Vortex Generators and Ultralight Aircraft

Vortex Generators.

IF YOU ARE READING THIS ARTICLE, YOU MAY ALSO BE INTERESTED IN THESE OTHER ARTICLES ON VG's and STALL SPEEDS:


http://jameswiebe.blogspot.com/2010/09/even-more-info-on-stall-speed-vortex.html

http://jameswiebe.blogspot.com/2010/06/belite-coefficient-of-lift-and-stalling.html

Vortex generators are mounted on the top side of wings, and are designed to create small vortices as air passes over the wing.

As a result of these small vortices, vortex generators (Let's call them VGs, OK?)  are responsible for doing some pretty amazing things.  Concerning VGs, Wikipedia says the following:


"Vortex generators are likely to be found on the external surfaces of vehicles where flow separation is a potential problem because vortex generators delay flow separation. ^[3] On aircraft they are installed on the front third of a wing in order to maintain steady airflow over the control surfaces at the rear of the wing.^[2]boundary layer, and run in spanwise lines near the thickest part of the wing.^[1] They can be seen on the wings and vertical tails of many airliners. Vortex generators are positioned in such a way that they have an angle of attack with respect to the local airflow.^[1] They are typically rectangular or triangular, about 80% as tall as the boundary layer, and run in spanwise lines near the thickest part of the wing.^[1] They can be seen on the wings and vertical tails of many airliners. Vortex generators are positioned in such a way that they have an angle of attack with respect to the local airflow.^[1]

A vortex generator creates a tip vortex which draws energetic, rapidly-moving air from outside the slow-moving boundary layer into contact with the aircraft skin. The boundary layer normally thickens as it moves along the aircraft surface, reducing the effectiveness of trailing-edge control surfaces; vortex generators can be used to remedy this problem, among others, by "re-energizing the boundary layer".^[1][2]

The use of VGs on FAR Part 103 ultralight aircraft has been debated at least a little; I've decided to get into the debate by actually giving them a try on our Dragon Superlite.  A couple of days ago, I temporarily attached a set of VGs to the Superlite and then flew the plane.  Here's what they look like:

How did they work out?  I don't really know.  The wind was gusty aloft, so it was difficult to check out stall speed, landing characteristics, and I've reached no conclusions so far.  But I've decided to leave them on the Superlite as it heads to Oshkosh.  Come on by our North display area and take a look.

Amy Arrow and Never Again

Oshkosh preparations have been running us 7/24.  We've been preparing 3 ships for Oshkosh Airventure; on top of that we just completed a customer delivery and we have another which we won't get done before Osh.  (But we wanted to.)  And on top of all that is our 'secret ops' which are preparing some major whammy to talk about at Osh.

But never mind that.  Time to write a blog post...

Please back up about 15 years in my life....  to a memory from my past.

I was heading to Denver, Colorado to attend a "Promise Keeper" event.  I had arranged to rent a retractable Piper Arrow, which boasted a 180HP engine, good range, and a useful load of about 850 pounds.  The owner of the airplane affectionately called her 'Amy Arrow'.

It was hot in the summertime; we landed at Centennial airport without issues.  The Promise Keepers event was soon over, and we headed back to Centennial for the flight home. I had myself and 2 friends on board, (or, as I liked to say when I filed a flight plan, 3 souls on board).  

I had filled the tanks for the flight home.  I had also carefully reviewed the flight manual:  the flight manual called for 25 degrees of flaps in order to produce a short ground roll.  I dialed in 25 degrees, per the manual.  (Very stupid... as you shall soon see.)  Our plane was exactly at gross weight.  Density altitude was somewhere around 8500+ feet.  That shouldn't be a problem with an airplane that had a service ceiling well over 13,000 feet...   right?!

We were cleared for takeoff at Centennial.

I advanced the throttle, and Amy Arrow started to move down the runway.  Slowly.

Somewhere around 3 or 4 thousand feet down the runway, I started to pull back on the elevator.  Amy dutifully rose about 8 feet above the ground.

And stayed there.  5000 feet of runway remaining.

And stayed there.  4000 feet of runway remaining.

And stayed there.  3000 feet of runway remaining.

And stayed there.  2000 feet of runway remaining.

And stayed there.  Still 8 feet off the ground, 1000 feet of runway remaining.

I refused to set it back down and abort the takeoff.  Why?  More youthful piloting stupidity.

I saw a ridgeline off in the distance, straight ahead.  That was a problem.  I would hit it.

I saw a descending valley off to the left.  If I turned that way, I would have terrain descend, thus improving my relative altitude to the ground.

I slightly turned to the left.

I realized I was hovering over the ground... the plane would not climb.  I had two opportunities to reduce drag:  Get the gear up.  Reduce flaps.  I also realized that if I rapidly retracted flaps, the plane would immediately settle to the ground.  First things first... I retracted the landing gear.

Then, I grabbed the manual flap handle, and   s l o w l y  went from 25 degrees, to 20, then to 15, then to 10 degrees of flaps, then to five, then to zero.   The plane seemed to stop mushing over the ground.

We flew over a golf course.  Since the terrain was descending, and we were now probably climbing at 50 feet per minute, we had perhaps 150 feet of altitude over the course.  Some golfers looked up at this strange sight of an airplane, so close to the ground, passing over to them.

And then I realized that the plane had perhaps 250 feet of the ground, and that positive climb was definitely occurring.  We would be okay.

And then I realized something else was occuring:  the tower at Centennial was talking to me.  I hadn't heard them, because the crisis had shut down that part of the brain that listens to outside voices.

"are you OK....   are you OK...   are you OK..."  I could also hear our N number, recited over and over.

"Yes, I'm OK".

They couldn't see me:  my plane had turned left and disappeared below their horizon.

I soon cancelled flight following and headed home for Wichita.  I kept wondering what my passengers were thinking:  had I just nearly killed them?

Here is my list of stupidities:

  A)  Dialing in 25 degrees of flaps is great for reducing ground roll, but does not improve Vy.  In fact, it has the opposite effect.  You can't climb with 25 degrees of flaps in a 180HP Piper Arrow.

  B)  Density altitude is a killer.  A non-turboed Arrow is a horrible climber in high DAs.

  C)  Flying at gross weight in high DAs is also a killer.

  D)  Lean the engine!  

  E)  And most importantly:  aborting the takeoff.  I had multiple opportunities to abort and I did not do so.

As Flying magazine says, Never Again.

 

Belite Trike test flight

Here's a series of photos of a FAR Part 103 Ultralight Aircraft:  the Belite Trike, in test flight, preparing for customer delivery.  There's no cowl on this plane (yet) but the olive drab paint scheme looks sharp, and will be great as a base of a military paint scheme.

The plane flew absolutely wonderfully.  Performance exceeded my expectations with a 28HP Hirth engine.

Plane is ready for delivery and should be on the truck next week, heading to a customer out of state.

Wichita Machinists, Disc Brakes, and Part 103 Ultralight Aircraft

Wichita, KS is the home of Belite Aircraft and also the Aircraft Capital of the World!

As home to a majority of general aviation aircraft (EG:  Cessna, Beechcraft/Hawker, Bombardier/Learjet, also Spirit Aerosystems and Boeing Military) with notable exceptions of Cirrus and Piper, Wichita has a diverse manufacturing community.   In particular, there are hundreds of small, medium, and large businesses which provide components to the major aviation companies.

Many (but not all) of those companies have been hurt badly by the aviation slowdown of the last couple of years.

This has been an opportunity for Belite:  we've been able to find a machine shop or two who are capable of providing us with very high quality machined parts for our Belite Part 103 ultralight aircraft.

And tonight, I provide just one example:  our new disc brakes, which we are installing on our ready to fly and kit aircraft.  These disc brakes are composed of three major components:  a machined 'tripod' standoff, which works in conjunction with a solid steel 4130 chromalloy axle to attach to the brake rotor and to the wheel; a brake attachment plate, and, of course, a disc brake caliper/rotor assembly, which comes directly from the mountain bike industry as an OEM component.  It works great for our lightweight aircraft.

Here's what the assembled brake looks like (the brake cable is not attached in this photo) (also note the steel spring suspension):

It's a very tight, neat looking arrangement.

The aluminum components are machined from solid billet: 6061T-6, which is a common aircraft alloy.

Let's take a look at each individual component.  Here's the standoff 'tripod':

And here's two more views of the same part:

This 'tripod is used to fix the brake caliper to the wheel.  It's designed to work with our 5 inch wheels, which are now the standard wheel on every Belite aircraft.

Another component is the brake attachment plate.  It's a simple part, and is very strong.  Here it is:

To make all of this work, we do need a disc brake rotor and caliper.  As I mentioned previously, our Part 103 ultralight aircraft are well matched to use a brake from Avid.  Here's the brake:

So let's stack all these parts up and see what it looks like.  You can see the 'Tripod' below the brake rotor:

And let's now put the attachment plate on top:

Obviously a few nuts, bolts, axles, and cables missing.  But hopefully, you get the idea.

Here's one more look at how it ends up on the aircraft landing gear:

Side note:  Look at that nice big fat 5.00 x 5 tire!

We sell these for $350 as a kit and $400 installed on our flyaway airplanes.  The kit includes left and right sides.  (pricing always subject to change without warning.)

You can find them on our Ready To Fly spreadsheet, and also on our Price Your Own Kit spreadsheet.

My thanks to my able assistant Gene Stratton for shooting these pics.

A great trailer for hauling an ultralight aircraft

How do you trailer an ultralight airplane?

A common question concerns trailering our Belite ultralight aircraft.  For long distances, nothing beats a covered trailer.  But for short distances, a boat trailer works great for hauling the aircraft between your home and the airstrip.  You just have to do a little work to make it work perfectly.

My friend, Terry Alley, bought a boat trailer and modified it to haul his Kitfox Lite around.  I recently borrowed his trailer to haul a Superlite from our hangar, over to my Church for a car show.  (And that's another story, how our airplane ended up being the only airplane at a car show.)

Here's a pic which shows the Superlite on the trailer. Note the trailering bar which are attached to the leading edge of the wing, down to the strut attachment point.  (This provides rigidity to the wing, so that it is not damaged while trailering.)  Also note how the ramps have been set at just the correct width to allow the plane to roll backwards and onto the trailer:

Here's a pic of the airplane on the trailer from the side.  Note that the trailer is exactly the correct length, so that the tailwheel is by the ratchet lever:

Here's pic of the aircraft from the front of trailer, looking back.  You can see a gust lock on the elevator/stabilizer on the right side:

The airplane is just a little long for this trailer, so the tailwheel springs have been disconnected, and the tailwheel twisted 180 degrees backwards.  The tailwheel fits into the steel channel which is part of the original trailer.  Note the ratchet drum (which isn't used for anything anymore) and also note the center 'V' channel which Terry mounted on the trailer.  This is for the tailwheel to 'roll up' the trailer as the aircraft is backed onto it.

After the airplane is loaded, the wheel ramps rotate up and are bungeed in place.  This locks the wheels and the aircraft onto the trailer.  Also note the wooden plank across the rear of the trailer.  This was put on the trailer so the aircraft tires would have a solid place to rest.

You can't see it here, but some straps are used on the other side of the wheel to lock the landing gear strut in place, so it can't roll at all.  I also use some extra bungees around the landing gear to the boat trailer, as good redundancy.

In this pic, you can see the red nylon straps.  You can also see our awesome steel spring landing gear on the Belite:

Don't forget to tie the tailwheel to the front of the trailer.

Also, don't forget to install solid gust locks on the rudder and the elevator.

And that's really all there is to it.  Trailering a FAR part 103 ultralight is easy; so is trailering any small experimental aircraft.  I hope this gives you some good ideas on how to make a great, inexpensive trailer for hauling your aircraft around town and out to the airstrip.

Sold the Kitfox Lite, Again

That pesky Kitfox Lite which I had for sale has been sold for a second time.  After the first buyer backed out, another emerged a few days later. 

The new buyer has instructed us to perform some upgrades on it before it is delivered.  Bigger tires, bigger wheels, better spring suspension, different engine.  All fun stuff!

How to make a Carbon Fiber elevator which weighs less than 3 pounds!

I am planning to give a forum at OSHKOSH on how to make a Carbon Fiber elevator.  PLEASE PLAN TO ATTEND!  Thanks.

The Carbon Fiber elevator which is depicted here WEIGHS LESS THAN 3 POUNDS!  And it is stronger than steel.

Carbon Fiber offers benefits which make it vastly superior to 4130 chromalloy steel in many applications.  Careful design is required, though, in order to take advantage of Carbon Fiber's incredible strength and stiffness.  Belite's Carbon Fiber elevator upgrade swap is an available upgrade for any Belite (or Kitfox Lite replacement aftermarket) which will provide a lighter part with far higher strength and better aerodynamics.  This part is available in kit form for a price of $350 over the regular elevator.  (You can find it on our kit pricing spreadsheet here as line item #55.  Remember, this is an upgrade price over the steel elevator (which is separately priced at $399.95).  A straight purchase of this Carbon Fiber elevator kit is $399.95 + $350 = $749.95)

Our Carbon Fiber elevator is a direct replacement for the steel part.  It is made from several basic materials:

Carbon Fiber fabric wound tubing (for leading edge / torque spar)
Carbon Fiber extruded tubing (for trailing edge)
Steel horizontal stabilizer connect hardware (qty 2 -- connects to hinge points on horizontal stabilizer)
Central Steel section (connects to hinge point and to elevator push/pull tube)
Carbon Fiber ribs in various laminations from 3 to 6 layers of carbon fiber 3K cloth, over balsa core
3M 2216 industrial epoxy (amazing stuff)
Laminating epoxy
Dacron Fabric

Jumping to the finished part, here is what it looks like:

And here is how to make it:

1)  Ensure Carbon Fiber spar tube is exactly 92 inches long.  Cut with fine tooth saw to length.

2)  Debur, clean and slide the center steel assembly over the spar tube.  Epoxy in place with 2216 glue.

3)  Debur, clean and slide each hinge point over the tube.  Do not epoxy. 

4)  Cut each rib section using a band saw and supplied rib outline.  Cut front circle to match spar tube.  Leave rear portion extra long, excess length will be trimmed.  Carefully cut angle cuts on center ribs; also cut reinforcement segments. 

5)  Cut wingtip ribs and center ribs to exact length. 

6)  Cut trailing edges to length; you may leave them slightly long.

7)  Glue wingtip ribs and center ribs in place to main spar and trailing edges using 2216 glue.  At this point, you have a complete outline of the elevator.  Allow to fully cure (24 hours) before proceeding.  It is helpful to wrap around carbon fiber tube and ribs with masking tape.  This will force glue to exact shape and is easy to pull masking tape off after curing.

8)  It is now easy to continue fitting each rib to exact length requirement.

9)  Glue all ribs in place using 2216 glue.  Glue remaining hinge points in place.  Allow to fully cure (24 hours) before proceeding.

10)  Now all ribs are in place.  Sand excess 2216 off.  DO NOT sand into any Carbon Fiber.

11)  Reinforce all joints using carbon fiber cloth and conventional laminating epoxy.  This is easily done by laying the carbon fiber strip over the edge, with the elevator vertical, and painting on the epoxy.  It is helpful to do the leading edge, allow to cure, then flip the elevator and do the trailing edge.

12)  Trim excess cloth using either a dremel or a sharp razor blade.  If you use a razor blade, it is helpful to do it prior to full cure of the epoxy.

13)  Sand all Carbon Fiber cloth.  Remove every single sharp point.

14)  Cover using Stewart Systems glue and dacron fabric.

Here's the advantages:

a)  thicker profile allows aerodynamic shape
b)  lower weight, of course
c)  stronger
d)  impervious to rusting
e)  It's just plane cool!  Or is it plain cool?!

Here's some more detail pics.  Our kit includes plans and more assembly info.....

Art Belite

Let me know what you think of Art Belite:

Belite Kit Pricing

We've posted a Belite Kit Pricing spreadsheet online for our FAR Part 103 ultralights, click HERE to see it.  This spreadsheet lets you manipulate any or all of the options to make the kit exactly the way you want it.

You'll notice that all the base kit items are detailed out, and you'll see the pricing value of each line item.  Have a look, and if you're interested in a kit or have any question, send us an email or give us a call.

Line items 1 through 34 are standard in the base kit, while line items 35 through 60 are options.

If you are interested in our Ready To Fly (RTF) aircraft pricing, that post may be found here.

Moonlight is bright; sunlight is perfect

 (c) 2010 James Wiebe.  Reproduction not allowed without written permission of  the author.

1.  Moonglow

I am standing outside the tent.   I can hear the Middle Fork of the Salmon river flowing not more than 30 feet from where our tent is pitched.  I can feel the stillness of the air.  The temperature is perfect -- cool, not cold, not warm, not uncomfortable.  Cool.  Just cool.  It is exactly as it should be in the night.

The temperature is perfect, the night air is perfect, the sound of the river is perfect, yet there is something creating more majesty than any of these minor senses.

Belite Landing & Levitation

A quick photo essay on a landing sequence to a perfect 3 point levitation.  Here's ace pilot Scott Severen, coming in for a landing in Belite's FAR Part 103 Ultralight aircraft: the Superlite.



And here's the Levitation:

How to price a Ready To Fly Belite airplane

One of the challenges of running a small aircraft business (double entendre intended) is explaining our option list to our customer base.  I made a post a few weeks ago where I provided some spreadsheet excerpts explaining some options. 

Now we've made it simpler - we have a online page which allows you to dynamically select any options you want, and see the resulting price and the resulting aircraft weight.

Every single model we sell is basically the same airframe, modified for performance (which is our Superlite, with a 50HP engine) or for tricycle gear, or for light weight, or for better paint jobs.....  Starting from a baseline configuration (which we call a Belite 254), you can click option buttons to see what your ideal airplane weighs and costs.  Create a Trike; create a Superlite, create a Dragon, create whatever kind of FAR Part 103 Ultralight aircraft suits your fancy.

Give it a try, it's fun!

There's also 'preset' buttons at the top of the pricing page which allows you to click one button and see various model configurations show up in the dynamic pricing / weight spreadsheet.

Give it a try and play with it --- just click here and you'll land on the correct page on our website.

Enjoy! 

James

Belite Ultralight Aircraft Stalling Speed

I've run into some interesting discussion out on the social networks discussing or questioning the ability of the Belite ultralight aircraft design to stall at 24 knots.

A quick analysis of the FAR Part 103 rules, as it relates to ultralight aircraft, specifies five critical technical conditions for the acceptance of an aircraft as meeting part 103:

a) Weight, not to exceed 254 pounds, although there are several exemptions.  (Under certain conditions, weight may be as high as 338 pounds, and still meet Part 103.)

b) Stalling speed, not to exceed 24 knots Calibrated Airspeed. 

c) Cruising speed, not to exceed 55 knots calibrated airspeed.  This translates to a True Airspeed of as high as 74 mph (conditions:  10,000 feet; 0 degrees C, 55KCAS) or even higher.

d)  Fuel capacity not to exceed 5 gallons.  Part 103 incorrectly indicates that this is 30 pounds of gas -- which is simply not true.  It can represent up to 33 pounds of gas.  See this link for an explanation.

e)  Single seat operations.  Not much of a technical consideration; this is easy to verify.  If you wanted to get two people in our airplane, each would have to have a butt with a width of 8 inches.

For these FAR Part 103 rules, it is easy to verify a, c, d and e, and thus ensure that your aircraft is a legal ultralight.  (There have also been discussions of why Belite would use a 50HP engine, thus potentially allowing cruise > 55KCAS -- I'll get to that in another post in the near future.)

Moose Creek, Idaho -- An Ideal Camping Spot

(c) 2010 everything on this blog is copyright James Wiebe, including text and photos.  Reproduction without written permission is prohibited.  High resolution images are available -- contact author for further information.

An Ideal Camping Spot has the following characteristics:

pristine, cold rivers which are clear as gin
trout in those rivers
mountains on all sides
deer, maybe elk
just a few campsites
no roads to get there, just trails and a backcountry airstrip
a USFS cabin, with a friendly forest volunteer
perfect temperatures -- 80's in the daytime, 40's or 50's at night
campfire conversations
at nightime, coal black skies, diamonds set in them
also at nightime, an occasional shooting star
just a few airplanes
just a few pilots and campers
friends, family

Moose Creek is such a place

Tonight's Post is in England

I was invited to write a guest post for an English aircraft blog.  So I wrote one up concerning Carbon Fiber usage in our Belite aircraft.  In particular, I covered details of our upcoming carbon fiber stabilizer.  It's a four pound work of carbon fiber art:  strength and stiffness are off the chart.

But if you want to read about this new development from Belite, you have to make the round trip to England.!

Which is easy to do on the internet:  just click here. and you will be on the GolfHotelWhiskey blog, run by Matthew Stibbe.  He's got some good stuff on his blog!

Here is a high res pic of our carbon fiber horizontal stabilizer.  This same photo is on the blog in England, but this one's a little higher resolution.

As you have noticed, this Belite blog is expanding.  Our increased content is drawing readers just like you.  (Thankyou!) 

Thanks for your interest:  enjoy the reading.

-- James

First Flight, Circa 1970; Cessna Aircraft teaches me to fly; more.

A reminder:  this work is (c) 2010 by James Wiebe.  Reproduction is prohibited.  You may link to this blog or this posting.

Chapter 1:  First Flight

I grew up in Hillsboro, KS -- a town of about 3000 people in Marion County, Kansas.

Having lost my father before my fourth birthday, I have treasured experiences which I was given by other male figures in my youthful years.

I attended Parkview Mennonite Brethren Church in Hillsboro.  There was a man there, by the name of Dave Breese.  He was large man -- not necessarily in girth, but certainly in height, and also certainly in stature within that Church.  He was an 'evangelist', a radio speaker, an author, and -- a pilot.  I remember an odd characteristic of Dave Breese:  he attended our Church, but he was not a member.  Odd.  I don't quite know how to explain it.

As it pertains to flying, I do not remember how the invitation was made, but I do know that one Sunday afternoon, probably when I was 12 years old, he offered to give me a ride in his twin engine airplane.  This was an opportunity nearly on the level with Red Ryder BB guns.  An airplane ride.

I am positive that afternoon was a sunny day with bright white cumulus clouds.  A perfect flying day.

I do remember being in the airplane as he started each engine -- and I remember my anxiety that the engines wouldn't start.  But they did.

In those days, the Hillsboro airport was a grass strip.  In later years, it was paved; it suffered a fatal aircraft accident; (hence it's name, Alfred Schroeder field, honoring one of the dead) and I flew often from it.
 

Ground Handling

Long time readers of the blog are certainly aware of the incident last summer in the Flint Hills, where the right main landing gear axle snapped off after an unfortunate encounter with a pothole in the prairie; resulting in unfortunate (but relatively minor) damage to the maiden ship of the Belite fleet.

I sat on the ground for a period of hours, whilst working on email catchup and generally wondering when help would show up.  (It was hot, I had no water, but I had a cellphone, a Spot, and a good internet connection on my computer.)

That particular aircraft was equipped with solid tie rods on the landing gear.  No bungees, no springs, no nothing, so there was no shock absorber in the landing gear.

Very recently, we've started to offer a solution which improves ground handling over bumps considerably: spring steel landing gear.  Take a look at this pic:

Now this is an improvement.!  The first time I taxiied our aircraft with this landing gear, I felt like I had changed from a 1920's vintage model T to a car with a real suspension and shocks.  All the bumps smoothed out.  Amazing!  Cool!  Fun!  Driving an ultralight on the ground no longer felt like a bumpfest.

Above is a closeup photo of a mud splattered shock absorber spring.  Works like a charm.

We're offering them as optional equipment on our aircraft:  installed:  $200. 

Builders can add them simply by buying a pair of springs, available from MSC, for about $9 apiece.

Would it have made a difference while taxiing in the flint hills?

This product improvement is available on our award winning Belite Superlite ultralight aircraft, or with any of our other Part 103 aircraft.  You can purchase our aircraft as kits or as fully assembled, ready to fly.   See our aircraft at www.beliteaircraft.com, or read more about ultralight aircraft at my blog.

Used Kitfox Lite for Sale! --- SOLD! July 2, 2010

NOTE FROM JAMES:  IF YOU ARE LOOKING FOR AN ULTRALIGHT AIRPLANE, WE HAVE SEVERAL FOR SALE.  GIVE JAMES A CALL 316 393 5477 -- and now the original post continues...

We now interrupt this blog for an important announcement:  Our original Kitfox Lite is now for sale.  Yes, this IS a Kitfox Lite.  I originally bought this as a used airplane a couple of years ago, and it was very helpful to us as we developed our Belite 254.  But we don't need it any longer.

The aircraft in question was temporarily turned into a Belite 254 (through the addition of carbon fiber wings) and was featured on the cover of EAA's Sport Pilot magazine.

We have returned it to its original Kitfox Lite wings, which we saved, and we have basically given the plane a frame off restoration to new condition.