Multiplex Stuntman - RC Groups
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Dec 15, 2001, 08:02 PM
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Bill Glover's Avatar

Multiplex Stuntman

Have always thought the MPX Stuntman was a good looking little plane. Got to see one in the flesh today, seems to fly fine (though the one I saw didn't have the stock motor) ... but there's one really bad bit of design. To change the pack you have to remove the wing. That's bad enough, but in order to remove the wing you have to disconnect both aileron linkages as the servos are in the fus! This involves undoing a little screw on each aileron horn and pulling out the pushrod, so you lose the trim position every time. The guy also said he'd already dropped - and lost - one of the little screws on the field.

This has totally put me off the model, the cross-connected ailerons/elevators are a clever idea but seem to make removing the wing a real pain. And having no access hatch to allow pack changes is just stupid.

After all the neat design touches in their other electric models Multiplex seem to have fouled up with this one, which is a shame
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Dec 16, 2001, 11:02 AM
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I have just flown my Stuntman today (for the first time) and was really impressed with the performance. I was using 700Mah 7 cell nimh pack which gave me over 10 mins of flight time (stock 280 motor). It was a little low on power but i reckon with a 7/8 cell Nicad pack that should improve some.

As far as the problems regarding disconnecting the ailerons I found a solution by accident. My Tx would not mix so I couldn't use the coupled elevator/Aileron setup. Instead i stuck a servo in the wing for the Ailerons and separate servo for elevator (same as a usual plane). i also doubled the recommended throws to the surfaces. She flew great and was very snappy. Although more power would be good for vert performance.

Bill what motor setup did the stuntman you saw have?
Dec 16, 2001, 11:20 AM
310mph Kolibri T25 Swist
henke's Avatar

I also have a Stuntman! I configured it with 4xHS50, two mounted in the wing and two in the fuse(elev and rudder)....

canged to 5:1 SP300 9x5 on 8xSanyo700. works realy good and the wing is easy to dismount! batterychange is approx 20sek!

I think the plane is awsome! fies very good! no problem to hover!! or tourqroll(if you are a good pilot)

....but a totaly agree with Bill! the stoch setup is strange.... smoked the 280 on its first flight.....
Dec 16, 2001, 11:32 AM
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Sounds like a pretty good setup there. I think a speed 300 is the way to go, although with the 280 it is probably a little more relaxing.

What size ESC are you using (sorry for the dumb question but i'm a little new to this and still havn't figured out the Amp thing)

and whats your duration?

Dec 16, 2001, 04:38 PM
310mph Kolibri T25 Swist
henke's Avatar
Hi trickyrik

Iīm using a Schulze slim10, itīs an updated slim08 with better software for smoother running!

the "10" stands for 10Amp, a little more then the sp300 uses (approx 7A max)

if you donīt know the amp thing I can try to explain...

the Amps are the fuel! and you need a large enough carburator(ESC) to handle the fuel supply!

Sp300 uses approx 7A peak current, so you could probably use a 5A ESC, but as the 10A is the same size i choose it, to be on the safe side!

Using 8xNiCd270mah I get more power, but only for about 3min!

with 8xSanyo700(note!! not Twicell!!) I get unlimited percformance for about 7min! no problem to prop hang and then accelerating away!

Once I hang in the prop for 1minute or so!! I couldīt resist to begin tourqerolling but as Iīm no Chip Hyde it didīt work as I thought it shuld

some pix of mine and my friends Stuntmen! you probably donīt understand the Swedish text, put the pix are nice :-)

here are some pix of "tipshallen" a prefect indoor flying site!

almost forgot to say.... dont forget so glue a carbon stick under the horizontal stab!! mine broke and I crashed....
Last edited by henke; Dec 16, 2001 at 04:43 PM.
Dec 16, 2001, 05:02 PM
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Bill Glover's Avatar
The one I saw was using a Piccolo helicopter motor (not sure what size that is?). It was very quiet & smooth, he said the stock setup was pretty noisy. We were flying indoors, the Stuntman was too big and fast really but he did manage to roll it.

Here's a shot from last night that shows the 'coupled tailerons' in action.
Dec 16, 2001, 06:02 PM
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Cheers for the explanation Henket, I think I'm starting to understand.....

So each motor size has its own current draw (its not dependant on the battery size or type?). As i'm using the stock 280 with a 5amp speed control I should be ok with any batteries I choose to use.

Great flying site you have Henket and from the picture of your Stuntman it looks like you've removed some of the internal wood supports. Is that to allow more space for the battery packs or save weight?

On the subject of weight how much approx does your Stuntman weigh?

Good tip for the horizontal stabiliser cheers.

Its good to find another stuntman flyer as there was very little previous info available within the discussion forum regarding the plane. I think its excellent and cannot wait for the next calm day.

I think the piccolo uses a 280 motor.
Dec 16, 2001, 07:45 PM
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Neil Stainton's Avatar
> with 8xSanyo700(note!! not Twicell!!)

What cells are these? Are they NiMH? Are they the "industrial" 700's that Mamo are selling on

> 700erNIMH Sanyo-Industrie 700 mAh max 5 Amperé 44 x 10 mm / 12 g 5,50 DM 5,00 DM
> Twicell700 NIMH-Sanyo 700 mAh max 4 Amperé i.V. 44x10 mm / 12 g 5,00 DM 4,50 DM


Dec 17, 2001, 03:50 AM
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What are Twicell?
Dec 17, 2001, 03:59 AM
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Just did a search on Twicell and it appears they are the batteries as used by the Hornet Heli. Which is a coincidence as they are exactly the cells I am using.

Would I get better performance if I used a different type like Neil is suggesting
Dec 17, 2001, 08:14 AM
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Twicell is the Sanyo brand name for their NiMH cells, like Cadnica is their brand name for Nicad batteries.

Different models of Twicell have different charge/discharge characteristics and if you want to know more about it, here's the link.

Some of the cells are completely unsuitable for what we want to use them for, so make sure you understand what you are buying, particularly from an electronics/photo supply source. Like the cells used in emergency equipment (fire alarms etc) are designed for to be trickle charged all the time, etc. etc.
Dec 17, 2001, 08:28 AM
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Bill Glover's Avatar
Originally posted by trickyrik
So each motor size has its own current draw (its not dependant on the battery size or type?). As i'm using the stock 280 with a 5amp speed control I should be ok with any batteries I choose to use.
No, that's not true.

The current a motor draws will depend on the prop you're using, plus the number and TYPE of cells. If you draw too much current you will burn out the motor or speed controller ... both of which have limits. You can also damage some types of cell by pulling more current from them than they are intended for (at the very least they will get hot and deliver nowhere near their rated capacity).

Different types of cell have different 'internal resistance'. Some, like the Sanyo AAA nimhs ("Twicells") have high resistance and will deliver less current than other types.

A practical example, my 280BB (not the same as a 280!) running direct drive with a 4.7x2.3 folder pulls 7.4A with seven Sanyo AAA nimhs. But with seven Sanyo 500AR nicds it pulls over 13A! That's because the nimhs restrict the current flow (they are intended to give 3-5A maximum) and the nicds don't (they can deliver up to about 20A). So when I switched from one to the other I was exceeding the rating of my speed controller (11A), so I went down to 6 nicd cells ... dropping the current to around 9A (still more than the seven-cell nimh packs gave!).

But the amp draw on both types of cell would go up if I fitted a bigger prop, or down with a smaller one.

Have you read the Ezone FAQ (link at top right of screen)? There's a lot of good stuff in there ...
Dec 17, 2001, 01:56 PM
310mph Kolibri T25 Swist
henke's Avatar
Hi all!

Sanyo makes Twicell 720mAh (they are only 700mAh but it says 720mAh anyway)

if I got the right informatoin Sanyo bought Thoshiba reasently... and the Cell I called "Sanyo 700" (Niel found them called "700erNIMH Sanyo-Industrie 700 mAh max 5 Amperé 44 x 10 mm") is renamed to "Thoshiba 700"

but the important thing is: Twicell delivers less power then the Sanyo700/thoshiba700!!


the Amp changes depending on cell count and propzize as Bill said!

this is not exact numbers, only one way to explain:

Speed 300 using BIG prop =10A approx 400g thrust
Speed 300 using small prop=4A approx 200g thrust...
Speed 280(as in your S-)man usaing BIG prop=4A 250G thrust

Power=Watt Watt= Amp X volt

100watt = 10cells (10volt) and 10Amp = approx 400g thrust

100watt = 14cells (14volt) and 7Amp = approx 400g thrust

less Amp= more flight time! more cells= heavier=less flight time

the Amps are the "thing" producing heat, thats why BIG planes use up to 58cell or more, then they get 58volt x 40Amp=2300watts, without getting to much heat!

so, if you fly a Speed 300 with 5A ESC and the ESC donīt get hot then its OK! if ESC get hot itīs not ok

one again, this was just a simple way to explain....not exact calculatons!!

trickyrik are you getting it??
Dec 17, 2001, 01:59 PM
Registered User
Cheers Bill thats explained it well. I thought I was being a little too hopeful that it was a staight forward thing to work out. It appears there is a lot to learn.
I have checked out the FAQs and found it very useful but the Current thing wasn't covered in much detail.

I recently bought a multimeter so I will test whats going on in my setup.

Eventually I should get the hang of it all.
Dec 17, 2001, 02:10 PM
Registered User
Henket and Bill

Thanks for your time to explain this to me. At last I think i've got it!!!, I feel kinda stupid but if you don't ask I guess you never find out.

I'm going to upgrade my stuntman with a s300 and get a higher rated speed control.

I guess with the extra weight the Stuntman should handle wind better.

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