Nigel R

That'll do it. Neat solution. 👍

Yes that is close. But. I can't recommend making that a z bend enough. It's asking to vibrate out. Sorry to sound negative again, but I would not be happy without a locking connection or some sort there. Or make a big hole in the firewall and secure the snake about an inch back? Or a different mount with longer beams? Another tactic I've used is to bring the snake in from below the carb at 45 Deg, that gives more wiggle room for hardware.

That was put down pretty damn hard. Wonder what happened to cause that? I saw a report of strong crosswind, but the descent looked smooth and controlled... apart from being way to steep.

Indeed it does Ernie. The project brief is certainly very open ended. How are you getting on so far Michael? Regarding your research suggestion, I expect you may have noticed by now that early jet aircraft and aerobatic aircraft are very different animals, with very different mission parameters, speed ranges, flight envelope, structures and payloads...

Is there a particular reason you want to run the Veco 19? (rather than, say, a more recent engine)

Looks good. Scratch built airframes are full of these minor engineering challenges - all part of the fun 🙂 Sullivan are 'new ownership' and I'm not sure they produce in much volume, hence the price increases. The Dubro Lazer rods are as good as Sullivan, I think, and about the same price as Sullivan used to be. I can't possibly take credit for the bulkhead thing!

Might be tricky on a Zagi or a. n. other flying wing or weird shape airframe. TBH I doubt that bullet point had as much time applied to it as our two posts have spent discussing it.

is excellent stuff. I only don't buy it as I can't really justify yet more glue on top of cyano and pva!

Jonathan - I'd suggest a bit more foam to surround the battery - at least a complete wrap. Might be my eyes but it looks like the airframe is in direct contact with the cells? In most cases I would put in two light 1/8 or 3/32 formers across the width of the fuselage and just stuff it full of foam with the battery in the middle of it - total overkill? foam weighs next to nothing and there's no danger of the thing coming loose. here you could put two rectangle formers either side of the switch, then stuff that whole switch compartment with foam...

Hello and welcome You said there are 10 people working this project - which aspect of the design are you responsible for? What other design goals does your team have?

Driving itself should take next to no power at all. If it failed from overheating during a zero physical load soak test then you had a lucky escape from flying with it. As for use case, this use case, to me, the thing is just holding position for an hour. Sure, the constant sweep of the position, the motion is artificial but that would highlight poor physical build quality quickly. I've never left them alone for an hour, personally I do use a constant sweep but monitor them for five minutes and then call it done. I do agree that they'll get plenty of time powered up on the bench when setting throws and so on. I've only ever had one or two DOAs and they were HK budget micros, one of which was suffering from a badly formed gear train I think as it sounded awful, the other just instantly smoked. Never had a brand new Hitec, Futaba or JR fail.

Burning-in is a bit of archaic term, but any electromechanical device with make/break contacts (e.g. the motor in the servo, or in other things, relays, switches, etc) has a wear cycle on the contacts to which 'burn in' might be considered applicable. That aside, the bathtub curve is a real thing, and an hour of soak test will give you a high degree of confidence that you have one of two things, (1) a proven bit of kit or (2) melted plastic and wiring.

Second that, it is excellent for both pinned and mylar/polyprop hinges. I tried dismantling a test piece and found the hinge tore apart before the canopy glue let go of the wood. With slot type hinges, you can use a 1" section of drinking straw to 'inject' some glue into the hinge slot, before pushing the hinge into place... those aren't going anywhere when they are dried.

As a couple of asides; Clark Y has 50% more camber than YH (because of that reflex). Some other sections similar to the YH - Naca M6 is very similar with a flat portion to make building easy. http://airfoiltools.com/airfoil/details?airfoil=m6-il TSAGI 12 is similar, slightly less camber, same flat underside. http://airfoiltools.com/airfoil/details?airfoil=tsagi12-il

NACA 2412 or 2415, if you want a model friendly semi-symmetrical. Or... A number of full size from the time used Clark YH which was more "semi-symmetrical" than Clark Y, but still an easy build as it had a flat section. Often full size would thicken it up to 15% (or even more).

you're probably right, the smaller pack will be plenty, and the weight of the pack is more of an issue at this scale. DW's designs were all good, should make a great flyer 🙂

If you're going glow powered it'd be well worth using a servo with rubber bush mounting - not sure many 9g sub micros will have that? The servo will get shaken via airframe and linkage. I use HS81 on most throttle installs as they're the smallest thing I can find with rubber grommets and they all seem to be holding up fine. What about a small lipo for RX power? (I know I'm usually an eneloop advocate, but...) IIRC - noting your other thread - acetate sheeting was 1/32" (ish) or 0.5mm. Or you could slice open an empty 2L Pepsi bottle?

Not especially, but I get why it came across as such. Hope I didn't annoy/offend/upset - that was not the intent. Back on topic... build options look great, should be a lovely project and end result.

I quite agree. Censorship and its use throughout history is a whole different topic...

Simplest engines of the lot. Well made. Run nicely. Start easily. These three have one main needle to adjust... simple. The idle is an air bleed screw, which, give or take, should be set to half way block the hole. It's unlikely to need much adjustment... simple. Couldn't be a better starting point. 40FP would be my suggestion... strong contender for "best glow engine ever".

Just a slight adjustment there... See also, confirmation bias.

I bought my stickers from an ebay seller - don't remember them being very expensive at all. Mine have gone on the underside of the wing (usually). As a bonus, they have a picture of a biplane next to the number.

To anyone fitting two .19s to the original, or .30s to this bigger one, I wish the very best of luck. I'm two twins in and a third (still!) on the board, so I'm not the most experienced in flying twins, but I have some experience - my last post on engine choice on this thread will be drawn from that: Do you want the aircraft to be easy to deal with on one? Or do you want a cut and glide with one out? Critical moment is take off. Anything else you have speed. So. Do you want to be able, if one engine cuts on takeoff, to poke in a dab of rudder and keep it in a shallow climb before making an easy circuit into the landing pattern? Or do you accept you're most likely going straight ahead into whatever happens to be in front of you? Not all of us fly from a straight mile of tarmac with no obstacles. Without enough grunt to keep climbing, I would be straight into a hedge at my site. More power gives you more options. I'll stop polluting the build thread now.

Are you going retracts or fixed? Thinking of adding flaps? I know the small one doesn't have flaps but this looks plenty big enough to carry the extra gear for both flaps and retracts.

The wing area is 850 sq in for the mk2 Duellist (revised plan). That was for 2 x 40s. I make that, 1.16 x 1.16 = 1145 sq in (approx) for this increased version. That's a fair sized wing. On a single engine I'd be thinking 20cc glow or 30cc petrol? Engines go with cubic increase, 1.16 x 1.16 x 1.16 = 1.56, ie 50% larger. Are you sure the two 46s will be enough? (now seems like the right time to ask)