hi phil.

hey im just an idiot that has read a copple of books,done a few small samples and made some parts that have never been tested or flown.

stifer spring,lighter spring..higher frequncy ,lower frequncy..matters not...the standard dragon may still have a surprize that we have not met yet.however we call it a known..the modified wing you are conseeving is un known.

if you are going to build a carbon d scin..id say first dont...second make it heavy.
if you are going to build carbon ribs/flaperons..id say first dont..second do not make them hevier

with the droge...your hanglider senses a change in airspeed and dips its nose.

in relation to the dragon diving away from cloud suck or some similar situation..i think we both agree the droge is going to come in handy and it is the lightest air brake for our weight ristricted aircraft..

russ.


On Wed, Mar 21, 2012 at 2:28 AM, Kenny Andersen <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


I'll make some more comments tomorrow, but I got to get to bed here. The thing I don't think Russ is seeing quite yet is that if you orient the LE skins to 45 degrees they will be WAY stiffer than the plywood wing, which means that the flutter frequency will go up, not down. So, no worries there (at least less than a CDI!)


--- On Tue, 3/20/12, Philip Lardner <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


From: Philip Lardner <This email address is being protected from spambots. You need JavaScript enabled to view it.>

Subject: RE: [Carbondragonbuildersandpilots] Re: CDII -fuselage
To: This email address is being protected from spambots. You need JavaScript enabled to view it.

Date: Tuesday, March 20, 2012, 9:50 AM






Hay ho...

My experience is in flying hang gliders, where it is common practice to deploy a drogue when landing in a small field. In normal flight the drogue does not restrict your airspeed in any way - if it did, we'd stall into the ground - it steepens your glide angle by increasing your drag - and 10 out of 10, the drag function is the square of the speed. HGs fly at around 20-22mph on finals and stall at around 17mph - even a small change in airspeed would be bad.

Your example, below, of two dragons flying nose straight down is nonsensical. With your nose pointing straight down you can no longer control/increase your airspeed any further and your drogue simply becomes a very small parachute providing the maximum drag it is capable of - something to adorn a Darwin award. That is not the function of a drogue - that is the function of a parachute - their applications are entirely different.

On the rib weights - w.a.i.t. a.n.d. s.e.e. - patients Grasshopper - those figures are coming!

On the 'springy' carbon D-skin - I don't have a sample of 1/32" ply to hand but I do have a number of largish pieces of 2-layer CF Twill laminate and it is very stiff indeed! If I get my hands on some I will be able to compare it to the CF laminate and physically test it on a shear-load test rig I have made and get some hard data. Then perhaps we can put this sorry topic to bed.

Phil.

---

From: This email address is being protected from spambots. You need JavaScript enabled to view it. [This email address is being protected from spambots. You need JavaScript enabled to view it.] On Behalf Of russell wilson
Sent: 20 March 2012 13:26
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage




hi phil......the context of our conversation was escaping form a cant get down situation..if you are going to escape a situation like cloud suck then you are going to point the nose down before you end up in the cloud..you are going to be going faster than walking pace......your going to do mainly ridge soaring..yer?when a warm front surprizes you and you start going back wards you are going to have to dive faster than walking pace.

a deployed droge will suply a drag force to the square of the air speed.ie at 20 knots it will suply x force....at 40 knots it will suply 4 times the force of x....you are correct it does not slow the aircraft,it limits its speed.but if the aircraft is already beyond the speed that the droge will alow it to exeed and then the droge is deployed..the droge will slow the aircraft.



try this in your head..2 dragons..1 with droge deployed..1 with out...a race from 3 thousand foot..nose straight down..first to the ground?..the dragon with out the droge?..yer?..if thats your answer then the droged dragon had a slower sink rate and a slower air speed.


if the aircraft is in the dive with out the droge deployed and the aircraft encounters flutter
"i wonder if a droge would slow the aircraft enough to stop flutter?"

the dragon is on the limit of 70kg..it does not need stronger ribs..it can not take hevier ribs and stay legal or safe...if your ribs are not the same weight or lighter then you have not finished..you do not want extra weight at the back of the wing or flaperon.

if you build a springy d skin and weight the back of the wing...what do you think will happen?

russ.



On Tue, Mar 20, 2012 at 8:20 PM, KarlS <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


I know you gentlemen are thinking of the 2 part wing with a center box but I would once again like to mention a 3 part perhaps folding wing.

Once again a 3 part wing eliminates the heavy most likely to fail highest stress part of the airframe as per Dieter Reich. I bet Ruppert wishes they stayed with the 3 part wing like their prototype.

Here's a photo for thought.

groups.yahoo.com/group/Carbondragonbuild...inal&start=1&dir=asc

Here's the spin characterists for the Arc and also the highest stress area failing.



Now that we are in the early stages of design concept I am putting the 3 piece wing up again for discussion.

Rupperts original 3 piece wing.

vimeo.com/29536897

Regards,

Karl

--- In This email address is being protected from spambots. You need JavaScript enabled to view it., Kenny Andersen wrote:
>
> @ russI was thinking that most spins were initiated by a stall, but I'm sure there are other ways of getting from here to there. Â Being a novice, I was hoping for something that had pretty docile handling -- it sound like the CD is pretty well behaved -- I'm in no hurry to auger in.
> Clipping the wings reduces the stress a bit, but really considering how strong the graphite rods are it really doesn't take much [weight] to increase the load carrying capacity of the current wing.  Keep in mind the area out near the tip is not so big, so though it does contribute to the moment at the root, it isn't a big weight driver.  I favor keeping [at least] the current wing area (if not kicking it up a notch when thinking motor-glider) because I like the low wing loading. Additionally, a couple of small (right-sized) winglets would probably be useful from what I'm reading.
> @PhilAre you lighter on the ribs than those in the rib article that is posted in the files section?  I'm still in the process of acquiring the software, so I haven't started fiddling with it, but there are a lot of ways of slicing that pie.  The foam is really tempting since it's both cheap and easy to work (hot-wire).  I'll try and post a hand-sketch sometime this week (remember I'm no designer, so...  but I can sketch.  I was thinking that the 'box' would stay connected to the tail, but the pod and wings could disconnect.  I think that way there would be less hassles with the controls. Unless you really have a need to break it way down, it would be even better to leave the pod/sling/cradle (or whatever it ends up being) attached.  In the latter case all of the controls would stay put.  This would greatly simplify the design.
> Kenny
> --- On Mon, 3/19/12, Philip Lardner <philiplardner@...> wrote:
>
> From: Philip Lardner <philiplardner@...>


> Subject: RE: [Carbondragonbuildersandpilots] Re: CDII -fuselage
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Date: Monday, March 19, 2012, 6:39 AM
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

> Â

>
>
>
>
>
>
>
>
>
>
>
>
> Rick has offered to weigh a few spruce/ply ribs for
> comparison, but I *think* I'm winning on the weights.

> Â

> Indeed, lots of cables and pullys inside the tail-boom -
> that's why I'm thinking of housing the drogue and lines inside their own tube
> within the tail-boom. The two control lines (for deployment and
> retraction/adjustment) would need to be run separately rom the rudder lines and
> must not be able to foul them. Perhaps run those lines inside 0.5mm wall
> diameter CF tubes the length of the tail-boom - I have a sample and it's like a
> very stiff drinking straw!

> Â

> I read a report about flying the CD in light wave conditions
> (the Kitplanes Mag article?) where the pilot couldn't get down until some hours
> after dark! I think a big-ass adjustable drogue might save others from a similar
> brown-trouser experience!

> Â
> Phil.

>
>
>
> From:
> This email address is being protected from spambots. You need JavaScript enabled to view it.
> [This email address is being protected from spambots. You need JavaScript enabled to view it.] On Behalf Of
> russell wilson
> Sent: 19 March 2012 11:23
> To:
> This email address is being protected from spambots. You need JavaScript enabled to view it.
> Subject: Re:
> [Carbondragonbuildersandpilots] Re: CDII -fuselage
>
>

> Â

>
>
> hi phill shortening the wings reduces stress....did you make lighter
> stronger ribs?....having a droge deployable and retractable so you can adjust
> your glide path sounds easy...its not....theres not much room in the end of the

> boom and there are controll cables and pullie there to get tangled..i think

> in reality the droge would be a one shot with an emergency release if things go
> bad or acidental deploymant.
> russ.
>
>

> On Mon, Mar 19, 2012 at 9:50 PM, Philip Lardner <philiplardner@...>
> wrote:
>
>
> Â

>
>
>
>
> Russ - download
> my wing & rib stress analysis spreadsheet and plug in the pilot weight and

> other parameters you want to use - it will give you the loadings on the

> spar along the wing at each rib and the loadings on each rib itself. The
> carbon/foam root rib prototypes that I made and tested all survived loads in
> excess of 35kg - over 8g at my desired max payload weight of 260lbs=118kg (of
> which, max pilot weight=176lbs=80kg.) I don't see that shortening the wings
> will allow you to increase the pilot weight - where did that come
> from?!

> Â

> Kenny - I'm
> looking into clear Mylar wing coverings. The prototype Swift was fully covered
> in this stuff and it looked great! Mylar film also has the benefit that it is
> a much smoother surface than any fabric and does not need to be doped or
> treated with any finishing paint to give it a high-gloss finish, as Steke
> Arndt had to do with his Magic Dragon - he used a two part epoxy paint (I
> think) called "Super Flight" which added several pounds weight to his dlider.

> Mind you... it did look great!
> Â

> Like you, I'm
> just beginning to sketch out ideas and drawings for a centre section that the
> wings, tail-boom, pilot pod and landing wheel will all be attached to. I want

> to be able to detach the tail boom from the pilot pod. (I also want

> to be able to detach the tail/rudder from the tail-boom. for more compact

> storage/transport.)Â Almost everything else fore and aft of the pilot

> attachment point is just faring that takes very little load - with the
> exception of the rudder peddles and the nose skid. I'm also considering the
> possibility of removing the rudder peddles altogether and replace them with a
> left-hand control stick that would remove the need for cross-linking the
> controls during foot-launch and foot-landing (no, I haven't abandoned that
> goal... especially after looking at both Swift and Archaeopteryx videos!) No
> rudder peddles = more control and possibly less weight. That just leaved the
> one hard-point required at the front of the pod - the nose skid / tow
> release.

> Â

> Russ - The drogue
> 'chute idea is good, and one I've been considering for a while. I reckon it

> should be possible to deploy and retract an adjustable drogue from a

> small tube at the aft end of the tail-boom. If you use a Pull-Down Apex (PDA)
> style drogue 'chute with a centre line, the pilot could easily adjust the
> amount of drag it produces by pulling or letting out the centre line. By
> pulling the centre line in all the way, you can effectively turn the drogue
> 'chute inside-out and reduce the drag to its minimum. Let it out all the way
> for maximum drag. The 'chute could be retracted by continuing to pull in on
> the centre line until it is pulled all the way back into its storage tube in
> the tail-boom. Just ideas for now.

> Â
> Phil.

>
>
>
> From: This email address is being protected from spambots. You need JavaScript enabled to view it. [This email address is being protected from spambots. You need JavaScript enabled to view it.] On Behalf
> Of russell wilson
> Sent: 19 March 2012 09:27
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
>
>
> Subject: Re: [Carbondragonbuildersandpilots] Re: CDII
> -fuselage
>
>
>
>

> Â
>
>
> tryangular tail boom resists spin(when it points down)Â ,not

> stall.
> the dragon will stall but it is very very forgiving,there is no
> problem.
> a hang glider is a lot of fun,any flyte experiance would be
> good...remember though the controlls are reversed on a hang glider.consider
> going to a gliding club and doing the training sylibus...or fly a
> paraglider..the paraglider is cheep and it wont train your muscles to slam a
> sailplane into the ground on landing.you can travel with it too and you will

> get moor hours than other types.there will be flyte training were you
> are.
> Â

> i comend you looking for a solution ...a solution to get a hevier pilot
> into a dragon.

> your field of experteese is right in line with helping to finding
> the extra strenth or less stress configeration needed to fit maby
> a 90kg pilot into a dragon..who knows maybe even 100kg pilot.
> Â
> Â

> if you want to do something real something practical something that will

> work and perhaps be used, then tell us how much we have to cut of the

> tips of the wings in order for the dragon to carry a 90kg person safely..then
> follow the load path and tell us if the rest of the sructure will hold.

> Â
> russ.
> Â
>
>
> Â
> On Mon, Mar 19, 2012 at 5:38 PM, Kenny Andersen <kennyrayandersen@...> wrote:
>
>
> Â
>
>
>
> I didn’t say I wasn’t going to build, I said I wasn’t planning on
> building any time soon. It’s mostly because I’m not even in the country, and

> secondly because I have a couple of projects lined up ahead of this one. I

> don’t regularly fly, but I took a few lessons in High school and really
> enjoyed it. My family didn’t really have the money for me to pursue it, so
> it’s been on the back burner for years. Now that I’m older and more
> financially established and the kids have all moved out, I’m able to make
> some things happen that I’ve wanted for a long time. Last year I bought a
> FIAT 500 out of the UK â€" I’d wanted one for 30 years, and I finally got it â€"
> an original D with suicide doors! I’ve wanted to build a three-wheeler for a

> long time and will likely order a Triking in kit form, again out of the UK

> (why do they seem to have all of the fun stuff going on!). Then I’d like to

> build a sailplane or a Lotus 7 clone
> (probably a Birkin). Just because

> I’m not doing something for a while doesn’t mean I’m not interested or not
> willing to help â€" I’ll reap the benefit later on when there is a CD that

> will work for us guys that are a bit heavier. I think the weight issue alone
> has kept a lot of people from perusing it more seriously and I think George
> also has a point that getting some basic tooling up would be a godsend. The

> time and effort factor has certainly scared a lot of folk off. Whether he’s
> willing to do that I can’t say, but I’m thinking of someone made a D-Tube
> (or at least the skins and spar) and a boom most of the other stuff wouldn’t

> be so bad. My buddy Mark developed all the tooling for his Robin, and we put

> together a few ideas to make it go together a bit less painfully, but it’s

> still a LOT of work.
>
> I love building stuff and have worked in stone,
> wood, metal and also paint and carve. I also do stained glass and make
> jewelry. As an accomplished amateur wood and metal worker for more than 30
> years, I have no doubt in my mind I can do this as well. As far as the day

> job I’ve been analyzing composite and metallic structures for 27 years. Most
> of that has been with big companies, so I’ ma bit specialized. I hope to get

> some more broad-based experience looking at the CDII. Usually, my job is
> limited to configuration and sizing optimization, whereas for this effort,
> there will need to be more design integration, some load development and
> also some materials testing (which I have done a bit of and am actually
> doing right now on an Air Bus program). I get paid some kind of ridiculous

> amounts as a consultant, but since I’m interested in doing a CDII, I figure
> hobby time is free. I’m not looking for anything monetarily out of it, just
> the fun of
> doing it. Frankly, there isn’t enough money in it to interest
> me professionally â€" I can make way more as a consultant. When we’re done

> sizing everything if someone wants to put together some drawing and sell

> them I don’t care, if someone wants to make a few parts â€" that’s OK be me â€"

> have at it. I will do my part for free. My intent is to build some FE models

> â€" first of the ribs, and them of the overall wing.
>
> For whatever
> reason, I’ve always be able to tell the things that I will enjoy even before

> I do them. I am absolutely fascinated with soaring and have no doubt that I

> will enjoy doing it. I’ve told myself for a while now that I’m going to be

> knocking off of the 60 hours/week crap and starting to do more of the things

> I enjoy. I’m planning on living to be a hundred, and at 53 I realize I’m a
> little more than ½ done and need to pick up the pace on the hobby front. I

> plan on doing some hang gliding in preparation for flying the CDII and there

> is a lot of soaring up in the Pacific North West where I’m looking to

> retire. Having read where the average age of a sailplane pilot is

> 60-something, I can see why â€" only the old farts have enough time to do it!
> But, I’m cheap and I like building things. So, the two planes I’ve looked at

> that appear to be promising is the CD, and the other is the HP-24. Two
> different birds, but both interesting
> in their own way. I could see

> building both of them once I retire, but I think I’ll start with the

> CDII.
>
> With regard to your question about the pilot location, I think
> there was positive response to putting him below the wing like the Arc. This
> gives a lot of flexibility for locating the pilot after the fact. In fact,
> this would allow maximum flexibility for pilot weight (easy to shift the

> pilot CG) and even the addition of an engine. I can’t remember now, but

> someone was going to look into the clear Mylar for covering the
> center-section like the Arc to improve upward visibility. You do make a good
> point about the fuselage helping with stall recovery, but is that going to

> be a problem? Were other CDs having difficulty with stall recovery? I don’t

> remember reading anything about that. Also, if the pilot goes below the

> wing, then there isn’t much reason to sweep the wing, is there? IF we stick

> with the same wing as the CDI then any current tooling would work.
>
>

> Right now, I’m trying to layout a center box that the wings and tail
> can connect to.
>
> --- On Sun, 3/18/12, russell wilson <ruzty27@...>
> wrote:
>
> From: russell wilson <ruzty27@...>

> Subject: Re:
> [Carbondragonbuildersandpilots] Re: CDII -fuselage
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Date:
> Sunday, March 18, 2012, 11:36 PM
>

> Â
>
> hi..kenny you started
> out asking about pilot position.....what have you decided? kenny your

> not a pilot of any aircraft...you have said you are not going to build any
> thing...

>  what are you doing?what is your goal? id like to
> add....a truss tryangular boom ( pointing down) is good as it
> resitsts spin. and for glide path controll a droge shute is your

> lightest option.aft tail mounted for stability and its wake does not afect
> any surface....retractable would be good.

> Â russ.