Dreamflight Ahi aerobatic glider - Page 109 - RC Groups
Thread Tools
Dec 07, 2017, 04:31 PM
Piscine Promulgator
surfimp's Avatar
Quote:
Originally Posted by ceyak
snap flaps = " i understood that snap-flaps add in a bit of camber/reflex to augment/enhance your elevator throws"

dynamic flaps = "the opposing mix where you augment your camber/reflex throws with a bit of elevator with the goal of offsetting the tendency for the nose to raise (camber) or drop (reflex)"

sorry, is that not just what @surfimp said?
Yep, although my point was that tendencies for the nose to pitch up or down will vary from one airplane design to another. It's not set in stone for all planes, all times, all people.

To Dawson's larger point: every airplane design is different, and what's a "normal" response for one design may be totally different on another. The way to really learn this stuff is not to theorize at one's keyboard, but to get out on the slope and fly, testing different things out, seeing how they respond, and adding practical experience to inform and improve (and sometimes disprove) one's theories.
Sign up now
to remove ads between posts
Dec 07, 2017, 05:31 PM
Registered User
Quote:
Originally Posted by surfimp
To Dawson's larger point: every airplane design is different, and what's a "normal" response for one design may be totally different on another. The way to really learn this stuff is not to theorize at one's keyboard, but to get out on the slope and fly, testing different things out, seeing how they respond, and adding practical experience to inform and improve (and sometimes disprove) one's theories.
sure folks, i think most people would agree with the notion that doing is generally more fruitful than talking. that said, this is a forum, so the medium is talking. there's also a difference between theorizing - which can be aimless - and communicated learning which can help when trying to develop a conceptual grasp or mental model of something new.. personally, i find that helpful and it's probably why a good many folks are here in the first place. juss sayin'
Dec 07, 2017, 06:16 PM
Registered User
racedouge1's Avatar
Damn...Next time I'll check to see if the gun is loaded before I shoot myself.
Dec 07, 2017, 09:25 PM
PGR
PGR
Low AltiDude
PGR's Avatar
Quote:
Originally Posted by racedouge1
Damn...Next time I'll check to see if the gun is loaded before I shoot myself.
Not sure why, but this reminded me of a hangover I had once... It was so bad that I was ready to shoot myself, but I chickened out 'cause I was afraid the noise would kill me before the bullet could do it's thing.

Yeah, really.

Pete
Dec 08, 2017, 11:53 AM
Phil.T-tailer
Phil.Taylor's Avatar
Quote:
Originally Posted by ceyak
sure folks, i think most people would agree with the notion that doing is generally more fruitful than talking. that said, this is a forum, so the medium is talking. there's also a difference between theorizing - which can be aimless - and communicated learning which can help when trying to develop a conceptual grasp or mental model of something new.. personally, i find that helpful and it's probably why a good many folks are here in the first place. juss sayin'
Something new? - hardly - coupled flaps have been used for a very very very long time on U-control / control-line stunt planes - in fact, after a bit of googling, since 1949

https://encrypted.google.com/patents/US2611213

Phil.
still dizzy after all these years

and - to me the Ahi really reminds me of the control-line stunters - size & shape - just need to shorten the tail a bit
Dec 08, 2017, 12:32 PM
aka: Scott Ellis
Xeric's Avatar
Quote:
Originally Posted by Phil.Taylor
Something new? - hardly - coupled flaps have been used for a very very very long time on U-control / control-line stunt planes - in fact, after a bit of googling, since 1949

https://encrypted.google.com/patents/US2611213

Phil.
still dizzy after all these years

and - to me the Ahi really reminds me of the control-line stunters - size & shape - just need to shorten the tail a bit
You know, with the right site and if you were crazy enough really wanted to, you could probably do control-line dynamic soaring . . .
Dec 08, 2017, 01:14 PM
Phil.T-tailer
Phil.Taylor's Avatar
Quote:
Originally Posted by Xeric
You know, with the right site and if you were crazy enough really wanted to, you could probably do control-line dynamic soaring . . .
Continuous circles (dizzy!) - or figure of 8s?
Actually, many years ago I saw a guy doing continuous figure of 8s after the engine cut - on a flat field site - 8s on the downwind side, up & into the wind & back around, upright & inverted. Ok - so he was whipping-it a bit, but maybe actually DSing the wind gradient?

(sorry listeners - normal Ahi flap pitch arguments will resume shortly...)

Phil.
Dec 08, 2017, 05:10 PM
Phil.T-tailer
Phil.Taylor's Avatar
Quote:
Originally Posted by racedouge1
Why are snap flaps the most misunderstood thing...?
Because for most flying, they are mostly irrelevant

If you fly F3F & want really tight turns without losing speed, or you fly aerobatics & you want really square corners in your square loops - then they have a purpose. Don't fly F3F? - Don't fly square corners? - Don't need snap flap! (trust me...)

Understanding? - Explanation? - snap flaps are there to increase the maximum lift coefficient that an airfoil will produce, before the drag increases too much & the airfoil stalls - that's all there is too it. For F3F - its an obsession. For control-line stunters - its all about the nice square corners - and has been since the 1950s.

Phil.
YMMV etc etc
Dec 08, 2017, 08:25 PM
Registered User
Quote:
Originally Posted by Phil.Taylor
Something new? - hardly - coupled flaps have been used for a very very very long time on U-control / control-line stunt planes - in fact, after a bit of googling, since 1949
'course @Phil - i was saying new to me.
Dec 09, 2017, 12:09 PM
Piscine Promulgator
surfimp's Avatar
Quote:
Originally Posted by Phil.Taylor
Because for most flying, they are mostly irrelevant

If you fly F3F & want really tight turns without losing speed, or you fly aerobatics & you want really square corners in your square loops - then they have a purpose. Don't fly F3F? - Don't fly square corners? - Don't need snap flap! (trust me...)

Understanding? - Explanation? - snap flaps are there to increase the maximum lift coefficient that an airfoil will produce, before the drag increases too much & the airfoil stalls - that's all there is too it. For F3F - its an obsession. For control-line stunters - its all about the nice square corners - and has been since the 1950s.
I disagree that snapflaps are irrelevant... a small amount of snapflaps noticeably improve the outside / inverted performance of the Ahi, and they're pretty mandatory for gliders with fully symmetrical wing sections designed for their use (i.e. MG05, TP42, TP29, etc.)

Snapflaps also improve your maneuverability for very low altitude VTPR moves (especially when augmented by dynamic flaps aka 4 axis).

But don't take my word for it... try flying your plane with and without and see if you can tell the difference.
If you can't, then Phil's statement is correct

For my part, I would certainly notice.
Last edited by surfimp; Dec 09, 2017 at 12:19 PM.
Dec 09, 2017, 02:11 PM
Phil.T-tailer
Phil.Taylor's Avatar
Quote:
Originally Posted by surfimp
I disagree that snapflaps are irrelevant... a small amount of snapflaps noticeably improve the outside / inverted performance of the Ahi, and they're pretty mandatory for gliders with fully symmetrical wing sections designed for their use (i.e. MG05, TP42, TP29, etc.)
LOL - Steve - that's cos you are way beyond "most flying"(*) & well into the land of serious aerobatics

outside/inverted - same difference - bigger minimum (max -ve!) Cl before the drag goes up to much & "outside" stall - certainly helps Ahi outside loops, but not sure the Ahi will actually do decent outside square loops - now theres a challenge

(* most flying - a few rolls, loops, pumps, bit of inverted - the stuff that's in most flying videos - except Steve's )

Phil.
Dec 09, 2017, 02:18 PM
Piscine Promulgator
surfimp's Avatar
Well, thanks Phil, but I'm just another JoeSixpack with a penchant for toy airplanes and a love of fresh air and beautiful scenery, just like the rest of us

But you raise a good point: the Ahi does fly quite well without any special mixing at all. Dieter from Germany flies his quite successfully that way. It's really down to the pilot and the prevailing lift conditions.

I guess, as always, I am just trying to share what I've learned, and what works for me. My flying style and setup have evolved together to suite my local lift situation and flying sites, just like everyone. Although Ellwood is a cliff, it's a small one, and the wind is light, so we've got to have every advantage we can get, to do the most we can with the conditions. The fact that we can fly this way at all is still like a dream to me!
Dec 09, 2017, 03:38 PM
Registered User
minirotor's Avatar
Yep....as Steve says-depends on yoursite/experiance/etc.
I use lots of pos/neg flap for various reasons to push the limits of normal flying.
But if you still coming to terms with normal flying they're not neccessary.
But-they do give tighter loops (inside & outside)partically outside with less speed needed.
Also a lot of neg flap and full up elevator id good for landing in a tight spot (thats a proplem for where we fly).
A little neg flap also helps you get back out front of ridge again if you drift a little too far back and low down.
A little pos flap helps get high again in light wind conditions.
Oh-and makes for a nice flater spin.
Mine spin really fast to the right-but slower to the left.
Carn't quite get the hang of inverted ones yet.
Or a rolling circle (thats just about the holy grail of 3D glider aerobatics)
Dec 09, 2017, 08:24 PM
aka: Scott Ellis
Xeric's Avatar

Update!


My foam box has been modified. Note the handle on the top, now. Why do this, you ask? Is it so I can get the box down my narrow basement stairs more easily? Yes, but that's not it. Is it so I can hold the box with one hand while unlocking the truck? Yep, but that's not it, either? Give up? See the black stick at the core of the "handle" hole? You can't lift the box without that black stick. You can't load the box in the truck and drive seventy miles to a likely new spot and find there a fine breeze and go to assemble the glider and realize that YOU DON'T HAVE THE BLACK STICK!!!

The black stick is, of course, the wing joiner tube.

Good thing I also had the Alula along.
Dec 09, 2017, 08:44 PM
King of Crash
madwinger's Avatar
Quote:
Originally Posted by Xeric
My foam box has been modified. Note the handle on the top, now. Why do this, you ask? Is it so I can get the box down my narrow basement stairs more easily? Yes, but that's not it. Is it so I can hold the box with one hand while unlocking the truck? Yep, but that's not it, either? Give up? See the black stick at the core of the "handle" hole? You can't lift the box without that black stick. You can't load the box in the truck and drive seventy miles to a likely new spot and find there a fine breeze and go to assemble the glider and realize that YOU DON'T HAVE THE BLACK STICK!!!

The black stick is, of course, the wing joiner tube.

Good thing I also had the Alula along.
Good laugh I just had reading that. 😂

Thanks.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product Sneak Peek at the NEW Revolectrix BUMP Controller Tim Marks FMA Direct 1428 Nov 18, 2017 03:33 PM
New Product Voyager 4 Zoom Sneak Peek Walkera Quadcopter Review Walkeralive Multirotor Drone Talk 1 Jan 11, 2017 02:12 PM
New Product Mobius Mini Sneak Peek Tom Frank Aerial Photography 150 Aug 24, 2016 12:00 AM