Cold Duck - Build
06-20-2005, 08:32 PM
#1
Cold Duck - Build
Years ago there was a 60 size 650 sq in pattern aircraft design called the “Cold Duck”. It was very sleek, super light (six pounds with retracts) and fast! And that was six pounds loaded down with old heavy PCS radio gear and giant KPS9 servos. I built one in 1969 and really liked it but it met its end in a mid air with a Kaos in the early 70s. After all these years I decided it was time to build another and I still have my plans from the June 1971 RC Modeler Magazine. The original design was a tail dragger with main gear retracts because in 69 retracts were a pretty risky proposition and two of them was more than enough trouble. The new “Cold Duck” will have trike gear! My original was powered by an old Veco 61 but the new one will have a powerful and modern 61.
Some images of the original circa 1970.
Some images of the original circa 1970.
06-21-2005, 08:12 AM
#2
RE: Cold Duck - Build
I’ve ordered the balsa needed to build the Cold Duck from Dynamic Balsa ( http://www.dbalsa.com/ ) and also the foam wing core. Everything was in stock so I should have the order in a few days. Meanwhile, I started building the horizontal and vertical stab. I’m using my vintage, tattered and yellowed RCM plans but new Cold Duck plans are still available from the RC Modeler Magazine plan service at http://www.rcmmagazine.com/e/env/000...ore-plans.html plan number 462.
The horizontal stab is built typical of the “Classics” using a ¼ balsa frame and covered with 1/16 balsa sheeting. I’m using the very lightest balsa available.
View of the old plans and the horizontal stab progress.
The horizontal stab is built typical of the “Classics” using a ¼ balsa frame and covered with 1/16 balsa sheeting. I’m using the very lightest balsa available.
View of the old plans and the horizontal stab progress.
06-23-2005, 03:05 PM
#6
RE: Cold Duck - Build
View of the tail parts with the bass wood trailing edges installed and more shaping work completed. The elevators and rudder have been tapered down to the 1/8” X 1/16” trailing edge.
The original Cold Duck had ailerons that were added to the wing trailing edge similar to the way the Kaos ailerons were designed. The new Cold Duck will have ailerons that are a continuation of the airfoil shape like my Howard Engineering Kwik Fli III taper wing has. To that end, I ordered a set of Howard Engineering Kwik Fli III taper wing ailerons and they can be seen at the top of the image. They are 1 ½” wide and will have 1/8” X1/16” bass wood trailing edge added. I should have my Dynamic Balsa shipment soon with my balsa and foam wing core.
The original Cold Duck had ailerons that were added to the wing trailing edge similar to the way the Kaos ailerons were designed. The new Cold Duck will have ailerons that are a continuation of the airfoil shape like my Howard Engineering Kwik Fli III taper wing has. To that end, I ordered a set of Howard Engineering Kwik Fli III taper wing ailerons and they can be seen at the top of the image. They are 1 ½” wide and will have 1/8” X1/16” bass wood trailing edge added. I should have my Dynamic Balsa shipment soon with my balsa and foam wing core.
06-25-2005, 10:09 AM
#10
RE: Cold Duck - Build
View of the nose ring, Dave Brown (50-60) engine mount, fire wall, fuselage formers, and front former doubler. The wing will have a ¼” plywood tongue that will fit into the square opening in the front fuselage former like is used on the Howard Engineering kits. I’m moving the firewall back ½” to make more room for the longer engine. The old Veco 61 that the Cold Duck was designed around was pretty short.
My Dynamic Balsa order shipped last Friday so it should arrive next week with my balsa supply and foam wing core. I also ordered a canopy, aileron linkage, Dave Brown Southern Sorghum foam wing glue and a Goldberg 2” white spinner from Tower. The 10 ¼’ Great Planes canopy is shorter than what I wanted but canopy choices are pretty limited now-a-days.
My Dynamic Balsa order shipped last Friday so it should arrive next week with my balsa supply and foam wing core. I also ordered a canopy, aileron linkage, Dave Brown Southern Sorghum foam wing glue and a Goldberg 2” white spinner from Tower. The 10 ¼’ Great Planes canopy is shorter than what I wanted but canopy choices are pretty limited now-a-days.
06-26-2005, 10:41 AM
#13
RE: Cold Duck - Build
I like to complete the setup of the engine mount, fuel tank and nose gear steering before the firewall is installed. It is a lot easer to drill holes and mount stuff with the firewall on the bench. Many years of building Howard Engineering kits has influenced the way I build, so I’ll be borrowing his well engineered fuel tank mounting system for the Cold Duck. See my Howard Engineering Kwik Fli III build on RCU at http://www.rcuniverse.com/forum/m_2434444/tm.htm
A plywood plate is made for the front of the fuel tank that bolts to the firewall with blind nuts. It is a really neat system and keeps the fuel lines from getting kinked and makes tank installation and removal easy. I’m using the specified Sullivan RST-12 fuel tank.
I decided to mount the engine less than the original 90 degrees for a little more muffler clearance.
A plywood plate is made for the front of the fuel tank that bolts to the firewall with blind nuts. It is a really neat system and keeps the fuel lines from getting kinked and makes tank installation and removal easy. I’m using the specified Sullivan RST-12 fuel tank.
I decided to mount the engine less than the original 90 degrees for a little more muffler clearance.
06-28-2005, 08:39 AM
#15
RE: Cold Duck - Build
View of the completed vertical and horizontal stab with hinges and elevator joiner wire test fit. The Du-bro standard hinges are counter sunk into the stabs and control surfaces to create a zero gap hinge line. The leading edge of the control surfaces are beveled with a sharp edge at the hinge line to provide the sealing point. This eliminates the need for unsightly sealing tape on the hinge lines. The shaping and sanding work on the stabs is almost complete. I increased the span of the horizontal stab 3 1/2” and the width of the elevators ½”. This change increases the wing/stab percentage from 20% to 25%.
The main gear mounting blocks have short hardwood dowels epoxied to the backside and the blocks drilled for the landing gear struts.
My Dynamic Balsa shipment with my balsa supplies and foam core should be delivered later today.
The main gear mounting blocks have short hardwood dowels epoxied to the backside and the blocks drilled for the landing gear struts.
My Dynamic Balsa shipment with my balsa supplies and foam core should be delivered later today.
06-29-2005, 02:31 PM
#16
RE: Cold Duck - Build
My Dynamic Balsa shipment with my balsa supplies and foam core arrived yesterday.
From the left to right:
4 - 1/2 X 1/2 X 48 triangle stock – fuselage corners.
2 – 1/8 X 2 X 36 – lower fuselage side doublers.
2 - 1/8 X 4 X 48 – fuselage sides.
1 – 1/2 X 4 X 48 – fuselage top
2 – 1/4 X 2 X 36 – wing leading edge.
1 – 1/4 X 4 X 36 – fuselage bottom.
12 - 1/16 X 4 X 36 – wing skins.
1- Cold Duck foam wing core set at the top. Very nicely cut and smooth.
I have another parts order on its way from Tower with the 2” spinner, aileron linkage, Orange MonoKote, etc and it should be arriving later this week.
From the left to right:
4 - 1/2 X 1/2 X 48 triangle stock – fuselage corners.
2 – 1/8 X 2 X 36 – lower fuselage side doublers.
2 - 1/8 X 4 X 48 – fuselage sides.
1 – 1/2 X 4 X 48 – fuselage top
2 – 1/4 X 2 X 36 – wing leading edge.
1 – 1/4 X 4 X 36 – fuselage bottom.
12 - 1/16 X 4 X 36 – wing skins.
1- Cold Duck foam wing core set at the top. Very nicely cut and smooth.
I have another parts order on its way from Tower with the 2” spinner, aileron linkage, Orange MonoKote, etc and it should be arriving later this week.
07-02-2005, 02:38 PM
#18
RE: Cold Duck - Build
My Tower parts order arrived with the following:
2” Goldberg spinier
1” X 3” X 12” Balsa block for wing tips
Canopy glue.
Dave Brown foam wing contact cement.
A few new Futaba ball bearing servos.
Canopy.
Goldberg push rods
4-40 cap bolts for elevator and rudder control.
Elevator and rudder control brackets.
Aileron linkage.
Landing gear straps.
Wheels
More Du-bro standard hinges.
MonoKote (Orange)
2” Goldberg spinier
1” X 3” X 12” Balsa block for wing tips
Canopy glue.
Dave Brown foam wing contact cement.
A few new Futaba ball bearing servos.
Canopy.
Goldberg push rods
4-40 cap bolts for elevator and rudder control.
Elevator and rudder control brackets.
Aileron linkage.
Landing gear straps.
Wheels
More Du-bro standard hinges.
MonoKote (Orange)
07-09-2005, 03:07 PM
#21
RE: Cold Duck - Build
Decided that I didn’t like the mounting system used on the new Futaba S3004 ball bearing servos so I sent them back and went with the S3001 ball bearing units. The S3001 servos share the same foot print and mounting system used on my S148 standard servos and on my S3151 and S9252 digital servos. I also ordered a new nose gear to replace the one used for test fitting. It has a longer lower area below the coil and I will be using an adjustable axel.
07-11-2005, 02:14 PM
#22
RE: Cold Duck - Build
The fuselage formers and firewall are glued on to the ½” thick balsa fuselage top. Epoxy was used on the firewall. A center line is scribed down the center of the fuselage top for aligning the center of the formers. It is very important to make sure the formers are glued on square to the center line and the fuselage top. I relocated the firewall back about 1/2” to make more room for the modern engine that is longer than the old original Veco 61. A hole was drilled in the firewall for the throttle cable before mounting the firewall.
I also made the fuselage ½” narrower because the modern servos are so much smaller. No other airframe modifications are planned.
I also made the fuselage ½” narrower because the modern servos are so much smaller. No other airframe modifications are planned.
07-12-2005, 07:56 PM
#23
RE: Cold Duck - Build
View of the fuselage side with the doubler and top corner glued on and test fitting the fuselage sides to the fuselage top. Scrap balsa sticks are temporally glued to the former edges to keep them square with the fuselage top.
