As I browsed along the trade stands at Middle Wallop a few year’s ago, my gaze fell upon the little P51D Mustang Street Fighter, from Free Air. The nice man at MCB recommended a suitable 150Watt bell type motor and Hyperion Titan 10 ESC, as the perfect accompaniment.
The Street Fighter’s are a range of simple 3 channel (Elevator, Aileron & ESC) expanded polypropylene EPP profile fun models, based loosely around a selection of WW2 warbirds. They are suitable as ether park flyers or Combat fighters. So cash changed hands and home I came, pleased as punch with my new little toy.
Forget the box lets get at the model!
The model it self comes in 4 main pieces. A profile fuselage, the fin and rudder, horizontal stabiliser, and a complete main wing assembly. All the EPP foam parts are nicely cut and painted. The elevators and ailerons are ready-hinged. A bag of bit’s contains the control horns control rods and all the parts for the undercarriage. Theirs a simple set of black and white instructions, consisting of half a page of text and two sides of a computer drawn assembly storey board. A set of stick on decals completes the contents.
So like a good little model maker I sat my self down to read the instructions. The first item of which says please read the building instruction carefully before you begin!
It also states that due to it’s well engineered design it will only take about 60 minutes to assemble, That sound’s great to me.
The following line then goes on to say “It would survive unharmed many crashes and mid-air collisions in the air combat with other models.”
That also sounded good even if the English is a little suspect.
Well assemble about sums it up, apart from trimming up the control surfaces for free movement and fitting the control horns. So having glued the tail parts and wing to the fuselage with medium cyno, you effectively have a model ready for the fitting of the motor and radio.
I had decided early on not to fit the undercarriage to my model, I feel that a model of this size looks better in the air with out them, and as I intended to fly off grass all of the time there was very little point. There is a down side however with the vulnerability of the aileron servo, more on this later.
So I dispensed with the very nicely made set of little wire legs and wheels (They may fined there way in to an indoor model one day).
Following the picture story instructions, holes were cut in the EPP for the servos, radio, ESC and motor mount. The associated parts were then fitted and held with Cyno.
Then I came across the only minor problem with the instructions. They show the flight battery fitted through the bottom of the wings, however once the aileron servo is fitted I had insufficient room for anything else. So I cut a slot above the wing for my 750 or 1000mAh 3s flight packs, problem solved.
On the subject of changes to the plan. The aileron servo is fitted under the wing and is very vulnerable to landing damage, and more so with out the landing gear. To get round this on mine, I fitted a wire loop on the under side to keep the servo safe, and so far this has work fine. An alternative I’ve heard about is to fit the servo and links on top of the wing.
With the motor bolted into its mount and the ECS connected that’s it ready to fly. The only other thing left to do is add the stickers and paint to taste.
The Best Bit.
With a fully charged 3-cell li-po pack, hold the model by the canopy. Open the tap, and cast the model off in a gentle arc. Watch the model disappear straight up. Now add full aileron and do vertical rolls until the model is just a dot.
So there’s power a plenty, now shut the power off and wait, the model so light it takes an age to glide back down. With so little weight, and a wing that seems to be very efficient the model glide very well and can be flown incredibly slowly. But if you want the model down fast, then keep the power on and drive it down.
On the first few flights the roll rate seemed a little pedestrian, and this was down to the amount of flex in the foam ailerons. The addition of a carbon fibre stiffener set in to the ailerons soon had the Mustang zipping round.
The only limitation to this models acrobatics is its lack of rudder, but if you really wanted to you could find room to fit another servo and modify the tail, but I’m happy with mine just the way it is.
This model is just such great fun, burning holes in the sky. It’s at its best on a calm day, but it can cope with a reasonable amount of wind. I have one word of warning though if you do fly on a windy day. Don’t fly the battery pack out! (Not that a good Li-Po user would!)
You need the motor running to have any control authority, or you will end up with a long walk down wind to retrieve your model. How do I know? Don’t ask.
If you want a small park fly size model, with power to impress then this could be the model for you.
I have only one observation to add and that concerns the amount of flex in the model. This is due in the most part by the amount of power from the large motor set-up I have fitted. A 75 or 100W motor would be plenty big enough. Anyhow to counter this I have resulted to adding flat carbon strips along the Ailerons and down the length of the fuselage.