helicraz

All.. thanks for all your suggestion and recommendations. Though personally I prefered to go for the FS or another Saito .3... I decided not to.

I re-examine plans of my plane... if I should put an engine of that dimension.. my plane is going to look like it has a bad nose job..... the front will be HUGE....

I doubt I have sufficient skills to do much modifications to make it work.. so I ended up getting a .15LA instead, following the recommendation of OK model.

Cheers all.

EASYTIGER

My Feedback: (119)

On that subject...I have talked to several manufacturers about this.
Here's the general consensus:
There is not a big enough market to merit making one, and the problem is a smaller engine will cost MORE than a larger one, and this is untenable in the marketplace. After satisfying the few hundred nuts like you and I who will find such an engine incredibly interesting, then they are stuck trying to sell thousands more to people who are just going to look and wonder why on earth they should pay $300 for a four stroke instead of $50 for the two stroke...
I have seen some .15 four strokes built in the Czech Republic, they are pretty cool, but not exactly tops in power to weight...
Maybe this will change someday when some chinese company sees enough profit in a tiny niche like this, but at present, OS and Saito and Enya can't see the sense in the numbers.

Bipe Flyer

BLE,

I think you're probably right.

Helicraz,
You'll find that the .15 LA is much quieter than the AP .061.

Bipe Flyer

Maybe the scale is perfect and the missing 6g was due to air bubbles.

My FP has a remote needle, which could add a little. It is also well used, so I wonder if some exta baked on castor contributed to the weight.

helicraz

I certainly hope so.. the AP0.061 was screaming almost as loud as my OS.18tm, leaking everywhere during the first run. And on its subsequent runs, after I can't even get it to suck fuel into the engine. Already sent it to the recycling center... [:'(]

B.L.E.

Just for grins, I put a O.S. 10 FP on my scale and it weighed 160.2 grams. Oops! No glow plug in the engine! I'll be right back........................OK, I threw a OS #8 glow plug on the scale and now it weighs 163.2 grams. Only 20.1 grams less than a O.S. 15 FP!

B.L.E.

I agree, a small engine has the same number of parts to assemble as a bigger one, the parts have to be machined with the same or possibly with more precision. The only area that is less is the amount of raw materials, big deal! What does aluminum, steel, and brass cost anyway? BTW, wasn't the Cox .010 TD one of Cox's most expensive engines?
A lot of the cost savings in the smaller engines comes from using bushings instead of ball bearings and air-bleed instead of two needle carbs. The carb alone for a high end pattern engine probably costs more than a complete budget trainer engine.

When I built a 2/3 sized .15 powered version of a .40 pattern plane, I found it ironic that this plane cost me more to build than the .40 sized version did, thanks to the premium price of micro servos and recievers at the time.

Bipe Flyer

I know it's impractical, too expensive and there isn't enough marked, but I wish someone made a .10 or smaller 4-stroke too. While we're at it, I wish for world peace and to win the lottery. I want the 4-stroke first though.

SGC

Heres a small batch of Russian Mk17 .09 diesels converted to 4st, there are some lucky owners somwere!
Stewart

lildiesel

Very interesting conversion. I wonder if there would be enough demand to get P.A.W. to do a 4-stroke conversion of their excellent twin ball bearing .09 diesel?

BTW, the R/C P.A.W .09 would be a good choice for the needed noise reduction without overpowering or increasing the wing loading of the plane that started this thread. With an 8-4 prop it haul the plane around with some authority while a 9-3 would be almost as quiet as an electric. A few inches of tubing off the supplied muffler would make the engine even more quiet.

I think what the neighbors are objecting to could be the "tearing" noise of the small prop on a 1/2A sized engine at very high rpm. A diesel turning a larger prop (usually 1 or 2 inches greater diameter than the equivalent glow) at a lower rpm will take care of a lot of what non-modelers object to in the engine noise and still produce the thrust necessary to fly the plane.

Bipe Flyer

That is very cool Stewart. I wonder if someone could produce after market upgrade kits.

buzzard bait

I love my OS .15 FP. It runs beautifully and quietly with a 9x4 prop cut to 8 1/2. It would probably swing the full 9 inches just fine and be even quieter, or use an 8x5 or even 8x6 if you want some speed without high revs. I think it will be perfect for your purpose.

I never put a starter to it. Give it ONE choked flip after you get the fuel up to the intake (more will flood it), a couple more unchoked flips to get the fuel into the cylinder, then apply the glow battery and flip the prop. All my FPs, .10 to .40, start instantly this way. Enjoy! Jim

blacksheep

My Feedback: (1)

Today was the maiden "fright" for my Combat Corsair with its Saito 30 up front. It didn't seem as fast as my friend's Mustang with the OS 25. Maybe it was just the "mosquito-on-steroids" sound of the two stroke that made it seem faster, but more likely the fact that the 30 FS was not broken in completely or the fuel or the prop size. Which begs the question, just what is the optimum prop size for the Saito 30 when it is to out perform (if it ever will) the OS 25. I used 12% Nitro fuel with significant castor and an APC 10 X 5 prop. I am going to try Wild Cat 20-20 when the engine is ready.

As an aside, the Saito 30 is easy to start and runs reliably, sips fuel, and is great fun. The GP Combat Corsair is a real winner with flight stability and solid maneuvers for a small bird and has an excellent sport scale look. Good job of engineering too. You can't beat the price either.

piper_chuck

My Feedback: (12)

It's hard to imagine that you'll get a .30 four stroke to out perform a .25 two stroke in any areas other than fuel economy, or (lack of) noise. The 4 stroke is heavier and doesn't have the HP. However, I've got 2 FS-30s that aren't being used and I think the Corsair might be a perfect choice for one of them.

Bipe Flyer

My Saito .30 weighs less than my OS .25 FP with the mufflers. It can spin a lot larger prop than the .25 too. Even though the actual HP is less, the 4-stroke will put out more thrust due to the larger prop, at the cost of speed.

blacksheep

My Feedback: (1)

I am not unhappy with the Saito 30 even if not as fast. It pulls the Corsair smoothly and surely and is really not too heavy for the GPCC... in fact it might be a perfect weight. Guess I will just have to refrain from combat with the Mustang and .25 combo, or do circles and hope it falls out.

This is a fun airplane that can be taken on vacation or kept in the van when the impulse to fly hits. GP has a real hit on their hands.



P.S. Has anyone come up with a suitable launcher for this craft... holding a radio and throwing a plane gets a bit messy.

ClemenTang

According to Saito website the engine is 0.5HP and top rpm=12000. Guess peak HP at 11000 rpm try to load it with a 8" prop with a pitch to allow 11000 rpm at full throttle. Try an APC 8x9, 8x10, 9x8 or a 9x10 trimmed down to 8.5x10. A high pitch would give it some speed but too small diameter won't pull it.

Clement