Doc I missed this question of yours


Read my Post on Trim Drag & forces in a flight posts

http://www.rcindia.org/rc-general-topics/basic-aerodynamics-for-rc-flying/msg82364/#msg82364

http://www.rcindia.org/rc-general-topics/basic-aerodynamics-for-rc-flying/msg82364/#msg82364

Excerpt of post on Trim Drag is as follows



When it comes to Canard, for balancing forces in flight, instead of tail down (Which adds to the weight component and therby adding drag) canar provides a nose up force and thereby reducing the force on wing and reducing drag. if canard was such a great thing and has only advantages why didn't it find favour with conventionally designed aeroplanes ? that is the pertinant question to ask (Remember wright brothers envisaged canard controls and not tail mounted controls, first aeroplane was in fact a canard controlled aeroplane)

Anyone can shoot the answer (Without googling ofcourse) we will proceed with the discussion of advantages and disadvantages of canard controlled flights and why didnt it find favour post 'Flier')

Well

the simple answer is, if a tailplane stalls the aeroplane will pitch down and unstall(Both the wings and the tailplane will unstall) which is desirable, whereas if the canard stalls the aeroplane will pitchup and thereby worsening the situation

One Question... What are wing pods used for?

could you post a pic of which pod you are referring to

the pods in commercial aiplanes like b737 a320 etc

https://www.google.co.in/search?q=wing+pods+airbus+a320&oq=win&aqs=chrome.1.69i57j69i59.2875j0j7&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8

something like this

the second pic
in the pics displayed

Well

Pods are payloads that aeroplanes carry, they can be Podded Engines (like the pic above), Flap Guide rails encased in a pod looking aerodynamic sleek structure, Drop Tanks (External Fuel Tanks, which after empty can be dropped), Photo Reconnaissance Pods, External Guided and Unguided Bombs, Missiles (Some looks like a pod)  etc

If you google the words above, and closely see the difference you will know what i mean

Hey rcpilotacro  I have made my new great planes piper cub with OS 62 V four stroke engine and for extended flights i have put du-bro fuel tank which 950 cc. so can it fly well with this kind of fuel tank , i mean will it be able to fly ?

Please HELP
ASAP

Thanks

My piper cub is of 76 inches wing span

Please  help me in how can i manage to fly with this fuel tank as i want to fly with this fuel tank

I read ur pm and replied. Answer is no

does a polyhedral wing require washout....if yes then how will u induce washout into a wing structure

@abhishekdas11
Washout has no connection with whether the wing is straight, dihedral or polyhedral.
Washout, ie tips at a slight (say 1 degree) negative incidence compared to the root, is to reduce wing dropping tendency by delaying tip stalling.

Traditional methods for inducing washout (that you may laugh at):
1. Lick the underside of the trailing edge near the tip, or blow hot breath, twist and hold. For balsa chuck gliders.
2. For stick, tissue, dope models steam the tip using a kettle/cooker, then pin to building board with shim under tip TE. Or apply a coat of thin dope and pin with shim till dry.

For foam core wings, set tip template at a slight negative incidence to root template before cutting with hot wire.

BTW, curious why you felt the need for washout!
Regards

just wanted to ask whether its required for sailplanes and gliders with larger wing span....like a mandated kind of...

The answer is 'Yes'

Gosh hw will i do it in balsa...........is there any other method other than licking and blowing breath onto balsa wood... i mean like tapering the spars chordwise or likewise strctural

@abhishekdas11

Just put a shim under the TE at the tip while building!
As the spars are spanwise, doubt if you could taper them chordwise, especially if there is only one spar

If span is over 6ft, other alternatives like different sections for root and tip etc...

An 18-24" semi span wing in 8mm biofoam with no aerofoil at all will still fly quite well if the wing loading is not too high. Even without any washout!

Washout is just one of the design considerations, important but certainly not the most important.
Before washout are issues like:

- what is the wing span
- what is the chord at root/tip
- what is the wing loading
- what aerofoil section is proposed
- at what Re number range do you expect the model to fly

Abhishek, i must ask if you are diving into the deep end unneccesarily?
You can build/fly a model successfully without any of this mumbo jumbo.
Do you want to be a reasonably successful model flyer or a model airplane designer?
There is a difference between the two.

I am at your service either way. But you have to decide.
Luck!

well to b pretty frank....i am a successful structure Er... jus wana put som stuff like wash out, winglet and vortex gen onto ma SO CALLED GLIDER :-D to giv it a pro look...
wing span 66"
root chord 5"
tip chord 3"
wing loading 5.83
no idea abt reynold number

airfoil is clark Y airfoil of 70% thickness

See what you just said!

y anything wrong?

@ KK Iyer- i made a wing without ailerons to b controled ba rudder...so wt i thought ws if i incorporate a washout then my banks will be smooth and even else the airplane will just yaw and sideslip

Despite efforts unable to understand language used.
Unable to advise as no experience with 70% thick airfoils, ie, 3.5" thick at 5" root chord and 2.1"thick at 3" tip chord.