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Member postings for Dave Bran

Here is a list of all the postings Dave Bran has made in our forums. Click on a thread name to jump to the thread.

Thread: Brrr chilly
10/12/2017 11:54:15

I was on a steam haul rail trip yesterday, Due to numbers at the destination (many trains but only ours steam), we were moved much later return, and ended up waiting for our train to be allowed to return from sidings, standing outside the station in the open (in spasmodic light snow) for over an hour and a half, to then having managed to get away within five mins of schedule be bounced from loop to loop on the ECML by faster delayed trains, this on a train with minimal heating.

Arrived back in JUST enough time to get the last transport home with all the Sat night Drunks..............lovely..................

Thread: Wish to use 12v dc charger for lipos and Nimh at home on mains supply
09/12/2017 06:22:54

I have a number of PSUs used from time to time to feed chargers, some ex-computer, some industrial fully adjustable stabilised lab/bench, but the bank of NIMH chargers (10 of!) I use for the school club are powered by these little devices, three of them. very small, very quiet.

**LINK**

I used to suggest these, HOWEVER, I do not think they are available now AND anyway the price was only £12 each retail when I bought!!

A point with regard using car battery chargers as PSU. They are not! There are also so many types with and without regulation/boost/auto trickle that a blanket "use this" is IMO imprudent.

While I rarely field charge these days, I have a number of very large capacity 4S/6S LiPo which subject to charger input do what I need. They also drive my engine starters. A "Sakura" car engine starter is always in the car anyway and despite being tiny I once used it to start a 7.6 litre 6 cylinder petrol! No more stone age heavy lead acids!

Thread: T9 Hobby Sport
08/12/2017 17:51:55

Banggood Lithium orders always take near the max timing stated, especially if you are not paying for an accelerated service, due the the carrier restrictions they face. My last few orders of LiPo from there have come in via Sweden.

The std service is 20 WORKING days, and usually very close to that.

Of the last two HK Euro orders (for 2200 3S), the first order of three had one with a shorted cell, and the replacement sent came through with one cell at 2.8V (which recovered OK)

Thread: RCM&E December 2016 Magazine
06/12/2017 09:33:41
Posted by Steve Ralph on 06/12/2017 09:17:34:

I got my mag today by post, but the 20 page jetsupplement is missing.

Steve.

Shame I didn't see that earlier as mine got torn in half and binned without reading!

Thread: Winters Here Who's Been Flying ?
05/12/2017 07:11:23

I chose to go Outdoor yesterday instead of the usual Indoor, lured by a forecast that failed big time. Wrong choice.

Dull, extremely damp air, ground sopping wet, worm cast slurry going everywhere it shouldn't, wind swirling everywhere.

And?

I'll be going again today for more of it................................

Thread: Nickel based batteries
05/12/2017 06:41:22

NIMH chargers work by sensing the negative dip that occurs as a pack reaches full charge.

If you repeat charge the charger will attempt to charge until it gets another negative dip, which might be a while, and during this time you are pumping more current into the pack that it does not need.

Because it appears to charge again, that does not mean it was not fully charged in the first place.

Thread: Full size landings
01/12/2017 21:27:47

I realise this is a long while ago but a friend and I taught a Dan Air Pilot (on Comets) to fly models.

He could manage orientation APART from the landing, when he had to stand looking the way the plane was flying and look back over his shoulder.


I always worried about his passengers......................................

Thread: Dihedral in flying wing design?
01/12/2017 10:37:43
Posted by Engine Doctor on 01/12/2017 09:48:29:

The Zagi by Avicraft had a small amount of dihedral built in as wings were joined on a flat surface/table with top of wing flat on table. The taper of the wing section gave it the dihedral on the bottom surface.

Edited By Engine Doctor on 01/12/2017 09:49:15

Yes, that is so, which is as I said above, normal practice for flying wings and a fair number of low wing aerobatic planes.

01/12/2017 10:35:36
Posted by Mark Kettle 1 on 01/12/2017 06:37:55:

No dihedral mind on this one.

No, anhedral due the wing taper with washout.

Thread: Flaperons, air brakerons?
01/12/2017 10:23:40

As I fly from a short patch with upwind mature trees and a downhill slope in the usual wind direction, stopping is an issue esp on low to no wind days for some models and I have flapperon/spoileron fitted to ALL my plane inc scale.

Small amounts of up aileron spoileron really do help and do NOT result in control loss (having been tested at height of course!). I do NOT mix elevator and control this normally, the main action being on a side slider I can adjust on the fly just like any other control. They are also useful to hold a model down and prevent bounce once landed, especially in a crosswind.

Doing this I can stretch the approach using flapperon and shorten using spoileron at will, and rarely ever have to go around.

Thread: Dihedral in flying wing design?
30/11/2017 18:54:33
Posted by David Hall 9 on 30/11/2017 17:47:06:

Thanks for your help... I have a further question about airbrakes for a wing, so will make a new thread. ..

I have only once needed to add speed brakes, this was to a pod front delta wing. I fitted a servo which projected two rods each side out of the pod fuselage and pushed tape hinged plates out either side close to the CG.

This was quite effective , but not really needed generally as most of mine were powered, and if you run a prop slowly, it causes a lot of braking drag.

29/11/2017 16:29:20

All my own design aerobatic flying wings and deltas (and that is a lot), whether wings are swept or "plank" in plan, have the two wing halves glued together upside down, so the tapering section from root to tip creates some dihedral.

Thread: What's flying over your house
28/11/2017 13:39:44

At our flying field this morning, a drone of twin radials and an olive C47/DC3 with invasion striping flew over from the west presumably heading Biggin cct.

About 15 mins later the usual Spitfire came closer than usual to our field after take off from 29 due the wind direction.

Thread: Legislation Proposal at last
26/11/2017 12:15:03

So, here we go recycling all the old comments all over again.

Does anyone here bother to follow the AAIB and other Government reports on drone incidents?

Been very VERY quiet for quite a few months.

ALSO, to the "anti-multirotors in clubs" brigade - FACT - Every MR sport pilot who has joined into two of my clubs has gone on, if not already able, to fly helicopters and fixed-wing, and is an asset to the club. And a few competent FW pilots have added MR and Heli skills to their portfolio. In a lot of cases I have done the cross format familiarisation, and its been a pleasure, so YOUR LOSS.

The worst experiences I have personally had have been with CAA certified pilots, who in my now quite extensive experience are in actuality shockingly clueless about safe use of video eqpt, safety rules, etc.

The last one I was in contact arrived and turned on while using my (in use) video frequency. When asked he didn't know WHAT his video frequency was set to, or how to access it, or the process to check receive before transmit to ensure interference free.

He was also quite happy to have a large and powerful fixed wing twin prop "drone" untethered and powered up in the pits, some of the time even facing his own legs while he played with the radio Tx settings with the tx buried into the back of his "faraday cage" 4x4! He didn't see any problem when it was mentioned, so one must assume he behaves similarly when out on jobs with public in the frame.

Thread: Need an Electrical Appliance Item Quickly?
25/11/2017 08:18:27

We had a voltage flash surge at home on Tuesday that stopped our freezer compressor dead (and did other lesser things around the house). I bodged it back into life, but we obviously needed and so ordered from an online supplier offering very fast service, paying extra for next day, delivery Wed.

On delivery and unpacking by the delivery man (in time slot mid afternoon) it was trashed, severe door damage and smashed top valance and hinges.

Next time we could see one in was Fri, but we needed one quickly, so agreed a replacement.

On Friday, I get a call to say an hour away, early one slot. (note:- with a different courier firm chosen by sender)

I get a second call ten mins later to say it had been loaded in the van on top of a washing machine, driver had not seen it was stacked two high, and it fell off while van on move to us, and guess what........severe door damage.

So if you want to waste your time, buy from Appliance Direct, SOME bits may eventually get to you, but I hope you enjoy waiting in and like wasting your time.

And now? Well its Black Friday weekend, and all the websites are seized by the pressure and the stores heaving......and all the delivery slots gone for a week or more...............

Thread: B-24 Liberator foamy pnf
22/11/2017 14:46:14

Thanks for heads up, this one is a must for me!

Thread: Fairey Long Range Monoplane for indoor flying.
20/11/2017 08:22:12

Thanks for update.

17/11/2017 21:52:03

Well, your flight test obviously proves me downright wrong, but I'd have sworn that 35" span of anything would out power the Parkzone set on 1S!!

Watching with interest!

Thread: E-Flite Lipos Shock, Horror! A Serious Waste of Money?
17/11/2017 12:28:18

No Worries!

Related to recent posts, I have just been checking batteries for the after school club I run.

When I got to the batteries for the three JP Twister Quads, either 550mAh or 600mAh 1S, not used for a couple of months, I found:-

1. The Nano-Techs only required a max of 6mAh to cut off (so no actual charge needed)

2. The IP's all required between 50 and 100mAh

3. The Overlanders also only required a max of 6mAh

3. The Hyperions had dropped the most, requiring between 150 and 250 mAh

If you tried to guess their relative ages from these results you'd probably be wrong! Had a noticeably higher fail rate on Hyperion and IP than the others.

I have tended in recent years to fly i.c. more in the main season and EP more in the winter. I keep the batteries in the warmth for 3-4 hours before placing into defrosted car and do not normally suffer less duration due temp.

It's planes like the truly excellent Durafly/HK EFRacer and EFXtra, FMS Marauder, Radian, and a few own design fast Deltas that have tipped the balance this year more to EP, even in main season. Flying at least twice per week indoor sports hall and home/garden with micro quads has pushed it even more EP

3 of my i.c. planes and four i.c. helicopters have not flown this year at all (though some have!). Every single EP plane has flown at least once.


17/11/2017 06:38:42

With far too many LiPo from 40mAh 1S through to 6000 mAh 6S, (over 200 packs in all) my experience and observation of others:-

1. Most "Big Brand" LiPo are rubbish. You pay a heavy price for a label.

2. "Good" makes seem to go in cycles, several batches good, then a less than perfect set. (I usually buy sizes in 3 to 5 "sets" with bigger sizes, 10 plus for lower capacities)

3. Recently for the first time ever I have been supplied faulty battery packs from a China supplier Euro Warehouse, one 3S with the middle cell shorted 0v making a heavy 2S, a 3S pack with cell3 under 2v. Generally more erratic cell voltages across each pack. This has never been a problem till recently. They replaced immediately, but still...............a worrying trend.

4. Some 6S 5000mAh packs which were provided with a model bought from a particularly fastidious guy who always used storage mode, ones with ALIGN written all over them, and cost over £150 each, had his fixed charge/use/storage routine continued and promptly failed. One pack when taken out of overwinter store had one cell shrivelled to a dry husk!!! Ones I had already of "budget" make this size left as last used or full all survive to this day, several years on.

5. I have "Tipple" budget packs from 2007/8 which are still good and have never been "stored".

6. The small 1S/2S packs do seem to self discharge more than larger ones regardless of make.

7. A flying buddy has just bought packs from a well known UK based Internet supplier in the last two weeks. I have not seen these packs for many years, and the labelling, now extremely unusual dimensions, lack of power connector, and very archaic balance connector type (which uses a 6S pins size connector for all inc 2S and 3S as he bought!!) all points at the supplier dumping really old stock on him. He stupidly didn't check cell voltages on arrival but says they took a very long time to charge first time. One is already showing signs of distress.

8. Many tiny 1S packs will not like 2C plus charging no matter what their maker says, the relatively simple charger circuitry is not fine enough control to protect them!

9. My commonest pack size (and I suspect many others), 2200mAh 3S of around 30-65C is currently biased towards HK Nano-Tech. These have recently though ended up failing (after MUCH use) by getting warm under 1C charge or erratically having one cell stray over 4.20v (regardless of charger make/model). Not the fact that they fail then, but HOW they fail! They STILL deliver power for decent duration but are of course taken out and given a salt water bath to oblivion. Thes packs are now untrusted and have to be watched like a hawk above normal when being charged. In contrast every Gens-Ace battery I have ever had has never shown any charge issue but has rapidly failed to 20-30 seconds of power and excessive internal resistance, and every "Tipple" has gone on and on and on until the max charge voltage per cell has over long time reduced too much.

EFlite packs? I avoid like the plague! Poor power, short life, swelling even after careful treatment while used only on the model they are stated for!

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