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Apr 19, 2018, 09:19 AM
G_T
G_T
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Discussion

F3F and F3B


Hi All,

I am considering at some point designing airfoils and reference wings for these categories. What I would need to do a good job is to get wing designs for some of the current state of the art top competitive planes, as well as some details on flight modes and speeds, configuration for turns, that sort of thing. That would provide a baseline. For all the other wings I've designed I have had that.

I would not release any designs sent to me. They would not be mine to release, after all. Additionally, I don't generally start from someone else's work and modify. I have always started clean. But it is the nature of the problem domain that the front part of most good foils tend to look mighty similar, at least for conventional foils.

I don't want any designs right now. I'm just trying to find out if it might be feasible. I get asked occasionally if I'm going to work on such wings.

Thanks,
Gerald
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Apr 20, 2018, 04:30 AM
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Vectorf3f's Avatar
Wohohoooo Great news Gerald! would be super to count with one of your designs in the F3F scene!
Apr 23, 2018, 07:49 AM
Registered User
Hi Gerald,

I sent you a message.

cheers
Erik
Apr 23, 2018, 11:01 AM
G_T
G_T
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Thread OP
Thanks Erik, I'll check my email when I get home.

I've freed up a little space in my PM box as it had gotten full again. I have received some good feedback on this subject via PM. Any method is fine!

Thanks,
Gerald
Apr 24, 2018, 10:17 AM
G_T
G_T
Registered User
Thread OP
Erik, I did not receive your message. Can you please send again?

Thanks,
Gerald
Apr 25, 2018, 06:28 AM
Registered User
Hej Gerald,

Instead of a message, you get the info here

http://www.spline.dk/spline-team.html

If the emails doesnt work, please contact me again. I have different emails for John and Jan.

Both Jan and John are also on facebook. Mark will know what you are doing

cheers

Erik
May 08, 2018, 09:46 AM
G_T
G_T
Registered User
Thread OP
Sorry, I've been swamped again. I haven't had time to do anything aero just recently. Erik, if I can get some breathing room I'll send some emails - even if I don't have time to do any work. It would be good to make contact.

Gerald
May 10, 2018, 12:13 AM
F5j -F3j-F3F - What to Fly?
Dale Thompson's Avatar
Quote:
Originally Posted by G_T
Hi All,

I am considering at some point designing airfoils and reference wings for these categories. What I would need to do a good job is to get wing designs for some of the current state of the art top competitive planes, as well as some details on flight modes and speeds, configuration for turns, that sort of thing. That would provide a baseline. For all the other wings I've designed I have had that.

I would not release any designs sent to me. They would not be mine to release, after all. Additionally, I don't generally start from someone else's work and modify. I have always started clean. But it is the nature of the problem domain that the front part of most good foils tend to look mighty similar, at least for conventional foils.

I don't want any designs right now. I'm just trying to find out if it might be feasible. I get asked occasionally if I'm going to work on such wings.

Thanks,
Gerald
Have you considered leveraging all your DLG foil work into a F5j design?
May 10, 2018, 12:37 AM
Everything’s A Compromise
Larrikin's Avatar
Hi Dale,

Unsolicited reply.

The Syner J wing, or iterations of it, is doing very well in F5J circles. (Sorry ... I had to)
Perhaps a little less camber for the lower anticipated wing loading and a slightly higher aspect ratio, but the Syner J wing is still very suited to F5J ... IMO.
My take on it is that G_T could spend another 100% in time for potential 2-3% THEORETICAL improvement.
Hardly worth the effort when one considers the quote relating to an aerodynamic advantage, ... "One stall and you've lost it all".

D.
Aug 10, 2018, 01:19 AM
Registered User
Hi Gerald!
Any progress with this? I have two F3F models which can help a bit in your design process... the Shinto F3F and the Pitbull 2.
Oct 16, 2018, 12:10 PM
Soaring with Eagles
billbabin's Avatar
Hey Gerald,
I have a question about an airfoil.
I tried to send a PM, but it you RC groups inbox is full.

Otherwise, could you send me your email to [email protected]?
Thank you!
Bill
May 13, 2019, 02:18 PM
Registered User
Hi Gerald (and others),
I'm still looking forward to GT's work when her gets the time.

In the mean time, does anybody have a suggestion for some airfoils (root to tip) for a vac. bagged F3B glider ano 2019? I saw my first F3B contest in more than 15 years and I think I'm hooked. The easy thing would be to build a MH32 equiped Cobra-ish glider. But is there info on something newer AND better for 2019 and homebuild when speaking of airfoils for the wing??

Perhaps a Supra wing with reduced span?!

Cheers
Erik
Last edited by erikdahlchriste; May 15, 2019 at 02:43 PM.
May 15, 2019, 09:09 PM
G_T
G_T
Registered User
Thread OP
Sorry folks I've been somewhat out of the designing loop for a year+ for the most part. I do figure to produce an F3F and F3B design at some point. I haven't gathered up any reference designs for comparisons so I haven't seen where the current state of the art might be (aka, don't quit until you can smoke it). I don't know whether beating existing designs would be easy or would be hard. My experience so far seems to be that the bigger the wing, the more designers have been relying on the span to give performance and quitting early on the design process. But I'll presume F3B wings are better designed! A challange might be fun.

For F3F a number of years ago, in comparison against what at that time was apparently one of the popular airfoils, the original Zone DLG wing suitably stretched looked like it might literally lap the competition at a bit lower wing loading. That wing was fast and flat in practice and kept energy well. But times move on. It was a quick and dirty test, lost among what must be a thousand other quick and dirty tests.

I'd expect that SynerJ isn't quite suitable as it is insufficiently optimized for the high speed end where one is deliberately flying in a shallow dive - F3B speed run or F3F in good conditions. It might do well for distance and for light wind but anyway it doesn't have the right set of optimizations. So I guarantee it would leave some potential perrformance on the table. I can't compare it myself against current F3B designs, because, I don't have any! I'd be interested in a comparison if someone else has a design. That at least would give me some useful info.

Supra with reduced span wouldn't be my choice, really. I think even SynerJ though not designed for it would likely be better overall. Supra ccertainly wasn't designed for it!

The original Zone that Phil and I made, when ballasted up with 5 ounces, would punch upwind in 50mph winds with no problems at all. That was the condition when we flew the prototype! We'd punch upwind, hook a little bubble, fly it downwind, rinse and repeat. The challange was not getting the plane flipped into your face when launching, and of course getting it on the ground and staying there long enough to get a couple hands on it! That plane had serious legs.

The original Synergy DLG wing could also punch upwind at low wing loading with impunity if one leaned on the elevator hard enough.

Both do better in practice than what one would expect from the analysis. Lacking anything else to go by, those would be two I'd be looking at as starting points for a new design. Scaled up and modified for the expected Reynolds numbers range, then tweaked out of all recognition... It would just give me the first iteration of thousands.

But of course it would be far better if I had one or more very competitive wing designs for comparison purposes. My usual rule of thumb when I'm not an expert in the category, is beat it at everything then all the bases are covered.

In a few weeks I might have time to start thinking about it. I'll have to judge my interest, honestly. It is a lot of work.

Gerald
May 16, 2019, 09:36 AM
Registered User
Dear Gerald

some rather recent information can be found here on the development of the Shinto: http://www.aer-o-tec.de/de/index.php...legung-des-f3f

no coo. of the airfoils, but at least some polars for comparing

also they have a new one...the Impuls with apparently a thinner airfoil: http://www.aer-o-tec.de/de/index.php/impulse/
even with windtunnel experiments

And then there is the perfection 1 and 2: http://www.f3j.com/precision.htm
a lot of information from the designers

As there went tremendous amount of work of highly skilled people with acess to ressources into the design og F3F and F3B planes (Benjamin Rodax, Philip Kolb, Max Steidle, Dirk Pflug, Stefan Eder, Stefan Fraundorfer, the Herrig Brothers and many more) I think the bar of developing something new is very very high. But ok, it is also fun to try.

Something to remember is that F3B especially is a combination of tasks, which means the concept of a plane as to be looked at holistically, which means several factors have be included: Some of the them are not so obvious, fx....you have to do three lauches in F3B per round..getting 20 meters higher at each might be much more worth than a airfoil with 2% less drag in speed alone. The plane has to withstand rather brute forces at launch...a very thin twisted wing might not be superiror in launch. Duration can be improved by just building light. In Duration you have other planes as thermal indicator....so maybe you should not focus so much on duration...... and so on. So in short F3B means gaining as much points as possible and that is not necassarily the same as having a high performance wing.

Historically airfoils went from the (nowadays) rahter thick RG15 airfoil to thinner ones (around 8) and the camber is between 1,4 to 1,6 (I guess). There is almost no rear- loading anymore and most airfoils have an underside, that remembers the MH31. The first Freestyler in some ways cleared the way for modern airfoils. Here is some information: http://www.agm-penig.de/ as fasr as I remember they used a MH31 underside and a SD 8000 on top because the SD was delivering a lot of lift (launch). And then they made their airfoils from there. Somewhere on the internet is the story. Airfoils, that look very good on Xfoil might also be too cautious designed - even the very nice SD7003 (which made the World Champion) disappeared rather fast, as it is not fast enough at higher Re and has also a little bit too much drag in distance.

Hope, that that leads you into the right direction.
May 17, 2019, 05:02 AM
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Hi Gerald,
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Erik


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