By Jim Maddox

2002 Entries; left to right
Co-pilot Callie Johnson, Driver/Navigator-Henry Crocket, Pilot Jim Maddox.
Entered “Delta 1 Tanker”, a Delta Vortex© by Bruce Tharpe Engineering (800) 557-4470.
Aircraft is highly modified to fly for long-distance flights, in a 130 mile race across the desert. A test of; man/women, machine and environment in south-eastern New Mexico.
“Racing against the clock but not allowed to use one.”

This was the first “run” after 18 months of trial and error working out the bugs. Fuel issues kept us out of the first race using this aircraft however not out of the winners circle, we placed 2nd with our high wing airplane.

The 2003 race promises to be “different” including a longer distance portion…..one leg of 100 miles and possibly 2.5 hours of flying non stop for the aircraft. There may be “games for the crew” along the way, like get out and run around the truck and collect objects. It will be a timed event…but no watches or timing devices of any sort allowed, only basic math skills, speedometers (mileage driven, speed traveled) calculators, spread sheets and luck. Our pilot sits in the back of the truck buckled into a swiveling bucket seat with a birds eye view….very comfortable! In a one hour flight we can be accurate enough to land inside of 30 seconds of the target time. Last years 1st place did it in under 10 seconds, 3 separate times. Honestly!

Early Morning Check out of Delta 1 Tanker in the 2002 race.
Callie is getting the H2O and Pilot’s seat ready for travel. Temperatures ranged from 60
in the early am to 110+ by mid-afternoon.

January 2003…..in the beginning……Delta II Tanker on the “drawing board.”
We schemed and modified the already solid, “BTE Delta Vortex” airframe to haul a lot of fuel and operate in an unforgiving and sometimes hostile environment.

Being built as a team effort, 4 of us, 2 men and 2 women, working on various areas and bringing completed parts to the bench to put together. An average workday was about 6 hours. We met one day every so often in a well orchestrated and concentrated effort. It is a nice way to socialize even though 3 of us work together at Jim’s Automotive, Inc. We have all had fun. The newest member of the team is Bridey Kemeny shown here on the left and Callie on the right. Callie is a big part of the Hobbies-N-Stuff staff and has been instrumental in finding some of the weird things I have asked her to find and order.
Thank you Hobbies-N-Stuff!! 293-1217
Thanks to all who helped us work out the bugs especially Stan and Matt.

After much thought and time spent just pondering the “what if’s?” We mounted five, 24 oz. fuel tanks on the CG and one, 4 oz. header tank in the nose. Carbon fiber tubes, Kevlar™ thread “ropes” and balsa blocks hold the tanks securely and help the craft to take hard landings very well…we tested it a lot!

Fuel range will be somewhere around 3.5 hours at full throttle and 90 mph top speed. Tanks shown here are in place, strapped down, plumbed and vaccum tested! Holes in sheeting are re-enforced on both sides with cloth and CA, for fuel tubing access. Secondary lower spar also serves as rear fuel tank access hatch support….funny how that worked out just perfect. Main spars have Carbon Fiber iron-on tape, on all 4 sides, and carbon tubes across top of tanks, which also serve as secondary upper spar, to accommodate all that weight. Six center ribs are covered with 3/4 oz. cloth and thick CA squeegeed in from LE to TE on one side. Servos are moved way back in main ribs for balance purposes. The plans call for them in the nose.

Our “Delta II Tanker” is born!
This photo was taken after day 5 of teamwork. Henry and I were “Bonding”….and sanding. We were very happy to see so much come together so quickly…It looks like a Plane! Battery and equipment hatch between fins looks and works great on the bench, it is well sealed and has lots of extra room which was really only needed for the battery pack. (2600ma Ni Metal Hydride) I was concerned about the effects in flight, it could give it some “UP”…..Not always desirable because that is where loops start, with “too much up!”.

All fuel supply issues appear to be resolved here on this very cool tilt table test platform that Henry built. The engine and fuel cells must work in a variety of attitudes and heat ranges. We needed to prove that the many changes we made in fuel delivery would all work well. It did…… and it does!! It idles for long periods and “snap” throttles up to full throttle in the attitude you see here. The engine is a stock OS91 pump being run on 10% Cool Power and has had one “load of fuel” or about a gallon, run through it during break in. The majority of modifications are in the fuel system. Lines and clunks are all oversized to the next size up. Lots of soldering. Tanks are positive pressurized from the exhaust system without a check valve, this is to assist the pump in its delivery abilities at high angles of attach. OS and most pumps recommend atmosphere vents, which, I found to be a problem for what I wanted to accomplish. By increasing line sizes we effectively decreased restrictions and increased fuel volume without the need for high pressure.

This is, “Delta 1 Tanker” on final approach in the 2002 race, in about 110 degree “NM Sunshine.” Its first 20 landings, the year earlier in practice, were “dead sticks” (meaning engine died) shortly after take-off due to lean fuel supply conditions. They “came and went “, until we installed a YS91 Engine that uses a high pressure fuel system. But it was too late for the race. I found that due to the arrangement of the fuel tanks and all the lines we needed a pressurized fuel system to solve problems associated with lean running conditions. Delta 1 is still flying and will be used as the “Secondary aircraft.” for this year’s event. She has bomb bays in the wing tips for streamers, for Victory rolls, air shows and general showing off. See those “puffy” clouds? Huge dust devils are created by the desert heat rising to make those clouds. Dangerous oversized Dust Devils are everywhere all the time mid-day. Some are Invisible! Large Lava beds create tremendous thermals and it requires a great deal of “pucker power” to fly a good portion of the race. Hence the flatness of my ass (see above photo) and not hers, I was still locked in “pucker mode” at this point. The air is very thin and the aircraft sink rate can be high, especially over the hot highway during final. Luckily it stalls flat. Delta 1’s fuel range is only 72 minutes but it can fly at 102 MPH!

Jim’s invention – “Bush suspension” landing gear works very well, even on heavy models of 15 lbs. (12 or under is ideal). The wheel base was dramatically widened from the plans to 26″. 5/32 music wire has live suspension shocks made from “castration” bands for livestock. Who would have thought? They are small, lightweight, tuff, impervious to fuel, oil and weather. They last forever. Thanks for the idea many years ago Mike!

With engine mounted, tanks in, fins on, elevon’s hinged, Delta II tanker, fatso,….. Weighs 6.2 pounds. We are going to hit 8.5 lbs dry but hopefully not over, because of 7 more pounds of fuel payload. The “lightened servo mounts located in the wing panels could come out….they are mistakes(1st ones on the whole project really)…glued into the wrong side of the wing and left in place only to strengthen the wing center section aft to reduce flex on a hard maneuvers…. like 100 mph dust devils, and knife edge passes. Ha Ha…….But maybe!?.

Ultracote®™ heat shrink plastic film is the “covering”. This covering has proved to be pretty tough stuff. Bright colors are used to aid in visibility. Mirror light reflecting film will be added to the tips and vertical tails. It can be seen for long distances and creates a great light show at times.

Cleaning off the finger prints and admiring.

Off the bench at last! Day 8 and its almost ready to fly, minor balancing using the battery is still needed. No decals for the first flight….They weren’t ready in time and that was OK by me, it would have meant a late night. The Delta ARF is in the background on the left and Delta 1 Tanker on the right.

Getting the air force to the practice field was fun. 2 more are in the trailer.

May 10, 2003 was “Maiden Day” with Delta II Tanker in the background. The ARF is on the left and was our “prototype.” It was originally fitted with a four stroke OS .91 to prove it was what we needed for the race 3 years ago. (ARF’s come pre-built and are “Almost Ready to Fly” produced by Bruce Tharpe Engineering (800) 557-4470. Now the ARF has a 2 Stoke OS .61 with a pipe. This keeps my adrenalin levels high while flying it for its new owner/team member, Callie. This is her aircraft for training, getting used to the thin profile that can disappear at the right angles and lighting, 3.75″ is the thickest part of the wing.

The smile says it all on Maidening day!! It flys great and doesn’t have any weird characteristics even though it is heavy. Good work Team!!

Now for the getting some practice and perfecting our routine. There never seems to be enough practice time. Springtime is very windy, every year. Especially on the weekends! “Delta 1” is on the left and the new “Delta II Tanker” on the right.

“Signs, Signs, everywhere were Signs!”
Warning! Signs are “model aircraft magnets” on take offs and landings. On our practice outing we managed to avoid all of them……narrowly.

Callie is polishing up during a cross country outing. Callie helps relieve me throughout the race. We need to drink a lot of water in the desert heat and that creates the need for being relieved, which creates another problem of where and how and so on. We don’t stop! Practice on the road was a great success in 2003; winds were gusting to 30, just challenging enough for landing on the 2 lane paved road. We drove about 125 miles south of where we live to get to a perfect place. On a Sunday we saw about 12 cars all day.

On one hair raising, across the road take off at this very spot, in 25 mph winds, I almost strained our practice Delta through a fence. A tremendous amount of pucker power on that one, as it climbed out at 80 degrees vertically, a split second after it left the 21’ wide runway. I think it was just a few feet in front of the fence when it shot straight up. The ARF came home intact and the Antelope were left wondering, “what the ????”

Callie enjoying a ride in the swiveling pilots seat on practice day.

The day before the race at the field for warm up, practice flying and landings.

Laying a dead prop to rest at the prop burial grounds after practice at the VMP Flyers Associations field the day before the race.

Race Day! We were #4 in take off order.
Left to right: James II – Navigator; Callie – Co-Pilot; Henry – Ground Speed Control; Bridey – Up Front Spotter; Jim – Sr Pilot. James II didn’t get to help with the building…although I know he would have enjoyed it very much. We were glad to have him join our team when he did.

Crosswind take off on the last leg. Note the angle of the tall grass at the car door. This photo was taken off the missile range. No Cameras are allowed while on the range.

Pilot to Co-pilot, come in over! Callie at the controls and serious about it.

Touch down on the 6 foot bull’s-eye target for extra points. This photo is the actual time of contact in the center of the bull’s-eye! Thanks for the picture Mario! Callie was on the air brake switch right on key and we dropped it in! Note where Bridey is aiming her camera, she missed it, this was a 40mph “fly it in” landing. There are no other airplanes, just us. I think this was attempt 4 or 5 in front of a crowd of people, after we just flew for 4 hrs in traditional race and pit crew fashion, AND I had to run under and through a shade structure loosing visual for a couple of seconds to get out onto their field. That was their method of entry, not mine! I have safety issues with it for next year. The race is as you might imagine…nerve rackingly fun!

Congratulations we finished!! And its in one piece, Callie helped out a lot! Great Co-Piloting!
Notice the chip on the prop, only one all day, it happened on the final landing and is still flyable.

Our well deserved……Second Place! Team work paid off! The team was really a team, running smoothly. The plane flew very well and proved to be tough enough for the race.
Target time for the entire race, start to finish was 3:27 with 2 mandatory fuel/battery stops and 5 check point stops to retrieve raffle tickets, our time was 4:01. An error on the part of the organizers forgot to allow time for pit stops, so everyone was late by the judges standards. We didn’t catch it until it was too late. First place turned in at 3:34. Chuck Andraka’s team wins every year and he caught the error early on. His math skills are much better than ours. He never practices but is a national fun fly competitor. He has a calculator for a brain and was born with a transmitter in his hand. I really genuinely like the guy and visa versa, we are good friends.

The race was fun, action packed and is now history. The Delta preformed as expected with no mishaps. The first leg was 30 miles, the second 98 miles non-stop for 2 hrs 17 minutes (looks like our absolute range at 80mph is 3.5 hrs) the third and final leg 18 miles. This year was cool at 100 degrees, and again no wind. 70oz. of fuel was consumed on the long leg, we took off with only 90oz. on board (124 oz. capacity) knowing we had a good safety factor calculated in. Our team did very well, taking it from design to the finish line. We all can be so proud of our efforts and major accomplishments. This had never been done before! If they had given a technical achievement award we would have won it hands down. Good Job Team “Delta Drivers!!”

Watching the amazing sunset after the race on the White Sand dunes. We had watched it rise too. The moon was full but the skies were overcast and we couldn’t enjoy it…..we didn’t much care……It had been a full day of fun in the New Mexico sun!

Jim is offering the Ladies a towel they asked for during a cool dip after the HOT race, before dinner. Henry is always ready for photo ops. Neither of them wanted the towel after all.

Alamogordo’s Air & Space Museum up on the side of the mountain. White Sands basin in the background. What a view! This is a great museum for Air and Space enthusiasts!

Special Thanks to these fine folks:

Jim’s Automotive Inc.
4401 Lead Ave SE
Albuquerque, New Mexico 87108

2801 Eubank NE Suite P
Albuquerque, New Mexico 87112 505-293-1217

Bruce Tharpe Engineering-Delta Vortex
(Delta Vortex is Available in Kit or ARF form)
8622 E Evans Creek Rd.
Rogue River, OR 97537
(800) 557-4470
email: [email protected]

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