Hai-Lee
Old and Bold RC PILOT
I had a need for a test bed vehicle for my flying wing project and so I chose the venerable Tiny Trainer.
As the wing span increased the idea of hand launching test flights became a little fraught with danger and increased risk of overcontrolling disasters so I needed an undercarriage. For ground handling I needed steering and as I had no tail a steerable wheel was required.
I built a powerpod version with a steerable nose wheel and so I will post herein how I made it work. The CHALLENGE for the readers or FT themselves is to make a better design or to tidy up the original and even perhaps post their own version.
Here goes!!!!!
For those who are seeking something a little different for the Mighty Minis apart from hand launching, here is a little prototype design for a steerable power pod for use in minis requiring a tricycle undercarriage with steering like the Aerocobra and similar projects.
This is the picture of the very first design and I will not bore the readers with motor details or repeating the power pod manufacture except to state at the outset the power pod is lengthened in my prototype so that the battery can still be fitted under the power pod with velcro as I and others have been doing for years.
The project/build for this thread is the second prototype based closely upon the first with a few minor changes to improve it and make it easier to build and more robust.
Firstly make a standard power pod but make the length 92mm for the longest dimension, (remember the right thrust angle), or as close as you can make it and still have it fit into your fleet of Minis.
Before fitting the Firewall remove a 15mm length of the bottom adjacent to the firewall, and also trim the top FB side rails behind the Firewall 10mm to a depth of the ply thickness you are using, nominally 3mm.
Make a bottom wheel support plate and a top wheel support plate to suit the removed foam from the power pod and glue in position. Allow for the right thrust angle of course, unless you are using shims to obtain the required angles. (I used Epoxy).
When glue is dry/set attach the firewall as per normal ensuring that the thrust angles are still the same as specified for the standard power pod. Ignore thrust angles if using shims. (The motor I used is slightly oversize in its mount so my firewall is slightly larger than standard).
Select wheel leg, (I bent a bicycle spoke as I wanted it to be easily bent in the case of impact), and drill a hole, (of the leg diameter), in both the top and bottom wheel support plates centrally across the powerpod but only 5mm from the firewall.
Select a wheel collar to suit the wheel leg and sand or file to remove plating on one of the flat sides and using a piece of sheet brass or similar, (I used a metal battery contact from an old toy), cut and clean an arm to be soldered to the top of the prepared wheel collar. When soldered and cooled drill a hole in the brass arm to take a small linkage stopper. Fit the linkage stopper.
Fit a second wheel collar or similar device onto the wheel leg and then slide the wheel leg into the bottom hole in the plywood, through the collar with the soldered brass and linkage stopper assembly, (solder to the top of the power pod), and then through the hole in the plywood fitted in the top of the power pod.
With the wheel leg top flush with the upper surface of the upper plywood piece slide the lower wheel collar into contact with the lower plywood and tighten in position. Then slide the modified wheel collar down against the bottom plywood piece and set the horn at an angle of around 15 degrees from sideways across the powerpod. Tighten the modified collar in position.
Fit 3.7 gram servo into rear of powerpod as shown in pic with the servo arm, (when centralised), parallel to the brass horn soldered onto the modified wheel collar. (Use hotmelt glue to secure servo).
Fit motor and ESC into the power pod and have the ESC leads for the receiver and the battery exiting at the rear of the power pod adjacent to the servo. When fitting Bamboo skewers they should run under the ESC flush with the top surface of the power pod bottom.
Fit steering link to the servo arm, Hole with shortest moment, and measure to get proper length and trim. Fit onto servo and into linkage stopper and secure.
Check range of servo and wheel movement and reduce channel rate or end points to give suitable range of wheel movement without servo binding or reaching the mechanical limits of the installation, (Reverse the servo if required to give proper directional response).
The test bed vehicle with the powerpod fitted and functional!
So there it is!
I await the methods and designs of others!
Have fun!
As the wing span increased the idea of hand launching test flights became a little fraught with danger and increased risk of overcontrolling disasters so I needed an undercarriage. For ground handling I needed steering and as I had no tail a steerable wheel was required.
I built a powerpod version with a steerable nose wheel and so I will post herein how I made it work. The CHALLENGE for the readers or FT themselves is to make a better design or to tidy up the original and even perhaps post their own version.
Here goes!!!!!
For those who are seeking something a little different for the Mighty Minis apart from hand launching, here is a little prototype design for a steerable power pod for use in minis requiring a tricycle undercarriage with steering like the Aerocobra and similar projects.
This is the picture of the very first design and I will not bore the readers with motor details or repeating the power pod manufacture except to state at the outset the power pod is lengthened in my prototype so that the battery can still be fitted under the power pod with velcro as I and others have been doing for years.
The project/build for this thread is the second prototype based closely upon the first with a few minor changes to improve it and make it easier to build and more robust.
Firstly make a standard power pod but make the length 92mm for the longest dimension, (remember the right thrust angle), or as close as you can make it and still have it fit into your fleet of Minis.
Before fitting the Firewall remove a 15mm length of the bottom adjacent to the firewall, and also trim the top FB side rails behind the Firewall 10mm to a depth of the ply thickness you are using, nominally 3mm.
Make a bottom wheel support plate and a top wheel support plate to suit the removed foam from the power pod and glue in position. Allow for the right thrust angle of course, unless you are using shims to obtain the required angles. (I used Epoxy).
When glue is dry/set attach the firewall as per normal ensuring that the thrust angles are still the same as specified for the standard power pod. Ignore thrust angles if using shims. (The motor I used is slightly oversize in its mount so my firewall is slightly larger than standard).
Select wheel leg, (I bent a bicycle spoke as I wanted it to be easily bent in the case of impact), and drill a hole, (of the leg diameter), in both the top and bottom wheel support plates centrally across the powerpod but only 5mm from the firewall.
Select a wheel collar to suit the wheel leg and sand or file to remove plating on one of the flat sides and using a piece of sheet brass or similar, (I used a metal battery contact from an old toy), cut and clean an arm to be soldered to the top of the prepared wheel collar. When soldered and cooled drill a hole in the brass arm to take a small linkage stopper. Fit the linkage stopper.
Fit a second wheel collar or similar device onto the wheel leg and then slide the wheel leg into the bottom hole in the plywood, through the collar with the soldered brass and linkage stopper assembly, (solder to the top of the power pod), and then through the hole in the plywood fitted in the top of the power pod.
With the wheel leg top flush with the upper surface of the upper plywood piece slide the lower wheel collar into contact with the lower plywood and tighten in position. Then slide the modified wheel collar down against the bottom plywood piece and set the horn at an angle of around 15 degrees from sideways across the powerpod. Tighten the modified collar in position.
Fit 3.7 gram servo into rear of powerpod as shown in pic with the servo arm, (when centralised), parallel to the brass horn soldered onto the modified wheel collar. (Use hotmelt glue to secure servo).
Fit motor and ESC into the power pod and have the ESC leads for the receiver and the battery exiting at the rear of the power pod adjacent to the servo. When fitting Bamboo skewers they should run under the ESC flush with the top surface of the power pod bottom.
Fit steering link to the servo arm, Hole with shortest moment, and measure to get proper length and trim. Fit onto servo and into linkage stopper and secure.
Check range of servo and wheel movement and reduce channel rate or end points to give suitable range of wheel movement without servo binding or reaching the mechanical limits of the installation, (Reverse the servo if required to give proper directional response).
The test bed vehicle with the powerpod fitted and functional!
So there it is!
I await the methods and designs of others!
Have fun!
