Gnome - 32" Glider Build Thread

[ujjwaana]

I  bought this 32 inch 'Gnome' glider kit plan for Rs 700 last year which has been gathering  dust lately. Before foraying into larger balsa plane like my upcoming Guppy, I thought this small plane would help me getting rust out of my Balsa skills. Lots has changed since mid 1990's you see.

This is a 32" Chuck/Tow line glider which I am planning to put Aileron/ Elevator and Electric power with a 16g motor. The plane kit was manufactured by Sarkar Models, Calcutta and retailed by MR Sampath of New India Hobby Center , Ulsoor Bangalore. Though the Balsa wood (or what ever) used is not of good quality, it is a good kit for some one to enter into Balsa plane building.

I would be covering the plane with  IronKote which I have ordered form HK , and would help me get on with Ironing the covering.

Below is the kit and the box. I have put together the Tail plane and would be posting the pic when I get back to home.

Anwar bhai, Why not put different Forum Section for Balsa planes separately ? I could not found a better section, as I anyway plan to make it electric powered.

[flyingboxcar]

Talk of IP rights? The plan is labelled Aurora and being sold by Sarkar models
Any way this was never meant to be a chuck glider but was a pure towline. Converted to RC it will please you. You would off course have to modify tail group, and I would suggest you go for rudder control instead of aileron.

[anwar]

Anwar bhai, Why not put different Forum Section for Balsa planes separately ? I could not found a better section, as I anyway plan to make it electric powered.

There are so many ways we can slice and dice this hobby   Balsa, foam, scatch, plan, kit, ARF, electric, glow, gas, turbine, free-flight, plane, heli, car, boat, etc etc.  If we were to look at permutations of these, it would get really out of control !  That is why I chose one scheme and decided to stop there, even though it seems less than ideal at times.

Judicious use of CONSISTENT topic titles within the currently available groupings should help eliminate the need for any more groupings

[ujjwaana]

Part 1 - Tail Assembly

I planned to pick up with the tail assembly as a starter. The reason being till now I had only sanded balsa to shape and never did Ribs-spar construction. Since most of tails are flat profile, even if I screw up the Semi-symmitrical ribbed tails of Gnome, thigs might be little forgiveing.

The Tail is composed of identical 8 ribs (all Balsa), with two ribs joined together at the center. There are two spars at de bottom apart from the leading and trailing edges.
I am planning to put an elevator at the tail and kept the tapered trailing edge for the purpose and planning to put a spar at the trailing end and attach the tapered piece to it.

Preperations:

1. Began with Sanding all the ribs stuck together so that all the pieces are of exatly same dimension.
All the ribs were held in position with the help of Quick Release Bar Clamp Tool, as I found it difficult to pin them with T-pins.

I used medium girt sandpaper to first bring them into shape and then used the fine one give them finish.


2. I then sanded the spar notches to same depth and width so that all the robs align straight on assembly. Always try to fit the spar while sanding to avoid over shooting.

3. Sand the leading and trailing edges.

[ujjwaana]

Assembling the tail

1. Laid the Plan on the drawing board(which can take drawing pin easily).

2. Placed a transparent cellophane sheet so as to save the plan from sticking to the tail assembly while gluing.

3. Placed the Leading edge and  the two bottom spars over the gide line and secured with pins. Note that I had to place some paper pacers below the spars because I sanded the notches in the ribs a bit deeper. There shouls be maximum contact between the wood.

4. Used a Spar alignment tool to stick the Ribs to the spars and the leading edge.
I used thin CA (would have used thick one, but mine one dried up in the bottle itself) to secure the ribs in place. The best way is to first place the rib in position and put a singe drop of CA at any one contact pint on each spar/leading edge.
I used Balsa Cement on all the ribs join point to give strength. I bought it from Mr Sampath and it didn't dry a bit even after a year of storage, equivalent :QuickFix. Balsa cement is a medium cure and get bit soaked up by Balsa and gives good strength.


I am waiting for CA/AC hinges to arrive in Vinay's order  before I can finish the elevator assembly .

Bear my other useless post till then

[R C]

Hey Ujjwal,

You have do a very neat job,    doesn't look like you are working on balsa after long time.
Are you planning to finish this by this weekend?

[tg]

The poor quality of these kits is amazing. The trailing edge side of the ribs wont match the height of the inner side of the trailing edge panel. You will need to position the ribs against the trailing edge panel and mark out where the ribs touch and then file/cut narrow notches on the inner side of the trailing edge. Also the ribs on both wing and horizontal stab must be filed down so that they taper down and align with the trailing edge panel. Or will need to make the trailing edge thicker on the inner side so that it matches with the ends of the ribs.

[sharlock]

The poor quality of these kits is amazing.

Means made in INDIA

[ujjwaana]

got some time to try my hands on putting shrink wrap covering (Aka - Monokote-Oracover) over Balsa. Gnome was my obvious choice.

Put the last spar on the trailing edge on the half finish Tail. Cut a 1" wide strip of 3mm Balsa and sanded to form the Elevators.

Covering the Heat Shrink on this solid balsa was much simpler. I first removed the protective layer from Hobby King covering film using scotch tape. Touched the Sealing Iron at one end and Stretched the covering a bit and touched the diagonal corner with the iron. Ironed the remaining portion and repeated this on the other side. Result - amazing.

Covering the Rib section of the Tail was a disaster. Since the tail assembly was so fragile, I could not clam it. Ironing over the thin rib did not give much strength to stretched the covering before sealing the other end. So the rest of covering was very Slack. I also forgot to trim the extra film on the leading end. So when  completed the wrap around, I sealed the other end over a clunk of covering of the first end.
 
<Thanks to Capt Manish - FlyingBoxCar for suggesting to use a discarded cotton T-Shirt over the Sealing Iron>

[ujjwaana]

I knew I have some scope of improvement by 'Heat-shrinking' the covering (why they are named for). So I took out the hair dryer and blew some warm air over the both sides. Bo much of result.

Now it happened to me that I recalled the I have a 'Super Hot' Heat gun, which I bought from Mobile Repair supply shot, I used to shrink Heat Shrink Tube for wires. I was reluctant to use that on this otherwise fragile film, but when the work already looked shabby and trashable, I let give it a try.

Result - amazing. All the slack covering became Drum-Tight. I over did it at one corner where the yellow covering over shrunk into white.

Over all a good learning experience.

[VC]

The good old Gnome! Vintage...........aaaaah! Memories, memories, memories..........

Where can I get one of these?

[ujjwaana]

Haha! VC Sir i am planning to make gnome 3 Channel Powered. see how it goes.

Mr Sampath of "New India Hobby Center"  Bangalore should be having few. They are made by Aurora Hobbies Calcutta (Mr Sarkar ?). I paid something like Rs 650 for that. I can send one for you.

[flyingboxcar]

Ujj
Keep an eye on that tail. The structure is designed to take on tissue and dope. The polyester film if shrunk too much would warp it up.
The trick is to lay up the covering as tight as you can in the initial phase any take out any slack at the final phase after sealing the edges all around.
Heating the poly film beyond a certain temprature (aka. cooking the film) would give you beautiful results but over the time it will sag and then no amount of heat would take it out as there is no shrink left in the film.     

[TonyBeckett]

Only just found your post about converting your Gnome glider.
How did you get on?

I mentioned the conversion on
http://www.peterboroughmfc.co.uk/

Where I suggested an R/C conversion was needed on our Gnomes.

Tony