Our Stearman was manufactured by Boeing 10/21/1943. It was assigned to the Naval Air Station at Ottumwa, Iowa. It spent the entire war there until 6/12/1946 when it was stricken from active duty and designated surplus. Terry Aircraft of Helena, Arkansas purchased the N25-5, Bu Aer No. 43615, and Ser # 75-8709 from W.A.A. for $350. They converted it for AG use by the installation of a P&W R-985 engine. McCarthy Flying Service, West Helena, Arkansas, purchased the Stearman 8/31/1971. Peggy and I purchased it from Riddell Flying Service 7/5/1978.
I had sold my Dragster because the last Drag Strip in Minnesota closed that summer. John Hatz, designer of the Hatz Bi-Plane, flew our Stearman back to Minnesota (I did not have my Flying License yet). John taught me how to fly and checked me out in our Stearman. John and his two sons, Cliff and Al, helped convert the old sprayer and cover the air frame. We kept the P&W R-985 engine and added a prop governor. We didn’t have enough money at that time for the STC’d ServAero engine mount, so we kept the old solid engine mount and Licensed the Stearman in Experimental Exhibition Category.
We flew our Stearman from 1980 until 1985 when we met John Younkin of Historic Aviation, Springdale, Arkansas. This is where our sixteen year Modification Adventure started. We now wanted to completely rebuild our Stearman into Standard Cat. Acrobatic class. We didn’t want it to look like the typical 450 hp Custom Stearman. Jim suggested we modify our airplane into the style of the 1933 Model 80 Stearman with the Warp. Jr. engine.
The following list of modifications resulted in 24 F.A.A. Field Approval 337 forms completed and accepted. They also included the required continuing airworthy maintenance information in each 337 form.
· The ServAero STC’d engine mount was used to install the P&W R-985 The ServAero STC R-985 installation was the basis, with listed Field approved deviations.
· A Hamilton Standard 22030 C.S. prep.
· Fabricated a spun aluminum engine Speed- Ring with P&W engine baffles.
· Twin Beech H Model carb heat box and intake air scoops were modified.
· Jim fabricated a new stainless steel engine dishpan.
· The engine boot cowling was fabricated on Jim’s Power- Hammer and English wheel. Louvers were added for extra engine compartment cooling.
· The new stainless engine firewall was fabricated. The top section of the firewall was lowered 2” to enhance the engine boot cowl appearance.
· A dual out-let stainless exhaust system was modified. It uses an internal tube for supplying hot carb air. This really adds to the clean exhaust system appearance.
· An 8 gal. Aluminum tank was built and installed in the baggage compartment. The engine oil cooler was not installed in the baggage compartment. It was mounted between the landing gear with a hand formed alum. Cowling. This was done to maintain 50% usage of the baggage compartment.
· The landing gear legs were turned around backwards so the gear scissors point to the rear of the aircraft. This eliminates the clearance wheel pants and looks much cleaner.
· Ag-Cat axles and Cleveland disc braker with 10:00 wheels and 8:50 x 10:00 tires were installed. An axle adapter plate was bolted to the stock Stearman Knuckle. This also raised the aircraft 2” over stock height increasing the angle of attack.
· The smaller diameter 8:50 x 10:00 tires allowed us to install copies of the Mr. Mulligan Air Racer wheel pants.
· The center section fuel tank supports were machined to lower the tank into the center section. New top fuel tank straps were fabricated. This allowed a new aluminum tank cover with accent lines to be installed with no fuel tank straps showing.
· External wood stringers were installed on the bottom of the center section instead of stitching the fabric to give the older aircraft appearance.
· An old Lou Liebe C.A.B. approved fuel gauge was installed in the place of the stock unit.
· The Fuselage stringer cage was fabricated with all new shaped formers and only three aluminum stringers, instead of the stock # of eight, to help give the early Stearman slab sided appearance.
- · Flying wire Javelins were changed to solid oak and laced with cord to the Flying wires.
- · All new designed cockpit cowlings with full wrap-around leather combings were installed. Because of the new fuselage shape, the instrument panels were custom made to fit. A headrest and a new baggage compartment door was made.
- · Grimes pedestal mount wing tip lights and tail post lights were used on new custom mounts.
- · The 3 piece landing gear door covers were replaced with a piece cover to help remove the military appearance.
- · The main modification to change the stock military appearance was the addition of the Model- 80 style vertical fin and rudder. A stock vertical fin with the stock tail wire mounts had approx. 5” added to the height. New ¼” tail wires were installed due to the P&W R-985 engine. A fourth rudder-bearing mount was also added. The stock rudder was re-shaped and the extra bearing mount was added. The tail post light mount was added. The re-design of the vertical fin and rudder added 24% more area. This greatly adds to the response at low air speeds and during the landing roll-out.
- · The aircraft was covered with Ceconcite fabric using Randolph dope for build-up. The PPG Durethane II, DGHS paint was applied.
After all the 337’s were completed, filed and approved by the local GATO office; we received the Standard Category – Aerobatic Class air worthiness certificate 8/24/2000!
We have flown the aircraft 62 hours with out any “Bugs”. In 2001 we attended the EAA Oshkosh Fly-in and were awarded Antique Custom Champion. At the Antique Airplane Assoc. fly-in in Blakesburg IA, the modified Stearman received the Classic Champion award.
Peggy and I planned on attending the SRA Fly-in, but the weather God’s did not agree! We plan on attending in 2002. If there are any questions on the modifications or the 337 field approvals please feel free to contact us.