Details of giant-scale Constellation project - lengthy post
05-20-2003, 01:49 PM
#1
Thread Starter
Details of giant-scale Constellation project - lengthy post
Hi everyone,
A number of RCU readers have inquired about the details of the large Constellation model appearing in my avatar and photo gallery. In this post I have attempted to answer many of those questions, and perhaps include a few more details. At any rate, for those who have several spare minutes and an interest in a model of a prop airliner from the past, read on.
It is a 1/10th scale copy of a Model 1049 (stretched fuselage) Constellation, or “Connie”. The Connie is considered by many aviation buffs as the most glamorous and beautiful of the multi-engine prop airliners. This version is minus the tip tanks, which are used on the Model 1649 “Starliner” version.
The current owner of the aircraft is Tom Kondzior of CT. Tom and I became friends after he attended my radio-control flight school back in 1990. At that time, Tom discussed his dream plane with his fellow r/c club members, and some of them had tried to discourage him from even attempting to build such a plane.
Little did they know how tenacious Tom could be. I told Tom that it WAS possible to scratch-build such a detailed flying model, but it would be difficult and expensive. So, he decided it was worth a shot, and asked if I could assist if needed. I agreed. This was Tom’s first "real" model: he had only built ONE foam R/C plane (a Cessna ARF) previously.
Tom and another modeler, Nick Champaign, cut and assembled the fuse formers (rings), framed a wing, and tail section. It was actually started before 1991, and was originally going to be an ALUMINUM airplane! After a scale tail section (horiz. stab) came out at 11 lbs., it was decided to go with different materials. This is where I was called in as a consultant and builder/designer. After deciding aluminum was NOT a practical way to go, we re-designed the wing, tail, and body center. So, foam, balsa, pine, spruce, and fiberglass became the prime components, with aluminum remaining in some areas (spars, center section, nacelle tubes, etc). No full-size plans were available then, so we mathematically scaled up a plan from a plastic model kit, and supplemented it with data & photos from the real bird. We never drew any full-size prints . . . only a bunch of conversions, pencil sketches, and notes.
The wingspan is 11 ft., 3 in., with overall fuse length at 10 ft. 2 in. The horizontal stabilizer measures 4 ft. 5 in. All-up weight is estimated closely to be a whopping 70 lbs. An unusual departure: the wing is one piece, and is permanently mounted to the fuse center. The 24” nose section, and the 48” tail section remove for transport, and are tied in to the fuselage's plywood frame rings, connected with load-dispersing brass tubes and metal tabs, all secured with flush bolts and steel lock pins for flight operations.
Mains (retracts) are electric worm-gear type, by Likes Line of PA (replacing scratch-built ones which may have been too weak). The nose gear is still a scratch-built unit, but will be replaced with a Likes unit. Gear doors are servo-driven, using a Jomar Gear-Door Sequencer. There are 19 servos on board (all optically isolated), driven by two, nine-channel McDaniel buffer amps, and powered with heavy-duty 22 Ga. wire. The elevator uses a special Futaba servo ($ 175.00 in 1991) with about 11 ft. lbs. of torque, and this servo has it's own battery. All servos are sized according to loads imposed. Braking is going to be by Glennis Aircraft UAV brakes, capable of stopping a 90 lb. plane safely in under 100 ft. They are air-operated, using air to release them (via servo control), and will activate without lockup if air pressure drops. Glennis is also supplying specs for scale tires. wheels, and strut ornamentation details, to be added after test flights.
Landing lights are four halogen bulbs in two servo-operated, swing-down housings, normally retracted in the bottom of the wing. Navigation lights and beacons are also in scale locations and operational. There are six battery systems on board, with redundant switches/ batteries for the receiver. Power switching for each system is via redundant slide switches, double-pole, for reliability. A low-battery alarm is also on board for the receiver, as well as a lost plane alarm (hopefully never needed). Every servo has a removable link (series) to monitor current draw and drive the servo externally: test functions are accessed from the nose gear compartment, and all electrical functions are monitored or tested there. Each servo's load is measured and recorded for test purposes, using a custom-made digital servo driver. Servos are connected by Deans connectors, except for the Futaba receiver ends. All wiring is labeled & coded to a schematic diagram.
The airplane has a full interior, with seating (cut and stained foam & balsa), overhead lighting, luggage compartments, bathroom doors, curtains, simulated carpeting, and floor mats. There are two scale operating sliding doors to allow interior viewing. Outside air is ducted into the fuselage to slightly pressurize the interior, helping to prevent the cabin windows from popping inward during flight.
There is NOTHING visible inside the completed plane which reveals it to be an r/c model . . . no batteries, linkages, wires, or servos. Everything used for control is hidden under the floors, in the ceiling, walls, wings, etc. This was a major point in the design criteria, and has been a constant challenge. Only when the nose and tail are removed can the complicated electrical and linkage systems become visible.
The cockpit (although virtually invisible), has a scale back-lit instrument panel, seats, and control yokes. There are even two mini-speakers installed under the floor in the main cabin, which pipe 1950's era music in the plane when parked (and connected to a recorder) hidden in a scale 1959 Mack fuel truck which will actually fuel the plane and supplies ground power for display.
Engine servos are NOT synchronized (on the advice of many top scale modelers) and instead will be carefully broken in and tested in a test aircraft, then set conservatively as not to flame out. This is aided by a McDaniel 4-engine onboard glow driver system, which keeps the plugs hot on takeoff and landing, with an auxiliary switch channel in case of problems when cruising. The flaps are driven by a scratch-built torque tube system, bearing supported, using Fowler simulated hinges and a unique multi-arm rack and track mechanism. Ailerons, rudders, & elevators are balanced, bearing supported and removable. Hinge fairings cover the hinge gaps and reduce gap turbulence to near zero, and increase control efficiency. Flaps flush-mount into the wing.
This aircraft also boasts having NO externally visible R/C linkages or control rod hardware . . . EVERYTHING is hidden inside the structure. Yet, all rudders, ailerons, flaps, & elevator halves are removable for service and inspection. A total of 22 removable access hatches allow service to every operating feature of the aircraft. The outer surface is covered in 3/4 oz. glass cloth & epoxy, and will be painted in a former Eastern Airlines scheme. The wing chord is 34 inches at the root, and uses a combination of four NACA airfoils out to the tips, with washout and reflexed aileron positions to help prevent tip stall. And, the two outboard rudders feature differential movement (via internal linkages in the horiz. stab) to prevent compression and turbulence between the vertical tail sections when turning.
Four flat-style fuel tanks are in the wing, two in each wing half (inboard of the inside engines), each holding 16 oz. of fuel.
Power is supplied by four O.S. 120 Surpass II four-cycle engines, mounted inverted, with fuel pumps. Fuel overflow and venting is via simulated pitot tubes below each tank hatch, and fuel inlets are Dubro Quik-Fueler valves, flush-mounted behind each engine on top of the wing, with custom-made caps. Engine nacelles are made of .050" thick, riveted aircraft aluminum sheeting, framed internally, and wrapped in a balsa/glass skin. Cowls are preformed (fiberglass), with dummy radial engines visible. Props are Graupner 15-6, three-blade scale jobs, which were recommended by both O.S. and Graupner (after phone calls and letters to their engineers in Germany and Japan). An aluminum blade spar was machined for us (at Pratt & Whitney Aircraft), and runs vertically behind all four engines. We load-tested this spar with over 450 lbs. without a hint of failure, by two of us actually walking barefoot on the wings! (I weighed in at 320 lbs., and Tom weighs about 150 lbs.). Radio control will be by a Futaba 9-channel PCM system, and a live video downlink is being considered.
I have drawn a full electrical schematic, plus fuel system and air hookup diagrams for the plane. We also have prepared checklists for preflight and postflight inspections, engine & battery performance and maintenance, and emergency procedures.
The aircraft is calculated to have a 115 mph cruise speed, with a 45 mph stall. We have built four custom-fitted foam & plywood transport/setup cradles. We consulted with former Connie pilots, flight engineers, and aeronautical designers in the process of building the plane. Flight testing will be done at a full-scale airport which will be closed to regular air traffic while we are present. If possible, we are going to wind-tunnel test it before actual flights.
We have lost track of the hours involved in design & construction, but it well exceeds 1,500 hours. And, we have been invited to display and/or fly the aircraft in over fourteen states so far, including taking it on tour (actually flying inside a full-size Connie), with the Save-A-Connie group in Kansas City, MO.
Finally, the total cost of this plane now exceeds $ 18,000.00 !
Not your ordinary R/C model !
Al Parry
[email protected]
A number of RCU readers have inquired about the details of the large Constellation model appearing in my avatar and photo gallery. In this post I have attempted to answer many of those questions, and perhaps include a few more details. At any rate, for those who have several spare minutes and an interest in a model of a prop airliner from the past, read on.
It is a 1/10th scale copy of a Model 1049 (stretched fuselage) Constellation, or “Connie”. The Connie is considered by many aviation buffs as the most glamorous and beautiful of the multi-engine prop airliners. This version is minus the tip tanks, which are used on the Model 1649 “Starliner” version.
The current owner of the aircraft is Tom Kondzior of CT. Tom and I became friends after he attended my radio-control flight school back in 1990. At that time, Tom discussed his dream plane with his fellow r/c club members, and some of them had tried to discourage him from even attempting to build such a plane.
Little did they know how tenacious Tom could be. I told Tom that it WAS possible to scratch-build such a detailed flying model, but it would be difficult and expensive. So, he decided it was worth a shot, and asked if I could assist if needed. I agreed. This was Tom’s first "real" model: he had only built ONE foam R/C plane (a Cessna ARF) previously.
Tom and another modeler, Nick Champaign, cut and assembled the fuse formers (rings), framed a wing, and tail section. It was actually started before 1991, and was originally going to be an ALUMINUM airplane! After a scale tail section (horiz. stab) came out at 11 lbs., it was decided to go with different materials. This is where I was called in as a consultant and builder/designer. After deciding aluminum was NOT a practical way to go, we re-designed the wing, tail, and body center. So, foam, balsa, pine, spruce, and fiberglass became the prime components, with aluminum remaining in some areas (spars, center section, nacelle tubes, etc). No full-size plans were available then, so we mathematically scaled up a plan from a plastic model kit, and supplemented it with data & photos from the real bird. We never drew any full-size prints . . . only a bunch of conversions, pencil sketches, and notes.
The wingspan is 11 ft., 3 in., with overall fuse length at 10 ft. 2 in. The horizontal stabilizer measures 4 ft. 5 in. All-up weight is estimated closely to be a whopping 70 lbs. An unusual departure: the wing is one piece, and is permanently mounted to the fuse center. The 24” nose section, and the 48” tail section remove for transport, and are tied in to the fuselage's plywood frame rings, connected with load-dispersing brass tubes and metal tabs, all secured with flush bolts and steel lock pins for flight operations.
Mains (retracts) are electric worm-gear type, by Likes Line of PA (replacing scratch-built ones which may have been too weak). The nose gear is still a scratch-built unit, but will be replaced with a Likes unit. Gear doors are servo-driven, using a Jomar Gear-Door Sequencer. There are 19 servos on board (all optically isolated), driven by two, nine-channel McDaniel buffer amps, and powered with heavy-duty 22 Ga. wire. The elevator uses a special Futaba servo ($ 175.00 in 1991) with about 11 ft. lbs. of torque, and this servo has it's own battery. All servos are sized according to loads imposed. Braking is going to be by Glennis Aircraft UAV brakes, capable of stopping a 90 lb. plane safely in under 100 ft. They are air-operated, using air to release them (via servo control), and will activate without lockup if air pressure drops. Glennis is also supplying specs for scale tires. wheels, and strut ornamentation details, to be added after test flights.
Landing lights are four halogen bulbs in two servo-operated, swing-down housings, normally retracted in the bottom of the wing. Navigation lights and beacons are also in scale locations and operational. There are six battery systems on board, with redundant switches/ batteries for the receiver. Power switching for each system is via redundant slide switches, double-pole, for reliability. A low-battery alarm is also on board for the receiver, as well as a lost plane alarm (hopefully never needed). Every servo has a removable link (series) to monitor current draw and drive the servo externally: test functions are accessed from the nose gear compartment, and all electrical functions are monitored or tested there. Each servo's load is measured and recorded for test purposes, using a custom-made digital servo driver. Servos are connected by Deans connectors, except for the Futaba receiver ends. All wiring is labeled & coded to a schematic diagram.
The airplane has a full interior, with seating (cut and stained foam & balsa), overhead lighting, luggage compartments, bathroom doors, curtains, simulated carpeting, and floor mats. There are two scale operating sliding doors to allow interior viewing. Outside air is ducted into the fuselage to slightly pressurize the interior, helping to prevent the cabin windows from popping inward during flight.
There is NOTHING visible inside the completed plane which reveals it to be an r/c model . . . no batteries, linkages, wires, or servos. Everything used for control is hidden under the floors, in the ceiling, walls, wings, etc. This was a major point in the design criteria, and has been a constant challenge. Only when the nose and tail are removed can the complicated electrical and linkage systems become visible.
The cockpit (although virtually invisible), has a scale back-lit instrument panel, seats, and control yokes. There are even two mini-speakers installed under the floor in the main cabin, which pipe 1950's era music in the plane when parked (and connected to a recorder) hidden in a scale 1959 Mack fuel truck which will actually fuel the plane and supplies ground power for display.
Engine servos are NOT synchronized (on the advice of many top scale modelers) and instead will be carefully broken in and tested in a test aircraft, then set conservatively as not to flame out. This is aided by a McDaniel 4-engine onboard glow driver system, which keeps the plugs hot on takeoff and landing, with an auxiliary switch channel in case of problems when cruising. The flaps are driven by a scratch-built torque tube system, bearing supported, using Fowler simulated hinges and a unique multi-arm rack and track mechanism. Ailerons, rudders, & elevators are balanced, bearing supported and removable. Hinge fairings cover the hinge gaps and reduce gap turbulence to near zero, and increase control efficiency. Flaps flush-mount into the wing.
This aircraft also boasts having NO externally visible R/C linkages or control rod hardware . . . EVERYTHING is hidden inside the structure. Yet, all rudders, ailerons, flaps, & elevator halves are removable for service and inspection. A total of 22 removable access hatches allow service to every operating feature of the aircraft. The outer surface is covered in 3/4 oz. glass cloth & epoxy, and will be painted in a former Eastern Airlines scheme. The wing chord is 34 inches at the root, and uses a combination of four NACA airfoils out to the tips, with washout and reflexed aileron positions to help prevent tip stall. And, the two outboard rudders feature differential movement (via internal linkages in the horiz. stab) to prevent compression and turbulence between the vertical tail sections when turning.
Four flat-style fuel tanks are in the wing, two in each wing half (inboard of the inside engines), each holding 16 oz. of fuel.
Power is supplied by four O.S. 120 Surpass II four-cycle engines, mounted inverted, with fuel pumps. Fuel overflow and venting is via simulated pitot tubes below each tank hatch, and fuel inlets are Dubro Quik-Fueler valves, flush-mounted behind each engine on top of the wing, with custom-made caps. Engine nacelles are made of .050" thick, riveted aircraft aluminum sheeting, framed internally, and wrapped in a balsa/glass skin. Cowls are preformed (fiberglass), with dummy radial engines visible. Props are Graupner 15-6, three-blade scale jobs, which were recommended by both O.S. and Graupner (after phone calls and letters to their engineers in Germany and Japan). An aluminum blade spar was machined for us (at Pratt & Whitney Aircraft), and runs vertically behind all four engines. We load-tested this spar with over 450 lbs. without a hint of failure, by two of us actually walking barefoot on the wings! (I weighed in at 320 lbs., and Tom weighs about 150 lbs.). Radio control will be by a Futaba 9-channel PCM system, and a live video downlink is being considered.
I have drawn a full electrical schematic, plus fuel system and air hookup diagrams for the plane. We also have prepared checklists for preflight and postflight inspections, engine & battery performance and maintenance, and emergency procedures.
The aircraft is calculated to have a 115 mph cruise speed, with a 45 mph stall. We have built four custom-fitted foam & plywood transport/setup cradles. We consulted with former Connie pilots, flight engineers, and aeronautical designers in the process of building the plane. Flight testing will be done at a full-scale airport which will be closed to regular air traffic while we are present. If possible, we are going to wind-tunnel test it before actual flights.
We have lost track of the hours involved in design & construction, but it well exceeds 1,500 hours. And, we have been invited to display and/or fly the aircraft in over fourteen states so far, including taking it on tour (actually flying inside a full-size Connie), with the Save-A-Connie group in Kansas City, MO.
Finally, the total cost of this plane now exceeds $ 18,000.00 !
Not your ordinary R/C model !
Al Parry
[email protected]
05-20-2003, 03:37 PM
#4
Thread Starter
Details of giant-scale Constellation project - lengthy post
There are some black & white photos of the Connie in my Photo Gallery here on RCU, and in the Giant -scale photo section. I have others which show some of the construction processes, but have not posted those as yet.
Regards,
Al
[email protected]
Regards,
Al
[email protected]
05-20-2003, 06:07 PM
#5
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Re: Details of giant-scale Constellation project - lengthy post
Originally posted by Eaglewatch
Props are Graupner 15-6, three-blade scale jobs, which were recommended by both O.S. and Graupner (after phone calls and letters to their engineers in Germany and Japan).
The aircraft is calculated to have a 115 mph cruise speed, with a 45 mph stall.
Props are Graupner 15-6, three-blade scale jobs, which were recommended by both O.S. and Graupner (after phone calls and letters to their engineers in Germany and Japan).
The aircraft is calculated to have a 115 mph cruise speed, with a 45 mph stall.
05-20-2003, 07:14 PM
#6
Thread Starter
Details of giant-scale Constellation project - lengthy post
Hi,
Wells, you make a valid point regarding performance of these props on the O.S. 120 Surpass engines.
The prop choice I mentioned was made quite some time ago, based on conversations between the owner, Graupner, and O.S..
Since that time, some changes have no doubt occured in prop availability and engine power. We do have the 15-6 props, which were obtained several years ago. If I recall correctly, these were the props to be used initially during the break-in period, and may not reflect what is really needed for "safe" flight. Each engine will undergo a break-in period in another aircraft (a single-engine model) to determine it's performance parameters (including prop size variation effects). Only after break-in and performance issues are satisfied will the engines be installed on the Connie.
We are now considering the possibility of using more powerful engines, since the weight of the plane is higher than originally planned.
Regards,
Al Parry
[email protected]
Wells, you make a valid point regarding performance of these props on the O.S. 120 Surpass engines.
The prop choice I mentioned was made quite some time ago, based on conversations between the owner, Graupner, and O.S..
Since that time, some changes have no doubt occured in prop availability and engine power. We do have the 15-6 props, which were obtained several years ago. If I recall correctly, these were the props to be used initially during the break-in period, and may not reflect what is really needed for "safe" flight. Each engine will undergo a break-in period in another aircraft (a single-engine model) to determine it's performance parameters (including prop size variation effects). Only after break-in and performance issues are satisfied will the engines be installed on the Connie.
We are now considering the possibility of using more powerful engines, since the weight of the plane is higher than originally planned.
Regards,
Al Parry
[email protected]
05-10-2004, 10:29 PM
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RE: Details of giant-scale Constellation project - lengthy post
As incredibly sophisticated as this plane is (probably the most intricate and realistic RC plane ever), I'm surprised it doesn't have radial engines as the real one did. Of course, four compound, supercharged radial engines would probably be hard to come by.
