Volume XI No. 4 Page 40 1990
RYAN ST-A - Byron Originals
By Irv Allison IMAA 820
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During August, 1989 I had the opportunity to attend the Byron Originals Festival in Ida Grove, IA. This is truly a show which must be seen to be believed. However, one of the main events at the festival for me was my first glimpse of the Ryan ST-A that Byron was about to release. I had to build that Ryan.
When the kit arrived, I found it to be packed in the excellent manner that I have come to expect from all Byron kits. The kit is very complete with fiberglass fuselage, cowl and pants plus the wings and tail of injection molded foam. The kit also has many vacuum molded parts down to wing strut covers, instrument panel and cockpit seats. And we must not forget the large foam pad that is common in many Byron kits, so you can line your workbench and protect your Ryan during assembly. Mylar markings for the PT-22and an instruction manual complete the kit.
This 28 page instruction hook with its 99 photographs and the separate large exploded assembly views, combine for a very clear set of building guides. Just be sure you understand the instructions completely before going through each of the assembly steps and you will have no trouble at all.
The fuselage goes together very easily. The bulkheads
are die cut and they fit with no trimming required at all. The only
thing to he careful of is the tailwheel. Be sure that it is installed
correctly and everything is tight at the time you build it in.
When you add the rudder, it all becomes quite inaccessible.
The wings are plug in panels. The flap drive also plugs
in as a part of the wing panel. This makes for really fast and easy
field set up. There are two flap sizes shown in the plans. I opted
for the shorter flap, making more room for a larger aileron and
better response in the air. If you follow the instructions, you
will cover the wings and tail with a low temperature iron on
covering. This should work fine and look great. After all, the
ribs in the wings and stab are molded right in for the appearance
of built up structures. However, I decided to he different at this
point.
I have found that the greatest natural enemy to foam wing or tail structures is a door frame. I always seem to end up with dings and dents in the foam edges of stabs, rudders and wings. My solution is to edge these surfaces with balsa. This lining helps protect the foam and adds very little weight. The wings already have a balsa trailing edge, so I had to treat the tips and leading edges only. I cut the wing leading edge back 3/8" and the tips 1/4". The tail outline was trimmed by 1/4". I then added a 1/8" flat strip along the wing leading edge. This was to help anchor 3/32 x 3" top and bottom cap strips which were attached with 3M 77 contact cement. A 1/4" thick strip then completed the leading edge. The wing tips and the tail outline have 4 strips of 1/16" balsa, soaked in water, spread with white glue and bent around the foam. These strips were held in place with rubber bands until the glue dried. Rib caps of 3/32 x 1/4" were then added over the molded rib outlines in the wing. Some sanding finished off the job. After covering, the wing has the appearance of being a built up structure.
The receiver and servos mount under the back seat with the receiver battery just aft of the rear seat. I am using a CH Electronics ignition system on the Supertigre 3000 engine and the ignition battery plus the ignition box are mounted just behind the firewall. This arrangement balanced the plane with no extra weights required. Instruments and a Knights of the Air pilot then completed the interior.
The ST-3000 engine was modified slightly with the addition of an OS 1.08 carburetor. This carburetor is an exact fit replacement and gives me 1,000 additional RPM with no change in either the prop or fuel. Since I am not using a pump on the engine, I did not remove the venturi that comes installed in the carburetor.
Finishing the Ryan involved several different techniques. I first went over the fuselage, cowl and pants for any pin holes. The tail surfaces, flaps and ailerons were fiberglass using Dan Parsons' lightweight cloth and epoxy system. Remember that these parts are foam and that a polyester resin will melt foam. The wing was covered with Supershrink Coverite. I use an iron for both application and shrinking with a Coverite thermometer for setting the temperature. Set the iron shrink temperature as high as possible without melting the fabric.
Rib stitching was simulated using small pieces of nylon fishing line under Scotch brand Hair Set tape. The plane was primed with R-M Hydrosol automotive water based acrylic primer. The finish coat is Rust-oleum thinned 15% with mineral spirits. I am sure that most modelers will choose to finish their Ryan in the PT-22 color scheme. However, I chose the more colorful (flamboyant?) scheme of a civilian craft.
I have to admit to some concern before the first flights. I was bothered with the location of the CG. I am no aeronautical engineer and the balance point seemed to be somewhat further back than other kits I have built. I was therefore delighted to meet Ken Bundt at the Oshkosh IMAA Festival because it gave me the chance to ask the man who was the Project Engineer on the Ryan. He assured me that the balance point was correct - and of course, he was right.
My Ryan flies better than I had ever hoped. It is not a trainer, but it would be a good choice as the second plane after getting into giant size. This plane is faster than I expected, but it slows down easily for landings with no snap tendency at all. The Ryan just wallows around without snapping when flown at altitude while holding full up elevator. Rolls come out very axial with aileron inputs only and very little down elevator is required for inverted flight. I have found landings to be predictable and easy, both with and without flaps. And takeoffs are much easier than I expected after looking at the narrow appearing gear tread.
I ran into only one problem with my Ryan. There is a brass tube about 1" long which connects the top and bottom portions of the landing gear strut and is located about 1" above the axle. I had heard that this tube can bend very easily when a heavy load is applied usually during landing. And it does. Only mine happened on a takeoff from grass. The run appeared straight, but in correcting for torque, I probably caused the tires to skid on the grass. Then hitting a small grass clump caused a bend from the sideload resulting in the tire rubbing on the strut. My talk with Ken Bundt in Oshkosh had revealed Byron is already aware of the problem and that all future kits will have a strengthened gear.
However, for those of us with the earlier kits, the fix is simplicity itself. Put the strut in a vise and pull one end of the strut out of the brass tube. A little heat helps here as Locktite was applied to help hold the strut in the tube. And take it easy with the heat. Then cut a piece of brass tube 1 1/2" long of the next size up and slip over the existing tube with some 1 hour epoxy between the tubes. Complete the job by roughing up the strut some, where it goes back into the tubing, apply some epoxy and slip the strut back into the tube. Be sure to align the strut correctly. Both of the gear struts on my Ryan have held up fine ever since this simple fix.
I am very happy with my Ryan both in the air and on the ground. It is an absolute delight to fly and it has certainly been a center of attention whenever shown. I think that both Mr. Godberson and Mr. Bundt can he justifiably proud of this offering.
Specifications:
Name: Ryan ST-A Manufacturer: Byron Originals, P.O. Box 279, Ida Grove, Iowa 51445 Phone 712-364-3165 List Price: $439.95 plus $10.00 S&H Span: 90" Cord: 14" Area: 8.75 Sq. Ft. Weight: 19 lbs. Wing Loading: 34. 7 0 ./Sq. Ft. Length: 66" Height: 20" Engine: Supertigre 3000 Carburetor: OS 1.08 Ignition: CH Electronics Box 1732 Riverton, WY 82501 Phone 307-857-6897 Fuel: Byron Supertigre Blend Propeller: Dynathrust: 18 x 10 Spinner: Tru Turn P.O. Box 836 South Houston, TX 77587 Phone 713-943-1867 Covering: Coverite Supershrink Fiberglass: Dan Parsons Primer: R-1lf Hydrosol Gray Paint: Rust-oleum Radio: Futabu 7 Channel PC37 Flight Photos: Al Priez