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New world FAI hlg record! (Read 14935 times)
tonymat
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Re: New world FAI hlg record!
Reply #20 - Oct 1st, 2008 at 3:38pm
 
Here is some more information regarding the airfoil used by Ishii Mitsura.
I've attached a screen capture of the results from X-foil performed by Brian Eggleston. Aki and Ishii kindly gave their permission to share these results with our glider "friends"!

You can see the characteristic shape of the airfoil and ponder how you'd make it!

Tmat
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« Last Edit: May 18th, 2009 at 3:08pm by tonymat »  
 
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Re: New world FAI hlg record!
Reply #21 - Oct 1st, 2008 at 3:42pm
 
The above diagram showed Ishii's profile at a Reynold's number of 200,000 which corresponds to a launch velocity of about 100 ft/sec. Note Brian used a c/l of zero.
The diagram below shows the same section at a Reynold's number of 24,000 suggested by Ishii to correspond to the gliding Re.

Tmat

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« Last Edit: May 18th, 2009 at 3:08pm by tonymat »  
 
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Re: New world FAI hlg record!
Reply #22 - Oct 1st, 2008 at 3:46pm
 
Finally, you will find below the co-ordinates of Ishii's profile, as smoothed by Brian (X-foil requires much more data than is usually provided by the typical co-ordinate methods).

Ishi_sm70pts
    1.000000    0.008180
    0.984639    0.009948
    0.953341    0.013542
    0.921128    0.017221
    0.888960    0.020809
    0.856846    0.024215
    0.824761    0.027365
    0.792673    0.030213
    0.760545    0.032751
    0.728363    0.035021
    0.696134    0.037056
    0.663859    0.038897
    0.631541    0.040581
    0.599192    0.042147
    0.566801    0.043630
    0.534401    0.045092
    0.502036    0.046487
    0.469663    0.047785
    0.437327    0.048972
    0.405027    0.049987
    0.372753    0.050793
    0.340511    0.051349
    0.308298    0.051611
    0.276121    0.051543
    0.243984    0.051099
    0.211885    0.050241
    0.179893    0.048925
    0.148149    0.046974
    0.116750    0.044115
    0.086267    0.040040
    0.057526    0.033579
    0.031101    0.024046
    0.012180    0.013641
    0.003989    0.006826
    0.000560    0.002608
    0.000336   -0.000936
    0.003754   -0.004321
    0.011570   -0.008556
    0.029782   -0.013943
    0.059110   -0.019442
    0.090018   -0.024120
    0.120774   -0.027108
    0.151830   -0.028380
    0.183165   -0.028212
    0.214718   -0.026871
    0.246415   -0.024604
    0.278222   -0.021613
    0.310143   -0.018084
    0.342192   -0.014213
    0.374352   -0.010201
    0.406433   -0.006277
    0.438390   -0.002650
    0.470295    0.000523
    0.502236    0.003194
    0.534252    0.005391
    0.566316    0.007152
    0.598410    0.008491
    0.630537    0.009421
    0.662694    0.009968
    0.694874    0.010154
    0.727089    0.010010
    0.759330    0.009573
    0.791591    0.008874
    0.823871    0.007942
    0.856172    0.006807
    0.888496    0.005506
    0.920812    0.004056
    0.953142    0.002466
    0.984568    0.000831
    1.000000    0.000000

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« Last Edit: May 18th, 2009 at 3:13pm by tonymat »  

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Ishi_70pts.jpg
 
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Re: New world FAI hlg record!
Reply #23 - Oct 1st, 2008 at 3:48pm
 
Does anyone have the capability to convert a .pdf file to a .jpg or bitmap? If so, let me know and I'll send you a copy of the drawing so that you can convert it to a picture file. Then it can be posted here.

My E-mail is: tmathews1@sympatico.ca

Tmat
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Re: New world FAI hlg record!
Reply #24 - Oct 1st, 2008 at 5:29pm
 
hi,
You can do it with acrobat 8 by using the selection tool from the tool drop down menu or the snapshot tool. once you have the area you want on the clipboard you can paste it into a blank image file in any art program etc, then save as a jpeg.
greg
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Re: New world FAI hlg record!
Reply #25 - Oct 1st, 2008 at 6:09pm
 
Thanks Greg!
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Re: New world FAI hlg record!
Reply #26 - Oct 1st, 2008 at 9:15pm
 
Thanks to Joe Mekina, I have a better quality .jpeg to share!
Thanks Joe!

Tmat
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« Last Edit: May 18th, 2009 at 2:47pm by tonymat »  
 
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Re: New world FAI hlg record!
Reply #27 - Oct 2nd, 2008 at 10:08am
 
For me Mitsasura's airfoil would be quite the challenge to carve/sand. How about building a wing jig for the bottom camber.  Take the first third (or whatever you think would work) of the airfoil and draw a horizontal line through it at mid height. Cut  patterns on that line so that you have the top and bottom. Carve/sand the top and bottom on separate sheets of balsa. Glue the flat sides together and you have the front part of the airfoil. Build a tough carbon balsa sandwich spar and glue it to the back of the carved airfoil. Make ribs for the rest of the airfoil and use a carbon trailing edge. Carbon cap the ribs over the spar onto the balsa front,locking it all together on the jig as you would for hi-tech wing construction. Cover with whatever you think is appropriate. I bet somebody is all ready doing something like the above. Personally I like it because I am one of the few in this hobby that does not enjoy sanding/carving! Yep, I'm a heretic.

Now I do not know if it would be stiff or light enough. Any thoughts?

I plan on trying something like this but my plans for building and actually building do not have a very high degree of correlation right now  Cry

The Eggleston/Allnut airfoils in Free Flight Quarterly and the NFFS Symposium had me thinking along these lines. According to Sergio Montes there will be a new airfoil in the January FFQ that might have application for TLG's. But alas, it is in all in my head. A beautiful vaporplane Smiley

I wonder what would happen with these airfoils if our TLG's weren't  limited to 36" span?

Congratulations to Ishi Mitsasura on the record and a very cool plane!

Tony, thanks for posting the airfoil and plane details.

Derek
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« Last Edit: Oct 2nd, 2008 at 10:16am by DerekMc »  
 
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Re: New world FAI hlg record!
Reply #28 - Oct 2nd, 2008 at 3:57pm
 
Derek,
I agree, such a wing section is not easy to carve! Your description of a possible construction method is what I was trying to describe earlier. But you did a much better job of explaining it! I've included a sketch of the proposed method below.

There are several methods that could work.
1) carve it from solid balsa in the traditional manner (razor plane and sanding tools). pros - allows for curved planform, cons - time consuming and dificult to duplicate with accuracy
2) carve from solid balsa with metal templates and sanding tools - pros - increased accuracy and repeatability, easier to produce, cons - only suitable for straight LE, requires accurate templates
3) Balsa d-box and carbon reinforced rear structure. pros - allows for curved planform, accurate and repeatable, cons - requires undersurface jig and templates for ribs.
4) composite structure, either carbon d-box with ribs, or all foam with glass cloth or kevlar covering, pros - very accurate and repeatable, cons - requires extensive tooling or special equipment

So you have those choices so far as I see it.

The structure you described Derek (like No. 3 above) is very similar to Tetsuo Itoh's "Monster Mk2 - Type B" described in the January 2006 issue of FFQ (Issue No. 18). He uses a balsa d-box with carbon reinforced ribs and trailing edges. And yes it is strong enough for Tlg! You can use much harder balsa for the D-box to add stiffness as well as use light glass cloth over the d-box to add stiffness (at 45 degrees of course). It is also similar to PLoyd's Morris and Discus Dancer outlined here in SFA.

I've been working with Brian and yes, he does indeed have some new airfoils (an extension of his work with F1A Bunt foils) that might be suitable for DLG's. I've also got him working on some new airfoils specifically designed for Tlg's and clg's. But that's another topic and they are not ready for publication yet (I hear another Sympo paper for Brian!).

Certainly if the powers that be hadn't limited the span of hlg's to 1m, there would be more work progressing on alternative structures. It would not be easy to build a 60" glider to a reasonable weight (or find suitable wood!) with a solid balsa structure. Although it certainly has been done. I'm thinking of Phil Ball's models in the U.K. for example, as well as Mark Benn's huge Tlg's.

Fun stuff!

Tmat

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Re: New world FAI hlg record!
Reply #29 - Oct 5th, 2008 at 7:22am
 
First off, Congratulation once again Ishii, very well done!!!!

I used asymmetrical dihedral on a Supersweep back in 1990.  After doing 60 seconds with the model in 1989 I decided I needed more dihedral for a better rollout, and more stab tilt to tighten the turn.  I added a third a third break to the right wing.  This change alone (and a years worth of practice) gave me my first flight of 75 seconds the following year with the same model.  Kids stuff compared to what is going on now.

The cruciform tail can work indoors.  The issue with TLG’s is they need a large amount of vertical area in the tail to stabilize the launch.  Using only a cruciform tail to counteract the yaw induced at launch requires a bunch of area.  This area is acceptable inside, however once you go outdoors that area will weather vane or spin.  That is why the Y tail with a skew became the solution to outdoor designs.  It counteracts the yaw but keeps the vertical area manageable. 

More evidence of this is the large size of Ishii’s rudder in comparison to traditional indoor JLG’s.  I suspect this is also why he has so much dihedral, to prevent spinning in even indoors with such a large rudder.  The excess dihedral brings the center of lateral area towards the front some to reduce the models tendency to spin.

I see a familiar airfoil popping up again.  This airfoil is not new, but had not been used much for glider guys in many years.  I think the Hi Hat from the 1960’s used it, but I would have to dig into the archives to be sure.  It resurfaced in early 2007 on Rob Romash’s Cat II Nifkin.  Stan has been using it on his smaller TLG’s, both indoors and outdoors.  Jim Lewis has been playing with it as well.  Now Ishii has really put the smooth lines of this airfoil on the map!  I am not saying any of the above airfoils are the same, but they are similar.  All are a definite departure from traditional flat bottom, flat back indoor airfoils with a semi-symmetrical front and undercamber rear.

I really wish the AMA rules did not hold us to 100 square inches.  All AMA events will run HLG as AMA, not F1N.  For this reason we will spend our time chasing the AMA record of 90 seconds with a 100 square model.  Once that happens (and it will by 2010 I predict), perhaps we would be better off to align to the F1N rules before Ishii is so far ahead of us we cannot see him!

Well done.  I would LOVE to see a video of the flights if one were ever available.  Exciting times in the arena of Indoor HLG.
~Jim
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Re: New world FAI hlg record!
Reply #30 - Oct 5th, 2008 at 7:56am
 
Hi Jim san,
I am sorry that I did not have a video camera (nor digital camera!). Perhaps no one had a video camera at the record trial, though there were TV crew's 2 (?) TV cameras and some pressmen's cameras there.
Good flying, Aki
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Re: New world FAI hlg record!
Reply #31 - Oct 5th, 2008 at 11:27am
 
I loaded Ishi's co-ordinates into X-Foil and run some comparisons at Re=30,000. I've compared it to a typical freeflight HLG airfoil with flat upper rear surface (Supersweep 22), a Mark Drela AG12 DLG airfoil and the Be6453B which I've had a lot of luck with on my own duration models.

Here are the Graphs:

Cl and Cd
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« Last Edit: Oct 5th, 2008 at 11:28am by JetPlaneFlyer »  

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Re: New world FAI hlg record!
Reply #32 - Oct 5th, 2008 at 11:29am
 
Cl/Cd and Cm
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Re: New world FAI hlg record!
Reply #33 - Oct 5th, 2008 at 11:34am
 
There is not a lot to choose between the 'Ishi' the AG12 and the Be6453B... the 'typical' HLG airfoil does not do well in this simulation.

X-foil does however need to be taken with a pinch of salt at very low Re numbers.
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Re: New world FAI hlg record!
Reply #34 - Oct 5th, 2008 at 11:50am
 
Jetplane flyer. Interesting work. Do you have co-ordinates for the Supersweep airfoil? (Well, I'm sure you do...but can you share them? Grin).
It seems to me that 30,000 Re is a bit high for glide speed. 23,000 to 24,000 is about the range for Ishii's model, and I'd guess that 25,000 would be closer to the outdoor DLG models. Also, to get a real comparison, I think that you need to compare the launch C/d as well. Re of 200,000 is a good place to start. We assumed that the wing would be flying at or near zero lift at the start.

But very good work nonetheless!

Jim, I did see the simularity with Romash's airfoil and with some others as well (even the original Vartanian foil!) to Ishii's foil. He has apparently done some wind tunnel testing to verify this foil btw if anyone is interested.

The new ones are a bit different  though. They use a larger lower surface "chin" that allow for both more thickness (note Ishii's section is 8% thk, and Romash's is 5%) and possibly more camber (for both better glide and structural strength) but still with low C/d for the launch.

But I agree, they all have a "family" resemblance when compared to a standard flat bottomed HLG airfoil.

How did Romash carve his?

Tmat
-no doubt the usual way! Lips Sealed
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Re: New world FAI hlg record!
Reply #35 - Oct 5th, 2008 at 12:06pm
 
here are curves at Re=24,000

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Re: New world FAI hlg record!
Reply #36 - Oct 5th, 2008 at 12:08pm
 
and Cl/Cd and Cm
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Re: New world FAI hlg record!
Reply #37 - Oct 5th, 2008 at 12:11pm
 
And to represent launch Re=100,000 (200,000 looks the same)... the Supersweep and the Ag12 look good at low lift launch condition where there drag is significantly lower than the more cambered airfoils
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Re: New world FAI hlg record!
Reply #38 - Oct 5th, 2008 at 12:14pm
 
And finaly.. the co-ordinates for the Supersweep22:
Upper  X       Upper Y
0.00000      0.00000
0.02140      0.06748
0.09361      0.18130
0.20001      0.29606
0.34922      0.42377
0.56164      0.57678
0.84976      0.75646
1.25669      0.97745
1.78732      1.23012
2.44787      1.50884
3.26832      1.81730
4.18318      2.12486
5.13045      2.41363
6.12972      2.69307
7.19229      2.96740
8.28646      3.22874
9.40094      3.47483
10.53062      3.70482
11.67589      3.91881
12.83567      4.11708
14.00685      4.29989
15.18673      4.46791
16.37551      4.62174
17.57089      4.76166
18.76368      4.88694
19.93786      4.99569
21.08943      5.08895
22.24221      5.17202
23.44559      5.25563
24.45386      5.32626
25.14381      5.34614
25.85176      5.29655
26.84293      5.22705
28.00580      5.14554
29.14288      5.06580
30.30666      4.98430
31.52824      4.89864
32.76903      4.81181
34.00481      4.72523
35.25140      4.63788
36.49618      4.55081
37.73807      4.46381
38.98315      4.37674
40.23344      4.28914
41.48552      4.20156
42.73730      4.11378
43.98979      4.02611
45.24298      3.93825
46.49576      3.85048
47.74895      3.76262
49.00253      3.67486
50.25672      3.58681
51.51110      3.49906
52.76549      3.41101
54.02037      3.32317
55.27526      3.23503
56.53054      3.14710
57.78603      3.05906
59.04182      2.97103
60.29780      2.88300
61.55408      2.79488
62.81067      2.70686
64.06756      2.61865
65.32464      2.53043
66.58223      2.44233
67.83991      2.35412
69.09810      2.26582
70.35648      2.17762
71.61537      2.08943
72.87446      2.00104
74.13404      1.91286
75.39383      1.82438
76.65411      1.73611
77.91490      1.64775
79.17588      1.55938
80.43737      1.47092
81.69916      1.38247
82.96154      1.29402
84.22423      1.20548
85.48751      1.11685
86.75100      1.02832
88.01518      0.93969
89.27967      0.85117
90.54475      0.76246
91.81014      0.67375
93.07603      0.58505
94.34202      0.49635
95.60830      0.40756
96.87289      0.31904
98.12317      0.23134
99.31395      0.14788
100.0000      0.09981
Lower X      Lower Y
0.00000      0.00000
0.00240      -0.04157
0.02480      -0.07959
0.08681      -0.13060
0.18731      -0.19253
0.30402      -0.24815
0.47683      -0.31546
0.69955      -0.38693
0.96487      -0.45876
1.27779      -0.53208
1.64641      -0.60760
2.18355      -0.70207
2.97130      -0.81745
4.00137      -0.93636
5.18395      -1.03412
6.40084      -1.09894
7.61722      -1.13687
8.83300      -1.15411
10.05898      -1.15441
11.31687      -1.13950
12.57946      -1.12474
13.84294      -1.10997
15.10513      -1.09521
16.36511      -1.08048
17.62370      -1.06566
18.88108      -1.05097
20.13777      -1.03618
21.39346      -1.02150
22.64824      -1.00674
23.90252      -0.99208
25.15671      -0.97732
26.41190      -0.96265
27.66828      -0.94787
28.92637      -0.93316
30.18585      -0.91834
31.44704      -0.90359
32.70942      -0.88883
33.97301      -0.87395
35.23750      -0.85917
36.50268      -0.84437
37.76807      -0.82947
39.03315      -0.81468
40.29724      -0.79979
41.55983      -0.78503
42.82011      -0.77029
44.07770      -0.75549
45.33208      -0.74084
46.58337      -0.72612
47.83135      -0.71154
49.07674      -0.69689
50.32072      -0.68227
51.56411      -0.66775
52.80859      -0.65311
54.05468      -0.63856
55.30296      -0.62388
56.55325      -0.60927
57.80543      -0.59454
59.05882      -0.57989
60.31320      -0.56513
61.56799      -0.55047
62.82307      -0.53570
64.07806      -0.52103
65.33294      -0.50627
66.58783      -0.49160
67.84301      -0.47683
69.09880      -0.46216
70.35548      -0.44737
71.61307      -0.43267
72.87176      -0.41795
74.13154      -0.40313
75.39243      -0.38838
76.65411      -0.37353
77.91640      -0.35877
79.17928      -0.34400
80.44257      -0.32913
81.70656      -0.31435
82.97104      -0.29946
84.23603      -0.28467
85.50082      -0.26988
86.76570      -0.25498
88.03078      -0.24019
89.29617      -0.22529
90.56116      -0.21050
91.82555      -0.19571
93.08903      -0.18083
94.35191      -0.16607
95.61450      -0.15130
96.87519      -0.13646
98.12077      -0.12192
99.30775      -0.10791
99.99160      -0.09991

***EDIT*** I missed the lower surface coordinates!... now fixed
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« Last Edit: Oct 6th, 2008 at 11:54am by JetPlaneFlyer »  

ScreenHunter_10_Oct__05_20_16.gif (Attachment deleted)
 
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tonymat
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F1B guy, but don't hold
that against me..

Posts: 428
Haliburton
Re: New world FAI hlg record!
Reply #39 - Oct 5th, 2008 at 1:02pm
 
Jetplane flyer,

Thanks for the co-ordinates!

Tmat
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