RunRyder RC
WATCH
 1 page 514 views POST REPLY
Home✈️Aircraft🚁HelicopterCentury Radikal G20-30 N640 Hawk Predator › inaccuracy in falcon instructions
01-14-2006 03:50 AM  13 years ago
Topic Vote0Post 1
eagleboard

rrNovice

rio vista ca

MyPosts All Forum Topic
inaccuracy in falcon instructions
well i see the topics are a little stale right now in these winter monthes with this rainy,cloudly weather and all.believe me I WANT TOO FLY.anyway for those who are interested i want to share my century experience.i have just built the falcon 50se v2 with the os 50.i believe there is an inaccuracy on pg.11 of the instruction manual.they say there should be a m3x16 socket cap screw that will go through the lower part of the main shaft to couple the main gear.Wrong.when i built mine the bolt was too short.it wouldnt grab the nylon part of the nut.i went out a got a m3x18 bolt and got the correct lenght.now speaking of this same bolt i have been flying a hawk version 3 for about 6 years now.it uses the m3x16 bolt.i have acually had this bolt snap in flight under heavy load several times.also have had the nut loosen and fall off.saved my bird in autorotation twice out of four.you know when it happens because the motor over revs and theres no positive collective,all you can do is hit the throttle hold and hope you pull the auto off.anyone have any similar situations.
SHARE  PM  EMAIL  Attn:RR  Quote
01-14-2006 03:53 AM  13 years ago
SteveH

rrProfessor

Texas

MyPosts All Forum Topic
Yes,

I've had the same bolt fail on me also...put a much longer bolt in it, one with no threads on the bottom part, and cut it to the proper length, and that eliminated the problem. Now, when I build a new one, I put a long sholder bolt in from the beginning and have had no failures.
The government cannot give you anything without first taking it from someone else.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
01-14-2006 03:59 AM  13 years ago
Al Austria

rrElite Veteran

Sacramento, CA - USA

MyPosts All Forum Topic
You guys are probably overtightening the bolt. That was the case with the Raptor guys as well. No failures here.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
01-14-2006 04:08 AM  13 years ago
eagleboard

rrNovice

rio vista ca

MyPosts All Forum Topic
steve what bolt are you using? on my new falcon 50 v2 i bought the dubro 3mmx18 . it is threaded all the way to to the head
SHARE  PM  EMAIL  Attn:RR  Quote
01-14-2006 06:59 AM  13 years ago
Gearhead

rrMaster

Vt

MyPosts All Forum Topic
what Al said,,, I broke 2 of these bolts, then Phil told me to stop tightening them so much, that was the trick !!

""i have been flying a hawk version 3 for about 6 years"", cool, so you found the Hawk to fly well enough and hold up well enough to the point that you desided to buy a Falcon, that's great,,,

so have you flown the Falcon ? if not your going to love it..

Jim
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
01-14-2006 01:05 PM  13 years ago
SteveH

rrProfessor

Texas

MyPosts All Forum Topic
eagleboard,

The bolt that I start out with is long...probably 30 mm long. It needs to be long enough for the unthreaded part to go thru both juntions of the shaft and auto clutch sleeve.

Jim and Al,

It is my opinion that the bolt does not break from being tight...it breaks from the constant torque and change in torque applied to the system by a single cylinder two cycle engine causing a shearing effect, and the bolt without threads in the area of the junction is much stronger. Esentially it is as strong as the same size pin that's used in the Predator for the same purpose.

If the bolt was breaking because it was too tight, it would break relatively soon in life, but takes a good while, like a year or so of flying. It's just like the bolt that is supplied in the kit to hold the rotor head on, the Jesus bolt. Take a look at that specific bolt and you will see it is a hardened bolt with threads only at the end, and not at the junction of the head and the shaft.

It's simply much stronger for shear loads.
The government cannot give you anything without first taking it from someone else.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
01-14-2006 03:39 PM  13 years ago
Butch

rrVeteran

New York

MyPosts All Forum Topic
"Shear"
Critical area involving pleanty of "Shear" type force. As Steve mentioned, select a hardened bolt that has a long enough un-threaded portion (shoulder)which extends through the intersecting area of the mainshaft and gear/hub.

When youre done tightening an assembly, there should be at least THREE FULL THREADS, visible beyond the fastener.

Technically, Fiber Lock-Nuts are used ONCE, then replaced. Check often if you re-use.
The Whirlybug Bit Me!
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
01-16-2006 06:02 PM  13 years ago
jackheli

rrProfessor

Vancouver - Canada

MyPosts All Forum Topic
Sometimes the unthreaded portion of the longer cut bolt is a little too long and will wiggle in the slot. Just add a couple of washers on each side of the hub to tighten the assembly. This will also ensure that only the solid part of the bolt touches the hub.It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 514 views POST REPLY
Home✈️Aircraft🚁HelicopterCentury Radikal G20-30 N640 Hawk Predator › inaccuracy in falcon instructions
 Print TOPIC  Make Suggestion 

 5  Topic Subscribe

Monday, September 16 - 1:04 am - Copyright © 2000-2019 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online