Lawn Dart
04-21-2009, 10:39 PM
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Lawn Dart
So I've been a member of this forum for a while now but just haven't been actively involved in the posts. I recently got back into the RC plane scene after a few years away from the hobby. (I am no longer a poor college student...I finally finished and can now finance my hobbies more effectively). Anyway I was out flying a bigstick the other day and I did a quick pull up to vertical from a horizontal line and I heard a god awful sound (I thought my prop had shattered and the engine RPM's surged). I immediately chopped the throttle when this happened. The nose of the plane was pointed perfectly vertical maybe 100ft up. When I chopped the throttle and the plane nosed over I saw something flutter away from the plane. I realized it was the horizontal stabilizer....and watched in awe as it nose planted. Pretty good carnage. You will notice the rudder is missing too. I believe it sheared off at impact. The shock from the impact basically vaporized some of the wing ribs and blew the covering apart. The engine turned out okay as far as I can tell aside from the adjustment needle breaking off the backplate which has already been jb welded back in place. As far as the airframe goes it is a total loss. Still need to test the servos and receiver. When I decided to get back into rc planes I bought a "lot" of planes and equipment from a guy which included this bigstik as well as another one which was identical to it with the exception of some built in dihedral. I started back flying the dihedral version to get comfortable again and have since progressed to many other planes. The dihedral bigstik met it's demise when the wing ripped off in flight. I had been doing some pretty demanding high G maneuvers with this one prior to the stabilizer failing. It is definitely a shame though as this one tracked very well and had the perfect amount of power. Oh well....it was fun while it lasted!!
Oh and the little kid in the pictures is my neighbor who always shows up when he hears one of the planes running.... About 30 seconds after the crash he was asking if he could have the remains
Oh and the little kid in the pictures is my neighbor who always shows up when he hears one of the planes running.... About 30 seconds after the crash he was asking if he could have the remains
04-22-2009, 11:57 AM
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RE: Lawn Dart
I will definitely pass on the remains to him. I just got a trainer setup so one day maybe I could get him flying safely. His attention span is a bit short though so we'll see. Also I have never met his parents so they may not appreciate me getting him into an "expensive hobby" I do not think there is any hope for repair. I will strip off the wing covering to see how bad it truly is. If the wing is salvageable I may repair it and hold on to it for future use. Since I have been back into this I have had this most recent crash and a wing come off of another bigstik. Both total losses. I have had one other crash with a .25 size slowcub which I am not 100% certain of the cause. I rolled it inverted quite a distance away and went to do a 180 degree reverse/half loop to come back toward me and on the downline the thing went into a spiral and appeared to be unresponsive. Best I can tell it came down at about a 70 degree angle through the top of a tree. Pieces were pretty well scattered. The RX batt had a good charge. I noticed one of the aileron control horns was broken off at the base so I am unsure if it was related to that or if it was a receiver range problem. I was unwisely using a spektrum 6 channel parkflyer receiver. I am not sure if it was a range issue or not though because I had it further out on other days with no problems. Oh well.... As far as the bigstiks go, I guess I learned my lesson about over stressing an airframe. I'll try to post some pics of the slowcub later as well. It was pretty impressive. The kid did end up with the cub remains
04-22-2009, 03:35 PM
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RE: Lawn Dart
if i was you, i would test some of your stuff.
it could be pilot error, electronic,ect
or it could be this guy's planes just poorly built.
if two planes went down for a unexplainable reason i would be suspicious.
that being said,
if their was a lawn dart compition i would give you a 10 out of 10.
that thing went strait in.
it could be pilot error, electronic,ect
or it could be this guy's planes just poorly built.
if two planes went down for a unexplainable reason i would be suspicious.
that being said,
if their was a lawn dart compition i would give you a 10 out of 10.
that thing went strait in.
04-22-2009, 04:18 PM
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RE: Lawn Dart
You shoud but a cross there as a memoral for your plane, heck you alreay have nice hole in the gound lol, here lays "big red" she was a good plane untill she decided to fall apart in midair. Then roll over and dig her own grave. 
04-22-2009, 05:54 PM
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RE: Lawn Dart
if i was you, i would test some of your stuff.
it could be pilot error, electronic,ect
or it could be this guy's planes just poorly built.
if two planes went down for a unexplainable reason i would be suspicious.
that being said,
if their was a lawn dart compition i would give you a 10 out of 10.
that thing went strait in.
it could be pilot error, electronic,ect
or it could be this guy's planes just poorly built.
if two planes went down for a unexplainable reason i would be suspicious.
that being said,
if their was a lawn dart compition i would give you a 10 out of 10.
that thing went strait in.
The first bigstik the wing came off of was likely due to issues prior to my receiving the plane. It had been crashed and repaired before and the bulkhead that the front wing dowels plugged into had been broken. I believe the epoxy joint failed allowing air to pull the leading edge of the wing up and ripping the wing bolts and block out at the trailing edge. It was pretty impressive as well as it was quite a bit higher than the most recent one. unfortunately it did not impale itself into the ground. It just exploded the foreward fuselage. The wing fluttered down essentially undamaged. Even though this was likely related to previous crash damage I should have caught it before it happened. It only failed after I got comfortable with flying a basic pattern again and began doing loops and rolls etc. It came off at the bottom of a loop.
I am getting fairly comfortable with my flying abilities at this point...all of the planes I have assembled since getting back into the hobby are still in good shape. The only crash I can't explain is the lazy cub that went into an unresponsive spiral. I'm sure that it was likely due to my stupid decision to use a parkflyer rx. Oh well.......
It definitely did go straight in....if I didn't want the engine for future use I would have just left it as a monument
04-22-2009, 07:46 PM
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RE: Lawn Dart
I figured it out, by looking at the photo, the stab seperated because the film covering that was removed to epoxy the stab on was cut too deep and into the wood structure, you'll notice that the wood seperated cleanly, like a knife cut, but the epoxy and wood is still attached to the fuse, just enough that in a high stress manuver, it was the small perferation that pulled the skin of wood off the stab. That is why so many good builders and arf assemblers use hot knives to cut the surface film, not an exacto knife.
04-22-2009, 10:45 PM
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RE: Lawn Dart
ORIGINAL: planebuilder66
I figured it out, by looking at the photo, the stab seperated because the film covering that was removed to epoxy the stab on was cut too deep and into the wood structure, you'll notice that the wood seperated cleanly, like a knife cut, but the epoxy and wood is still attached to the fuse, just enough that in a high stress manuver, it was the small perferation that pulled the skin of wood off the stab. That is why so many good builders and arf assemblers use hot knives to cut the surface film, not an exacto knife.
I figured it out, by looking at the photo, the stab seperated because the film covering that was removed to epoxy the stab on was cut too deep and into the wood structure, you'll notice that the wood seperated cleanly, like a knife cut, but the epoxy and wood is still attached to the fuse, just enough that in a high stress manuver, it was the small perferation that pulled the skin of wood off the stab. That is why so many good builders and arf assemblers use hot knives to cut the surface film, not an exacto knife.
04-23-2009, 07:00 AM
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RE: Lawn Dart
I totally agree about using a hot knife on Monocote.............but your assessment of the cause of the crash is waaaay off!!
If you look at pic#2...you see whats left of the balsa grain for the entire stab area. This is classic separation from over stress/ abuse on a surface. This was an older airframe, and the pilot admitted to a quick pull up to vertical from a horizontal line.
A quick pull up from higher forward speed..on most older airframes..will almost always create this kind of separation!!!
I'm not trying to start a mess here..but the only way you can say that a razor knife was the cause of this crash........was if you were the guy with the knife!!!
If you look at pic#2...you see whats left of the balsa grain for the entire stab area. This is classic separation from over stress/ abuse on a surface. This was an older airframe, and the pilot admitted to a quick pull up to vertical from a horizontal line.
A quick pull up from higher forward speed..on most older airframes..will almost always create this kind of separation!!!
I'm not trying to start a mess here..but the only way you can say that a razor knife was the cause of this crash........was if you were the guy with the knife!!!
04-23-2009, 08:16 AM
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RE: Lawn Dart
ORIGINAL: RC MANIAC119
I totally agree about using a hot knife on Monocote.............but your assessment of the cause of the crash is waaaay off!!
If you look at pic#2...you see whats left of the balsa grain for the entire stab area. This is classic separation from over stress/ abuse on a surface. This was an older airframe, and the pilot admitted to a quick pull up to vertical from a horizontal line.
A quick pull up from higher forward speed..on most older airframes..will almost always create this kind of separation!!!
I'm not trying to start a mess here..but the only way you can say that a razor knife was the cause of this crash........was if you were the guy with the knife!!!
I totally agree about using a hot knife on Monocote.............but your assessment of the cause of the crash is waaaay off!!
If you look at pic#2...you see whats left of the balsa grain for the entire stab area. This is classic separation from over stress/ abuse on a surface. This was an older airframe, and the pilot admitted to a quick pull up to vertical from a horizontal line.
A quick pull up from higher forward speed..on most older airframes..will almost always create this kind of separation!!!
I'm not trying to start a mess here..but the only way you can say that a razor knife was the cause of this crash........was if you were the guy with the knife!!!
Also it was stated that " just enough that in a high stress manuver, it was the small perferation that pulled the skin of wood off the stab " so there was stress involved. Plus the Pilot stated pulling high speed dives :Therefor there where at least three facters that we know contributed ............. My peeny for a pound
04-23-2009, 10:25 AM
#17
RE: Lawn Dart
I use my weller stand iron, it's a 55 watt job, I bought a replacement tip and ground it to a fine line tip. The straight edge works wonders on making smooth cuts, freehand takes some tallent and surgeon hands, otherwise it'll look like you used a plasma cutter to cut the covering.
04-23-2009, 10:40 AM
#18
RE: Lawn Dart
ORIGINAL: planebuilder66
I use my weller stand iron, it's a 55 watt job, I bought a replacement tip and ground it to a fine line tip. The straight edge works wonders on making smooth cuts, freehand takes some tallent and surgeon hands, otherwise it'll look like you used a plasma cutter to cut the covering.
I use my weller stand iron, it's a 55 watt job, I bought a replacement tip and ground it to a fine line tip. The straight edge works wonders on making smooth cuts, freehand takes some tallent and surgeon hands, otherwise it'll look like you used a plasma cutter to cut the covering.
