RC Guys Cherokee 140 Revamp
#1
Thread Starter
RC Guys Cherokee 140 Revamp
Well I plan to document my very first ARFbuild. Oh I have put together several for friends, but this is mine. Times are changing, I can't believe Ijust said that. My intentions thus far are strip and recover with different scheme, Robarts struts, D&B 3.7 twin, different linkage (Possibility hidden), wheel pants. Rather than go into great detail I plan to focus on the deviations from the instructions. You can download the manual on the RC Guy site, was too large to attach.
#2
Thread Starter
RE: RC Guys Cherokee 140 Revamp
Since there are many unknows here I dry fit the engine box together and held with #2 servo screws. It took minor sanding to get everything together. The box is also held in with servo screws.
#3
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The instructions have you install several wood blocks on the firewall to screw the cowl on. I perfer the cowl ring method. In this case 6 number 6-32 screws will be accessible from the the interior. The ring is 1/8" liteply, 1/8" aircraft doublersat the blind nuts. The
#5
Thread Starter
RE: RC Guys Cherokee 140 Revamp
I used this extension device to locate the front of cowl to the enginecenterline while gluing in the ring.
A mixture of microfibers and West Systems epoxy was applied to the inside of the cowl. The cowl was taped into position and the edge was wrapped with and Ace bandage while epoxy set
A mixture of microfibers and West Systems epoxy was applied to the inside of the cowl. The cowl was taped into position and the edge was wrapped with and Ace bandage while epoxy set
#6
Thread Starter
RE: RC Guys Cherokee 140 Revamp
I hope to end up with this engine, D&B 3.7. Initial fitting indicates spark plug interference. I may end up replacing the CM=6 plugs with Rimfire plugs. Time will tell.
#7
My Feedback: (11)
RE: RC Guys Cherokee 140 Revamp
I built one of those for Fly RC magazine, they fly very well. They have the wrong overlap on the covering on the tail so you need to get the edges sealed very well, and throw away the z-bends and replace them with ball links, you might get away with the flaps and ailerons but you definately want to fix the elevator linkage, the flying stab will make anything over half throttle an adventure with a zbend on the elevator.
Oh yea, if you're going to use anything that requires a 22" prop, make sure you move the nose gear before you mount the firewall
Oh yea, if you're going to use anything that requires a 22" prop, make sure you move the nose gear before you mount the firewall
#10
RE: RC Guys Cherokee 140 Revamp
Guys,
I am in the process of completing the RC Guys Super Decathlon. Lots of mods/improvements throughout that thread to the base aircraft. I have gone much heavier Dubro hardware on all the control surfaces. The customer support from RC guys is second to none as Dan Spears is very responsive and also checks the posts regarding his aircraft often.
This looks like an interesting aircraft.
Paul
I am in the process of completing the RC Guys Super Decathlon. Lots of mods/improvements throughout that thread to the base aircraft. I have gone much heavier Dubro hardware on all the control surfaces. The customer support from RC guys is second to none as Dan Spears is very responsive and also checks the posts regarding his aircraft often.
This looks like an interesting aircraft.
Paul
#11
Thread Starter
RE: RC Guys Cherokee 140 Revamp
Just got back from Key West Fla after a week vacation so it is back to work. Thankfully no huricane chased us out.
The motor required 7/8" spacer, this was made from 3/4" X 3/4" blocks cut to 5/8" long with 1/4" aircraft ply firewall. The sides are also 1/4" ply, blind nuts are installed in the original fiewall the the assembly is epoxied together.
#12
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The nose wheel was stuck and required dissassembly to get things moving, looks like the grease dried up and got hard. The machine work leaves a little to be desired so I do plan the replace the strut with a Robart unit. I will retain the stock bracket and make a bushing for the smaller (1/2" diameter) Robart Unit.
#13
Thread Starter
RE: RC Guys Cherokee 140 Revamp
It took no more than 5 minutes to remove the covering from the rudder. Not stuck down very well, I was happy about that. Once the covering was off, inspection shown that the balsa was sanded to almost nothing in several areas. You can see for yourself in the photos. Since this thing is getting re-worked anyway, I just took it all off.
I plan to build and install a Rotary Drive System on the rudder and Ailerons. After adding a few lightening holes, I drilled the rudder post at 45 degree angle for the drive shaft. The servo will be mounted on the bottom side of the rudder assembly.
I plan to build and install a Rotary Drive System on the rudder and Ailerons. After adding a few lightening holes, I drilled the rudder post at 45 degree angle for the drive shaft. The servo will be mounted on the bottom side of the rudder assembly.
#14
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The rudder Rotary Drive consists of a ServoCity (www.servocity.com/html/servo_to_shaft_couplers.html) shaft coupler for the Hitec 7955 servo, 5/32" drive shaft, and 1/8" steel 45 degree bend. The bend is soldered into the 5/32" tube. The servo is mounted on the underside of the rudder platform. Future access to the servo will require covering removal.
The pocket for the rudder was made from Formica sides and 1/8" AC plywood spacer superglued together. The pocket is glued into the rudder with Poly glue. Here is more detail augiemckibben.tripod.com/sitebuildercontent/sitebuilderfiles/making_pockets.pdf
The pocket for the rudder was made from Formica sides and 1/8" AC plywood spacer superglued together. The pocket is glued into the rudder with Poly glue. Here is more detail augiemckibben.tripod.com/sitebuildercontent/sitebuilderfiles/making_pockets.pdf
#15
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The rudder is glued on and the turtle deck sheeting removed. I am strip planking the turtle deck. The orignal was sheeted with full size sheets of what appeared to be very light balsa. I hate to waste light balsa here, a few ounces will not matter to this bird.
#17
Thread Starter
RE: RC Guys Cherokee 140 Revamp
Work continues on the fuselage. Again the radius between side and bottom were made out of contest weight balsa. However the balsa didn't provide sfficient strength to resist the covering tension. The sheeting was removed and replaced 1/2" balsa triangle stock and 3/32" balsa sheeting. This was carved and sanded to final shape. I did manage to save the back half of the original sheeting.
#18
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The joint at the trailing edge of the stablizer fit poorly together. I sanded the joints and installed 1/8" lite ply plates. I plan to make the tail removable, the 1/2" carbon fiber tube will get epoxied into the left side. The trailing edge has a 3/16" dowel installed. The right side will get a 4-40 screw through the tube. Should a mishap occur, the tail can removed for repairs. The holes for the dowel were drilled with the jig that was made from scrap wood. I had to dig deep to locate a Rocket City control horn for the stablizer. It is a shame this company was lost to fire, their hardware was second to none. The screw is a 8-32. I had to enlarge the hole as the stock had 6-32 threads.
#19
Thread Starter
RE: RC Guys Cherokee 140 Revamp
As luck would have it the exhaust and nose wheel want to occupy the same space. The tubes are 5/8" OD so a couple of 45 degree copper street elbows did the trick. I silver soldered 4-40 nuts to elbows and drilled through and tapped, a 4-40 screw will hold the elbow in place along with HT silcone. This will be final fit once I get the Robart struts in hand. I need to figure out how I will vent the cooling from the cowl. Location of the nose wheel and exhaust areknow, now I need to louver the cowl.
#20
Thread Starter
RE: RC Guys Cherokee 140 Revamp
On to the wings. It took about 10 minutes to remove the covering from one wing. When I got to the wing tip I discovered that it was firerglass and not balsa as I had assumed. The best I could tell the tip was painted after it was glued on but before the covering was installed. I would rather wrap the covering around a corner instead of hoping the 3/8" strip of glue will hold the covering in place. I decided to remove the tip for this reason. I made a rib out of 1/4" liteply to screw the tip in place.
Once the covering was removed I found the trailing edge was broke. I plan to span the failure area with carbon fiber laminate. I broke right where you would expect. I wonder how many are flying with this? The top of the spar extends into the adjacent bay while the bottom is butt glued between the alieron and flap .
Robart 670Main struts and 674 Nose strutare on order. The 674 is fixed, I plan to adapt to original bearing block. More on that later.
By the way the flush cut saw is a great tool to use when sawing a joint apart. Harbor Freight sells them
#21
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The landing slot was cut deeper with the Dremel routing attachment and 1/4" ball burr. This was done to hide the wire. Next the landing gear plate was inset to accept a 1/16" plate to give it a scale like look. Once I receive the Robart Struts, the end of the wire will be trimmed off.
#23
Thread Starter
RE: RC Guys Cherokee 140 Revamp
ORIGINAL: gene6029
Nice work! I'm following along since i'm interested in a Cherokee this size myself. Keep up the good work....Gene
Nice work! I'm following along since i'm interested in a Cherokee this size myself. Keep up the good work....Gene
The Rotary Drive for the aileron is near complete,again the Servo City coupler is used to drive the shaft. The mounting plate is 1/8" lite ply stiffened with a balsa stick on the top, the bottom is glued the original plywood mounting plate and accessable throught the cover.
#24
Thread Starter
RE: RC Guys Cherokee 140 Revamp
For the flap linkageI useda heavy duty DuBro rod end. I glued a 1/8" plywood plate onto the stock 2 mm thick horn. This filled the space for the DuBro rod end. The link is made from 3/16" heavy wall K&S aluminum tube taped for 4-40 ends.
For the servo end I made new hatch covers and used Servo City www.servocity.com/html/90_degree_universal.htmlmounts. The mounts are screwed to the cover with 4-40 button head screws. While the original would work fine, I like mine better. It took 1/16" and 1/64" plywood to get the right 2mm thickness.
For the servo end I made new hatch covers and used Servo City www.servocity.com/html/90_degree_universal.htmlmounts. The mounts are screwed to the cover with 4-40 button head screws. While the original would work fine, I like mine better. It took 1/16" and 1/64" plywood to get the right 2mm thickness.
#25
Thread Starter
RE: RC Guys Cherokee 140 Revamp
The Robart struts are here, good job for the upcoming weekend. Need to order the wheel pants. The mains are quite traditional while the nose has the funky trailing edge, I hope to modify a standard pant rather than make single unit. These are photos of full scale units from Ebay.