OS70FL set/tune up inverted.

OS70FL set/tune up inverted.
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OS70FL set/tune up inverted. - 5/20/2008 12:33:58 PM

PSJDBF

Posts: 63
Joined: 1/24/2008
From: PannawonicaWestern Australia, AUSTRALIA
Status: offline

Hi all.
A friend I fly with gave me an OS70FL that he had given up on as he could'nt get it to run.
He had sent it back to the store where he purchased it they said they had completed the break in and that it ran fine but he still had no joy with it.
I had just got a great deal on ebay for a super chipmunk kit 40-46 2c , 52-70 4c so he offered me this engine to see if I could get it running (I have mostly 4 cycles ).
I have mounted it inverted...I have read all the negative posts-comments about this engine and the few positives.
Decided to go ahead and try it anyway....certainly not as user friendly as my other 4c engines.
None the less i have it running and have put 2-3L's of fuel through it whilst trying to tune it.
where I am now is it idles quite nicely 3-4 minutes and from idle to peak RPM is responsive.. there is a slight lag but you would have to be on the stick to notice I think and it does'nt miss or cough.
Have adjusted the air bleed screw untill throttle response is as good as I can get it and when the nose is raised there is a slight rise in rpm and when lowered a slight drop in rpm but it does not cut out and seems to be happy in this spot.
It took alot of small adjustments to get it at this happy medium and now it seems to run steadily in all positions with the plane in all attitudes.
I am by no means an expert in tuning glow engines and this one has me settling on a happy medium where it seems to be leaning off a little with the raised nose but does'nt seem to mind it ? and seems to be responsive and reliable.
I have added a link to a utube vid of my tune up so you can see for yourselves and hear what I have been descibing I would be interested in your experienced comments suggestions/advice BUT PLEASE no cheap os crap bashing !! just some constructive comments Good or Bad !.
All the best Steffan.

http://www.youtube.com/watch?v=ixSMjPj8JjY

< Message edited by PSJDBF -- 5/20/2008 2:04:17 PM >

Post #: 1

RE: OS70FL set/tune up inverted. - 5/20/2008 11:41:33 PM

The Ghost

Posts: 797
Joined: 3/18/2004
From: UlladullaNSW, AUSTRALIA
Status: offline

What people forget is thet these are ringed engines (people are used to grabbing a 2stroke ABC/ABN engine running once and then flying) and very few people remember what it was like running in these or old iron piston/cylinder. I have had several (Satio,OS,Magumn) 4strokers that required at least a 4 ltrs of fuel before they would hold a idle and transition to full without quiting. Sounds like you have just got the engine to that point. Good luck with it.

Cheers

< Message edited by The Ghost -- 5/20/2008 11:43:12 PM >

_____________________________

Remember, Always look after the ORGANIC part of the model

(in reply to PSJDBF)

Post #: 2

RE: OS70FL set/tune up inverted. - 5/21/2008 3:14:11 PM

PSJDBF

Posts: 63
Joined: 1/24/2008
From: PannawonicaWestern Australia, AUSTRALIA
Status: offline

Hey the Ghost hows things.
The 70 FL was their cheap/introduction 4 stroke and one of the reasons
it was bashed so much was because it is an ABC ringless piston design and
an up draft two needle carb and plenty of people it seems have had alot of
dramas running them.
the chipmunk requires abit of weight in the nose so I'm now going to mount
a pro glow glowplug driver unit and mount the battery behind the fire wall
just for a little added insurance ...If I need to add weight might as well make it usefull.
Cheers Steffan.

(in reply to The Ghost)

Post #: 3

RE: OS70FL set/tune up inverted. - 5/24/2008 4:53:53 AM

PSJDBF

Posts: 63
Joined: 1/24/2008
From: PannawonicaWestern Australia, AUSTRALIA
Status: offline

Hey guys a bit of an update.
1st flight today for the chipmunk !.
originally I had a master airscrew 13x6 prop & high idle was at 9.450rpm
but she was to much at idle (still wanted to roll ) and I felt that i would not get
her back down..so i changed it out for a 11.5x6 bolly reset the idle & glow driver
and tried that ...High idle was 11.000rpm and she sat nicely on the hard ground at idle.
Deep breath ...here we go she tracked nice and straight lifted off and dropped the right
wing but climbed out ok cut the throttle back to half as she was a rocket at full throttle
and spent the next minute or so madely trimming her....alot of down elevator and left input.
(at this time she was very high & doing big loops).
After the mad trimming she settled into a nice stable level flight I then cut the throttle back
to idle and checked the slow speed which i,m pleased to say was stable no wing drops and was quite
happy in a shallow turn with no throttle then cranked her up and tried some rolls and controlled
loops etc ...then decided not to push it on its first flight and brought her down into a landing circuit.had to
do two circuits to wash the speed off then dropped in over the trees on final just a touch hot
she flaired out perfect and touched down with little impact ( a small bounce ) and the left hand main wheel
colapsed !!.Turns out it seems to be a problem with the CMPro kit so maybe this is a CMPro or a copy.
So a bit of work to do to strengthen the landing gear blocks but all in all I,m impressed with the
flight characteristics of the super chipmunk (once trimmed ) and the OS 70 FL performed flawlessly
it is certainly more than enough up front for me I dont think I would want any more.
Some pics before the flight.
All the best Steffan.

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< Message edited by PSJDBF -- 5/24/2008 5:09:09 AM >

(in reply to PSJDBF)

Post #: 4

RE: OS70FL set/tune up inverted. - 5/24/2008 11:44:40 AM

da Rock

Posts: 6366
Joined: 10/11/2005
From: western, NC, USA
Status: offline

quote:

ORIGINAL: PSJDBF

Hey guys a bit of an update.
1st flight today for the chipmunk !.
originally I had a master airscrew 13x6 prop & high idle was at 9.450rpm
but she was to much at idle (still wanted to roll ) and I felt that i would not get
her back down..so i changed it out for a 11.5x6 bolly reset the idle & glow driver
and tried that ...High idle was 11.000rpm and she sat nicely on the hard ground at idle.
Deep breath ...here we go she tracked nice and straight lifted off and dropped the right
wing but climbed out ok cut the throttle back to half as she was a rocket at full throttle
and spent the next minute or so madely trimming her....alot of down elevator and left input.
(at this time she was very high & doing big loops).
After the mad trimming she settled into a nice stable level flight I then cut the throttle back
to idle and checked the slow speed which i,m pleased to say was stable no wing drops and was quite
happy in a shallow turn with no throttle then cranked her up and tried some rolls and controlled
loops etc ...then decided not to push it on its first flight and brought her down into a landing circuit.had to
do two circuits to wash the speed off then dropped in over the trees on final just a touch hot
she flaired out perfect and touched down with little impact ( a small bounce ) and the left hand main wheel
colapsed !!.Turns out it seems to be a problem with the CMPro kit so maybe this is a CMPro or a copy.
So a bit of work to do to strengthen the landing gear blocks but all in all I,m impressed with the
flight characteristics of the super chipmunk (once trimmed ) and the OS 70 FL performed flawlessly
it is certainly more than enough up front for me I dont think I would want any more.
Some pics before the flight.
All the best Steffan.

G'day mate.......

I'm not familiar with the idea of a "high idle". But the rpms you've quoted sounds like Wide Open Throttle for some engines that size and power. Idle on the ground ought to be less than 2,000 rpm. And if your radio settings and pushrod rigging won't give that, it's no wonder it takes a couple of circuits to slow down. The idle setting is what really helps slow a model in the landing pattern. Go directly to idle and the prop acts as a brake. Watch the airspeed and when the airplane is approaching the speed you want for landing, click the throttle back up 2 or 3 clicks from idle. And you'll have the airspeed you want for landing. A couple of touch and goes and you'll know how many clicks holds the appropriate speed.

Sounds like you had an eventful maiden. So where are the surfaces now that it's been flown? Elevator straight back? Ailerons line up with each other?

Isn't it kewl when the before the flight pictures show what the airplane looked like after the first flight?

< Message edited by da Rock -- 5/24/2008 11:46:09 AM >

(in reply to PSJDBF)

Post #: 5

RE: OS70FL set/tune up inverted. - 5/24/2008 12:13:04 PM

PSJDBF

Posts: 63
Joined: 1/24/2008
From: PannawonicaWestern Australia, AUSTRALIA
Status: offline

Hey da rock hows things ?.
The idle was a little over 2000 rpm but was not enough with the 11.5x6 to
roll off on the hard ground we fly from.
High idle is a term we use in my profession for wide open throttle or max rpm.
The reason I had to do two circuits was because I was up that high she was picking up a
bit of speed in the descent ..probably could have explained myself a bit better it is certainly
a relief when you unload it at home after the first flight and its still relatively in one piece
( it keeps mum happy as well ).

Cheers Steffan.

(in reply to da Rock)

Post #: 6

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