FMS P51 Crash

[TexasPilot71]

Well, I did it. Nose-first dive into the turf. Really wasn't my fault. Or was it?

Third flight of the evening and after takeoff and a couple maneuvers she failed to respond instead spiraling vertically into the ground. Got to "the scene" and did some investigation. All control surfaces that were still plugged in worked normally. The elevator and the rudder had become unplugged, but the rudder worked just fine after plugging it back in. The elevator servo, however had become tangled in a servo wire. After freeing the wire and plugging the servo back in, it worked normally. Check out the pics.

Looks like a clean break...everything still works and besides some aesthetic damage it should go back together nicely. What kind of glue would you all recommend and are there any tips for repairing my beautiful Mustang?

Enjoy the pics:

[OV10]

RE: FMS P51 Crash

Hello Tex,
It's a sad affair when a pilot has a loss but the important thing is too learn from the mistake. From the pics you posted, I would have to conclude that your assembly was the culprit of the crash by virtue of a servo wire caught up a servo arm which most likely disabled one of your controls. I maiden a lot of birds at our club for novice pilots and one of the biggest issues that I see during the preflight of the airframe is what I call the wire rats nest. It is very important that all wires are securely positioned away from all control linkages EVERYTIME the bird is put together.
The best adhesive that I would recommend is the white(1 hr) Gorilla glue. It's expansion capabilities of 2-3 times is most excellent for getting into all those nooks and crannies of foam. It's expansion can be controlled with blue painters tape on the seam line of the joint repair area. Any excess can be easily carved away after it has cured.
I see that the frontend looks to be pretty much toast also besides the fuse being snapped in half. You may want to seriously consider procuring a new fuselage at a modest $50 replacement cost just for ease of mind that your getting a fully integral airframe back in the air and use the wreckage as a practice piece if you've never done any major foam repairs before.
Best of luck,    

[TexasPilot71]

RE: FMS P51 Crash

Hello Tex,
It's a sad affair when a pilot has a loss but the important thing is too learn from the mistake. From the pics you posted, I would have to conclude that your assembly was the culprit of the crash by virtue of a servo wire caught up a servo arm which most likely disabled one of your controls. I maiden a lot of birds at our club for novice pilots and one of the biggest issues that I see during the preflight of the airframe is what I call the wire rats nest. It is very important that all wires are securely positioned away from all control linkages EVERYTIME the bird is put together.
The best adhesive that I would recommend is the white(1 hr) Gorilla glue. It's expansion capabilities of 2-3 times is most excellent for getting into all those nooks and crannies of foam. It's expansion can be controlled with blue painters tape on the seam line of the joint repair area. Any excess can be easily carved away after it has cured.
I see that the frontend looks to be pretty much toast also besides the fuse being snapped in half. You may want to seriously consider procuring a new fuselage at a modest $50 replacement cost just for ease of mind that your getting a fully integral airframe back in the air and use the wreckage as a practice piece if you've never done any major foam repairs before.
Best of luck,    

Thanks, Charlie! I completely agree and have learned in regards to wire management. There is SO MUCH wiring, though. I'll have to play with that after the repair.

Upon further examination, the bird is actually in really good shape. It's easier to list the things that broke than what is working. I'll say this, the replacement fuselage isn't in stock and I noticed it was out of stock a week or two ago as well. But it's a pretty clean break. With some carbon fiber and/or small dowels and gorilla glue, I think it will be (almost) good as new. The cowling needs replaced, need a new spinner and back plate, and one of the the oil tanks is toast, but all the electrics work fine, the gear doors are fine, and even the motor mount is good. Not even a prop is damaged!

Quick question...I noticed the motor is mounted cocked to the right (maybe 5 degrees?). I presume this is normal to compensate for p-factor and torque. Can you confirm this is correct?

Many thanks for the reply!

[OV10]

RE: FMS P51 Crash

Tex,
Your assumption is correct about the motor mount/motor board being installed with a down/right pitch to counter act the p-factor/torque.
What you really need to do in this area is carefully assess if the plastic motor board assembly(part that the metal X-brace motor mount attaches to) that is buried in the foam has not been moved by virtue of foam compression because of the nose first whack.
I did didn't see any of these motor mount parts listed under the Snoot's Sniper parts section but you can find them in the Dallas Darlings parts because they are all the same if you need to replace them. http://www.motionrc.com/fms-1400mm-p51b-dallas-darling/?sort=featured&page=1
Good luck with the repair,

[TexasPilot71]

RE: FMS P51 Crash

Thanks, again, Charlie. It looks like the motor board survived. I'll take a closer look to be sure. Just picked up some carbon fiber rods and epoxy at our local hobby shop. They showed me how to repair it and it looks like a very straight-forward fix.

[RCcruz]

RE: FMS P51 Crash

Ouch , hope she's gets flying again. I would also check the quick disconnects on the wings were they join . I had replaced them 2-3 times due to jittery servos or one wing does not respond . The junction box were all wires connected too @ the wing/wings the wires will break off or loosen. Happens to me due too transport from home and then to flying feild. Usually it's the negative wire on the junction boxes come loose . Any way happy FLIGHTs when fixed

[Hippie 64]

RE: FMS P51 Crash

Texaspilot I really hate that one ! I would almost be boohooing.... 

Not sure but I may have missed it , for me as a rule I always tie my wires together. Tie wrap or bread tie then a little hot glue will help to secure them to the fuselage. 

Just a thought ....
Good luck and keep us informed 

Bryan 

[Alpha]

RE: FMS P51 Crash

2mm zip ties are what I use most often to manage wires. Aircraft which have all the "bells and whistles" can have much more wire to worry about that a more simply four channel aircraft.

I'm glad to see at least that yours was a clean break across the fuselage. Two part epoxy and bamboo skewers or carbon rod will make for a lightweight and sturdy fix.

Do not adjust the motor mount's built in thrust angle, that is normal for just about every single propeller driven aircraft on our website, and the amount of down thrust varies per product and accordingly is determined by the manufacturer and designed into the aircraft.

Hope to see you flying again soon!

[Gas1313]

RE: FMS P51 Crash

Thanks, again, Charlie.  It looks like the motor board survived.  I'll take a closer look to be sure.  Just picked up some carbon fiber rods and epoxy at our local hobby shop.  They showed me how to repair it and it looks like a very straight-forward fix.

I recommend putting in carbon fiber rods from killer planes I've crashed mine at 175 feet up nothing broke except the nosecone and prop. They tell you how to put it in and everything. I will not fly without it. Talk to Denise about a reinforcement kit for the P 51. You will be glad you have it for reasons like yours. Hope everything works out. Pete

[TexasPilot71]

RE: FMS P51 Crash

Wow, you guys are great!! Thank you for the tips!! Fuse is back together with epoxy. Adding the carbon fiber rods next. P51 reinforcement kit? I'll have to find out more about that.

[TexasPilot71]

RE: FMS P51 Crash

Repairs coming along nicely. Going to have to clean up some of the paint, though. Notice I re-routed the suspect servo wire. I'll also zip tie them together and put some hot glue down to keep them in their place. New cowling installed, original exhaust and vents epoxied back together. Found one retract was slipping its gears, so ordered a new one. Got new drop tanks too, but that will about wrap it up. I'll post a couple more photos when complete and BEFORE it's post-repair maiden. LOL! Thanks again for all the advice and help!

[Hippie 64]

RE: FMS P51 Crash

Repairs are coming along nicely! You'll be back in the airin no time .

Good luck !!

Bryan

[Grossman56]

RE: FMS P51 Crash

Wow, great job Tex, a little filler and some paint and you're as good as new.  Don't you just hate that when you have something like that go wrong.  Just went through the same thing with my Old Crow all over something that could have been easily prevented.  In my case I left the gyro switch on when I hadn't proof flown it. turns out that the ailerons were correcting the wrong way. 
So, I added that to the preflight list.
Your incident brings up a good point as well to check all connections before flight, hey, gives us something to do the night before!

Grossman56 

[Pheonix]

RE: FMS P51 Crash

Oh how true. I went to take off yesterday with full throttle, pulled on the elevator and nothing happened. Come to find out, a wire was loose enough that there was little contact. Fixed this problem and was off and flying. I have a check list now to and will use it!

[Capt. Crunch]

RE: FMS P51 Crash

Nice job on the repair TexasP. Its amazing how much abuse these foamys can take, and still get them back in the air

Jeff

[TexasPilot71]

RE: FMS P51 Crash

Thanks again! She's all mated with her wings again, motor re-mounted and props and spinner attached. I replaced the landing gear "casings" with the metal ones from CNC. When I went to test, I found the gear not moving. I thought I had tightened the casing too tight and restricted movement. But even when I removed it, the jack screw would slip with any amount of resistance applied. I think the internal gears (probably plastic) were stripped. So I ordered a new retract and as soon as I receive it, she should be airworthy again. Just need a little aesthetic work and we'll be back in business.

[Grossman56]

RE: FMS P51 Crash

Sounds good Tex, just remember to CG it again.
You'll love the retract casings.  The first one I did I had to play around with to get everything into the right position, but once learned, it was pretty easy and they are an excellent step in the right direction.
Sounds like you're pretty close to a flight again, its satisfying to have come from a major to complete repair and in the air!!

Grossman56

[TexasPilot71]

RE: FMS P51 Crash

Well, here she is. All ready for post-crash maiden.

Before flight:


And after:

[hr]
I am so fed up with this. It appears I lost rx/tx connection. Using a DX6 with a healthy set of batteries and a "true" Spektrum receiver. Purchased new and flown on this airplane several times before the first crash. There's only one other thing I did before the first crash and that was change out the motor which went bad (magnets came un-glued). I think I'm done with this hobby :(

http://youtu.be/tn8MjPMG-0c

[XF-15DCC]

RE: FMS P51 Crash

Ouch,
Sorry for your loss, think it can be rebuilt one more time?

Now I'm no expert but as I have been talking with folks about getting a better radio system, I'm finding mixed feelings with Spectrum. (NOT SLINGING MUD) and have talked with a few pilots that have had the same thing happen to them.

Kevin.

[Grossman56]

RE: FMS P51 Crash

Geez Tex, that's just so wrong!?

I don't know what it is about Snoots Sniper, Stoopid Monkey (Sean Byington) had the same plane and the same results.  I have the Shangila version and have had good success with it, with Spektrum gear.  As a matter of fact, eight of  nine of my planes use Spektrum receivers, the two others being trainers.  I'm thinking maybe a control rod got hung up? somehow got out of range, although it doesn't look like that was the case.  Was the motor still turning over?
Man, its a real mystery...
All I can think of is that if you repair, do a range check.  You should get 6 minutes of average flying easily on a 3600 4S battery.  Do a cell check on it and brand new AA's in the DX 6i, wish I could offer more..

Grossman56