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-   -   1/2A Mini-mag? (https://www.rcuniverse.com/forum/1-2-1-8-airplanes-70/9910572-1-2a-mini-mag.html)

ProBroJoe 08-04-2010 12:03 PM

1/2A Mini-mag?
 
1 Attachment(s)
Well, lookie what I have here... anybody up to the task of building a Mini-mag SWR ?;)

These outlines were sketched from an overhead shot of the ARF contents. I scaled the PDF for a 24" wing (which comes out to be about 140 sq in.) and I've put the CG marks at 25% of MAC.

So, ummmm, who's gonna be the first?


R/C Phile 08-04-2010 12:15 PM

RE: 1/2A Mini-mag?
 
Would you happen to have a view the wing profile or it the NACA number for it?

It would seem like a pretty straightforward design to do..

jeffie8696 08-04-2010 01:22 PM

RE: 1/2A Mini-mag?
 
Cant wait to see one.

combatpigg 08-04-2010 03:27 PM

RE: 1/2A Mini-mag?
 
Nice job Joe. I didn't realize how compact the design is, all I've ever seen before [of the Magnum] were photos at various angles.
Never a direct overhead view till now.
I think you nailed the size just right.
Any self respecting 1/2Aer who has a pair, [a pair of hot 1/2A engines, 1 for a spare] should be onboard with this one.

ProBroJoe 08-04-2010 07:31 PM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
She sure does have some nice lines, doesn't she? [8D]

I gotta see how my first SWR turns out before I attempt this one... I think one of the SWR experts should show us how it's done.... I may even look the other way if it becomes a mid-wing to make hand-launching easier!

RCF... a true Sheet Wing Racer (SWR) simply has a 1/4" thick balsa sheet wing that's been shaped somewhat to resemble an airfoil - see my recent QB-150 build for some pics of what I'm talking about. Or, do a search here and it should turn up a bunch of hits of other member's projects.

Here's an updated .PDF with the ailerons sketched in...

combatpigg 08-04-2010 07:37 PM

RE: 1/2A Mini-mag?
 
The NACA # of my 150 MPH .061 powered SWR is 0000.....[8D]

jeffie8696 08-04-2010 07:50 PM

RE: 1/2A Mini-mag?
 
Hey Joe Isnt that a Hawker Hunter?

ProBroJoe 08-04-2010 08:19 PM

RE: 1/2A Mini-mag?
 


ORIGINAL: jeffie8696

Hey Joe Isnt that a Hawker Hunter?

Heck if I know.... you're talkin' to the guy that's not into full scale airplanes, remember? :D


ProBroJoe 08-04-2010 08:33 PM

RE: 1/2A Mini-mag?
 
double post - deleted

jeffie8696 08-04-2010 09:30 PM

RE: 1/2A Mini-mag?
 
And if you thought it was a warbird you would shun it completely http://www.rcuniverse.com/forum/js/f...ey/msn/lol.gif

combatpigg 08-07-2010 08:48 PM

RE: 1/2A Mini-mag?
 
Solid wood would be simpler for the wing than a bunch of bits and pieces, but I'm tempted to try something different.

ProBroJoe 08-08-2010 08:38 PM

RE: 1/2A Mini-mag?
 
Is that a hint as to what you're up to? :) I suppose with a pieced together wing, you'd have the option of customizing the density distribution to put the good wood where needed.


MJD 08-08-2010 09:54 PM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
Here are top views of the 139 sq in and 100 sq in versions I drew some time ago. I didn't like the small tip chord on the direct scale down version of the wing and tweaked the top profile a bit. Project #73.

combatpigg 08-09-2010 02:37 PM

RE: 1/2A Mini-mag?
 
Yes, it doesn't hurt the styling to make the tip chords more useful. This plane could never be made as light as a bare bones delta. You would need to have a militant attitude about how much material you allow to come onboard to make this plane really successful in a small size.
This wing isn't much different than the one on the BatOuttaHell, but there is more bulk in this layout than the flying wing's.
This is the kind of a design contest that would interest me the most. To see how many different "takes" on a simple drawing there could be towards 3 goals...

1. Beauty and faithful execution to the drawing
2. All out speed or some other measure of the model's performance
3. Lightest weight, least amount of parts, simplest construction

There wouldn't need to be any judging or voting, just designers working towards these goals with a way to display their work at a future date. The end result would be rewarding enough and might inspire some to actually build a model airplane!

We had projects similar to this in High School architecture and shop classes.
This would be a fun project for a model plane club that is into modeling planes.

MJD 08-09-2010 04:40 PM

RE: 1/2A Mini-mag?
 
Yup, deltas and flying wings are a minimalist exercise for sure. Most of them.


combatpigg 08-09-2010 05:05 PM

RE: 1/2A Mini-mag?
 
My first impression so far after scaling up the 8x11 print out is the fuselage is just about right for a Cyclon and the wing seems ridiculously small.

Typical Magnum?

The question about the Magnum is this....what is it supposed to excel at? Looks or Speed?

As a .40 sized model it does a pretty good job of both. A guy at the speed forum clocked 195 mph with one....with a Nelson pylon engine capable of a little over 200 mph on the perfect airframe. I doubt if a guy with just a few runs on his Magnum can be compared to the average pylon racer with 100s of flights on his combo, a combo that that has 1000s of flights logged by an entire racing community.
So, here we have a great opportunity to see if you can scale down a pretty optimal model design to 1/2A size and see how it measures up to where the bar has been set for 1/2A performance.

craigdyer 08-10-2010 03:11 AM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
Hi All,

I'm in the process of building a MM....not sure of the best way to do the turtle deck, any suggestions?

I plan on sticking a Norvel revlite .074 in it.

Kind Regards, Craig.

craigdyer 08-10-2010 03:15 AM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
more pics

ProBroJoe 08-10-2010 06:47 AM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
Oh no! What have I started? :)

Lookin' killer Craig! If I were to tackle the project, I think I'd do the canopy/turtle deck carved from a hunk of foam like CP did on his Outlaw Mustang (You can find it by doing a search on "COMBATPIGG'S CONTEST ENTRY".) Everything below that straight line from firewall to the tail would be traditional slab-sided construction with tri-stock in the corners. Alternatively you could do a plastic or painted foam canopy and a built-up turtledeck using formers.

CP, MJD's top sketch pretty much jives with my full size layout of a 24" span and ~140 squares.... here's the shot it was sketched from and a few others taken from the web. Maybe these will help?

I think for this exercise, looks should be paramount - there's just something about the lines of a Magnum....



ProBroJoe 08-10-2010 06:49 AM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
Oh, I adjusted the elevators to be true to form in this .PDF


combatpigg 08-10-2010 10:51 AM

RE: 1/2A Mini-mag?
 
1 Attachment(s)
The top is done with blue foam. I tape off the wood box so contact cement doesn't get on the wood, then glue the block of foam on top. The block has already been bandsawed to a pretty close fit to the top of the box. After doing the shaping with a 40, then 100 grit paper, it's time to tape off the whole works with clear packing tape. I do this to provide a barrier if using CA glue to harden the fiberglass, or to keep epoxy resin from seeping into the foam and not saturating the glass cloth.
I cut out a single piece of 2 oz cloth, lightly sprayed it with 3M77 and pulled it over the foam block. It took very little laminating resin [you could even use polyester] to do the trick.
This morning I trimmed off the excess cloth at the spot where the foam attaches to the box and it's basically done. Later, I'll pop off the foam block to scoop it out a little bit, but will leave some foam there for strength. I'll also do away with some of the balsa sheeting that the foam is attached to, then glue the foam to the wood permanently.

highfly3D 08-10-2010 11:53 AM

RE: 1/2A Mini-mag?
 
are the wings absolute flat..balsa

combatpigg 08-10-2010 01:45 PM

RE: 1/2A Mini-mag?
 
Since the wing has 10 inches of chord at the root, I'm making my wing 1/2" thick [5%].

I'm also going to kick in some dihedral to center the thrust and mass of the plane better on the wing.
Low wingers just look kind of silly without a little dihedral, like a plane flying upside down most of the time.

1/2" solid sheet might not be too practical, so the wing will need to be built up wood frame, or composite.

ProBroJoe 08-10-2010 04:13 PM

RE: 1/2A Mini-mag?
 
...and don't forget the anhedral on the tail! [8D]

Oh boy, oh boy, oh boy.... CP's at it again - I can't wait!!!! :)

(How's that fer setting the bar?)

hllywdb 08-10-2010 06:54 PM

RE: 1/2A Mini-mag?
 
With enough anhedral on the tail and just a smidge of duct work and leading edge tweeking, this could make a realy cool 1/2a stand-off scale F4 Phantom! Or am I looking at this wrong.


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