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F1N glider development in Europe (Read 7739 times)
tonymat
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F1N glider development in Europe
Nov 26th, 2009 at 4:17pm
 
Found this interesting forum about some very cool and interesting low ceiling F1N hand launch gliders (indoor) being done in Europe (Croatia and Poland). http://www.aeromodelarstvo.net/Forum/forums/thread-view.asp?tid=10&start=46
The models look fantastic! Cool

Tmat
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staubkorb
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Re: F1N glider development in Europe
Reply #1 - Nov 26th, 2009 at 5:05pm
 
That Krila airfoil on the bottom of page 5 really floored me!  Sharp entry, FLAT rise to the high-point and flat to the flap.

Pete
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tonymat
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Re: F1N glider development in Europe
Reply #2 - Nov 26th, 2009 at 7:36pm
 
Yes it IS very interesting isn't it?
Work being done right now on that sort of entry and the results are , well, interesting!...

Tmat
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Randy_Reynolds
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Re: F1N glider development in Europe
Reply #3 - Nov 26th, 2009 at 8:19pm
 
Yes, It's beautiful work and the glider in the video was flying slowly which is hard to do unless you have Obill's skill for lightness.  9.3 grams is pretty heavy for a flapper.

I wonder how the carbon tissue is applied.  That's nicely done.
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olbill
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Re: F1N glider development in Europe
Reply #4 - Nov 26th, 2009 at 9:41pm
 
Some points about the airfoil and F1N models:

The airfoil is similar to the triangular foils that were being used when I was flying HLG in the late fifties. I think Curt Stevens has some discussion of that type of airfoil on his website. One difference is that the high point seems to be further forward than what I remember. There are a couple of obvious advantages over "normal" airfoils - there's a lot less wood  (=weight) and they are easy to make.

A lot of different airfoils are used on indoor rubber duration models without much effect on performance. It could be that the low Re of Cat 1 gliders might produce unexpected results from any given airfoil. It sounds like some experiments might be in order. I'm planning to build a Cat 1 TLG since my shoulder is too messed up to do a javeline throw anymore. This might be a quick way to get one in the air.

The times being done by these gliders are good but not earth shaking. I couldn't figure out the ceiling heights. The current Cat 1 F1N record is 49.8 seconds which is a LOT more than 40 seconds. (trust me on this)

I tried carbon tissue a number of years ago and still have a bunch of it in the closet. I really couldn't tell that it accomplished anything but this could be just a case of not doing it right.
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« Last Edit: Nov 26th, 2009 at 9:42pm by olbill »  
 
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Re: F1N glider development in Europe
Reply #5 - Nov 27th, 2009 at 2:48am
 
I was aware of the triangular airfoils and some of the reasoning behind them.  There were even a number of rc and CL models in the late '60s that used a symetrical section - not a curve anywhere.  We even had a short discussion on them back when I was studying aircraft design in the late '60s.

Olbill: The carbon tissue goes on quite well with Nitrate.  Better is a very thin laminating epoxy.  The trick is wetting  the tissue thoroughly andmaking sure that it is laying on the base and NOT floating.  VERY thin and very light, when done properly imparting that "just enough" strength/ding resistance to do the job.  If you ever decide to part with the carbon tissue, let me know.

Pete
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dlaka
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Re: F1N glider development in Europe
Reply #6 - Nov 30th, 2009 at 12:54pm
 
Hello everyone, from Croatia

We started with Indoor HLG around 3 or 4 years ago. The goal we had set to us was to have plenty of contestants, especially children. And since then we have certainly met that goal.
We fly 2 categories:
F1N-150 catapult (national category with max wingspan 150 mm)
F1N
We have an annual National competition and 6 for the Croatian cup, where we consider 4 better results for the final placement. This years cup had over 120 contestants in F1N-150 and around 60 in F1N. All the competitions are in halls in the height range of 8 to 9 meters.
The model that I use now, F1N (No.16) has a wingspan of 644 mm and weighs 7.9 grams. The fuselage is MaartenVan Dijk (http://www.dpp-pultrusion.com/en/index.html) 2/1 mm carbon pultusion microtube (thinned to a.1,5 mm towards the tail)
The longest official flight was measured 44.2 sec in a 8 meter high hall.

Carbon tissue was just an attempt of mine on witch I gave up. To harden the wings I now use Maarten carbon thin strips 3 x 0,13

Damir
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JonSayre
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Re: F1N glider development in Europe
Reply #7 - Nov 30th, 2009 at 1:28pm
 
Dlaka, sounds like you folks have a great competition! Do you order directly from Dijk or from a supplier? I am interested in purchasing some of those tubes. Please post some pictures of your models if you can I am sure we would love to see them.

Edited to say that I have found the distributor in the USA. https://www.a2zcorp.us/store/Category.asp?Cguid={566C7CBC-715E-4C24-9B1A-344592C...
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« Last Edit: Nov 30th, 2009 at 1:31pm by JonSayre »  
 
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Re: F1N glider development in Europe
Reply #8 - Nov 30th, 2009 at 1:43pm
 
Relating to this.

   I tried cutting some very thin cores for a Cat.1 glider from foam and got mediocre results. I first tried 25PSI pink foam and then Hi-load 60. The HL-60 had a nicer surface but was heavier the pink foam was really light but rough. Both were too wavy to be used. I think maybe the pink foam with a thicker tip foil might work but would require lots of carbon probably in a disser arrangement.
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olbill
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Re: F1N glider development in Europe
Reply #9 - Nov 30th, 2009 at 5:07pm
 
JonSayre wrote on Nov 30th, 2009 at 1:28pm:
I am interested in purchasing some of those tubes. Please post some pictures of your models if you


Jon
IMO the pultruded tubes have a couple of drawbacks for low ceiling gliders. The main problem is weight. I think a full length tube for a Slow Poker sized glider will probably weigh close to 2 grams where 1 gram would be more appropriate. Stan says his is .6g. Maybe Dlaka's sanding of the boom would get the weight to a more reasonable number - but that brings up problem #2. Pultruded tubes have all of the fibers going in the long direction. This makes splitting the tubes a very real possibility in any circumstance that puts a big bending load on the tube - like a crash.

Dlaka
Your 44.2 second time with a 7.9g glider is very impressive! I think the best I ever did with HLG was about 41. Have you tried the same glider at a lower weight?
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dlaka
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Re: F1N glider development in Europe
Reply #10 - Dec 4th, 2009 at 7:05am
 
Sanded pultruded fuselage weighs 1.6 gram. So far I didn´t broke them. The only problem is that they may be a bit too elastic.

I tried with lighter models too, but unfortunately they didn´t survive. The last model, No. 21 is 7.4 gram, fuselage is from russian carbon tube D 3 mm and 1.1 gram weight (for F1B stab). It seemed a lot better than 16, but unfortunately the stab broke on the first official flight.
I would say that for a long flight in a low height hall a good transition as close as possible to the sealing is the most important.
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« Last Edit: Dec 4th, 2009 at 2:26pm by dlaka »  

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dlaka
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Re: F1N glider development in Europe
Reply #11 - Dec 4th, 2009 at 7:07am
 
No 16 & 20
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dlaka
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Re: F1N glider development in Europe
Reply #12 - Dec 4th, 2009 at 7:07am
 
No 16
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tonymat
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Re: F1N glider development in Europe
Reply #13 - Dec 4th, 2009 at 8:58am
 
Very pretty airplanes Dlaka!
Mark Drela's Upstart gliders used some carbon fiber tows top and bottom of the stabilizer to prevent folding on launch.
Why did you make your stabilizer with opposite dihedral (Anhedral)?

Tony
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olbill
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Re: F1N glider development in Europe
Reply #14 - Dec 4th, 2009 at 9:39am
 
dlaka wrote on Dec 4th, 2009 at 7:05am:
Sanded pultruded fuselage weighs 1.6 gram. So far I didn´t brake them. The only problem is that they may be a bit too elastic.


Dlaka
Your models look very nice!

My current Slow Poker (built for catapult launch) uses a balsa fuselage with .003" carbon laminate both sides. It's 21" long and weighs about 1 gram. The carbon is put on with thinned Duco glue. I have another similar one with the carbon put on with epoxy that is a little heavier. These fuselages will break on a dive into the floor but are easy to fix with thin CyA glue.
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dlaka
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Re: F1N glider development in Europe
Reply #15 - Dec 4th, 2009 at 2:09pm
 
Tony
That is top secret Smiley

For firmness, so that the tube doesn’t have to go till the end. And it looks nice.

olbill
I tried with balsa fuselage strengthened with boron and wrapped in Kevlar. Maybe I’ll try again

Damir
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« Last Edit: Dec 4th, 2009 at 2:18pm by dlaka »  

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olbill
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Re: F1N glider development in Europe
Reply #16 - Dec 4th, 2009 at 3:48pm
 
Most people here don't like to see boron on gliders. The feeling is that when a glider crashes it can leave splinters of boron on the floor that could injure other users of the area. Boron isn't illegal for gliders but I would not use it for this reason.

I have a new low ceiling catapult glider under construction now but haven't decided on the fuselage construction yet. It will probably be balsa with some form of carbon on either 2 or 4 sides. I have some super epoxy that Tony talked me into buying so may try that with either carbon laminate or carbon tow.

I like the anhedral stab!
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Re: F1N glider development in Europe
Reply #17 - Dec 4th, 2009 at 4:30pm
 
Dlaka, those gliders look great! I like the signature it is a nice touch. Cool If you can afford 1.5 grams for your boom you should be able to build a pretty robust balsa/carbon fuselage. But I don't know if it would be any better than the carbon tubes you use.
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tonymat
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Re: F1N glider development in Europe
Reply #18 - Dec 4th, 2009 at 8:31pm
 
One possible benefit to anhedral on the stabilizer is that it effectively puts the stab below the wing wash. And as Damir said, it does add a bit of stiffness from the dihedral joint. This would also add a tiny bit of extra weight though. But it does look cool. Cool

It may be possible to make the fuselage lighter from the balsa/carbon sandwich than possible with the carbon tube.

Tony
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olbill
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Re: F1N glider development in Europe
Reply #19 - Dec 4th, 2009 at 11:06pm
 
tonymat wrote on Dec 4th, 2009 at 8:31pm:
This would also add a tiny bit of extra weight though. But it does look cool. Cool
Tony


If he glued it together with Duco it didn't add any weight. Duco is weightless. (well almost).

Seriously - I just glued 4 - 3" strips of carbon tow to my catapult stab with 2 coats of thinned Duco and the weight gain was 10mg for the tow and glue!
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