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Author Topic: F1N-150 for Cat II+ - with flaps or without?  (Read 1079 times)
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Tapio Linkosalo
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« on: September 13, 2018, 01:53:17 AM »

Planning of trying F1N-150 in November, in a 18 meter football hall. Should I plan to make a model with fixed wing and spiral climb, or go with flaps and bunt?
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Olbill
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« Reply #1 on: September 13, 2018, 07:40:30 AM »

Probably solid with Ishii airfoil if you've got some light balsa.
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Tapio Linkosalo
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« Reply #2 on: September 13, 2018, 10:48:37 AM »


Thx. Where can I find coordinated for the Ishii airfoil?

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Olbill
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« Reply #3 on: September 13, 2018, 11:16:40 AM »

I've lost the coordinates. Anyway I think he made the coordinates from the airfoil instead of vice versa. Here are drawings on a grid. Also a few of his Cat 2 F1N's.

He makes his wings by hand without templates. There are some YouTube videos of Ishii carving a wing but I can't find them right now. He says it takes him 2 hours to make a wing.

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Re: F1N-150 for Cat II+ - with flaps or without?
Re: F1N-150 for Cat II+ - with flaps or without?
Re: F1N-150 for Cat II+ - with flaps or without?
Re: F1N-150 for Cat II+ - with flaps or without?
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Tapio Linkosalo
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« Reply #4 on: September 14, 2018, 02:15:39 AM »

150mm wing should be faster to carve... :-) But anyways, the airfoil looks complicated. How much would the performance suffer if I tried some stanfoil'ish airfoil?

 
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Olbill
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« Reply #5 on: September 14, 2018, 07:55:26 AM »

Tapio
I apologize but I didn't see the 150 in your question. All the info I sent was for F1N. I have no experience with F1N-150. There are a lot of plans on the Facebook group "Everything about F1N".
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boca55
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« Reply #6 on: October 08, 2018, 07:25:43 AM »

I tried flaps on the F1n model, but it does not work well with the discus start. If the left flaps were fixed down, and the right flaps worked, it might be work.
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Tapio Linkosalo
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« Reply #7 on: November 26, 2018, 07:06:47 AM »


I'm confused now. F1N seems to be the indoor hand launch glider, whereas people use F1N-150 for the small catapult glider. Why is that? Is there an official class for the (unlimited) indoor CLG?

 
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Tapio Linkosalo
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« Reply #8 on: November 26, 2018, 07:21:04 AM »


For what it is worth, I built a small (150mm) CLG with depron flaps and 1mm carbon rod for fuselage. Tried to trim that for Cat I hall, but it made quite a vicious bunt. I fixed the roots (center section) of the flaps to tame things down. Helped a bit.

Then came the date for the Cat II (or a bit over, 18 meters) flying event. I did not have the time to built a completely new model, so I took off the wing from my old model and sanded a new one from 2mm depron. Started trimming that, and even with non-flapped wind the model still bunted! Tried to figure out what gives and suspected that the carbon rod for fuselage flexes. I added a balsa spine to the carbon to stiffen it a bit and be able to go on flying. This helped some, I was able to make launches that climbed in a spiral manner. But still, if I tried to add more power to reach the ceiling, the model made a slight bunt before climbing out. After some head scratching I decided to try out launching vertical, and managed to gain some decent height with very strange flight pattern: after initial vertical launch the model bunts to some 45 degree attitude, and by that time the speed has slowed down so that the model starts to climb in spiral. Take a look at the video Simo-Pekka shot:  https://www.youtube.com/watch?v=ELTdF0CzW1k

My plan is to try a stiffer (balsa-carbon) fuselage next. But also seems like a bending carbon fuselage could work for bunt in a similar manner as flexing flaps.

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USch
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« Reply #9 on: November 26, 2018, 07:44:08 AM »

It certainly is not a conventional climb, but even so it get's up to good height. Looks like under the ceiling. So what….
Maybe the glide is not really what they call "floating"?

Urs
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Tapio Linkosalo
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« Reply #10 on: November 26, 2018, 08:50:02 AM »

It still remained a few meters below the ceiling, so there would have been room for more. But, I could not launch it higher, as adding power just made the bunt deeper. So I need to figure out what causes the bunt and try to reduce that.

I think the reason for non-floating glide is that the model is too heavy. The wing weights 1.0 grams, did not weight the fuselage but I guess it is close to 2 grams AUW. But, this was my first model for the class (with second wing), so next one will be better!

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Olbill
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« Reply #11 on: November 26, 2018, 10:20:51 AM »

Something is flexing. It could be the stab or the wing or the fuse. (that pretty much covers all the possibilities). I'd look at the stab first because of all the wild changes of direction during the climb.

If I were trying to do a competitive F1N-150 I'd copy Igor Nišević's model. It seems to be the best one going right now. The plan is on Facebook.

I wouldn't expect a floating glide from an F1N-150 unless you can get a model under 1 gram. Even then it's not going to glide like a competitive F1N, although Igor is getting close to F1N times.

You asked about a class for larger CLG's. The only one I've heard of is F1N-300 and I think it's only flown in a few places. Mikhail Yashinskii has a picture on Facebook of an F1N-300. It's my impression (maybe wrong) that F1N-150 started out as a class for kids but adults have also found it interesting..
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« Reply #12 on: November 26, 2018, 03:38:15 PM »

Tapio's model is supposed to fly left-right pattern, but in my video it looks like the second, spiral part of the climb turns right?  Anyway, after about 50+ timed flights he managed to beat my best (25.5) by 0.4 seconds...  Angry I had a full balsa wing with stiff pine fuz, reached the roof nicely, but transition and consistency was bad.

Well, this is an addictive, difficult and therefore fun class! Bill, we absolutely want to see your WIF-150!

SPR
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Olbill
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« Reply #13 on: November 26, 2018, 04:07:57 PM »

I tried a scaled down WIF7 and it was definitely not the way to go. The wing area was too small. And I coudn't see it when I launched it.
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USch
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« Reply #14 on: November 26, 2018, 04:47:25 PM »

Hi Tapio,
I have no direct experience with 150mm CLG, during winter I do some CLG with 250-300mm span. Anyway my feeling is that a 1mm solid CFK rod is not stiff enough. I would either try with a carbon tube 1,5x1,0mm. Right, these weigh 2,0g/m and not 1,1g/m as the solid rod. But the tube has 0,5mm wall thickness which can easely sanded down to 0,15-0,2mm from the wing trailing edge to the back end.

Or a balsa stick, 1-1,5mm thickness, with carbon strips of 1x0,12 (0,16g/m) on each side.
These are all pultruded sections made by Maarten Van Dijk.

Urs
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Tapio Linkosalo
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« Reply #15 on: November 27, 2018, 07:35:58 AM »

I agree that the carbon rod is most likely to bend, and I plan to try carbon capped balsa fuselage instead. From the attached images you can see how I added a balsa strip on bottom of the carbon rod to add stiffness, and it reduced the amount that the model bunted under higher power launches.

On the other hand, it is interesting to find out that flexing carbon fuselage might be used to provide aeroelasticity. That stiffness might be also easier to adjust by adding or removing some balsa strips.

Currently the model weights 1.85 grams, so a considerable reduction is needed. The wing is around 1 gram, that only should be halved. Also lighter tail feathers would turn into less nose weight, to reduce weight and ease stability.
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Re: F1N-150 for Cat II+ - with flaps or without?
Re: F1N-150 for Cat II+ - with flaps or without?
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USch
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« Reply #16 on: November 27, 2018, 08:24:53 AM »

That looks like a full-wing out of Roofmate and no flaps? Can you show us how il looks like taken from the underside as in pic 2 but with the whole wing cord showing?

Sure, I am curious and will build one for the next indoor flying session in January just for fun  Cheesy

Urs
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Tapio Linkosalo
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« Reply #17 on: November 27, 2018, 09:02:27 AM »

It is not roofmate, but some green-ish 3mm depron that I bought from Bauhaus several years ago. The bottom is flat and has the "skin" still on (yes I know it adds to the weight), and the top is sanded to typical airfoil shape. I did try to kink a bit flap to the trailing edge to reduce bunt, but then bent it back to flat underside. Indeed the wing is so thick that there is no flexing flap effect, unless the whole wing bends at tips (which I doubt). I bent the tips a bit to introduce the rolling moment to right. I'll take another pic later tonight.
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Skymon
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« Reply #18 on: November 28, 2018, 03:00:46 AM »

A lower aspect ratio and more steeply raked stab might help the flexing.
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Tapio Linkosalo
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« Reply #19 on: November 28, 2018, 04:09:23 AM »


Bottom/side view of the wing. I glued a strip of balsa to the bottom of the wing for easy gluing (cyano) to the wing saddle. The wing is attached to the fuselage also at the trailing edge, but this is mostly to stiffen the fuselage rather than solidifying the wing. The picture also shows the balsa strip to stiffen the fuselage. Note left wing tip bent up for aileron effect (the right tip is bent down) - the model is aimed for left-right flight pattern.
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Re: F1N-150 for Cat II+ - with flaps or without?
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Olbill
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« Reply #20 on: November 28, 2018, 09:30:48 AM »

There's an awful lot of incidence in the wing. Have you done tests to establish the correct decalage?
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Tapio Linkosalo
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« Reply #21 on: November 29, 2018, 02:26:54 AM »


No, I did not do such tests. How do you do them?

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adanjo
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« Reply #22 on: November 29, 2018, 03:13:33 AM »


I'm confused now. F1N seems to be the indoor hand launch glider, whereas people use F1N-150 for the small catapult glider. Why is that? Is there an official class for the (unlimited) indoor CLG?

 

I think the name 'F1N-150' is inadequate because F1N is the name of the official FAI event.
I had ever recomended east europeans to change the name and not to use the name of F1N-XXX.
But regrettably they still keep on using the name.
Aki
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Olbill
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« Reply #23 on: November 29, 2018, 09:32:55 AM »

http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=23576.msg233907#new
Reply 59.
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Tapio Linkosalo
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« Reply #24 on: November 29, 2018, 11:42:33 PM »


I think the name 'F1N-150' is inadequate because F1N is the name of the official FAI event.
I had ever recomended east europeans to change the name and not to use the name of F1N-XXX.
But regrettably they still keep on using the name.
Aki

Quite right, Aki-san! Especially as F1N is a hand launch glider, and the 150mm span model is a catapult one.

So maybe we should call it CLG-150.



 
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