CMPro P-51 (50 size) test flight crash  
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CMPro P-51 (50 size) test flight crash - 10/26/2007 5:27:33 PM   
Rob2007


 

Posts: 4
Joined: 4/16/2007
From: Spalding, UNITED KINGDOM
Status: offline 		I have recently finished CMPro's 50 size P-51 Mustang which I decided to test fly on Wednesday, the aircraft was powered by an OS 46 AX and finished, balanced etc as per the instructions.

The test flight was one the worst experiences I have had with an RC aircraft. Once the engine was properly set up and the aircraft range checked took it out onto the field for its maiden flight, and boy was I in for an extreme flight.

I opened the throttle for take off, gave it a bit of rudder to keep it on track and it left the ground and proceeded to enter a prop hanging position, I couldn't believe it, surely the C of G couldn't be so far out that the aircraft would want to go completely vertical. I couldn't seem to do much with it and it went over on to its back so I distinctively pushed down elevator for inverted flight, however I had full down elevator and it was sinking, this doesn't ring true if the aircraft was tail heavy. By this point the aircraft was coming towards me so I decided to shut the thottle and ditch.

The aircraft unfortunately did a cartwheel and has done quite alot of damage to the fibreglass fuselage.

Has anybody got any ideas as to what went wrong or has anybody had any similar experiences with CMPro's war birds.
       Post #: 1

RE: CMPro P-51 (50 size) test flight crash - 10/26/2007 5:46:24 PM   
Red B.


 

Posts: 935
Joined: 8/29/2002
From: Jonkoping, SWEDEN
Status: online 		The most probable cause is a tail-heavy condition. Did you check the C.G. before flight?
Because you entered invert flight from a prop-hanging attitude you airspeed was probably
very low. If the wing was stalled down elevator would not help in maintaining altitude.

Too bad...

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/Red B.

(in reply to Rob2007)
       Post #: 2

RE: CMPro P-51 (50 size) test flight crash - 10/26/2007 8:35:38 PM   
ForktailedDevil38



Posts: 45
Joined: 5/5/2003
From: Smithville, OH, USA
Status: offline 		Sounds to me like the CG was off and the plane was tail heavy. As was mentioned, you were probably flying too slow and were in a stall condition, making your control surfaces useless. Sorry about the rough first flight

(in reply to Rob2007)
       Post #: 3

RE: CMPro P-51 (50 size) test flight crash - 10/26/2007 9:49:38 PM   
bassfisher



Posts: 515
Joined: 10/28/2003
From: North Little Rock, AR, USA
Status: offline 		My experience with CMP Models (I have the .50 size Zero) is that the CG in the instructions is way off. You can look up the CMP Zero thread. I believe in the main spar balance point system. Yours is no the first CMP Mustang that has gone it because of the factory CG being wrong. I saw one at my field go in from about 10' after take-off. I have learned with my Zero to also add balsa longerons inside the fuse to add strength. The Fuse on my Zero was too soft. The longerons didn't add that much extra weight.

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It only takes two things to make an airplane fly -- AIRSPEED AND MONEY

(in reply to ForktailedDevil38)
       Post #: 4

RE: CMPro P-51 (50 size) test flight crash - 10/27/2007 12:13:19 AM   
Sturtz



Posts: 1496
Joined: 9/22/2004
From: El Reno, OK, USA
Status: offline 		Rob,,, they are not the best flying warbird CMP has to offer that's for sure. I cg'd mine slightly nose heavy the first few flights and found it to nose over on landings much worse than my other warbirds ever did. It has a bad stall tendency as well and if doing hammerheads you want to keep it nice and high. It's small and heavy. Not a good combo. I took it along to the field this summer and had a decent flight on it. "If you don't count the stalling." Flew a larger plane several flights and got back on the little P51 . It ground looped on me as well. Got it fixed and ready to go but I sure don't love this bird much. Saito .72 , 13x6 APC.

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Kurt
AMA# 794291
Saito Club #121

(in reply to bassfisher)
       Post #: 5

RE: CMPro P-51 (50 size) test flight crash - 10/27/2007 12:43:43 PM   
Hisham



Posts: 860
Joined: 2/13/2002
From: Beirut, LEBANON
Status: offline 		Rob2007,

do u still remember where was ur CG located on this plane???
am assembling mine am just waiting for the incowl muffler to arrive.

Hisham

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Scratch building is my Way of life.

(in reply to Sturtz)
       Post #: 6

RE: CMPro P-51 (50 size) test flight crash - 10/27/2007 1:20:48 PM   
Rob2007


 

Posts: 4
Joined: 4/16/2007
From: Spalding, UNITED KINGDOM
Status: offline 		This plane was actually my first venture into scale and I have clearly made a poor choice, can anybody suggest a good flying warbird for next attempt.

Hisham, I balanced mine as the instructions which was 85mm back from the leading edge and 1800mm out from the centre of the wing, clearly this was way off, I would suggest you contact the manufacturer/distributor to see if this value has been revised.

(in reply to Hisham)
       Post #: 7

RE: CMPro P-51 (50 size) test flight crash - 10/27/2007 3:15:49 PM   
maukaonyx


 

Posts: 118
Joined: 10/7/2006
From: salem, OR, USA
Status: online
quote:

ORIGINAL: Sturtz

Rob,,, they are not the best flying warbird CMP has to offer that's for sure. I cg'd mine slightly nose heavy the first few flights and found it to nose over on landings much worse than my other warbirds ever did. It has a bad stall tendency as well and if doing hammerheads you want to keep it nice and high. It's small and heavy. Not a good combo. I took it along to the field this summer and had a decent flight on it. "If you don't count the stalling." Flew a larger plane several flights and got back on the little P51 . It ground looped on me as well. Got it fixed and ready to go but I sure don't love this bird much. Saito .72 , 13x6 APC.



COOOOOOL pic. Looks very real till I enlarged the photo! Jon

(in reply to Sturtz)
       Post #: 8

RE: CMPro P-51 (50 size) test flight crash - 10/28/2007 4:31:14 AM   
Billville


 

Posts: 97
Joined: 12/26/2006
From: burbank, CA, USA
Status: offline
quote:

ORIGINAL: Rob2007

This plane was actually my first venture into scale and I have clearly made a poor choice, can anybody suggest a good flying warbird for next attempt.

Hisham, I balanced mine as the instructions which was 85mm back from the leading edge and 1800mm out from the centre of the wing, clearly this was way off, I would suggest you contact the manufacturer/distributor to see if this value has been revised.



World Models .46 and .60 size Mustangs fly very nice.

BTW, the yellow .46 size Mustang looks BAD in the advertisements on the Web, but in the air, looks the BEST by far, in my opinion.. It really stands out. The .60 size has flaps and flies bigger and is more forgiving.

This is assuming you are ready for a Warbird.

Bill

(in reply to Rob2007)
       Post #: 9

RE: CMPro P-51 (50 size) test flight crash - 10/28/2007 6:59:10 AM   
jeffk464


 

Posts: 1239
Joined: 10/31/2004
From: cerritos, CA, USA
Status: offline 		If you wait till december you can get the new top flight 60 arf mustang. It will be the best flying, best looking small mustang out by a long shot.

(in reply to Billville)
       Post #: 10

RE: CMPro P-51 (50 size) test flight crash - 10/30/2007 10:10:43 PM   
Norm Nestie



Posts: 374
Joined: 4/28/2002
From: Gabriola Island, BC, CANADA
Status: offline
quote:

ORIGINAL: Rob2007

This plane was actually my first venture into scale and I have clearly made a poor choice, can anybody suggest a good flying warbird for next attempt.



Now getting passionate about warbirds and am building the TF Spitfire but in the meantime have been flying a Richmodel Spit arf from AK Models. Looks not bad and is a GREAT flying plane.


(in reply to Rob2007)
       Post #: 11

RE: CMPro P-51 (50 size) test flight crash - 10/30/2007 10:49:07 PM   
jmohn


 

Posts: 638
Joined: 7/5/2007
From: San Jose, CA, USA
Status: offline 		The CMPs are a little heavier than other models. If you get the CG right they fly fine, just don't slow down too much on your approach. I have had several and like the bigger Hellcat and zero the best so far. The P40 was a fast and unforgiving plane and needed a lot of speed to land nicely. You may want to try a Hanger 9 or Top Flight P51 as they are lighter and have more wing. As far as scale goes the CMPs are hard to beat!

Sorry about your loss! My P40 burned up in flight


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       Post #: 12

RE: CMPro P-51 (50 size) test flight crash - 10/31/2007 12:21:02 AM   
SCALECRAFT


 

Posts: 1320
Joined: 1/7/2002
From: MONTEBELLO, CA, USA
Status: offline 		Hi

If you have the CMP 54" span one, I have a Magnum 52 in mine with around a four ounce brass prop nut . With my cg location, its a very forgiving and docile version of the P-51D.

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(in reply to jmohn)
       Post #: 13

RE: CMPro P-51 (50 size) test flight crash - 10/31/2007 12:28:49 AM   
SCALECRAFT


 

Posts: 1320
Joined: 1/7/2002
From: MONTEBELLO, CA, USA
Status: offline 		A pic of my Cg location. Retracts retracted and model inverted. No fuel.

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(in reply to jmohn)