CLBetten

My Feedback: (16)

I may take the time to test both fuels on my larger engines. I was tempted to buy the 20/20 blend but it's $15 more. Go figure. I don't see the point in paying $15 for 2% more oil. Since the 20/18 was the same price as the lower nitro. I decided to try it and I've used about four gallons this summer. I add a little castor and burn it in my 1/2 A engines. The biggest surprise for me was that the OS ran away from the Saito on a 9X6 but on the 10X6 any small mixture adjustment could likely make them equal. I would guess 13,100 RPM is getting into valve float range on the OS. In my opinion if you're going to run that kind of RPM you might as well use a two stroke. I assume the lower nitro effectively oils more due to the greater volume entering the larger needle valve opening.

CLBetten

My Feedback: (16)

Both of these engines are an engineering marvel in my eyes. The Saito is well used but I think the test was quite fair because the OS is not completely broken in. If anything I set the OS a little more to the rich side. As for the price of glow engines the scale follows quite directly with displacement. I sometimes wonder if the larger, more expensive engines are less expensive to actually build. The machine work on a .30 has to be more difficult than it is on a 1.80 for example.

1QwkSport2.5r

Higher nitro fuel will actually have a higher volume of oil going into the engine because the fuel mixture needs to be richer. Nitromethane has a large amount of oxygen molecules in it so when there's more oxygen present there needs to be more fuel (methanol) to keep the ignition from happening too quickly. The cylinder head temperature will actually be hotter with less nitro due to the lower volume of fuel going through the engine.

CLBetten

My Feedback: (16)

I'll try it again. What you say makes sense 1Q. I'm quite sure I had to go rich on the 10%. I could be mistaken.

1QwkSport2.5r

It will likely be more noticeable on a 2-stroke than a 4-stroke but indeed the mixture will need to be richer on more nitro. I suggest running 10% first, tach it to peak and shut it down. Empty the tank or switch tanks and run the 20% nitro and get the tach on it. I'll bet it will pick up a few rpm if you richen the needle from the peak setting on 10%. The "sweet spot" of the needle valve will be wider on more nitro so it may seem misleading as the rpm likely won't sag per sé on less nitro as the the higher nitro gives you a few more clicks of wiggle room on the needle. When I compare fuel mixes like this, I take note of how many clicks a given engine has rich to lean on each fuel I test.

Sport_Pilot

Actually you got 150 RPM on the 10". That is actually a lot of power as both the thrust and torque required go up exponentially with prop speed. It should be enough of a power increase to notice, especially on a steep climb.

Still the OS did even better on 10%

Mr Cox

This doesn't sound right, to me. Perhaps there is something wrong with the 20% fuel or they have different oil contents...

It is when one increases the Nitro level that one also, usually, have to open the needle valve. With a higher nitro contents one will empty the tank faster...

rgburrill

The specs I see show the OS has higher rpm than the Saito. Isn't the OS a Surpass engine and doesn't that mean it is "supercharged"?

MinnSpin

My Feedback: (40)

"Nothing like the smell of caster oil in the morning."
Seriously.

blw

My Feedback: (3)

I really can't tell much difference in some fuels with the same nitro content. We don't have a large choice around here anyway and I'm not a wine expert either so it's Omega 15% with castor added for me. I do fine with that. Just voicing my fuel use here.

airraptor

My Feedback: (66)

On My OS 30 i have ran it over 14,500 on a 9x6 prop with an aftermarket carb. You can get the carb and carb manifold off the 30 car engine. they even have HD springs for it if you would like to run in 20,000 rpm range. But for most planes that will use this engine that is to high as i think i had to run a 7x6 prop to get that high. Now an 8x4 at 19,000 might pull well too. So in short in the two engines I messed with they were fine in the 14,000 range on the stock springs.

CLBetten

My Feedback: (16)

I flew for several hours today using both engines. I stand corrected. The higher Nitro fuel does require a slightly richer needle setting. I had it backwards on my original notes.

jeffie8696

I wanted to burn some fuel today but it rained and rained and rained,,,,,,,,,,,, took my little 26Surpass to fly too.

1QwkSport2.5r

It's been raining for 3 days here in Minnesota.. Just mixed up a half gallon of FAI fuel to break in an engine but alas the weather blows. Today it's supposed to stop raining but the wind speeds are said to be 25-35mph.

Rudolph Hart

You should try flying in the rain,it's fun watching the prop wash.Where's my truckload of beer and how's the 62 going?

jeffie8696

I have flown in a slight drizzle but not in a full blown rainstorm, I worry too much about my electronics getting wet. If you mean my Saito 62 its on hold as I am busy with helping out some adopted kids

Hobbsy

My Feedback: (102)

I just ran my little .30 on the 10% with 18% synthetic, I think it likes it.

Saito .30
Prop==Bolly 10x5.5
Fuel==WildCat 2/4 10% with 18% synthetic
Max rpm 10,250, more stable shown on tach
Idle was very smooth==2,200= a little
Plug===Taipan 4c.

CLBetten

My Feedback: (16)

Yup, right in there with what I found. The idle on the OS is getting more steady and lower as it breaks in. It's nowhere near 2200.