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John Roberts 9

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Everything posted by John Roberts 9

  1. Has anyone returned their low thrust FMS units to George at 4-Max for testing? He seems to generally have a good reputation in the model flying community and I feel certain that he would want to assist in identifying the problem especially if there is a 'rogue' batch of dodgy or mislabelled FMS units in circulation. I know this won't be of any use to those who purchased direct from Banggood etc. but certainly worth a try for those who bought from 4-Max
  2. The problem certainly sound like a low thrust issue. Although my model is a Gnat it flies well and doesn't need an especially energetic launch to get it away easily. Full throttle and a firm 'push' and it is away with a nice, gentle, controlled climb out. With a 2150 3S Opti-Power LIPO (35C continuous rating) installed the model weighs 615 grams and, using the 'kitchen scale' test produces around 580 grams of thrust. Fan and ESC both came from 4-Max. I also enlarged the 'cheat hole' by about 20% (pretty much as big as it could go) to help the fan 'breathe'. One final thought occurs to me...……...have you 'trained' the ESC to recognise the correct full throttle point? If not then you might be a long way short of full power even with the Rx stick pushed fully forward
  3. I also had a successful maiden with mine a couple of days back. Initially the model displayed pronounced 'Jeremy Corbynism' (leaning strongly to the left!) but a few correcting trim clicks soon resolved that issue. I have left the aileron deflection at the recommended 3mm with plenty of expo (45% on Spektrum) which keeps the changes of direction smooth, flowing and twitch free. As for elevator I settled on 8mm up and 6mm down with 30% expo. Model glides nicely making landing a breeze. Thanks to my friend and clubmate Richard for the photos.
  4. Finally finished my Folland Gnat. Took me rather longer to build than I expected but, on the other hand, I haven't had much else to do over the last few weeks! Applying the covering was a bit of a fiddle but it doesn't look too bad as long as you don't look closely! Scottish lockdown rules have just been relaxed so I hope to start flying again tomorrow but I shall give my rusty thumbs some exercise on my trusty Wot4 before trying to maiden the Gnat. Edited By John Roberts 9 on 28/05/2020 17:18:27 Edited By John Roberts 9 on 28/05/2020 17:45:49
  5. Hi Lucas, Great repair job. What happened on 23/5 is now just a bad dream!
  6. Awww Lucas, what a shame. I think we all share your pain! After a crash my first thoughts are to chuck the remains in the bin but I know to resist that urge because a couple of days later I always find myself figuring out how best to execute a repair. With your building skills it will soon be back in the air. By the sounds of it the main learning point from all this is that the Gnat needs more elevator movement than the recommended 6mm? My build is close to completion and, with a relaxation in Scotlands lockdown rules now imminent, my maiden flight isn't far off (hopefully!). All the best with your repair.
  7. Hi Martin, Thanks for the recommendation. I have a bottle of canopy glue in my stock and whilst I have found that it works well in some situations it can also be a bit messy, especially where the canopy isn't very rigid and/or where the fuselage has compound curves (like the gnat). Could be that I am just ham-fisted of course! Just a few minutes ago I was looking at a piece of depron and wondering if I could use it to make a base for the canopy which would stiffen the whole thing up. Then again I am probably over-thinking and over-complicating.
  8. Hi Lucas, My own Gnat is now getting close to canopy fitting time and so I am particularly interested to see how you get on with yours. From your photo above it looks as though you intend to glue/fix the canopy directly onto the fuselage? I was thinking about doing the same thing but I am not sure how neatly I can do it (and I am fussy about these things!). I am pondering on the idea of making a thin balsa (or foam) 'baseplate' to fit inside the canopy to give it a bit more rigidity. I think I will hold off doing anything and wait to see how you get on! Good luck ! John
  9. Hi Lucas, I am enjoying your build blog, thanks for taking the time to post it My Gnat is a few steps behind yours. Next step is to attach the nose block and start sanding. Keep up the good work! John
  10. @Wilco Wingco Mine is set at 80mm and has now had hundreds of flights without incident so I would say it makes a safe & reliable starting point. The model does seems very tolerant of a wide range of CoG points and I have flown mine with it set as far back as 90mm (experimenting with prop hanging!) and as far forward as 70 mm (using an oversize battery) and, frankly, it didn't make a whole heap of difference. My advice is go for 80 or just a tad less and all should be well. I hope your grandson enjoys it because for such and cheerful foamy it is great fun and super value for money.
  11. Hello and thank you for the replies. One of the reasons I decided to ask here for suggestions was because my own online searches for hotliners seemed to produce very little of interest. This seems to rather bear out the general feeling expressed above that hotliners are currently out of fashion. One of my clubmates has a Staufenbiel Hawk 3 which is a bit of a missile and, whilst that appealed, it no longer seems to be available. That said Horizon Hobby are still listing a 'Staufenbiel Cheetah R 1750mm' which looks similar and could possibly fit the bill. Anyone had experience of this model? It struck me that the RR version using 3s batteries would probably just be reasonably quick rather than genuinely fast. Perhaps the ARF version with a different motor and 4s batteries would be a better way to go? My "sprightly warmliners" are a 2 metre Multiplex Funray (circa 750 watts and weighing just under 2Kg) and an AeroNaut Pepper, as built by David Ashby and featured in the April 2019 edition of RCM&E, (1.2M, 0.8Kg and around 450 watts). Both, especially the Pepper, are reasonably quick but, for some inexplicable reason, I would like to push the boundaries further. My wife thinks (probably correctly) that I am regressing into a second adolescence! Many thanks once again for the responses so far.
  12. I already have a few electric gliders that range from sedate through to reasonably sprightly warmliner but I am beginning to feel the need for a genuine hotliner and would welcome suggestions & recommendations please. My requirements are for something up to about 2M wingspan, suitable for flat field flying and up to about 5-600 quid including motor, esc & servos but these, for the most part, are pretty loose criteria and I am happy to consider things outside these boundaries. I know others have asked similar questions in the past but the most recent thread was about 5 years back and so likely to be out of date now. Thanks in advance.
  13. Due to the very narrow fuselage I have opted to use a Deluxe Materials product called 'Liquid Gravity'. This makes it easy to drill a small access hole into the top of each compartment and slowly add enough weight until I get perfect balance. Add a few drops of cyano, plug the hole(s) and top it off with a small patch of tissue. Job done! In truth, simple lead shot would probably work just as well and be cheaper too but Liquid Gravity offers a very convenient solution.
  14. Thanks everyone for the interesting replies. Although I have flown R/C powered models for quite a few years this is my first real foray into free flight. Although I expected to have to add a bit of lead to the nose (perhaps 5g), what surprises me is just how much is going to be needed. 75g will increase the weight of the Caprice by 60%! My plan now is to open up the 2 forwardmost compartments in the nose and add the necessary weight. These compartments are pretty slim so I was thinking of pouring in a 'slurry' mix of lead shot and epoxy...….or is there a better way to do it? Thanks once again.     Edited By John Roberts 9 on 14/07/2019 08:46:12
  15. The wing chord is 16cm and the recommended balance point is 9cm behind the leading edge. That seemed a long way back but I assumed it was required due to the lifting tailplane. The plan does make reference to the 2 compartments in the nose being used to accommodate balance weights so perhaps adding 75g is the expected norm. It looks as though I am going to have to do some surgery!
  16. Hello, I have just completed a KK Caprice for my next door neighbour and my final task was to check the CoG. Putting it on the balance showed it to be surprisingly tail heavy and it will require 75-80 grams of noseweight to get it balance as per the plan. The model only weighs 125g and so another 75g seems like a (relatively) huge amount to have to add. The model is built exactly as per the instructions, using the supplied materials in the kit and is covered in tissue & dope. Has anyone else had a similar experience with this model?
  17. Irrespective of what the EU regulations might say the Baroness was absolutely unambiguous when she said that all unmanned flying objects above 250 grams will be required to have a transponder fitted within the next 3 years. Their plan is to have some kind of super all-seeing air traffic control system that will be able to identify every aircraft, manned & unmanned. The only exception mentioned was the sub 250 grams class although she also left the door open for even that modest cut-off figure to be reduced should further research indicate that tiny drones represent a risk. Edited By John Roberts 9 on 09/07/2019 19:05:25
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