Quantcast

Downscale Quinstar!

The Rocketry Forum

Help Support The Rocketry Forum:

ActingLikeAKid

Well-Known Member
Joined
Nov 17, 2015
Messages
1,133
Reaction score
13
I have a (stock) Estes Quinstar that I love flying - it's low and slow, but it's a cool spinning flight. So it's great for small fields and such.

It occurred to me: I know people are out there 3d-printing and laser-wood-cutting upscale Quinstars. Which is really cool. But I don't have a 3d printer or a CNC cutter.... so I had a wacky idea: Why not downscale the Quinstar? As it is, it's 5 sheets of laser-cut balsa. What if I scan it, downscale to fit a 13mm motor, reprint it on paper, then cut it out of cardstock? It would be fiddly, I think, but it would be neat....
 

neil_w

Marginally Stable
TRF Supporter
Joined
Jul 14, 2015
Messages
11,023
Reaction score
3,872
Location
Northern NJ
I might still be inclined to use 1/16" balsa rather than cardstock. I think it's easier to cut and work with in general, and weight shouldn't be an issue.

And it can be hand cut. Doing a hand cut downscale sounds like a breeze compared to my upscale.

I say go for it!
 

rharshberger

Well-Known Member
Joined
Oct 13, 2014
Messages
9,784
Reaction score
1,756
Location
Pasco, WA
I have a (stock) Estes Quinstar that I love flying - it's low and slow, but it's a cool spinning flight. So it's great for small fields and such.

It occurred to me: I know people are out there 3d-printing and laser-wood-cutting upscale Quinstars. Which is really cool. But I don't have a 3d printer or a CNC cutter.... so I had a wacky idea: Why not downscale the Quinstar? As it is, it's 5 sheets of laser-cut balsa. What if I scan it, downscale to fit a 13mm motor, reprint it on paper, then cut it out of cardstock? It would be fiddly, I think, but it would be neat....
Print the patterns on self adhesive label paper and half your papering is done.
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
sounds like a good idea. It might be strong enough to do a fold-over construction, where you laminate a cardstock sandwich folded over a thin cereal-box type cardboard sheet in the middle.

you could also try some of the free 13mm cardstock templates from Art Applewhite:
http://www.artapplewhite.com/free.html
 

JumpJet

Well-Known Member
Joined
May 19, 2011
Messages
747
Reaction score
44
Card stock is very heavy compared to balsa. I would use some firm 1/32" balsa.


John Boren
 

rstaff3

Oddroc-eteer
Joined
Jan 18, 2009
Messages
11,759
Reaction score
14
I cannot believe that cardstock wouldn't work just fine. I have lots of cardstock saucers and saucer-lile objects. That being said and IMO, balsa could actually be easier.
 

PhlAsh

Well-Known Member
Joined
May 9, 2011
Messages
969
Reaction score
55
Go to your local Michael's (or othersuch framing store) and ask what they have for matte remnants. I bought a decent sized sheet of 0.07" matte board for my (1:1) UFO Invader clone
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
IMG_0517.jpg

See if these PDF files help you out any.
Many thanks! I printed these up at 72%, about 13/18 ratio, on regular printer/copier paper, then glue sticked that to 110 card stock, then glue sticked another layer of printer paper on the other side. Still a little flimsy, but very light, about 0.4 oz so far. I opted not to cut out the lightening holes, which does not look quite as cool, but I was worried about strength of the 3 ply paper/cardstock sandwich. The main inner star would probably be plenty strong enough, now that it is glued up and dried. The outer K triangle points have a little flex in them, so I am thinking about adding some bracing to the inside underneath part near the neck of that joint. Possibly just a short length of launch lug hidden in there would help to strengthen the joint. Should be fine for 13mm motors, I will weigh it after I add the 13mm motor mount tube and 13/18 centering rings.
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
I am going to build another one with my laminate layers reversed, instead of a cardstock sheet sandwiched between two sheets of copier paper, I am going to use two sheets of cardstock to sandwich a single sheet of copier paper. The two cardstock sheets will be rotated 90-deg. Hopefully this will be strong enough after punching out the holes, we'll see. When you print these 5 sheets up at 72% scale you can fit all of them on one 8.5"x11" page. My initial prototype seems plenty strong enough after letting the glue with generous fillets thoroughly dry overnight. Not sure if I would try launching this downscale on an 18mm engine...probably strong enough, but an 18mm engine sticks out the aft end quite a bit, c.g. may be too far aft, just looks questionable. But these spinning saucer rockets are not really within the range of my mind sim.
 

ActingLikeAKid

Well-Known Member
Joined
Nov 17, 2015
Messages
1,133
Reaction score
13
I actually bought a second Quinstar kit with plans to scan (and then, y'know, that need was avoided!) but I think I'm going to paper this one, at least partially. It's a gorgeous kit and a fun flyer, but it's at least 30% CA by now.
 

ActingLikeAKid

Well-Known Member
Joined
Nov 17, 2015
Messages
1,133
Reaction score
13
paperquin.jpg
Something like this (quick and dirty, MS Paint) -- just papering (in red) the bits that would be "outboard" of the star, and a little bit beyond the joint so the joints don't snap. And even if I lose 30% of the altitude, still a fun flyer. And I can always eschew the motor mount and stuff a D in there.
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
ActingLikeAKid is ThinkingLikeAnEngineer. :) For the 13mm 72% mini-downscale, I was thinking along those same lines, that you could also paper the paper in regions where you need to add strength, rather than making the entire sheet multi-ply constant thickness. Just use paper doublers in the region of the wider slots might be all you need. The original balsa sheet is 1/16", right? so if you scale the thickness by 72% that is roughly 0.0625*0.72 = 0.045 or 1.143 mm, about 4 ply of 110 cardstock. If you use thicker than downscale sheets, then you may have to adjust how wide you cut the slots from the scaled pattern. I don't think you need 4 ply cardstock for the entire sheet, but maybe some doubler or tripler cardstock to beef up the outboard joint area shown here:

Screen Shot 2017-06-01 at 7.55.09 PM.png


Here is the three ply, cardstock over copier paper, dry fit of the star cage. Strong enough to cut the holes, and looks really cute next to a 13 mm engine casing.
IMG_0518.jpg
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
IMG_0519.jpg
These are the two variations on the paper sandwich theme. I have one more idea to try with a single cardstock ply and local doublers where needed, we'll see how that turns out. I should have white out the letters on the print out before photocopying them to the cardstock, but they kind of look cool.

Anyone want to take the challenge of downscaling this further, to MICRO? 6mm MMX motors?
6/18 scale is 0.333.
 

GlenP

Well-Known Member
Joined
Oct 4, 2014
Messages
2,194
Reaction score
484
I thought I would try one more 13/18 downscale of the 13/18 downscale. (Very similar to a 13/24 ratio of the original) The main body tube is now 13mm rather than 18mm. This one is a single layer of 110# cardstock. I might have to add some reinforcement to the neck joint at the K triangles, white glue is still wet, it might dry hard enough. If it still feels flimsy, I might add a thin doubler cardstock strip to each side of the neck joint. This is what the 72% and the 72%-squared downscales look like with 18mm and 13 mm motors. I don't think I would try to fly with an 18mm, might be okay for an A or B, but a C might rip it apart, and it just looks too bottom heavy.

IMG_0520.jpg

Really cool interlocking design with just 5 sheets, very clever kit and fun to build and fly.
 
Top