Author Topic: Helio N700AA #1 'Hellacious Helio'  (Read 16098 times)

Doug Johnson

Helio N700AA #1 'Hellacious Helio'
« on: April 24, 2011, 10:12:12 AM »
Helio N700AA #1 'Hellacious'

Garrett TPE-331-6 (750 SHP) (MU-2) with water injection (200hp boost), super swamper tires 38" on the mains, F-101 Voodoo nose wheel assembly. Extended wing span for a total of 175 gallons of Jet-A....Empty weight 3400 pounds. And a 106" prop....!!!!

Wing-x for the Helio. They hold extra 25 gals ea fuel for the Turbine. If they would have gotten rid of those ugly end plates and put Hoerner tips on it would have looked better and worked much better.
« Last Edit: February 29, 2012, 05:43:53 PM by Doug Johnson »


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Re: Helio N700AA #1 'Too loud to bad'
« Reply #1 on: April 24, 2011, 10:20:57 AM »
I personally know the owners of this hybrid Helio, not sure why they went to such extravagant measures to get this thing here. I can tell you this, the airplane no longer looks like this.


Re: Helio N700AA #1 'Too loud to bad'
« Reply #2 on: April 24, 2011, 07:06:04 PM »
What happened to it?


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Re: Helio N700AA #1 'Too loud to bad'
« Reply #3 on: April 27, 2011, 07:49:16 PM »
It is now back on tail-wheel and being scaled down from it's original form.

Doug Johnson

« Reply #4 on: December 27, 2011, 02:32:19 PM »
An EAA member, gave me a copy of an article in Nov 2004 sport Pilot.


Budd Davisson EAA 22483 EAA Sport Aviation 35

Of all of the airplanes populating Wittman Regional Airport during EAA AirVenture Oshkosh 2004, perhaps the hardest one to miss was a Helio that stood on tiptoes with knobby tires. Or, at least, it was what was left of a Helio.
There was a whole lot more of Jay Jensen (EAA 550657) and Ken Bjork in that airplane than there was Helio, and it towered over airplanes around it like a stork looking for its next meal. On top of it all, Jay and Ken were having more fun with the whole thing, and life in general, than you typically find even among the most experimental of the experimental crowd. It would be easy to take one look at their airplane and decide the lunatic fringe had moved to town, but that wasn’t the case at all.

What you have here, in what many have called the Helio from Hell, is two guys who are having more fun than should be allowed. During the time I spent with them, at least one of them, and usually both, was cracking up. That made it easy to envision an interview accompanied by a laugh track.

Jay Jensen and Ken Bjork of Salt Lake City are, in some ways, a very odd couple. Jay is a stockbroker— albeit the most enthusiastic “up” stock broker we’ve ever met. It’s hard to picture him in an Armani suit with a $200 necktie.

That being the case, it’s impossible to picture his partner in aero-crime, Ken, in a suit of any kind. He is, by his own description, a “maker of neat stuff”—at least he is when he’s not working his real job flying a Citation II for an oil company. Ken says he does everything possible not to let his corporate jet job get in the way of building airplanes.

“I came out one day and Ken had these truck air horns attached to the nose gear and I thought, well, let’s go for the gold and get some real train Horns.” —Jay Jensen

“I found the nose strut in a surplus yard and brought it out to the hangar as a joke, but the next time I came out, Jay already had it welded in place.”—Ken Bjork

Despite their differences, both of  them are grease-under-the-fingernails types of the highest order. And  both of them love the backcountry of Utah, which is how and why this Helio mutant ever saw the light of day in the first place.

Both of the guys are second-generation pilots. Jay’s dad owned the Salt Lake City Beech distributor for years. The Jensens used to fly into a favorite mountain strip that was 1,200 feet long at 8,000 feet msl. This is a good trick in anything, but they were doing it in a Queen Air, making it appear that Jay came about his tendency toward the extreme, honestly.

Ken says, “I started flying at 5 years old in the right seat of my dad’s 182.” The elder Bjork worked in the construction industry, and that’s how Ken was first exposed to the Helio Courier.

“They used one to go to the construction sites and I was always riding along,” Ken says.

While Jay went to college and eventually joined a high-end stock brokerage, Ken began working on airplanes almost immediately, including the construction of the first Lancair 4P. He met Jay through his brother.

“My brother was a CFI and he was flying with Jay,” Ken says. “I’ve always liked Helios and so has Jay, so my brother introduced us. You might say things went downhill from there.” Lots of laughter.

The trip was aided by a book Jay bought called Fly Idaho. It detailed many of the back country airstrips and other mountain destinations.

“I literally ate it up,” Jay says. “I figure that $20 book cost me hundreds of thousands of dollars.” More laughing.

Jay got into the backcountry thing in a very serious way and cut right to the bottom line, opting for a Helio Courier almost immediately.

“It was 1995 and I bought an H700,” Jay says. “I was checked out by Larry Montgomery, known by most in the field as Mr. Helio. Larry was the original Helio factory pilot and what Larry gave me was more than simply a checkout. Larry taught me how to fly a Helio the way it has to be flown to safely play in the mountains.

He had worked with JAARS for years and knew the Helio and the kinds of operating conditions I’d be working in as well as any man alive. To a very real extent, he taught me how to fly all over again.”

Partners in Crime

Ken and Jay are absolutely simpatico (Ken refers to themselves as “Darryl and Darryl”) in terms of what they expect airplanes to do and the list really isn’t very long. Their dream airplane had to pretty much ignore density altitude because hitting ground at 8,000 feet is common where they wanted to go.

The airplane should land at a fast walk, stop immediately, leap tall trees and canyon walls in a single bound, and do all of this while carrying a good sized load. Oh yeah, on top of that, it had to do it on runways that were both incredibly short and incredibly rough.

Basically, they wanted to be able to go where no plane dared go before. The Helio Courier series of aircraft came close to satisfying their demands, but “close” wasn’t close enough. After every trip in a Helio, one or the other would say, “Yeah, it would be great if only…”

This went on for years, with their daydreams becoming ever more fanciful. Then one day they realized that between the two of them they possessed all of what was needed to realize their dream: Ken was a maker of neat stuff and Jay was a maker of money. The conspiracy was hatched.

Jay says, “It was actually Ken’s idea, so I guess I should be blaming him for the last couple of years.” Laugh, laugh.

Ken chimes in, “All I wanted was more wing and tip tanks. Jay, however, also wanted more power. Lots more.”

They started out with most of an H800 that originally carried an eight-cylinder, 400-hp Lycoming IO-720 in
it. But they had a few problems with the stock design: not enough power, not enough wing, not enough fuel.

“We figured we could take care of  two of our requirements by extend-ing the wing with airfoil-shaped tip tanks,” Ken says. “We made those out of Nomex honeycomb and Hexcel Thorstrand for better lightning protection. They added a couple of feet to each wing and hold 25 gallons apiece.”

“Yeah,” Jay laughs, “but it means we have to plan our fuel stops based on the size of the ladder the FBO had. It takes a lot of ladder to get at those tips.”

In the process of building the tanks, they extended the wing spars and incorporated landing lights. The tanks are plumbed through a set of Fawcett pumps that transfer fuel into the mains, rather than being plumbed to a central valve and directly to the engine.

The longer wings induced more changes. “We needed to build new ailerons, so we did those in composite too,” Ken says. “They are carbon fiber over foam cores. At the same time we added aileron trim tabs that are run by MAC servos. With fuel that far out, you need the ability to trim it in roll.”

They could make the necessary changes because the H800 they started with was a beefy airplane. Jay says, “The H800 is a Part 23 airplane that has a really heavy stainless steel carry-through structure. The airplane is full cantilevered and super strong.”

For power, they didn’t mess around. They bought a Garrett TPE-331-6 that is shaft-rated at 750 hp at 5,000 feet and 100°F out of a Mitsubishi MU-2. But even that wasn’t enough. “We copied the design for an AWI [alcohol/water injection] unit off of a Fairchild Metroliner,” Ken chuckles. “This blows an alcohol/water mixture into the engine and is good for an extra 200 hp on a hundred-degree day.”

Do they have a lot of hundred-degree days in the mountains of Utah? “Well, no,” Jay admits, “but you never know. You have to be prepared.” They both laugh.

To put that kind of horsepower to work takes a lot of propeller. In this case, it is a whopping 106 inches in diameter. By comparison, the longest prop normally seen on a 250-hp Lycoming is 84 inches. The huge prop meant doing a little landing gear modification.

“It was a taildragger at the time and we made new legs for it, but with the big tires, long legs, and even longer nose, you couldn’t see a single thing anywhere ahead,” Jay says. “The angle was incredible. It was totally blind. We even had a camera up there with an in-cockpit monitor to help us taxi. It worked really well, but we had no depth perception.”

“Then,” Ken adds, “we fabricated a hydraulic extending tail wheel strut plumbed so we could hit a button and it would lift the tail into the air a foot. It was fun to land in that configuration, but way too hairy.”

Because the 800-series Helios are structurally equipped to be either nosewheels or tailwheels, they decided to try putting the little wheel at the other end of the airplane.

They brought in Bob Casebeer, one of the original Helio engineers, who had designed the original Helio trike and had worked on the turbine-powered Helio Stallion.

“Bob had a lot of fun because he got to do a lot of things on our airplane he always wanted to do at Helio, but never got the chance,” Jay says. “Actually, Ken wanted to make it a quad-gear, using both the
front gear legs and a rear set so it had four wheels. And he was serious. He actually made the whole setup. It was incredibly sturdy but we didn’t have time to adapt the hydraulic rock crawler steering mechanism in time to make Oshkosh. Maybe next year.”

From a distance, the main gear, which now mounts where the factory would have put it, looks as if it’s a spring gear, but it’s not. The legs are over an inch thick and, although they may give a little, the real shock absorption comes from hydraulic shock struts attached to trailing link, knee-action units at the bottoms of the legs. “Each of the shock struts is plumbed up to a central accumulator in the fuselage,” Jay says. “We have a gauge on it and can change the pressure and spring rate of the gear by moving a valve. The nose gear is a dual-tire unit off an F-101 Voodoo jet fighter and the steering cylinder is off an F-111 fighter/bomber. No one can say we don’t think big.”

That nose gear was the start of what makes this Helio so outrageous.


Ken describes how the nose strut came about. “I found the nose strut in a surplus yard and brought it out to the hangar as a joke,” Ken says, “but the next time I came out, Jay already had it welded in place.
It actually works really well and is light because a lot of it is made of beryllium. We both thought it was very important to incorporate parts that had been stressed for supersonic speeds if we were going to use them on a Helio.”

This started a tit-for-tat game that gave the airplane some of its more memorable features.

Ken brought out tires and rims from a Hummer as another joke, so Jay got even by putting on the rock crawler tires and rims. They plan on shaving the tread off like the Sherpa guys do. Maybe. “They look so great knobby,” grins Jay, “that we think we’ll wait a while to do it.”

Keeping with the rock crawler theme, Ken added his next touch.

Jay says, “I came out one day and Ken had these truck air horns attached to the nose gear and I thought, well, let’s go for the gold and get some real train horns.”

But it wasn’t as simple as all that.

“First of all, you don’t run down to your train junk yard and buy an old horn,” Jay says. “I had to do a fair amount of Internet snooping before I came up with the manufacturer that makes train horns, then locate a dealer. The company was Air Chime in Vancouver, and I bought a KLA-3, which has U.S. tuning as opposed to the Canadian tuning.”

He laughs as if knowing the U.S./ Canadian difference is of immense importance and, of course, it is to him.

“The first couple of times we flew it with the horn,” Jay says, “we honked it on downwind a little too much and the airport got a call from someone who said this train kept going by and he couldn’t find it and was worried.”

But, perhaps surprisingly, the horn does have practical applications.

“The horn works well in the back-country, because you can honk it on final and chase all the wildlife—mainly your buddies—off where you’re going to land,” Ken says.

The pair participated in other hijinks as well.

“One of the more fun things we did while building it was the taxi testing,” Jay says. “The fuselage separates behind the wing and we had the forward part of the fuselage, without the wings, on the gear and we were doing high-speed runs down the runway. We timed it and we can do 0-60 mph in about 3 seconds. We can do 0-100 mph and back to zero again in 12 seconds. What a kick! The only problem we ran into was accidentally triggering the alcohol/water injection system while the prop was in beta. Two hundred extra horses hitting instantly while in reverse torqued our ‘jet car’ up on two

Like we said, these guys are having way too much fun.

When they were all finished they had an airplane that weighs 3,300 pounds empty with 258 square feet of wing area.

It is of some interest that they encountered little or no resistance to certifying the airplane as an amateur-built experimental rather than as an air show/exhibition airplane, with its attendant restrictions.

The 51 percent certification rules that apply to kit builders clearly spell out what operations the builder has to carry out for each part of the airplane (wings, ailerons, landing gear, etc.) to have those operations count toward their 51 percent. When Ken and Jay totaled it up, it was no contest. They had taken the airplane so far apart and re-designed and rebuilt so much of it, it was no longer a Helio Courier. As it happened the FAA agreed. But other roadblocks remained.

“Because it’s a homebuilt with a turbine, we had to write our maintenance and inspection manual as part of our preflight licensing inspection,” Jay says. “We started out with Mike Robinson at the Portland FSDO, who had experience working with Lancair on their amateur-built turboprop maintenance manual. It took a little while to adapt that format to our project, but I feel we ended up with a first-class engine and airframe maintenance manual.”

That out of the way, the airworthiness inspection came next.

“The airworthiness inspection had to be done by the Seattle MIDO, no different than if it was a brand new kit airplane or a brand new Boeing,” Jay says. “When inspection day came, we happened to have four MIDO inspectors in town doing inspections on Williams jet engines being built for Citation jets. I asked them to please not make fun of ‘my baby’ because I was sensitive and, do you know what, it didn’t help at all.”

Jay says the airplane had the customary squawks, as the builders expected, but the airplane passed with flying colors.

“Keep in mind, however, getting 51 percent approval is not for the faint of heart. You need to let the MIDO know up front what you are planning to do and get it cleared first. Then you have to document it like crazy along the way,” Jay says. “The FARs allow a great deal of latitude under experimental—amateur-built. You just have to follow them. That’s why our stickers say ‘Really Experimental.’ This airplane
really is, and we’re not done yet.”

So, How Does It Fly?

“There is no way you can push a Helio faster than 135 knots indicated, even with 750 horsepower,” Jay says. “However, up at altitude, around 17,500 feet where we’re limited by tail pipe temps, we’re truing 150 knots—and that’s with 38-inch tires, which isn’t too shabby. We have Kevlar oxygen tanks onboard and can go for five hours at that altitude. Plus, with that prop and the flaps, we can slow down and come whistling downhill at over 3,000 fpm.”

The power does show up on takeoff, though. With 20 degrees of flaps, the airplane is rotated after a 300-foot ground roll. It makes 2,400 fpm with a 2,000-pound payload and can maintain that climb attitude all the way up to 24,000 feet, with an average climb rate of 2,000 fpm.

“The engine is a constant speed turbine, so your thrust lever is changing the blade angle, which gives very precise control of your thrust. This really helps on short field approaches and rollouts,” Jay says. “The second we touchdown, we can go into beta on the prop and stop easily in 200 feet. The brakes, by the way, are off a Caravan, so they help a lot too.”

Also installed is an Ayers/Thrush Ag Air spray system, which so far has not been deployed in anger.

“We can drop right down over our campsite and spray it for mosquitoes,” Jay says. “We could easily become the most popular airplane at some of the Northwest fly-ins, where mosquitoes are a real problem.”

What are their current plans for the airplane?

Jay grins and says, “Hey, what else? We’re going to take it out and get it dirty. Really dirty.” And both of them start laughing hysterically.

Garrett TPE-331-6 (750 SHP) (MU-2) with water injection (200hp boost), super swamper tires 38" on the mains, F-101 Voodoo nose wheel assembly. Extended wing span from airfoil shaped 27 gal tip tanks for a total of 175 gallons of Jet-A....Empty weight 3400 pounds. And a 106" prop....!!!!

« Last Edit: January 15, 2016, 10:04:07 AM by Doug Johnson »


Re: Helio N700AA #1 'Too loud to bad'
« Reply #5 on: December 28, 2011, 07:58:33 AM »
Is the H800 really a Far 23 plane ?



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Re: Helio N700AA #1 'Too loud to bad'
« Reply #6 on: December 28, 2011, 03:31:31 PM »
Budd Davisson wrote this article right after the Helio 50th at Airventure. I was hired to answer questions and guard the airplane for all 4 days it was here.

N70AA is a Helio 700, not a 800 for starters and the engine is a TPE-331-6 from the MU-2 rated @ 840 SHP and with ADI puts out 900 SHP for emergency ratings.

N700AA was originally a Part 23 airplane, and then after the installation of the F-101 Voodoo nose-wheel assembly and numerous other radical modifications it was clearly something else with an empty weight of 3400 pounds!!

Doug Johnson

Hellacious Helio
« Reply #7 on: December 28, 2011, 07:35:50 PM »
I called Jeff and asked where the 750 hp thing came from, since I know virtually nothing about turboprops and he sent me this.

Mitsubishi MU-2P, Powerplant: 2 × Garrett TPE-331-6-251B or -252 turboprops, driving 4-bladed propellers, 840 shp, flat-rated to 715 shp each.

He didn't know where the 750 hp came from He says The MU-2L is  2 × Garrett TPE331-6-251M rated at 776 shp each.

I also asked if it was a 7 or an 800 he says he spoke with people at the fbo where he stopped and they said it was made out of a 700 and an 800 the front portion is an 800 and the rear portion is a 700.

Do you know which two airframes it was made from?

« Last Edit: December 28, 2011, 09:30:46 PM by Doug Johnson »

Ray Dorsey

Re: Helio N700AA #1 'Too loud to bad'
« Reply #8 on: December 29, 2011, 11:20:36 PM »
Is MR. Casebeer On line to mke a coment or two onthe subect A/C or other comment,s for helio


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Re: Helio N700AA #1 'Too loud to bad'
« Reply #9 on: December 30, 2011, 02:58:12 PM »
Helio N700AA was originally built as a H700 from the factory, Jay Jensen bought that airplane sometime in 92 or 93, when the plan was to extensively modify the airframe to the standards of where it appeared at EAA 2004. The MU-2 power-plant was thermo-dynamically boosted to accept full rated power at 840 SHP rather than have it de-rated. Installed was a 5 gallon ADI tank forward of the firewall.

So if there are components of the forward section from the 800, that may very well be.

The airplane now has been modified back to tail-wheel and the gear re-engineered with much smaller axles and tires. I think there is also a front mounted canard to restore lifting force from the 106" Hartzell 3-blade..

Doug Johnson

Re: Helio N700AA #1 'Hellacious'
« Reply #10 on: February 29, 2012, 05:26:45 PM »
I found a picture of before the Turbine and one showing the 27 gallon wing tips with retractable landing Lt's,  I wonder if the light vertical angle can be varied like they do on ag planes.


« Last Edit: February 29, 2012, 05:42:36 PM by Doug Johnson »

Doug Johnson

Re: Helio N700AA #1 'Hellacious Helio'
« Reply #11 on: December 10, 2014, 02:49:35 PM »
For those of you interested I finally go ahold of Jay Jensen, The owner of the experimental Turboprop.

He gave me permission to post his replies.

My turboprop never crashed, as rumored, and is alive and well. We did change out the main gear legs to spring steel and went to 29”  crop duster tires on the mains, and 26” tires on the nose wheel. It lands so slowly that it was not worth packing the extra weight of the trailing link gear. The removal of the trailing link gear and the 38” Super Swamper tires speeded it up a lot. It trues 175 knots, just like a Stallion. At 5000 feet and 100 Degrees F. it indicates 165 knots in the pattern, matching my P-Baron, with its gear up! 

Despite the rumors out there it has not been converted back to a tail dragger, nor could it be, the prop is too big.

We did build a set of stub wings and a lower carry through including double slotted fowler flaps that are hydraulically actuated. The stub wings are attached at the end of the carry through with circular plates that have a variety of holes drilled in them to experiment with different angles of attack. NASA has a cool program on the net called Foil Sim. It allows a designer to try out different profiles with and without flaps, as well as various angles of attack, at different speeds.

Based on the Foil SIm  modeling our goal is to be able to pick up between 1000 and 2000 lbs. of weight depending on the angle of attack of the stub wing and the flap combo. That will stress relieve the wing back to standard. It also makes it much easier to load with the stub acting as a step. And we can pick up another 40 gallons of fuel in the stub. We have also put in additional bladder tanks in the outboard section of the wing bringing the wing total to 220 gallons, with 40 more in the stub we’ll have 260 gallons. We block plan for 50 gallons an hour, so that gives 5 hours of flying.

The mileage sucks however. It only averages 4 mpg, but it has a real world range of 1000 nautical miles. The stub wing and flaps are fully blown and in the prop blast full time. The blast on takeoff is 205 knots. The differential wind drops to 30 knots at cruise however. For example at 175 knots cruise the prop is blasting 205 knots down the airframe.  We figured that out with a separate pitot and airspeed gauge.

Of interest the prop blast does not cone, it rails straight back about 3 feet from the side of the fuselage. We figured that out on the ground using a hand held pitot and moving it toward the plane until it registered. Guess how wide out stub wings are! Also there is a dead spot with no wind at all on the side of the fuselage sticking out for about 3 inches, caused by the windscreen. Fly around with the doors off and you can stick your hand out and no wind at all, then it hits a solid wall of wind at 3 inches.     
All the structure of the stub wing and hydraulics is built, it just needs the fiberglass skin laid over it, but I hate that stuff. My buddy Ken might get to it later this winter, he’s good at it.

edit I will have to email jay and ask if this will be similar to the King Katmai canard

But we got diverted building a Baja 1000 race truck. There is a new class for the “Sportsman” , no money, just a trophy. We built up a Toyota with a 383 Chevy placed in the rear like a buggy. It has 6 foot swing arms like a dirt bike on the rear, with 3 feet of travel. The front is IFS with 2 feet of travel. It should hit over 100 mph in the dirt.

The 2” roll cage make the Helio cage look like a toy!!

To many toys not enough time, same old story.
 Jay Jensen

Regarding the fuel in the wing of the turboprop, it’s really a simple system.  The wing came with the two 30 gallon tanks per side standard in the 700 and 800’s. We extended the wings about 2 feet on each side with fiberglass extensions.  Those hold 25 gallons each. There are 4 bays  between the wing extension and the outboard 30 gallon aux tank, they collectively hold another 25 Gallons. I measured them up and had Eagle fuel cells in Wisconsin build them.
The wing extension tank and the four bladders are connected at the bottom one to the next. There is a tee in that line to a facet pump that transfers all 50 gallons to the inboard mains. One pump switch with an empty light on a float switch does it.  I wish the original Helio 30 gallon aux tank had a float light.

You have to keep switching the  4 position tank switch in order to see when it has transferred to the mains.

edit this one of the first things I changed I installed two electronics international dual fuel gauges and a separate Cessna style rocker sw for each outboard tank with an on indicator this allowed me to stop transferring for a bit when one wing begins to get heavy
As you know the mains are connected in a Helio but they do not draw down equally and create a fuel imbalance. I got sick of that so I ran another line across the cabin with a pump so I can move gas from the left main to the right and balance it.  Man, do I ever love the experimental category, you can actual fix stuff.


Standby for some pictures next week of the stub wings and the new gear.