On 15th June RCTLG dived into the ground at full speed from about 20ft during histart launch. The others said the towline wound itself around the wing. Hard to believe. Maybe the line was tangled in the wing before release. Most probably the line must have hung up on a bush, making the line pull the model down.

RCTLG appeared to EXPLODE. It was shocking.

However the damage was surprisingly little. Underfin came off. One side tailplane came off. Servos uprooted but undamaged. Wing retaining bolt (plastic) snapped. Ply bulkhead at leading edge position broke in half. Not even a scratch on the wing. Fibreglass skin really works. The wing does not even have any dihedral brace!

Lack of serious damage to fuselage attributable to:
1. Carbon fibre tube goes all the way to the front
2. Pod is glass skinned
3. Nose block is of ordinary thermocole with glass skin. This compressed absorbing the shock.

RCTLG since repaired and flown yesterday (in over 25kmph wind!)

welcome back sir

waiting for next aircraft  build

Good Show 

Launcher needs to launch, not just open fingers!
How do you like the zoooom at the top?
Missed capturing the landing on video.

https://m.youtube.com/watch?feature=youtube_gdata_player&v=II75F6T8wDo

www.youtube.com/watch?feature=youtube_gdata_player&v=II75F6T8wDo

Beautiful Iyer sir, that bird is just standing in air

45' of 3/16 surgical ( 20 pieces knotted together)
Height achieved presumably 200'
Best duration so far 90sec in 20km wind
Haven't been able to do 2min yet
Probable moral is that the AG03 airfoil can handle high winds,
but isn't the best of floaters at 5oz/sqft loading
http://m.youtube.com/watch?v=ulHKF3SsLHg&feature=youtube_gdata_player
www.youtube.com/watch?v=ulHKF3SsLHg&feature=youtube_gdata_player

 Great 

Admin (and all members)
In 70 days, less than 50 responses, but more than 6000 views.
Ie, over 80 views every day!
Hard to believe that that 5-6000 people saw the thread.
Is this for real, or is something like the Google Spider that is increasing the count?

Sirjee, that is because we love to come back and visit this thread to admire at your exploits, rather than put useless comments.. atleast this is my take. Maybe this is the case with others too! 

Eight months after reply #55 (1min 40 sec flight),
Indore RCTLG flew again.
For some reason, needed extra 13gms nose weight.
And managed only 1 min.
Looks like the rubber is getting old...

www.youtube.com/watch?v=IPW8qQQ9KNs&feature=youtu.be

   

You are tempting me to go home and hunt for bits of my glider built in Hyd (if you remember). Surely after all these years of transfers the glider would need big repairs!!!

A mos excellent build 

That's Really Good Sir.
Regards,
Aman.

Iyer sir , still 1 min is very good time.

Thank you manoj, aman, Rai saheb and Ashok.
This Sunday i plan to try out Hobbyking rubber.
I fear it may be too much, as it can take models upto 3kg - mine is only 200gms.
And the rubber is only 10m.
$3.69 cost me Rs 850 due to shipping!

Frank Zaic first mentioned HiStart in 1938!
In a 1944 article, he said something that i think is of utmost importance to anyone trying a HiStart.
He said 'Use the minimum power required'

Having successfully crossed that stage (using 7 times the glider weight as against the recommended 4-5 times), i'm wondering what will happen with a shorter length of stronger rubber. I would have preferred a longer length of weaker rubber.

Response of anyone with first hand experience requested.

Iyer sir, you are going to love this 

The rubber acts as a spring

Springs are chartacterised in their behaviour by the linear equation F=kx, where F is force, k is the spring co-efficient (a constant for a given spring) and x is the displacement

The first integral of Force yields Work or equivalent energy imparted

E = 1/2 k x²

Your interest is the amount of energy put in to the launch. Thus displacement (squared) is the defining factor.

So, a longer length, even of lower stiffness, will impart more energy to the plane (and have a smoother take-off incidentally)

Quote from: sanjayrai55 on March 19, 2015, 06:47:30 AM
So, a longer length, even of lower stiffness, will impart more energy to the plane (and have a smoother take-off incidentally)

Thanks. Must have realised this instinctively!
"I would have preferred a longer length of weaker rubber."
Unfortunately the new rubber (10m, 6/4mm od/id) is shorter and stronger than the existing one that is getting tired (15m, 5/3mm od/id)

Iyer sir, try and see if you can get surgical rubber tubing; as used in BP Cuffs, tourniquets etc.

Iyer sir if you do get a hold of surgical tubing source do share with me also, i am also on the hunt.

Sanjay sir i heard that surgical tubing gets cracked when used in sunny days. What other alternative for surgical tubing? is butyl rubber tubing that is in cycle tubing ok, though a long tube of small dia will be hard to find

Also sir if i find tubing suitable for hi start will tell you. Had gone to bafna surgicals thinking they might have some but they are only distributors of medical devices

Currently using 15x1m pieces of the yellow surgical tubing.
Will try red HK tubing 10m tomorrow.

Nose weight needed last Sunday was stone(white)+plasticine(blue) 13gms.
The keychain camera weighs 14 gms.

Wondering which to use as nose weight tomorrow...

Found that the Hobbyking rubber 6mm x 10m was not suitable for this 200gm glider.
Low pull gave less height.
More pull gave gave a loop.
Leading to a hit on HT lines.
The CF tube led to a short circuit.
That set the tail on fire.
Fin burnt away before rescue.
Towhook vanished in the spark.
Fibreglassed wing shows only a small dent.
Hope Rx and servos are not fried.
Though the video from the onboard camera has vanished...

Sorry to hear of this Iyer sir

The spring constant " k " was indeed too high. Too much force at start. 

Go back to surgical I think.

Quote from: RCNeil21 on March 19, 2015, 01:18:31 PM


Sanjay sir i heard that surgical tubing gets cracked when used in sunny days. What other alternative for surgical tubing? is butyl rubber tubing that is in cycle tubing ok, though a long tube of small dia will be hard to find

Neil, a little Glycerin rubbed into the rubber keeps it soft and pliant, no cracking

Similarly, store rubber bands in Talcum Powder to prevent them getting sticky  

Hope the MP grid survived the hit Iyer sir.