well it finally happened... I'm slapping together an ARF that I CANNOT get the fuel tank even CLOSE to the carb centerline. In the past I've ran into this problem and fixed it by adjusting the tank height or side mounting the engine... no joy on this plane... SO I'm stuck with what I know will be nothing but engine troubles or I pump or regulate(Cline or Iron bay) the engine... only other option is buy a YS 63... seems the plane was built around this engine.

I'm not really thrilled with buying a new YS when I have a perfectly good saito 72 sitting on the self that will fly the poo out of this plane... if the damn tank was the right height. I've never had the need for a pump like the perry VP-20 or regulator like the Cline or Iron bay. Considering the tank will be over 1 inch above the carb centerline what would be the better option... pump or regulator? any major draws backs using either system? I have more than enough room to mount either according to the instruction... I'm just not sure what the better system for my problem would be.

John

JSN...what kind of plane is it, and what type of flying do you anticipate? An inch above the carb isn't ideal, but it's not likely to ruin the show on a Cub or the like.

Details?

A pump/reg is one option....as is a small header tank installed at the correct height for a fraction of the cost.

I think we have arrived at a time in modeldom when most manufacturers are going to have to consider equipping their engines with some kind of real fuel handling system.

I do not think that all engines need to be supercharged, but that isn't bad if it doesn't cost much more.

I would rather see them go with geared pumps and a regulator, personally. That, or find a replacement for the silicone membranes in their pumps/regulators that doesn't deteriorate so quickly, or are susceptible to damage from chemicals other than fuel (various lubricants). The day of suction feed engines is coming to an end for many aspects of our hobby.

Well...perhaps, but the only reason I chimed in on this one is because (horror of horrors) I have a near-antique GP Cub that has been flying for 13yrs with the fuel tank a full inch above the carb centerline. I simply installed a small tank. What the heck...with the OS .70, it takes off at 1/3 throttle, and cruises at a fast idle. With an 8oz tank, you can fly until you need a shave, land, and still have half a tank. Never had a problem. In other types of models...tank position is more of an issue.

IMO...ARF mfrs would do well to engineer their products correctly.

'Race

Race,

The plane is a Worlds model Groovy 3D... I had some credit at my LHS... and the saito at home... one impulse buy later it's on my bench

The engine HAS to be mounted inverted or I leave off the cowl and mount it up right... not really a good option. I can't bring the tank any lower due to the "shelf" the landing gear is mounted on... that extra 1 1/2 of fuse would give me the area I needed to lower the tank. I can't lower the engine due to thrust line and the cowl. I though about the header tank... will this do me any good? I though the header tank was only good to help out foaming/vibration bubbles on my heli and to keep the clunk in a constant fuel supply... will it also help with a tank thats WAYYYY to high? I though that even when you use a header the engine still see's the main tank as it's supply.

John

Ed,

I agree that the manufacturers need to address this issue. I've built more ARF's in recent years than kit's due to work and family... a full time job and 3 teenagers at home take up most of my free time... I either slap together an ARF and fly or build... I'd rather fly I've had to adjust the tank height on most ALL the ARF's I put together, I'd rather do what I know is right the first time than get out to the field and have trouble because I didn't move the tank to the Centerline or very close to it. It's been, in most cases a simple fix... why the manufacturers don't just do it right the first time is beyond me.

John

JSN...I don't know for sure. A header tank is certainly a low cost (<$5) approach to try and test. It seems to me that the header tank would help mitigate any static fuel pressure (head pressure) issues with the fuel tank being too high, AND....it would give the engine an unchanging fuel source from which to draw from regardless of your airplanes attitude.

IMO...it's worth a try.

'Race


PS: Is it possible to mount the engine "sidewinder"???

This is the best of all positions AFAIC....

Race,

It is possible to go "sidewinder", I've done this on a few planes to help tank position. On this plane however I'll have to BUTCHER the cowl...most of the bottom right hand corner will have to be removed to clear the muffler...of course I'll need a large hole for the head to clear... I'd rather not do that...with the side mount the tank would be about 1/4 inch low! (I can't go higher unless I give up padding the tank[:@]) the tank height would not be too bad and probably would not hurt anything BUT dammit If I'm gona butcher the cowl the damn tank height better be freaking perfect

I might have a heli header tank laying around... if I do I'll give it a try. I still think a pump or regulator will be my best bet.

John

Borrow a Dremel there JSN....you can do a nice job...I sense it.

If you can mount the motor in a sidewinder configuration...I believe you will have mitigated your problem.

Best of luck to ya buddy.

Just Git 'R Done.


'Race

Why don't you just mount it and see how it works before deciding it needs fixing? You can always add something later in which case I'd say the Iron Bay reg would be the best choice. If you are going that route can you move the tank back closer to the CG and really make it worth your while?

well Basin...we're trying to get this straight without resorting to gizmos that introduce a whole new set of variables into the equation.

A Cline reg is certainly an option, but so is a a bottle of sleeping pills and a fifth of Jack Daniels.

I guess JSN is the final authority here. I'm encouraging simplest approach possible. Gizmos as a last resort.

???

'Race

Race,

I have 3 Dremel's you can't work on planes or gun's for that matter with out at least one I could do the side mount and be done with it... I just might... the cowl has such a nice paint job and looks slick on the plane... I'd like to keep as much as possible.

BasinBum,

I Know If I mount the engine Inverted with the tank a full inch above the carb I'm going too at the very least have flooding/idle problems. The elevator servo would need to be relocated to get the tank on the CG... no biggie, even If I leave as is the tank could move back about 6 inches and butt up to the wing tube... that in it's self might make the Regulator worth it. Have you used the Iron bay? if so how do you like it? any draw backs you've found?

John

I'm with BB....run it and see. It may run slightly rich, but in that configuration
the only real problem you might have is flying inverted, and feeding in full down
control. In that case it might lean out....of course it depends.

Give it a chance and see if you really have a problem before you start losing sleep.

FBD.

I agree. Give it a shot and see.

If the plane D/S's and augers in.....it was FBD's idea right?

<GGGGG>

....nope, blame it on BB. [sm=bananahead.gif]

Hey guy''s I'm a big boy... I can auger um in just fine on my own[sm=lol.gif]

seriously though, I think I'll just side mount the engine and cut the cowl... I kinda hate to but...the more I think about it... screw it... it's just an ARF and ugly planes fly better any way



John

Hey guys...JSN is a smart man. He'll get this issue resolved and we'll all be impressed.

Let's move on to something else.

'Race

There are other ways.
I investigated [link=http://home.wanadoo.nl/pereivers/regulated_fuelsupply/fuel_problem.html]using the walbro pump and regulator combined with a glow carb[/link], in order to get freedom of tank placement, and consistent motor runs. It works extremely well.

John, the Cline and IronBay are, mount it and forget it options, I have an IronBay on my MDS 1.48 Diesel and a Cline on my Fox .74 Diesel. I'm going to run a Cline on my H9 Cessna with a Saito 2.20 inverted, I already tried it and the Cline supplies enough fuel to slow the 2.20 several hundred rpm when over richened. The IronBay requires an elbow when mounted on a Saito, the Cline comes with elbows that can face any direction. My theory is that no matter what brand it is an engine will succumb to some other malady long before the Cline or IronBay gives you trouble. Augering in, for example.

-------------------


That or buy a YS .45 or .63 for that plane and be done with it. <G>

I mounted a Saito 91 inverted on a Fliton 330 and everyone in a thread about it said it would be problematic. I was ready to order the Iron Bay but tried it first and it has run flawlesly. The tank is even moved back a bit and it draws fine and has a nice low idle. If it ain't broke.....

Also keep in mind that the center of the tank isn't what needs to be at the level of the carb, it's the clunk. Think of it as a siphon, it's the point where it picks up the fuel, not where it passes through the tank, that you are concerned about.

I am back to full time planes.
ALL, 1/2 A and up, get the Perry Pumps so I do not have to play with adjustments every weather change, or engine position.
It also lets you put any type of tank right over the CG or COB.
Use any brand of good pump WITH A REGULATOR you like but put one in.
Also, use a GOOD CLUNK tank.
---------With those items, it will start and run underwater. [sm=thumbup.gif][sm=thumbup.gif]

Cline regulator.

Are you aware the the Cline Regulator is to be no more than 1" away from the carb ?
Perry at least gives a 4"minimum. That lets me put their pump behind the firewall in the fuel tank area.
If need be, you can replace the short 4" crankcase with a 1" or 2" longer piece.
Capacity on big engines will be reduced a little.

Cyc, you're preaching to the choir here, the Cline is so much better than the Perry that they're not in the same league. The Cline will work farther than an inch, I've had mine hanging halfway between the cylinders of my Laser 1.80 V-Twin with no issues at all.