Wednesday, April 25, 2012

My Mother has a Blog! And Russian Mennonites build an Ultralight Airplane! In 1907!

Please note: James' blog has moved to a Wordpress site. To access it, please visit All posts have been transferred to the new site, and all new posts will only be accessible via Wordpress. Thank you for your interest!

Some of you know that my background is small town Mennonite (Hillsboro, KS), and a few of know that my mother is Katie Funk Wiebe, a retired but still prolific Mennonite author.  Mom writes her own blog, Second Thoughts, and I like to think that I got a good measure of her writing DNA.  I think the book count she's authored currently stands around 20ish.  And she's not done yet!

While having lunch with her a couple of days ago, she let me look through an excellent book on Mennonites, and was kinda stunned to see a 1907 photograph of some Russian Mennonites, standing next to a Wright-esque airplane (glider) they had constructed.  I have copied only a fuzzy photo, and leave it to you to surf to other websites which contain old historical information on this impressive Mennonite / Aviation accomplishment.

Imagine you are in Russia, 105 years ago, and you see this:

Wow.  !!

It seems this is the HUP airplane project at Chortitza, with HUP standing for Hildebrand, Unruh, and Plenert.

Excerpting from an online article, found at

...Launching a glider on the flat Russian steppes was as great a feat as designing and building one. The youths solved this by fitting HUP with skis to slide on grass and using two horses for launching power. A powerful stallion provided initial horsepower to overcome inertia and was then cut loose.  An exceptionally fast mare continued at a dead gallop towing the machine sufficiently high into the air to glide blissfully around until speed loss and lift forced the pilot to land.
...The HUP Project at The boys' efforts didn't always meet with approval in an agriculturally-oriented community with strict religious standards where the "man with wings" philosophy also predominated. Nonetheless, their efforts invariably drew a crowd. Sometimes the young gliders capitalized on this by charging admission and occasionally an adult donated to the project.
...By 1907 the men, aged 17 to 20, felt they had sufficient experience, knowledge and finances to try building a real plane. They abandoned the glider and set to work designing and building HUP II. They planned and built the fourThe cost was so high that they couldn't afford wheels and once again had to rely on

You can read one of articles here.

Fuel Sender Installation in Plastic Tank

Please note: James' blog has moved to a Wordpress site. To access it, please visit All posts have been transferred to the new site, and all new posts will only be accessible via Wordpress. Thank you for your interest!

Here's a quick way to get a fuel sender into any ultralight aircraft.  We've done this with aluminum tanks, by welding a 'platform' onto the tank for the fuel sender, but it's quick and easy with an inexpensive 5 gallon tank from Walmart.

Here's how.  Start with a fuel sender, which you can purchase from us or from Aircraft Spruce, which looks like this:

Fuel Sender

The fuel sender has three connections:  power, ground (+12v), and fuel sender output (provides 0 to 5v to fuel gauge.)

Of course, you'll need a fuel gauge.  Many different companies sell them.  Ours features brilliant adjustable daylight readable LEDs, and minimal power consumption, and absolute lowest weight (less than one ounce).  It looks like this:

fuel gauge from Belite

and it fits in any standard 2 1/4 inch instrument hole.  All you need to do is attach ground, power, and attach the input to the fuel sender.  (Use a 1 amp fuse when running power to the fuel gauge and the fuel sender.)

We also use a classic red 5 gallon tank from Walmart, and we drill a hole in the top for the fuel sender.  (We also drill a hole for the fuel line 'bobber' to feed through.)  The tank must be vented, and the 'slop' around the fuel line hole provides this venting.

It looks like this:

Fuel tank for ultralight with fuel sender hole drilled out.

We then place the fuel sender through the hole below the handle, and secure using five ordinary wood or deck screws.  We don't use nuts/bolts, because they are way too hard to get the nuts into the tank.  The gray material is a fuel tank sealer, which merely provides a gasket around the hole, to prevent fuel from sloshing out.  You can get it at your hardware store.

One of the neat things about using this kind of tank is that if you use a quick release fitting on the fuel hose, you can swap one fuel tank for another in your ultralight airplane.

After installation, follow instructions with the fuel probe for setting the empty and full positions on the gauge.

Sunday, April 22, 2012

How to assemble a truss structure rear fuselage on an Ultralight Aircraft

Please note: James' blog has moved to a Wordpress site. To access it, please visit All posts have been transferred to the new site, and all new posts will only be accessible via Wordpress. Thank you for your interest!

Assembly of a rear truss structure aluminum fuselage for a
Belite Ultralight Aircraft

It’s easy to assembly a rear fuselage for a Belite ultralight airplane!


Your kit should have the following items in it:

A)    Pre-riveted frames, constructed from 2024T3 aluminum, 7/8” x ½” x .063”.
B)     Longerons, with tabs already attached.  Also constructed from 2024T3 aluminum.
C)     Rear post, with pre-welded rudder hinge point. 
D)    Gussets.  Gussets are made from either .032 or .040 aluminum, 2024T3 or 6061T6.
E)     Truss pieces, constructed from 2024T3 aluminum.
F)      Rivets – commercial grade.  If you are interested in using aircraft grade rivets, we encourage you to purchase them directly from Aircraft Spruce, or the supplier of your choice.  We do not supply them.
G)    Top skin aluminum, pre-routed. 

Here is the pictures of the parts:

Section Frames, Six of them, A through F.
The frames are ‘A’ through ‘F’ as shown on the blueprings.  Each is riveted together.  All are easy to identify by comparison to the blueprints, with one exception:  One of these frames has a dimension of 19 by 19 1/8”.  Don’t confuse the vertical dimension with the horizontal dimension on this one frame; look carefully at your blueprints.

Longerons with gussets.
 The longerons come pre-riveted with gussets.

Truss sections.
 The truss sections are all labeled as shown.  You may also notice color coding, which we do to help you sort out where the truss and frames rivet together.

Rear post.

The rear post is pre-welded for rudder attachment.  DO NOT RIVET to the top of this post as it has to receive the vertical stabilizer, rivets would obstruct inserting the vertical stabilizer post.

 The gussets are obvious in use, especially after reviewing all photos.

*PLEASE NOTE that we are now using small triangular gussets INSTEAD of the small wrap-around gusset shown on the bottom right of this photo.*

Top skin, predrilled.
The top skin is also drilled and ready to rivet in place.


We recommend that you prepare your absolutely flat workbench with a centerline (denoting the center of the fuselage and positions for each of the frames.  You can see these lines throughout our photos.

The fuselage is built upside down.  The top longerons are placed on the workbench; the frames are riveted in place; everything is placed absolutely dead square to the workbench (90 degrees to the table top.)  Use squares, clamps, and whatever else you need to keep it all completely square.  Measure twice and drill once.

All holes should be de-burred.  It is our experience that the 2024 aluminum alloy makes very clean holes, with very little chipping or burrs on the edges of the holes. 

We supply commercial grade rivets with the fuselage.  There is no place on the fuselage that requires aircraft grade rivets.  However, if you encounter low quality commercial grade rivets, don’t hesitate to drill them out and replace as appropriate.  (As an example, you can tell a bad rivet by a non-uniform pull force.)

The entire fuselage may be reassembled, prior to riveting, using Clecos, which we do not supply.  Having the entire fuselage in its final form may provide you with a great deal of certainty that you are doing it correctly, but this choice is up to you.   If you choose to use Clecos, your fuselage project may look like this:
Clecos in use
And here is another pictures of clecos:

More clecos in use
 Let’s get to work on putting this fuselage together.


Lay the top longerons and small rear gusset plate on the work bench.  (Remember, this is upside down.)
Top longerons.
Now rivet the rear plate in place.  (We recommend riveting this plate in place, even if you are using Clecos.)

Rear plate and top longerons
 Place the “A” frame in place as shown in the photo, below.  Note that a cross brace has also been placed on this A frame; make sure that the A frame is absolutely square.   The cross brace supports load from the fuel tank, which eventually rests on the cross member of the A frame.  Use any aluminum for the cross brace.

'A' frame in place, along with cross brace
Rivets at base of "A" frame
 Rivet the A frame in place.  In the photo above, you can see a typical rivet pattern in the A frame.  Our gussets are now cut on our CNC shopbot and are much ‘prettier’ than shown above.

"A" frame centered on workbench and riveted in place
Note how the center of the A frame has been centered onto the workbench centerline.  Both sides are riveted in place.

Weight placed on top of "A" frame

A weight has been placed on the A frame to keep it from moving. 

Now, place all frames in place and rivet.  Note that all frames are exactly where they need to be, and we use weights to keep them in place.  The longerons are matched exactly with the beginning of our table (barely visible in lower left corner):
A through F frames in place
Rivet holds frame to longeron
Each frame is held by a single rivet at this time.  A second rivet will be drilled and placed, later.  The gap in the frame is expected, as shown in the above photo.  And although you can’t see it in the above photo, the rear of each frame has been beveled so that it will clear the interior of the longerons.

Additional longerons are then placed along the opposite side of each frame. 

Longerons on other side of fuselage

Rivets in gussets
The rivets are placed into the new longerons and frames as well, as shown above.  Everything needs to be square and line up, as shown in the photo below.
Fuselage view down center top
Fuselage view down inside
Rear gusset
The rear gusset is used to hold the longerons in place.  Note that rivets have been used to keep the longerons together, but the rivet pattern has not yet been filled out.

NOTE:  Taildraggers use FOUR of these plates (quadrupled thickness); tricycle gear aircraft use TWO of these plates (doubled thickness).
Rear post
 The rear post is also held in place temporarily with rivets.

Another view of rear post
Small Wrap gusset
NOTE:  the gusset in the above photo has now been replaced with two triangular gussets, one on each side.  It’s much easier to fabricate. 
Large wrap gusset
The other end of the rear post will accept the vertical stabilizer.  It is notched into the longerons, then held in place with a doubled wrap around gusset.

Figure 27  Rivets on wrap around gusset

Now it’s time to start adding truss sections, starting with the rear gusset, then moving forward to other frames:
Rear post with truss added

Another truss added

All of the truss sections are added and riveted in place:
All trusses in place
And one reinforcement is added, parallel to the rear post.  It is in the photo below, immediately flush to the rear post.  Because the rear post may not be riveted, this parallel structure provides compressive strength to the rear assembly.  

Rear post with parallel reinforcement.
Typical gusset; two rivets per frame
Each frame and gusset is riveted out.  Note that each frame now has two rivets connecting it to the longerons.

Big gusset on rear post
You will also need to flip the fuselage over and add the top skin. It is possible to place without clecos, but go very slowly, line it up very carefully, and make sure every frame and centerline is square.

Top skin in place.
After riveting, it’s Done!  And ready to attach to the fuselage cabin.

The rear fuselage must be covered with fabric (after assembly to cabin) in order to have adequate strength.  Make sure you review final assembly requirements prior to covering.