need advice on installing landing gear
04-26-2014, 07:32 AM
#1
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need advice on installing landing gear
HI guys I am building a 33% extra 300 from a kit and one of my club members suggested i use nylon bolts to hold the gear on in case of a hard landing
I was wondering if nylon bolts would not be strong enough in a normal landing any suggestions?
eddie
I was wondering if nylon bolts would not be strong enough in a normal landing any suggestions?
eddie
04-26-2014, 09:17 AM
#2
My Feedback: (15)
The simple answer to your question is NO. On a model airplane of this size you will shear the bolts and break off your landing gear almost every time...sometimes even on a perfect landing. When landing in the shortest grass-it will come off. You will be the laughing stock in your club. I don't recommend you do that.
04-26-2014, 09:50 AM
#3
Carden secures the landing gear on 40% airplanes with just 6 6-32 screws that simply thread into the landing gear plate. When I saw this I started doing the same. That being said, I would not go with nylon either but setting it up where the screws will pull out of the gear block rather then gear block pulling out of the airplane is a good idea.
04-26-2014, 10:38 AM
#5
My Feedback: (13)
I have a couple planes that I use nylon bolts for the gear not a 33% extra but there holding up just fine after many hard landings,what I did do was when I made the gear mounting plate I used 1/2" hardwood blocks drilled and threaded on the back side of the plate instead of blind nuts to screw into the bolts thread into the blocks much easier and seem to have less stress to the bolt.
when I used blind nuts I was always twisting the nylon bolts which seemed to stress the plastic, the only time I ever had one break was when I crashed in a field and it ended up saving me some repair duty, on a larger plane I would use at least 4 bolts but on my smaller Gizmo I used 3,2 forward, and one in the middle at the rear of the plate I also reinforced the mounting plate with triangle stock so it wouldn't rip out easily and hardened the threads with thin CA in the wood blocks,once tapped I wicked the CA on the threads and when hard I re-tapped the threads
my NEXTAR float plane has 60 size floats mounted with 4 bolts.
and my Gizmo before and after crash pics.
when I used blind nuts I was always twisting the nylon bolts which seemed to stress the plastic, the only time I ever had one break was when I crashed in a field and it ended up saving me some repair duty, on a larger plane I would use at least 4 bolts but on my smaller Gizmo I used 3,2 forward, and one in the middle at the rear of the plate I also reinforced the mounting plate with triangle stock so it wouldn't rip out easily and hardened the threads with thin CA in the wood blocks,once tapped I wicked the CA on the threads and when hard I re-tapped the threads
my NEXTAR float plane has 60 size floats mounted with 4 bolts.
and my Gizmo before and after crash pics.
04-26-2014, 11:39 AM
#6
Don't get me wrong, I have used nylon screws to mount landing gears as well. Mostly on Q500 airplanes. I did use 1/4x20 nylon screws on a Goldgerg Sukhoi once and had them fail rather quickly. I would say the size limit for nylon screws would be a .60 size airplane.
04-26-2014, 12:43 PM
#7
My Feedback: (13)
Don't get me wrong, I have used nylon screws to mount landing gears as well. Mostly on Q500 airplanes. I did use 1/4x20 nylon screws on a Goldgerg Sukhoi once and had them fail rather quickly. I would say the size limit for nylon screws would be a .60 size airplane.
all the bolts I used were the 1/4-20 size, and not the slotted screw head type, the ones with the fat flange and the nut top that has the hole for a allen key
the slotted screws they seem to be weak, there is just not enough plastic on the business end of the bolts for my taste I have had the white slotted screws sheer off before but only on a minor crash but it took a severe thumping to break the black bolts free.
ultimately if you are looking for bullet proof security then a good old 1/4-20 allen bolt threaded into wood or a cap screw will never fail the mounting plate will be gone before that happens
04-27-2014, 04:24 PM
#8
My Feedback: (-1)
I used nylon on a 1/4 scale Extra 300 and they broke off even with a perfect landing. I went over to 4-40 stainless and they never came off again. When the nylon broke and the gear came off the pipes on the muffler broke while skidding along the runway. Last time I used nylon for LG.
04-28-2014, 04:13 AM
#9
I think that the 1/4-20 nylon bolts will sheer if overtightened. I've used them to mount landing gear on giant scale models without incident. If they can hold up to my landings, they should be more than adequate for you guys. LOL
I have noticed, that if I tighten them down as much as possible, they exhibit a stronger tendency to break, than when I just "snug" them down.
Whether a nylon bolt will help to save damage, or create more, is open for debate. I have sheen the nylon bolts sheer under impact, saving the lg mounts from destruction, while at the same time, watching the departed landing gear rip up the bottom of the fuselage as the model continued forward.
Over the years, I have drifted away from using the nylon bolts, but I see no reason that they shouldn't be used.
I have noticed, that if I tighten them down as much as possible, they exhibit a stronger tendency to break, than when I just "snug" them down.
Whether a nylon bolt will help to save damage, or create more, is open for debate. I have sheen the nylon bolts sheer under impact, saving the lg mounts from destruction, while at the same time, watching the departed landing gear rip up the bottom of the fuselage as the model continued forward.
Over the years, I have drifted away from using the nylon bolts, but I see no reason that they shouldn't be used.
