MattyB

Agreed, but it is probably more important to mount these in free air these days than 5 years ago - most mainstream ESCs seem to have been "slimmed down" over time to fit in smaller fuselages, but that has resulted smaller heatsinks and an increased requirement for good airflow.

Yes, gluing the top of the ESC to the EPP is not a good idea as that is where the heat sink is and the foam is an insulator. It is best to attach it loosely with cable ties so that air can get round it (if you have space to do so).

Don't just get your friend to check, buy a wattmeter - it is essential kit if you want to avoid frying components and will pay for itself quickly for that very reason! Re: the battery voltages, that is slightly out of balance but not necessarily unrecoverable. I would put it on a slow (0.5-1C) charge and see if it evens up at once it has reached full charge, then run the wattmeter test and recheck the voltages afterwards. If you can check cell IR that would be good too, but your charger may not have that functionality. PS - What voltage have you been storing your batteries at? That can have a significant effect on their longevity and IR. Edited By MattyB on 11/05/2017 09:59:57

Posted by FilmBuff on 10/05/2017 18:01:45: Not another thread of negativity and nay-sayers. ...It was not so long ago that many on this forum were saying "it will never happen, BMFA are to clueless/useless/toothless etc" There would be a lot fewer of us "nay-sayers" if the BMFA shared the opex estimates transparently in writing with members who wanted to see them rather than pointing us to materials that only include details of the capital investment required to get to the end of phase 1 (and yes, I have searched for minutes of the 2016 AGM on the BMFA site but they do not appear to be available). The lease is signed, so there should be no commercial sensitivity to opex costs being shared. I can only think of three reasons why they have not been published yet... Estimated opex costs haven't been calculated (highly unlikely, especially given Keith's comments above); Confidence in the accuracy of the estimates is low, so the BMFA Council do not want to be on record as having calculated them "wrong" (understandable, but if true this just indicates more work is needed to increase confidence in the figures); BMFA Council do not believe members have any interest in the figures (probably true of the majority who did not/were unable to vote at the EGM and are presumably ambivalent to the project at this point, but that is definitely not all members). Edited By MattyB on 11/05/2017 09:16:25

Discharge units - 3 required at ~$12 each: Edited By MattyB on 10/05/2017 22:09:39

Yes, completely possible but your charger is unlikely to have a sufficiently high discharge rating for it to be worthwhile to do in parallel unless it can do regenerative discharge into a large capacity lead acid battery. A better solution is a discharge rig - mine is rated to ~300W and is based on this design...

Yep, this is either an overpropped powertrain, a time expired battery or both. The numbers from the watt meter will give us a much better idea, especially if tested over a min or so.

Phenolic sheet, that's the stuff! Most things are carcinogenic if you look hard enough though, so I would not worry too much about that as long as you only prep it in an area with good dust extraction.

Interesting. I like your second idea of the foil tape - we did retrospectively try some aluminium sheet, but found it acted as a heatsink and cooled the wire at each end of the cut.

Posted by Keith Lomax on 10/05/2017 15:15:30: Grants is an interesting area - when we have previously made enquiries, we were told that these mainly work on match funding and now that we have something to show this is now in a position to be further investigated. Unfortunately I no longer have a copy of the report on grant funding the BMFA published prior to the EGM. From memory whilst it did indicate that match funding was the predominant mechanism these days, it also stated grant funding of any kind was extremely hard to come by from the EU or lottery unless economic development (i.e. jobs and GDP increase) could be shown. Perhaps this report could also be republished on the website now the lease has been signed and any confidentiality concerns are behind us. Edited By MattyB on 10/05/2017 16:24:06

Posted by Keith Lomax on 10/05/2017 15:15:30: Posted by Steve J on 06/05/2017 09:28:09: Posted by Andy Symons - BMFA on 05/05/2017 11:37:52: Day pass for flying is £6. Has the BMFA published an estimate for the annual running costs of the NFC? I am curious as to how many £6 day passes it would take to cover it. Steve Yes - there were some figures presented at the AGM - these are based on estimates for usage and costs. This is still very much a work in progress as we will learn from experience. These are the materials on the NFC website that the BMFA presented at the AGM (presentation dated Nov 2016). There do not appear to be any estimates for usage or opex costs (other than rent); the main figures are all the upfront investments (capex) for phase 1. Missing are security, grass cutting, utility bills, any additional HR costs etc. Only broad brush statements on opex are provided ("Income from the centre is derived from multiple sources - revenue from model flying and non-model flying activity, sponsorship and donations" etc.) - no figures are provided for the sponsorship from insurers for instance. Were additional opex figures presented that did not make it into the presentation published online? If yes that should be corrected asap for reasons of transparency. If no then your statement that the estimated annual running costs for the NFC have been shared with the membership does not really appear to be correct. Edited By MattyB on 10/05/2017 16:43:49

OK, based on 400Kv and the fact he already has a large 4 blade prop fitted there are essentially two options: Fit a higher Kv motor more optimised for 4S operation on a 2 blade prop; If your motor can take it, go to 6S on a two blade prop of similar diameter to avoid ground strikes, maybe with a tad more pitch (eCalc or similar can probably suggest some props). Ultimately I am still not sure we understand the problem the OP is trying to solve. He needs a certain level of power to get authoritative performance, and that needs to be generated whether the model runs on 4 or 6S. What is "a huge drain on the 4 cell 3700 battery" in real terms i.e. current drain in A? What is his desired duration of flight? Without answers to these questions we are just guessing Edited By MattyB on 10/05/2017 15:59:32

In our mass build it was the quality of the (wood) templates that were the defining factor - they started off great, but the more wings we cut the more damaged they became and the more rippled the wings were. Getting the right (synthetic) material for them is key - I now hav some of the propoer stuff, but it's so long since I bought any I can't remember what it is called!

Posted by willhappy on 09/05/2017 22:21:13: hi there all Been looking at Matty B vid. i have been looking at power supply for a hot wire cutter and saw this power supply the Fusion 200w twin adjustable at sussex model center would this be any good say for a 1 meter bow. will Yes, that will be fine. As others have posted though there are cheaper ways to do this that avoid you purchasing a new PSU (some chargers have a foam wire cutting output, and you can also use a brushed ESC plus 3 lipo setup too).

Posted by Simon Chaddock on 09/05/2017 20:14:15: "ain't designed for power dives" That would be my take on a foamy. At high speed it only takes the tail plane to flex under the load of the deflected elevator and the net result is no 'elevator' effect at all or even control reversal. That is somewhat of a sweeping statement - sure there are some floppy foamies, but models like the EFX, EFXtra, Roc Hobby pylon series and the Mpx Dogfighter are well reinforced and good to >100mph in stock form, more with a few mods. Horses for courses. My gut feel is that the OPs issue in this instance is most likely to be CG related, but if worried about flex check the linkage run thoroughly, upgrade the servo ff needed, check the elevator horn is solid and reinforce the elevator itself with a few pieces of inset carbon strip and CA. Edited By MattyB on 10/05/2017 11:32:35

Posted by flight1 on 09/05/2017 18:12:51: The problem you might have is you are using a 4 cell battery pack and the plane requires a 6s battery, you could always use two 3s packs in parallel to get the 6 s as its far more cost effective Errr no, that's wrong on two counts.... There is no way of knowing from the OP if the model is intended for 6S operation - he has not included enough detail. Throwing a 6S battery at it without understanding the specs of the powertrain is likely to end in tears. If his current drain is already high it is only going to get (dramatically) higher on 6S with the same prop. 2x 3S packs in parallel is still a 3S pack, but with twice the capacity i.e. 2x 3S 2200 in parallel = 1x 3s 4400. To get a 6S pack you would need to connect them in series, but they then still have the same capacity as labelled i.e. 2x 3S 2200s in series = 1x 6S 2200.

Posted by ericrw on 09/05/2017 18:00:17: My FMS Mustang flies with a four bladed 16x6 prop and a wingspan of 1600mm. However, there is a huge drain on the 4 cell 3700 battery. To overcome this problem, I have been advised to use a two bladed or a three bladed prop. Could anyone on the forum, advise me of what size to go for with either a two or three bladed prop ? Appreciate any advise !! FMS do not make a 1600mm Mustang to my knowledge - lots of 1400s and definitely some 1700s (though I am not sure they are still available), but no 1600s. That means it may be a Starmax, or you may have the span wrong in your OP. Either way we need more precise details of model and motor specs (especially the Kv) to make a recommendation. However it is now pretty standard to re-motor and change the prop on the 1400mm foamie warbirds for 6S operation; they are all a bit undercooked on 4S. If you go to RCGroups and search there on "6S [manufacturer name] mustang conversion" you should get lots of hits recommending powertrain components. Posted by ericrw on 10/05/2017 09:16:12: I`ll try two 3cell batteries; but is it possible that faulty ESC could have an effect on the power drain ? It is highly unlikely the ESC has anything to do with your problem - remember it is the motor and prop specs that define the current draw, not the ESC. Do not go 6S (2x 3S in series) without doing some calculations and understanding what the current draw will be first; if you do your current will increase dramatically (probably around 2x given the dramatic increase in voltage) and it is almost certain you will cook the ESC and probably the motor too. You have to apply science and maths not guesswork if you don't want to fry components - time to do some reading on how electric powertrains work. Edited By MattyB on 10/05/2017 10:54:14

You want big, fine pitch props for 3D where thrust is more important than speed. Without specs on the model though (span, weight etc) it is impossible for us to recommend a motor.

Posted by Steve J on 09/05/2017 18:41:27: @MattyB Open class subcategory A3 means that you don't have to be a member of an association or club to fly models below 400ft. All that you have to do is register, do some online training, an online test and fly away from uninvolved third parties (UAS.OPEN.60). Right, but how do I do that at 99% of slope sites? These locations are public access; they have to be for us to get there to use them. That means there is always a decent chance of the public turning up; indeed many of the best slope sites are well known viewing points, and therefore destinations for walkers and the general public. My home slope at Ivinghoe is a good example - it will undoubtedly need an OA as there are hundreds of walkers a day in good weather. That should not be an issue for us given we have a longstanding club with a good safety record, but many other well loved slope sites do not have a club overseeing them. What of them? Are we back at the idea I floated a few months ago of a UK wide soaring association to document and oversee these sites (link)? Edited By MattyB on 09/05/2017 19:38:30

Posted by Steve J on 09/05/2017 16:10:23: Posted by Biggles' Elder Brother - Moderator on 09/05/2017 13:13:58: EASA's plan to achieve this (whilst still allowing model flying) is to concentrate all model flying at a relatively small number of well documented sites. Citation needed. Steve Having read the document most of the way through now I concede I can't honestly tell what their intention is. Ostensibly safety is a priority, but being cynically minded I started from a position similar to BEB's that this is mostly about freeing up airspace below 500ft for commercial gain and increased tax revenues. If EASA were to do that in line with Amazon's vision I am quite sure we would be limited only to defined sites, which could effectively mean the end of legal slope soaring in locations where there is no resident club or "official" history of RC usage. Even so, I can see that (even if that is the intention) there is potential to escape some of the most onerous requirements depending on how the document is implemented within a member state. As currently worded it all seems to hinge on who the competent authority is (i.e. the CAA or BMFA) and the exact nature of the powers they can delegate/operational authorisations they can grant to clubs or associations. For example: If the competent authority is the CAA, can they grant OAs to BMFA/LMA members as a group (club and country members), or only specific clubs in defined locations? What requirements can be negotiated out under and OA, and what can't? Registration - presumably not? Height limit - presumably yes, but under what conditions? I guess we will find out over time, but it seems like this is very high level stuff and there is a long way to go before sufficient detail is added to enable us to understand the end state. It does look slightly better than draft 1, but my underlying concern remains that big players like Google and Amazon lobby hard to reduce or eliminate the powers of CAs to delegate authority and implement this differently across individual countries. If that occurs the very small number of modellers EU wide (from an electoral standpoint at least) stand little chance of coming out on the winning side against the big money. Edited By MattyB on 09/05/2017 18:06:27 Edited By MattyB on 09/05/2017 18:10:13

Google and ye shall find... RCGroups thread MF thread

I am a little surprised there is nothing on the BMFA news pages regarding this latest document from EASA. Given they have been intimately involved in its creation I would have thought a communication would have been ready to go up the moment it came out? I am very interested to hear whether it will publicised as major improvement or a disappointment compared to v1 that they were not very complimentary about...

Yes, they work fine but remember they are SBUS only - if using conventional servos you will need to use an appropriate decoder such as the FrSky one or an XPS X10+.

Ooops, forgot the link in the above post...

Maybe you need to ballast it for high winds like a sloper... PS - When converting 109lbs to kg (yup, I'm a child of the metric age) Google helpfully informed me that this model r model weighs exactly the same as one of the worlds most untalented celebrities...! Edited By MattyB on 08/05/2017 23:11:41