Here is a list of all the postings Down Under has made in our forums. Click on a thread name to jump to the thread.
|Thread: Thermalling clockwise or anti clockwise?|
For once I can actually make a useful contribution here. I used to fly paragliders, and we were always looking for those elusive thermals. In fact, the duration of our flights were often deteremined by how well we could read the country side for thermal trigger points.
The fact is, most thermals do not rotate clock wise or anti clockwise. Picture a column of air. Warm air rises up through the middle (thermal) and descends down the outside of the column (down draught) as cool air. To enter the thermal, you first have to pass through the descending air on the outside of the column before you get to the thermal inside.
A good indicator that we had found a thermal was either side of the wing lifting. The same applies for paragliders and models alike. Here are a couple of scenarios:
1) You manage to enter the thermal dead centre. In a paraglider the wing would remain stable, but you would feel a descending / falling sensation, followed by a sudden and some times violent ascent as you hit the middle of the thermal. Our vario (flight computer) tells us when we have past through the strongest part of the thermal, at which point we then make a decision as to which way to turn. If you are first into the thermal, the choice is yours, otherwise you follow the same direction as every body else.
With a model, looking up from the ground, it would be harder to tell that you have passed into a thermal as you have neither the sensation nor the flight computer telling you. The biggest / most visual sign will be the wings of the glider rocking as it passes into the middle of the thermal. Wait a couple of seconds, then begin coring the thermal (circling in the thermal). I guess same ettiquette applies. If you model is alone or you are first to enter the thermal, circling direction is up to you.
2) You enter the thermal offset or to the side. This is easier to see from the ground that you have found a thermal but needs to be treated differently. Again, the same applies to paraglider as to a model. Lets say you find a thermal and pass throught it on its right. Your inside wing (left wing) will lift as it catches the thermal while the right wing will fall as it stays in the down draught. This has the affect of turning the paraglider / model OUT of the thermal.
Most people would naturally try and turn the paraglider / model left back into the thermal. While strictly speaking there is nothing wrong with this, you actually lose forward momentum / speed as you are fighting forces trying to turn you out of the thermal. The more efficient approach is to let the paraglider / model follow its path out to the right and because you are not fighting the natural forces already being exerted on the aircraft, you will actually maintain or gain forward momentum which you can use to your advantage. As the paraglider / model is pushed out to the right (with the left wing being lifted), you are better to follow through and circle round to the right, as you come back round let the model straighten up so you can enter the thermal with some speed. The idea of speed here is to pass as quickly as possible through the down draught and minimise your height loss. So your circle to the right becomes elliptical as you come around and re-enter the thermal. (Would be so much easier to draw a diagram, but I hope you get the picture).
Of course, if you passed a thermal on its left, then opposite would apply.
In short Bruce, there is no 'correct' direction determined by the air. Only the direction called by you. If you are first in, or alone, the choice is yours. If you are second or joing a group, the correct direction has already been pre-determined and is best followed in the interest of avoiding a mid-air...
Hope this helps.
Edited By Down Under on 30/08/2013 13:09:47
|Thread: Ebay sellers...|
Shame. Would have been a lovely little plane it its time.
But for its price, 75pounds, I'm sure half the nuts on e-bay are smoking crack!
|Thread: Ben Buckle Online Store|
Nope. Nothing about 30th August. Only:
"Will usually post within 3 working days of payment..."
I bought and paid for a meter (3ft) of window glazing from Ben Buckle online e-Bay store, (for my Pix E Major that is progressing slowly). The site says to allow 2-3 days business for despatch.
I paid for it a week ok, and today it has still not been marked as posted. I am hoping it has been posted and the item has just not been updated on e-Bay.
I have tried contacting the seller, but no repsonse. He has a "gold medallion" for sales according to his profile and 100% postive feed back rating.
I have literally spent thousands of dollars on line spanning the last 8 years and never had a bad experiance. I am hoping this will not be my first.
Has anybody else bought from the Ben Buckle online e-bay store?
What has been your experiance?
Thanks, Down Under
|Thread: new Hobbyking site|
I for one shop at HK with the knowledge that it can be a hit and miss affair, but so far I have had no misses.
That been said, many of the motors and esc's are priced such that they are 1/3rd the price of my LHS. Sure the quality might be 1/3rd that available in the LHS, but if I buy 3 motors or ESC's and one gives out, they way I figure it, I'm still ahead.
People who continue to shop at HK with high expectations are leaving the door open for possible dissapointment.
Look at this way, if HK stuff was so rubbish, and they only received complaints, they would have been out of business by now. The reallity, for every one compliment, you will hear 5 complaints (made up statistic but you get my drift). We tend to only see the complaints. What about the 1'000's of statisfied customers you don't see!
Sorry Paul, but I agree with Pete about sweeping statements...
|Thread: Losing patience with HobbyKing|
This is. Not the first story I have read/ heard about HK service along these lines.
i have bought many an item from HK without issue, and when I do, I tend to pay and forget. Then if it takes 3 weeks to arrive its a pleasant surprise when I least expect it. So far everything has turned up. I am looking to spend a couple hundred bucks next on a car which I hope arrives in one peace.
Personally I work with one rule. Never buy anything on line you can't afford to lose or take a risk on. This has stood me in good stead so far. If its that expensive, I would rather go to a local shop front where I can have face to face interaction and some where to go back to in the event of product failure.
|Thread: Learning to fly|
How AWESOME is that! I think that was TERRIFIC!
I am sure he went home with a grin from ear to ear.
What a great way to hook in the public and help grow the hobby.
|Thread: super slinky build|
Hi Chris, love how you work.
Hmmmm, need a few spruce spars . No problems, will just whip a couple through the bandsaw then the thicknesser. 16 ribs? No problems, where's that planer? Hahaha!
Where would we be without these modern conveniences?!
llooking good so far ; )
|Thread: Trainer reviews - who should do them?|
I for one think this is a great idea. Especially giving a beginners kit to a beginner to build and report on. I guess the challenge / risk is finding some one who will document sufficiently their progress such that a decent article can be written for the magazine.
|Thread: Glo Pro vs Electric Prop|
Hi Erfolg & Pat
I did not expect my query to expand into a full blow debate, but I thank you for your input and have read both your points of view with interest.
To be honest, all I am looking for is a powertrain to get me up to altitude in a reasonably short space of time so I can do some thermal hunting or enjoy the glide back down. My own humble opion, any design still selling after 30 years must be ok.
As mentioned, she is no competition ship, but all I am looking for is some lazy flying on a sunny Sunday afternoon down at the local footy oval or school field. I think she will be just right for me.
While I am learning and embracing the world of electrickery, I do wish it was as simple as IC where an 0.049 is an 0.049, a 0.25 is a 0.25, and a 0.46 is a 0.46.
Thanks everybody for your replies.
I was deliberate in keeping my posting brief as I was hoping there might be a simple co-efficient or conversion factor that I coud use, changing from a rigid to a folding prop. This does not appear to be the case.
The glider in question is the classic Carl Goldberg Gentle Lady. 72" wingspan. I use to own one about 20 years ago which used a TD 0.051 and a 6 x 4 prop to get her up. As yet, had not decided on pylon or nose mounted motor, but probably leaning to nose mounted. While a vertical climb out to altitude would be most amusing, I'm not sure that she was designed with that sort of performance in mind. I had thought around 150W - 200W / lb might be the go.
As Pat pointed out, a pylon mount would limit the size prop which is also partly why I am leaning towards a nose mount. I have limited knowledge around motor / esc / lipo combo's, enough to get by. My uncertainty was mostly around the propeller size and the effect of losing length to the diameter of the spinnner.
Ideally I would like enough power to climbout at around 45 degrees to altitude, then switch off and glide back down, or hunt for thermals. There are no usable hills nearby so really it will just be some flat fland flying.
After all is said and done, if anybody can suggest a tried and proven combo that would provide for a spritely climb, I would appreciate it...
Hoping one of you knowledgeable folk can enlighten me.
I have a 2 meter glider which calls for a 0.49 - 0.51 motor (optional) for assisted launch. Prop size approx. 6 x 4.
I want to use an electric motor instead, equivalent power output, but also want to use a folding prop to reduce drag. If I use a 6 x 4 folding prop, I effectively lose 2 to 2.5" in overall prop length to the diameter of the spinner. I assume this will reduce the overall efficiency of the propeller. Granted, folding props tend to be wider.
Do I need to use a longer prop / spinner combo (say 9 x 4 to make up for the prop length lost by the spinner)?
Any guidance or words of widom would be greatfully received.
|Thread: Plans Wanted - Sig Rascal (any size)|
Thanks Jrman. Looks like I will have to buy from other side of the world. Does not appear to be any distributors in Oz.
|Thread: Those were the days|
Watching those clips put a real smile on my face.
I just couldn't see those free flight competitions happening these days. The Occupational Health & Saftey chiefs would have an absolute field day. Uncontrolled aircraft with props spinning at 10'000 RPM turning down wind and heading straight for the spectators...!
|Thread: Plans Wanted - Sig Rascal (any size)|
Does anybody have any plans for the Sig Rascal? Or know where I could get them? Any size will do.
I have scoured the web, and they seem to be very elusive (or else I am looking in the wrong place).
Thanks in advance
|Thread: balsa stripper|
I have the Master Airscrew one (the little black one). Basic, and very easy to use. Cheap too. Had mine for about 20 years and still going strong. I'm sure the SLEC one is just as good though.
|Thread: Kits and Plans|
I am in the process of building the Pix-E major. Just have the wings to do. While it looks like a great plane, it is a very delicate structure which is likely to be destroyed in a crash (IMO). I will finish it soon, but leave it until I am more confident in my flying ability before I take it out. In the designer's own words, not really one for beginners.
I have built many models over the years, but ironically am still very much learning to fly. The first kit plane I bought was a Gentle Lady (about 21 years ago) and was a beautiful and well mannered glider to fly. Very forgiving. I also found the kit to be pretty straight forward. At the time I had very little building experiance, but came out quite well (if I have to say so myself). To that end, I have just bought another kit from Tower Hobbies (more out of nostolagia than anything) with the intent of putting an electric motor up front. I would highly recommend this kit as a beginners build. Slab sided fuselage and straight forward build.
Another plane I have built is an Airtronics Q-Tee which I built from scratch and swapped the 0.049 for an electric motor equivalent. Very cheap to build, fairly rugged, and easy to repair in a crash (believe me, I know)! When trimmed properly, she is really easy to fly and can be flow relatively slowly. Slab sided fuselage and constant chord wing. Very easy and quick build. I have been teaching myself to fly on this model with confidence I could repair it myself, and the total $$ outlay was modest. I would also recomment this plan / kit.
I have the Q-Tee PDF file which you can print off at home on A4 paper as a set of tiles and tape it together. Let me know if you would like me to send you the file.
|Thread: Lazy Bee as a Trainer?|
Thanks for taking the time to share your points of view. While I hate to admit it (purely because I am not a fan of foamies), I think Ruprect is probably right. Think I will invest in a foamy to learn on, and save my precious balsa models for later.
Still, the Lazy Bee looks like a lot of fun to entertain the kids at the local footy oval. Will have to add to my looooooong build list!
Thanks again to everybody for sharing your valued points of view.
Hi All, to any and all Lazy Bee'ers out there, could a 48" (or there abouts) size Lazy Bee be used for learning on?
Edited By Pete B - Moderator on 14/04/2013 13:55:51
|Thread: traditional build but not vintage|
What about a scratch build? There is a plethora of plans between the RCME plan index, the Outerzone website, and Model Airplane plans site (US site). Parts are cheap between Hobby King or your LHS. The only real price part is the covering, but should still come in under the cost of an ARTF. And the satisification of flying your own scratch build is second to none!
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