Graham Davies 3

Forumites, I need your collective experience... Apologies if this has been done before; the search was not forthcoming. I have just installed a pair of Emax ES08MAII servos in the wings of my latest build. Whilst checking the linkages were bind free, I found that the servos appear to have no power. If I rest my finger lightly on the aileron, the servo does not have the power to drive it. The 'gearing' is the same as in my tempest, so it's not that I am asking too much of it. Both the servos I recently bought are the same. They are on extension leads, but I have run them direct with the same result. They appear to be weak. I suspect they may be forgeries. Prior to this I had some no-name metal gear 12g servos that had no idea where centre was. I'm aware that these are cheap products, but both are no use whatsover. I also understand the philosophy of pay little/ pay twice. I am clearly paying twice! I do accept the consequences of my buying decisions... Surely there are some useable 12g size servos out there for under a tenner each? The problem is that there is huge choice, but no provenance unless the name brands are used, and then the cost sky-rockets. What are you guys using, and do they centre properly and have enough power to get out of their own way? Thanks GRaham

Yak 3 is finished and ready to fly. Loosely modelled on G-OLEG previously owned by Will Greenwood and subject to this website, which is an excellent read: https://vintageaviationecho.com/yakovlev-yak-3/ Warbirds Replicas Kit. 55" Span, 5lb9Oz ready to fly (18Oz/sqft). Powered by a 5055 500kv motor on 4S turning a 14/7 3 blade. Static test give over a kilowatt, so judicious use of the throttle will be necessary! Maiden will occur some time in the future when the wind eventually drops...

Now they tell me. In the current weather I put my nearly completed Yak 3 outside, and now I can't find it...

I'm naturally tight fisted, so always look to spend the least I can, so am resourceful with materials etc. But not at the detriment of enjoyment. All my models are built, because I like doing so, and my most enjoyable models are usually a bit smaller. I don't find the same enjoyment when the model overhead has more time and money invested in it and all that's keeping it there are my thumbs. Let's face it, I don't trust them to hitch-hike in the right direction... BUT; I won't spend more than I have, and won't limit my spend if it limits my enjoyment...

Hi Jeffrey, I have 4250 size motors in a few models. Mine generally are lower KV to swing bigger props, but power is broadly similar. Mine power a 55" Tempest with 5lbs AUW (600kv on 4S spinning a 14x6) and a 44" span biplane weighing just under 6lb (500Kv spinning a 16x6). Think 46 2-stroke and you're probably in the ballpark. Graham

Great build log Andy. Really like the model. I've always had a thing for a pitts...

Love that Andy. Any details?

Looking good Peter. I'm sure the balsa will be fine. I've had many, many more models with balsa sides than ply, and never had an 'aft of trailing edge' breakage. The weight saved will be less energy to take into the ground should it come to meet you a bit faster than planned!

Thanks Alan, it's looking a bit more 'naturally weathered' now! I Can't remember exactly, but I may have been 4 or 5mm behind the recommended point for the maiden and I've now balanced 3mm ahed. I think it's at 65mm, but whichever, that was were I was relative to the plan position. Given how it flies, it indicates that the CofG is about correct now. There is one other smoking gun I found on the first flight; aileron alignment. It's not particularly easy to align them due to the washout. They never look quite right. I think I lowered the trailing edge of both prior to the second flight to reduce any reflex as this will not have helped. She flies really nicely now Graham

Looking good Peter, Don't worry about the servos or clevises. I used a single 3352 and it's fine. I used an auronaut folding prop with a boss that was larger than 57mm (I can't remember which). The hole is larger than the prop adapter, so I made some spacers top and bottom and then used a standard 57mm spinner. The prop slots need to be cut out, but it works fine. Graham

Warbirds Replicas Yak3. A few tiny jobs to do such as straighten the cowl, fit exhaust stacks, fit aileron servos, and the fun bit of panel lines, rivets, weathering. My first time spraying emulsion. First coats with a car spray paint gun. Went on OK, but with more runs than Alistair Cook... Second coats with an airbrush. Took ages but went on really well. Maiden next week, if all else gets done! Graham

Looking good Peter. I did the same with the ply reinforcement. I think i used fine glass cloth and epoxy. Regarding the folding prop (I need to give credit to Ron Gray for that one!), I went down an inch from the 10x6 I had been churning though because the 10x6 folder draws a lot more current. I've got a 9x6 on there, and it's fine in the air, but lacks a bit of acceleration. As such, this evening's launches were followed by the lowest of low passes, and the gentle sound of puckering... Graham

I made a little jig to hold the aileron upright and square and then drilled with my pillar drill to a depth stop. I was worried about getting central or breaking though. It's stable though, and aileron throws are tiny so seems fine. I reinforced the hole with some cyano too. Graham

It was but a scratch Peter, a flesh wound if you will... I was/ am concerned about the lack of material for the torque rod to engage with. It may be worth a small piece of ply inlaid to support this area. Mine have so far held up but there really isn't much to bite into. As an aside, mine now has a folding prop. The breakages were getting silly. The model lands flat and there is no way of knowing where the blades will be at point of first contact. Others have been luckier than me, but a prop every 3-4 flights is a bit much! I tried a 10x6; same as I sport on the 800kv/3S set up I've been using. However, it's a bit power hungry so rather than risk the smoke getting out, I've gone for a 9x6. It's pulling 38A static; around 400W so should be good. May fly tonight so will report back Graham

Morning Ken, Yep, I saw that and glazed over a bit! I understand I can use pretty much any receiver (except FASST, of course!). I was interested in suggestions. And maybe some pros and cons. I'm a bit old school having returned to the hobby 18 months back. I use a 9CAP with a 2.4 module and whilst it's plenty for much of my needs, the techie in me sees the benefit of some of the telemetry options. What I don't want to do is buy a TX and some RX, get the wrong one and not see any of these benefits... Cost is another one; as long as gear is reliable, I don't care what brand I use. But FASST receivers are a bit more expensive. This becomes a factor when pricing up a project, and has the effect of causing me to wait. I'm not keen on waiting; I usually then change my mind 6 times... Andy's brief summary was helpful because I now know a rough direction, and also understand a use for SBUS, which I didn't really get before! Graham

Thanks Andy, that's really helpful. It was hard to know what I wanted, as I didn't really know what was possible. Voltage sensor is a no-brainer. I now have a good place to start Graham

A conservative suggestion John, but a safe, nay, SOLID one. I'll consider that a banker/ fall back option. ?

This might seem like a "how long's a piece of string" question, but bear with me... Given recent FASST revelations, I feel that it's time to push the button and go with a TX16. I'm too vulnerable at the moment; my Futaba TX dies and I could be Donald Ducked! So, given that I only have FASST compatible receivers, mostly FrSky, so am happy with non branded gear, what receivers should I buy when I buy my TX16? The world, Rodney, is my lobster, but that tends to lead to option anxiety crises. I'm the same in the breakfast cereal aisle... So, what would you buy if you were me? Thanks all, you're too patient... Graham

My ebay special works ok too! Retract.MOV

Morning Jon, The cheapo one I bought seems to work well. It is being used for a mechanical tailwheel retract driven from a cheap mini servo. The whole set up including retract, wheel, servo and speed reducer weighs 40g, so it's all lightweight and 'low demand'. I guess horses for courses!

I can't comment on the T6K, but I solved a similar problem with the tailwheel retract on my Yak3 and my old 9CAP by using a servo speed reducer. £7 delivered from Ebay and does exactly what I needed. https://www.ebay.co.uk/itm/352752970945

Looking good Peter. It looks like I can now sort out the ballast issue. On my final flight this evening, rather than break the prop, which happens depressingly regularly, the firewall came off! I have had various balance/ vibration issues, so I think this has been coming. The good thing is I now have unhindered access to the underside of the motor box so can relocate the lead and kill off the vibration issues once and for all. Yours will be lighter, particularly at the rear, so shouldn't suffer these problems. Regardless of all this, it does fly really well...

Hi Matty, Apologies to all, this may go off-piste for a moment as this is an issue that I am struggling with. In my 'real job' I am trying to source compliant product to sell in the EU and UK. We WILL NOT breach regulations. One product we sell to schools is FPV cameras and transmitters. These have a clearly defined transmission spectrum. A spectrum that 95% of product available in the UK do not meet. Further, all product must be CE (now CA for the UK) marked. For this, a self declaration is required, but this must be backed up by a technical file. It's not enough to simply say "yep, meets regs..." Banggood used to supply this product, amongst others. However, they could not and would not provide the relevant declarations and technical file. They are acting unlawfully, sadly as are most UK suppliers of similar equipment. So as good guys, we can't commercially compete. Given this sorry state of affairs, forgive my deep cynicism regarding ANY declarations made or implied regarding compliance. I think any decisions about product lifespan are driven by purely commercial reasons, and compliance may only come into it as the various manufacturers use it to sling mud at each other. Our regulator, Ofcom, have so far done sweet FA to provide any clarity or protection. Free market? Be careful what you wish for! But I'm not bitter; we'll find a way. We always do. Graham

Oh my word. That is a thing of beauty. I am often humbled by the skill and artistry of our membership!

That has to be the best summing up of model styles I've heard!