HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 20, 2011, 10:15 PM
Registered User
Cheese5's Avatar
United States, CA
Joined Jul 2010
4,380 Posts
Quote:
Originally Posted by ViperZ View Post
Hey all, I just joined the PZ Micro P-51 club as a father's day gift to myself....

I have a slight issue with it out of the box. I launched the plane and it immediately nose dived into the ground. It wasn't until I trimmed in max amount of up elevator that I was able to fly the plane, however it just does not feel right. Even thought there is an noticeable amount of up elevator trimmed in at neutral stick, I still have to fly with a slight up elevator on the plane to prevent nose diving.

I checked the CG of the plane, and it is actually slightly tail heavy at the 35mm CG point from the leading edge at the fuselage. Note I immediately removed the main landing gear before I took it out, so I'm not sure why out of the box it would require so much up elevator bias. I may try adding some weight to shift the cg even further back.

Can somebody help with other ideas?

Is the measured 35mm CG point form leading edge of the wing at fuse absolute? At the chord of the wing (where it meets the fuse) it is actually wider there than the rest of the wing. I assume at that point where the wing meets the fuse is the point of reference to measure out the 35mm.

Other than that the plane is fun to fly... I noticed the plane would not loop, when full up elevator was applied. Rather it would just climbout, and then hammer head over, or flop over. This leads me to believe the CG has to be off..
My CG is at 37mm, I like having a bit more elevator control over stability. I think your motor thrust angle is off. That would explain nosing into the ground. Try this: Fly high (if you can, if not then just hand launch the mustang) and see what it does. Next throw it (or fly it) and put the mustang in a dive. If the mustang pitches inwards then it is tail heavy. If it heads out of the dive then the mustang is nose heavy. THe ideal thing it will do is "glide".(these tests should be done with the elevator mechanically trimmed at 0 degrees. Repeat these tests with motor on and off and see if there is any difference. Best of luck!
Cheese5 is online now Find More Posts by Cheese5
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 20, 2011, 10:18 PM
Registered User
Cheese5's Avatar
United States, CA
Joined Jul 2010
4,380 Posts
I finished fixing the mustang. Now it weighs around half a gram less than before(I took out the battery plug to the RX since the BL plug connected right to the motor ports so the other wire wasn't needed. Hopefully it will fly the same or better.
Cheese5 is online now Find More Posts by Cheese5
Reply With Quote
Old Jun 20, 2011, 10:18 PM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
Quote:
Originally Posted by cincinnatus View Post
I've had mine only about a month and am certainly no expert. I have never checked the CG either, although it seems hard for me to believe it would be off THAT much. It is so light with so few parts and distinct places for them to be.... Is the tail assembly seated properly?

I think, maybe, that you should not be trying to trim the elevator so much with the xmitter. Rather, you should probably expand/contract the U-shaped part of the rod to get the elevator where you want it with 0 trim, and then trim from there. There is only a certain amount of throw in the servo by default, and if you are already trimmed to the max then when you apply more elevator there just isn't that much more to give.

That's my noob input, FWIW. Mine flew flat at neutral with 0 trim for a long time, but I do seem to have to adjust it from time to time now for some inexplicable reason. BTW, it will do very nice loops, too.

The tail assembly does look seated properly... I agree, I should not have to trim it so much, however it was just in compensation while the plane was flying. I don;t think adjusting the control rod is the fix either, because either way, whether it's done in the Tx or linkage, there is to much surface deflection (up) on the elevator for this to be normal...
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 20, 2011, 10:20 PM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
Quote:
Originally Posted by Cheese5 View Post
My CG is at 37mm, I like having a bit more elevator control over stability. I think your motor thrust angle is off. That would explain nosing into the ground. Try this: Fly high (if you can, if not then just hand launch the mustang) and see what it does. Next throw it (or fly it) and put the mustang in a dive. If the mustang pitches inwards then it is tail heavy. If it heads out of the dive then the mustang is nose heavy. THe ideal thing it will do is "glide".(these tests should be done with the elevator mechanically trimmed at 0 degrees. Repeat these tests with motor on and off and see if there is any difference. Best of luck!
Thanks, I may have to give it a go...
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 20, 2011, 10:43 PM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
I just did a un powered test glide (hand launch) and the plane nose dived to the ground. I took the battery out and it still dived. I checked the control surfaces and they were all pretty neutral.

I then taped a quarter to the back part of the fuse, it was too tail heavy and stalled out. I then taped a penny in the same place. It glided much better now. CG point is about 38.33mm

OK, I'm going to the park to test it with the penny attached.
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 20, 2011, 11:19 PM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
I think it's thrust line. As soon as I powered it up and hand launched it, it nose dived into the ground. Again it wasn't until I trimmed in up elevator, that it it would launch, even then I still had to apply a constant ump elev stick, to keep it in the air. It certainly feels as it's fighting a fine line between dive and stall. It would not loop, and would only climb out. I have the bigger BL PZ P-51, it flies very neutral, unlike this one out of the box...

So Do I just cut into it and try to adjust the thrust line, or do I contact customer support and see what they recommend I do? It seems like one of those things that unless you know what the spec should be, it's going to be hit and miss...

Attached are pictures of how much up elevator I applied just to get it to fly. I still had to apply a constant up elevator on top to keep it form nosediving...
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 20, 2011, 11:49 PM
Registered User
Cheese5's Avatar
United States, CA
Joined Jul 2010
4,380 Posts
Quote:
Originally Posted by ViperZ View Post
I think it's thrust line. As soon as I powered it up and hand launched it, it nose dived into the ground. Again it wasn't until I trimmed in up elevator, that it it would launch, even then I still had to apply a constant ump elev stick, to keep it in the air. It certainly feels as it's fighting a fine line between dive and stall. It would not loop, and would only climb out. I have the bigger BL PZ P-51, it flies very neutral, unlike this one out of the box...

So Do I just cut into it and try to adjust the thrust line, or do I contact customer support and see what they recommend I do? It seems like one of those things that unless you know what the spec should be, it's going to be hit and miss...

Attached are pictures of how much up elevator I applied just to get it to fly. I still had to apply a constant up elevator on top to keep it form nosediving...
For the thrust line see if you can push the motor down a bit (careful not to bend the shaft). Cut it open (only way you can access the insides) and add some glue to support it. Other way would be removing the gearbox, and glue the gearbox back while applying constant pressure so that the motor points slightly up (or neutral if you like). I like to have some up thrust with my mustang because it doesn't fly that well inverted. So most of my flying is done upright (inverted is saved for my sukhoi xp)

I don't think it will be a hit or miss. Just put the motor at neutral or slightly up so that the mustang will stay put or climb while throttle is advanced ( they can be balanced out with some down elevator, unless you are going to fly inverted, up thrust will help the micro mustang climb faster). Does the bigger mustang fly like the micro one (power wise?)?
Cheese5 is online now Find More Posts by Cheese5
Reply With Quote
Old Jun 21, 2011, 12:01 AM
Power Wheels Guru
UNGN's Avatar
Southlake, TX
Joined Jan 2008
7,327 Posts
Quote:
Originally Posted by ViperZ View Post
I think it's thrust line. As soon as I powered it up and hand launched it, it nose dived into the ground. Again it wasn't until I trimmed in up elevator, that it it would launch, even then I still had to apply a constant ump elev stick, to keep it in the air. It certainly feels as it's fighting a fine line between dive and stall. It would not loop, and would only climb out. I have the bigger BL PZ P-51, it flies very neutral, unlike this one out of the box...

So Do I just cut into it and try to adjust the thrust line, or do I contact customer support and see what they recommend I do? It seems like one of those things that unless you know what the spec should be, it's going to be hit and miss...

Attached are pictures of how much up elevator I applied just to get it to fly. I still had to apply a constant up elevator on top to keep it form nosediving...

Check the CG per the manual. All of my mustangs were tail heavy.

Did you bend the U-bend to get your TX trims back to neutral with up trim?

I never noticed the mustang to be pitch sensitive and once its trimmed, it flies on rails.

To get it to climb/loop, move the control rod to a hole closer to the elevator. If it wants to stall, put some washout in the wings by slightly twisting the tips of the ailerons up and the roots down.
UNGN is offline Find More Posts by UNGN
Reply With Quote
Old Jun 21, 2011, 12:22 AM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
Quote:
Originally Posted by Cheese5 View Post
For the thrust line see if you can push the motor down a bit (careful not to bend the shaft). Cut it open (only way you can access the insides) and add some glue to support it. Other way would be removing the gearbox, and glue the gearbox back while applying constant pressure so that the motor points slightly up (or neutral if you like). I like to have some up thrust with my mustang because it doesn't fly that well inverted. So most of my flying is done upright (inverted is saved for my sukhoi xp)

I don't think it will be a hit or miss. Just put the motor at neutral or slightly up so that the mustang will stay put or climb while throttle is advanced ( they can be balanced out with some down elevator, unless you are going to fly inverted, up thrust will help the micro mustang climb faster). Does the bigger mustang fly like the micro one (power wise?)?
I don't mind popping the hood and sorting it out, however I'm just disappointed it would be soo of out of the box.

When I have the Micro P-51 is flying level in fast forward flight, it does feel like the bigger P-51, and I'm sure once the thrust line is sorted out, it will behave much like it. I picked up the micro for flying at the park at the end of my street. The Bigger P-51 I need to get in my car and head down 10 blocks. However I certainly love the feel of the big P-51! I just finished flying it tonight and it was gorgious! I even took my Champ out, but I left the micro P-51 at home until I tried those things tonight.

I'm going to call the hobby store where I picked it up and see what they say. If I'm left to my own devises I'll adjust it, however I just wishe dthey woudl say bring it back for a replacement...
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 21, 2011, 12:28 AM
This is my Nemesis....
ViperZ's Avatar
Canada, SK, Saskatoon
Joined Jan 2011
2,008 Posts
Quote:
Originally Posted by UNGN View Post
Check the CG per the manual. All of my mustangs were tail heavy.
Did, it was 35mm as spec...

Quote:
Did you bend the U-bend to get your TX trims back to neutral with up trim?
Why? You would think the plane would fly with all control surfaces at neutral, or close to.... The amount I showed in the the picture is rediculious I think. Thats not right.....


Quote:
I never noticed the mustang to be pitch sensitive and once its trimmed, it flies on rails.
Thats what I sort of expected, but it's not the case... Mine nose dives with power, this is withthe CG shifted back to tail ~ 39mm

Quote:
To get it to climb/loop, move the control rod to a hole closer to the elevator. If it wants to stall, put some washout in the wings by slightly twisting the tips of the ailerons up and the roots down.

Again, I'm sure its' something thrust line, or wing camber related.. It's just not right....

Thanks!
ViperZ is offline Find More Posts by ViperZ
Reply With Quote
Old Jun 21, 2011, 10:55 AM
Registered User
AvistarAddict's Avatar
Joined Sep 2009
245 Posts
Make sure the horizontal stabilizer is seated properly. It should be flush to the fuselage. I had this problem once on a rebuild of mine, the front of the horizontal stab was raised 0.5mm and it dived until I fixed the the angle of incidence.
AvistarAddict is offline Find More Posts by AvistarAddict
Reply With Quote
Old Jun 21, 2011, 12:06 PM
Registered User
Cheese5's Avatar
United States, CA
Joined Jul 2010
4,380 Posts
Quote:
Originally Posted by ViperZ View Post
I don't mind popping the hood and sorting it out, however I'm just disappointed it would be soo of out of the box.

When I have the Micro P-51 is flying level in fast forward flight, it does feel like the bigger P-51, and I'm sure once the thrust line is sorted out, it will behave much like it. I picked up the micro for flying at the park at the end of my street. The Bigger P-51 I need to get in my car and head down 10 blocks. However I certainly love the feel of the big P-51! I just finished flying it tonight and it was gorgious! I even took my Champ out, but I left the micro P-51 at home until I tried those things tonight.

I'm going to call the hobby store where I picked it up and see what they say. If I'm left to my own devises I'll adjust it, however I just wishe dthey woudl say bring it back for a replacement...
My mustang also came defective out of the box. The white motor gear was warped so flight time was zapped from the battery. These micros just need some fine tuning. So far the only micro that I haven't needed to fix out of the box was the MSR. All the foamies needed some adjusting to get it right. But once the micro is fine tuned then it flies pretty well .
Cheese5 is online now Find More Posts by Cheese5
Reply With Quote
Old Jun 21, 2011, 12:21 PM
Registered User
AnbuPunk's Avatar
United States, MI, Davison
Joined May 2010
546 Posts
when i first got mine it had a cracked vertical stabilizer. i took it back to the hobby shop and we went through 3 more on the shelf before we found one that wasn't cracked.
AnbuPunk is offline Find More Posts by AnbuPunk
Reply With Quote
Old Jun 21, 2011, 12:31 PM
Registered User
DoomsDay's Avatar
Charlotte Douglas, NC
Joined Sep 2003
3,017 Posts
Quote:
Originally Posted by Cheese5 View Post
My mustang also came defective out of the box. The white motor gear was warped so flight time was zapped from the battery. These micros just need some fine tuning. So far the only micro that I haven't needed to fix out of the box was the MSR. All the foamies needed some adjusting to get it right. But once the micro is fine tuned then it flies pretty well .
Pretty much my exact same experiences with the micros as well! my p51 issue was the landing gear itself, but almost all my micros have had some issue out of the box that was easily corrected but for a new pilot, it could be very frustrating.
DoomsDay is offline Find More Posts by DoomsDay
Reply With Quote
Old Jun 21, 2011, 03:27 PM
Fly, be free! (splat)
United States, CA, Danville
Joined Jan 2008
1,393 Posts
Quote:
Originally Posted by DoomsDay View Post
LOL Cheese. I outside looped my UM P51 all the time. However, mine was stock and not brushless.
Mine is brushless and I can outside loop - I do go gently into the loop. I don't have all of the tape down the side of the fuselage (probably your problem Cheese), but I do have a bit in the front and middle as well as the back.
jdwolters is offline Find More Posts by jdwolters
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion 15" Parkzone Micro Cessna 210 flyingace451 Micro Ready-to-Fly 16 Aug 09, 2007 05:11 PM
Discussion parkzone Micro Cessna 210 RTF mecevans Micro Ready-to-Fly 7 Apr 30, 2007 02:14 AM
Alert Parkzone Micro Cessna Hugequark Scratchbuilt Indoor and Micro Models 28 Apr 18, 2007 02:38 PM
New Product parkzone micro cessna gunracer Parkflyers 18 Apr 16, 2007 06:01 PM