I have always been a big fan of biplanes; just something about them that is enticing. Watching the FF Gotha Gaggle unfold was a real treat, especially with the "skins" that Stephen ( Rasterize) designed for them. The only thing missing was the biplanes. I started to design a Sopwith Camel, but decided that a better initial design/build would be the PT-17. The goal was to make it as scale as possible, with out being overly complex.
MM size PT-17 Stearman
FT Power Pack F
CG = 1 3/4" from leading edge of top wing
MM size PT-17 Plans
MM PT-17 Plans ( full) MM PT-17 Stearman Plans (tiled)
40" PT-17 Stearman
FT Power Pack C
CG = 2 3/4" from leading edge of top wing
Flying weight = 31oz
40" PT-17 Plans ( Updated )
40" PT-17 Stearman fuselage ( Full ) 40" PT-17 Stearman fuselage ( tiled)
40" PT-17 Wings ( full) 40" PT-17 Stearman wings ( tiled )
40" PT-17 Poasterboard ( full) 40" PT-17 Stearman Posterboard (tiled)
40" PT-17 Stearman maiden flight
Twins :-)
The MM size appealed to me with the 24" wingspan, so that is what I started with. It took a couple of modifications to get it to fly the way it should. Slight scale variances were made, but unless you really know the aircraft, you would not even notice them.
The MM size PT-17 is made out of two sheets of foam board, poster board, and skewers. I opted to add the landing gear and wheels for scale appearence sake. Because of the heavy radial engine on the full scale, additional wieght in the nose is needed to get the correct CG.
I would clasify the MM size PT-17 as an intermediate build and flyer. It floats rather well, but does have a definent stall point. Because of the short wingspan it is very nimble. I used the FT "F" power pack on it . This gives it ample power for scale flying.
Here are some build sequence photos with descriptions.
Top wing built, Bottom wing ready to assemble.
Fuselage and tail assembly built, bottom wing attached.
Top wing ready to be attached. ( Note the wing guides that set the proper distance and incidence.)
Top wing and power pod installed. Power pod angle is specific to this aircraft.
"Dummy" engine and landing gear installed. Ready for maiden flight.
Maiden flight
After building the MM size PT-17 and successfully flying, I decided to enlarge the plane to a 40" wingspan. The build progressed relatively well and with surprisingly scale flying characteristics, it is a very stable flyer. The large wing area enables the aircraft to float really well. No extra weight was needed as the battery provides the correct weight/ CG. I would classify the large-scale build as intermediate and a beginners second plane to fly.
Here are some build sequence photos with descriptions.
Fuselage assembled with covering. ( I later removed the covering on the top side as it is covered with posterboard.)
Lower wing assembled and covered.
Power pod inserted, as well as horizantal stabilizer installed.
Rudder installed and lower wing glued in place.
Canopy hatch finished.
Upper wing ready to be glued in place. ( note wing assembly guides included in plans)
Upper wing attached, Landing gear installed.
Rear view.
Close up of cockpit area. This style of landing gear differs from the plans. Aluminum flat stock was used instead of a wire rod. Extra reinforcement needs to be added inside the fuselage floor for this type of landing gear.
Decals installed. Rear view.
Servos location. Battery sits inside back of power pod mount.
Finnished bottom af the 40" PT-17
Top view. Ready for maiden flight.
40" PT-17 Stearman second flight
Building the two PT-17 Stearmans has been a lot of fun. The 40" Stearman flyes more scale then the MM size does, however the MM PT-17 can still slow down for some gorgeous fly-by's. The MM is a little easyer to assemble, and the 40" PT-17 is easier to fly. The ailerons on just the lower wing are very effective. Both are well worth the time to build and fun to fly.
0 comments