Syma Forum

SF, CPD, and all,

Test flights continue.  Trimming getting better.

Pics - One is the duct looking edge on.  Second is view of one duct from the top.

Haven't gotten flight time figured out yet. (Dang watch battery is croaking! Jumps 15 seconds at a whack.) [Have to get battery replaced.]

Definite difference in flight characteristics.

Regards, Sarge

All,

I'll add that test flights have been restricted to indoors!  It is 28 F outside with 28 MPH gusts.  Wind chill @ 16 F.

Tests have been indoors and no higher than my waist.  I wish it would settle down to take it outside!  Not enough room indoors to do the tests justice.

I not only want to get the trim dialed in, I want to see if this can give extended flight time.  This would give a good indication of airflow improvements.

Regards, Sarge

Yikes! Been there before, where you think that you're ready to go, and whoops! It done goofed! I think the worst was the RC car that I tried to make amphibious, before the silicone I used to seal the motherboard gave out and let it get flooded. No idea what happened to make it stop working for no apparent reason after I had replaced it, and I haven't gotten around to fixing it. I think it needs brought back to stock to save it.

So far so good with the ducts!  I've just got to finish the last duct.  It is actually going easier than I though it would.

I couldn't resist "semi decent" weather.  I just had to take the other one outside.  I had the wind get hold of it and had to jump into the wheels and go chase after it.  Then like a dummy, I had left the controller on with elevation engaged.  It leaped up into the air.  I had to chase it a little bit, and ended up landing on someones SUV.

Nobody squawked, and no damage was done.

I've just come in after going through three battery packs.  Gave the rubbish pickup folks a couple of buzzes.  Got them interested in where could they get one, and did it do more than hover.

So I did several 3D Eversions left, right, forward, and back.  That left them with jaws dropped open.

I needed a "fix" of flying!  Get tired of working on one and needed a break.

I've got the ducts notched to allow the motor unit spars to clear them.  It looks like the weight won't be excessive.  I'll weigh the both of them on a good little scale I've got.  Then I'll hace a better idea.

Regards, Sarge

That isn't necessarily true.

Do some research into the first "gull winged" "half ducted full scale aircraft.

Then there are ducted fan jet engines.  Very close isn't required.  Simply ducting within a small portion of the blades is all that is necessary.

Look at the Aerospatiale Helicopters tail rotors.

Ducting of rotors, whether they are propellers or rotor blades, works to increase the air flow.  These Quad Copters are nothing more than propellers.  Any form of duct will improve the lift characteristics.  Similarly Fowler flaps increase the lift by essentially altering the effective wing chord.  Yet close and tight aren't necessary.

Even if there is a 3/8" gap, the flow will be improved.

Regards, Sarge (Certificated Pilot - Mainly aerobatic, and a pilot of a Sukhoi SU-29.)

Hmmm... Seems that something to fix that is in order. When I was a kid and had a styrofoam Air Hogs R/C airplane, what I did to fix where it got banged up was covered the beat up spots in invisible tape, just like I do with my helis blades. That stuff isn't as cheap as it used to be--they want a whopping dollar for useless tape that should cost fifty cents!!! But, that seems to cover up dings and dents pretty well, while giving it a nice support along its outer fiber. I would personally worry about hot glue because it would be hot enough, I would think, to melt the foam itself, and it's sorta heavy when compared to this. Then again, it's not ideal to have an expensive toy like the X6 and have it held together with scotch tape.

Actually, thinking about it, what about foam. Not like styrofoam, regular high density foam? Like what you buy for the bottom layer of foam when reupholstering a chair. That stuff can just be cut with a knife, glued together, glued to the frame, weighs nothing, is pretty cheap and can be found at any Jo-Ann's Fabrics. Again, though, the problem would be re-enforcement, but if you add a small basswood (I wouldn't use balsa there because it's not strong enough) subframe under it, then it'd be perfect!

I hear you with how there isn't a hobby shop to buy stuff from--been about ten years since mine closed up, and I have yet to find another that isn't in poor shape. Found one last year near my college, but it was just sad to walk into. The old boy running it had basically given up 15+ years ago, and was barely keeping the lights on selling, or rather stocking since he wasn't selling very much, doll making stuff from the late 80's or the early 90's. I was probably his only customer that week.

When I bought my styrene, I bought it online. I forget the name of it, but there's a hobby shop down in Georgia, I think Atlanta, if it is Georgia, with a really nice website with a great selection and good pricing on stuff. I'm looking on Amazon at the moment, and they have it, but it's not prime, although a pack of 7 sheets, .02" thick costs $10 with free shipping. ie=UTF8&qid=1420727464&sr=1-22&keywords=polystyrene+sheet

If you can find it, there's also almost every possible structural member used in the real world made from the stuff. Pipes, rods, angle iron in MANY sized and combinations of one side being this size while the other is another, I-beams, double-I-beams, box girders, ladders, clear, tinted, corrugated tin in multiple scales, wood siding in multiple scales, railroad coach siding in multiple scales, asphalt shingles, ceder shingles with a pattern, slate shingles, etc. If somebody really wants to, they could use this stuff and some serious skills to make a steampunk S107 that looks like a steam locomotive and has the proper rivets and wood siding for the side frames if they so well choose.

I should note that I was considering doing something like this, with attaching polystyrene to the ducts on my X3 to extend them high enough to actually be effective. However, I decided not to, because of how they are designed to flex upon impact. Either I would have to add a bunch of weight and have them be solid, and not be able to take hits as well and keep flying, or the ducts would ram into the blades and ruin both of them when it crashed. I think that is the reason that the ducts on the X3 are so short, and why they may not have them on the other helis. However you decide to make yours, they need to be rigid so that they don't interfere with the blades if you crash.

SF,

So am I.  I will say that it won't be quick though.  I'm going to have to build a form, then add the radius to the form.  It will be a PIA.  The temps and weather won't make up its mind either.  I can't keep up with 20s F, wind blowing insanely, 60s F and soaking rain, and who knows what is coming next. Plays holy devil with my bloody Arthritis too!  When the entire spinal column hurts like the devil, you don't really get in the mood to "work" on anything.  I detest taking pain meds, but there are times when it finally get to that point.

The final form will have to be coated with something  such as an oil based varnish, (If it can even be purchased any longer), or a couple coats of Tung oil. Then the patience factor gets in the way waiting for this *one* darn form to dry thoroughly.  Then the paper has to be laid on the form while wet to take the proper shape.  Then repeat three more paper lays on the same form after each one dries.

By that time I'll be ready for my favorite beverage.  (Single malt Scotch please! - Or Bellarus Vodka! [Man is that ever so smooth! Not like almost any other Vodka that is like diesel fuel!])  I'll deserve it by then.

I think I'll use some artist acid free paper.  It is thicker, and will be more durable when it sets.  The additonal weight won't be worth considering with the extra airflow.  I haven't exactly worked out the adhesive on the form - or for that matter exactly how to apply it to the frame.

I've tried to do "some" work on the Slicktron PCB and motor units.  I'm just at the point where the motor units are ready to be soldered.  It is going to be a "guess what it will do" job. 

Regards