Yamada vs Saito Four-stroke for Classic F3A pattern flying

[Richard Haynes 1]

I realise that this has been discussed before, but often rather far back in time. So... these days how would you good guys rate, for example, a Yamada FZ115s against a Saito FA125a. In the UK the Yamada is £395 and the Saito lowest price £270-£300.

My application issues are, as usual, size, weight, vibration, power output, and reliability. I don't mind the extra cost if it's worth it. The intention is to use it for a classic F3A aerobat weighing around 7lbs from the late 90s and the aircraft will need unlimited vertical and some degree of air braking on the way down, which is why I'm thinking weight might be an issue. Also, I do love the sound of a nice engine.

[Martin Harris - Moderator]

I suspect that you can discount weight as a factor in downline speeds unless the laws of physics have changed since I was at school...

Edited By Martin Harris on 24/10/2018 14:53:07

[Robert Welford]

I have used YS 63S, 110S and 160 DZ engines in recent years. The 115S is a development of the 110S.

The 110S is very powerful and I suspect more powerful than the Saito. I run 14 x 10 or 15x8 APC propellers on 110S, The 115S will be even more powerful, but is the same size and similar weight to the 110.

The downside of YS engines is:

• they are different to setup and maintain. Normal rules don't apply.
• limited support in the UK - only Probuild
• at least 20% nitro is required, so the fuel is expensive
• Hatori, who make the silencers and headers, seem to have ceased production

I use my 110s in an MK Skystar 90 and a Steve Dunning Rapture 110. Both have very impressive performance with unlimited vertical.

HTH Robert

Edited By Robert Welford on 25/10/2018 08:56:48

Edited By Robert Welford on 25/10/2018 08:57:17

[Engine Doctor]

All of the comments in previous post are correct. Add to the list of pros and cons a high quality fuel tank able to withstand the 10 to 13 psi produced by the engine! The YS or Yamada engines I have run are brilliantly powerful compared to similar sized engines . I have the 63 , very old 90 and two 140 FZ that a a few years old. The pump facility is excellent allowing the tank to be placed on the CG with no change during flight as fuel is used. Yes 20% nitro fuel is needed but it's a small price to pay for the power and reliability.

Saito are also brilliant engines but not pumped and IMO not as powerful as YS and it's worth spending on extra on fuel etc as once set up correctly they are brilliant.

It a horse's for courses thing , I don't fly competitive F3a but love flying that type of model and would always plump for the YS to power them and Saito ,OS or Engagement four strokes for anything else.

The real downside for YS is their distributor here in the UK that have the most dismal customer service known to man !

[Robert Welford]

I agree with Eng Doc that the benefits significantly outweigh the downside.

I recently took the plunge and serviced one of my YS engines and it wasn't as difficult as I expected.

Spares are available directly from YS in Japan: http://www.yspower.co.jp/en/index.html

Reasonable price and no postage charge!

 

Edited By Robert Welford on 25/10/2018 10:35:25

Edited By Robert Welford on 25/10/2018 10:35:57

[john stones 1 - Moderator]

Another one for the Y.S fantastic engines.

[Martin McIntosh]

Back in 2000 I built a 2M Dalotel which was only a 60 two stroke size plus 10% for an OS 91 FX. It would scarcely pull it through a loop so up in the loft it went. Some years later I obtained a YS 110 and squeezed it in. What a difference! You would think that the two stroke would have had as much power as the slightly larger four stroke, but not so.

OK, it drinks expensive fuel but is well worth it. Tank is only a SLEC 16oz which lasts for a good 12mins.

I now have 3x110`s, 4x63`s and my original 53.

The sheer reliability of these motors is worth its weight in gold.

 

A long time ago I read horror stories about needing to change the plug every 20 flights and the piston every 100 but this is untrue.

This is still my model of choice for a field visit and the flights must now be in the 1000`s.

Edited By Martin McIntosh on 30/10/2018 19:31:28

Edited By Martin McIntosh on 30/10/2018 19:31:59

[Bob Vaughan]

Dont suppose you would consider an OS 22cc petrol engine? Ive had one in a Probuild 110 size F3a Infinity and it flew with the same sort of performance as the same airframe originally powered by a YS 110s. I found both the 22cc and the 33cc OS's to be very reliable and cheap to run with plenty of power. Just a thought............ Bob V

[cymaz]

I'm with Bob on this.....don't over look using a petrol. Extra battery,yes, smaller fuel tank. Easier to maintain and run.

[Richard Haynes 1]

Petrol... I' did look into this BUT the OS GT15 is the largest engine that would really fit. An OS GT22 is 2-300g heavier than the Saito/Yamada solution as well as being too wide and too long without completely re-designing the engine bay and possibly having to beef up the UC. My research suggested that the OS GT15 might not have the power for the vertical up-lines.