Build Log : Carl Goldberg Tiger 2 Low Wing Trainer for 5th Sweepstakes

Started by Mjet, March 18, 2014, 01:14:12 PM

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girishsarwal

Oh I missed this thread somehow... great work Mohan, look forward to the maiden... all the best
gs

Mjet


allthatido

Super Mohan Ji..ap to bahut aage nikal gaye. Good to see that :)

K K Iyer

Wing looks nice and strong without being heavy.
Before covering you could give it a light rub down with fine sandpaper mounted on a sponge, so that you get a mirror smooth finish on the covering. What will you use? Monokote?
Best wishes.

Mjet

Thanks Ankur Bhai - This is my First Balsa Build and your initial guidence to motivate me in this hobby.

Thanks Iyer Sir for kind words - I did some light sanding on wings  ( 400 Grit ) , still it require sanding , pl suggest ? I am using covering from Lotus Hobby ( white and Green ).

Pics of Complete Fuse with Wing. Some small adjustments need to be completed before covering. Pl suggest, If can drill my fuse to reduce significant weight without affecting the strength.

Left TIP is inclined down very minutely; does it affect the flying characteristics?

sanjayrai55

Before drilling the fuse try a mock assembly to see where the CG will fall.

Mjet

Sanjay Sir - CG is comming as per plan. 3/4 inch from leading edge.

sanjayrai55

Then don't do anything!

3/4"from the LE seems odd BTW. Should be around the spar I would have thought

iwincar


Mjet

I already checked assy with all parts (with out spinner), so will mind your thought at the time of final assy.

thanks " Iwincar".

K K Iyer

@mjet
1. As Rai saheb says, CG at 3/4" from LE is wrong. Pl recheck manual (available on internet)
tiger2 manual says CG should be between three and a half inches to four and three eighth inches back from LE

2. Even a slight twist in the wing is equal giving a lot of aileron control. If not corrected, will make the model roll to one side on takeoff. Temporarily stick a 1/8 square strip of balsa about 20" long to each wingtip, and see if they are parallel. If not, you will have to steam the twisted wing in steam from a pressure cooker, twist to correct and hold till cool. It will work only for small twist, as these 'D tube' wings are quite rigid.

3. Feel the surface with a finger for imperfections, especially at joints. Sand with the sandpaper attached to a sponge. After steaming (and cooling) final light sanding will be needed, as some fibres will become visible.

BE VERY CAREFUL AS STEAM ON YOUR HANDS CAN BURN THEM BADLY!
Regards.

Mjet

Sir, actually wing is ok.but right wing tip is minutely up side.I will post pics.

K K Iyer

@mjet
Your description is not clear.
'Right wingtip is up side' what does this mean?
At the leading edge or trailing edge?
Please verify that the angle of attack is the same at both wingtips, as suggested earlier.

You didn't say anything about the CG  ???

Mjet

Sir, please see the photographs and suggest for wing Tip.
One month back I checked the CG with all parts and now I am Confused, so can't tell you about the CG measured at that time , was it ¾ or 3 -3/4 ? You are correct, that CG should be 3-3/4   Apx or Near to Spar, as Sanjay Saheb said.


K K Iyer

If it is slightly bent like dihedral, no problem.
But if it is bent up at the LE, and bent down at the TE, it will be like an aileron. If so, then better to cut off and rebuild the tip. Or have a model with a permanent tendency to roll.

sanjayrai55

That wing tip is fine. Don't worry.

CG - if you checked it (and you are an experienced builder) and moved forward, obviously it must have been at 3 3/4", or you would have actioned corrective procedures

Mjet

Ok sir, I will take care and update you and take guidence on CG. Now starting covering.i was worried about wing tip, so covering was on hold.

sanjayrai55


Mjet

All Done, Almost there for the maiden if weather permits..

Mjet


Mjet


Mjet


ashok baijal


sundaram


girishsarwal

Fantastic build Mohan. What do you plan the power system as? Glow or Electric?
gs