Russ,

A drogue isn't designed to slow your airspeed - it's designed to increase your sink rate. Even with a drogue deployed, you still have full control over your speed envelope. A 'drogue 'chute' that's big enough to slow your airspeed uncontrollably is called a parachute.

You'll forgive me for mentioning it, but you seem obsessed that no one build a CD out of anything other than 1/32" ply and that no other material could possibly replace it! Read back over my early posts - I'm not fixated on reducing weight - that's never been my primary goal. I want to build an all-composite CD because in my climate plywood will deform very rapidly even when it is sealed (and made heavier, BTW) with epoxy, varnish or paint. My secondary goal is to make my CD stronger than the original wooden one. I think my test pieces so far have conclusively proved that it will indeed be a lot stronger. As I mentioned earlier, Rick has offered to weigh a few spruce ribs for comparison - just be patient and the results will be published here.

Finally, why in God's name would you want to fly a micro-lift glider like the CD so fast as to induce wing flutter - it's designed to be flown at practically walking pace!

Phil.

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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 23:22
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Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage




hi phil
how about cutting a small section of your test rib and making a small section of standard rib from the same section......a pencil on the bench and a 600mm steel ruler balance beam might indicate what is lighter.
with the scary moments like you point out.....every time you have to fly through a flyte perameter..you are,i am,any one that modifies there aircraft is a test pilot....we will not know what our volocity to never exeed is untill we find it...thin carbon scined d tube has a diferent spring like property..i wonder if a droge would slow you enough to get out of a flutter situation in time?

russ

hi kenny
how much needs to be cut of the wing tips to carry a 90kg pilot?just for someone that wants to get into a standard dragon,but they are too heavy.wings only for now.

for simiplified controlls look at an aust made aultralight..jabaroo...he uses push pull cables same as jetski steering cables.
russ.


On Tue, Mar 20, 2012 at 2:16 AM, Kenny Andersen <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


@ russ
I was thinking that most spins were initiated by a stall, but I'm sure there are other ways of getting from here to there. 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.


@Phil
Are 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 <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: Monday, March 19, 2012, 6:39 AM





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

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!

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!

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
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Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage




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



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?!

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!

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.) 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.

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.

Phil.

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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
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Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage





tryangular tail boom resists spin(when it points down) ,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.

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.


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.

russ.




On Mon, Mar 19, 2012 at 5:38 PM, Kenny Andersen <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


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 – I’d wanted one for 30 years, and I finally got it – 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 – 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 – 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 – that’s OK be me – have at it. I will do my part for free. My intent is to build some FE models – 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 – 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 <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:

From: russell wilson <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: Sunday, March 18, 2012, 11:36 PM



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.
russ.