w8ye

My Feedback: (16)

Normally yes

most people consider it hot if it sizzles spit but I sorta go by the smell and smoke off the head etc.

Actually water boils at 212F but the head temp is better around 280F

Kodiakflier

sounds like some folks got in on this new saito before the bugs were all worked out. just recently found a seawind 60 for great price and looking for a gasser to power it. much rather use gas mix as nitro fuel runs about $38 a gallon here on the rock if you can even find any! my only thoughts as to the fg20 vs another gasser is the top boom mount of the engine on the seawind. saito says fuel tank mounting can be at cg, but sounds like maybe soom probs with weak fuel pump. any advice about this or use of electric fuel pumps would be nice. probably be a couple months before i buy an engine, so the more i can figure out before then the better. if anyone has a seawind 60 w/ a gasser let me know what you are running for power etc. thanks

w8ye

My Feedback: (16)

There's no way the pump in a FG-20 carb will support a tank mounted on the CG let alone a engine up in a pod with the tank on the CG

One thing about the FG-20 though is that you only need a 8 oz tank. Is the pod big enough for a tank that size?

laryboy

My Feedback: (2)

w8ye........fg 20 mounted inverted.......tank center about 1 1/2 inch above center of carb . where should tank be ?

w8ye

My Feedback: (16)

If it is an aerobatic or 3D plane the tank should be centered on the needle valve

Timbers

My Feedback: (3)

I flew the plane again today, one 15 minute tank and one 5 minute tank. I tuned the plane up on the ground for max RPM at full throttle. Flew for about 5 minutes before the sputtering started, so I stayed out of full throttle while up in the air. Plane flew pretty good, just did the sputtering once in awhile or when at full throttle.

I've been told to come down, richen or lean out the engine a click or two then go back up in the air...

So if the engine is sputtering, that means its probably getting richer in the air right? Will this engine sputter because it is too lean? From what I have found on the ground if it is too lean it dies at full throttle, and its definately not doing that... So maybe come down, lean out one click, then head back up?

...Tim

w8ye

My Feedback: (16)

That sounds correct to me

At least try it and see what happens. It's hard for me to hear it over the sound of the Internet

Kodiakflier

Thanks for your input, dont know if pod is or not, still waiting for plane to show up. not sure but pod is the instructed local for tank for nitro engine. Aaron

Kodiakflier

W8ye, mostly want to avoid changing cg while in flight. do you or anyone else have any exp with electric onboard fuel pumps? maybe a very small (1 oz. or so) tank with return to main? looks like plenty of room in boom behind fire wall from pics ive seen. mostly im just preplanning build now so i have some idea how to procede when plane is in my sweaty mitts!!!

w8ye

My Feedback: (16)

The change in CG situation is very minimal. For one the engine only needs a 8 fluid oz tank which only holds actually 6 oz of gasoline. You would never notice the difference in CG change.

If you do use a pump, it should just pump up to a header tank and the overflow return to the main.

karolh

Can you explain why you say that a 8 oz tank only holds 6 oz of fuel.

Karol

w8ye

My Feedback: (16)

Karol, you are one of our resident authorities. Take a 16oz fuel tank and see how much gasoline it will hold? I bet you cannot get more than 12 -1/2 oz of gas in it? I made an error in the previous post it is 6.25 oz

karolh

An authority I think not, I just try to help others where I believe I can. Talk about taking things for granted as I never thought there would be a discrepancy between a stated tank size and it's actual holding capacity. Well you really do live and learn and thanks for pointing this out to me. Just makes me wonder how many of us are aware of this.

Karol

w8ye

My Feedback: (16)

To most people you are the authority so keep up the good advice what ever you are doing

A gallon of water is 128 oz's and in turn everyone uses this as a form of volume measurement called fluid oz. A gallon jug or can will only hold about 100 actual ounces of gasoline when full to the mark. A Dubro or Sullivan 16 oz tank is 16 fluid oz capacity. It will hold 16 oz of water but you start trying to put gasoline/oil or model airplane glow fuel in a empty Dubro 16 oz tank and you are only going to increase the weight by about 12 1/2 oz when it is full.

I was taught this fluid volume deal in school but had forgotten. Someone over in the glow engine section reminded me of this about 4 yrs ago.

Timbers

My Feedback: (3)

So gasoline weighs less than water?

I remember a few years ago I bought 5 gallons of pure nitro to make some fuel with. I could barely lift the 5 gallons of nitro it was so heavy!!! Nitro is very heavy.

Kodiakflier

   my understanding of gas/etc vs water is the volume is the same but weight varies depending on what the liquid in question is.

mike early

I've been a little confused but didn't try to think about it. But I need to get this straight:
We are talking about fluid ounces. 16 ounce fuel tank can hold 16 ounces of water but only 12 ounces of gasoline?
By the very definition, when you fill that fuel tank up, you will have 16 ounces of gasoline. Now I realize that a weight ounce is an entirely different animal.
One good thing about the metric system is milliliters is always milliliters.... 470 ml of water will fit inside and 470 ml of gas will fit inside.

RCHubbub

Same situation whether it's metric or not.

It comes down to density. It depends on the blend, but gasoline typically has a specific density of 0.7 which mean that for the same given volume, gasoline will only weigh 0.7 or 70% of what water would weigh.

I'm rounding for simplicity, but a 16 fluid oz container will hold 16 fluid oz of water which will weigh 16oz, but that same container holding 16 fluid oz of gas will only weigh 11 oz.

And in the metric system, a container that can hold 470 ml of water will weigh 470 grams, but if it held 470 ml of gas, it would only weigh 329 grams.

mike early

But when speaking of gasoline quantities, does anyone ever use weights? Only volumes, right?

RCHubbub

Typically yes, but if you are going to change tank sizes or move the tank around in relation to CG, then one might find it useful to think in weight.

For example, if you buy a plane with a stock 22 fluid oz tank intended for glow fuel but want to convert the plane to a heavier gasser and go to an 11 fluid oz tank, one might think they would be reducing fuel weight by 11 oz. But 22 fl oz of methanol would weigh about 17.6 oz, and 11 oz of gasoline would weigh about 8.25 oz, so the saving in fuel weight is not 11 oz but more along 9.4 oz.

So this all boils down to that a fluid oz and a weight oz are only equivalent when dealing with water.

w8ye

My Feedback: (16)

Specific gravity of liquids relative to water

Water 1.00

Gasoline typical automobile .739

Motor oil typically .8

Methanol .791

Nitro 1.13

Ethanol .787

Castor oil .959

karolh

It's all quite clear now.

Karol

R/C Foolish

My Feedback: (6)

You guys are all worrying over an ounce or less. The fact is that this motor is still overpriced, poorly designed and not supported by Saito or Horizon. Mine runs ok but just barely, new plug, new ignition, new carb, sent to Horizon - no difference. Not a lot of power compared to the 125 glow, only runs decent with a 15x6 prop. I really don't have anything good to say. Everybody that is still unhappy about their motors should be posting daily until Horizon and Saito get the message!

R/C Foolish

w8ye

My Feedback: (16)

Mine do well with APC 15 X 8 and even better with a APC 16 X 6 prop. I also have two Saito 125's. There's not much difference in the way they run power wise. The FG 20's will idle much lower.

blackmonte

My Feedback: (11)

I have read pretty much through this thread and was dissappointed to see these problems with the saito fg20. I was considering one for a future purchase because of cheaper fuel but still have
the 4 stroke sound. But after reading this now i'm unsure for amount of money involved. But how many of these engines are out there and how many problem engines have there been? I know
that RC Foolish and Sailfish(I think) and another member have had terrible problems and I think that with the time and trouble they have went through with Horizon, shipping, buying extra parts
etc. they should have exchanged engines with them or at least gave them the option for a full refund plus the shipping involved no questions asked. I hope this is only limited to a small
percentage of engines with problems as people tend to post more if they have a problem rather than not have a problem. And I mean no disrespect to any that have had problems, I feel your
frustration. I'm just glad we have threads like this that informs other members of potential problems. Thanks all for the info and keep us informed.