you'll find them flogging them off even cheaper! Good time to get ski jackets and salopettes. But my Dickies onsie does for me!
  3. I use a pair of Zippo hand warmers. If you fill them up completely, they are good for 12 hours. I usually just half fill them and get just over 6 hours out of them. One of each hand in a trouser pocket. I highly recommend them. You do need to replace the catalytic burner from time to time and also buy some Zippo lighter fuel. Worth firing them up 30 mins before you leave the house to get them nice and warm.
  4. I seem to remember you are East Anglia based. So am I. I managed to make the trip to the AGM as a day trip. I would also observe that only a few clubs in East Anglia sent reps to the Esst Anglia Area meetings that were held in the Bury St Edmunds area. The latest East Anglia Area AGM was on Zoom but only a few clubs attended. The Area meetings are open to all club members to attend but there will only be one vote per club. I only ever have seen one or two club members attend in the 6 years I used to be involved. I suspect your wish for one member one vote would be met with the same sort of response as we see from clubs. So I suspect it will be the same people who will step forward to do the hard graft and there will be no difference in outcomes. Just look at what happens in Clubs.
  5. My goodness, has it taken you all this time to realise that? Why do you think there is a specific comment in Article 16 that states that a single rotor machine can be flown above 400 ft provided its AUW does not exceed 7.5 kg but if you have more than 1 rotor you are limited to 400 ft?
  6. Well Matty, looks like the BMFA are ahead of the game and that your pearls of wisdom aren't quite as shiny as you thought. Surprising really!
  7. You forget that there are a lot of people who have donated to support the National Centre, some very generously. This money is outside that from normal subs and is used to support the Centre while it gets going and to invest in providing improved facilities. As such, your argument is wrong in arguing that you would prefer the money rather than having the existing leasing arrangement. The money does not belong to members for futile campaigns against central government which is how you would prefer it used. You are quite right to say you are entitled to express your views. So am I. I have spent several years contributing to the BMFA both at Council, Area and Club level so I feel that those who keep urging the BMFA to do this or that but never offer to help are actually working against the best interests of the body of people who are the BMFA. I'm all for having great ideas but the real issue is having those ideas put into practice. If you aren't prepared to, or just don't have the time to, devote the time to dealing with major problems then carping from the sidelines does not reflect well on one. This is particularly an issue when the facts being used to pursue a particular view are some way off reflecting the real situation.
  8. So, Matty, what do you know? If you are so clever, how come you never offered your expertise to the BMFA at the time but chose to snipe from the sidelines. Just as you are doing now.
  9. Hi Konanige Are you still flying model aircraft? It's gone very quiet.
  10. I suggest Bas that you get your friend to come in and sort out the problem and then write down what you need to do to get the actions you want. I suspect that the additional programme he may have installed is a virus protection service but that doesn't alter how Windows works. In my case, I upgraded from W10 to W11 and that did not cause any problems with how I access photos. I store all my photos in the Pictures folder and then classify them by year. I also take photos with my smart phone and those I download to my computer via an on-line storage system called Dropbox. No one other than those I give permission to access a specific directory can see any of my other photos. It rather sounds like you don't fully understand how you set up folders and use the file manager to access your files. It might be helpful to get your friend to take you through that process and write it all down and use screen shots (he'll know what they are) to help you to remember how to do this stuff. Posting on here is clearly not solving your problem as you would like.
  11. Which altitude rule was that? It is quite extraordinary to see such rubbish written after all the efforts of the BMFA that has led the way for not only UK model flyers but also those on the European Mainland. Incidentally, who is "the BMFA"? There are 3 paid staff who do this type of work. The rest of the BMFA committee members are all volunteers who give their time for free. What do you do to contribute to this effort? You are in a very small minority of people who will gripe about anything given the slightest chance. Can I ask if when you were first asked by the BMFA: Did you write to your MP? Did you respond to the CAA's information gathering request? Did you go and see the Secretary of State to explain why you were seeking a way to carry on as before given the need for the Government to control the use of multi-rotor drones? For you to now write such an utter distortion of the truth is beyond belief. If you don't like what the BMFA has done then you are in a very small minority of malcontents. Perhaps it's time you took up another hobby and spared us this continuous whining when for the sake of a £10 "tax" we can continue to fly as we have always done. The next challenge is clearly going to be beyond you so you can take it that the rest of us will take up the banner to try and prevent a blanket ban of being able to fly out of the field at the back of your house. It is already clear that the CAA is thinking of using "notified" model flying sites to be exempt from RID.
  12. 10 years ago, for aircraft below 7 kg excluding fuel (but including batteries) the height limit was - must remain in unaided visibility. Today, for aircraft below 7.5 kg AUW the height limit is - must remain in unaided visibility. OK, yoy also have to be a member of one of 4 institutions mentioned in Article 16. I'm struggling to see the point you are trying to make as the vast majority of model aircraft fall into the under 7.5 kg weight limit. OK, above 7.5 kg you need an exemption but you can apply for that and you are not limited to 1,500 ft - can't think of many reasons why you would want to go higher although large thermsl soarers might wish to do that.
  13. I run mine for 30 mins - happens to be how long it takes to drive to the patch. The packs nearest to the heat outlet are warmer than the others so I use them last. They feel about as warm as when they have been used on a normal temp day - nothing like the pack temp when flown on a hot day though. I fly the same schedule (FAI P aerobatic schedule that takes about 7.5 mins from take off to landing) on almost every flight but may sometimes repeat a manoeuvre. I have telemetry that shows remaining pack capacity so make the decision based on that. Recharging shows the consumption to be between 3,000 and 3,300 mAh out of a 4,800 mAh pack.
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