Building the Guppy Glider

[msc]

With the mistakes learned in the failed attempt, I got the 1.5L H20 bottle and tried again. Bearing in mind the following:

1. The canopy is formed when the bottle is shrinked, the result would be a smaller bottle - consideration: Go for a bigger bottle
2. When heated, the shrinking of the bottle will take up the shape or any space inside the bottle - consideration: Squeeze foam plug as tightly into the bottle as possible. All air gaps should be filled with scrap foam
3. Your significant other half will feel neglected when you spend too much time building planes - consideration: space out the build time, clean up after each build session, buy her a big present or two

As the foam plug was realtively easy to shape, I manage to finished this canopy from start to finish in about 1 hour total.
The empty air space inside the bottle, after putting in the foam plug, was filled with as much scrap foam as possible. The whole bottle was then immersed into boiling water for 1 minute.You will hear the shrink noise, kind of like a well-mannered fart, when you put the bottle into the water.
The result was very good! Success, at last!

The canopy edges were cut off with a kitchen scissors and the outline of was traced as per the canopy in the fuselage. The black trimmings were stick on with the leftovers of the decal from my Formosa.

Now, I can safely announce that I know how to make a canopy.

I am very close to maidening the Guppy glider, need to go hobby shop and buy a pair of new folding prop first.

MS

[Sunstorm]

Wow that's great! Phew! I gave you the right advice that H two O bottles work! Well, you drank one bottle of snake water, but it's ok, you can do with the cooling effect!

And great advice with the wife too! I shall practice on my gf. I try not to talk about planes when I'm with her...

Looking forward to see the glider fly!

Weather is great these days for thermal soaring.

[Heli_fanatic]

Weather is great these days for thermal soaring.

you bet man.....

[msc]

Yes, I need to wrap up this project soon. I can see signs of relieve from the wife when I clear up the mess on the floor.
I should be flying the glider this weekend or sooner. Cannot fly too high due to poor eyesight, could be age catching up with the rest of the body. Or I should re-phrase, the body catching up with age.

I'll change the context and use the joke that I read:

Ted who is 64 years old is doing many outdoor activities to keep himself active and took up RC Thermaling with his 2.5m thermal sail plane.
He came back home and told his wife that he'll most probably give up the hobby as he cannot see the plane from too high up.
"Bring your brother in-law, Sam, with you the next time. He'll need some outdoor activities, he's already 80, you know" said the wife.

The next day, Ted brought Sam to the flying field and flew his glider very high up. He encountered a thermal and it blew the glider very high up.
"Did you see my glider on the right?"
"Yes!, yes! I saw it" said Sam

"It turned right, where is it?" asked Ted

"I cannot remember"




Hope you like the joke.

MS

[msc]

The Guppy is ready for flight!

Got the Aero-Naut folding prop, fine adjustment with the 2 servos, mounted the motor and spinner, added velcro for the ESC, Rx and Battery.......the Guppy is ready for flight. Hopefully, the weather is suitable on SAT morning.

The nose of the fuselage leave very little space for the motor wires. I glued the wires on the bottom of the fuselage to prevent the rotating drum of the motor from rubbing the wires. With the small 2s battery, the power from the motor was not fantastic, but I think it will carry the glider up. I do not have a weighing scale, but I think the total weight of the glider is less than 500g.

Stay tune for the flight report!

MS

[joe yap]

Got the Aero-Naut folding prop, fine adjustment with the 2 servos, mounted the motor and spinner, added velcro for the ESC, Rx and Battery.......the Guppy is ready for flight. Hopefully, the weather is suitable on SAT morning.

The nose of the fuselage leave very little space for the motor wires. I glued the wires on the bottom of the fuselage to prevent the rotating drum of the motor from rubbing the wires. With the small 2s battery, the power from the motor was not fantastic, but I think it will carry the glider up. I do not have a weighing scale, but I think the total weight of the glider is less than 500g.

Stay tune for the flight report!

MS

Nice job and good luck for your maiden!

Just a suggestion. Gliders spent most of its time gliding without power, so your best bet in your electric setup should be as powerful as the motor can be and yet your battery does not need to have large capacity. Using a smaller Lipo with more cells and higher C-rating is the game, as long as you don't exceed the voltage and current draw for your battery,ESC and motor. The idea is to achieve very steep and power climb for just under 1 minute to get to thermal height. The rest of the time should be spent hunting for thermal until it gets too low before going for another climbout.

Also, sometime to save space, I cut the wires from ESC or motor to length and solder them directly to each other. You'll save 3 set of connectors and plenty of space.

[Vortices]

Good luck!

Pls do check stab and wing incidence before flight. I am sure it will fly well.

cheers
good luck again

kevin

[msc]

Thanks for the tips Joe. The 2s is very small, and the space within the fuselage is very generous. I will not have problems fitting a 3s into the space. I saw some videos of others flying the Guppy and I would think that this is a very gentle glider and should be easy to handle.

Kevin, the recommended incidence of the stab with respect to the flat bottom of the wing is negative 1 deg. I think I might have eyeball it right. Also, the motor is mounted about 2 deg down. There is also wash in at both the outer wing panels. I think I got all these details in order.

The only concern is the bottom of the fuselage, on landing impact with the ground. I think I'll tape the extra plastic shell from the botched-up canopy at the bottom to save it from scratches. Kind of like the "new car" attitude for now.....

Thanks for all the tips!

[msc]

Successful maiden of the Guppy!!

The maiden was conducted at the field early this morning. The condition was just right. Very light wind coming from the SE, the sky was not crowded, not too many people at the field.

Met Annan there and he helped to maiden launch for me. Prior to maiden launch, checked all controls, did a range check as I have not used this Rx for some time already. As I have already balanced the CG of the glider at home, I did not perform further CG checks.

Annan launched the glider into the wind, I was powering the motor slightly more than half throttle. When the glider was launched, it flew straight and level, I gave it full throttle and it begain on a gradual climb. The 2s battery was more than sufficient, but the climb was not fantastic.
When it reach gliding height, I shut down the motor. I had to trim 3 clicks of up elevator to let it fly comfortably. No trim required for the rudder.

As the glider was very light, it floated in the air, without power. The sink rate was very gradual. There was no thermal in the morning, but the steady wind helped to glide the plane along.
I found that the rudder had very good authority, it turned the glider very nicely. The Guppy looks good in the air, very beautiful and flies very gracefully as expected. Throughout the turns, I did not encounter any stall effects. There was also not any noticeable drastic drop in height when it was turning.

The landing was very smooth, as I was able to estimate the landing flight path and the sink rate. From the 2 flights of about 10-15mins each, I was able to land the glider a few feet in front of me.

After the first landing, the flight gitters was still tingering inside my body. This is a signal for me, on almost all first flights! On the second flight, I put a smaller battery on, and stick it closer to the nose. However, when I cut power, I noticed that the CG was a bit too far back. I will have to put it further forward the next time.

No modifications, no additional work to be done, for now.

I am a very happy man, seeing my scratch build in the air! I like the glider very much. The only issue about the one-piece 1.5m wing is that I was not able to put the wings into the boot of the car. Had to put it length-wise, between the driver and passenger seat.

Hopefully, there will be others who would build the Guppy. I guarranty those who build it will have 101% satisfaction.

More gliding days ahead.

MS

[randomtask]

Hey Kah Marn,

Congrats on the successful maiden. I have to say those curves on the fuse look sexy in real life. Really looks like a glass fuse at one glance.

Cheers,
Adnan

[joe yap]

Congratulations! 100% is satisfaction. 101% means addiction! Build more!

[MeePokMan]

Kah Marn - Congrats! The Guppy looks very happy in the sky.

[muah]

congrats bro...

a scratch build plane flying in its element is as rare as a meeting between a polar bear and a panda!! =)

[leonlio]

...

Well Done MAN!
Your build thread almost inspired me to start my on scratch... almost.

[msc]

Thanks for the encouragement guys. I may build the 2m version sometime in the future, baring many other domestic factors. For now, I'll take more time to enjoy some more flying.

Some of the guys have asked me about the making of the canopy. I guess I was not detailed enough in the previous post. I was not able to take pictures of the immersion of the cut bottle in the boiling water as I was a bit hands-full. My wife was already sleeping and was not able to take pictures while I was 'cooking'.

You'll just have to try it out and see the results. Nothing beats doing it yourself to find out the mistakes. Here's more help:
The foam used is ordinary foam, this would shrink a bit together with the bottle, but with some careful consideration of the final size of the canopy, I think it should be managable. I would estimate that the shrinkage of the foam is about 1-2% from the orginal volume.

When you insert the foam plug into the bottle, fill-up the rest of the empty space inside the bottle with as much shaped foam as possible. Filling the space means you'll get less slack in the final molded canopy.

I poke the end of the foam plug with a long metal fork for handling purpose and dip the whole bottle into boiling water. The whole bottle is under the water for about 1 minute.

After the bottle is shrunk, take it out and run it under tap water to cool down. Use the kitchen scissors to rough cut the bottle to release the foam. If you are careful, you may save the foam plug by not cutting into the useable foam. You can use the foam plug for a second canopy, in case you are not happy with the first.

If you need a canopy, just try it out. If you failed, look at the shrunk bottle to see how can you improve the method. You'll need help in drinking those H2O as I did....my mother-in-law drank the H20 also!

Good luck.

MS