Spark Ignition Viking

Since we don’t see too many spark ignitions planes here on SSW, I’d like to show my restored Viking. It was scratchbuilt many years ago and after quite a few flights, it showed considerable aging. The covering had become extremely brittle so I decided to do a total refinish, along with removing some weight.
The OK Super 60, which I modified, has powered it from day one and, after some teething problems, has not been touched in over 300 flights. It was replaced exactly as removed.
The finish is silk with Randolph’s and Aero-gloss dope.
It now weighs less than 46 ounces with everything but fuel – it has a 2-ounce tank.
The ignition is as designed back in the 50’s – nothing is transistorized. The only “modern” touch is NiMH batteries.
It’s a lot of fun to fly but extremely loud. I hope to someday engineer a muffler for it.

Bob Z

That is flat out cool!

It surely is cool!!!! How long does it run on 2 ounces of fuel? Are you using gas/oil or methanol/oil?

Hi, Steve - thanks for the reply.
The two-ounce tank is adequate for the OTS or classic pattern. It usually runs around 6 1/2 to 7 minutes.
I use only regular gasoline and castor oil in all my ignition engines. I've found that combination to produce the best and cleanest runs and there has never been a lubrication-related problem.
I know that a number of people use methanol/castor oil with good results but, it would require approximately 6 ounces - as you can see, there is no room for a larger tank in the Viking.
Bob Z

I forgot to ask in my first response....where is the timer arm??

Bob Z. Your VIKING/OK-60 is really nice. You might know that I champion spark ignition OTS planes. I would like to see more photo examples printed in STUNT NEWS.

To all: The OK60 has the timer in the rear of the engine, so the spark advance arm would normally be on the right side of the fuselage. An adjustable spark timer is convenient for hand-starting, but it can be locked in the advance position if you use an electric starter. Early speed models, using McCoy, Dooling, and Hornet engines usually had the timer locked in full advance because starting a speed model was always done with a mechanical inertia (flywheel) starter device.

Floyd and Steve - now it's getting more interesting! Steve, the timer is, as Floyd pointed out, at the rear of the engine. It can be indexed at 120 degree increments to position the arm wherever is convenient. I positioned mine to exit at the bottom of the fuselage. I also keep it locked at full advance, which is controlled by a cast lug on the backplate. It's so easy starting that I rarely move it. By the way, the moving point from a 1967 ALFA Romeo is an exact replacement on the OK .60!
Bob Z
I will soon post a picture of my other ignition plane.

LAST EDITED ON May-21-04 AT 01:35 PM (CDT)
 
Wow, not much room in that fuse, nice job with the equipment layout. Perfect pilot choice also

C/B: The reason for the short fuselage is that the plane is so light that with the engine and all the support equipment, I needed to add 2 ounces to the tail. So, I moved the engine back by one motor mount pitch and sacrificed some volume.
I wonder if I could put the batteries inside the pilot?
Bob Z

That is a really nice airplane. Do you suppose it is the first Viking ever to be flown with an ignition engine?

Nope - the second one!

>Bob Z. Your VIKING/OK-60 is really nice. You might know
>that I champion spark ignition OTS planes. I would like to
>see more photo examples printed in STUNT NEWS.
>
>To all: The OK60 has the timer in the rear of the engine,
>so the spark advance arm would normally be on the right side
>of the fuselage. An adjustable spark timer is convenient
>for hand-starting, but it can be locked in the advance
>position if you use an electric starter. Early speed
>models, using McCoy, Dooling, and Hornet engines usually had
>the timer locked in full advance because starting a speed
>model was always done with a mechanical inertia (flywheel)
>starter device.
>
>Floyd

Ron B.
F4Fguy

I always hand started mine.Stand way back and SWAT!!!! 1st time 'most every time!(of course you had to expect the occasional broken prop)

Hi Bob
Show everyone the pictures of your Fury Screwball. Guys if you think that the Viking is stunning you should see what Bob accomplished with his rendition of that model.
It is without doubt one of the most marvellous pieces of model making skills I have seen. Truly a work of art in both design and execution.
Detachable wings, empennage and undercarriage via a single cam in the fuse! a beautiful silk covering job and an ignition installation as compact as the Viking.
Just as good as it gets.
Cheers John Goodwin

>Since we don’t see too many spark ignitions planes here on
>SSW, I’d like to show my restored Viking. It was
>scratchbuilt many years ago and after quite a few flights,
>it showed considerable aging. The covering had become
>extremely brittle so I decided to do a total refinish, along
>with removing some weight.
>The OK Super 60, which I modified, has powered it from day
>one and, after some teething problems, has not been touched
>in over 300 flights. It was replaced exactly as removed.
>The finish is silk with Randolph’s and Aero-gloss dope.
>It now weighs less than 46 ounces with everything but fuel –
>it has a 2-ounce tank.
>The ignition is as designed back in the 50’s – nothing is
>transistorized. The only “modern” touch is NiMH batteries.
>It’s a lot of fun to fly but extremely loud. I hope to
>someday engineer a muffler for it.
>
>Bob Z

Ron B.
F4Fguy

Bob:

Brings back a lot of memories.How do you keep it from shaking itself to pieces?I never could keep my Zilch together.Of course that could have been poor assembly skills t that time!

Ron B. If your plane shakes, it is the engine! Many old tyme engines were not well balanced. Examples are the O&R 60, and the Bunch Tigers. Probably more. There are engine gurus out there who will balance your Old Time engine. Names that come to me are, George Tallent, Don Blackburn, and maybe more.