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Jay Burkart's blog
Posted by Jay Burkart | Mar 05, 2011 @ 01:37 PM | 6,844 Views
I have been working with the stringers for the bottom side of the fuselage cowling.
After doing that part the fuselage has a bottom keel that runs about 3/4 the length of the fuse.
This also is the area where the landing gear exits and the bottom hatch is fitted into the fuselage.
The landing gear exit is relatively straight forward just a 5/32 gap between formers to allow the gear wire to exit and allow for pulling the gear out if needed. The hatch in the bottom is a bit more involved because of the flat bottom of the fuselage superstructure and then the angular keep shape over that. Also the fuselage bottom is on a curve at the point the hatch needs
to be place, then there is a hatch latch needed to release the hatch..
The hatch needs to be relatively long to allow to move the battery pack along it to allow for CG adjustments when motors are changed due to their difference in weight....Continue Reading
Posted by Jay Burkart | Feb 26, 2011 @ 07:58 PM | 7,071 Views
Got all the sides joined and started finishing the insides of the fuselages. Slide in Landing gear mounts, Wing Trailing edge wing mount reinforcements,
stringers for cowling.
All are mounted in all three. We are setting up with 5/32 landing gear wire as the
targeted flying weight will be 114 oz to use the 1900mah 3S lipos.
Probably 10 to 18 oz of ballast will be needed to make the weight rule.
I am guessing that the finished weight with all the gear will be around
100 oz for the LMR and 96 for the Texaco.
That will bring us close to the 10 oz/sq ft target....Continue Reading
Posted by Jay Burkart | Feb 23, 2011 @ 09:21 PM | 6,254 Views
I have made all the side pieces of the fuselages and have them ready to be joined
Also the wedge piece at the very tail of the fuselage is glued to one side before
joining the sides, it is a piece of 3/8" x 1.5" Trailing edge. The notch is to clear the rudder mounting
screw going up from the bottom the the stab and the other notch is the hardwood crossmount for
the horizontal stab itself. Also is shown how I sand the sides flat.
A Sanding T with the fuselage side pressed against a sanding board
with sandpaper attached to it.
Posted by Jay Burkart | Feb 08, 2011 @ 11:19 PM | 7,008 Views
I have been building fuselage sides for the last several days.
Cutting this lumber in this fuselage requires sawing each piece as a knife nor razor blade
can't cut through this lumber.
And there is a lot of cutting and fitting of all the longerons, uprights, gussets etc.
Right now I have 4 side completed and the 5th is on the board.
Six sides are needed for the 3 Airborns under construction.
With variance in wood sizes you can't really cut all the parts and just fit it together.
Each side is unique and has to be fit together.
I should have the side done and ready to sand in a day or two.
My Dremel saw and 12" sander are my best tools.
Also the pieces are so thick that you can't build one side on top of the other....Continue Reading
Posted by Jay Burkart | Feb 03, 2011 @ 07:18 PM | 7,599 Views
Finally got my saw and a start on the fuselages.
I have been making some of the cut pieces with exact angles and wing saddles
for the fuselages. A lot easier now that I have a small Dremel 4" saw.
The one picture is how I cut out the wing saddle so that the wing sits at
1.25 Degrees positive angle of attack, the stock Airborn is set at about 5 deg
which is way too much for RC flying and good thermaling characteristics.
I have proven this angle after now building 31 Airborns over the last 4 years.
I also have the Horizontal stab so that I can change it's angle if needed but
with settling on the 1.25 deg on the wing I haven't needed to trim the H Stab.
Posted by Jay Burkart | Jan 20, 2011 @ 07:29 PM | 6,640 Views
They are ready to cover.
What is left is installing the LE pins when mated to the fuselage
and the trailing edge wing bolts will be drilled to mate to the fuselage.
The ply reinforcement for these are installed at the center trailing edge.

The wings have a span of about 9 ft 5". Darn, I was trying for 10ft.
The Chord is about 16"
I can't even stand the darn things up in my shop.
You can hide behind these wings.
Hold them over your head in a breeze and you'll be airborn.
They look good if I do say so.
Now, hide all that pretty jointery under covering, how sinful.
I will start on the fuselages soon, still waiting on my new saw.
Posted by Jay Burkart | Jan 17, 2011 @ 06:46 PM | 7,219 Views
Having done the wing bisection the root panels need 1/16 Ply end cap ribs.
These are epoxied on and then sanded to conform exactly to the midsection sheeting.
Best tip on doing this is to put painters tape around the root of the wing section to
keep the epoxy from getting over on to the sheeting and also as a tell tale for when
sanding the cap rib to be flush with the sheeting.
Hold the tape about 1/16 back from the joint so that the epoxy does not glue the
tape in place, I also paint the epoxy on the ply rib with an acid brush that has
it's bristles shortened so that they are stiffer and can more effectivley brush out
the epoxy.
Next is the install of all the 1/16 ply dihedral braces on the Spars, Trailing edge
and leading edge.
There is a lot of cutting a fitting here and a pattern is cut from balsa first and then
traced onto the ply and all the braces are cut out. Make sure that the outer
ply grain is horizontal. A lot of even the aircraft ply now days is only 3 ply and
the two outer layers are in the same direction....Continue Reading
Posted by Jay Burkart | Jan 15, 2011 @ 09:02 PM | 6,828 Views
Cut all the midsections into two pieces right down the center line, through the joiner tubes
and into two equal parts with tubes perfectly aligned and ready for plywood end cap ribs.
One picture shows the cut through section with a 1/16 Ply end cap rib not the joiner tubes
showing through. A carbide blade cuts these tubes very well.
Then we cut the dihedral angle on all the the midsection tip ends and the matching
angle on all the wing tips. Nothing like a radial arm saw to do this with a nice 80 tooth
carbide blade for a slick cut. Also I made a little jig to align the tips for a square cut.
Just basically a wedge of 3/4" wood cut at the complementary angle of the tips
leading edge angle and trailing edge angle.
With all the dihedral angles cut on all the pieces we primed all the raw ends of the
parts like spars, Trailing edges and leading edges with thin CA.
Then I used my wing dihedral joining jig to match all the midsection halves to their
respective tips. Easy to line each wing panel up and joined.
Next will be the dihedral braces and ribs at the joints, also epoxy on the end cap ribs....Continue Reading
Posted by Jay Burkart | Jan 13, 2011 @ 09:36 PM | 6,785 Views
A bit more progress on the Wings.
The center or midsection of the wing has to be prepared to cut it into two right in the middle
to make two sections that will plug together.
So the wing has to be esentially covering ready through the entire middle section and then
it is cut into two halves on a radial arm saw.
This will mean cutting all of the structure including the joiner tubes.
Also in the middle section the TE is prepped for where the mounting bolts are installed
very near the TE a little bit off the center line.
Also you see the locating holes at the LE for the CF pins.
These go into the ply reinforced ribs on eithes side of the center.
I hope to be cutting the wings in two in a couple of days.
Then the tips will be joined onto their respective half of middlesection.
Doing the joined wing this way allows for quicker build and also the two
sections will exactly mate as they were built as one and then cut down the middle so both sides will match....Continue Reading
Posted by Jay Burkart | Jan 03, 2011 @ 10:14 PM | 5,712 Views
Made a bit more progress on the 1600's
Got one set of the tips rough framed and the other 2 sets should be easy.
Nothing special on these, just have to take in account that I build the wing joint from the midsection to the tips different than in Jim O'Reilly plans.
Since I do not use plug in tips like are on the plans.
Posted by Jay Burkart | Jan 01, 2011 @ 08:19 PM | 5,713 Views
I have framed up all three midsection wing panels.
This is the shear webs on the midsection with 1/16 balsa vertical grained on the outer 6 panels and
1/16 Plywood with the outer Plys in vertical grain for the inner panels.
Also the locating pin tube socket for the center section joiner.
This is toward the TE of the wing and is a tube that accepts a 1/8" music wire pin.
Note the sandwich of three ribs for the center section. The middle ribs is 1/8" to allow for
the kerf of the saw blade when I cut the center section in two parts later on.
Posted by Jay Burkart | Dec 28, 2010 @ 11:31 PM | 5,261 Views
This is the framing of the midsection of the Airborn 1600 Wing.
This has the wing joining system and alignment pin.
The framing has a kerf spacer right in the middle to allow for the width of the
blade when I cut the wing in two with a radial arm saw.
Note the end plugs installed on the joiner tube in one step so that the joiner
Carbon fiber rod does not just push all the way through the joiner tube.
The tube is installed at this time without the Carbon Fiber rod so as not
to cut it in two when cutting the wing section.
Posted by Jay Burkart | Dec 27, 2010 @ 05:28 PM | 4,125 Views
Made a little more progress on the Airborn 1600's.
I made the fastening system between the Horizontal stab and the Vertical stab.
I have done this fastening system for quite a few years now and have not had any problems.
Used a 1/8" carbon pins in the front bottom corner of the Vertical Stab where it goes into
a socket at the middle of the Horizontal stab. The Horizontal stab on this model has a 1/16 plywood
bottom at the bottomed of the slot to give it some extra strength and a seat to where the
rear 8-32 nylon screw pull the rear of the Vertical stab down and in.
The carbon fiber pin goes through a piece of hard balsa and the H. stab leading edge which
are also hardened with thin CA. The CF pin goes about 1" up and into the V. stab and is held
in with thin CA also. The thin CA will wick up and around the pin all the way and really holds
very tight, better than an epoxy joint.
Posted by Jay Burkart | Dec 22, 2010 @ 09:08 PM | 3,926 Views
This is still prep work for building the wings.
Two of the center section ribs, one on either side of the CL are doubled with 1/8 aircraft plywood
to reinforce them for the wing mounting pins of 3/16 carbon fiber that will stick out the leading
edges into a bulkhead on the fuselage.
So you see the 1/8 ply sub ribs. Also the spars are doubled at the center section
to make the wide enough to support the 3/8 OD brass tube that is the socket for the
Carbon Fiber joiner tube. The spars will support Plywood shear webbing in support on
either side of the brass tubes as the joiner tube "box".
Also the joiner brass tube is shown how it is roughed up for very good adherence to
the epoxy that will be used to join the box sides together.
Also you see the joiner tube with the holes drilled for it through the center
section ribs giving it's location between the main spars. This is just given
as an idea of how it will go into the ribs.
Posted by Jay Burkart | Dec 16, 2010 @ 08:36 PM | 4,206 Views
Attached is some progress from the last couple of days.
Started the wings,
Cut all the 1/4" sq Spruce spars and started bonding the .014 Carbon fiber onto one side.
Trimmed, sanded and adjusted all 126 ribs to fit the new deeper spar because of the Carbon fiber.
Glued up the wing tips.
Will be bonding Carbon fiber to all the spars for quite a few days.
There are over 24 spars.
I sand all the pieces before I glue them into the wings. Makes final sanding of the wing
so much easier and the fit is better.
Also gets rid of the burn marks on the edge of all the Laser cut balsa.
Still need to get 8 more pieces of Spruce in for the spars.
Need to cut and notch all the Trailing edge and cut the LE pieces.
The wings on these Airborn 1600's will join in the center with a carbon fiber rod
very similar to how the wings join on the large winch launch sailplanes.
Posted by Jay Burkart | Dec 14, 2010 @ 11:04 AM | 3,839 Views
Decided to make some more Airborns for SAM Electric and Texaco events.
Three of this size Airborns this time.
I have built 28 Lanzo Airborns so far. Lets say I can't get too much of a good thing. From 1/2A 280 sqin, now up at 1600 sqin.
Jack Hiner had Jim O'Reilly and Bob Holman make up some Airborn 1600 plans and short kits.
Got started a couple of days ago and I am making progress.
Building season is here and the wind and snow are blowing outside the shop door. I really like to build and like helping out my SAM buddies.
These are some quite large models even for SAM but if we can get a good power match up, these should be very competitive.
For the most part the larger a well designed airplane is for SAM competition the better they perform in lift and LIFT is what it is all about in the type of
competition SAM events are.
Find the thermal, climb and Soar is the name of the game.
Also the larger the model the easier it is to see and altitude, We often have these Airborns flying up at 3000 to 4000 ft in competition which is verified by the onboard Altimeters we carry, at that height they get mighty hard to see and seeing them and how they are flying is crucial.

Here is a build log for these Airborns
Posted by Jay Burkart | Dec 13, 2010 @ 08:04 PM | 3,436 Views
OK, enough grief and self pity.
Back to work.
Been building a number of SAM competitions airplanes.
Built a Airborn 280 sq in for Speed 400 LMR for Hank,
Built two Heeb Wrens's at 134 Sq in for SOS, one for me and one for Hank.
Got them both all framed up and ready to cover, waiting on Hank to get his servos and connectors squared away.
May be able to crack the 4oz RTF weight. Maybe one will come out
at under 3 oz RTF.
Also finished up and covered a Super Buccaneer for Jack.
All I have to do it to put on the tail feathers now.
In the last week started on 3 Airborn 1600 sq in. Got the Vertical stabs and Horizontal stab finished.
My gosh they are big, the stab alone is over 3 ft span.
Posted by Jay Burkart | Oct 30, 2010 @ 03:19 PM | 3,350 Views
Well the Champs win was a high point.
Now, not so happy.

Hobby Lobby decided that they didn't need me as a techsupport person anymore after doing that for 3 years for them.
I used to answer all of their email and web based questions also answered their forum questions.

I was a contracted person supplying a service for them, so they just
ended my contract.
I have been working with them and the former owner in one way or another
for 28 years.
Now I am looking for some kind of support role for another company.
My entire career has been in customer support and customer product
support including retiring from Hewlett Packard after 29 years of field support.

In the meantime I am earning a little extra money by building models for friends. I have just finished an Airborne 292 sqin and have started 2 WREN SOS models and have lined up to build 3 of the 1600 sqin Airbornes for
some of the other SAM guys. I am also finishing a Super Buccaneer hangar queen for another friend.
I stick build all of these models and do an excellent building job if I do say so.
Right now on the Airborne models, I have built 27 of them so far in different sizes and have sold 12 of those so far the other 5 are my current SAM competition models. Others went on trade etc.
Sometimes I wish there was a way to make a regular income of building models but no one wants to pay what there is in labor in the models.
But it keeps me busy and pays for my models and developing new setups for competition.
Posted by Jay Burkart | Oct 02, 2010 @ 07:17 PM | 3,430 Views
I had a great SAM Championships this year

I won The Electric Grand Champion for the third time, Previously in 2004 and 2007.
Seems like every third year is my good performance year.

Of the 5 electric events:
Won SOS and Speed 400 LMR event
2nd in Wakefield and LMR
3rd in Texaco

My Airborns and those of my buddies flew really well.
Seems like the design that has come into it's own.
Besides the one's flown by my buddies there were a bunch of them
competing this year both in Gas and Electric.

I have built 25 Airborns so far since 2007, got it down to a science in all the various sizes.