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Author Topic: P30 wing with MID105  (Read 2285 times)
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tctele
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« on: August 08, 2010, 03:30:09 PM »

Hi, Anyone used any of the MID (102,103,105) on a wing yet? I've just drawn one up in compufoil with a 2.5mm carbon TE and boy is the latter part of the airfoil thin, maybe less than 1mm. Just thought maybe someone had had a go and how where the results? I think I'll have to cut the top latter part over thick and then sand to the final profile. No doubt about it having carbon caps. My original thought was 1/32 balsa but I think this will be to flimsy near the TE, maybe 1/20th. I'll use a 5.1mm carbon F1B stab tube as a spar. Any suggestions how to join the tube securely at the dihedral break? This will be a five panel affair similar to Andrew's 'Piffle' P30.
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Tmat
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« Reply #1 on: August 08, 2010, 09:55:51 PM »

Sounds like a plan. The thickness near the back is in-line with current F1B and Coupe airfoils, so I see no problems if you use carbon caps. 1/32" would work for ribs. 1 mm would be fine too. I've joined the carbon tubes at the D-break on my latest P-30 using a thin glass fiber dihedral brace (1/32" thick) that fits inside the carbon tubes. I add some 1/16" balsa to either side to increase the gluing area. 1/32" plywood would be a good substitute.

Tony
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tctele
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« Reply #2 on: August 09, 2010, 05:22:09 AM »

Thanks Tony, I was funnily enough thinking on the same lines re the dihedral brace, ply and balsa. I'll cut some 1mm ribs at the weekend and do a test piece.

Tony
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Tmat
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« Reply #3 on: September 27, 2010, 01:41:09 PM »

Tony,
Any progress on the new P-30 wing? Any photos? Planform?

Tony
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tctele
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« Reply #4 on: October 04, 2010, 03:04:20 PM »

Hi Tony, it's now turned into coupe wing, 1180cm, 120mm chord, balsa built up LE, 4mm carbon spar, .5mm TE, 1mm ribs and 1mm caps, 2mm of 'left' skewed in at the dihedral breaks, no washout but intend to use a gurney TE where needed. Will be covered in mylar lower surface and possibly tissue over mylar on the upper surface. Give me a week. Tony
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Tmat
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« Reply #5 on: October 04, 2010, 04:48:01 PM »

So what happened to the P-30 wing idea?
Incidentally, I would have thought that the Mid102 or Mid103 was a better choice for P-30.

I have to do some simulations using this type of airfoil compared with a very thin foil of similar camber to see if it makes sense for P-30. I really like the simplicity of Phil Ball's solution to use a very small carbon d-box from Szabo (Hungary) and no additional spar (D-box contains an integral carbon web) and ribs with carbon caps and a small carbon trailing edge (1.5 mm wide max). His wing weighed 12 grams IIRC with Mylar covering. I can see such a wing with constant chord being very quick to build (an evening not including covering) but would be very stiff and totally weather proof. But the tiny D-boxes force you to use a thin airfoil. Hence my pondering of what sort of profile would work best for P-30. I'm also convinced that a higher aspect ratio wing (100 mm chord max) has some merit for reduced climb drag if the overall weight can be kept at or under 40 grams.

Tony
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« Reply #6 on: November 12, 2010, 03:30:59 PM »

I was just looking at these sections this morning in the P30 book. MID 102 looks promising for a 50g open rubber model. As you guys have been saying, it is a bit thin near the trailing edge. I wonder what the potential aerodynamic result would be of either thickening the section towards the trailing edge or cutting the last 10% off the section? I was thinking of about a 5 to 5 1/4" chord with a TE of about 1/2" by 3/32" deep. I'm not sure about going all carbon on it as I'd like to build it on a flat board. Any thoughts?

Adam
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Tmat
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« Reply #7 on: November 12, 2010, 03:41:40 PM »

Thickening the trailing edge will add a little bit of drag, but the effect at our Reynold's numbers is minimal.

I like the carbon trailing edge as it's so simple to produce (just take a piece of stock rectangular carbon and glue it on!). But you do need carbon caps to tie the carbon trailing edge to the ribs. For a conventional balsa construction a thicker trailing edge makes sense.

Incidentally, the trailing edge area of the Mid 102 is thicker than what most people are currently using for F1B and F1G models. However, as you know they are all produced with carbon caps...

Tony
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Allardvanw
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« Reply #8 on: March 01, 2011, 04:38:51 PM »

Dear all,

Does anyone have the coordinates of the MID series airfoils? They look very interesting for F1A.

Thanks,
Allard
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Tmat
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« Reply #9 on: March 01, 2011, 05:58:27 PM »

Allard,
They are available on the Yahoo X-foil group under files:
http://groups.yahoo.com/group/xfoil/files/Free%20flite%20airfoils/

You need to join, but then you get access to the files.

I can also send you the co-ordinates if you want.

Tony
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Re: P30 wing with MID105
« Last Edit: March 01, 2011, 06:40:31 PM by Tmat » Logged

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Pete R
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« Reply #10 on: August 16, 2011, 12:01:03 AM »

Tony,
Do you have a source for the Szabo  P-30 D boxes?
I woulod very much like to aquire a couple.
Cheers!, Pete R (Texas)
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Tmat
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« Reply #11 on: August 16, 2011, 05:51:21 PM »

See here:

http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=5069.30

Tony
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« Reply #12 on: August 17, 2011, 02:16:39 AM »

Got it!
Thanks!!!
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tctele
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« Reply #13 on: August 17, 2011, 03:42:59 PM »

If you pm me I've this years catalogue. Tony
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