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President bi fly 48" Wing

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trebor20/01/2018 15:55:19
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1886 forum posts
212 photos

img_2706.jpg

Has anyone got the recommended c of g and control throws for this plane ?

jeff2wings20/01/2018 21:39:02
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762 forum posts
1789 photos

s-l1600 (25).jpg

help any ??

trebor20/01/2018 21:59:37
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1886 forum posts
212 photos

Does that say balance point under the top wing ? Can't quite make it out.

jeff2wings20/01/2018 22:15:01
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762 forum posts
1789 photos

s-l1600 (25).jpg

there you go,have one that I'm re-building ,found this 'out there' on the web,if it works let me know !laugh

trebor20/01/2018 22:23:51
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1886 forum posts
212 photos

What's the chord length of that wing ?

jeff2wings21/01/2018 12:14:13
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762 forum posts
1789 photos

Buy scaling up the image to full size using a known dim ( forward strut ) CG is 4" from LE .What engine will you be using ??

Anthony Scott 221/01/2018 13:08:12
70 forum posts
12 photos

Mine goes "well" with an ASP 75, tho' the roll is slow.

trebor21/01/2018 16:50:21
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1886 forum posts
212 photos

It came with a sticky laser 70

trebor23/01/2018 16:20:53
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1886 forum posts
212 photos
Posted by Anthony Scott 2 on 21/01/2018 13:08:12:

Mine goes "well" with an ASP 75, tho' the roll is slow.

What's your C of G, at the moment mine with a 9" chord on the top wing balanced out at 5.5" behind the leading edge taken from the centre as its swept back. At the moment it weighs in at 7lb, it feels like it will sink like a stone when throttle is off. Still to test it. dont know

Denis Watkins23/01/2018 16:57:36
3559 forum posts
166 photos

You are not wrong Trebor, they do sink well with no power on

But at least the wings can be kept level in the steep decent

And are brilliant to fly with the thick wings allowing slow fly with some power on

I have both the 25 and the 40, and the slow roll is due to one set of ailerons on 2 wings

A 60 2 stroke powers the 48"

 

Edited By Denis Watkins on 23/01/2018 17:02:56

trebor23/01/2018 17:09:17
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1886 forum posts
212 photos

How's your CofG, I need to get as near as possible. I don't want to smash this one I quite like it. Do you have any differential on the movements ?

Nigel R23/01/2018 17:41:08
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2618 forum posts
427 photos

trebor

I have the small one.

The CofG is dead on 50% chord of top wing. Hope that helps.

I found an amount of aileron differential to be useful. I would guess around 75% movement on the downgoing. IIRC I have about 1/2" elevator either way, about 5/8" or so of UP aileron, and around 3/4" either way rudder. Obv yours will be more being 30% bigger.

There is acres of wing area. 7lb will be fine on the big one. My small one is 4 1/4lb and can be flown quite slowly.

Lastly, drag, you will soon discover there is an amount of it. Mine flies nicely with a 2/3 full power. As Denis understates, "a steep glide" is obtained with power off. Sometimes this is quite useful! Especially flying from a small club patch. I usually come in at about 1/3 power to keep it moving forwards and cut it only after clearing the threshold. Fairly standard biplane stuff I think.

Denis Watkins23/01/2018 18:02:12
3559 forum posts
166 photos
Posted by trebor on 23/01/2018 17:09:17:

How's your CofG, I need to get as near as possible. I don't want to smash this one I quite like it. Do you have any differential on the movements ?

This model is very stable Trebor, you will not smash it

Tank and motor are ideally placed, so good plug, run in motor, clean fuel and no thought of a smash

5.25" from the leading edge on the top wing centre C of G

Differential is mechanical

Large disc on servo, with both ball joints next to each other, on the outer disc holes

There is barely any down on either aileron, yet normal up on each

Similar to the Precedent Harvard/AT6

The rudder is very effective and assists scale turns

And sideslipping a Bifly is a joy to watch

trebor23/01/2018 18:53:57
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1886 forum posts
212 photos

Dennis, has the Model 40 got a 48" wing ? When you say normal up, can you give me any rough up and down measurements.

Edited By trebor on 23/01/2018 18:54:28

Denis Watkins23/01/2018 19:24:45
3559 forum posts
166 photos
Posted by trebor on 23/01/2018 18:53:57:

Dennis, has the Model 40 got a 48" wing ? When you say normal up, can you give me any rough up and down measurements.

Edited By trebor on 23/01/2018 18:54:28

Yes, 48" wing, was classed as a .40 model

25mm up 5mm down, but I fly sedate, zero expo on any model, I strive to prevent the pilot being airsick.

I doubt that in flight that aileron gets anywhere near max, perhaps 20mm up

Get All the elevator you can for landing, with no expo again, approx 21mm up

And leave the rudder at max available deflection as rudder is always useful

This is not a pattern ship, but a beautiful looking kit build that maybe built heavy or light

The thick wings and small size make the airframe sluggish but a joy to fly

trebor23/01/2018 20:27:56
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1886 forum posts
212 photos

Thankyou yes I have only been flying a couple of years and the first plane I had didn't have a steerable tail wheel so the rudder was always left maximum movement to aid ground steering and I got used to it.

john stones 123/01/2018 23:46:27
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10273 forum posts
1475 photos

Bit unkind to call it sluggish maybe Denis, mine was a joy to fly....cue the sarky comments on my looks. lipsjs9.jpg

trebor24/01/2018 06:38:22
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1886 forum posts
212 photos

Have you still got the hair or has it shall I say disappeared smiley

Denis Watkins24/01/2018 07:39:07
3559 forum posts
166 photos
Posted by john stones 1 on 23/01/2018 23:46:27:

Bit unkind to call it sluggish maybe Denis, mine was a joy to fly....cue the sarky comments on my looks. lips

I was trying to be diplomatic John, for the young lads comment that this was slow in the roll

But as you say, they are a joy to fly, and solid, with knock off wings in the event of an ungainly arrival

These are great to build too

Nigel R24/01/2018 09:37:37
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2618 forum posts
427 photos

Are they foam wings on this size?

Fuse structure looks like Precedent's standard liteply type.

Surprised you need that much differential Denis. Is your smaller one set up in a similar way?

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