Wednesday, December 29, 2010

Installing a gas tank in an ultralight aircraft (such as the FAR Part 103 Belite!)

Another easy task is mounting our 5 gallon, spun aluminum gas tank in our ultralight aircraft, the FAR Part 103 Belite aircraft.  These tanks weigh less than 5 pounds, are extremely rugged, and are painless to mount and use.  They are clearly preferable to heavy plastic tanks used on certain earlier ultralight aircraft.

(If you are new to this blog, you'll find several other detailed construction posts on other topics [such as building carbon fiber wings].  Just poke around the search box until you find them.)

The major component of this tank installation is the aluminum tank.  We use an off the shelf 'dune buggy' style tank.  They are available from many different vendors online.

Before starting installation, consider the usage of a fuel sender -- this requires tank modification before

Tuesday, December 28, 2010

Attaching Flaperons to an Ultralight Aircraft (such as the FAR Part 103 Belite Aircraft)

I hope you've had a great Christmas season!

In this continuing online assembly manual, we'll attach our flaperons to the wings of our ultralight aircraft, the FAR Part 103 compliant Belite.    This assembly procedure is designed for our Belite aircraft, but the procedure is educational for any ultralight aircraft builder.

This is easy:  all we need to do is to clamp the flaperons in place using vise-grips; a couple of alignment templates make accurate alignment very easy.  After everything is lined up, the flaperons are bolted in place using AN3 hardware (bolt, washers, nylok nuts).

Here's the view looking down the flaperon, with three vise-grips already in place.

Tuesday, December 14, 2010

Belite Batteries demonstrate their power!

There are many things to do in preparation for the first public showing of our electric airplane. 

(I call the plane the Electric Lite.)

One item on the preparation list is a battery test.

There's nothing like a bunch of very high capacity lithium batteries to put smoke into a building when showing their power during a discharge test.  That's exactly what happened when we first tested our batteries, about a year ago.  Here's the video we made at the time, which has never before been seen or posted:

Some of the technical details of this battery test are contained within the video.

It's not much to look at -- just batteries, enormous dummy load resistors, a lot of smoke, and a room that got warmer and warmer as the test progressed.  But maybe, just maybe, you'll enjoy looking at it and wondering:  what is Belite up to?

Please watch and enjoy!

If you want to receive formal information from Belite on our electric airplane, you must register here.

If you are interested in partnering with Belite in electric aircraft development, please correspond with me directly:  james at beliteaircraft dot com

Monday, December 13, 2010

Sneak Pictures of Belite's Batteries

Earlier today, I had a conversation with my marketing manager, Kathy.  She also happens to be my wife and business partner.

"I think I'd like to start posting some more information on my blog concerning our electric airplane design," I said.  "But I won't really release any information -- I'll just create some teasing posts which show elements of our design.  Then, when we're ready to announce our progress more formally, we'll hopefully have more people attuned to what's coming."

Kathy said that sounded like a fine idea.

So, without further ado, here is a photo of a battery pack I found lying around our production facility:

LiFe04 Battery Assembly at Belite Enterprises
This particular battery is part of an electric battery system with the following selected characteristics:

Monday, December 6, 2010

Magazine Does a Photoshoot of Superlite

I enjoyed the experience of being a part of an aircraft photoshoot. It's even more interesting when you're flying an ultralight aircraft!

The photo session had several parts:

a)  Some fly-bys, down the runway, to the left and the right of the photographer.  My objective was to keep the wheels one feet off the runway, and to keep a wingtip over his head as I passed by.  I was free to start a pullup when I was within 100 feet of him.

Saturday, December 4, 2010

Building a Carbon Fiber Wing with Aluminum Ribs - Part 2

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This is the second part on our online tutorial of how to build a carbon fiber wing.

Our objective is to have a truly great ultralight aircraft - our FAR Part 103 Belite Aircraft.

The first part of this assembly document may be found by going to this link. 

I have completed my online updates to this wing assembly manual.  Further updates may be obtained by purchasing a kit, and receiving the printed wing assembly manual.
Building a Carbon Fiber Wing with Aluminum Ribs - Part 2

Last Updated December 13
Updated December 7
Updated December 4
Updated December 2

16.  Installing the Sail / Anti-sail tubes

The photos in this section show the sail / anti-sail tubes without Zinc Phosphate primer.  The primer will be

Sunday, November 28, 2010

Building a Carbon Fiber Wing with Aluminum Ribs - Part 1

Building a Carbon Fiber Wing with Aluminum Ribs - Part 1

A completed wing.  It weighs 20 pounds. 

Last Updated December 13, 2010

I have finished my online edits to this revised wing assembly manual.  Further edits are contained within the latest version of the builder's manual, included with each kit.  No further online edits are planned at this time.

Updated December 7, 2010
Updated December 4, 2010
Updated December 2, 2010
Updated November 30, 2010
Updated November 28, 2010


When you are done with these wings, you will have state of the art ultralight aircraft wings utilizing carbon fiber and aluminum.  They will work well with our FAR Part 103 Belite Aircraft!  The weight of the left wing (without flaperon or covering, but including the flaperon control cable and pitot tube/tubing) is slightly less than 20 pounds (9.1KG) when complete.  The weight of the right wing is 19 pounds (8.6KG).

Construction is straightforward, requiring only the ability to accurately place and glue parts together, with minimal riveting and absolutely no welding.

If you are building with aluminum spars (instead of carbon fiber) and wooden ribs (instead of aluminum ribs), you will only need to make slight modifications to the build instructions to complete your wings.


First of all, check your materials.  For each wing, you should have the following:

a) QTY 2 Carbon Fiber spars, with pre-attached CNC Machined lift strut hard points
b) QTY 5 Aluminum ribs
c) QTY 2 Birch Ply ribs, CNC machined from 1/2 inch Birch plywood (for root and tip caps)
d) Aluminum Tubing - 6 inch (length) used for doubler for spar roots
e) Aluminum Tubing - 1.5 inch (length) tripler used for spar roots
f)  Aluminum Tubing - 0.5 inch OD x 0.035 wall thickness, 6061T6, used for false rib spar and sail/anti sail braces.  A total of 5 tube lengths of varying lengths are needed for sail/anti-sail tubes.  12' is needed for false rib spar.
g) Aluminum Tubing - 0.625 OD square x 0.035 wall thickness used for rib stiffeners and sail/anti-sail hard points
h)  Aluminum Sheet - 0.025 thickness used for front spar strap, you will cut to 10" by 0.5" straps.
i) pitot tube - 1/4 inch aluminum tubing, prebent to shape.
j) plastic tubing for pitot tube
k) QTY 2 machined jury strut attachment fittings
l) preformed trailing edge aluminum, 12' per wing
m) LEFT and RIGHT CNC machined flaperon control cable dropper
n) one 3/16" rivet for trailing edge attachment to wooden root rib
o) 1/8" rivets for rib strips and for trailing edge attachment
p) 1/8" rivets for spar doubler/tripler
q) Carbon Fiber rope for securing jury struts
r) cotter keys
s) wing blueprint

You will need the following materials to finish your wing kit:

a) Glue (3M 2216) is NOT SUPPLIED.
b) Zinc Phosphate primer is NOT SUPPLIED.
c) Epoxy (West Systems or equivalent) is NOT SUPPLIED.
d) Acetone for glue cleanup is NOT SUPPLIED.
e) Sandpaper / Scotchbrite is NOT SUPPLIED.

Also note that flaperons and flaperon cables are NOT SUPPLIED with this kit.  You will need to order them separately.  (Or hopefully, you bought a complete kit.)

Also verify that you have a flat, absolutely flat workspace for building the wings.  The workspace needs to have easy access to a complete wing assembly, which has dimensions of about 12 feet by 4 feet.  You'll also need all of the usual tools (aviation snips, sandpaper, rivet squeezer, mixing trays, small paintbrushes...).  Having a large quantity of right angle squares and small clamps is essential for building a square wing.


2.  Spar Assembly.

Using very light sandpaper, clean and rough up six inches of the root portion of each carbon fiber spar, in preparation to glue on the 6 inch aluminum doubler.  Ensure that the doubler will fit over the spar.  This is what it will look like after the doubler and the tripler and the root rib are glued together, but don't glue anything yet:

Doubler, Tripler, Rib and root rib, along with some sloppy glue.  Don't glue it yet!

3.  Wood Rib Preparation.

Paint each of the two end cap wood ribs with a very light coat of epoxy.  This will ensure decades of life.  Lightly sand as necessary to remove excess epoxy and for better appearance.

Root Rib, in place.  It has been coated with a layer of clear epoxy.

4.  Aluminum rib strap preparation.

Cut 5 strips of 0.025 aluminum to dimensions of 1/2 inch x 10 inches for each wing.  These will be used to attach the front of the aluminum ribs to the leading edge spar.  A total of 5 straps are needed for each wing.  Clean and rough up using Scotchbrite, then spray coat with Zinc Phosphate primer.

Saturday, November 27, 2010

Hot Air

While working at the shop this morning, a hot air balloon landed on the runway.

I'd been working on a carbon fiber wing spar, and noticed an unusual hissing/burning sound from outside:  just like a propane heater being turned on and off.

Walking outside the shop door to investigate, a balloon floated and touched down mid-runway!

Fun!  A couple of us airport guys watched and talked with the pilot and crew as they loaded the balloon into their chase pickup.  The winds were calm, so they used a little envelope heat to help lift the balloon into the back of the pickup.  The balloon was then tilted over and collapsed.

Tuesday, November 16, 2010

Trike Test Flight; Pup Show Up

Today, while testing a customer's yellow trike, another ultralight showed up.  I played with him; not sure if he really saw me.

What a nice day to fly!  Light wind; clear skies; fall colors; 

Wednesday, November 3, 2010

Harley Up For Sale

We call this plane 'the Harley'.  Love the gorgeous orange and black!

Weighing in at 243 pounds, it's a beautiful ultralight.  We've got it flying with a MZ-34 engine with electric start.

Available for immediate delivery, it features our  Belite 254 design, with full fuselage fabric covering and bright orange paint.  The panel is 'steam gauge', and it is beautiful stained wood.  The wing has aluminum spars, and the lift struts are aluminum/carbon fiber.  The black powdercoating plays beautifully against the brilliant orange paint!  We've also added an aluminum engine cowling with bright chrome trim.

Priced at $24,995 + the following options:

Brakes -- $250
Steel Spring Gear -- $350
Electric Start -- $299
Full covering -- $1000
Full Paint -- $2950

FAF -- $29,844.

Pictures are below.  Enjoy!

Thursday, October 21, 2010

Deadstick Landing! "Don't try this at home".

1.  "Don't try this at home."
2.  "The sound of wind rushing around the plane is awing, blood-rushing, soothing, clearing, empowering, pulsing, privilege."

And now, on with the blog post....

The conversation at coffee break this morning ranged through politics, Cessna's profit and delivery woes, and eventually wandered towards aircraft landing speeds.  Sitting next to me was a seasoned Cessna 182/185 glider towplane pilot, and he mused how he had to keep his approach speed up on final, so that he could execute a successful flare into our grass strip.

We talked about how the Belite would do:  was I able to execute landings with the engine at idle?

Why yes, I thought I could land with the powerplant at idle.

Why not give it a try right then?

It so happened that I had our gorgeous 'Harley' orange and black Belite 254 ready for flight; we'd recently completed some upgrades to it, and it was sitting, begging to be flown.  I had test flown it earlier in the day, and I knew that it was ready to fly some more.  Did I say it's gorgeous?  Did I mention that it flies beautifully?


Why not?  Let's do this.  I hopped in, hit the electric starter, and the single cylinder CRE MZ-34 soon came to life.  (Nothing beats an electric starter on an airplane.)

After a brief warmup, I took off into the light south breeze, climbing at about 200 fpm.  (Amazing.  I weigh 200+; the engine is just a miserly little 28hp 'single lung', the prop isn't quite optimum... and yet the performance is great.)  I swung the obedient airplane around the pattern, turned base to final, and retarded the throttle to idle.  With the engine at idle, the plane easily floated over the runway, and I landed without any difficulty whatsoever.  After touching down, I hit the power, went around, and did it again and again.  The Belite lands effortlessly with the engine at idle.  There are zero issues with flare authority, even with the engine at idle.

At this point, you're probably wondering why I would call that a "Deadstick Landing".  Well, I wouldn't.  It wasn't a deadstick landing.  But I had a sly thought....   why not try a true deadstick landing? 

And so the next time I came around and turned final, I verified to myself that the runway was assured.  And I reached over and turned off the ignition.  The engine went from idle to off... and the windmilling prop stopped.  I was floating over the runway a moment later, and flared to a beautiful, light landing with no noise other than the wind over the wings and the roll of the wheels.

I told Gene to grab the camera.  I wanted to do that again!

I fired the engine back up, took off, and did a couple more true deadstick landings, with Gene recording the sequence.  There's some great pics!  Note the stopped position of the prop in each photo...

Here's some final comments.

1)  This plane is for sale!
2)  The cowling was not installed.
3)  The sound of wind rushing around the plane is awing, blood-rushing, soothing, clearing, empowering, pulsing, privilege.

Wednesday, October 20, 2010

Shortly after liftoff, the plane stalled, and then glanced hard into the runway...

Let's all learn from this: a Belite trike had a landing accident yesterday. 

My first thought after it occurred was that I would not take pictures; nor would I blog.  That was an expected first reaction; but incorrect.  I saw it happen; I can still see the whole sequence of events like a motion picture, in my mind.  With permission of the customer pilot, I am now blogging on what happened.

No one was hurt; and the plane was not badly damaged.  And I'm weirdly pleased with how the nosewheel took the blow and then failed in a manner which protected the pilot and the remainder of the airframe.

This particular airplane was equipped with the very strong Compact Radial Engine MZ-201.  I have flown this particular plane many times; we'd sold it and upgraded several features of the plane, including the engine.  We'd also added an inexpensive Second Chantz ballistic chute.

A transitioning pilot was practicing a takeoff roll in the bright yellow Belite.  Although this particular roll was to achieve a height of no more than about 6 inches; it didn't work out that way.  The pilot had been practicing taxiing and had demonstrated proficiency in low and high speed taxiing -- it was time to focus on the transitional takeoff attitude.   

I observed the plane rotate; the pilot quickly leveled the wings.  But by then, the plane was already quite a few feet off the ground and climbing...

In order to cancel the climb, the transitioning pilot cut power, and then the plane angled back towards the ground at a descent angle of perhaps 7 or 8 degrees.  This was probably an inadvertent departure stall.  The plane struck the runway very hard on the nosewheel, which folded under the airplane.  The plane skidded to a stop, briefly tipped sidewise and up onto the left wing, then settled back to the ground.  The main gear were still intact.  It was as if the plane was kneeling forward on its broken nosewheel.

By the time I had made it over to the plane, my customer friend had climbed out of the plane.  He was absolutely fine:  not a scratch, not a bruise.  He was even in amazingly good spirits, all things considered.

We rolled the plane back to the hangar. 

Here's an inventory of the damage:

Carbon Fiber firewall:  undamaged
Left Wing front spar (it hit the ground):  undamaged  (the spars are open and we can easily inspect on inside)
Engine:  undamaged (sheared blades and PSRU provide really good protection to engine)
Propeller blades:  destroyed
Propeller hub:  undamaged
Nosewheel landing gear:  folded under and destroyed
Nosewheel aluminum / delrin assembly and wheel:  no damage whatsoever, even after scraping along ground, but jammed against muffler
Left wing carbon fiber spar, which struck ground:  absolutely no damage
Left / Right nosewheel landing gear braces:  folded under, destroyed
Fuselage front cross member:  1/2 inch bend
Instrument panel bottom cross member (receives nose wheel landing gear strut)  1/4 inch bend

Here's a closeup of the bottom damage:

Nosewheel Destroyed on Belite Trike

 Here's the same thing, after removal of the nosewheel.  This clearly shows how the nosewheel strut has absorbed the blow, along with the nosewheel cross brace struts:

Bent nosewheel strut on Belite, with wheel removed
Look at the above picture very closely, one more time.  You can see the following:

a) bent nosewheel strut
b) bent cross braces
c) very slight bend in fuselage cross brace member (pushed back about 1/2 inch)

Just to make it crystal clear, here's a photo which shows the fuselage cross brace member:

Here's the basic process to repair the airplane:

1. Unbolt the nosewheel strut from the plane.  It has a bolt in the fuselage cross brace member (bolt hole visible in above pic) and below the instrument panel (not pictured).  Then remove.

2.  Remove fabric from front bottom of airplane.

3.  Cut out bent cross tube.

4.  Cut and weld in replacement section and nosewheel strut receiver.  Use doublers as necessary.

5.  Repair fabric.

6.  Insert new landing gear strut and cross braces.

7.  Replace propeller blades.
8.  Inspect & fly.

How did the nosewheel strut perform under this failure condition? 
Everything worked as planned. 

a) The landing gear did not 'jam' up and into the cabin.  Both the lower fuselage cross member and the top receiver cross member exhibited backwards force, but very little bending.

b)  The landing gear did fold underneath and backwards.   In fact, a careful inspection of the nosewheel strut shows that it had gross bending failure at two places, and a minor bend at a third place.  These bends each absorbed substantial energy from the impact, shielding the pilot.

c)  After the landing gear folded under the plane, the plane then skidded along the ground.  The plane did not flip over.

d)  The main landing gear were not damaged or affected.

e)  The 4130 ChromAloy fuselage provided 100% protection to the pilot.  (The 3 point safety harness was an essential piece of his protection.  His torso could not roll forward.)

f)  The damage is easy to repair.  We already had replacement parts in stock.

This happened yesterday.  With the exception of the propeller replacement, the bird should be ready to fly again tomorrow.

Sunday, October 10, 2010

Wichita's Aircraft Industry: Time for Reinvention?

In today's Wichita Eagle (Sunday, 10/10/10), a letter to the editor, from me:

Sedgwick Country Commissioner Gwen Welshimer presented a strong case for reinvention of Wichita's aviation core at last week's commission meeting.

In a presentation designed to help Wichita understand that it remains at a tipping point for its aviation future, she articulated the need to pay attention to developments in aviation — specifically in the light sport and ultralight niches — so that Wichita may continue to call itself the "Air Capital of the World" for decades to come.

It is disheartening that appropriate investments in the grassroots of our aviation industry were not made years ago. Instead, innovative small aircraft designs have been announced in many other cities and from many other countries. (Europe has become a hot spot for aviation technology development.) Some of these innovations are producing orders along with jobs.

All of these developments are in harmony with what this city already builds and sells — the world's greatest general aviation airplanes, jets and airliner components. But the smaller, less-expensive products rebound first from difficult economic times, and they are lacking from our community's collective product offerings (with the exception of Cessna Aircraft's Skycatcher and Belite Aircraft's "254" and derivatives).

Welshimer should find support from our community for the development of programs that will enhance the ability of our entrepreneurial private sector to create new aviation products and resulting jobs. Will she?

Belite Aircraft

Read more:

Friday, October 8, 2010

Wichita Eagle quotes James on aviation incubator idea

The Wichita Eagle wrote an article about Gwen Welshimer's propsoal for an aviation technology incubator in Wichita, KS.  A couple of her ideas were pretty far out there, but most were based on realistic aviation products that are happening now. 

The Eagle's article was slanted towards the stuff that was 'far out', and slanted in a negative way. 

But they finished the article with a very nice quote from me.

You can read the Eagle's article here.

Wednesday, October 6, 2010

Technology and Aviation Leadership in Wichita, KS?

Today, at the invitation of Sedgwick County Commissioner Gwen Welshimer, I briefly presented my viewpoint of the difficulties of starting an aviation business in Wichita, KS, Air Capital of the World:

 -- Difficulty raising capital or debt financing
 -- Lack of vision on the part of government for supporting entrepreneurial aviation and technology business in a meaningful way.

My comments followed a presentation by Commissioner Welshimer, in which she made a case in which Sedgwick County should take its rightful position as incubator for aviation technology.

She's absolutely correct.

You can see her presentation, and my response to the Commission, in this eVideo

Two of the three local TV stations interviewed me; fantastic interviews; and they each took great video of the Belite flying out at our base airport.  You can see the videos and their stories here:

Channel 12 - KWCH Story on Personal Planes and Belite

Channel 10 - KAKE Story:  Could Innovation keep Wichita the Air Capital?

Wichita is in danger of losing its status as Air Capital of the World. 

Motor Oil mixed with Grinding Abrasive, Challis, Cabin Creek Airstrip, a Cessna 172, a Fuel Leak, and a Friend

Motor Oil mixed with Grinding Abrasive, Challis, Cabin Creek Airstrip, a Cessna 172, a Fuel Leak, and a Friend

by James Wiebe

I had developed a habit of flying into Idaho, nearly every summer, to go camping in the Wilderness. 

This trip would follow in the annual tradition.  I was flying with Mike Andrews, my pastor friend from Colorado, and we were headed to Cabin Creek airstrip, near Big Creek, home of world class cutthroat trout and world class cabin.  Cabin Creek is a gnarly little airstrip, and curls up the side of the hill like a well used jeep track, hidden in a mountain valley.  It curves, it climbs, and it ends abruptly.

But I'm getting ahead of myself.

Challis, Idaho is a very important little town to me.  It's where I learned the ins and outs of mountain flying, way back in 1996, at a mountain flying school.  It's close to the backcountry, where wilderness, rivers, wildlife, and airstrips intertwine, but no roads:  there are no roads in the wilderness.

Challis has a diner or two, a couple of motels, a great airport, 2 or 3 FBOs, a backcountry air taxi service (or two), an outdoor store and some houses.  Maybe a gas station. 

Challis is an excellent spot to spend a last night, before hopping into the wilderness.

The weather was perfect:  blue skies, reasonable winds.
The airplane was packed with all our camping equipment.   Backpacks, flyrods, water bottles, food.
The airplane itself:  my old friend, a 'Superhawk' Cessna 172:  180hp in a light airframe:  great performance, great useful load.  A superb backcountry bird.
The friendship:  Mike and I are tight.
The destination:  as good as it gets:  fishing, camping, wilderness, isolation, friendship, a fire under a sky as black as coal; stories between friends. 

Mike and I were nearly ready to depart.  I walked into the FBO, and requested a quart of oil before we departed.

I unscrewed the lid of the oil container.  I found it odd that the lid snap ring was already loose.  I was too stupid to make this stop me from what I did next.

I started to pour the quart of oil into the engine.  Oil came out; also a white milky substance in the oil.  I watched the white milky substance run down the funnel and into the engine.  I stopped pouring the oil into the engine.  I walked back to the FBO, and told them what I had just seen entering my engine from the oil bottle they had just sold me.

The FBO Man immediately knew that he had committed a great sin.  He had sold me a bottle of motor oil, except that he had given me a used bottle of grinding oil, filled with grit from an abrasive wheel.  He confessed his sin to me.



The weather was no longer perfect:  blue skies, reasonable winds and an airplane with an engine filled with grit.
The airplane was packed with all our camping equipment.   Backpacks, flyrods, water bottles, food, and engine oil contamined with grit.
The airplane itself:  my old friend, a 'Superhawk' Cessna 172:  180hp in a light airframe:  great performance, great useful load.  A superb backcountry bird, especially when the engine does not have grinding grit in it.
The friendship:  Mike and I are tight.  That is not affected by grit in the engine oil.
The destination:  as good as it gets:  fishing, camping, wilderness, isolation, friendship, a fire under a sky as black as coal; stories between friends, and all of it hopelessly unattainable, due to the damn grit in the engine. 
The FBO Man said:  "I will thorougly flush your engine and refill it with oil; I will fly you and your friend into the wilderness, I will make this right."

FBO Man began his repairs.

Mike getting in the Superhawk; cowling removed and engine flush under way.

Later in the day, he flew us into the backcountry.  We landed at Cabin Creek airstrip later that afternoon. 

Looking uphill at Cabin Creek; watching a departing aircraft; the black strips are rubber water diversion drain strips.

FBO Man dropped us off, and Mike and I started the hike from the airstrip down to the river.

We ended up at an ideal camping spot, not more than 20 yards from Big Creek.  Our tent was pitched under some trees.

Over the next few days, Mike and I entered into an easy routine of fishing up or down the river, using a mostly grasshopper imitations and other high floating dry flies.  Fishing was easy; cutthroats kept coming to the fly. 

Big Creek is an extraordinary river.  Upstream, it falls over boulders and descends so that pools and bends are hard to find. 

Downstream, it gathers itself in a sharp run that might fish well.  Inbetween, it wanders through a series of cuts and bends that kiss the opposite bank.  Tall grasses flop over the edge of the river.  Cutthroats hide under the tall grass edges. 

A beautiful hole is in the mid-valley.  Far deeper than most of the river, it's occupied by some trout that love depths and disappearing.

Cabin Creek (of which the airstrip is named after) flows into Big Creek.  Cabin Creek is a tiny trickle of water, and surprisingly, it holds big trout as well.

Now it's night time.
The sky is coal black.
Mike and I settle into our sleeping bags.
Mike asks questions about my spiritual condition.  He helps me focus on my faith in Christ.

The weather has been perfect:  blue skies, reasonable winds.
The airplane will once again be packed with all our camping equipment.   Backpacks, flyrods, water bottles, food.  Except we've eaten the food; not much is left.
The airplane itself:  my old friend, a 'Superhawk' Cessna 172:  180hp in a light airframe:  great performance, great useful load.  A superb backcountry bird.
The friendship:  Mike and I are tight.  
The destination was as good as it gets:  fishing, camping, wilderness, isolation, friendship, a fire under a sky as black as coal; stories between friends. 
It's time to go home.

FBO Man has flown my Cessna Skyhawk into the airstrip, and it is waiting for us.  (I will not pen the logistics of how all that happened, or how we communicated with the outside world.  It's not worth it, and besides, this story is a little more mysterious if you don't know all the details, such as how I had a satellite phone and used it as necessary.)

I start the engine, and taxi it from the low end of the airstrip up to the high end, so we can turn around and takeoff downhill, into the valley.  It's impossible to take off uphill, just look at the first picture in this blog.  Uphill takeoffs are impossible!

At the top end of the airstrip, I turn the engine off.  In hindsight, I don't know why.  I guess I wasn't ready to take off.  I got out of the airplane, and looked at the engine compartment.  While inspecting the nose wheel, I notice that it has a drip of liquid running down it continuously.  If I had taken off, the gas would have run out the front of the airplane, and the engine would have soon quit.

Gasoline is running down the nose wheel.!! This was the second breakdown of the trip.  This time, I was in the wilderness.

FBO Man flew back into the airstrip, in his Cessna 206.  He brought tools and parts with him.  He proceeded to disassemble the gascolator on the airplane and replace a gasket.  The fuel leak had absolutely nothing to do with the oil flush and replacement he'd done with the airplane earlier in the week.

So he billed me for this wilderness gascolator gasket repair:

Flying into the wilderness:  $280 roundtrip from Challis in his Cessna 206  (a bargain).
His time:  2 hours;  $120 total. 
One 'O' Ring gasket:  $1.

Total bill:  about $400.

Mike and I headed home.

Monday, October 4, 2010

Powerfin Propeller: Recommended! (But choose length and adjust pitch wisely)

I've been doing some testing on a Powerfin propeller on our Superlite.  I've come to the conclusion that if properly selected, Powerfin's composite propeller provides a superior alternative to the wooden propellers which we've been using on our aircraft.  (Albeit at a higher cost.  Most good things cost more.)

Last year, I flew quite a bit with a 3 blade Powerfin propeller.  I was not happy with the performance.  In hindsight, the issue was our selection of a short 3 blade prop -- we should have tried a two blade.

And so, I had switched to inexpensive 2 blade wood propellers.  They were a good, economical solution providing reasonable performance.  Their downside is maintenance (their leading edge will erode, especially in heavy grass fields) and inability to adjust pitch.

Recently, I was contacted by Powerfin to consider the usage of their propeller with our aircraft.  We received a brand new "B" series propeller, and we bolted it onto our Hirth 50HP engine.

I wanted to know the answers to these questions:

a)  Would this propeller provide any increase in efficiency over our most ideal wooden propeller?

b)  Would this propeller allow for easier power tuning for Part 103 users?

c)  Would it look cool?

The answer to all 3 questions is yes.  Here's more of the story about efficiency and prop re-pitching:

I've done power consumption testing on the Hirth, and reported on the results in this blog a couple of months ago.  The gas consumption was 3.4 gallons per hour.  The U.S. distributor of Hirth engines suggested I might be able to improve on this fuel consumption figure; I was a little skeptical.  But the Powerfin propeller appears to have proven him correct.

To test the configuration, we selected a prop length of 65 inches, in the "B" series ground adjustable propeller from Powerfin.  This is the longest propeller I've ever thrown on our aircraft.  I thought the extra length would help with efficiency.   I then selected an initial propeller pitch using an online tool I've found which helps interpolate diameter, pitch, RPM, atmospheric conditions, and engine power.  You can find this propeller tool here.  In order to really make it work, you have to convert diameter and pitch to an angle setting for the propeller pitch.  I use this tool to perform that calculation, just put in circumference and pitch into the calculator, and it delivers an angular setting.  (For a 65 inch prop, the circumference is 204.2 inches -- you know how to do that, right?!)  [diameter * 3.142 = circumference]. 

After selecting an angle of 7 degrees, we used a prop protractor to set the propeller 'bite' or pitch, bolted all the bolts to the recommended torque values, and it was time to runup and test power.

As it turned, a quick runup and takeoff showed me that this pitch angle (7 degrees) was too much of a bite, and the engine would not rev up to full power.  In fact, not even close.  However, it was sufficient to get off the ground and allowed me to enjoy flying a grossly underpowered utralight aircraft, but not for very long.  (I landed.)

So the pitch was reset to 6 degrees, and I took another test flight.  This time, the engine was still not able to develop full power, but that's OK -- it climbed great, and was already exceeding the FAR Part 103 cruise speed limit by a wide margin.  (Cruising at 61 knots, 6 knots too fast, this is about 70mph.  If I cut the pitch angle back to about 5.5 degrees, the engine would develop higher RPM and full power, and the Belite Superlite would go EVEN FASTER (probably around 75mph cruise), but that's not my objective.  (However, it may be your objective, if you are building a Belite as an experimental N-Numbered homebuilt aircraft.)

I want to be able to cruise at exactly 55 knots -- which is 62mph, which is the FAR Part 103 cruise speed limit.  So I'll soon reset the pitch to about 6 1/2 degrees.  This should be just the right amount of power.  In other words, the adjustable pitch prop is an excellent way to fine tune a big horsepower engine to be FAR Part 103 legal.

I continued my testing of the Powerfin prop.  I started with a full tank of gas, and I cruised for an hour at exactly 62 mph, with a few takeoffs and landings mixed in.  I then landed and checked fuel consumption with a measured dip stick (I'd also been tracking fuel consumption in flight using our fairly amazing Belite fuel gauge):

Belite Fuel Gauge -- works great -- please buy one.
At the end of the flight, I'd used 3.15 gallons, and I had 1.85 gallons remaining.  Therefore, total time to fuel exhaustion is about 1 hour and 35 minutes -- a substantial improvement over the wooden prop I'd been using.

When using the Hirth 50HP engine and the Powerfin prop, this calculates to a range of a Belite Superlite, in FAR Part 103 legal mode, of 98 miles.

And I do like the way the Powerfin looks!

Here's some things to keep in mind:

a) The larger diameter is definitely a good thing.  However, proper technique calls for 3 point landings and careful takeoffs to avoid grass rash on the prop.  If you want a little shorter prop, I wouldn't go with anything less than a 60 inch diameter on a Belite.

b) As I mentioned earlier, good things come at a price.  These composite props aren't cheap -- but they are worth it if you want the most adjustable option combined with the most efficiency.

c) Also, they are little heavier than wooden props.

d)  I will be adding this prop to our price list.

-- James