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Jul 05, 2004, 10:10 AM
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Patrick Plawner's Avatar
Thread OP

Multiplex Magister - PART 2


This thread is the continuation from the initial thread located at:
https://www.rcgroups.com/forums/show...3&page=1&pp=15


Anyway, just came back from 5 test flights today and here is the feedback:

- Jeti 30/3 with 12x6 and 8 cells 3300 provides about 6:00 of safe flight, with motor management
- Loops are piece of cake, from level flight
- Rolls are easy to do, but make sure you have enough speed and don't wait at all, while on the edge as the plane is heavy and will drop there
- Flaps help A LOT, for landing on short runways, I tried with and without and without is much more difficult as the plane either glides, either stalls. Since the stall speed seems pretty high, the plane, when touching the ground is still fast and it's weight takes it for some time on the runway.
- When the flaps get extended, there is no need to modify the elevator at all.
- The plane NEEDS very much rudder management, in order to achieve clean and coordinated turns. This is certainly due to its size and weigth, but it is required. Not doing it makes the plane slide, like any real plane would.
- The rudder is not just here to be nice, on this plane, it works effectively. Forward slip on landings are therefore easy to do, and it might be a good way to slow the plane down, if too fast on final approach
- Beware of the elevator. It is very sensitive. Never forget than if you pull to fast on the elevator, you might stall, regardless of the plane's speed ! I actually tried to force a stall at high speed and sudden sharp elevator up but did not succeed. Possible that I was too slow anyway.

Patrick.
Last edited by Patrick Plawner; Jul 05, 2004 at 10:50 AM.
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Jul 05, 2004, 12:10 PM
Plane Crazy
Patrick: thanks for starting the new thread

define your use of flaps? do you lower the ailerons as flaperons, or did you build flaps?

I agree with your assesment on all points (except the roll bc I haven't rolled it yet)

Mart:
I am glad to hear your fund manager has aquired the new position and title of "supporter of the rc hobby"

What kind of battery ar you planing to use?
I don' t know the mots you mention but the himax sounds good, I think 40A with 12x8 even with 8 cells would be well enough power
Jul 05, 2004, 12:34 PM
Registered User
Patrick Plawner's Avatar
Thread OP
Flaps done by flaperons.

I do put them quite down to get as much drag as possible, but still, the plane glides well. It does have an impact on the descent rate though.
Jul 05, 2004, 02:42 PM
Registered User
Bill Glover's Avatar
Patrick, I am very surprised that rudder is needed for 'clean' turns ... this is almost unheard of in a trainer. Perhaps it needs some aileron differential (or more differential).
Latest blog entry: Eachine QX65 FPV quad review
Jul 05, 2004, 03:47 PM
Registered User
hmm..well the AXI is a bit out of my price range right now, but I did some more digging and found this MPJet 26/45-20D with the front mount I need for $68.90 at HL. Maybe that will work with the Jeti 30-3p ESC and 12x6 prop? I just got my tax refund sooo..it will just cover that combo. here it is at the bottom of the page. I dont think that one has been mentioned before. whaddaya think?
http://www.hobby-lobby.com/brushless_mpjet.htm

If the GP GD600 2.5:1 gearbox and Electrify T600R won't work, then I'll go with the brushless if you guys think its a good match. Patrick, VERY cool pics and video's, they are much appreciated, It got me even more excited to see it in the air in action. I think I will need professional financial counseling when this ones all over..

Keith S.
Jul 05, 2004, 04:13 PM
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Patrick Plawner's Avatar
Thread OP
Hi Bill,


I put the standard 20% differential and still, I saw it slide if not using the rudder. It does not need a lot of it, and you can turn without it, but it is better with.

Actually, I think any plane, after a certain size/weight, needs rudder compensation, as the centrifuges forces play a big role then, when you try to turn.

Patrick
Jul 05, 2004, 04:27 PM
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Patrick Plawner's Avatar
Thread OP
Keith,


glad you liked the video and pictures.
No one was with me today so I could not take all the test done on video (Sunday is a working day here) but I will try soon.

Also, now that I am more or less done with the basic tests, I'll go and try the towing system.

First I'll carry just a dummy and if I see than the plane is strong enough to carry, then we will try with a real glider. the small LO100 will be the first one to be tried
Jul 05, 2004, 05:13 PM
Plane Crazy
Bill
I don't know from expereince how a"real" trainer is supposed to behave
I have quite some differential now on the M and it still behaves like a full size plane, i.e. a Cessna 152 or such. If I start the turn with just the ailerons, the tail will "droop" so I need some rudder to beginn the turn, in the turn its rather neutral (as far as I can tell) depending on bank angle, but if I have a fixed aileron-rudder mix, it will eventually turn the nose down.

I am talking turns with 40+ degrees bank bc I haven't mastered to do more subtle changes of direction yet
Last edited by splash99; Jul 06, 2004 at 02:11 AM.
Jul 05, 2004, 05:27 PM
Plane Crazy
Keith
Not enough information on that site.
If it's intended to replace 600 motors, it might just be enough

there's more videos here

they were added earlier in the first part of the thread.
The first one is of the maiden takeoff when the motor quit after 2 seconds.
A take off and a landing by an experienced pilot, and a stall/recovery/crash by an inexperienced pilot

BTW it' s not a website like Patricks, more of a place to store videos.
The two Easystar videos I had to take out bc of space restrictions
Jul 05, 2004, 05:38 PM
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Patrick Plawner's Avatar
Thread OP
Splash99,


nice videos. I like how you saved the Magister on the crash. Well done as it did not start well.
Jul 05, 2004, 06:10 PM
SlopeHead
jcosta's Avatar
Quote:
Originally Posted by splash99
Keith
Not enough information on that site.
If it's intended to replace 600 motors, it might just be enough

there's more videos here

they were added earlier in the first part of the thread.
The first one is of the maiden takeoff when the motor quit after 2 seconds.
A take off and a landing by an experienced pilot, and a stall/recovery/crash by an inexperienced pilot

BTW it' s not a website like Patricks, more of a place to store videos.
The two Easystar videos I had to take out bc of space restrictions
Splash,

If you need space for videos let me know, I may be able to arrange something.
OTOH, Patrick can probably also find you some space...
I definitely have to get a "video operator" - either convince my wife or my father in law to make a few sailplane videos...
Jul 05, 2004, 06:15 PM
Registered User
Bill Glover's Avatar
Quote:
Originally Posted by Patrick Plawner
Actually, I think any plane, after a certain size/weight, needs rudder compensation, as the centrifuges forces play a big role then, when you try to turn.
I've had high wing / aileron models up to 90" span and 14 lb AUW, and probably flown 100+ aileron trainers (I was a club instructor for many years). None of them ever needed coordinated rudder to turn nicely.

Honestly, this behaviour is not 'normal'! Have you measured the actual up/down movement of the ailerons to confirm that you really do have some differential?
Latest blog entry: Eachine QX65 FPV quad review
Jul 05, 2004, 06:15 PM
SlopeHead
jcosta's Avatar
Quote:
Originally Posted by splash99
Bill
I don't know from expereince how a"real" trainer is supposed to behave
I have quite soem dihedral now on the M and it still behaves like a full size plane, i.e. a Cessna 152 or such. If I start the turn with just the ailerons, the tail will "droop" so I need some rudder to beginn the turn, in the turn its rather neutral (as far as I can tell) depending on bank angle, but if I have a fixed aileron-rudder mix, it will eventually turn the nose down.

I am talking turns with 40+ degrees bank bc I haven't mastered to do more subtle changes of direction yet
How much aileron-rudder mix do you have? And how much differential? You should have at least 100-70 differential (for 100 mm going up, 70mm going down on other side), if not 100-60.
Last edited by jcosta; Jul 05, 2004 at 06:18 PM.
Jul 05, 2004, 06:18 PM
Registered User
Bill Glover's Avatar
Quote:
Originally Posted by splash99
If I start the turn with just the ailerons, the tail will "droop" so I need some rudder to beginn the turn
That definitely sounds like adverse yaw. Does it turn better at higher speed?
Latest blog entry: Eachine QX65 FPV quad review
Jul 05, 2004, 10:53 PM
sensitive artsy type
Treetop's Avatar
Keith, I once asked Hitec about getting MPX parts that were not available here (such as the 680 permax motor and gearbox in your case) and they told me Tower could special order them. For what it's worth. tt

I can't understand the MPX German site not having information about the Magister, anyone else find this strange? tt


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