3W Engines and fuel tank setup

[Ashkanani]

Hi All...
Am having a problem with my 3W YAK54_Airunner scheme..that I did adjust the engine for first fly... On full throttle the engine is OK... but if am entering any manuvers you feel like loosing power at the beginning.. like going and coming...and especially on inverted and knife edge flights..
I talked to Gerhard at Aircraft Internationaland told me that I need to redirect the air away from the carb.... the problem that I did open th ewhole thing in the cowling as that attache pic.... and don'tknow what to do....

Please advise.

Thanks
Abraham

[Kiwi]

Abraham,

Do you have the 90 degree air intake elbow on this engine or is just the carburettor intake directly in the air path.

This picture has the elbow. Is this what you have?

Kiwi

[Bunky F. Knuckle]

Sounds like you might be a tad rich on the bottom end?? If I get a little hesitation on my 3W's, i lean the bottom out, just a tad,and the hesitation pretty much goes away!!

How does your engine transisition from idle to wide open??? Does it hesitate(cough cough), or does it sag(bluh)???

Once you return to upright, the problem relieves itself, correct??

Looks like you are running either a QS or CS 150???

Let us know if we can help in any other ways!!

Chris~

[Ashkanani]

My Engine is QS and yes the snorkel is installed.....on the ground the engine is perfect at idel and top end.... but the engine hickes little bit only at the entry o fa knife edge or rolling then continue fine....
Now what am trying to do is to redirect the air away from the carb.... and what I think which is toooo late ....that grill shouldn't be open like what I did...it should be more closed and openned in a way that leed the air away from the carb...

Abraham

[Bushman]

Hi Abraham

I had exactly the same problem as you. It drove me nuts. Played with the airflow and everything else you could think about.
Quique told me to close the low needle a bit.
I started closing the low needle a bit at a time untill the problem disapeared.
The engine never dropped rpm again and even the small flat spot at low rpm when you torque roll went away. The cowl is fine mine is opened the same way and I have not had any problems even flying in very hot days with log Torque rolls.
Unfortunately the plane landed on the wrong side two weeks ago so now it will take a bout two weeks to get the other one flying.
I saw you have the 3W votec in one of your pictures. Busy finishing two pieces how does it compare to the YAk?
Alex

[Ashkanani]

Hi Alex...
Sorry for the damages.....Well I'll try to close the low little bit and check it out... I just got the 3W air filter hoping that it would solve the problem.. at least to make the air stable at the snorkel.....
As for theVOTEC.... it's for my friend and am putting it together for him... and till now we didn't fly it... haveing few problem to determine the right CG point..

Abraham

[Bushman]

Hi Abraham

I will start my two votec's in a few weeks I am going to the usa for two weeks. Did you by any chance go to the 3W show last year??

Alex

[Bunky F. Knuckle]

Honestly, I would not worry too much about the air filter. I do not think that you need it. No need to block off the lower part of your cowl either. Since you have the "snorkel", you can run the low end a tad richer, than what you could without the snorkel. Hope I got that right! But anyways, start cranking(not physically) down on that low speed needle, and see what happens. Tweak it a tad here, a tad there, and soon enough, you'll find the SWEET SPOT!!!

Keep us informed!

Chris~

[Ashkanani]

Hi Bushman: actually NO.. I was going but last moment cancelation....

Hi chrisfry..
I didn't install the Air filter... I did close some of the area in the cowling.. and the plane now running great.... I took it out last Saturday when we had the pilots from the FLYING BULL's in Q8... after thier show we gave them a small fine show....