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-   -   COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY (https://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/8096976-comp-arf-110%22-f4u-arf-folding-wing-assembly.html)

samparfitt 07-20-2010 08:07 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Engine.

I mounted the engine so I can locate the best position of the ignition. The cable for the spark plugs isn't very long so it makes placement difficult. I want to be able to mount the engine after the wings are attached to the fuse to remove the 12 lbs of weight and make assembly a little easier (also to reduce the chance of hanger rash). Since the sensor cable only has a connection at the ignition end and no connection in the middle (like the spark plug cable), I'm going to remove the two bolts at the sensor side on the hub of the engine so the engine can be bolted on last.
I made a wood mount for the ignition.
I made two close holes with forstner bits in the fire wall closest to the spark and sensor cables.
It seems best to put the ignition on the opposite side of these two holes in order for the plug cable to easily fit through the hole in the fire wall. I positioned the ignition so the two green LED's will be seen through another hole in the fire wall on the far side. This way, I can visually check if the ignition is working while the cowl if off.

pic 1:
Engine mounted for positioning ignition.

pic 2:
Ignition dry fitted on ply mount where the plug cable can easiest exit the fire wall.
The obvious spot of putting the ignition right in front of the first hole doesn't work as the plug cable connection is so long that it will touch the muffler ring if left on the outside of the firewall.

pic 3:
the spark plug connection is tight but I should be able to detach the two part connector.
They obviously made the plug cable with a center connection so a large hole wasn't needed for the large ignition but it would have been nice if they did the same for the sensor!

pic 4:
Hole in other side of fire wall so I can visually see the ignition's green LED's.

DJ 07-20-2010 10:40 PM

RE: COMP ARF 110
 
1 Attachment(s)
Sam
Couple of shots on my set up for the motor. I have my electronics set up on rubber mounts. On the bottom of the model there are three impressions. One will be for the fuel and the vent. the other I will place a small acrylic window to view the lights if needed.
I found this site for festo fittings, great service, http://shopping.netsuite.com/flightworks

The tail wheel looks great, Six feet off the deck and 100+ MPH and no body will see it,

DJ

samparfitt 07-21-2010 06:05 AM

RE: COMP ARF 110
 
DJ,
Thanks for the pictures and the tip on rubber bushings: I forgot about insulating it from vibration.
I book marked that festo site.
How did you make the hole in the fire wall so small for the sensor wire as both ends are rather large?

didiwatt 07-21-2010 07:59 AM

RE: COMP ARF 110
 
Sam & DJ:

From previous experience, please don't forget to tape or somehow lock the threaded ignition plug when finished. Vibration is just enough for it to unscrew over a few flights. Just for your info.......... looking good guys.

Also, on the tail wheel assembly. On the suspension ram, there is a threaded nut that holds the ram and inner spring into the cylinder. Check to see if the round nut is loose and needs to be locktighted. Mine came off during the 4th flight and I lost the spring. You will see that it is not the best design because you cannot actually tighten it, but I have had no more problems after using some locktite.

DJ, is that fuel line double wrapped around the outer circumfrance of the firewall? I don't get it?

Paul

samparfitt 07-21-2010 09:21 AM

RE: COMP ARF 110
 
1 Attachment(s)
Paul,
thanks for the tips.
I read about taping the spark cable on the 'moki' thread.
Not sure what you are referring to on the round nut on the suspension ram: mine has two T's at each end with button head screws holding it to the frame. The 'air' cylinder looks like an ordinary 'air' cylinder that is flat on each end (I'm assuming that there is a spring in the 'air' cylinder for compression). Mine shouldn't come loose (or at least come apart) as I put an elongated C hook made out of piano wire to slightly compress it as it was too long and not allowing my doors to close.
The cylinder is flat on each end so, maybe, Darrell changed the design.

============
Assembly (cont)

Engine (cont)

I soldered a female connector onto the ignition and connected it to the on/off switch and the 2000 ma, 5 volt battery via a 5.2 volt regulator. I got the regulator from TBM when I bought the engine since they recommend a voltage regulator. Not an expert on batteries but it seems like the AAA battery packs don't go past their max voltage but the C and D's do and I'm using a C battery pack.
A battery tray was also made and epoxied to the top of the fuse next to the ignition tray.
A throttle servo tray was constructed and will be screwed to the inside of the fire wall.

pic 1:
Blind nuts put on the ignition tray.

pic 2:
2000 ma battery pack and 5.2 regulator for the ignition.

pic 3:
ignition and battery trays installed.
Three rubber grommets used on the bottom of each bolt.

pic 4:
throttle servo tray.

samparfitt 07-21-2010 03:39 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Engine (cont)

The throttle and choke assemblies were installed.

pic 1:
A brass tube was put over the threaded 4/40 rod to reduce the chance of the threads from snagging the hole that the rod goes through in the fire wall.

pic 2:
Throttle servo connected to the engine throttle linkage via an easy to connect sliding sleeve ball connector from Sullivan.

pic 3:
Throttle servo tray screwed to the back of the fire wall.

pic 4:
A 1/2" wide hole needed since part of the sullivan ball link goes into the fire wall hole.

pic 5:
Choke set up on fire wall.
A HS-225 servo connected to one side of a dubro #167 90 degree bell crank and the other side via a sullivan ball link.
I needed the bell crank for two reasons:
1) there wasn't room for the servo arm to move freely and be connected to the end of the push rod.
2) I needed to be able to reduce the full servo arm throw down to the small amount of movement needed for the choke linkage. I ran out of channels and work both the choke and cowl flaps with the same channel: The cowl flaps need full servo throw so adjustment of the servo arm throw via the transmitter was not possible. This works out nice as the cowl flaps closed tells me that the choke is closed and vise versa.

pic 6:
choke synced to the cowl flaps.

pic 7:
I don't think my idea of leaving the folding wings on 'in transit' is going to work as they shake pretty easily in the UP position and all that trailer movement probably will damage the mechanism.

pic 8:
My buddy Willis told me about viton tubing that's resistant to the methanol that they put in our vehicle gas (causes the tygon to get hard from the methanol fumes in the tank).
It's not cheap at $3.79 a foot plus tax (company's in Ohio) and shipping made 10 feet cost $45.26.
It'll be worth it if the tank lines stays flexible. I'll use the tygon external to the tank so the 10 feet will go a long way.
http://www.mcmaster.com/#5119k41/=827nmv

DJ 07-21-2010 04:04 PM

RE: COMP ARF 110
 
Paul/Sam
The line is my vent for the tank. I don't like fuel leaking when i'm working around the fueled model.
The holes in the fire wall are cut to just allow the round plug to fit thru. The ground wire? The ends on the fitting come off and are removed then the plug will fit thru. I took a rubber grommet that has a 1/4" wall thickness and cut one flange off. Then split the grommet to go around the wire. They will be bonded in once the model is complete.
The blue shock on my model is an RC car shock that I got from my local hobby dealer. It is assembled with no oil and has spacers in side to correct for the height. It's a much better fit than the stock item that comes with the gear. It works very smooth with no binding or play.
DJ

uncljoe 07-21-2010 04:25 PM

RE: COMP ARF 110
 
pic 7:
I don't think my idea of leaving the folding wings on 'in transit' is going to work as they shake pretty easily in the UP position and all that trailer movement probably will damage the mechanism.

Sam
why not fabercate some kind of jury struts like the full scale, Perhaps even a piece of pink foam that would keep pressure on the wings to spread(wing down) I plan on transporting my U Bird with the wings foladed as its the only way it will fit in the Avalanche
Joe


samparfitt 07-21-2010 06:17 PM

RE: COMP ARF 110
 
Joe,
Good idea: I'll see what I can 'Brainstorm'.
One nice think that I've noticed is that my vehicle bounces less than my trailer so you may have an advantage.

samparfitt 07-21-2010 08:00 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Engine (cont)

I went to HD and bought several 3/4" brass 45 degree elbows, connectors and straight pipe (they wanted 7 bucks for a 2' piece of 3/4" or $15 for a 10' piece: a no brainer, can always use for house plumbing).

pic 1/2:
dry fit with cowl on.

pic 2:
One side needed an extra elbow.
Not exactly scale but it's functional.
The 3/4" ID was a little larger than the mufflers exhaust so I wrapped one layer of some brass sheeting to make up the difference.
Tomorrow, I'll get two hose clamps and solder the rest.
At the Toledo show, I bought some 3/4" flexible pipe but it's too thick and interfered with the cowl flap mechanism.

samparfitt 07-22-2010 09:36 AM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Engine (cont)

I cleaned, fluxed and soldered all the brass tubing and then made a brass strap and soldered it to the brass tubing to hold the exhaust pipe to the engine muffler and against the fuse. The brass fitting is loose where it connects to the engine muffler but I used a hose clamp and spark plug boot protectors to bridge the two mating surfaces and, also, to insulate the tube from the fuse. If this doesn't work, I'll figure 'something else out'.
The brass strap was made so each end tab was a little short of touching where it will be screwed to as this will provide a tight fit.
The spark plug protectors are from my local auto store listed as Handypack, HP2670 and was the perfect fit over the brass tubing. One end had a wire ring which I had to cut and remove.

pic 1/2:
Some hex head servo screws used to hold the strap to the fire wall.

pic 3:
The cowl just misses the brass tubing.

samparfitt 07-22-2010 02:29 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Fuel tank:

I'm using a 50 oz dubro fuel tank.
I'm using the new Viton tubing for the interior of the tank as it's suppose to remain flexible.
The vent line is wrapped around the base of the tank before exiting the fire wall.
A two line system is used with a T fitting from the fill button to the line that goes to the carb.
The tank is located over the CG on the bottom (as viewed from the wing hole in the fuse) of the main tray.

pic 1:
Viton tubing and ferrules soldered to each end of the brass tubing on the clunk side.

pic 2:
50 oz tank.
Vent tubing wrapped around base of tank.

pic 3:
K&S spring set for bending tubing without kinking it.

pic 4:
Main tray with tank on the opposite side of tray.
Heavy nylon wrap put on ignition wires.

pic 5:
Battery pack tray screwed to main tray.
Two 5000 ma packs should be enough (hopefully this provides any additional weight that might be needed for balancing). Since the batteries are hanging upside down once the plane is right side up, I put a large piece of foam against the fire wall to help support the batteries. Any additional weight needed will be put in the bottom front of the fuse.

pic 6:
Engine setup.

pic 7:
Attaching the fuel line to the carb is in a difficult spot so I put an in-line connector for attaching the line after the engine is installed on the fire wall.

pic 8:
Heavy nylon wrap on the ignition wires.
(local auto store)

pic 9:
All parts easily connected/disconnected after engine is mounted.

samparfitt 07-22-2010 06:57 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Cockpit.

The Dbalsa cockpit was built many moons ago so all I have to do is install it.
Everything is made to be removable for access to the back via the wing hole (if necessary).

pic 1:
A three piece 1/8" thick balsa floor was screwed to the triangular stock on each side of the fuse using hex head servo screws. Three pieces were necessary to insert the floor into a very confined area.

pic 2:
More triangular stock epoxied along the back of the cockpit for the back bulkhead.

pic 3:
1/4"X1/2" stock epoxied along the sides for securing the side panels.

pic 4/5:
Side panels and back bulkhead screwed on using #1X1/4 screws.

pic 6:
Triangular stock epoxied to floor to hold side control panels.
Breaks in panels since the floor is in three pieces and may need to be removed in the future.

pic 7/8:
Side control panels secured to the triangular stock.

pic 9:
Instrument panel inserted from the bottom.
It fits so tightly that I didn't use any screws (for now!).
The green panel (represents the back of the prototype fuel tank) was also inserted from the bottom.
I ran one remote to the cockpit so I can visually know if my receivers are working.

pic 10:
The green panel was secured using hex head servo screws.

samparfitt 07-22-2010 07:46 PM

RE: COMP ARF 110
 
1 Attachment(s)
Assembly (cont)

Cockpit (cont)

The control stick has a ply base so I just cut a hole in the floor, put the ply base up from the bottom and screwed the foot rails and control stick base all at once.

pic 1:
Foot rails and control stick installed.

pic 2-5:
Now to decide if I should use a Jimmy Dolittle pilot or a 1/4 scale pilot.
Dolittle looks better and has more detail but is small (he was short anyway) whereas the 1/4 scale is light but not much detail. Guess, I'll paint the dude up and then compare but I'll probably go with Jimmy.

pic 6:
Gun site dry fitted.

Thunderbolt47 07-22-2010 09:11 PM

RE: COMP ARF 110
 
Go with the 1/4 scale.

uncljoe 07-22-2010 09:30 PM

RE: COMP ARF 110
 
Sam
Go with one of these 1/4 scale guy .you won't be disappointed .
www.premierpilots.net/ -
Semper Fi

samparfitt 07-23-2010 05:27 AM

RE: COMP ARF 110
 
those premier dudes are nice.

BobH 07-23-2010 11:49 AM

RE: COMP ARF 110
 
Sam, ya Jimmy was short 5'5" but hes way to small for your 1/4 plane!

uncljoe 07-23-2010 12:04 PM

RE: COMP ARF 110
 
Sam
The only thing that Premier pilots lack is a may west. I used the may west from a blue box pilot(jimmy's will work) It will be short but looks ok to me. One could make one out of yellow cloth .
Semper Fi

DJ 07-23-2010 11:08 PM

RE: COMP ARF 110
 
Sam
I placed an order for one of the pilots, premier pilots. These guys are at my local hobby shop and I should get one pretty quickly. Once I have it I will add a Picture. I will check with them to get the may west made for us.
DJ

uncljoe 07-24-2010 09:38 AM

RE: COMP ARF 110
 
DJ
If they do make the maywests let me know as I'm using one from a Bluebox figure,
Joe

DJ 07-24-2010 09:50 AM

RE: COMP ARF 110
 
1 Attachment(s)
Joe
Will Do, Out flying today TF 1/5 scale P-51 DA 50 kelo exhaust. absolute blast to rip up the sky with. I'll get with the shop after the flying session

DJ

MarkShapiro 07-24-2010 05:05 PM

RE: COMP ARF 110
 
Sam, the brass exhaust tubing looks great, but you must braze it on rather than silver solder. The heat of the running engine and exhaust through the pipes will absolutely unsolder them. Trust me on this.

samparfitt 07-24-2010 05:10 PM

RE: COMP ARF 110
 
Mark,
Thanks:now all I have to do find out what brazing is!
I heard that JB weld works well on exhausts: it will be difficult to unsolder these joints: I'll probably just buy new ones and JB all the connections.

Thunderbolt47 07-24-2010 06:06 PM

RE: COMP ARF 110
 
Sam, I don't think JB weld will hold the heat of a gas engine.


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