HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 28, 2012, 11:34 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
Hollow Boom

I just finished the boom. I already splitted the original one into 2 halfs with a balsa cutter. I bought 2mm plywood and copied 2 times the shape of the boom onto the 2 mm plywood. After I cutted 2 pcs, I cutted 2 slots out of the 2 pcs, so that I have 1 1.5mm space, just enough to lead the control rods through. I won't use outer tubes as I don't need them in this way. The control rods will just go through the hollow boom without outer tubes. In this way, I only need to remove wood from the boom as less as possible to keep strength.

The 2 control rods will be situated next to each other through the boom. I just used balsa glue, this will provide me some time to adjust and position the parts exactly without the risk of filling the hole with glue that will block the control rods later to get them through. CA would be good too, but will not give you the time to settle everything correctly while epoxy has the risk to fill the hole with glue that you can't remove lateron.
The result now is a very stiff boom. Stiffer than the solid boom was before. It has now a width of 8mm against the width of 7mm as before. That will reduce a bit due to sanding.
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 03, 2012, 12:00 PM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
Built-up Pod

It has been a few days ago since my previous post. That is not because I haven't done anything, I just wanted to wait and see if I was able to change the solid pod into a built-up one, and I think I succeeded.
I have added a 4 degrees angle of attack to the main wing. I have used 1.5mm plywood to make the formers. I also made a kind of removable cover that will give access to the RC equipment later.
Next job will be covering the pod with 1mm balsa stringers and add the nose that will contain the ballast to get the CG right.

Notice the push rods going through the formers. I made a small mistake, can anyone see what mistake I made? Can be easily fixed.

The result is very strong and stiff.
micheldeman is offline Find More Posts by micheldeman
Last edited by micheldeman; Jul 03, 2012 at 02:20 PM.
Reply With Quote
Old Jul 10, 2012, 06:12 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
The pod has been covered with balsa strips. Glued with CA works fine and fast, no need to wait until the glue has settled every strip that is to be glued.
There are about 60 strips used to cover the pod. From the inside, I have put CA glue in order to improve the strength of the covering, which appeared to be a bit weak. I have used soft balsa, better used some stronger balsa for covering.
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Jul 10, 2012, 06:14 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
Actually what you see above is a modified version of the pod of the Jetco thermic 72". A build-up pod giving the main wing an angle of attack of 4 degrees.
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Jul 21, 2012, 03:06 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
Elevator

I have adapted the rear lower part of the boom/rudder, so that the control rod for the elevator can pass trough it. The slot will house the horn for the elevator too.

I have adapted the elevator for RC use. I have splitted the elevator flaps in two parts, connected through a fiber rod on which the horn will be mounted. The horn will be inside the rear lower part of the boom/rudder.
micheldeman is offline Find More Posts by micheldeman
Last edited by micheldeman; Jul 21, 2012 at 03:16 AM.
Reply With Quote
Old Jul 21, 2012, 06:09 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
The tail/rudder is almost ready too. I modified the tail, I added an oval shape, pure a cosmetic thing, inspired by (copied from) this model. http://static.rcgroups.net/forums/at...512-253-J2.JPG
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Jul 22, 2012, 08:15 AM
Blueplaidcanard flyer
sdy. ny
Joined May 2007
2,978 Posts
I like the tail treatment should look real fine through the covering.
rabidrue1 is offline Find More Posts by rabidrue1
Reply With Quote
Old Aug 20, 2012, 05:56 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
I assembled the main wing parts together. I didn't chose to keep them seperated for 2 reasons. 1: it was easier just to assemble them rather than keeping them in 2 parts. 2: it's much stronger and reliable to assemble them together.

I have added a centre rib that wll become part of the canopy construction. I am going to apply the same kind of construction as for the pod, opposed to using solid pieces of wood as suggested by the design.

I am in the process of filling the top of the pod with pieces of balsa wood in order to get enough support for the wing rest. Finally, I will cover the wing rest with 1mm balsa wood.
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Sep 10, 2012, 01:33 PM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
I have finished the wingrest and covered with 1mm balsa.
I also have glued the tail on the boom.
Here are some pictures of the progress.
I only need to make a support for the stabilizer and cover and fix the nose filled with weight to the pod.
Then I need to install the RC equipment and lead the control rods through the boom. As you may remember, I made up the boom out of several parts so that it is hollow inside.
Then to cover the model. I am going to use probably just tissue. It is the lightest option and gives the most strength to the wings, it's only very fragile to dammage when punctured by sharp objects like dried grass straws.
micheldeman is offline Find More Posts by micheldeman
Last edited by micheldeman; Sep 10, 2012 at 01:42 PM.
Reply With Quote
Old Sep 10, 2012, 01:50 PM
"Butchering Balsa since 1971"
CashRC's Avatar
USA, TX, McKinney
Joined Dec 2003
1,054 Posts
Very, very nice. I grew up with Jetco kits in the late 60s and early 70s, so they have a special place in my heart.
Again, top-notch work.
Cash
CashRC is offline Find More Posts by CashRC
Reply With Quote
Old Oct 02, 2012, 10:31 AM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
Okay guys,

here it is, covered in tissue with coloured trims,

not bad if I may say so,

thanks,

Michael
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Oct 02, 2012, 01:02 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,650 Posts
Very classy!
Sundancer is online now Find More Posts by Sundancer
RCG Plus Member
Old Oct 02, 2012, 10:38 PM
Dog is my co-pilot
brokenspar's Avatar
Joined Jan 2004
1,005 Posts
Nicely done!
brokenspar is offline Find More Posts by brokenspar
Reply With Quote
Old Aug 22, 2013, 02:28 PM
Registered User
United Kingdom, England, Coventry
Joined Apr 2012
81 Posts
After being stored nearly one year after completion, my jetco thermic 72 went out into the sky.
It's flying fine and is very stable, I have had a many thermals already and it's even capable of doing some manoeuvres including loopings. The rudder is very efficient as well as the elevator.
I have been out flying twice now and the floater is really giving fun and satisfaction of the effort put in it during the build. Also the looks are great, especially the double dihedral and bird shape of the main wing is awsome.

See below for 2 videos:

2ch rc converted 50's Jetco Thermic 72 free flight floater / glider (3 min 18 sec)


Jetco Thermic 72 going into thermal (2 min 13 sec)


have fun,

Michael
micheldeman is offline Find More Posts by micheldeman
Reply With Quote
Old Aug 22, 2013, 06:27 PM
Registered User
United States, NY, Ithaca
Joined Sep 2007
906 Posts
Great job, and a great conclusion...congratulations! I especially liked the planked pod and the soaring flight videos.

Jim
buzzard bait is online now Find More Posts by buzzard bait
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Found Jetco G-4 THERMIC 72 Towline Glider Model Kit or others. Beardiedrg Aircraft - Sailplanes (FS/W) 3 Jun 10, 2012 02:52 PM
Sold JETCO Thermic 50-X $100 shipped conus wing881 Aircraft - Fuel - Airplanes (FS/W) 0 Mar 20, 2012 12:35 AM
Sold JETCO Thermic 50-X $100 shipped conus wing881 Aircraft - Sailplanes (FS/W) 3 Dec 26, 2011 06:53 PM
Sold Jetco Thermic 72 Pod & Boom by TMRC Buran Aircraft - Sailplanes (FS/W) 1 Oct 27, 2010 04:53 PM
Discussion jetco thermic 72? balsabozo Slope 6 May 11, 2006 12:06 AM