When does a loosely copied design become your own????? - Page 4 - RC Groups
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Dec 02, 2010, 06:10 PM
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It turns out that it wasn't in Air Trails but was in Model Airplane News February, 1945.

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Dec 02, 2010, 09:41 PM
MAAC 6251
Originally Posted by Circlip
Slots are the fixed blades on the leading edge of a wing as in the Feisler storch, Slats are the adjustable blades.

Regards Ian.
I stand corrected. Live and learn. Here from From Wikipedia:
"A leading edge slot is an aerodynamic feature of the wing of some aircraft to reduce the stall speed and promote good low-speed handling qualities. A leading edge slot is a span-wise gap in each wing, allowing air to flow from below the wing to its upper surface. In this manner they allow flight at higher angles of attack and thus reduce the stall speed."

"Slats are aerodynamic surfaces on the leading edge of the wings of fixed-wing aircraft which, when deployed, allow the wing to operate at a higher angle of attack. A higher coefficient of lift is produced as a product of angle of attack and speed, so by deploying slats an aircraft can fly more slowly or take off and land in a shorter distance. They are usually used while landing or performing maneuvers which take the aircraft close to the stall, but are usually retracted in normal flight to minimize drag."

"Automatic - the slat lies flush with the wing leading edge until reduced aerodynamic forces allow it to extend by way of springs when needed.
Fixed - the slat is permanently extended. This is sometimes used on specialist low-speed aircraft (these are referred to as slots) or when simplicity takes precedence over speed.
Powered - the slat extension can be controlled by the pilot. This is commonly used on airliners."
Last edited by RobZ; Dec 02, 2010 at 09:55 PM.
Dec 03, 2010, 03:38 AM
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owlsabie's Avatar
Thanks for the pictures, they have now been saved somewhere in my pc - so it "should extend at least 2 rib spaces", I take it this would be out near the tip? Would spring loaded slats work on an rc plane? I know the Lizzy had flaps and slats working together this way, as did a number of WW2 planes (I think also the me 262 maybe?).

Another thought. Slots could also work quite well to strengthen the wing

Maybe the answer is to just give it a try. . . slots and slats and funny noises could be fun.

Sorry to steal your thread Rick - I promise to leave it alone now!

Last edited by owlsabie; Dec 03, 2010 at 03:50 AM.
Dec 03, 2010, 08:29 AM
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Although I thought I was correct in my own understanding of the terms Rob, I also had a quick Wiki before I posted.

Terms get distorted, how many talk about wing "flaps" when they're really talking about ailing rons??

Regards Ian.
Dec 03, 2010, 10:57 AM
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Well, this may be my take on the whole slat vs slot terminology thing, but, i think you will find that slots are a gap IN the front of an airfoil section - as in the excellent drawring posted by Jim Dean - whereas, slighly differently, slats are an additional thin curved plate supported above the existing airfoil, like as used on my red Red Zephyr and the Storch.

Making slots is tricky because they really have to be designed and built in during construction. Slats on the other hand can be retro fitted to almost any wing that has some Leading Edge sheeting to fix the slats mini pylons onto.

Both work well, but i feel (imo) that slats work better because they actually curve almost parrallel with the front 20-25% of the airfoil and force air to be redirected, whereas slots just kinda bleed high pressure air from under the front of the LE to add to the air travelling over the top. truthfully though i have never tried slots to compare the effectivness. I should imagine that slots add less drag in normal flight since they don't protrude into the airflow like slats do.

Anyway, if you've not tried either, give the (easier to build) slats a go - if you,ve got an old trainer type with a flat bottomed wing, copy my slat design and fit them full span, you'll be amazed at how much more nose up you can cruise past at, during dead slow flybys

final thought - i would NOT recommend making the slat pylons able to retract down into the wing - automatic deploying slats MAY work, but if one slat deployed and the other stayed flush with the wing you'd likely get assymetric drag inducing yaw and also (at high AoA) the possibility of a one wing stall with the other (slatted) side still flying - that COULD induce a difficult to recover from spin. Just stick to the tried and tested fixed slats - its safer

Another edit: yes Owlsabie - it would be possible to design a slat deployment mechinism the operated off a Flap servo, so they all came into operation together, but the mechanics of it would be a work of art or labour of love i guess.

Also: I've uploaded a couple of pics that show the Slats a bit better - zoom in to see the detail. Notice that the front opening of the slat does not go right down to the bottom of the airfoil, it is designed to present maximum front opening to the airflow when the wing is angled up to near maximum AoA, as in slow flight mode. Notice also, the rear opening of the slat is only about 3/4 the size of the front gap- this is to speed up the airflow before ejecting it over the wing.
Last edited by Rick.; Dec 03, 2010 at 12:13 PM.
Dec 04, 2010, 12:44 AM
Sic itur ad Astra
sparks59's Avatar
Hey Rick,
I understand the dilemma you have. For sure, you have built in lots of changes from the original design that can be seen on the photo's when you really look closely. But even so, there is still no mistaking the planes origin of species. Having said that, I think you are entitled to name it whatever you like, its yours after all. Rick's Zephyr would seem to be an appropriate homage to the original. I still think other modellers will ask / comment on the changes so you'll have to explain them anyway, but that's no bad thing I reckon.

just my two 'penneth
Dec 04, 2010, 09:54 AM
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Quite right sparks, i think ' origin of species' is most apt for this - like the way you can see how a chimp could be morphed or evolved into a man, same head, limbs, hands etc - and yet a chimp is clearly not a man.

To be clear - the all red one in the photo, I DO still refer to as a "Red Zephyr Variant". Its the new variant on that - currently under contruction that i have re-named (Mistress Misty), since it doesn't even retain the true RZ tail feathers outline. I also have a little red and white 36" electric one - and in this one i also include the Zephyr name - the Mini e-Zephyr (just posted in the park flyer forum)......

I will always readily acknowlege the Red Zephyr influence in my new planes design, since I am not trying to steal a design in any way - its just that after soooo many mods you can't honestly pretend its the same as the original design - Man or modded Chimp?

Here's a brief run down of the changes (compared to a Red Zephyr original) that will be incorporated into the new design - there will be a few others too:

chord increase 20%, fixed LE slats, 3 spruce spars, wider LE sheeting removeable outer panels (for transport), possibly eliptical outer panels - but in any case no LE sweepback.

Nose reduced in length 10%, wing seat increased 20% (ie chord), tail moment reduced 16%, tailplane seat (chord) reduction 6%, tail section removable, fus max width increased by 20%, angled in nose cowl, reduced u/c track 10%, removable u/c, all wood construction beefed up by 50% plus spruce reinforcements, changed front fuselage construction (thick sheeted area). All cowl and access hatch shapes are different from the original 'natch.

re-profiled tailplane and fin/rudder to my own design, plus totally different internal construction layout from original - (top mounted rudder 'concept' remains from original, but is torque rod operated from below). Tail unit is bolted on - servos in the tail.

Finally, after considering the above modifications, the whole thing is scaled up a further 50%....... 9 foot span, 20cc fourstroke gasser powered.

Conclusion: Is that enough change?????? You will be able to tell she's like a Red Zephyr - but she sure ain't a Red Zephyr now................ she's the 'Mistress Misty'
Last edited by Rick.; Dec 04, 2010 at 10:16 AM.
Dec 04, 2010, 09:43 PM
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skylane42's Avatar
Years ago, when RC Modeler was stillon the racks, I modified a Goldberg 1/2a skylane. I didn`t pretend is was anything but that. I submitted the article and plans to RCM. The wanted a release from Goldberg before they would publish. On another note, just how many "Ugly Sticks" have you seen over the years.
Dec 05, 2010, 03:17 AM
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adamtc's Avatar

From my limited experience of vintage events, if you use the wrong type of rubber bands to hold the wings on, people will not accept it as original.

I think you have done enough design changes to warrant a new name. Using the original name may help pay homage to the basic design. Zephyrella!

Ive just build a Majestic Major with a big old four stroke, servo in the tail, solartex covering and carbon reinforcement. I call it a MM but Im sure the purist would pour scorn on that.
Dec 05, 2010, 08:26 PM
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skylane and adam - yep. i agree, a few mods to a design don't warrant a new design name, but its a question of degree i think. true for example there have been scores of Ugly Stick variants, but they keep to more or less the right proportions, mostly just a size change. I mean......how about if i do away with the RZ type 3 panel wing a go for a normal vee dihedral or even, a straight wing with ailerons? what if i then choose to put a steep curved waist in the fuse tapering to a thin section at the tail - is it a Red zephyr then??? Tricycle undercarriage? square tail feathers??? How far can you go and still have to say its only a modified RZ design. Look at it another way guys - if i drew up the plans absolutely from scratch - what i would get, what i would like, is the design i've got now for the Mistress Misty (aka Red Zephyr variant).

i guess, the reason i'm trying to kinda justify a new name, is that whilst I know shes a very different beast from any kind of existing RZ, i worry that some others won't see it that way and think i'm just stealing a design - which is not my intention. its not fair to the original RZ design, to say mines just a bigger one. Neither would it be fair to me to sweep away all my own constructions and profiles as simply 'mods'. And yet, the most attractive features of a RZ (3 panel tapered tip wing, cabin design and jutting u/c) are essentially still visable in mine.

Thought: what would happen if you took say three cabin design old timers measured ALL of the vital statistics, angles, thicknesses etc and averaged all measurements between the three, transferring them to a new design - what would you call that, without offending anyone?????? have i persuaded you to see it differently, or myself?
I know some would ask 'does it even matter?'
Food for thought then.............
Dec 06, 2010, 04:40 AM
Sic itur ad Astra
sparks59's Avatar
I agree with all the comments guys.

The proof of the pudding, as they say, is in the eating. See how it looks when it's finished Rick. As I said before, I think that you are entitled to call it your own with all the changes you have made, but, depending on the amount of (sort of) unique design features you incorporate, will, I think, be the decider for comments from people who may be trying to identify it.

If you, for example change the span and chord of the wing, lengthen the fuse a little and change the rudder contruction you may have had to do a fair amount of redraw, but most likely the finished plane will look more or less like the original. But, if you, for example replace a polyhedral wing with a dihedral design, change the fuse shape and method of construction, and change the t/p from rounded to a squared off design, the result would be unlikely recognised as the design you may have started with.

That being said, the limitations and existing variety of 'cabin' designs would probably mean it would look a bit like another, different, design altogether ;-)

Last edited by sparks59; Dec 06, 2010 at 04:41 AM. Reason: dyslexic fingers
Dec 06, 2010, 02:44 PM
Registered User
Originally Posted by Rick.

Thought: what would happen if you took say three cabin design old timers measured ALL of the vital statistics, angles, thicknesses etc and averaged all measurements between the three, transferring them to a new design - what would you call that, without offending anyone?????? have i persuaded you to see it differently, or myself?
I know some would ask 'does it even matter?'
Food for thought then.............

I would call it "Edna Average"
Dec 06, 2010, 06:53 PM
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Lol, yeah john, nice one. Seriously, for those gloomy winter evenings with little else R/C wise to occupy the time, such an excercise could be quite fun - ya know, wondering what'll come out of it. And what'll you name it (junior bomber cub house etc)

Ah, but then, in Oz, while i got a gloomy winter, you got summer!

As a matter of interest i have been looking at loads of designs that could be said to be similar to my version of the Red Zephyr. I came accross a 1930's design called the "Miss America" which has been modeled by many.
Well, apart from a deeper tailpost, different windows and a longer nose on mine, you could say that my fuselage version is as much like a modded "Miss America" as it is like a modded Red Zephyr......... (to be clear, i'm only considering the fuselage profiles here, the tail feathers are very different).

So, could my big RZ variant be as much a big MA variant? or maybe partialy so? Kinda makes a nonsense of the whole "whose design is it anyway"? issue.

I'm thinking now, maybe i'll make some sweeping changes to my fus profile and its constructions, then its got to be my design - hasn't it???
Last edited by Rick.; Dec 06, 2010 at 10:16 PM.

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