The vertical fin has been attached the fuse which again is very straight forward.
Friday, January 23, 2009
Tow Mechanism Point
As I'm planning to use my Pawnee as a tug, the tow release point has to be of suitable construction to be able to take the loads of towing gliders.
As with other Pawnee tugs that I've seen I've chosen the location just behind the cockpit, which lines up with F5 on the plan. I discarded the laser cut F5 made from 4mm balsa, and made another one from 6mm birch ply.
I've also constructed a triangular brace from the same material and will epoxy this in place to strength the tow point.
Toying around with the idea ot using carbon tubes to brace F5 instead of the ply, any ideas welcome.
You can also see in the pictures the actual tow point which is milled from aluminium, with a 2-56 rod coming up the centre to hold the tow rope in place. A servo will be installed underneath F5 to acuate this rod.

As with other Pawnee tugs that I've seen I've chosen the location just behind the cockpit, which lines up with F5 on the plan. I discarded the laser cut F5 made from 4mm balsa, and made another one from 6mm birch ply.
I've also constructed a triangular brace from the same material and will epoxy this in place to strength the tow point.
Toying around with the idea ot using carbon tubes to brace F5 instead of the ply, any ideas welcome.
You can also see in the pictures the actual tow point which is milled from aluminium, with a 2-56 rod coming up the centre to hold the tow rope in place. A servo will be installed underneath F5 to acuate this rod.
Horizontal Stab
The construction of the Horizontal stab is pretty straight forward. Again as with the fin the "tricky" parts that would previously have required steaming and bending have been CNC cut in the TMRC kit and also notched to take the spruce. Making construction a simple and straight forward process.
You'll be sick of cutting gussets though by the end of it! :)
The elevator is constructed in the same fashion. Un sure at this stage if I will use a single servo for the elevator as Tom has done on the plans, or if I'll use two.
You'll be sick of cutting gussets though by the end of it! :)
The elevator is constructed in the same fashion. Un sure at this stage if I will use a single servo for the elevator as Tom has done on the plans, or if I'll use two.
Thursday, January 8, 2009
New Coreflute Racer (Tea Racer)
I spent some time over the holidays knocking up a new coreflute (same stuff real estate signs are made out of) racer. It's called the "Tea Racer" and is designed by the Mugi guys. (http://www.mugi.co.uk)
Takes a 28mm inrunner, and with a 1800-2000kV short can (48mm) brushless and a 6x5 prop you can tear up the sky. I run mine on 3S 2200mAH and it's great fun. I made two of these, and my brother and I have had a blast racing around the place.
Checkout the website and make one, it costs about $15 for a sheet of coreflute, and a couple of bucks for some servo's and a receiver, the only expensive stuff is the motor, speedy and lipo, and you really shouldn't skimp on a good speedy, and a good lipo, balancer and charger.
Vertical Fin and Rudder Construction
Firewall / Tank Compartment + Stringers
Well I've managed to get back out to the shed over the holidays and do a few nights work attaching the firewall, tank compartment, and stringers at the front. I've also added the formers on the rear deck to start the aft of the fuse.
Currently working on the towing attachment point which will sit at the first of the aft formers but obviously re-enforced with carbon tube, and ply.
During the assembly of the firewall etc, the CNC cutting made for the ply sides in no way whatsoever matched up with anything resembling a fit for the propost 4deg of down thrust as required by the plans, so we've had to notch up the firewall to fit them properly.
The warp has been removed during this process quite simply by adding the strings and ensuring that the whole assemble was straight and square before finalising everything.
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