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Author Topic: F1N question  (Read 3765 times)
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cglynn
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« on: December 10, 2018, 12:18:46 PM »

If an individual were to throw his glider left handed, would left-left be the preferred (or easiest) way to get a reliable launch and transition?

I tried my first semi serious F1N over the weekend (Yashinskiy plan, overweight at 10.5g.  Flaps were from 1/8" blue insulation foam sanded to approx. .030" at the TE) , and initially set up the model for fly right-right, as that is what I would do for clg.  This did not work nearly as well for me with the HLG.  I thought that the right rudder would cause a right roll, so launched the model banked left.  The model wanted to pull to the left, and also roll left, which was puzzling.  It took the first launch of the model, and the subsequent roll to inverted and crash, for me to rethink my launch strategy.  So then I was trying to launch by throwing overhand/overhead, with right bank (45 degree bank, 45 degree inclination) which worked some of the time and resulted in a low launch but a decent flop into glide.  More often than not however, the model would roll prematurely to the left, basically stop mid air, and then with no forward momentum and the associated stall, drop the nose and dive into the floor.  An observer noticed that maybe I was flicking my wrist before release and that was causing the left roll.  Eventually, I crashed the model which broke the fuse and/or the pylon a few too many times, so decided to call it a day.

I went home and looked into some F1N videos and noticed that most fliers are flying in the direction of the hand they launch with, so I want to try that for the next time out.  My initial thoughts are to use left rudder, and stabilizer tilt for the glide turn.  What I can't wrap my mind around is how this trim will work for launching.  Intuition tells me that the left rudder, along with left bank at launch would compound and cause a severe left roll.  Or is the launch speed low enough that the trim settings don't have the same effects as in a CLG?  Or is the key to launch to use no rudder offset/warp, and just use stab tilt to influence the glide turn?  Lastly, for flaps, I am assuming thinner is better, as long as they are strong enough.  Would flaps that are too thick, too strong, and too springy be causing that sudden stop at the top?

Thanks in advance for any suggestions/advice. 
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Maxout
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« Reply #1 on: December 10, 2018, 01:19:53 PM »

Ok...so your launching left handed...

I throw my Yashinsky right handed and I've got enough washin on the right wing that it doesn't roll at all on the way up. Launch at 45 deg bank, 60 deg nose up, and it slides right into the right hand glide. Don't wash in the tips. You need to twist the washin into the wing just an inch or so outboard of the wing root.
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USch
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« Reply #2 on: December 10, 2018, 01:48:01 PM »

You dont mention any wing warp. More important than rudder setting.

I myself are (or better did) throwing lefthanded with right wing forward section washed IN. Launch was with very small banking angle to the left, overhead and rolling slightly to the right. Actually the best height and transition was with nearly straight up climb, no rolling I mean, and bunting right under the ceiling. Glide was to the right. Of course I talk about class I ceiling with 7-8m max height.

Initial trimming was with the wing pylon fixed by two small pieces of tape and throwing horizontally, adjusting till the model tracked straight and pulled just a little bit up at the end of the heave.

Urs
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cglynn
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« Reply #3 on: December 10, 2018, 02:05:33 PM »

Thanks Josh.  So to double check:  Wash in only the root, then I assume let the wash in transition to nothing near the wing tip.  Wash in the inboard wing more than the outboard wing (yes/no?).  Still use rudder deflection and stab tilt for the turn?

Urs, I wonder if my flaps were built too stiff, causing a premature bunt to stall type transition?  If I could get the model to launch near straight up, then bunt into glide, I would definitely do it.  I think in order to do that though, I am going to have to spend some more time sanding my foam.  .030" (.76mm) thick at the TE seems too stout to be useful.

~CG
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USch
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« Reply #4 on: December 10, 2018, 02:40:12 PM »

CG, check the flap stiffness blowing slightly from the leading edge and looking if the flaps move up or not.
Also the initial trimming procedure shows if they are to stiff. If the model pull's up after a short, horizontal distance, then you have to take out the sanding block  Grin and do the homework  Roll Eyes

Personally I never did floam flaps, the expert on the argument is Bill Gowen (Oldbill).

Urs
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Olbill
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« Reply #5 on: December 10, 2018, 05:24:01 PM »

If an individual were to throw his glider left handed, would left-left be the preferred (or easiest) way to get a reliable launch and transition?


I've started to try to answer this a couple of times but there are too many issues for me to try to nail down an answer.

For instance here is just a smattering of info about your first question:

Normal pattern for a left hand sidearm throw would be right climb and left glide (if the flying site is large enough). For a smaller site R-R or L-L could be used.

For a left handed baseball throw, L-L would be sort of normal for me if I were left handed. Stan would tell you R-R based on his Slow Poker article.

For a left handed vertical underhand throw, the glider top or bottom could be facing your body and the climb could be in either direction. For the most usual way of doing this throw, the top of the glider would face your body (throw from the left wing) and the climb and glide would be to the left.

IMHO the first thing to do is build a glider based on your flying site and get it set up with correct incidence. Then you can start applying trim and launch techniques based on the site and on your physical capabilities.

I think you should join the "Everything About F1N" Facebook group and spend some time doing research. Find someone whose techniques make sense to you and then follow whatever they have to say about model setup and launch methods.
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cglynn
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« Reply #6 on: December 10, 2018, 10:41:42 PM »

Thanks Bill. 

I will have to check out the F1N FB group.  I have been avoiding social media for the past few years, but should probably give it a look.

Based on my limited experience with indoor HLG’s, baseball style throw has proven to be most comfortable, so I will be going that route, and setting up a model for left-left.  Seems like a good place to start.
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Skymon
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« Reply #7 on: December 13, 2018, 11:48:23 AM »

It's worth just looking as a viewer, I believe it's a public group.
There is a lot of info in that group - videos, plans, discussion, etc.
Well worth a view.

Regards
Si
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cglynn
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« Reply #8 on: December 16, 2018, 03:26:24 PM »

Ok, so I haven’t hoped in FB to check out the F1N group yet.  I need to set up a new account as the group will not allow non-FB members to view content.  It’s on my to do list though.

What I have been doing is looking at just about every low ceiling F1N flight I can find on the web.  Finally, the trim setup became apparent.  I am used to outdoor CLG where I set up my models to fly opposite the bank on launch.  Being left handed, I setup my CLG’s to launch with left bank, and circle right with right rudder, stab tilt, and a wash in wedge on the starboard wing.  I was trying the same sort of thing for F1N which (as most likely everyone else in the world of F1N already knows) doesn’t work for squat.  My guess is that in low ceiling F1N, the launch speeds are no where near that of an outdoor CLG, so the rudder does not have nearly as much authority.

It appears that in F1N (and other IHLG flying) rudder in the direction of bank works because of the near vertical inclination at launch.  From what I have seen is that by time the rudder starts to cause a rotation, the model is already near the ceiling.  The rudder is causing the nose to drop to level, putting the model into a knife edge orientation.  At this point, due to the dihedral in the wings, and the complete lack of fuse area, the model side slips into a stable, upright orientation at glide speed.

At any rate, that’s what I think is happening at launch and transition.  I am just putting that out there for confirmation or criticism of that idea, as knowing how the model is supposed to behave helps me build and gives me an idea of how to start trimming.  So if I missed anything, or am totally wrong about this handlaunch stuff (wrt an overhead baseball style throw) feel free to let me know.

Thanks all
CG

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Olbill
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« Reply #9 on: December 16, 2018, 05:37:15 PM »

I fly a Yashinskiy TIT as a CLG. Yesterday I had a string of several 40+ flights at St. Lukes. There's a crude video of one of them on FB. In order to turn this large glider in a small room I used a lot of left rudder, 90 degree right bank, and an almost vertical launch. (I'm right handed). I used a very soft launch that got the glider up to about 25' so it could be gliding when it passed under the 22'-11" wall on the opposite side of the high channel. I think this glider could easily hit the mid forties in a more wide open Cat 1 site with an 8 meter ceiling.

Note that European fliers are doing mid-fifties with this glider in low Cat 2 sites around 12 meters.
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cglynn
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« Reply #10 on: December 16, 2018, 06:01:07 PM »

Bill, how does the TIT look for a Cat II UCLG?  If you are doing mid 40’s under 25 feet at St Luke’s, it seems like you could do some serious time at the Kent Field House.  And at 7+ grams, that’s enough to get to the ceiling there, right?

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Olbill
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« Reply #11 on: December 17, 2018, 12:40:31 AM »

Chris
I never got to the ceiling at Rantoul with 7g TIT and there was some kind of problem with my heavier one that I couldn't figure out before I broke it.

I would guess the 7g model would probably climb 40' or so and do in the 50+ second range. I hope when I get the heavy one fixed it will do better than that. And I just inherited another kit that I'll be building.

My big question is whether I will go again in 2019. I hope I can.
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cglynn
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« Reply #12 on: December 17, 2018, 03:07:24 PM »

Bill, sure hope you are able to make Kent this year.  Due to the holiday, it looks like I will only be able to make Saturday, but its better than nothing. 

Also, I was thinking about what you posted about your launch trim and angles on the Yashinsky model.  Even though its being propelled by a catapult, it seems to be really similar to the underhand fling I see European pilots using.  They just whip that thing straight into the air, and it flies great.  Also makes me wonder if I was launching too shallow, trying to "fly" the model through the transition (like Damir's DK29) as opposed to letting it flop in, as I see this model doing.  Though I also saw on your post on FB that shows how the Yashinskiy model can be launched a number of ways, and still manage to transition well.


That said, for my next attempt at IHLG/F1N, I put together a modified Upstart 4 over the weekend.  It was built directly from the outlines in Gitlow's book, which happens to be about 94% actual size, because I forgot to enlarge the plan to make the scale reference the correct size (D'oh!)  Instead of wood for the flaps I used blue insulation foam that was resawn on a band saw and sanded to the appropriate thickness.  I also beefed up the nose portion of the fuse with some carbon tow, as it seemed a little flimsy.  All said and done, it came out to 4.5g, which I was very happy about--A 94% airframe that is 81% of the fullsize weight.  Now, with luck I can throw it to altitude and get a decent transition.  Next flying session is in a few weeks, so we will how it goes.

In the meantime, I am going to dig out my little Hang 10 glider and chuck it outside for some practice.  My arm/back/legs could use the workout.

CG


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Olbill
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« Reply #13 on: December 17, 2018, 04:47:59 PM »

Chris
Stan told me he thought the underhand throw was the same as a catapult launch but I'll have to disagree. If you throw a model by the wingtip the model will be rotating about its CG at the moment of release. If you look at a lot of discus launch photos you'll often see the tailboom bending inward just after release. That's b/c the rudder or y-tail is what stops the rotation after launch. For a right hand discus launch the model will be trying to rotate counter clockwise when it's released. The tail stops the rotation and the result is the boom is bent to the left.

So for a vertical wingtip launch the same thing is happening but in a different plane. For a catapult launch there is no rotation.

In the early days of DLG a lot of people thought this was a ridiculous idea but I think it is accepted as true these days. I used to tell people to try throwing a stick with a discus launch and see if they could do it where the stick didn't rotate after release. It's pretty much impossible to do that.
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cglynn
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« Reply #14 on: December 17, 2018, 06:55:53 PM »

Bill, I definitely know what you mean about the discus launch.  I built an RC 1.2m DLG a few years ago.  The first tailboom was not strong enough, and on a decent throw it snapped.   The wing did some how do we say “interesting” things as it became rapidly unstabilized. A stronger boom and a few other repairs were required, and since then it has flown about as well as I can fly it.

What I was getting at with the comparison is that I can envision the trim settings being similar for the underhand fling as well as the discus launch.  So maybe a more fair comparison would be to specify that after the boom stabilizes (so maybe 3-5 feet after release?) the two launches are similar.

Of course on the other hand, I am sure that the initial boom deflection during and immediately following launch would almost certainly have to have some effect on the model, if only for a few milliseconds or so. 

I personally don’t see myself utilizing the underhand fling on my low ceiling gliders.  It seems to me that an overhead throw imparts far less rotational forces on the tail, and as such, the boom does not need to be as strong.  This of course means it can be built lighter.  For my next F1N, I am going to use the same fuse construction I used on the Upstart.  I have a very nice piece of 5lb/cu ft C grain .070” that gets carbon tow laminated to each side, and the top and bottom in front of the wing, using thinned Duco as the adhesive.  This resulted in the fuse on my upstart weighing 25mg per inch.  The fuse on the F1N I have on the board works out to be 20 inches, so at that weight, right around 500mg.  Even with some extra carbon, as may be needed due to the increased length, I am fairly confident I can build the fuse under 700 mg.  This just over half the weight of the TIT fuse, with a reduction in strength.  But I will gladly trade that strength for a weight savings, if the strength is not needed. 

CG
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dslusarc
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« Reply #15 on: January 05, 2019, 11:15:09 PM »

Chris,

Bringing my Yashinsky F1N to the gym tomorrow, I built the kit today.

Don
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