ParkZone P51 : Dead on day 2 - RC Groups
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May 31, 2005, 01:26 AM
Must... go... faster...

ParkZone P51 : Dead on day 2

I bought a P51 yesterday. I opened it like a kid at christmas, assembled it and charged up the battery. It was a bit windy outside, so I didn't fly it much, but got it in the air long enough to trim it and be happy with my purchase. The thing is a bugger to throw, but it launches well and flies really nicely.

This morning was calm day, so it took it to the field expecting to get some good "real" flight time where I got to play around a little. I had it in the sky all of about 3 minutes. I did a barrel roll, and came out of it with the nose down a little. While pulling out of the dive (and not very hard) about 80 ft up, the battery ejected from the model. I watched in horror as the model did a slow, spiralling nose dive into the ground, shattering the cowl and spinner, creasing the fuselage, and separating the main wing, pilot, and canopy from the fuse.

I walked over to the plane and surveyed the damage, and then went looking for the battery, which I spotted about 30 feet from the plane. I bent over to pick it up, and got a nice burn on my thumb for my trouble. It was then I noticed the connector sitting about 5 feet from the battery, and saw that the battery leads had fused together and the shrink wrapping was melting away. The battery began to smoke, and I quickly moved away. About 10 seconds later, a cell in the battery exploded.

Having done a little reading online now, I've found that the battery cover has let go for several people. Since the plane is so new, I thought I'd post a warning for people either not to buy the plane until this flaw is fixed, or to make sure you know to secure the battery hatch yourself.

I like ParkZone's stuff, and would like to continue to be a customer of theirs - I have a J3 Cub that my wife gave me which got me started. I've since bought a Stryker, too, and I've been extremely happy with both. After this though, I'm a bit soured on their stuff - I have a hard time believing that during all their testing, no one ever encountered a problem with this battery hatch. I noticed while assembling the plane that it was in an odd spot for a hatch with a simple plastic clip. My J3 Cub has the battery hatch in the same place, and even though it's designed for non-aggressive flying, it's got a latch to hold the battery cover in place. I can't imagine why they didn't think to add such a thing to the P51 as well. Hopefully they'll step up and correct the problem.

I've sent an email to Hobby Zone, and will post updates here for anyone interested.

Jason Dorie
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May 31, 2005, 02:12 AM
Keep building, buying,fly
Bigplumbs's Avatar
Sorry to hear of you problem Jason. Don't give up on Parkzone. Is the plane repairable ?
May 31, 2005, 02:31 AM
Must... go... faster...
Repairable with new parts. Structurally it looks ok, so it'd probably fly if I reassembled it, but I need at least a new battery. The cowl and spinner were shattered in the crash, but that's probably more cosmetic than structural. The battery hatch is cracked too, so I'd need another of those, though I'd probably find another way to secure the battery regardless.

As for ParkZone, I haven't given up on them. I sent them a mail and will see what their response is. As far as I'm concerned, they owe me a battery & cover, cowl, and spinner at the very least, and I've told them so. If they replace those, they have me as a customer again. If they are also willing to replace the creased fuse and wing, they'd have a very happy customer. If they design a better way to secure the battery on this plane, I'd go so far as to consider them a responsible company.

May 31, 2005, 03:33 AM
Registered User
LTChip's Avatar
Oh man! Battery ejection is about the worst thing an EP plane can experience! Sorry to hear about your crash.

Let us know how PZ treats you.
May 31, 2005, 06:58 AM
Purdue Engineering
Rocketman1092's Avatar
The battery on my TM got so hot the covering melted off! I covered it in electrical tape and cut a large cooling channel for it, and it isn't causing any further problems. By the way, what battery were you using when your plane crashed?
May 31, 2005, 08:39 AM
Registered User
Ed Couch's Avatar
I flew the P-51 several times this weekend that belonged to the local hobby shop for demo purposes and to get my response on the aircraft and found the aircraft to be an excellent flyer except for being a little loose or soft on the elevator. Over the last 40 years of r/c flying every Tang I have ever flown has been the same way due to its small horizontal. Other than that it flew just fine. One thing I did notice was how hard it was to get the battery pack out of the aircraft. The tab had been broken off of the plate and it was a bear to get the plate off and on and I honestly don't see the battery falling out if it was latched in position. I had to use a screwdriver to pry the plate off each time I flew it. I hooked the battery up after sliding the battery into place and there is just no way that the thing could fall out. I talked to one of the other pilots who had flown the test bird the day before and he had connected the battery and slid it in butt first with the point of the pack down but had a hard time of removing the battery when finished. By your discussion it would appear that the latch may not have been snapped in tight allowing the battery to seperate the vehicle on a high G maneuver. Also, the battery connector latch normally would not allow the battery to fall free. The pack I refer to is the stock 9 cell 1000 mah pack included in the basic package. Its a bummer for sure when you loose a new bird. Been there and done that more times than I hate to admit to and many times it was my own dang fault. I've flown all the parkzone birds released and must admit that they all fly well but to me this bird is a little too much for the radio utilized in the package. It flies like the old radios used 35 years ago (servos too slow). For a fighter type aircraft the controls can be referred to as sloppy, radio better utilized in trainer type aircraft. This little bird will bite even an experienced pilot who gets a little lazy let along an inexperienced shooter with a bad case of the P-51 syndrome. An boy did I miss the rudder on a scale type bird. God put it on the aircraft for a reason. Love to have the airframe/motor without the radio for about 70 bucks. ed
Last edited by Ed Couch; May 31, 2005 at 08:46 AM.
May 31, 2005, 10:17 AM
I love the smell of 100LL
monitor's Avatar
I had a similar battery ejection, but I guess I was lucky because the plane "landed" in the top of a tree with only minor damage to the elevator that was recieved as it tumbled through the branches on the way down.

From a small part of the battery hatch that I found...... it looks like the hatch broke at the latching point.....

I wonder if I should email parkzone about this. I never thought that it might be a warranty issue.
May 31, 2005, 10:34 AM
Well, now that you know ...
Bigster's Avatar
Same problem with a parkzone battery this weekend. Battery ejected from the plane (HZ Commander) on landing/impact - connector stayed, battery departed. Leads touched, wires melted. No explosion, so I 'm hoping to replace the connector and see if it'll take a charge.
May 31, 2005, 12:37 PM
Must... go... faster...
Rocketman: I was using the battery it came with, the stock 9 cell 10.8V 1000mAh.

Ed : It wasn't my fault - I had similar difficulty getting the hatch off myself, but I was very careful to seat it properly. I put the battery in connector first, single cell pointing down. The hatch now has two small white stress marks and a small crack near the rear of the hatch, not the front clip side that takes the stress of removal (check out the attached pics). If you look closely at the 2nd pic, there's light stress whitening near the main clip that would be from removing / inserting the battery - I put all the stress on the front clip. The rear stress lines are the ones I don't get - I don't see how that could've been my fault.
May 31, 2005, 01:07 PM
Registered User
Ed Couch's Avatar
Jason, does the battery pack slide in easily or do you have to push it in with some force? The bird I was flying it had to be forced in as it seems too fit only one way and by connecting the battery after it was inserted there was not enough slack in the cable left to allow the battery to fall out of the aircraft. I see your photos of the damage to the battery plate and agree that it should have not been damaged at this early date. When reviewing data I always look for the most probable cause of failure and what I'm seeing so far especially with more than one shooter having the same problem is that the hatch design is a problem and battery installation procedures would be in question. I would have to say add a #64 rubber band around the bird and over the hatch as a safety fallback. I don't remember in reading the manual what it calls out as the proper installation procedure. Somebody please review the booklet for me and refresh this old farts memory. No real suggestion of blame only just basically asking questions.

May 31, 2005, 01:21 PM
Must... go... faster...
I had to install the battery "connector first", and yes, it required a bit of force to get it into the fuselage, mainly because of a slight bulge under the shrink wrapping where the wires connected to the cells. Once past that bulge, it slid in easily.

The manual just says "plug the battery into the connector inside the fuse, then secure the battery inside the fuse and replace the battery cap." I was on day two, so still on the honeymoon, and being quite careful.
May 31, 2005, 01:58 PM
Vintauri's Avatar
My battery is snug to get through the opening but is loose inside the cavity. Only two ways I see this happening. First is with a really weak battery hatch and a strong positive g force. The other is putting the hatch on backwards. The clip must be to the front or the hatch fits really loose and can come off.

I would not mind having about 1 more inch on the power leads from the ESC to make plugging in the battery easier.
May 31, 2005, 01:59 PM
I love the smell of 100LL
monitor's Avatar
Huh ok now this is starting to make sense. I could only find part of my battery hatch after my incident this weekend. It looks like that part to the "left" of the first picture.... between the white stress marks and the edge of the hatch.

I have ordered 2 more hatches, and plan to have a rubber band as a backup from now on. Any one have any suggestions on painting a rubber band to match the fuselage?
May 31, 2005, 02:06 PM
Vintauri's Avatar
well I have colored rubberbands with sharpies before. THey make silver and possibally green. But I think the sharpie eats into the life of the rubberband.
May 31, 2005, 02:15 PM
Registered User
T-Fly's Avatar
I'm sorry that these battery ejections are happening, I'm just glad that you guys are posting it so that when I buy mine I can take the measured steps to keep it from happening to me. Just wish I would have known that the battery hatch for the Stryker was so terrible before I launched a battery out of it.

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