Simon Feather

AHHHH problem solved The act of explaining to someone else usually does it, and the penny just dropped There is another harness involved as well, using multiplex plugs to reduce the number of connections to the wings, and that's where it's getting the power. Grr, ignore me, I shall now go away and sort out the job properly.

I have a conundrum that I'm puzzling over... I've built a wiring harness to power the retracts on a model using a separate battery. No problem with that, I have done it many times before; it's just a Y lead with the red wire cut where it goes into the receiver, and then a new power lead spliced in. It's good practice, and in this particular case, necessary: I'm using 120 size Eflite retracts and the voltage drop when they operate is enough that they don't always operate reliably without the dedicated power supply. OK so far. The harness works as expected using a servo tester. The harness works as expected using a Spektrum AR610 receiver. However.... when plugged into the AR8010T in the model something very odd happens. The retracts work WITHOUT the separate battery being connected. I've checked with a servo plugged in instead of the retracts, and that operates too... I didn't just cut the red wire where it goes into the receiver, I removed a section about 1cm long. Somehow the A8010T is getting power into the servo, and enough power for it to operate reliably. I've been doing hobby electronics since I was about 14 and pride myself on soldering neatly, but I will still go and check this harness over again thoroughly... meanwhile I wondered if anyone else had encountered this. I've got a couple of theories involving inductance as to what might be happening, but I'm struggling to see how any of them can result in enough direct current for the servo to operate! I'll try a fizz ring just in case, but I can't see how it can be that. I'm fairly sure plugging the additional power supply in won't cause an issue - that red wire is cut, after all! I'm sure there is a logical explanation, but it's a curiosity. Simon

Well, thanks to colleagues at the pitch I've managed to get a few shots of the GTC, so I've cobbled together bits from a couple of different videos. Mix and match quality I'm afraid, but hopefully gives an impression. That huge wing lets it fly very slowly, I didn't need the flaps. Indeed when I tried them they had little noticeable effect. It can fly quite fast too!

It's been a long time since last posting here... apologies for that. I had just finished fettling the engines on my enlarged GTC, then the weather closed in.... then we had further lockdown... however now we have been let out again, I've managed to get the model back down to the field, completed my engine and ground running tests, and she flew earlier this week. As a reminder, this is the Grumpy Tiger Cub, but enlarged to 70" wingspan with a pair of OS 52 Surpass on 12x6 props. It's built straight with no right thrust offset. I reduced the size of the original strip ailerons to around half, and added flaps. The maiden was fun! As expected, I needed a boot full of right rudder to counter those two engines, feeding in more as I throttled up - so just like full size. But it was a bit twitchy on the maiden as I had rather too much throw on the ailerons. Second flight was much calmer after winding things down a bit, and I've now had about half a dozen flights with her. Fantastic - there is a huge wing area so although it weighs about 10 1/2 lbs all up, it will fly really slowly.... and also quite fast! Landings are a treat, it didn't need the flaps and I've not used them yet. The sound is utterly awesome - cruising overhead it sounds just like a real full size plane. The weather looks set to hold at least for the early part of next week so I'll try and get some flying shots. I'll fly it a bit more, then aim to finish it off - the fuselage needs recovering: I used HK film for the wings and empennage, but ran out so used some Easycoat for the fuselage, as it was a very close colour match and HK were out of stock of the pirate blue I'd used... but the Easycoat has wrinkled terribly and delaminated in many places, so it's going to have to be re-done; and I'll add a canopy and pilot, should then look a treat. Brilliant and great fun - thanks again Peter. Simon

Yes, non-shrinking dope. I found meths better than water for cleaning the sticky balsaloc residue off the iron, but it's a bit exciting as of course meths on a hot iron possibly isn't the best combination... don't use a sock on the iron though, in this case, the balsaloc makes a right mess of it! Ceconite can shrink a LOT so beware of overshrinking with the iron as it could damage delicate understructures. Testing is the key.

? ok.. so maybe a bit more work, depending on what level of finish you're looking for! I love the stuff, such a nice finish and as you say, significantly cheaper than Oratex. We may have got a bit off the OP's topic.... but an interesting discussion nevertheless. Cellulose thinners got the VQ sticky stuff off for me!

Murat - in terms of ease of use, it's not really the same at all - Oratex is self adhesive, and comes in various finishes; Ceconite is completly bare. You need to glue the wood (I used balsaloc) then iron on and shrink, then prepare the surface with a couple of coats of dope, then paint and other finishes... so it's a lot more work! but it gives a beautiful linen finish... and it's incredibly tough! I got mine from LAS Aerospace Simon

I've done exactly this.... recovered a VQ ME109 I used cellulose thinners from a large 5L tin I bought a year or two back to clean down the wood, it's smelly but it did the trick. I used this as a test for covering in Ceconite as used on microlights - it's beautiful easy stuff to work with, but is not self adhesive. I put balsaloc on the wood and stuck it down with that with an iron in the normal way. Two coats of dope then needed to fill the weave, coat of primer then the top colour, and I added a matt lacquer to even it all off afterwards as I was using a mix of celloluse and B&Q tester pots! With the VQ heavy base build the result hasn't come out light, but it definitely flies well. some pictures of the covering in progress and the end result. Simon

Where does the grass grow in Yorkshire? ... In t'urf

Martin - I'm not a legal bod so not familiar with legalese.... but I'd be very surprised if the forum were using obscure legal terms, I would expect it to be using plain English! I have been around building of websites, content management systems and generalo coding for a very great many years, and so my suspicion - perhaps an admin can confirm - is that there is a token in the header of the "latest posts" thread which is not being populated, perhaps because the token has been mistyped. I suspect it's supposed to say something like: Showing topics posted in 'Latest Posts' for the last 365 days which would make a lot more sense! Simon

Hi Martin - I was observing the grammatical error in "Showing topics posted in for the last 365 days"... ? Simon

Much better! thanks! ?

Hi Bob - yup, the bigger e-Flites do seem to be a tad voltage sensitive! But they're the only ones I've ever really had that issue with.

Hi Mods - very minor quibble.... had you noticed the "latest posts" button shows "Showing topics posted in for the last 365 days" [sic] as a subtitle under the "Latest Posts" heading? It's the same whether it's the button added site-wise, or the view we were encouraged to add ourselves in the early days. Thanks for making the default text blacker ... it's definitely better. The new RGB values are (18,20,22) rather than (53,60,65) - so still not totally black, it could probably go all the way to (0,0,0)! Is there any way of resizing images once added to a post? I've not found one yet, if so. I've seen a lot of images posted that take up a whole page on my large screen when displayed. Thanks again, it's really getting there. Simon Feather

I too always use a separate power supply now for electric retracts: a simple BEC and 2s LIPO works a treat. There's another reason for doing this besides the risk of stalled retracts momentarily dropping the voltage to the receiver; I found with some retract units - notably the pricier e-flight 120 size ones on my Zero! - that driven from just the receiver power supply the retracts were unreliable, particularly if servos were operating at the same time. Just not quite enough juice to power them... sometimes they would work, sometimes not, sometimes one would work and the other not... a separate power supply and no more problems. Remember to cut the red (positive) wire in the connection from the retracts to the receiver though. Take a moment with pen and paper to work out the wiring harness needed is worthwhile.