100mph 800mm FT Mustang - FREE PLANS

by nerdnic | September 3, 2014 | (8) Posted in Projects

 

DETAILS

I have been flying 800mm planes for a few months now and I love my 800mm Spitfire, so I figured why not make an 800mm FT Mustang?

 

PLANS

I have added the plans here.

 

ELECTRONICS

Motor - NTM 35-36 1800kv 910w
Battery - 2000mah 45c 4S 
ESC - Dynam 70a
Prop - 7x6 APC 


PICS

 

REVEIW

Pros
For an 800mm plane it performs well. It is quick, light in the air and doesn't stall very easily. It looks great and I would give it a B for high wind performance. I flew it today in 15 MPH wind and it got tossed around pretty good but overall held its own. Inverted was great, it liked being upside down.

Cons
Slow speed - Not great. I had a few close calls with slow speed stalls. Made landing a bit tricky.
Glides - I dropped speed really fast and had to give a lot of corrections to keep it straight.
Elevator - This bird suffers from the squirrely issue that some warbirds run into where giving it 'too much' elevator will cause a weird tippy, stall type behavior. I had to dial back my elevator quite a bit to get rid of the issue, to the point where I didn't feel like I had enough control over the plane at all times. I could still fly fine but I lost a lot of acrobatic capability.

All in all 
I like it. The cons are workable and it's fun to fly. I like how it looks in the air and I got a lot of compliments from other pilots. The 800mm FT Spitfire performs better in pretty much every way so that will continue to be my main go to plane for now, but I won't be putting the 800mm FT Mustang away anytime soon.

COMMENTS

alibopo on September 12, 2014
I'm very interested in the 'squirrelly' behaviour with the elevator - I've been experiencing that with a recent build. At first I didn't 'get' that it was an elevator issue. Once it became clear that was the 'cause' of the behaviour I dialled down my elevator throws and that seems to have overcome it, but like you I wonder if I've enough control left. Have you researched the cause, or can you point me to any research/threads on the issue. Interestingly, my plane has an 840mm wingspan. I wonder if it's some sort of 'sad' (as opposed to sweet) spot issue to do with the scaling?
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nerdnic on September 12, 2014
Hey there. I think the scale has something to do with it. The elevator surface is just very small. I have 0 issues with my 800mm Spitfire but the elevator surface is very large.

One thing I noticed with the Mustang is that the size of the surface that does not have the control horn was actually being forced down and bending, creating a elevon effect. This was making the issue worse. I stiffened up this by adding popsicle sticks to the bottom and top and the issue isn't as bad but it's still there.
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alibopo on September 12, 2014
Hi, thanks for replying. I tried reducing my angle of incidence, in case the wing was causing a 'ballooning' effect, and that seemed to help. These planes do fly quite fast, so a momentary 'excess' of lift could be an issue. I also replaced the elevator servo and the receiver, in case it was a signal/interference issue due to a fault with either of those. If it's the same issue, I found it a bit 'scary' - making the plane unpredictable. I also wondered if it had something to do with the width of the horizontal stab. compared to the width of fuselage where it connected, maybe the tail is twisting under load? If anyone else out there can throw light on the problem I'd be interested to hear their thoughts. Oh, and I should have said this before, nice builds - you've been busy! :)
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nerdnic on September 12, 2014
Thanks! I think you might be onto something, there's gotta be some equation that explains what's happening. I'm not smart enough to actually figure it out though, my experience is 'well, try it and see what happens' :-P
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anonymous rc pilot on September 12, 2014
thats quite a watt to foam ratio!
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nerdnic on September 12, 2014
I know! I love it! haha.
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earthsciteach on September 12, 2014
Pffffttt. You can fly lower than that.
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nerdnic on September 12, 2014
Haha, I clip the weeds all the time :-) I've actually lost 2 planes in this field from flying too low, the wings just rip right off and get stuck in the weeds and the fuse goes another 20 feet or so before stopping. It's pretty spectacular.
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Flite test for life! on February 23, 2015
thats pretty cool!

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100mph 800mm FT Mustang - FREE PLANS