Originally Posted by mlj3

I brought a tweety 25 last summer just for a OS 26

I would love to build a tiny pattern plane. I have also considered dropping one in the Eflite Leader 480, this guy seems to have too much engine on it with the Saito 40a, but that still seems like a reasonable combo. he claimed it came in at 45 ounces dry on RCU, the .26 should do great on one

leader 480.MPG (3 min 45 sec)

Originally Posted by aaronredbaron

that makes sense, I assumed it was probably something along those lines. What a shame!

My .26 is not happy with the 11x3, it sags and gets hot and can't hang in there, but it sings away with a 10x4, I would have thought they would have about the same load

How much nitromethane are you running in your fuel? It might work better with less nitromethane in the fuel. I have been running 5% in mine.

Originally Posted by earlwb

How much nitromethane are you running in your fuel? It might work better with less nitromethane in the fuel. I have been running 5% in mine.

hu... I figured it would like higher nitro.. its somewhere around 20% (30% heli mixed with 10% plus some extra castor) I'll have to try that...

I've always had success with 5% nitro in everything from Cox 049 up to 90 size.

When I had the 26 on a Whimpy with too much prop, I never tried reducing nitro. I may have been using 10% at the time because I bought whatever they had at the store. But that never occurred to me at the time. I just lightened the propeller load and the engine ran cooler, used less fuel, and flew the plane better. At any rate, you can definitely use less nitro.

I have only had a couple three four strokes over the years that needed more nitro to run right. A couple of ASP .62 engines and maybe a RCV .91 engine (I am not sure at the moment). The ASP.62 engines seemed to be low on compression and maybe when the rings are fully seated it might change. Anyway 5% nitro works for me. Adding more nitro and the engine had high compression is like advancing the ignition timing. Thus it winds up overheating from detonation when the engine is loaded down more with larger propellers.

What a great thread! I have always loved the sound of small 4-strokes. I recently bought a new Saito 30 from an Australian dealer on eBay. My Sig Kadet LT-25 is about half finished. I hope they will make a good match!

Perfect match

At the time I built my first LT-25, around 1996, the hobby shop didn't have a Saito 30 on hand. I opted for the OS 26 instead. Sure wish I had waited and scored a Saito 30!
The OS did run fine but even I would have liked a bit more steam on tap.

I sold the plane to a fellow I work with and AFAIK, he is still flying it.

I got a nice flight in today at lunch with my Timber, good times!

Nitro Timber lunch break flight! Powered by OS .26 four stroke (3 min 16 sec)

ARB that Timber flies great with that 26fs. Looks like your having fun with it.

Garycee, I liked my LT-25 I built back in 99 and figure I will put a Saito 40a in the next one I build. I flew my first one with a OS 26fs, like you did, it was enough but a little more never hurts. It is a large enough airframe to handle the extra power.

Originally Posted by wingtips

Garycee, I liked my LT-25 I built back in 91and figure I will put a Saito 40a in the next one I build. I flew my first one with a OS 26fs, like you did, it was enough but a little more never hurts. It is a large enough airframe to handle the extra power.

Yes, as I recall, a bit tight in the engine bay but it was doable. I made up a 90 degree dual tube feed through bulkhead fitting for the fuel and vent connections That really helped at keeping things tidy.

Let us know how the 40 fIts. I would consider building another in the near future . It would be a matter of choosing between the 30 and 40 Saito. Already experienced the small OS

Dear Gary Cee & Fellow RCGers:

The PIPE Here...over the years, I've managed to get a used HP VT-21, a bought-brand-new Saito FA-30S (the enclosed valvetrain one from about 2007) that's "relatively" broken in, and a never-run Saito FA-40a.

I've already CAD-sketched up the Saitos, and I'm partly into the similar sketching of the VT-21.

The FA-40a drawing is shown below with an inch-scale for reference. drawn entirely from measuring my own example:



while the CAD drawing of the FA-30S (also with an inch-scale) is shown immediately below, also measured from my own example.



As I've got the JPEG-scans of the plans for Ace RC's old All Star biplane on my desktop CAD PC, I'd definitely do that one up for the VT-21...

...the FA-30S will be going into my own version of what a 54"/1.4 meter wingspan Telemaster would be like, the "Elyu 140"...that same design's also meant for 4S1P A123, LFP-celled electric power for VERY early morning flights...



...with the new, "Mk-II" version of my ABBABIPE Jungmeister (from my own CAD-drawn plans) getting my FA-40a mill, for a truly "sparkling" 42 inch/1.07 meter wingspan small RC Scale aerobatic bipe, "just small enough" to take to just about any RC field, just as I did with the original in the early 1980s, on a number of occasions (even to OLD RHINEBECK in 1984!)
.
It IS nice to have a small collection of those "endearlingly small"-displacement four-strokers...at least I've got what airframes each of mine's going to go in someday, already decided... !!

Yours Sincerely,
The PIPE....!

I threatened to post this once completed. The Saito has the same mounting dimensions as OS 25-32 and clones which made this a relatively easy swap. For now, the throttle pushrod makes a 180 and then a 90 +/-. Not easy to see as the picture is somewhat out of focus. I'll be refurbishing this 10 year-old airframe soon with new covering, landing gear strut shimming, hatches for the fuel tanks and I'll re-route the throttle pushrods at that point. I've included "before" picture also.

Flew her today - 3 times. It was fast with the 32 SXs and almost as fast with the 4-strokes. Due to clearance issues, I have to run 10" props, so I used 10x7 MA. The Saitos will rev these over 11K! Might have to consider 10x8 MA or 10x7 APC to increase the load somewhat.

Love the small 4-strokes!

Jim

ps. the shirt was my birthday present from my daughter

Dear SRQFlyer:

The PIPE Here again - when someone mentions a TWIN four-stroke-powered RC aircraft, I always mention Finland's Ilkka Klemetti, and his magnificent Junkers Ju 88A RC Scale warbird in 1/10th scale...

the VIDEO of this model in flight is something to watch, and especially for the SOUNDS the pair of FA-40as make !!

Yours Sincerely,
The PIPE....!!