New 3W Yak 37.5% - engine problem ?!

[tamir3DCrazy]

Hi Guys!
I had a new 3W Yak 37.5% and i wonder which engine is the best for this
beast .... The 3W 157 comp TS or the 170 comp TS ?!
If u have another suggestion it will be great
( i know that the new DA 170 is good option but Personally I like 3W more )


Thank you very much ( and sorry about my bed english )

regards
Tamir.

[Flyinhigh]

The 3W CS 157 and CS 170 both weigh the same and fill the same space, but the 170 is alot more powerful - if those are your two choices, ask your wallet The plane is a great match for the 170. Canisters are a little easier to pair up and tune than pipes, but straight exhaust is easiest (and loudest) of the three.

(I can't help but to add that the DA 170 is about a full pound lighter)

[TheTank]

I have seen this airplane with both 157s and 170s in them, and it performs great with either one.

[Vic3D]

	Quote: Originally Posted by Flyinhigh
	(I can't help but to add that the DA 170 is about a full pound lighter)

Good for the DA-170

Tamir, both motors will perform nice in this plane. Watch videos of QQ flying this plane back in 2002-2005 on a 3W-150 with canisters and you will see that the power is insane even on the 150. 157 will be even better, and the 170, well, you get the idea.

Get the one you can afford. If you don't mind spending a few more bucks, 3W-170CS would be BEAST.

[ljaganna]

Hello Gents,

I am getting ready to mount a DA170 to my new 3wYak(37.5%) airframe. The DA170 is lighter than the 3W150/170. So, is there somebody out there who has mounted a DA150 to this 3wYAK airframe? I need to know if I should add any aluminum spacers or perhaps 1/4 or 1/2 inch of ply to push the engine forward so as to balance it right.

Also, for folks who have the 3w157/170s mounted in the same airframe...did you push the engine forward for CG purposes or mount it straight to the motor dome? If you mounted straight to motor dome, how much does the spinner stick out in front of the cowl?

Thanks for your help.

LJ

[kim3D]

personally i would put the DA 170 as well
just becaue i saw one with 3W 170 with cans and it ended up heavy like 45 pound
and the DA runs better

[Shoe]

We have the 3W 37 1/2% Yak with a DA-150 inside. No problems pulling it around for IMAC or 3D. We did use 1/2" spacers to move it forward though, as it is not as heavy as the 3W engines.

[ljaganna]

Hello Scott's Dad,

Thanks a lot for the reply. What kind of mufflers did you use for the DA150? Pipes or cans?
If you balanced with 1/2 inch spacers, then if I know the type of mufs you used, I can see if the combo I am plannning to use with the DA170 is lighter or heavier in weight that what you have used.
I am using an SWB servo tray with 3 8711s, and I have 1 8711 per elevator.
What servos did you used for rudder-tray & elevator?

How far is your spinner in front of the cowl?

Thanks again,

LJ

[psk560]

I added 1/2 inch spacers on mine with ks 95 front exit pipes and 50 mm flex headers. My batts are under the cowl right above the motor dome. My spinner backplate is about 2 inches from the front of the cowl.

Craig

[Shoe]

We have the MTW front exit cannisters with 25mm flex drop headers. Batteries are under the cowl on the sloping part of the fuse, just aft of the motor dome. I think the spinner backplate is where it is recommended, about 3/4" in front of the cowl.
Shoe

[Showtime]

I Have a 3w 37.5 and it has a 170 on it. I also have one with a 157 and the 170 has a little more torque than the 157. As for weight my yak with the 170 is 39 pounds and I can prove it... It is the air runner scheme. Kim if you say a 3w yak at 45 pounds than something is wrong.. Like i said i have two of these planes both with 3w and both weigh under 40lb.

As for stands off on the motors. I have not pushed out the motor at all it is mounted straight up to the motor box.
If youy chouse the Da 170 with i am sure is a great motor but you will have to move all hour batts to the front if the da is truly 1lb lighter. ( stick with the 3w IMO)

[ljaganna]

Craig & Scotts Dad,

Are your Rx bats right on the fuse(behind the motor dome), or was that just the ignition battery that you placed there?

Thanks,

LJ

[Shoe]

LJ, we have our (2) receiver batteries mounted on the sloping portion of the fuse, just under the cowl. The ignition battery is mounted on the top of the motor dome.

[psk560]

LJ,

I have the same setup as Shoe. Three batts up front. Receivers on slope and ignition on top of motor box.

Craig

[Tired Old Man]

If I was the one making the choice and also lived in Israel I would probably go with either of the two 3w engines I wanted to afford. Less of a shipping cost and a much streamlined service process if ever needed.

If I was living in the U.S. I would likely still go for the 3w 157 over a DA 150, but if choosing between 170's I would take the lighter one.