RCU Forums - 3W 75i Question

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flyerdave

04-17-2011 03:51 AM

3W 75i Question

I have a 97" Hangar 9 Sukhoi and I am thinking of buying the 3W75i to pull it. Hangar 9 says a Zenoah G62 is at the bottom of the recommended power range. If a G62 will pull it, then shouldn't the 3W75 be a good power choice? Is the 3W a smooth running engine? sorry for all the questions, but I've never had a 3W.Thanks for your help.

STUKA BARRY

04-17-2011 07:27 AM

RE: 3W 75i Question

You wont get any 3D power out of the G-62. For the price of the 3W you could get the Zenoah GT-80 Twin and have a ball with the plane.

pauldo

04-17-2011 11:48 AM

RE: 3W 75i Question

The Zenoah 80 twin is not the ideal motor for this plane. It is very heavy, and down on power when compared to the 80cc singles. (It does make a great scale aircraft power plant, but not ideal for aerobatic aircraft where power to weight is a big consideration) Apart from the DA 85, the ZDZ 80 and MVVS / Evolution 80's are ideal choices for this plane. The early DA 85's had big vibration problems, but I understand that they have rectified this now. The ZDZ runs fairly smooth. The MVVS / Evolution, however, has 4 crank bearings. 1 rear, and 3 in the front. This is done to reduce crankshaft flex and deliver smooth operation (As smooth as possible for a big single)

rc bugman

04-17-2011 02:27 PM

RE: 3W 75i Question

Hi,

The 3W-75 is significantly more powerful than the G-62. Run 91 octane and 40-50:1 oil and have a lot of fun with it.

Elson

flyerdave

04-17-2011 05:16 PM

RE: 3W 75i Question

What prop should I use for this combo? (Hangar 9 sukhoi & 3W 75i) Thanks

rc bugman

04-18-2011 02:22 AM

RE: 3W 75i Question

I would start out with a 24 x 10 and play from there if the flight performance was not exactly what I wanted.

Elson

pe reivers

04-18-2011 02:41 PM

RE: 3W 75i Question

Quote:

ORIGINAL: pauldo

The Zenoah 80 twin is not the ideal motor for this plane. It is very heavy, and down on power when compared to the 80cc singles. (It does make a great scale aircraft power plant, but not ideal for aerobatic aircraft where power to weight is a big consideration) Apart from the DA 85, the ZDZ 80 and MVVS / Evolution 80's are ideal choices for this plane. The early DA 85's had big vibration problems, but I understand that they have rectified this now. The ZDZ runs fairly smooth. The MVVS / Evolution, however, has 4 crank bearings. 1 rear, and 3 in the front. This is done to reduce crankshaft flex and deliver smooth operation (As smooth as possible for a big single)

The MVVS 80 has no rear bearing. It does have three front bearings though. The front bearing in a 3D plane is extremely heavily loaded by alternating gyroscopic forces on the propeller.

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