Thursday, August 25, 2011

Phenomenal Performance from Yellow Aluminum Ultralight

You'll get three things from this post:

a)  I can't stop glowing over the phenomenal experience I had flying our aluminum prototype airplane.  It was configured with a 28HP engine and the performance was very close to what we've experienced with our 50HP airplanes.  The reasons why this all worked:  light aluminum construction, a big wing with an awesome low speed coefficient of lift, (bigger span, bigger chord), bigger flaperons, and the exact right prop/engine combination.  I took a GPS chart on my phone of the flight and will try and figure out how to post it.

b)  I can't stop glowing over the phenomenal experience I had while practicing off-field landings in the next door hay field -- my able assistant Gene captured the STOL landing to perfection.  I cranked in two notches of flaps and nailed the touchdown spot within 15 feet.  After rolling to a stop (and I didn't use maximum braking), position was noted. Gene and I went and measured the touchdown roll with our tape -- 100.5 feet (that's 100 and one-half foot) from touchdown to stop.  The landing was made full stall (and was nearly full STOL, for those that grok the difference) and the plane dumped onto the hay from about a foot or two off the ground.  The steel spring gear just absorbed it all, you can see the tailwheel disappear into the grass in one of the pics that Gene took, and nuthin' bent.  Just saying.    Oh My what fun ------ Steve you will like your plane.

c)  The plane is really pretty.

That's three things.  Here's picture proof.  Let's start off with three pictures of the plane just flying around.

Belite's Aluminum Ultralight Aircraft flying overhead

Belite's aluminum ultralight aircraft

Belite's aluminum Ultralight Aircraft, passing under the sun

Now let's look at that landing sequence, showing short final into the hay field with the 100 foot stop:

Belite's aluminum ultralight aircraft, short final to the hay

Belite's aluminum ultralight aircraft, short final abeam the trees

Belite's aluminum ultralight aircraft, closer to the hay

Belite's aluminum ultralight aircraft, 25 feet up


Smack that tail down

Rolling through the hay

Already stopped!!!  Turning

Yeah Gene, I did it.  :-)  Nothing broke. 

One final pic after I taxiied back around the field and up the runway..

Pretty Plane, Awesome Performance, I like it...

Wednesday, August 24, 2011

Service Bulletin 8-24: Rod End Bearing needs cap washers

We had a partial failure on a rod end bearing, on a lift strut.  The point of failure is where the lift struts attach to the fuselage.  The internal structure of the rod end bearing began to fail, and as a result, the rod end bearing might have slipped over the head of the bolt.   If this had happened, there is a strong possibility that the lift strut might have detached from the bearing bolt on the fuselage, with damaging or catastrophic results.  A simple solution is the addition of a cap washer.  We recommend immediately adding these washers to your aircraft before further flight.  It is important that the top washer is trimmed so that it does not hit or rub the lift strut. 

Failed Lift Strut Rod End Bearing

Another view of Failed Rod End Bearing
In order to prevent these rod end bearings from slipping over the head of the bolt, we are installing cap washers:

Cap Washers, with one trimmed
Here is a photo of the reassembled lift strut attach point, showing the rod end bearings and the cap washers.:

Cap Washers installed on lift strut

The bolt has been reinstalled, complete with quik release key (safety wire is of course also acceptable).

If you need these washers, please contact us and we will supply them at no charge.

The integrity of the rod end bearings should be inspected with each preflight.

Nice Mythbuster Article posted

Carrie Rengers of the local newspaper posted a nice article online about Belite, myself and Mythbusters.

You can read it here.

Tuesday, August 23, 2011

Rear aluminum fuselage assembly

Here's some photos showing the buildup of the rear of the fuselage in our aluminum ultralight airplane.  Most of the aluminum is 2024 series, but some is 6061.  The amount of labor to get to this picture is about 20 hours.  Still remaining is gusset work, along with a few odds & ends. 

I love clecos!

This is not hard work.  It is a blast to lay it out and have it look like an airplane within two days.

The rudder comes pre-welded, as shown in the photos.

I'm in this picture, but you can't see me.  I'm holding the board up from behind.

Gussets not shown.  The bottom wedge with all the clecos is actually 4 layers of aluminum.

I love the rear section of the fuse.

This bulkhead will have the nylon bearing block for the elevator push pull tube.

Gas tank platform.

One last look at the tail.

Sunday, August 21, 2011

aluminum fuselage update

Here's some photos showing some of the ways our fuselage design has mutated from 4130 steel.  I've also made some comments on strength.

The front of the fuselage is made from 6061T6 aluminum, and is welded.  The rear of the fuselage is made from 2024T3511 aluminum, and is riveted.

The hallmarks of this design is that it is very light, very strong, and easy to assemble.  Let's look at some pictures.  The first picture shows that the primary vertical members are 1.0" aluminum square tubing, with .063" walls.  Although the temper is 6061T6, the welding is assumed to reduce the strength.  This particular tubing doesn't have the heavy loads.  However, it is also a primary safety mechanism to enclose the pilot in the event of an accident, so we still want it to be strong.  Assuming 0 temper, the strength of this material is about 4,500 pounds per tube cross section.

1" square tubing used in Belite ultralight aircraft  

The front section of the fuselage is where the engine mounts attach.  We've reinforced this section with 4" gussets.  Here is a gusset at the top of the front fuselage:
Gusset reinforcement

 And here is a gusset on the bottom of the front fuselage:

Gusset reinforcement is on bottom of fuselage  

Now let's look at the front spar crossover.  It is constructed of aluminum tubing (about .080 wall) with reinforcements in both axis.  As a result, it has a critical length of about 12 times its diameter, which means that the effects of "Euler's Buckling" have been reduced or eliminated.  At normal loading, this spar crossover has about 650 pounds of force pushing through it.  At a 4G load, it would have around 2600 pounds of force.  Assuming 6061T0 temper (welded), the cross section strength of this material is about 4000 pounds.

Front Spar Crossover with reinforcements.

Now let's take a look at the rear spar crossover.  We've reinforced it with some 1" square material.  The failure strength is substantially stronger than the front spar.

Rear spar crossover with reinforcement   

Here's another view of the rear spar crossover:

The above photo shows the bracing.  The braces help prevent the cockpit from torsionally twisting.
rear spar crossover with bracing shown
The pilot's seat also gets some strengthing:

0.5 x 1.0 aluminum tubing added to pilots seat
Tricycle gear versions of our planes get extra cross channels on the bottom, along with more bracing in the side cabin area:

Tricycle gear airplanes get even more cross channels 

And now let's show how the rear fuselage is added on.  We start with four longerons built from 2024 aluminum, with an angle size of 0.875 x 0.5 x 0.063 inches.  We then add some bulkheads, a vertical stabilizer, and some rivets.  We also use gusset plates.  Since there is no welding in the rear of the fuselage, the 2024 is an excellent choice.  (You can't weld it, but good golly goodness is it strong.)  Tensile strength of the longerons is off the charts:  each longeron could lift nearly 5900 pounds.  In a few more days, I'll have some photos of the completed rear fuselage.

Rear fuselage of Belite's aluminum airplane

rear view of the rear fuselage of Belite's ultralight aircraft
front view of the fuselage, it's all coming together