GWS-51D Mustang

GWS P-51D Mustang

I bought my GWS P51-D mustang 9 month ago from Hobby Loftet in Stjørdal. I build it after the plans with landing gear and functional rudderservo. I got the version with 300C power plant with a 10x8 gws prop. My first battery was a 7 cell 700mAh, NiMH battery.

Building
Building the plane was a no brainer as I can recall. I little bit difficult to get the aileron rods to be firmly attached to the aileron, so I used some duct tape and pretty much 5 minute epoxy. In matter of fact i did not use the GWS glue at all, only 5 minutes epoxy all the way. It think it has better properties sticking onto foam, it is stronger and you do not have to wait for the long drying process of the GWS glue.

First Flight
Enough with the building, the reason I´m writing this article is because there was several issues with the flying. It was a cold winter day in Trondheim, Norway and I was going to maiden this small bird for the first time. First time it actually took of, i flew 2 rounds on full throttle, first time i reduced the power the plane stalled (tipped) in the first turn. The bank angle was about 30 degrees I would say. It was unrecoverable. I dived as long as I dared, stopped the spin, and tried to yank it the air again using a little up elevator, but it stalled again.

Later that day i made several attempt, and i got it in the air only once. The rest of the time it either would not take off or it would tip stall just after getting in the air due to pre-mature take offs. The airstrip was long, but it is hard to make that plane track straight enough for a 100 meter take off roll. I made my conclusion that this plane would not be flying using stock setup, at least it would not be pretty.

First modification
I decided to add another cell to the battery pack to increase the power. Actually I was a bit discourage with my first experience and did not try this until spring. During the winter i also took of the rudder servo and linkage and glue the rudder in place as well as removing the landing gear totally. This time it actually flew, not great but I could hold it in the air as long as I wanted. However, I knew it would not be one of my favorite aircrafts. In the mean time I bought a Alfa Model FW190A-8 which is a complete different story, flies excellent with stock speed 300 motor and 5:1 gear and a 9x6 APC prop.

The Solution
During Notodden airshows 2004 I saw this brushless motor at smallsize´s booth. A Eflite 400 Park, I think it is called. I bought it, reasonably priced with retail at 599 NOK. Together with this motor I got a 3-Cell 1900mAh ThunderPower LiPo pack. The neat feature with this Eflite motor is that it comes with an adapter disk in aluminum with makes it fit directly into the stock GWS gear. The swap between the standard 300 motor and this one in the mustang was done in less than 5 minutes. Then I carved out some more foam to make space for the big battery. After installation the complete bird weight waas 460g against 430g before using the 9.6V NiMH @ 700mAh. GWS specifies the flight weight to be max 400g, however it will not be using the kit unless you go with a really small battery pack. I found the weight of 460g to very encouraging, remember I know have nominal power source of 11.1V @ 1900mAh.

Tried it today (12.sept.2004), wow! Now it flies, like a rocket. No bad tendencies at all. The plane actually works, its fast and responsive.