Here is a list of all the postings Ian Newton has made in our forums. Click on a thread name to jump to the thread.
|Thread: Harrier Jump Jet- The aeromodelling Holy Grail !!!!|
Oh no! That's such a shame. Still at least you have learnt a lot and each step brings you closer to success
Great to see it flying Tony. When are you going to attempt a transition?
Having flown both the Ripmax Transition VTOL and the Hobbyking Canadair CL84 Tilt Wing models I agree that the transition from the level flight to vertical landing is the trickiest as you have to judge where the plane will come to a stable hover. It is vital that you ensure you haven't run your batteries right down prior to landing as the motors need to be able to respond to inputs and provide full thrust while landing! At least with the right strip it should be possible to do a normal fixed wing landing if required. I look forward to seeing the progress Tony makes with this model and hope it is successful.
That's bad news about he crash but the rest is great news! Look forward to the articles. Presumably the Graphene batteries made a difference?
Tony. That certainly is my experience. The nano tech packs that I was using in my edf's and high current draw planes were coming down very warm. The graphenes come down just warm. IR's are around 1 - 2 mOhms per cell. Some have been immeasurable on the icharger I have been using for the measurements. Good luck - I will follow the project with interest and hope to follow in your path when you have led the way. I'm really happy with the 72" Lancaster I have recently finished from your plans so have been looking for something to follow on.
I look forward to hearing if the Graphenes give a noticeable difference. They certainly should be better towards the end of the flight but giving up their power more freely will potentially shorten the flight and they are of course slightly smaller in capacity to start with than your current batteries. What total current are you drawing in the hover?
Tony, that looks awesome! I have recently flown both the Ripmax transition VTOL plane and the HobbyKing CL-415 Canadair which are both interesting to fly and really fancy this Harrier when you have got it sorted. Are you using the Hobbyking Graphene batteries in this model? If not, then I highly recommend them as they will supply the power you require for the ducted fan units better than any other LiPo I have used. I use them in my EDF jets and their performance is excellent with hardly any voltage sag throughout the flight, so their power delivery characteristics are just what you will need. They do 'drop off the cliff' at the end though, so make sure you land with time in hand especially as you will need full power to land vertically
|Thread: 2013 Mass Build - general chat thread|
Just been reading these recent posts. Thought I would contribute my experiences. I have used both silver solarfilm and silver Oracover (profilm) with Spektrum 2.4GHz equipment on several models and there was no noticeable affect even at long distance with the receiver and aerial(s) inboard. Hope this helps.
Chris, quite possibly they do -I've never dismantled mine! - but again (as per the castle creations link that Danny posted) the guidance is to place these capacitors as close as possible to the esc - not halfway down the leads.
We will have to be careful not ot hijack this thread but here is some more info I picked up
Rule of thumb
There is a huge amount of conflicting discussion but my earlier posting appears to be the best and most accurate guidance. One point to consider though. Inserting a wattmeter between the battery and esc lengthens these wires by quite a few inches! There are many postings saying you should not use a wattmeter when pushing the current and or voltage limits of the esc. Use a clip on current sensor instead and a voltmeter across the battery leads, mutiply the results to get the watts.
Another point made often is adding 1" between battery and esc is lengthening the total wire length by 2". Most articles/postings/calculations are talking about this total length!
Edited By Ian Newton on 10/07/2013 22:37:22
Chris. Yes, that is one of the many useful articles that I also found. Much is easy to understand but some of the articles were between designers of esc's and electronics engineers were very technical (and quite heated in some cases!!)
Edited By Ian Newton on 10/07/2013 21:56:41
Chris / Phil, I do beg to differ in general principle, but I have done a lot of research on this subject as I am building a 72" wingspan Lancaster with of course 4 wing mounted electric motors. To do this I will need to extend either the three leads between the esc and motor or the 2 battery to esc leads. The recommendations from the perspective of the esc is to lengthen the 3 leads (which can, within reason, be lengthend as much as you like), but this is not always possible/desirable. If you lengthen the 2 battery leads then you do risk damage to the esc, and the manufacturers do not recommend this. The likelyhood of damaging the esc is dependant upon a number of factors. However, If your esc is capable of supporting 1 or more cells than you are using (e.g. the esc can support up to 4s LiPo and you are using a 3s) then that gives some margin to extend the battery leads without to much worry, as long as it is only a couple of inches. Damage may not be immediate but could have an accumulative effect. Basically it can damage the capacitors across the battery leads at the esc and at some point in the future these may fail. If you are near to the limit or wish to make a significant increase in the battery lead length then further capacitors (at the esc) can be added in parallel with those already mounted on the esc. The electrical characteristics of these capacitors is quite important i.e. you can't use any old capacitor. I do have lots of links and further info if you really want more but it gets quite heavy! (I am an electrical engineer - as opposed to an electronic engineer- but some of the theory in some of the items does make hard reading). It is quite likely that you will get away with this mod, certainly in the shorter term but if you are running close to the current and particularly voltage limit of the esc you may experience either immediate or, more likely, early failure. I know in the past I have lengthened the battery leads with no apparent problem but in one case (used on a 6s LiPo running at the esc max voltage rating) I did suffer an immediate failure which at the time I put down to a faulty esc but I now believe I pushed it too far!
Perhaps this is a suitable subject for an article in RCM&E?
As Phil says it is hard to make a judgement from here but I would suggest that if the bond is good and the adhesive is solid (try sticking a scalpal blade into the glue, if it penetrates easily it is no good if it will not penetrate the glue it is probably OK - as you know epooxy sets pretty much rock hard!)
From what you say it is unlikely that the adhesive has degraded. I suppose you can kill two birds with one stone here. If you warm the adhesive and hardener either in hot water or the microwave any crystalisation should be removed and if you mix it up while still nice and warm it should also set well. I have experienced these 'rubbery' setting results when the ambient temperature has been too low but never had a problem at a reasonable temperature (say 15 deg C and above). Setting times do increase the lower the temperature and I once had a mix that was made and applied when it was about 5 Deg C which never went off even when eventually brought into the house and warmed up (a good excuse for me to double glaze and heat the shed, now I never cold!). As your wing root join is such an important one it is important that you are happy it is sound.
Two possibilities: How old is the epoxy resin? It can 'age' especially if stored in colder conditions when crystalisation can occur - but this should be visible - I have read that this can be recovered by standing in warm water (50 dec C) but have no personal experience of this.
The other possiblility, especially considering the cold spring we have, is that it is not warm enough to set properly. The glued items should be in an environment where ideally the temperature is 20 deg C or greater until set. If it is cold then try heating the adhesive and hardner either in warm water or in the microwave (only for a few seconds though - you only want it pleasantly warm) before mixing. This will aid setting but be careful - the warmer it is the faster it will go off! It will also be more runny, which in some instances can be useful but in others less so!
Martin, Looks good. I wish I had turned my axles inboard and then added the covers to the legs as well. It was only after I had finished them that I realised it would have added that additional bit of semi scale effect.
Take a look at page 34 on this link for the 'AVTUR' fuel filling point. http://www.scalemodellingnow.com/wp-content/downloads/library-zip/set184-PRL-Ac-TucanoT1-GoldenJubilee1952-2012.pdf
Then look at page 4 once you know where you are looking at.
Edited By Ian Newton on 18/04/2013 21:47:09
Edited By Ian Newton on 18/04/2013 21:49:49
Best way really, unless you're an aerodynamics expert (counts me out!). A combination of experience, gut feel and it looking right no doubt works well for you - I don't have sufficient of any other than maybe knowing if it looks about right but I am learning slowly
Edited By Ian Newton on 14/04/2013 19:54:31
A very close guess Nige - by my calculations the total wing area was 0.234714m2 (364in 2) and would be reduced down to 0.212492m2 (329in2 ) i.e. a reduction of 9.5% to 90.5% of original so that is a reduction of 35in2. Using these figures and knowing the finished weight of your model will let you work out the wing loading in each configuration.
Thanks Nige. I think so too. It must make you feel good seeing and hearing of so many enjoying your creation - and so it should. I must say I am really tempted to make a new set of wings as per your recent posting. As I used Phil's removable wing modification it would't be too much work. I will have to give it some thought and decide on prioities. I had put aside my intention to build Tony Njhuis 72" Lancaster, for which I have everything ready to start, while I built the Tucano. I thought the extra practice of building from plan on the Tucano would be beneficial before commencing the Lanc, as I have only built a few completely from plan before. At least I am starting with the MyHobbystore CNC wood pack and plan on that one,rather than buying the wood and cutting it all myself.
Just received the pictures from yesterdays maiden flight (Thanks Bob):
Moment of truth
Strong gusty wind made landing hairy
Edited By Ian Newton on 14/04/2013 12:43:30
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