Top Flite Giant Zero 86" Span.
07-10-2016, 02:57 PM
#376
Something must have changed. I've got 2 of the big P-47's, 2 of the big P-40's, and 1 of the big F4-U's. They are all pneumatic, range from 4 years to six months old and have never had a problem except for pinched air lines and 1 leaky cylinder.
I'll cautiously say most all the landing have been fairly smooth and none of them have bent anything. Did the metallurgy change recently? Is it the electrics having these problems? There has to be more to the story.
I'll cautiously say most all the landing have been fairly smooth and none of them have bent anything. Did the metallurgy change recently? Is it the electrics having these problems? There has to be more to the story.
07-10-2016, 05:15 PM
#377
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Well, I guess one thing, if the pins were stronger the load would be transferred to another part of the construction. Mine was not a smooth landing so I have to take some responsibility, but I just thought it would be a little stronger. Well.... nothings perfect!!
07-10-2016, 05:52 PM
#378
Lots of people are landing gently and do a slight turn off the runway towards the end of the rollout and the pins are bending even with that slight amount of pressure. If that's the case about damaging the wing, make them like BVM. Super strong gear and then flex plates that can be replaced easily.
07-11-2016, 04:00 PM
#379
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I straightened out the bent pin this morning. It returned to its original position very easily. That fact, along with the saw marks evident on the cut end of the pin suggest that this material is really quite soft.
I will fly again, and if it bends easily I think I will grind off the weld, punch out the pin, select the correct diameter drill, weld that in and cut off to length. I think drill steel will be a better temper, and will be easy to get the perfect diameter.
I will fly again, and if it bends easily I think I will grind off the weld, punch out the pin, select the correct diameter drill, weld that in and cut off to length. I think drill steel will be a better temper, and will be easy to get the perfect diameter.
07-12-2016, 06:22 AM
#381
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I have fixed 3 of them for friends and have used 1/4 dia. hardened steel dowel pins. 2 years and lots of landings they are holding up great. 90% of the landings on grass.
I have done this for the P-47 & FW-190.
I have done this for the P-47 & FW-190.
07-12-2016, 08:27 AM
#382
Same thing's going on with all the TF planes using Robart gear.
i started this previously but not much of a response over in the Jet forum but relates to Warbirds directly.
http://www.rcuniverse.com/forum/rc-j...-retracts.html
i started this previously but not much of a response over in the Jet forum but relates to Warbirds directly.
http://www.rcuniverse.com/forum/rc-j...-retracts.html
07-13-2016, 04:41 PM
#384
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Sorry, no picture from me, I have already re-assembled my retract. This link at the Robart site should show a picture of the trunnion and the pins are easy to see.http://robart.com/collections/retrac...union-assembly
07-24-2016, 11:24 AM
#385
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And.... got to fly the TF Zero for a second time. Airframe flies beautifully, slowed her down good before deploying flap, absolutely not a problem. Landed pretty well, not perfect but all observers felt it was a pretty good one. Sure enough one of the landing gears is not fully extended (the other side from last time, RH side this time). So, that was flying for the day. Went home, pulled the gear apart, same issue as before, bent pin. So......confirmed in my mind, these pins are not up to the job at all. Have now stripped the gear and will replace all of the pins.
Nice one Robart....
Nice one Robart....
07-24-2016, 11:47 AM
#386
My TF Zero is in the process of getting a glass and epoxy job and eventual paint. Will be doing a light gray (A6M3ish) scheme. From my research, most of the Navy Zekes that were this color (some like to say white) were early A6M2s that had a shorter cowl compared to the later ones like our model has.
When it came to the Robart gear, I've heard this story over and over and over ad nausium! I bought a set of Sierra Giant Scale gear and they are an absolute work of machining art! Thought about converting them to electric, but have decided to keep them pneumatic. Can't wait to complete this baby!
I think it just sucks what you guys are going through with these Robarts. Gear is a significant cost of the final airframe and to be having such trouble with a measly part of the gear, to me, shows a poor design feature. I know Robart says that if they built them more bullet proof, then guys would be ripping them out of wings left and right. Well, I don't know about that, but there HAS TO BE a happy place between the two extremes!
Good luck guys!
When it came to the Robart gear, I've heard this story over and over and over ad nausium! I bought a set of Sierra Giant Scale gear and they are an absolute work of machining art! Thought about converting them to electric, but have decided to keep them pneumatic. Can't wait to complete this baby!
I think it just sucks what you guys are going through with these Robarts. Gear is a significant cost of the final airframe and to be having such trouble with a measly part of the gear, to me, shows a poor design feature. I know Robart says that if they built them more bullet proof, then guys would be ripping them out of wings left and right. Well, I don't know about that, but there HAS TO BE a happy place between the two extremes!
Good luck guys!
07-24-2016, 01:19 PM
#387
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Someone posted a video of my flight on another forum. Here it is, yes.... landing was not perfect, a little fast, only half-flap.
https://youtu.be/17fbIf8eY5g
https://youtu.be/17fbIf8eY5g
07-24-2016, 01:39 PM
#388
That wasn't a BAD landing by any means. Yes, just a little fast and a little drop on the touchdown. These things have to be able to withstand something less than a perfect landing every time. That's really unfortunate!
09-14-2016, 11:34 AM
#389
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And she's a gonner!!! After much criticism for coming in too high and too fast ( mostly criticized by those who fly foam gliders!!!) I came in slow and low. Dropped a wing without warning and in she went. Our field is a bit challenging as you have to clear some trees that stand about 30 meters short of the runway. Then you can drop the nose some, but still have to clear a 7-wire fence before you are clear to land. As a result the landing profile is not a long gentle descent with easy speed management, rather a drop in from height and then a flare, and you need to be touching down fairly early lest you run out of runway.
This said, I have been flying there for 3 years now, and have successfully landed many warbirds and other types of model.
I had full flaps, these were less than the recommended full flap stated in the manual. It really caught me by surprise as there hadn't been any tendency to drop a wing before. I did 3 slow circuits with flap down before attempting to land. Observers were also surprised as they felt (as I did) that I was carrying enough airspeed.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
This said, I have been flying there for 3 years now, and have successfully landed many warbirds and other types of model.
I had full flaps, these were less than the recommended full flap stated in the manual. It really caught me by surprise as there hadn't been any tendency to drop a wing before. I did 3 slow circuits with flap down before attempting to land. Observers were also surprised as they felt (as I did) that I was carrying enough airspeed.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
09-14-2016, 12:51 PM
#390
And she's a gonner!!! After much criticism for coming in too high and too fast ( mostly criticized by those who fly foam gliders!!!) I came in slow and low. Dropped a wing without warning and in she went. Our field is a bit challenging as you have to clear some trees that stand about 30 meters short of the runway. Then you can drop the nose some, but still have to clear a 7-wire fence before you are clear to land. As a result the landing profile is not a long gentle descent with easy speed management, rather a drop in from height and then a flare, and you need to be touching down fairly early lest you run out of runway.
This said, I have been flying there for 3 years now, and have successfully landed many warbirds and other types of model.
I had full flaps, these were less than the recommended full flap stated in the manual. It really caught me by surprise as there hadn't been any tendency to drop a wing before. I did 3 slow circuits with flap down before attempting to land. Observers were also surprised as they felt (as I did) that I was carrying enough airspeed.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
This said, I have been flying there for 3 years now, and have successfully landed many warbirds and other types of model.
I had full flaps, these were less than the recommended full flap stated in the manual. It really caught me by surprise as there hadn't been any tendency to drop a wing before. I did 3 slow circuits with flap down before attempting to land. Observers were also surprised as they felt (as I did) that I was carrying enough airspeed.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
Sorry to hear. It kinda comes with hobby you fly long enough it is bound to happen.
09-15-2016, 07:49 AM
#395
And she's a gonner!!! After much criticism for coming in too high and too fast ( mostly criticized by those who fly foam gliders!!!) I came in slow and low. Dropped a wing without warning and in she went.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
Oh well. I hope my Saito radial is recoverable, it looks a bit worse for wear!! Maybe I'll build another one of these end of next year when I have saved some funds. It flew beautifully up until this occurrence.
09-15-2016, 01:20 PM
#396
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Yeah, the stall really took me by surprise, the model had been rock-steady throughout the flight and during the slow speed circuits. My thinking is that it is a better approach with half-flap, full-flap seems to slow it down too much even when the full-flap setting is quite a bit less than the figures published in the manual.
Will probably do another Zero if the motor checks out or is repairable. The initial damage appears to be a munched (for want of a better word) tappet cover on No. 1 cylinder and the header pipe from the Keleo exhaust to No.1 cylinder is wrecked. More than that I haven't ascertained yet. Am worried because it impacted with power on, as soon as the wing dropped I chucked the throttle forward as the only response possible to gain airflow over the wings ( not enough height to drop the nose and gain airspeed), the motor was spooling up when it went in. Didn't achieve full power (might have pulled out if it had) but certainly some shock will have been imparted through the engine as it was running a carbon fibre propeller which is now smashed and delaminated.
One thing that seems to have escaped damage is the landing gear (which was down at the time). Because the model rolled in on it's back the underside of the model was mostly unscathed. Funny, still don't know if the modifications to the main landing gears have been effective ( the replacement of the soft pins) as it hasn't been landed since!!
Will probably do another Zero if the motor checks out or is repairable. The initial damage appears to be a munched (for want of a better word) tappet cover on No. 1 cylinder and the header pipe from the Keleo exhaust to No.1 cylinder is wrecked. More than that I haven't ascertained yet. Am worried because it impacted with power on, as soon as the wing dropped I chucked the throttle forward as the only response possible to gain airflow over the wings ( not enough height to drop the nose and gain airspeed), the motor was spooling up when it went in. Didn't achieve full power (might have pulled out if it had) but certainly some shock will have been imparted through the engine as it was running a carbon fibre propeller which is now smashed and delaminated.
One thing that seems to have escaped damage is the landing gear (which was down at the time). Because the model rolled in on it's back the underside of the model was mostly unscathed. Funny, still don't know if the modifications to the main landing gears have been effective ( the replacement of the soft pins) as it hasn't been landed since!!