otterdriver

Hi Guys Is there anything out there that snaps as quick and crisp as a composite ARF in the 33-40% size in IMAC style flying. Mark,

Flyfalcons

Not that I have seen, many people at contests have commented on how well my comp-arf snaps and how sharp the leading edge of the wing is.

Shortman

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Sure, get any giant scale plane, add 10lbs of weight and make the wingloading high, fly at a stall speed and pull into 3d rates with your elevator, it snaps very quick, though its hard to determine which wing drops first lol. Works great with my Hangar 9 Edge

rmh

Rapid snaps are not a function of the LE design- -tho it can influence

It has to do with how easily the model reaches critical AOA
My extremely light electrics will do 2 snaps in under a second- under 5 oz /sq ft
On Dalotels - with wing loadings of under 22oz /sq ft- and nice smooth LE setups -the snap rate is almost as fast .
The best 40% stuff we have done . are also very light -and snap with a vengance.
again , gentle LE design.

ptgarcia

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I'd put my wife up against any plane out there...

otterdriver

Hi dick What would be your opinion for the best airfoil % for a UNLIMITED class IMAC plane there are so many snaps at every angle imaginable the plane needs to be able to stop on a dime without over rotating. I know it is all about timing but it seems it would be easier with a plane that stops the snaps quick. The only one I have flown that is that quick is the compsite ARF but the durability issue on flying off of some rough fields worries me. Mark,

otterdriver

How about the giles I have never flown one but they seemed to be very popular for a while but you don't see many anymore. Is it because the way they flew are because we are in the XTRA fad right now. Mark

3DFanatic

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It sure helps if it's a CAP 21 that you add all that weight to...

MarkNovack

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Mark,
Reference the Giles, the local opinion as to why it faded away reasons that the full scale airplane, after construction rights were purchased by Mudry, was the decertification of the airframe, halting the production of the nest generation Giles. There was, according to sources, a problem in the wing design. The scarcity of the full size design definately impacted on the modeling world. As Mudy is still selling CAP232s, Walter Extra is still selling Extras, Zivko is still knocking out Edges, and Sukhoi and Yakolov are going strong in their production these airplanes remain prlific in the modeling world.

Mark

rmh

best airfoil?
No such thing-
Good airfoil for low wing loading tho ----is a 12%root -10% tip - about 35% highpoint
All of this is for a monoplane and the compromise is for strength (12-10%)
This design can be built very lightly and still be strong- It is close to what some composite kits use.
I use 1/16" thk balsa on 1 lb foam with some minimal top/bottom spar extensions ver the wing joiner tube.
On a well designed bipe - 10%constant is good -even thinner if you can stand to rig the thing.
Fat airfoils are more forgiving and stronger typically -and heavier -cept on th little "3D thingys".
the but is that they are sometimes hard to tilt quickly to stall angles required.
My Giles and Dalotels snap instantly and recover just as fast -
I also use a CG forward of where the "3D " setups go.

ilikeplanes

Interesting thread. I'm having trouble with snaps on my Patrick Extra. Critical AOA certainly seems to be the trouble. It's a new airplane for me and I'm still getting used to it. It seems to be very resistant to stall even at slow speeds and high AOA.

It makes me wonder about airplane design intent. If an airplane is intended primarily for 3D, will it necessarily be very stall resistant and stable at high AOA? Does such an airplane suffer when doing conventional aerobatics like snaps and spins? What design attributes makes an airplane stall resistant and stable at high AOA? Can you take stall resistance too far?

Just wondering.

otterdriver

Mark. your probably right about the Giles.but I sure would like to fly one.
Dick I sure would like to try that wing setup on a couple ARFs H-9 330s and WH 330 is there anybody around that will cut the wings to customers specs.I got to see Hanno fly one of the Dalotels back in the day he sure made it look like it flew great and with perfect snaps. Mark

kevinf2501

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My H9 33% Suhkoi does great snaps!

jongurley

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I was looking for a 40%er, but does anyone have any comments on the Composite-arfs" durability, I like the arf aspect of it but I don't want it to start cracking, and splitting in a year...

airega1

My Feedback: (204)

This my GSP 35% Giles 202 (in my avatar) it flies beautifully and snaps very rapidly, it's powered with a BME 102 (pre evo) and it runs like a Rolex. It's actually my son's airplane in which he's learned to do incredibly slooooow rolls! He practiced on his G2 and picked it up quickly on the real plane.

rmh

Best Snapper ?
The current rage for planes that simply hover, has created of a problem for ARF mfgs.
The eager buyer, equates a hover type with a great aerobatic setup
Typically, this is NOT the case.
If the flyer is really new at this - , he will tend to easily stall and snap most good aerobatic setups .
So-- the hot HOVER setup becomes a very fat airfoil- less critical of pitch
Fat foils do NOT make more lift -they just harder to stall .
That is why so many articles describe fat airfoils as high lift types. -which is NOT true.
So--combine a very fat foil-say 25% thick, with a very low wing loading and you have a very forgiving setup-
Once the power is sufficient to hold the plane in a vertical attitude, the wing airfoil is unimportant --BUT going thru the "flying on the wing -to flying with the prop" phase, can and does present a stalled wing .
The more this wing remains insensitive to Angle of Attack, --such as a very short span / thick airfoil, the easier it is to control .
Now --let's try to make a good aerobatic setup with an thinner airfoil which snaps readily on command, yet is still easy to fly.
The easiest fix -design wise --is simply to lower the wing loading.
Most ARFS however end up with high wing loading--(for scale areobatic models.)
Why?
The newcomer wants a great looking scale type hovering , full aerobatic model.
The reality is that the newcomer really needs a model which can survive a nasty landing and a few tumbles.
So the manufacturer tries to compromise .
If the result is not attractive or sturdy enough for the new guy,- he looses his prime market.
There are a few, very good, very light scale type arobatic types on the market .
These can easily be broken and repair is almost impossible for a newcomer.
BUT--if you are after good results , these do fly the best.
Another BIG problem is trying to setup a model for both good aerobatics and 3D flying-
Some manufaturers recommend huge control throws -which totally wreck control resolution on std servos
plus aft CG locations which compound the issue of good controllability.
The newcomer is supposed to figure out how to switch rates as needed.
So how do the heros and experts do all of it with one airplane?
Easy- they first learned how to fly aerobatics- and many also learned helicopter flying.
Combine the two and you have a background in skills needed to do 3D very well.

jongurley

My Feedback: (29)

[sm=sleeping.gif]

rmh

I guess I put some to sleep----

otterdriver

Hey Dick I think you hit the nail on the head. My question exactly is there a ARF that they havn't compromised on and is setup more for sequence flying and more for a skilled pilot.Or is there a company that can make wings and tailplanes to convert one to such a aircraft. Mark,

jongurley

My Feedback: (29)

No Dick, I am just messing around at work, your explanation was excellent, I was just concerned about the durability of a composite..

rmh

Durability and composite are mutually exclusive.
Why?
the lighter and more rigid the "composite",
the more resonant it becomes.
Eventually, fatigue sets in.
I saw a new composite which uses balsa sandwich for fuselage layup- this may be better - but have not seen how well it stands up under constant buzzing from the engine.
I use a lot of sandwich balsa -which is very durable.
Also - not very resonant -