Anybody built Li l Mustang

[kc]

Anybody built Li’l Mustang a 49 inch Peter Miller design?

Li’l Mustang Peter Millers design published in RCModelWorld Dec 2004 seems to have everything.

( Note this is not the same as the RCME scale Midget Mustang design )

I searched my collection of free plans for something about 50 inch, sleek good looks, really aerobatic, scale like but not exact scale which needs scale colour scheme. Not complicated to build. Something which could be powered with a 400 watt brushless & modified easily to fit a top hatch to get access to the Lipo.

Peter described it as " just occasionally everything comes together and one finds that one has an extra special model. Li’l Mustang is one of those rare ones" Sounds promising!

But nobody else has ever mentioned it as far as I can see. Why didnt we see our flying fields full of these really smart models for the last 8 years?

Has anybody built Li’l Mustang and did it fly as well as Peter’s own model?

[Peter Miller]

I have noticed that it is rare for there to be much discussion on this forum about models from other plans services.

Li'l Mustang performs very like many of my other designs, in other words very well. Of course I would say that, wouldn't I

[Paul Irvine]

Hi Kc,

I built Li'l Mustang about 7 odd years ago. I wasn't a very experienced builder or pilot in those days but I pushed through and finished the job. I'm not sure if it was just me and my building skills, but the formers on the aft fuselage section didn't really match up on the measurements. Throw a ruler over the plans, in particular the vertical height of the formers then check them against the side profile of the model, you will pick up the errors in the drafting. It's a pretty little model and as Peter says everything just comes together on this one. I powered mine with a wankel engine, the performance was off the dial. It is an extremely light model, which I found made for some interesting landings, honestly this thing will just glide forever! I will hunt for some photos of mine and post them for you if I find them. Perhaps the only thing I would recommend upgrading is the landing gear. The bent wire unit I found to be too light; it would bend regularly and in doing so would damage the fuselage. From memory it is wired to a frame and the wires are then soldered. I would recommend putting a sturdy ply plate under the fuselage section and bolt a solid bent aluminum unit to the ply.

You’re going to love this model wait until you see how it can turn itself inside out! I broke mine on a cartwheel landing but I still have the plan and intend to build another next year, perhaps I’ll put the rotary in it again.

Enjoy

[kc]

Thanks Paul.

I had already seen that the formers are incccurate, in fact anyone can see at a glance even from the tiny plan in the magazine that F5 is inaccurate ( not symetrical! ) How these errors are not found before printing is beyond me. I know from previous comments that is not Peter's fault it's whoever redraws the plan ( always anonymous )

I have redrawn all the formers eliminating errors and with re-plotted holes for snakes due to moving the servos forward to help with CG. Also I have redrawn F1 for electric which means further forward and therefore smaller.

It is my intention to use a removeable piano wire U/C in the Boddington torsion bar style which is also used on Peter's more recent designs. Perhaps a fraction heavier but always works well and can be removed to be straightened in a vice

[Peter Miller]

I think it depends on the wire. Good old 8 SWG wire from SLEC etc is pretty good. The K&S 1/8" wire is a bit like wet spaghetti.

The usual problem with formers getting distorted. Not my fault, honest Gov. These days I make a very extra special effort to get them spot on.

I was very interested to hear about using Wankel power. I am just starting to build a model for that power. A little bigger than Li'l Mustang as it is designed so that I can change from an SC 32 to a Wankel on the field. Well, not too many people have Wankels. Both versions will be shown on the plan. In fact it will only be the cowl that is any different.

Yes, I have gone over to that system of under carriage. IT would well and is easy to straighten. I can also use shorter pieces of wire for each leg. IT would be very easy to modify Li'l Mustang to take that set up.

[John F]

I am looking to build this model in the newly painted and kitted out garage and need ideas on electric engine size, it is all very complex these days!

As far as I can work out, with 48" wing, 4lbs weight, it would need a 4250 - 800 if the original required a .32 engine. Is this about right?

Edited By Sarge on 25/09/2013 14:47:31

[kc]

None of the electric experts seemed to have replied yet......
...so I will offer my non expert opinion!
The 4250 -800 seems to be 720 watts while the Lil Mustang weighed only 4 pounds built for a glow. (Maybe an electric version could be a little lighter even ) So the often quoted 100 watts per pound minimum for aerobatics is well exceeded. Maybe that motor could be propped for less watts and so provide decent flying for a reasonable time. But what Lipo will you use?

[John F]

KC, your advice is always welcome. To be honest I have absolutely no idea what LiPo I'll be using!! That will be later on when I get around to the fuselage.

The elctrickery for aircraft has changed a lot since I last flew so the learning curve seems to be in a straight line at the moment.

[kc]

Well I wasnt offering advice but just my non expert comments in the hope it would bring further advice from experts!
I think you should consider how many amps are required for 720 watts ( for example) and how long the lipo would last at that current. My calculation ( may be wrong) is that 50 amps would be needed from a 4S and if that were a 4S3300 it would give only about 4 minutes full throttle flight. So you need to consider if that is enough and whether there is sufficient space and weight capability for a larger Lipo.
What I can give advice on is the construction. F1 may well need to be further forward for electric and therefore smaller to keep the shape. F2 may need the to be revised to make a hatch & could have a larger hole in it to take a large Lipo. But it may need a different u/c fixing - consider using the arrangement on later Peter Miller models like Swamp Rat, Harlequin, Oodallaly etc. This is side mounted ply to take a torque rod u/c. You might need a larger hole in F3 too in case a large Lipo needs to go well back for CG.

If you can build the model a bit lighter then the power requirement could be less or you could decide a moderate performance is sufficient. So I think you need to decide on the models target weight, motor & Lipo size at the earliest stage.

Edited By kc on 27/09/2013 15:40:04