Oriental ARF

[petermick]

Last month I asked for suggestions about what I could fly at the 2013 VSC.  My initial inclination was to build a Ringmaster. Most of the comments I received were negative on that idea.  Following a number of suggestions my leaning was in the direction of a Magician.  Fortunately for me I was able to purchase from a fellow contestant at the Sugar Grove contest an in the box Brodak Oriental ARF he had won as a raffle prize. The Oriental ARF was a good choice as a fellow member of the Milwaukee Circlemasters had recently built and trimmed the same plane.  I therefore had the luxury of learning the pros and cons of the assembly of the Oriental ARF before I made the same mistakes.

The following is a small list of the changes that were made to my plane based on the observations made by my fellow club member.

1) For whatever reason the motor mounts on many ARFs seem to be cheaply made and are prone to crushing when the motor mount bolts are tightened down.  To overcome this I put aluminum motor pads on the nut side of the mounts.  This is intended to spread out the pressure of the tightened nuts against the mount.  I also put brass bushings in the motor mount holes. I drilled out the mounting holes one size larger than is necessary for a 4-40 bolt. The brass bushing are slightly shorter that the overall length of the hole. This is intended to eliminate crushing from the engine side of the motor mount.

2) The mounting for the landing gear seemed to be flimsy.  The directions indicated the use of three wood screws to attach the aluminum gear.  I substituted blind nuts and 4-40 bolts to attach the gear.

3) My engine of choice is an OS FP 40.  This engine is a little heavier that the Brodak 40 so I used a tongue muffler and I epoxied 2 ounces of lead weight into the aft section of the fuselage.  Prior to final assembly I found the plane balanced just forward of the spar
with all parts either bolted on of taped on.

Yesterday the plane had its initial flights.  Much to my surprise I was able to do the full pattern on its second flight without doing any trimming other than slight adjustments to the handle spacing. 

Here are the planes spec.

Weight               45 oz
Engine               OS FP 40
Prop                  Brodak BYO 10/5
Line length         58 feet
Fuel                   SIG 5% Nitro  20% Castor
Fuel Tank           Brodak 4 oz Uniflow 
Lap Speed          4.5 Seconds
Flight time          6 minutes 15 seconds

Conclusions.  This is one of the most enjoyable planes I have ever flown in spite of the fast lap speed. I will go to longer lines (62 or 64 feet) to slow down the lap speed.  I may need to go to a larger tank to accommodate more fuel at VSC where I may need to use 10% nitro.  The only trim adjustments I need to make are a trim tab to overcome a slightly high outboard wing tip and an additional amount of tip weight.

Peter Mick
AMA 9581

[john e. holliday]

I too loved my Oriental ARF until I had about 30 flights on it.  Power was Brodak .40.  The plane was acting funny at Denver the year I tried to fly it there.   Found the wing was coming loose from the fuse.  Came home and stripped the plane down and cut into the top.   Not only was there not enough gluing surface, but the link to the flap horn from the bellcrank had a lot of slop in it from use.  While I had it open I put in ball links to tighten every thing up and put in glass cloth and resin inside the fuse to wing joint.  Recovered the plane.  It never flew the same and I could not figure out what was wrong.  Maybe it got too heavy.  But, I gave it to young man that wanted to learn to fly stunt.  It was a great flying plane when new.