DISCUS54

My Feedback: (211)

Hi guys...I have a retro project underway...a Summit 120 that I am redoing. I thought a YS140 Sport would work well, but now that the YS115FZS is available perhaps that would be better alternative. I have little experience with YS engines and none with the Summit...does anyone have experience with the Summit 120 and an idea of what would be optimal? Thanks.

J Lachowski

My Feedback: (46)

had one years ago. YS140FZ was in it.

DISCUS54

My Feedback: (211)

Joe,
I think the FZ and Sport are basically the same for power....how was the vertical performance?

MTK

You might want to weigh the plane. If it weighs about 8 1/2 lbs, the 140 will give good to excellent vertical especially on 30% nitro. If it weighs 10 lbs, the 140 will still fly it okay but vertical would be fair to poor.

I had a Summit III about 15 years ago with a piped YS61. At 7 lbs 4, the 61 did a marvelous job with it. The Summit 120 is a larger, heavier plane than the Summit I had. I think the 115 4S will not be satisfactory, but depends on your expectations for performance

DISCUS54

My Feedback: (211)

Thanks MTK....I was wondering if the 115 would be enough....probably just go with the 140 Sport.

Jon Wold

The weight will decide that for you. If you can get away with the lighter engine (115) you should go that way. But if you're gonna have to add lead to the nose, put the 140 FZ in there.

apereira

Hi DISCUS54,

The Summit used to be flown in competition with the YS120AC, I think the new 115 should have about the same power.

The thing in my opinion is, if the 115 proves not to be enough(I think ir should be fine if the airplane is light), can you install the 140 later without mayor mods?

Regards

Alejandro P.

jgg215

The 120AC weighed 990 grams and the old 120 which predated the AC weighed 880 grams . These are the engines that would have been used originally.
The currently available140FZ(Sport) is listed at 890 grams and the 140DZ is listed at 920. You should be able to find a used 140DZ refurbished for around $300.
The 115 weighs 735 grams and you will probably have tailheavy issues to contend with. IF you can keep the airframe very light, particularly in the
tail, you could end up with a very good flying model using a 115. The 115 should be more than adequate power compared to the original engines used. However, it sounds as if you might be reconditioning an existing model which is unlikely to be very light 20 years later.
If so you can use the weights listed above to trial balance the model with different engines. Don't forget to add something for an exhaust system.

John

DISCUS54

My Feedback: (211)

Lighter is always better, that's what got my attention about the 115. I would rather not rebuild the tailfeathers to balance it up. I think the 140 is going to be a better fit (not looking to compete with it) with retracts, lightly glassed wings, ect.....not optimal at all on the weight....but I think with a new coat of paint the cool factor will be very high. Thanks for all the input.

David Bathe

I'd vote for the 1.40FZ/sports. 

DISCUS54

My Feedback: (211)

Thanks guys for all the info....I went ahead and bought a 140 Sport. I'm looking forward to bolting her in!

MTK

It should a good combo. I think you said that you are re-finishing the plane. Needless to say, weigh everything at every step to minimize it. Re-finishing can add real lbs to your crate.

The 140 FZ/sport is not as strong as the DZ but it has better field manners.