Suggestions please

[Martin Levy]

I have a lovely old Saito 45 Four stroke which I have had serviced and am a keen scratch builder. I'm looking for ideas of what size and weight plane would suit this lovely engine as a 40 size plane would probably be too big as I don't expect the motor will have much power. I was thinking of maybe scaling down a plan to suit but don't know the span or weight that the engine could cope with. Any suggestions gratefully received

[Piers Bowlan]

Do you have any preference Martin regarding the type of flying you want to do as that may influence the size/weight of model and peoples suggestions. For example is your 'bag' scale, semi-scale, sport aerobat, old timer floater etc. A bit more information may help. I see you have a Flair Puppeteer so perhaps you would like something with a low wing loading that flies slowly? I am not really an IC man but I am sure someone will be along shortly with some good suggestions.

[Stumps]

I once had the Saito 45 in a DB sports and Scale 58in Tiger Moth. A love combination for that type of aircraft.

[Denis Watkins]

Mine is a Saito 40 Martin, granted it is not your size, but the model range has been

2.5lb to 4 lb and 48" to 52"

[Former Member]

[This posting has been removed]

[Peter Miller]

Try Ballerina. Flies realy will on an OS SF 40 Surpass.

[Frank Skilbeck]

Posted by Andrew Ray on 27/07/2017 08:07:29:

Posted by Stumps on 27/07/2017 06:45:19:

Something like that sounds perfect or a vintage model. A lovely old Saito 45 is suggesting something more akin to a Piper Cub than a Pitts. I have an old OS 40FS and a 1/6 scale Sig Piper Cub kit to build, that to me is an ideal combination.

I had the a 1/6th scale Sig Clipped Wing Cub with an original OS40FS in it, perfect combination. It's currently in the restoration queue.

Edited By Frank Skilbeck on 27/07/2017 15:32:23

[Jon H]

Flair Nieuport 17 works well with the 45. Also most of the 1/6 scale balsa usa kits will work well too

[Martin Levy]

Thanks for all the suggestions. Plenty of ideas to chew over here

[onetenor]

A 40 sized 2 stroke will also work well in them too.

[John Emms 1]

Talking of the DB Tiger Moth, my old DB Moth 40 that is now with DB Sport and Scale originally had a Saito 40, and that was a perfect combination - the model is heavy, covered in the very thick original silver Solartex, and was flying at close to 7lb. I would suggest any of the older 40 designs will be fine for this Saito 45. By older, perhaps 30 years and more?

Regards,

John

[TartanMac]

I have a couple of aeroplanes that size I want to build. The Super Sportster 20 48" and the plan says it can take up to a 30 class 2 stroke like an is 32sx or Irvine 36 for example from memory it is around 3 1/2lbs with a 25. Your 45 would give it good power for sport flying I think.

The other is a Tony Nijhuis midjet mustang that was a free plan in a magazine. Very nice model. Similar as above.

It depends on what you want sport performance I would want it 4lbs max ideally abit lighter. Over that it will be more like a low wing trainer gentle to fly.

I was going to put my Enya 41 4C in my Uno Wot it is 4lbs 62" wingspan but the Enya turns 10,500-10,800 rpm on a Graupner 11x6 Super nylon my dads Saito 40 turns 10,000 rpm with the same prop and I also get the exact same figures with the APC 11x6. Both are around 370g with muffler. But I noticed after I put the fuse together the Enya is abit too long I need to chop around 25mm off the front. The 40-50 class four strokes is my favourite 4C class. A slim fuse and low drag wing would be good as if you want any speed you will have to go down to 10" prop and I'm assuming you are looking at 10,000 rpm

A 10" prop @ 10,000 rpm makes around 3lbs of thrust

An 11" prop @ 10,000 rpm makes around 4..3lbs of thrust.

I would keep it in that range of weight. If your using low thrust I would go aerodynamic airframe or lower drag higher thrust bigger or heavier plane. But figure out what speed you want aswell . I would not scratch build anything on a whim it is too much time and effort to be disappointed. I bough alot of artf stuff and was disappointed this is how I look at it now. 1to1 thrust to weight is good you need to fly the airframe though to get the performance but if your airframe has alot of character then it is great squeezing out the performance with momentum and being gentle on the moving surfaces to cut down drag and holding the speed up.

[Martin Levy]

Thanks Tartanmac. Plenty of detail there.

[Braddock, VC]

Have a look in this month's rcmw, lovely john rutter aerobat designed for a saito 40, it's a free plan called yonju which is jap for 40.

Edited By Braddock, VC on 31/07/2017 22:53:17

[TartanMac]

Sorry just a correction it is not Tony nijhuis who made the midjet mustang it was Peter Miller from 2006