i need help this what i'm up to . i'm building don smiths b-17 the tanks are in the wing about 12" from the os 91 4 stroke engines. i got 4 perry pumps for it will they work with this setup

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If they are VP-20 pumps, yes, they will work just fine.

If they are VP-30 pumps, trade them in for VP-20 pumps, or be prepared for a lot of plumbing work.


Ed Cregger

There's no reason why they cannot.

Probably the best way would be to plumb them up in the by-pass manner with a return line back to the tank? The pump gets fuel to the needle valve for the engine to use. What isn't used, goes back to the tank.

http://www.perrypumps.com/Pump%20and...s%20System.pdf

Dom...it's Tom...how ya doin'?
I can't get the dang pdf to open for me? But if that's the one I think it is, it't the one I was telling you about on the phone last night.

ok tom i'm even thinking of selling the os four strokes and going with 91 2 stroke this is holding me up from finshing the wing

You could also go with 2 strokes...but with the tanks as far away from the carb as they are, you're still gonna have to run either pumps or a regulator set-up.

Try a search for: Cline regulator, and Iron Bay regulator just for the heck of it...

Ed...if the engines are quite solidly mounted, will the V-20 pump(s ) still work adequately? Don't they need to shake around somewhat to be effective?
The nacelles on the B-17 are big and fairly "solid" structurally and the engines/mounts aren't going to (better not! ) shake or vibrate very much...

That Perry pump (VP-30) doesn't need the engine to shake in order to pump fuel. It gets pulses from the engine via a pressure nipple. Those pulses work a diaphram back and forth to pump your fuel.

The VP-20 DOES need vibration or oscillation back and forth to pump. As Ed already said, the VP-20 would normally be used on a 4-stroke engine such as your .91 But, it needs to shake back and forth to pump fuel and if your firewall and motorbox is going to be that rigid, I think you might need to go ahead and trade them off for some VP-30 regulators.

Proptop has a good suggestion about looking into the Cline or IronBay regulators. They work pretty well. They work DARN well. Same or similar plumbing, but a much cleaner and more consitant result than a Perry IMO More reliable and trouble free. Tune it once really good and tweak it in just right on the low end. Then you forget about it and go fly.

My only issue with the Cline and IronBay regulators is that you have to have an engine thats broke in pretty good. Not a used engine, but you definetly don't want to hook up a Cline untill you get about a gallon of fuel through each of those OS .91 4-strokes. I run all my engines just a tiny bit fat for about 1 or 1.5 gallons. Even on the low end. Not slobbering, but just a tweak rich. I find that my ABC glow engines don't really like to be leaned out to the max on the low end untill they are solidly broken in.

Okay, so when you put a Cline on an engine--that engine better be good and solid. Trying to run the low end rich has caused me fits a couple times untill it finally hit me in the head and I figured out why they wouldn't run. The Cline is such a precision device--it is so finely tuned--that any amount of overly rich on the low end just causes them to flood the engine. You need to tweak that low end needle down to the knats --ya know-- and get it set as perfect as you can possibly get it. If you don't, you'll cuss a Cline for the rest of your life.

My glow engines don't seam to want to be leaned down that far on the low end untill they have passed a fair amount of fuel. So, I made the mistake a few years back when I first tried the Cline--I was hooking them up to brand new engines and was NOT happy with the results. It finally dawned on me and I ran the engines in a mule plane for a gallon to break them in. Took them out of the mule and mounted them up in my flyer. Set the Cline and it was all smiles after that.

Just passing on my experience. You can do it however you choose. [8D]

Here's a link to the Cline Regulator:
its such an obscure website, you'll never find it if you search on giggle or any other search engine
http://www.billsroom.com/pcfs/

And Ironbay:
http://www.ironbaymodelcompany.com/W...or%20Main.html

Good luck. Lets see some pics of the plane.

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If you were to take a large anvil and mill an engine mount into it, the VP-20 pumps would still get enough vibration to operate IF you attached the VP-20 pump to the front of the engine right in front of the pushrod tubes. The aluminum crankcase moves quite a bit even when the bottom is firmly attached to something super solid.

In a model with so much room inside the nacelle, why do the fuel tanks have to be so far from the engines? Retracts in the way?

Like others, I'd rather go with a Cline or Iron Bay regulator system. The low end is infinitely easier to set and more reliable.


Ed Cregger

The main gear wheels are quite large...they come up right into the area normally occupied by the tank.

I suggested the V-30's because I have a lot of experience with them and the backplate Perry pumps since the mid 70's, and remembered reading of the success of a few that used them with Saito's.

I don't have any experience with Cline or Iron Bay regulators though, other than what others have written here about them.

Do you think the V-20 would pull fuel over a foot away?

While I have no problem with Perry pumps as others do, I would be tempted to use the regulators rather than either of the Perry pumps. With just one tank and four engines you would only need one regulator and tee's for four fuel and four pressure lines.

I thought it was basically the same as the regulator in my weed wacker? It may be better than the regulator in the Perry pump, but I doubt it is that much more accurate. The main differance is that it regulates at slightly below atmospheric instead of postitive pressure, which may be better for many engines.

The best way to prepare an engine for a regulator is to set the engine up on a test stand with the tank in an ideal position. Then mount the regulator and you'll be pleasantly surprised to find that the needle settings will change very little, if any. If you break the engine in with the regulator on it, it will have the ideal settings from the git go.

I have not actually seen Dominick's B-17 yet...but he's told me a lot about it on several occasions. He says that there will be a tank for each engine.

I was at first thinking of perhaps a small (2 oz.? ) header tank mounted on the firewall...but I guess there's not enough room?

The V-30 / Saito installation I was thinking of was a 1.50 in a Funtana S90 and the guy (sorry, can't remember his handle ) said it worked wonders for reliability and he got more power as well, because he could then run it w/o a muffler.