Hanger 9 Aresti

[Jaybird]

I have an OS 46 FX inverted in this aircraft and I'm having trouble
getting the engine which had been running very reliably right side
up to idle and transition upside down. I have lowered the tank
as much as the setup allows but there is still too much fuel at
idle. I have even closed down the mixture screw. My next step
seems to be using a "Perry" oscillating fuel pump. Has anyone
else had and solved this similar problem with an inverted engine?:mad:

[Dima]

try to remove the cone baffle from the silencer. this should reduce the air pressure in fuel tank at idle and help you with your problem. although the engine will become a bit more noisy

[Jaybird]

I installed the Perry pump this weekend and after a few mixture
adjustments the engine was running like it's old self again. This
.46 FX has a lot of power and once I get used to the plane it
should be a lot of fun.:)

[imsofaman]

Glad it worked but I thought Dima had the right idea. Good luck!

[Jaybird]

I didn't get his reply untill today (Monday)so I didn't know to try it
untill I had already installed and tested the pump on Saturday.

Thanks for the ideas though. It's great having a resource like
this to use for help.

[Dima]

im happy u fixed ur problem. i got 46 FX myself and its a pure joy to use this engine. easy start and plenty of power just what i need for a weekly fun =)

[jamarha]

Hi,
I also bought Aresti 40 and i do not have problem with my engine.My engine is MVVS O.49.Imade new hole under engine mount so the center of fuel tank is slightly below center of carburator.I patched original hole because I don't want any fuel going into fuselage.Center of the tank is now about 1/4 inch below center of carb.I didn't have any problem with setting of idle.
However I have another problem .It's flutter of the elevator.watch out.I already crashed twice because of this.Do you have same problem also?

[Jaybird]

Jamarha,

I have noticed flutter and I would recommend some sort of wire
bracing like they do on larger model models between the stab
and the vertical fin and lower fuse. I'm still experiencing engine
problems in flight. It runs great on the ground and held in a
nose up position. Once in the air and running at 1/2 to 3/4
throttle the engine quits. My last three flights were all dead
stick landings. This plane really glides far and fast and hit
the tall grass pretty hard the last time and did some damage.
There was plenty of fuel and my other plane was running fine
so I'm not sure where to look for a solution. I'm wondering if the
Perry pump is causing or experiencing something in flight that
shuts down the fuel flow. I may try lowering the tank again
or trying a different shaped one. :(

[jamarha]

Hi Jaybird,
sorry about your trouble with engine.Do you thik that you can send my some drawing of that bracing you talk about. I'm not originaly from this country and sometime it's hard for my to imagine things just by description.I send my plane back to HORIZON for evaluation and they said that they will send my new parts.You should write them too about flutter.Because there is another guy that I'm in contact with and he has same problem .He said that it was bad servo.He replace it , haven't had problem since.He run SAITO 72 in it.I think I will reinforce stabilizer before I glu it in. What you think?I also want put stronger elevator servo with metal gear in it.
Jeremy

[Jaybird]

Jamarha,

It may be the pushrod linkage itself that is flexing and causing
some of the flutter. The bracing I'm talking about is available at
most hobby shops (a good one is a great source of help and
information) and is made up of cable or metal rods that form a
triangle between the horizontal and vertical surfaces. A good
servo is also important but I'm not sure a metal gear one will
make much difference in this case. If you want to spend the
money it's your choice but I think the pushrods need as much
guiding as you can. The thing to determine is whether the
stabalizer (non-moving surface) is fluttering (which the bracing
would help) or the elevator surfaces (moving parts) are fluttering
(which the bracing won't help but the pushrod guiding will)
Do you have a club or other builders nearby that can give some
"hands-on" help to you?

Good luck!

Jaybird:)

[imsofaman]

I do not have an Aresti but if you click on my link, my Speedy Bee also had flutter in it. I had to change one of my servos. I ended up changing all of them to metal gear which made me feel better. It fluttered as I was comming out of a dive. Actually...I think I stripped a gear just before the dive because as I was diving, the elevator would not work, I had to jog it up and down then I lost control and actually climbed a tree with my new plane! So......it is better to be safe than sorry. My plane is back together except I have to cover half of the wing.
Good luck with your plane. I would check your plug after the dead stick....look to see if it is dry or wet. I think maybe you are too lean. My LA 25 was doing the same thing so I richened it up and have had no problem. Did you leave the cone baffle in the muffler? If not you may not have enough back preasure.

http://www.radiocontrolzone.com/forums/showthread.php?s=&threadid=90505


Dave

[Jaybird]

The muffler is complete and I do think that a vacuum is happening
with the pump and fuel flow quits. I do run it rich. I think I'll take
the pump out and try lowering the tank while I'm repairing the
trailing edge wing mount. The mount broke lose but the nylon
bolt did not. I haven't had mine up to full speed yet so I'm not
sure what control surface problems will arise. I don't consider
this plane to be a high level aerobatic plane so I plan to take
it easy on it...if I can keep it running!

[imsofaman]

Jaybird,
Because of your reply about the elevator linkage flexing, I figured out what was happening to my Speedy Bee! My linkage was flexing so much, that I was diving......tried to pull up and nothing was happening. I slowed the motor down and the plane shot straight up ( into the trunk and branches of an elm tree). After reading your reply about the flexing linkage, it all made sence. Thanks! She is ready to fly again!

[Jaybird]

imsofaman,

Another method that a friend of mine uses is to run the pushrods so
that "up" elevator is a pull instead of a push which also eliminates
the flexing problem as most pushrods will flex when "pushed" if
they aren't supported somehow. The control horns have to be repositioned
too to allow this set up so looks can come into play.

Happy Flying!

[imsofaman]

Great idea......thanks for the info!!!!!

[jamarha]

Jaybird,
I just got of the phone with Horizon people.they told me that flutter was caused by bad balsa selection on hor. stabilizer.They going to send me new plane minus wing. I still thinking about reinforcing it anyway. I was looking for that bracing ,but all I could find was wire type.I was more thinking about something like pice of aluminum something like landing gear only smaller.In my hobbyshop they carry only wire type and they don't know who make the one I want.I tried to search internet, but cannot find anything so far.Maybe you or somebody else know? I will try to keep in touch when my plane arrive.Until than good bye and thankls for your help
Jeremy

[jamarha]

Hi,
I wasn't here for long time.But I got my plane flying.Since they send me new plane I didn't have any problems with it.They propably had more complains like mine because they reinforce inner structure of hor. stabilizer.Anyway it flyes great ,I can recomend this plane to anyone.It's fast plane ,we clock it going 85 mph with radar gun.
Jeremy

[Edge540]

If you find your 46FX starts to lose power an compression, send it back and make sure they fix it for free.


OS do not use genuine chrome on the pistons and liners in the 46FX, and as a result, it all flakes off and can be found in the exhaust oil. I believe they use nichrome or something with a more weird name!


As a result of this OS engines are now very very poorly rated in the UK where i'm from!


Just to let you know, as you'd be getting ripped off if you had to pay. A friend got treated really badly when the UK dealer wouldnt fix his FOC, so he complained to the Japanese office who sent him a whole new engine FOC!

It's a pure reliable engine for a long time, until the above happens. We actually managed to prevent this by using synthetic oil.

[Compflight]

Jaybird,
I just got of the phone with Horizon people.they told me that flutter was caused by bad balsa selection on hor. stabilizer.They going to send me new plane minus wing. I still thinking about reinforcing it anyway. I was looking for that bracing ,but all I could find was wire type.I was more thinking about something like pice of aluminum something like landing gear only smaller.In my hobbyshop they carry only wire type and they don't know who make the one I want.I tried to search internet, but cannot find anything so far.Maybe you or somebody else know? I will try to keep in touch when my plane arrive.Until than good bye and thankls for your help
Jeremy

Could it be the flutter is caused also but not exclusivley by the material of the pushrods themselves. They do seem rather soft.
This is my first build of this aircraft and have stripped the covering and filleted the joints of the tailplane.
One thing that everyone has missed is that flutter can be caused by tip vortices, particuarly likeley when they happen at high speed. I therefor have changed the design so the design is now inset, as per the ailerons and the rudder. trouble is if I get no flutter I will not know actulally what stopped it.
Oh yes, and hopefull it is not overpowered with as SC52.
Certainly the choice of balsa selection was not an issue. It looked like what I would have chosen if I had scratch built it.

[tandemairbike]

Hi Guys.
Back in the seventies a flying buddy of mine had an "Eyeball" pattern ship with a hot HP .61 that was radared at 112 mph. He had all kinds of aileron and elevator flutter problems. He tried everything imagineable and finally solved the problem by sealing the gap in the control surfaces with Monokote.
Might be worth a try.
good luck,
Terry

[Compflight]

Yet another idea.
One thing that has jumped up and bit me and I am suprised no one else has noticed is that the pushrods supplied in the kit are 1.8mm. Hardly suitable if they were short but the design uses quite large lengths of unsupported pushrods on the elevators. I guess the rudder would get away with it but the elevators. I just dont thik so.
I am changing these all to standard 2mm pushrods. The dual elevators uses one dowl as the main rod which I hope to be able to change to two dowels and link them together near to the servo. A method used in many planes. All depends on the room.
My main thoughts now go with the long lengths of unsupported 1.8mm pushrod at the elevator ends.
I may seal the gap as well for a real belt and braces job.
In nearly all cases the flutter ocured with over powered aircraft. I hope the SC53 should not be in that catagory though. Although I do want pretty good verticals!