WPA's blog - RC Groups
WPA's blog View Details
Posted by WPA | Mar 03, 2014 @ 04:16 PM | 3,176 Views
Since I am not on here very much, I will post replies to some common questions I have been asked.

1 - Sorry, but there is no current production of Scepters. The last ones were built by me and FuseWorks in 1997.

2 - No. I have never produced a "partial kit" of any design. All Scepters were ARF. The reason for this was that there were a lot of VERY critical layup steps, bonding methods and alignment jigs needed for the design. Like any extreme airframe design, its not just the form, but what's under the skin that is critical. Every completed airframe was finalized and jigged by me personally.

3 - Yes. I think it goes without saying that anyone can build up a "homebrew" design of anything based on anything. Knock yourself out. BUT please DO NOT call it a Scepter or use my name or WPA to describe it. It's your work and if your doing it right, you should want to take credit for it!

4 - No. I have never given permission for anyone to produce or reproduce (Knock Off) any of my designs. Yes, people have asked but please see #2 above. All the original molds for every WPA design have remained in my possession since they were returned from FuseWorks in 97. Use of my name, WPA or my designs name to sell new stuff is dishonest.

5 - Why not let someone reproduce the design? Because its not that easy. The last time someone asked to reproduce the Scepter, they could not believe all the detailed steps involved, the materials, the milling of...Continue Reading
Posted by WPA | Mar 03, 2010 @ 03:59 AM | 5,140 Views
I rather odd College friend of mine had the unusual habit of repeatedly punching his fist against inatimate objects. Phone poles, doors... it didn't matter and I figured this was just the fall-out of student stress. He would often Really punch something over and over again, stop, smile, and walk away. Curiosity finally got the better of me and one day I asked the obvious "Why do you do that!". Grinning, he sort of leaned in to tell me his secret, "because it feels SOOOO good when I stop!".

Having the FURY unfinished for 13 years has often felt like repeatedly punching my fist against a wall. Every time I would see that large mailing tube wrapped in now brittle yellow packing tape, it was another crack on the knuckles. Seeing the polished wing molds tucked away in storage "fwack". A friend ask "did you finish THE plane yet?" "thunk". I always told myself "it is going to feel soooo good when I stop doing this to myself".

I have had no shortage of "immediate" priorities. The graduate study at SCI-Arc was intense. Going from zero time to a Commercial pilots license was even more intense. Work. Moving. Then moving some more. Buying a home. Which leads to much more work. Having two kids. Really enjoying my family. The list goes on. BUT, it's my family that is most important to me! I am what some might call a very "dedicated" father. Like most dads, I would do anything for my children. Period!

I mention this because a couple of weeks ago by son Zackary, now 7, came up to me smiling. He whispered that he had "found something" downstairs and wanted to show it to me. Crawling into our storage room I found the #21 Scepter. It had been very carefully and neatly laid out on the carpet. "What is it daddy?" Zack asked. "Well... its a glider sweetheart" his eyes really lit up and he took me by the hand. "daddy? When are you going to take me flying....?"
Posted by WPA | Mar 03, 2010 @ 03:40 AM | 5,161 Views
When I was teaching at CU Boulder, I always liked to start my first day of class's by drawing a teeny tiny little dot on the chalkboard as students walked in. Right at the bell I would begin with "Lets say this is how much you know!" I would point to the tiny dot which was now suddenly offensive. "And this is how much you don't know!" I would wildly swing my arms around the empty chalkboard until I could feel the glare of every student warming the back of my head. "Except YOU" I would spin and randomly pick the closest person. "Come up here and show me how much YOU know! It's OK, just draw a circle around that dot and show us how much YOU know". The circle drawn was alway much larger than the dot and always followed by my most sincere "Thank You" and "What's your name?". "Well, what's your name, thats a much larger circle of what you Don't know!". Most heads would tilt to the side but the brightest kids would often grin and softly nod.

The Scepters worked! They worked really well in fact. So much so that I started to think about that stupid little dot on the chalkboard. "Was the Scepter really that little dot?". Was I being that stupid little dot all tiny and safe...? Dale would just stare when I got like this. "Your paranoid" he would grin. Like a big brother, he was really good at ignoring me when I acted stupid. But I had pretty much decided. The new plane was...Continue Reading
Posted by WPA | Mar 02, 2010 @ 03:21 AM | 5,312 Views
My dad once told me "to err is human... but to really $%@# up takes a computer!"..... boy, I was really hoping my dad was wrong!

I knew that "the wing" was being cut that day in Nebraska. Like the delivery news of a child, I was all over that phone on it's first ring. "Mark? It's Sam, the first one is coming off the machine now!". I don't know what was more thrilling, the fact that our first lofted wing panel had just been successfully cut or the noticable excitement in Sam's voice! What I did know, was that it was going to be one very long week before Dale and I could make the drive from Denver to Plattsmouth to pick up our treasure!

And treasure it was.... and just as heavy. The optimized wing panels had been cut out of 1" and 3/4" thick aluminum plate! The tool pathway lines were clearly visible and they were still oily from all the cutting fluid. They were beautiful! All four panels were lined up along an inner wall at Idea Engineering for everyone to see. Sam was very excited and gave us the grand tour. It was fun to see all the interesting projects and hearing the childhood stories of Sam and Dale growing up. They were close. It was only two short days before we had to go home. But there was work to be done. Little did I know at the time, but this new wing was going to lead me to a completely new design.
Posted by WPA | Mar 02, 2010 @ 02:01 AM | 5,376 Views
Sam was one of those super scary smart sort of Aero-Engineers. His design antics at Lockheed got him sent to the SkunkWorks. His design antics at the SkunkWorks got him sent to the 117 program. You get the idea. His talent or "gift" for aviation was in getting computers to fly, well... just about Anything!
Fortunately for the hobby, Sam loved flying RC gliders... and Sam and my flying buddy Dale were also very close friends.

It was 1995 and Dale and I had a new toy called the Scepter. "Sam is gonna love this thing" Dale said as we rushed our gun case through screening at the airport to meet Sam between flights out on the Concourse..... I did mention it was 95 right? Anyways, out on the Concourse the gun case was opened to reveal the first Scepter prototype. Although I had only known Sam for a few minutes, the gleam in his eye when handed our shiny new toy was all too familiar. Dale was grinning from ear to ear and we could tell right away, Sam was IN!

It was several months later and I was out in California visiting my sister. I was tracing out my very first F3F fuselage in Daryl's shop, Maverick Technologies when I got a call. It was Sam and he wanted to send me a fax. I was REAL excited and knew what it was about. Sam was done "optimizing".

Now back in 95 "lofted profiles" were not the norm like they are today. In his spare time, Sam had been tinkering with the Scepter in a program he once wrote called Vortex...Continue Reading
Posted by WPA | Mar 01, 2010 @ 02:29 PM | 5,091 Views
You may have noticed that I skipped over the second design. I guess thats because without ever having seen the plane fully completed and flying, their is not that much for me to tell. The design was a collaboration of sorts with Daryl Perkins whom I met in Kansas at the Sig/Las Slope Race. Anyone who has seen Daryl fly knows he is the real deal and alot of fun to hang out with. He was living up near my sister in Petaluma, CA at the time and I was no stranger to the Bay Area growing up. I was already scheduled to visit my sister that Spring anyways so packed a couple of my "new" Scepters for the trip. Daryl and I hooked up during this spring Cali visit and I got to watch some great Slope Racing and meet some great people all while testing the Scepter prototypes. I was really absorbing everything that was going on around me! Carefully watching the slope racing and planes, my mind was filling with ideas for an F3F and a 60" racer. To make a long story short, with Daryl's input, an all new F3F plane was was being tested in Cali about 8 weeks later. The raw prototype fuse, wing and v-tail were shipped from Colorado to Daryl for final assembly and finish. This plane may have been called "WhipLash" at the time and was unfortunately lost during testing. Daryl's opinion of the plane was that "it was crazy fast and couldn't pull on a winch". I was happy! It was going to make a great F3F! Only the first plane was completed and flown. I did produce a second "partial kit" of this plane for my buddy Dale before I left for CA in 1997. This Partial Kit we called the ShockWave. All of the original templates and original molds of this plane survive in my posession.

SO! That's pretty much an outline of WPA designs that flew between 1995 and 1997. The Scepter was by far the best known/produced and definitely the "Signature" aircraft of WPA.

.... There is one other WPA design that needs to be mentioned though. It was to be the Scepters replacement! Her name was FURY.
Posted by WPA | Feb 28, 2010 @ 10:53 PM | 5,392 Views
Hairstreaks are a type of Colorado butterfly by the way. This was my fourth design and only the second HL I had ever owned (first was a Mosquito). The Hairstreak worked pretty well for a first try at HL design. When the "sod farm" crowd at the RMSA in Denver saw this plane they pretty much "called me out"! I had never entered a Thermal (or even a handlaunch) contest before and the plane wasn't really developed yet. Still, I took the bait and finished second out of 15. I was happy but also realized that Selig's "latest greatest HL airfoil" had a very unique personality. My thoughts were that this "wonder" section had to be kept very simple (rudder, elevator, poly wing) or full house to have complete ability to manipulate the wings trailing edge! Micro F3B Handlaunch anyone?!? There were only 4 HairStreaks made and one was delivered to Ed Slegers. Only 4 made was great news to Steve at Fuseworks, he really hated trying to roll out the lap seam in that tiny tail boom.

05.25.10 - A #5 Hairstreak has turned up belonging to Fred S. I had forgotten all about this plane as it was to be completed by Dale and is the "full house" version.
Posted by WPA | Feb 27, 2010 @ 05:03 PM | 5,168 Views
So here is one for the "bank and yank" crowd! If you want to talk about "obscure" and "unobtainium", you will really love this one. Following my trip to race in Kansas; Dale, Fred and I became very interested in the "new" 60" class that was getting huge in CA. It was a few months after coming back from a large slope race in Cali when I had a "third" WPA design to thrown off a cliff. It was called Salvo... nope, wait, everyone hated that name... I mean Fusion! It was called Fusion, a full house 60" with a triple taper (slight poly) wing and v-tail. I was running a VERY thinned version of the 6062 and could not believe how fast this plane was at very light wing loadings. It was a Runner and flew ALOT in 1996. Like the Scepters and most stiff 60's, the Fusion loved to have lead in the belly and then Bungee launched (the 1" dia garden hose variety)! Unfortunately I did a glassed together three piece carbon wing (go ahead and laugh) and yup, it failed... at the glass...... during a bungee launch! Heavy Sigh. It was a spectacular destruction and the very first Fusion prototype after all. I just had so much fun flying it and everything was performing so well, I forgot it was really a "test" bird. Fusion #2 was built in early 1997 with a full span carbon poly wing. The #2 prototype has not yet flown as of this writing.
Posted by WPA | Feb 27, 2010 @ 03:54 PM | 5,030 Views
The dimensions of the current Scepter are shown below. I say "current" because there is only one of them... and I am a designer... which means I "Loved to Change Things"! I guess it could be called a V3.1 because it had a few small things on it being tested for a new plane (note the high taper v-tail). This drawing was quickly made to document the plane that I was flying and testing in May, 1997. This is Scepter #21.
Posted by WPA | Feb 27, 2010 @ 03:13 PM | 4,892 Views
If you have specific questions about the Scepter, post it here. I will do my best to answer it whenever I am on RC Groups.
Posted by WPA | Feb 26, 2010 @ 06:54 PM | 5,440 Views
It was an accident while Dale and I were "Sceptering". Chasing each other in a series of giant up the face loops, we hadnt noticed the plane coming from behind. It all happened SOOO fast! Screaming vertically up from below like a surface to air missile... CRACK!!! My plane just re-kitted a Jade Impulse! Oops. My Scepter was in a vertical flat spin with the right wing panel flopping all about... then crunch. So much for the original 2 Scepter prototypes. Both birds were totaled! The majority of damage to my Scepter was caused by "deceleration trauma" with the planet. The Impulse's balsa/foam wing had exploded on impact near the wing root, detached and then it was "bombs away" for the fuselage. All agreed, it was pretty much a glorious death for both planes!

Sort of on a dare from the slope bums, the #2 wings were trimmed to 60" exactly. The right lower carbon skin was repaired/rebonded in the bag and tip blocks shaped. After primer... wow, this wing set may fly again?!? They did!

The Inter-Scepter as it was jokingly called worked remarkably well. Pretty much a plug and play for any Scepter fuse. Impressive roll rates and great energy retention in the huge stuff. Only two Inter-Scepter wing sets were "originally" produced... no telling how many were done custom!
Posted by WPA | Feb 26, 2010 @ 05:52 PM | 5,244 Views
I figured you could always tell alot about a slope plane just by examining its wing rod. The Scepters had a 7/16" x 12" steel wing rod for only a 2m span! The fuselage "wing box", where the actuators were held was an overbuilt hoop of 45 degree biased glass layers that ran around the fuse opening for the wing drive pins. The bellcrank actuators themselves were machined steel with ball bearing pivots. High output servos drove 4-40 hardware and all this mass was centralized near the CG point. For having such a long tail moment, Scepters also needed little or no nose weight to run the aft "performance" CG's we liked. This kinda gets at the heart of the Scepters performance. Like carrying a pole in a high wire act, the long wing and tail moments of the Scepter allowed us to run crazy aft CG's points with little or no wing incidence angle to the tail. Everything was centralized, overbuilt and packaged in a super slippery airframe!
Posted by WPA | Feb 26, 2010 @ 02:41 AM | 5,847 Views
You would almost have to look at a V.2 and V.3 Scepter side by side to see any differences between them. The give away is that the tips on the V.3 are slightly swept back and have a greater chord. The airfoil was also changed to a 6062/6063. The V-tail also had greater chords but with a bit less span. The slightly larger tips gave a bit more roll authority and the 6062 made the plane easier to manage at low to moderate speeds. Only 3 of the V.3 Scepters were ever made.

It was now the summer of 1997 and I was getting married to my high school sweetheart. Beverly had just finished her Masters Degree and we were moving to Los Angeles so I could do mine. All the WPA molds were returned in July of 97 and all the tooling was boxed for Cali. WPA mold(s)?? Yes, I am refering to the Scepters younger siblings. You see, there were other even more obscure WPA design prototypes flying by 1997 that very few have ever seen. One of which even I have never seen completely finished!!! I will get into these later:

Fusion - A full house 60" racer
Inter Scepter - Clipped wing 60" Scepter
Hairstreak - Hand launch glider
Shockwave - F3F prototype designed with and flown by Daryl Perkins

And those that had not flown... yet.

Fury - If you think the Scepter was extreme... you ain't seen nothing yet!!!
Posted by WPA | Feb 26, 2010 @ 01:36 AM | 5,689 Views
With a new fuselage mold and the wing lay-up schedule figured out, planes were being produced for customers. The fuselage wing actuator openings were reinforced with 4 biased layers of 6oz glass that was sandwiched between two full length 8oz layers of glass. 1" Kevlar tape ran the full length of the fuse as well.

I mentioned my flying buddy Dale, but I may not have mentioned that he was also a pilot for United Airlines with time to kill while on Layovers. One of his favorite layovers was in Hong Kong because it had a very active slope community and pretty much no flat land anywhere to be seen. He often took a slope plane with him on trips and flew at a mountain slope called Clearwater Bay. After taking his Scepter with him on one of these trips he came back with an order from Tung. Tung was a local hobby shop owner and slope nut in Kowloon City that Dale had been friends with for awhile. On Dale's next trip, Tung was delivered his plane. On the following trip after that, Dale came back with a cash deposit for 10 more Scepters! What did I get myself into here? I had already handed off fuselage production to Steve at Fuseworks, Bellcranks were EDM wire cut at Idea Engineering in Nebraska and I was busy bagging wings and tails. It took a couple of months but all 10 Scepters in this order were hand delivered to Hong Kong. Each one had already been sold by Tung before it arrived.

It was around this time that I began tinkering around with a revision to the wing planform and the airfoil selection. A third version was in the making.
Posted by WPA | Feb 25, 2010 @ 10:56 PM | 5,770 Views
The first Scepter prototype had a ply wing and tail skin over blue foam. It was flown at Bear Creek Reservoir, Littleton CO in March of 1995. Right out of the gate the performance was impressive! The concept of long inertial moments on a very strong and slippery airframe was working. Structurally, I was quickly finding the weak spots though (cracked fuses at the wing pin cutouts, tail skins delaminating on landing, etc). The flying surfaces were solved on the #2 bird with a carbon skin and tail but the fuse needed a major rework. It was just too slim and didn't have enough structure where it was needed. This did not stop Dale and I from going to Kansas with the #1 and #2 birds for the 95 Sig/Lass Slope Race. Conditions were light to moderate but this also showed something else the Scepter could do really well, Fly Fast in light air! I won the Unlimited race. Funny the twists of fate. At the start of the event people thought the plane was a joke. By the end of the event, all my flyers were gone.
Posted by WPA | Feb 25, 2010 @ 10:12 PM | 5,505 Views
So arriving home in Colorado, I knew the plane I wanted to make. It would be a two meter pitcheron. If done right these are the simplest of designs with the fewest parts. It would be a V-Tail. Less drag and with no linkage weight out back I could have a longer tail moment. It would also have a high aspect ratio wing. This would give great airfoil efficiency if the skin structure could be strong enough. The underlying concepts were Simplicity, Major Centralized Structure and ALOT of inertial dampening from long wing and tail moments... or stability. Below is my original Scepter sketch. I would have a prototype done in 8 weeks!
Posted by WPA | Feb 25, 2010 @ 09:50 PM | 5,631 Views
I say "My" Shredder because other than the fuse (which I modified) and the cores (which I modified) everything else was custom. I wanted to build a brutally over-structured pitcheron and could care less about weight (actually, maybe the more the better). I also had an idea for a "compliance" linkage that I also wanted to try out. This plane flew twice during the Soaring Jamboree (94 I think) and suffered a major servo failure during the second flight. Made a very impressive crater! It didn't matter though. The plane was a screamer and the whole drive home to Colorado I knew for certain the plane I wanted to build! It would be safe to say I had "clarity".
Posted by WPA | Feb 25, 2010 @ 09:21 PM | 5,552 Views
My flying buddy Dale and I were pretty much the "Big Air Nutz" on our hill. You know the guys and you may be one yourself. When the rocks and gravel are blowing up the hill and most are running for cover... you put on the goggles and grab your buddy for a launch! Anyone who has flown the eastern foothills of Colorado during a storm in the Rockies knows that mother nature can get pretty pissed off! 70-80 MPH winds were not uncommon in the Spring and Fall but these were the conditions we lived for! Below are few of the important "inpirations" that led to the Scepter. The one that came closest to the mark was "my" Shredder.
Posted by WPA | Feb 25, 2010 @ 08:25 PM | 5,249 Views
The Scepter was the first "Clean Sheet" design I had ever done. Like most people, I seemed to have a habit of EXTENSIVELY modifying kits! Sometimes to the point of the planes being almost un-recognizable for what they originally were. It was not a big leap for me when my friends told me, "Mark, you should just do your own planes". I did.
Posted by WPA | Feb 25, 2010 @ 05:43 PM | 5,436 Views
Wilkerson Performance Aircraft, or WPA, was created in 1995 following a very inspiring trip to the World Soaring Jamboree in Washington state. The "signature" aircraft of WPA was called the Scepter. A high AR 2M pitcheron with extreemly long inertial dampening moments. The Scepter was a great performer and underwent three variations the second of which was mostly production for customers. Twenty-One Scepters and two clipped wing Inter-Scepters (60" span) were produced between 1995 and 1997. Of these planes, Eleven Scepters and one Inter-Scepter were sent to Hong Kong.

I have never had a "Blog" before but have noticed some interest in what is now refered to as "unobtainium" slopers sprinkled about in a few threads. For anyone who is interested, I will be happy to provide more information, history and photos about WPA as my time allows. I say WPA because the Scepter was only one of several obscure designs that we were flying in 1997 when all customer production was put on indefinite hold.

Full Blog here -