I am building a Curtiss-Wright Cw1 Jr that is was originally planned for electric power. I, however, am installing a Saito 30 on this plane. Here's my predicament: The engine is mounted on the top of the wing, and the only place I can mount a fuel tank is in the fuselage, which is about 9" directly below the motor. I have played with the idea of using a header tank, but I am not sure if there is room for it.

My question is: Will a Perry oscillating pump suffice for my needs of moving fuel directly up about 9"? The plane is FAR from aerobatic, it is a slow, lazy flyer so it will not incur too many "g's" under everyday flying conditions

I have never had the need to pump an engine before, so I haven't a clue as to what the heck I am getting myself into! HELP!!

[link=http://image.rcuniverse.com/forum/upfiles/126578/Hc92321.jpg]pic1[/link] <----what the plane will look like
[link=http://image.rcuniverse.com/forum/upfiles/126578/Dx66324.jpg]pic2[/link] <----what it looks like now, the fuel tank will be mounted in front of the cabanes.

Hmmm....tell me why you're not doing it electric again?



Oh, and is it a kit you started on your own - something you got from someone else or scratch built? Just curious - looks neat.

I don't have a solution for you, but that really does look like a nice build so far!

JC, don't even think electric, the .30 makes plenty of tank pressure with a check valve on the pressue tap to operate a Cline regulator. Just turn the fuel nipple on the carb straight down and hide the Cline beneath the carb. It does not matter which way the fuel nipple points on the .30. I have an extra .30, I'll play with that idea and post a pic.

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Ditto. I'd go electric, although the model looks a little heavy in its construction for an electric. I would save the Saito .30 for something a bit more conventional with a lighter wing loading and a secure engine mount to spread the vibration better than through and into the wing. Just my way of thinking.

Without sufficient/proper bracing, that thirty is going to shake things apart easily. Sometimes a .15 two-stroke is a better choice on frail structures with twice as many power pulses of half the magnitude of a four-stroke. Still, I'd probably go electric.

Were I to use a glow engine, I would forego the stock appearance and mount the fuel tank in front of the engine in a nacelle of my own fabrication. Put the tank stopper facing forward and you should have no problems with fuel draw, etc. Just keep the tank centerline even with, or below, the carb spraybar, even if you have to raise the engine's position to do it.

Small models are weight critical. Carrying extra hardware, such as pumps, is best avoided if at all possible.

It is a good looking model. Keep up the good work.


Ed Cregger

ED, I'm not trying to be a bad guy but the .30 probably runs smoother than an electric and increases the fun by a factor of 1000.

Either the Perry pump or the Cline should work. The Cline may be easier to set up, but the Perry costs less. You can also use the Perry VP-20 regulating pump, but you would need to bypass the pressure tap so that the excess crankcase oil will flow out.

Good idea to read the instruction manuals before making your decision.

http://www.perrypumps.com/instructions.htm

http://www.billsroom.com/pcfs/produc...uelsysdesc.htm

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I'm with you on the fun factor aspect of the Saito .30. I just think, judging by the pictures, that the model is a bit small for it and that the engine position will present a recurring vibration failure point. I could easily be wrong. In fact, I hope I am.

Even if one committed to the .30 and found my prediction to be true, it could still be easily converted to electric power at a later date. So, other than a bit of weight gain and work lost, there is nothing lost in proceding with the Saito .30.

It would take one horrible electric motor to shake anywhere nearly as much as an IC engine, two or four-stroke, don't you think?


Ed Cregger

Submike - the plane is a scratch build from plans by Ernie Heyworth (Super nice guy too!!). I asked him [Ernie] about putting a glow engine on it and he said that a couple people in his area have mounted 30's on them with a little reinforcement. It will have a 53" wingspan once i put the wing tips on. AND I didn't go electric for a number of reasons: too easy, too clean, too quite and most of all for Hobbsy's reason, the fun factor!! [:-]

Hobbsy, thanks for the suggestion. So are you saying that instead of pressurizing the tank, just leave it vented using the pressure for the pump and use a cline regulator instead of an oscillating pump? remember, i have never used a pump before so i have little clue as to what i am getting myself into! a picture would be greatly appreciated.

Other than that, i have set the motor on top of the plane and it appears to be quite top-heavy which is a bit worrysome. And Ed, i have thought about the vibrational forces from having a 4-stroke sitting on top of the wing, and that also worries me. I have taken some precaution however. The cabanes are fiberglassed in, the ribs that the cabanes are attached to are reinforced as much as i could and will be reinforced more once i glue the wing together and get the wing joiner in. It will also have struts on the wings...so hopefully all this will spread out the vibration as you suggested.

BTW: Submikester, guess who gets to walk out there with me when i maiden it! you thought I was nervous before!! [sm=bananahead.gif]

JC, the Cline regulator comes with a small check valve that slides into the pressure line near the muffler pressure tap, makes most tanks bulge a little. The regulator is a demand regulator and only lets fuel flow when the engine demands it. I just ran my Saito .30 with a Cline right beneath the carb, I made a video of it but my computer decided it can't see the Camera, so I gotta work that out.

I'm listening to a Slim Dusty CD so I wont' throw the PC or the camera through the wall.

Well, I can't wait to get this engine running for you.

To use a regulator (which I have used before for tanks that are too high) the general goal is much like a pump but it is gone about a different way. Instead of pumping the fuel with a "fuel pump" the tank is pressurized and a check valve is inserted inline to the muffler pressure hose. Pressure comes from the muffler but cannot go out that way, this forces fuel out the fuel pickup line. Without a regulator it would likely cause the engine to be over rich. The regulator restricts the fuel flow to the desired amount ensuring a constant flow of fuel regardless of tank position. I think this might work for you as the 30 is a pretty small engine, on a larger engine a pump might be a better solution due to the larger venturi on the carb having less suction (negative pressue on the fuel pickup line).

The pump, of course you know how that works.

Cline or Iron bay make regulators - I have an Iron bay in my corsair (which I still haven't built yet since the replacement from Hobby People) with the Magnum 91 inverted. On the one flight the original had I experienced excellent performance in the form of a great idle and a great transition as well as good full throttle performance.

and of course I expected I would be walking out there with you - what color will this one be? Silver again?

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I couldn't imagine you being a bad guy, Dave.

This is one of those brainstorming days for me. I tend to be a bit contrary on these days.

We're just talking here. By sundown, I may have changed my mind another fifteen times or so. That's why I don't get much done these days. Too much thinking and not enough doing. <G>

Sorry I can't be of more help to the OP. Then again, he put his query here so we could all chew it over.


Ed Cregger

The only way a Saito 30 could be more vibration free than an electric setup would be if things on the electric setup were out of balance. I know on my brushless setups with balanced props and such you can barely notice any vibration.

Well...that is unless a Saito 30 is magic.

After some research leading to more of an understanding of regulators, I really like the idea of them! although the price isn't too pleasing. I guess i just have to suck it up. Is there any real difference between the Cline and Iron Bay regulators?

Submike- the colors are cream and dark,metallic red. And yes, i will be asking you for help on tuning this one! An engine with a regulator, mounted on top of a wing with a pusher prop...shew, that's a lot of new stuff to handle for one plane! Thanks in advance!

As I said, I've used the Iron Bay regulator with good results. I'll have to work on my corsair to show you how it is setup. It's still in the box, maybe next week.

I won't be out this weekend as we're heading to Arizona to visit the mother in law. I might try to go flying Monday morning though...if I can get away from work...it isn't looking promising.

http://www.ironbaymodelcompany.com/W...cessories.html

JC, I'll run the .30 today with the IronBay so as to be fair, the IB might just be easier to mount horizontal beneath the .30 carb, I'll check it out.

get the cline. I've used them, they work. if you're lucky you may get a perry system to work.
but it'll never work as good as a cline regulator

Hobbsy, did you ever get a chance to run the 30 with the Iron Bay regulator??

I have done more research on the two regulators...it seems as if the Cline is made of plastic and the IB is made of aluminum. But the IB has that MASSIVE fuel inlet!! Is the Cline lighter in weight compared to the IB??

on top of all that, i have no idea where to get the IB regulator, their website seems a little shoddy