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Old Apr 08, 2008, 03:06 AM
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Ljubljana Brnik, Slovenia
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Build Log
GUPPY electric sailplane Building&flying PART 2

Hi all!

As Guppy thread grown to unexpected size, with record breaking number of visits, (quarter of million visits in less that 2 years) I decided to start PART 2 of that story.

Link to PART 1: http://www.rcgroups.com/forums/showthread.php?t=539755

So, here we should continue with PART 2:


Mitja
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Old Apr 08, 2008, 03:43 AM
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Quote:
Originally Posted by kr3cik
Finaly, after two crashes, my guppy flys:P
It is nice to see another Guppy in the air!

I wish you many nice flights!

Mitja
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Old Apr 08, 2008, 04:25 AM
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FIRST!!! yuupiiiieeeeee!!!!

, I was first...

Congrats Mitja for this wonderful flying fish...

Layer.
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Old Apr 08, 2008, 04:36 PM
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It looks like I was the last who shown his model in first part
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Old Apr 08, 2008, 08:47 PM
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I have been building mine for over a year, wow but I have built a few planes in the interim. She is coming out real good though.
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Old Apr 09, 2008, 12:19 AM
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Canberra, Australia
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Ailerons & elevator, no rudder?

Is it necessary to have a rudder on a Guppy (with Hotliner wings)?

Although I'm new to sailplanes, I've been flying electric sports planes for years. Many of my planes are aileron and elevator only, with no rudder. Only my 3D plane has a rudder, and I mostly use the rudder during aerobatics, rarely otherwise. I'm not expecting to do a lot of aerobatics with the Guppy.

Thanks for any help. And Mitja, thanks for such a beautiful looking plane.
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Old Apr 09, 2008, 02:28 AM
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Quote:
Originally Posted by digital21c
Is it necessary to have a rudder on a Guppy (with Hotliner wings)?

Although I'm new to sailplanes, I've been flying electric sports planes for years. Many of my planes are aileron and elevator only, with no rudder. Only my 3D plane has a rudder, and I mostly use the rudder during aerobatics, rarely otherwise. I'm not expecting to do a lot of aerobatics with the Guppy.

Thanks for any help. And Mitja, thanks for such a beautiful looking plane.
Using rudder on aileron Guppy is not necessary, but you can fly more coordinated turns and loose less height, so thermalling will be more efficient using rudder.

But if you would like to fly mainly fast without hunting thermalls, then you can forget the rudder.


But regardless of all, I recomend use of the rudder. It will improve your flying skills.

I often find myself, that I spontaneously move rudder command on the transmitter even when model has no rudder installed at all (my latest flying wing in Delta configuration)

Mitja
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Old Apr 09, 2008, 06:20 AM
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Any 1m Guppies? Mini Guppies?

Mitja, Thanks for such a quick and informative reply.

I've seen some posts about making larger versions of the Guppy, but has there been any feedback from people making smaller versions with a wingspan of 1 metre or so?

Thanks!
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Old Apr 13, 2008, 12:35 PM
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I am making progress on cutting the parts. Yes by hand.. The fellow that cut all the parts in one evening must have been up all night..ha ha. It is a process ...Found that the best way to do this is gluing the templates on the balsa with rubber cement...secures the template to the balsa and easy to rub off later (no added weight from a tacky spray)...I also found that a table jig saw made much smoother cuts........If OK with the site I will continue to provide info for new builders like myself on suggestions as I am sure some of you more experienced builders already know these tricks but some of us newbies do not...

I am 90% done on cutting the parts so getting excited about the construction part!

Found the carbon tube at Fleet Farm (an arrow shaft)...Wal-Mart does carry arrows until the season opens around here...perfect tube I would say about 3/8 but fits the plan perfectly...Ouch $8

A few questions before I start that I want to make sure that I get it right the first time

QUESTIONS: The screws that go through the wing appear to go through the wing spars? That would certainly weaken that area? or crack the spars? Or am I missing something?

Directions for Rudder construction say "Glue the parts on the bottom sheeting...Then sand to a taper prior to the covering the other side? This is sanding only one side of the internal construction and would this not put a different angle on one side and not the other...I could understand sanding the internal pieces with taper on both sides prior to gluing to the bottom sheet? What is the correct way to do this?

Hinges for the Rudder and Stabilizer is just like cellophane tape (scotch tape?) Is this strong enough? How then do you cover over the tape with the covering film on the hinged edges that meet?

Motor mount says from 4 - 6 degrees...Is this just best guess? Or is there a more exact or technical way to do this?

I am having a great time building this beauty! Will keep all posted and some pics along the way...............Lee
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Old Apr 13, 2008, 03:30 PM
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Thanks for sharing the plan of this beautiful glider

Dear Matja,

First, thanks for sharing the plan of this beautiful glider. It's really a good job! If you have some plans of other gliders or planes, do not hesitate to share them!

I have started the construction of a Guppy last week. Now, the glider is ready to cover. I will probably make the first flight this week-end. Here are some pictures.

I will also start the construction of a hotliner wing and also a fuse without motor.

The construction of the glider is very easy with your instructions manual and the huge quantity of informations in this thread. Thanks to all contributors.

For the motorization, I'm using an e-flite Park 400 with a Lipo 3S 1450 mAh.

more details on my website

Geoffroy.
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Old Apr 18, 2008, 12:13 PM
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Sheboygan, Wisconsin USA
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Help Please regarding questions in post #9

Hi:

I need a little help (please) I asked a few questions in post #9 and was hoping for some guidance? Thanks Lee
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Old Apr 19, 2008, 09:26 AM
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Lee3429
1. Yes the screws are going through the wing spars. You can reinforce that area with strip of glass fabric http://www.rcgroups.com/forums/showt...539755&page=32
3. Yuu must first cover rudder and stabilizer and then make the hings
4. parts are cut with that angel (I think..)
With no. 2 you must follow the instruction my englisch is not strong enought to explain that.
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Old Apr 19, 2008, 01:52 PM
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I was thinking about this motor QRP-HYP400-N
can you suggest me a folding propeler and a lipo battery for this unit?
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Old Apr 21, 2008, 02:42 AM
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Ljubljana Brnik, Slovenia
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Quote:
Originally Posted by Lee3429
The screws that go through the wing appear to go through the wing spars? That would certainly weaken that area? or crack the spars? Or am I missing something?
Wing bolts goes trough the thick root wing ribs, not trough spars. You should drill those holes precisely and reinforce them simply soaking the balsa with CA glue.
Quote:
Originally Posted by Lee3429
Directions for Rudder construction say "Glue the parts on the bottom sheeting...Then sand to a taper prior to the covering the other side? This is sanding only one side of the internal construction and would this not put a different angle on one side and not the other...I could understand sanding the internal pieces with taper on both sides prior to gluing to the bottom sheet? What is the correct way to do this?
I did as I described in the instructions and correct the possible warp when aplied the other side balsa sheeting. The rudder is straight.
Quote:
Originally Posted by Lee3429
Hinges for the Rudder and Stabilizer is just like cellophane tape (scotch tape?) Is this strong enough? How then do you cover over the tape with the covering film on the hinged edges that meet?
You should cover the tail feathers separately. When covered, you use clear self adhesive tape (1 cm or ~3/8" width) and join moving part of tail to the stabilizer. (rudder to fin, elevator to stabilizator). You should use tape on both sides, but allowing free movements. The clear tape is strong enough, but you can use also a hinge tape available in hobby shops.
There is also another solution, just to cover both part with one piece of covering and use that covering as a hinge. But you must know what you are doing as covering shrink under iron and is kind of tricky business to achieve proper hinge function.
Quote:
Originally Posted by Lee3429
Motor mount says from 4 - 6 degrees...Is this just best guess? Or is there a more exact or technical way to do this?
The ammount od side and downthrust depends strongly of the motor torque and propeller. The stronger the motor, more side and downthrust is needed.
With such mounting of the motor, we prevent that model will want to do a loop under full power and go circling. There is a side effect also on the outlook of the model. More side and downthrust of motor, more odd became the nose of model
But anyway pilot should compensate any unwilling tendency of model under power using proper ammount of correction on controll sticks (elevator and rudder), or if transmitter allows, you should set some mixers (K1->ELEV, K1->AILE) to fight those unwilling power side effect.

Mitja
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Old Apr 21, 2008, 03:16 AM
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Quote:
Originally Posted by orck
I was thinking about this motor QRP-HYP400-N
can you suggest me a folding propeler and a lipo battery for this unit?
Motor looks good for use in Guppy.

Folding propeller (Garupner, Robbe, Aero naut.) 6x3" (15/7cm), direct drive (No use of gearbox!)

2 cell Li Po battery (7,4V) from 800 to 1200 mAh (2S1P)
DONT use 3 cels Li-Po (11,1V) as will burn your motor in short period....

Note: your ESC should support 2 Li-Po cells in order to disconnect motor, when battery voltage drop under alowable value. Li-Po cells are more delicate than NiMh cells!!!

You should allow for cooling air to flow trough motor, specially over the brushes, and exit from model. Motor will run hot if you force it contunuously over a minute. But in one minute you will anyway reach decent altitude to stop engine and start to chase thermalls.

Look at your local Hobby shop or at some Internet stores for the equipment.

Mitja
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