Duece elliptical fin pattern?

[pdooley]

I recently purchased a Fliskits Dueces Wild, and would like to build it with elliptical fins.
Imagine the Astron Sprint style fin, scaled to the Duece kit.
However, unlike the Sprint, I want my Duece fins symmetrical.

I seem to remember seeing a photo of Duece with fins like this, but can't remember where

Does anybody have a scaled fin pattern handy? I can't figure out how make a perfect ellipse, short of using a function. Is there a computer program out there that can trace an ellispe inside the standard boxy Duece fin?
That would be cool because I could use the original Fliskits fins.
I don't think removing that little area from the fins would make the rocket unstable.

Any ideas??

 

[jflis]

Interesting idea.

I've attached a pdf file with an elliptical fin pattern with the same cord and length as the Deuce trapizoid fin. There *is* some loss of fin area with the ellipse, but this shouldn't be an issue with regard to stability on this model.

Note, in the pdf I also included a rough sketch of the *original* Deuce fin pattern from my first one back in the 70's. This is probably where you got the idea of the elliptical fin.

Here is a pic of the Deuce flying with this original fin pattern:
https://jflis.com/hobbies/rocketry/photos/13-mar-01/duce02.jpg

Here's a better pix of that version of the Deuce:
https://jflis.com/hobbies/rocketry/photos/duce01.jpg

Good luck and be sure to post pix!!!

jim

 

[pdooley]

How's that for product support?
That's exactly what I was looking for.
Thanks Jim!

BTW, that PDF has already been downloaded 20 times, maybe some other TRF members will build one too.

I will post some pics of mine(whenever I get time to build it

 

[jflis]

well, i figured *someone* was going to do it, it may as well be me

 

[pdooley]

OK Jim, you asked for it

I finally got a chance to print the elliptical fin pattern.
Here's a pic of pattern on stock fin material:

 

[pdooley]

and the double trace:

 

[pdooley]

the cut fin stock:

 

[pdooley]

and the finished product:

 

[pdooley]

close-up of fins:

 

[jetra2]

SWEEEET!

Great job Pat! Nice job going back to the roots of what I feel can now be called a classic kit! I wanna see it at HERC next month!



Jason

 

[pdooley]

thanks Jase!

There may be a Duece drag race at the next meet....you up for it??

 

[jetra2]

LOL!

Ok! You got yourself a competitor!

Next, after that, we could do a real cool drag race. My Super Big Bertha on an E18-7W reload vs. yours on a E9-6! I'll even give you a head start and use the supplied Crapperhead! (the one with the most pyrogen, of course! ) Do you accept my challenge?

Jason

 

[pdooley]

Yer on, I have the ut-most confidence in my E9/SBB setup

You gotta show me how those reloads work, I have never seen one up close.

If my SBB fails, I will load up the JetraHPR downscale project with 4 D12's
:kill:

 

[jflis]

now, *that* looks very cool! I love it. Can't wait to see it fly. It will be interesting as the CP will move forward slightly (not enough to matter for stability, but none the less) due to the smaller fin area, but the lower drag of these fins (even if left flat edged) will make for an interesting balance...

Let's see her painted now
jim

 

[Fore Check]

*heh heh heh heh heh*

You said "crapperhead."

 

[eugenefl]

Originally posted by pdooley
thanks Jase!

There may be a Duece drag race at the next meet....you up for it??

Uh, we could go 3-way on this race. I've got one too! So does Russell and ChrisVG. Very cool. Way to pay homage to the real "classic" Deuce.

 

[pdooley]

you got it Eugene, just don't jinx us, I have visions of all 3 Dueces going in the pond!!

BTW, I got 30ft of speaker wire from HomeDep, so I won't be cringing huddled over my launch pad

 

[lalligood]

Seeing the Deuce with elliptical fins gives it, dare I say, a bug-like appearance along the lines of the Binder Design Dragonfly. Modify the Deuce fin pattern to resemble butterfly wings & it would kinda look like one with a very long abdomen...just hold it backwards like the BD Dragonfly.

And while I'm sure some people will jump to a "what's he been smokin'?" conclusion, think of all the different Deuce modifications that people have already built... Doesn't sound so strange, not does it?!

 

[Wingarcher]

If you want to make an ellipse....

Create two spaced fixed points in the middle of the area you wish to ellipse. Make a loop of string big enough to go around both points and still leave room for a pencil. Pull the string loop tight against the two points with a pencil or some other implement inside the loop. Drag the pencil around inside the taut loop (like making a circle with a string and a nail). You'll get an ellipse. Of course, you can control what it looks like by varying the distance between the foci (the fixed points) and the length of your loop of string. Calculus would give you the details if you want them!


N

 

[TheRadiator]

Wow, that just gave me an excuse to buy another Deuce! Too bad I just put a FlisKits order in!

 

[SwingWing]

Wow, looks nice. It might look good with a more rounded off nosecone.

 

[jetra2]

Yeah, a Big Bertha NC would look nice, as well as the Rhino's NC.

Jason

 

[jflis]

Originally posted by TheRadiator
Wow, that just gave me an excuse to buy another Deuce! Too bad I just put a FlisKits order in!

Nick,

If'n you want to add a deuce to that order, just drop me an email and we'll get you all set up