BlockerAviation
Legendary member
You haven't experienced a backfire until you've handproped a Saito lol
Keep your hands away from props, kids
- Thread starter Quinnyperks
- Start date
Quinnyperks
Legendary member
Never done that one personally, but I’ve seen videos.
OliverW
Legendary member
You haven't experienced a backfire until your 176cc backfires cause you're trying to start it with a sheared hub key.. the backfire echoed so loud
BlockerAviation
Legendary member
You've got me beat
OliverW
Legendary member
It was loud enough it made birds come flying up from the stream out there 😆
Bricks
Legendary member
That is why on 4 strokes to double nut them locking the two nuts together better chance of not having the prop come off. Normally backfire comes from being a bit to lean only happens on the 4 strokes at least hard enough to throw the prop..
BlockerAviation
Legendary member
I've had backfires happen even when they're blubbery rich, I think it's just the nature of large boar glow fourstroks. But you're right, fourstroks have been the only ones to throw a nut in my experience, and my supertiger kicks pretty hard when it's angry. So far I've kept it fairly happy though!
tomlogan1
Elite member
How about having an engine cutoff switch on your controller? Don't turn the switch till your ready to fly.
Quinnyperks
Legendary member
That doesn’t affect it. When you are doing any type of ground run up or motor test, stay out of the prop arc!
FlyingWithRyan
Elite member
I just run a big spinner nut and torque it down super hard with a 7/8" wrench. Id estimate I torque it down to about 20 ft/lbs
That's the norm. The trainer switch is usually used for this, just pulls the carb shut to kill the engine. The engine cannot randomly start like an electric motor so you are 100% perfectly safe with the kill being a momentary switch like that.
My OS FS-70 Surpass is so bad about it that I actually take advantage of it. When I start that engine I prime it heavily, give it a few notches above idle, roll it past compression but not far enough to open the exhaust valve, then I turn the on-board glow driver on and flip it backwards with a chicken stick.
One flip start every single time, without fail. Busts right off. If I try to flip it the correct direction it will try its damndest to break my wrist but if I flip it backwards it just shrugs and flashes up.
None of my Saitos have ever done this but I also don't have any particularly large saitos. I have an FA-90TS but it's no torquier than my FA-40 or FA-45 MkII since it's basically two FA-45 cylinders on one crankshaft.
I have had my 46AX's spit a prop a couple times too. It's rarer with 2-cycles because they don't make as much torque but they can do it.
The worst backfire I ever had was an OS FS120 Surpass. I was chicken stick starting it and it kicked back so roughly it SHATTERED a pristine 14-6 wood prop.
PsyBorg
Wake up! Time to fly!
I watched a guy back in the late 70's break 2 fingers and tear ligaments in his hand using a hi torque electric starter on one of the new outboard boat motors that he was trying to do break in run ups on. He was busy yakkin about his new toy and I guess was only half heartedly holding the starter when it kicked back on him. Folded two fingers backwards as the starter flew out of his hand. Not sure why he had some sort of slotted style cup instead of one of the rubber style ones on most starters. I didn't know much about that stuff back then.
Aviator936
Member
I was once testing a motor on my homemade aeroplane with some spare foam board when the front crinkled and net and cut my leg really badly. That's what happens when your a beginner and you didn't do your homework.
Bigtex1984
New member
Just did the same
Aviator936
Member
Unlucky man. Fo to the hospital and get stitches. It hirts like hel, but it orevents so much scarring trust me
Mr Man
Mr SPEED!
True.
Piotrsko
Legendary member
I can show you ten foot of oak molding that my slow flier prop chewed a deep prop shaped gash every 2" spaced nice and pretty. Fwiw: I am suprised the prop went that far without breaking. Otoh, HOLY Poop, what a lot of carnage in a piece of oak. Piece of meat would have been ugly, can you say hamburger?
