RunRyder RC
 5  Topic Subscribe
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 1231 views POST REPLY
Scorpion Power Scorpion Power
HelicopterMain Discussion › Strange crash
12-02-2007 08:06 PM  9 years agoPost 1
Jonty

rrVeteran

Wellywood

My Posts: All  Forum  Topic

Guys, thought I would see if anyone could shed any light on my smack yesterday. I am running an R50, GV-1 and OS 50 hyper and coming off a tick tock the engine died then suddenly revved up an enormous amount while the headspeed literally died. She came in hard. The over reving blew a hole in the piston, but I am not sure this was the orginal cause. My first suspect is that the clutch failed. However the liner didn't look to bad although it was a bit shiny. The second question is why didn't the GV-1 prevent the huge increase in revs if the clutch died?

All a bit of a mistery, but luckily I came away with only a broken boom and a broken piston. I'll replace the GV-1 sensor and have got a Quick UK clutch coming

Cheers

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:11 PM  9 years agoPost 2
MMike

rrElite Veteran

Holland,Mi-USA

My Posts: All  Forum  Topic

Jonty

This might be a stupid question:

Were you in idle up?

MMike

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-02-2007 08:16 PM  9 years agoPost 3
rcfreak7

rrApprentice

southern california

My Posts: All  Forum  Topic

the engine might have stalled and restarted spinning in the opposite direction. The one way would have not engaged and the engine would have almost no load explaning the high rpms. there was a thread on this a while ago but I couldnt find it.

i am my own dog

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:20 PM  9 years agoPost 4
Raptor Pilot

rrVeteran

Northern Ireland U.K

My Posts: All  Forum  Topic

strange crash

Im no expert but..... the hole in piston is a sign a hyper was running lean and melted a hole. The engine dying down and reving up again is a sign of running lean too. However, i cant offer any explanation of the head speed dying and the revs going up unless the clutch broke both shoes. My 50 SE broke one shoe and i didnt notice untill i was shutting it down and heard a rattle when it was idleing. If the guvoner pick up sensor is on the maingear and it starts to slow because of mechanical failure somewhere, naturaly the revs are going to go through the roof. Hope this helps as i dont like strange happenings before a crash either.

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:23 PM  9 years agoPost 5
Raptor Pilot

rrVeteran

Northern Ireland U.K

My Posts: All  Forum  Topic

rcfreak7 is right as this can happen but it mostly occurs when you are starting the engine and it kicks back and runs backwards.

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:32 PM  9 years agoPost 6
Jonty

rrVeteran

Wellywood

My Posts: All  Forum  Topic

RCfreak - good thinking. Yes that could be an explanation as the clutch and clutch liner didn't seem in terrible shape. The motor did die and speed back up so that could explain it. If you could find that thread I would be interssted to read it. I suspect it was too lean as I have just changed needles and i was trying to retune. I brough it in first and it was to hot so I opened it up a lot but it can't have been enough. Yes, I was in idle up

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:46 PM  9 years agoPost 7
rcfreak7

rrApprentice

southern california

My Posts: All  Forum  Topic

http://www.runryder.com/helicopter/...reverse+running this is a thread about reverse running. its not the one i was thinking of but it nmight help if this is the problem. MMike why did you want to know if he was in idle up? just curious

i am my own dog

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:51 PM  9 years agoPost 8
Jonty

rrVeteran

Wellywood

My Posts: All  Forum  Topic

Cheers - I would be very interrsted to know if an engine which is too lean has ever reversed on someone in mid flight. The engine died then kicked back into life. It would explain a lot. I hate crashes where I can't find the cause

PM  EMAIL  GALLERY  Attn:RR  Quote
12-02-2007 08:54 PM  9 years agoPost 9
MMike

rrElite Veteran

Holland,Mi-USA

My Posts: All  Forum  Topic

RC7

Believe it or not.

I have replaced about 6 clutches in a Kyosho Nexus 30.

If you don't have the rpm'S in a tic toc, the clutch will slip as the shoes are momentarily unseated IF you're not in idle up.

I presume Jonty was in idle up as no one picked up on my "stupid question"

MMike

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-02-2007 08:57 PM  9 years agoPost 10
rcfreak7

rrApprentice

southern california

My Posts: All  Forum  Topic

okay, that makes sense

i am my own dog

PM  EMAIL  GALLERY  Attn:RR  Quote
12-03-2007 09:27 AM  9 years agoPost 11
subarus

rrNovice

South East Asia

My Posts: All  Forum  Topic

sounds like the engine was not getting fuel.

were there fuel in the intake line after crash? note that I didn't ask if there were fuel in the tank.

PM  EMAIL  Attn:RR  Quote
12-03-2007 10:06 AM  9 years agoPost 12
WJackson

rrElite Veteran

Smyrna, Delaware

My Posts: All  Forum  Topic

Slipping one-way will cause what you described. If throttle hold isnt hit soon it will also make the gov go to high throttle and fry your motor too.

RIP Roman
Bill Jackson
AlignUSA

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-03-2007 11:09 AM  9 years agoPost 13
cupra

rrApprentice

leicester uk

My Posts: All  Forum  Topic

why did the governor / limiter hold it back from reving ?

could the magnet have come out ?

PM  EMAIL  Attn:RR  Quote
12-03-2007 11:19 AM  9 years agoPost 14
daren

rrVeteran

Hampshire Sponsored by Quick UK

My Posts: All  Forum  Topic

I had a ys91st in a fury tempest fai reverse direction while doing a stall turn, hit hold straight away and auto'd down.

Daren
Using the ground to reverse engineer

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-03-2007 12:47 PM  9 years agoPost 15
garry keogh

rrApprentice

Wicklow, Ireland

My Posts: All  Forum  Topic

Engine went backwards - no question

Jonty

I had exactly the same thing happen to me earlier this year and it took some explaining before everybody believed me.
It happened me in the middle of my set manouvres in the Heli Challeng Trophy event in Ireland so I had plenty of witnesses. During a pretty benign half cuban 8, I pulled over the top and before I rolled right way up, the engine cut almost completely, then burst back into life but at massive rpm. I was still inverted, took a moment to spot that the head speed was falling off, have never tried an inverted auto... you can guess the rest.
The heli came down very hard straight onto the main shaft/collective tray. Pretty much the entire Quick UK metal head written off along with several servo gear sets I was using a TJ Pro governor and it seemed as if it did nothing to slow the motor. It is important to think about this too. The motor going backwards has ZERO load on it. Even with the throttle almost closed, it will speed like hell. I only have one question about the TJ Pro. I wonder in an overspeed condition, will the governor keep closing the throttle to a limit to reduce rpm (like a gyro does in Heading Lock mode to stop piro)or does it just offset the throttle in a negative direction by a default offset from the position defined by the curve underneath it, waiting to see a fall in rpm? Not the real reason I guess for the engine screaming, that was the zero load I suppose

I took the heli apart on the spot and it was pretty obvious that it had kicked backwards. While the motor ran for the full 3-5 second free fall and for a couple of seconds after it hit the deck, there was not even 1 speck of clutch dust. To really confirm what had happened, I noticed that the start shaft had tightened up. When I looked closer, I could see that the pinion had un-screwed a couple of turns from the clutch bell pulling apart on the start shaft bearings. This can only happen if the motor is going backwards. QED

Some of the more experienced hyper users had a look and reconed that I was quite rich on both needles. This in itself makes sense as a rich or flooded motor will kick and run backwards when you are starting up. The reason for the motor sagging is totally different. I had seen it before at the bottom of tail slides but never at the top of a +G manouvre? I changed the tank and plumbing and the motor still did the sagging thing. Thankfully with the needles leaned out a little, the running backwards has not happened since

Hope that this helps

Garry

PM  EMAIL  GALLERY  Attn:RR  Quote
12-03-2007 07:08 PM  9 years agoPost 16
Jonty

rrVeteran

Wellywood

My Posts: All  Forum  Topic

Cheers Gary, all sounding very familiar except I probabaly would have been too lean as opposed to rich. My one way seems ok but i may change it out in case.

Thanks all - it really has turned out to be a strange one

PM  EMAIL  GALLERY  Attn:RR  Quote
12-03-2007 07:44 PM  9 years agoPost 17
MattJen

rrElite Veteran

UK

My Posts: All  Forum  Topic

[quote]I had a ys91st in a fury tempest fai reverse direction while doing a stall turn, hit hold straight away and auto'd down.

Daren

i read you post with interest, as i had aproblem on my YS91st, in my venture, i was doing a top hat for the B test, so i was in hovering speed, the engine then suddleny roared as if the throttle push road came off, i had no control, in the end i crashed the machine as it became a danger to the sheep..

In hindsight i would have done an Auto as i have a few fuel tubes come off and had to auto down whilst inverted, so Auto's are not a problem,

I am curiose as i only thought the engine could go into reverse on start up, NOT whilst flying.

Matt

All The Best

PM  EMAIL  GALLERY  Attn:RR  Quote
12-03-2007 08:32 PM  9 years agoPost 18
lfalsetto

rrKey Veteran

COLORADO

My Posts: All  Forum  Topic

Did you have a header tank on it. IF so the bubble in the header tank could have been to large when you went tail down the tank went lean and leaned it out and the engine caughed. OR you could have a hole in the clunk line causing a lean situation.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
12-04-2007 12:35 AM  9 years agoPost 19
A. Gordon

rrApprentice

Farnham,Va.-USA

My Posts: All  Forum  Topic

OK, I'll ask the question again. Why didn't the gov. cut the rpm's back? I run a rev max on both my heli's and it is supposed to limit the engine rpm. Did any of you have a magnet fly out? That as far as I uderstand it, should be the only reason for the increase in rpm's. Am I wrong in thinking this?

All for the spectators!!

PM  EMAIL  Attn:RR  Quote
12-04-2007 12:41 AM  9 years agoPost 20
MattJen

rrElite Veteran

UK

My Posts: All  Forum  Topic

A.Gordon
Why didn't the gov. cut the rpm's back? I run a rev max on both my heli's and it is supposed to limit the engine rpm. Did any of you have a magnet fly out?

i do not know, but what i am sure, of both magnets were fine, and still in place.

I did have a loose clutch bell shaft which had dropped and was rattling around in the bearing on my Venture, someone said this would be enough to cause interference that could mess up the GV..

I have also heard of other Venture flyers who have had a like a partial glitch which was enough to knowck out a couple of channels but not enough to send the machine into failsafe.

I never got to the bottom of it..

Matt

All The Best

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 1231 views POST REPLY
Scorpion Power Scorpion Power
HelicopterMain Discussion › Strange crash
 Print TOPIC  Make Suggestion 

 5  Topic Subscribe

Monday, October 23 - 2:35 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online