Hey Joe,

So you are pressurizing your tank with crankcase pressure instead of muffler pressure?

Mike

Yep, and is seems to work really well. I haven't tried it without the check valve yet, but with it, there's no problem building up tank pressure! The only down side I've seen so far is that you MUST release the pressure on the tank after a flight or you'll be leaking fuel all over the place. With the regulator inline, there's something to stop the fuel from being forced into the carb, but without it, there's a slow seepage though the needle valve into the carb.

I theorized that after running the engine for a while, pressure would build up too much in the tank and make the engine run richer, but so far, I haven't seen that happen. But, as I said earlier, I haven't flown it for very long this way, so it could still happen.

That fitting in your pic is the part I'v already ordered (on b/o) from Tower. It sure does look like that shouldered hole is meant for a pressure fitting, though.

And since you've got to drill a hole (whether in the top left bolt hole or in this shouldered area), I'm not sure one IS better than the other. Unless there is a pressure or lack of pressure argument.

I've even had a guy at out field that said you can drill a hold through the mounting flanges on the engine between the two holes and get the same pressure.

Later.

The Perry instructions recommend drilling through the mounting flange as an option. If I were using a regular pressure nipple, I would just drill through a flat area on the backplate and make sure it doesn't stick out into the crankcase.

Tripacer, you got it!

Joebob, if the engine runs fine with just a check valve for a couple minutes, then it probably will be fine, 'cept for the fuel spewing out when you shut down. I think rich runs are inevitable though.

FYI,

I pulled my engine off. The shouldered hole in Jim's pic above is too big for a spare pressure nipple I had laying around.

I was hoping I would be able to just tap some threads, drill a hole in the plate and done. Oh well. I'll be watching the mail for my Tower order.

Mike

Hi Mike
I ordered the pressure fitting from Tower the other day and received shipping notice today.... The fitting was in stock so I hope you've got yours by now.

You told me you wouldn't mind posting pictures..... So here is my request.
1: Side shot of the tail section showing where your pull-pull cables enter the fuselage
2: Side shot of the cowling. Mine has so much down thrust that the side trim won't match when the spinner is centered? Because I have to tilt the cowl DOWN!

3: When you installed the landing gear did you have tow-in or tow-out. With the main gear installed (slanting forward) I've got a good bit of tow-out. Just curious!

I've got the Bisson Pitts muffler and it looks like I won't have much of a cowl left on the bottom side ;O(

BTW: I'm really interested in running just crankcase pressure without the pump as mentioned in one of the other posts.

Thanks
Jim

I'd say your engine is mounted too low. Mine is mounted on it's side and the mount is about 1/8" from the top of the motor box. My cowl lines up about perfect. Also using a jtec muffler. Had to cut a hole for the corner of the muffler on the head side. If I got a Slimline it probably would have fit inside the cowl.

Mike:
I have been reading this thread for a couple of weeks and I want to put in my 2 cents. I have the Creek Staduacher and have a Moki 1.8 on it with a 24 oz fuel tank mounted at the CG. My engine was responing like yours (no response after 2 turns out on the needle) I put a pump on it and it didn't help. The engine would peak out at 2 turns and never lose RPM no matter how far out the needle was turned. The problem was the fuel tubing supplied with the tank is the same size as a 10 OZ tank. I bought the next size up brass tubing and a larger clunk and installed large tubing from the carb to the clunk. The problem is that only so much fuel will travel through that small tubing no matter how much you push it (or pull it). It's basic hydraulics. With your tank mounted at the firewall you should not need anything but muffler pressure.
If the pump doesn't work you might give it a try. I think the larger tube should be used on anthing larger that a .90 size engine.
Maybe only 1.5 cents worth, but to you it is free.
Hal Lockett

Jim,

I just got the notice today that my pressure fitting is being shipped. I can't remember if you've been in the "Tachometer" posts about the 1.60. If not, check it out and see what I did with that other shouldered hole.

I'm also curious about running crankcase pressure.... or what about both? Muffler and Crankcase?

FYI, I installed the pump the other day and will hopefully test it tomorrow.

Hal,

Thanks for the insight. I have already installed the large fuel tube and stopper assy, which comes with a bigger clunk and bigger tubing.

As I was going to move my tank to the CG (but it was going to be too much work undoing what I've already done), I put it back and noticed something. I had the tank (a slanted sullivan) surrounded by foam. It is possible that the hoses were being smashed by the foam at the front of the tank. Just a slight possibility, but I re-did my tank install a little better..... hopefully.

I pretty convinced that the muffler is causing all my problems. If you look at how much restriction is in a stock muffler, it would make sense that there would be more muffler pressure because of it. Just the fact that the stock muffler has 1/4 of the outlet of the Slimline, PLUS it has a baffle in it.

Anyway, all this is speculation. I've got a stock muffler coming in the mail thanks to RCU! So if this pump doesn't work (I think I'm pretty safe there, though), I will be able to test my stock muffler theory.

OH! Jim, I'll go take some pictures right now. I would recommend cutting open the bottom covering to see where your pull-pull wires are going. I think there is a frame brace that my kevlar might be rubbing against. I've got to check it out. Also, my cowl is not perfect either. I'm really not bothered by it, so your engine may be ok. My landing gear seems pretty straight to me, but honestly, I may not have noticed. I'll check it out.

Thanks for the interest and keeping this thread going.

Mike

Jim,

Here's a pic of the pull-pull exit.

Here is a pic of the mounted engine. Check this with yours and see if that is why your cowl doesn't match.

Sorry, my cowl is not on as I'm going to be testing this pump tomorrow, so I left it off.

Mike

I did a little more experimenting with the pressure/no pump/reg setup on my 1.60 today. THe engine still runs fine. The only problem I've seen so far is that it tends to leak fuel a lot. Presumably because of the tank pressure forcing fuel past the needle valve and into the carb all the time, not just when running. I release the pressure as soon as I kill the engine, but you can get enough pressure to make it leak by simply turning the prop over.

Seems like I get a fairly consistent run on the engine the entire tank, though. Idle was 1600-1800, top end set at 8100 for flight.

But, I think I'll be putting the Cline regulator back on, if only for the leaky fuel problem. I only took it off because it was tough to get the 1.60 to take throttle on the first crank of the day.

Mike, looks like your engine is mounted low. I got a Slimeline today and it fits inside the cowl. Too bad I already cut a hole for the Jtec.

Started to break my engine in today with the pump and it is slobbery rich at 2 1/2 turns out. Tank is on the CG. These engines don't need the large tubing, their fuel consumption is about the same as a .91. 16 oz tank should be fine.

Ran mine with the pump today. MUCH better, but I still need to get the needles set right. It was a little rough during transitions. At least it kept running this time.

Till next weekend...

anyone having problems with your landing gear? I was just taxiing mine around yesterday , frist I noticed that one of the wheel paints had busted. When I picked it up I found that the glass gear had cracked across the bolt holes. I can't blame this on a bad landing as the plane hasn't left the ground yet. J ust wondering if anyone else is having a problem.

I flew mine for the first time yesterday. Mine was extremely tail heavy at the 30 percent or 4.98" CG location. I was lucky to get it back on the ground. I had to land it hot in order to keep it from tip stalling, and just breathing on the elevator made it snap. Do not believe the elevator throws on the instructions. I landed so hot that I knocked off the landing gear. I mounted the servos as instructed, three in the tail. I installed the tank over the c.g and the receiver and battery are in the nose at the firewall. I have a YS 140L on it for power. With this set up and with a not so light motor, I still have to add 1 pound 12 oz of weight to balance at 4.5 inches. I am extremely disappointed with this weight. I am going to move the rudder servo up and use a pull, pull. This will help, but I do not think it will help to the extent I would like. Does anyone know how this bird can come in at 10 1/2 pounds the low end of the advertised weight?

t309,

I have not had any problems with my landing gear, although my wheel pants are mounted a little too high.... or the wheels are too high in the pants. The wheel pants are very close to the ground and this weekend, they caught a weed and stopped the plane on a slow landing. It ended up slowly tipping over on it's nose and then landing on it's rudder. Field repair and it's ok now.

Remcl,

The only way I've hear people can get the weight AND balance correct, is to mount all the servos in the center of the fus'. I have my rudder there, and still had to add 8+oz's of weight to the nose.

Good job getting your plane in! Mine landed in a tree the first flight.

Mike

I have a MVVS 1.6 Gas engine in mine with servos in the tail. I have 2 x 1200mah rx packs just behing the wing tube and 1 x 1600mah ignition pack on the side of the motor box. My CG is right at 5" from the leading edge of the root and seems to be about perfect for my flying style. My engine with the ignition, battery, and muffler is right at 41oz. I think the OS 1.6 is about 33oz without the muffler. That only makes a difference of about 5 oz between the two, yet some of you are having to add over a pound of lead???? There may be alot of variation in the wood quality in these things. I guess you get what you pay for.

Mark

has any 1 acheived balance w/out lead using a glow motor? I am putting some finishing touches on my SS from Da funtana and need to get back to work on this beast. what kind of weigh for those flying did u acheive?
sounds like i may need to go ahead and put that smoke system on this one otherwise.

I've got 2 Hobbico CS65s in the tail, a Hitec 645MG in the wing area for rudder, 1600ma NiMh pack mounted on the engine box, OS 1.60 w/ Brisson pitts muffler, Tru-Turn 3.5" spinner and a Pro Zinger 18x6 prop.

Added 12 oz of weight to the bottom of the engine box. I may be a little nose heavy now, but I wanted to play it safe.

BTW, this is on a Creek Staudacher. Pretty close to the same configuration as the Extra...

I also have the Creek Staudacher ( I have the Extra in the box that is why I'm following this thread) with a Moki 1.8,Bisson Pitts muffler,TruTurn 3.5 spinner, 18X10 wood prop, 6 volt 1650 ma NiMH pack mounted at the firewall, a 24 oz Dubro tank at CG and it balances at 4.850" from the leading edge with no added weight. Haven't flown it yet but I'm hoping it will be ok (my first large scale).
Hal

I have the OS 160 with slimline pitts, 2 225's in the tail, 945mg in the bay, and 6v nimh in the engine box. No added weight and cg is at 4.75"
Aft CG means pitch sensitive, not unflyable. Decrease the elevator throws. Remcl, don't think that will cure your prob though, your wing loading is probably too high to be stable with an aft CG.

Hi Tom (h82crash)
I was glad to read your last post as this is also what I'm going to do with my Extra. You said you had your battery "in the engine box" Did you mean "on" the engine box? If not how did you access the engine box?

Also I've go so much down in the engine that I'll have to mount my Cowl tilted slightly down to keep the Spinner centered on it.
This keeps the trim on the cowl from being horizontal to the trim on the fuselage. I thought I may have mounted my engine too low but my lines look just like in this foto.

Also I would like to know "How far your cowl overlaps the fuselage?"

Jim

Hey Jim,

I'm going to have to check my engine box. I don't remember it having downthrust. Maybe it did and I didn't notice (not really that far fetched), but I'll let you know. And my cowl overlaps by about 1/2" or so.

Mike

Thanks Mike

Ignore the "how did you access the engine box" in my previous reply.... I really should finish my first cup of coffee before I start posting replys

I'd have to move my engine back 1/2" to get the cowl to overlap a half inch.

I'm putting 2 hitec 225's in the tail for the elivator. If I have to put more than 8oz to make it balance I'll move them foward. I REALLY HATE to add weight

BTW I've removed all the covering from the bottom of the fuselage per your suggestion. Also thanks for the pictures I requested!