Will reeds stick..

I know.. maybe I will. Believe me.. I thought about it when I saw the sunshine this morning!

The reeds that clip in are probably more prone to sticking. The plastic retainer allows the reed to float.

I'm with Kim and Rusty, you bench tested it. Now go fly it!

Ron

I recently disassembled a white plastic horseshoe backplate engine, that had  "passed" the blow/suck test. Upon inspection it was/is my first experience with the crystal clear plastic reed valve. The bottom of the reed was stuck in some old soft goo (castor) and the top was clean and free to move back and forth. I removed the retainer and reed, gently cleaned all surfaces and reassembled. Still passed the suck/blow test and now the reed was free to move around with the help of a toothpick.  So in my experience. Yes reeds will stick.

No clue. Ive had good luck with one engine and bad luck with the next. No rhyme or reason it would seem.

Yes, good weather should be used. I'm hoping to fly something today too.

Phil

Thanks for the replies guys.. I really appreciate it. There won't be any flying today.. but I've got the airplane outside testing my homemade muffler with a pressure-line attached. There's been some recent blood (sorry I didn't take a photo) but I just got bit by the Cox black 2-blade 5 x 3 that I put on.

I really should take the engine apart.. because the runs are unsteady, even with open vents. I think that the pressure-line has some merit though. I had one run that seemed to smooth-out when the pressure line was connected and another short-line to the "top" vent on the wedge was pinched-off. I'm running pressure to the bottom vent.. because it's opening inside the tank is at the top. Maybe it makes no difference.. but I was concerned about introducing air-bubbles into the fuel (while sitting there on the table at least...) I figure that when "flying"; both vents should be clear of the fuel after a few laps.

I'm running Sig "25" with a new Cox head and 2 head-gaskets. I keep opening the needle and can't seem to get a rich burn. If I open it any more.. I'm afraid it's going to fall out. It's probably gummed up inside. I did connect my fuel bulb directly to the feed-line and squeezed some air through.. hoping it might improve things which it did somewhat. I'm on my way outside to try again.. now that the bleeding has stopped..

Oops, that's gonna leave a scar! Call the AMA ( American medical Assoc) for band aids and stitches. When that happens to me, I always think of Mott the Hooples, Once bit, Twice shy. I never have had to, but have heard you can use "superglue" to hold skin together on shallow cuts.

That is a neat looking aeroplane Roddie.

Reeds do stick but it is quite rare. Not so much sticking but castor goo will stop them working properly and a good clean with the infamous Hoppes No 9 will fix that.

I have had my fingers, thumbs, hands and legs bitten by propellers more times than I can remember. I have used "Superglue" to stitch a cut back together but don't recommend it. It is hard to pinch the cut together and apply the glue. It bloody hurts when you get the "Superglue" inside the cut!

ian1954 wrote:I have used "Superglue" to stitch a cut back together but don't recommend it. It is hard to pinch the cut together and apply the glue. It bloody hurts when you get the "Superglue" inside the cut!

Never caused by a prop (yet) but I've used CA many times to hold a cut together. It stings a little, but they do use a similar product professionally, so I figure it's probably safe. It always seems to happen to the tip of a bass playing finger just before a gig. While it may numb the finger tip a little, it's pretty durable if you manage to get the cut dry and add the glue when it's not bleeding. Because it usually happens to me when fixing cars, it's also a good way of sealing out the grease & crud.

Marleysky wrote:Oops, that's gonna leave a scar!  Call the AMA ( American medical Assoc) for band aids and stitches.  When that happens to me, I always think of Mott the Hooples, Once bit, Twice shy.  I never have had to, but have heard you can use "superglue" to hold skin together on shallow cuts.

 It wasn't that bad.. I basically needed to walk away and report/document my lack of success through that last post.

My luck was no better when I went back out.. but I wanted to at least hold an airplane in my hands and burn some fuel in honor of fellow C/L modeler Dave Cook.. who's wake was today.

This airplane was last run/flown with a #2 Perfect short wedge tank (approx. 10cc's) The tank had been soaking in a jar of solvent along with several others.. and flushed multiple times over the course of months using a fuel-bulb. I flushed it again today after removing it and the engine from the airplane. All tubes were clear.




Today's runs were with the muffler and "one" full-flow pipe installed. The engine ran very strong.. but wouldn't stay running for more than around 15 seconds. It was drawing fuel.. but there's something wrong with the flow. It has a slit-exhaust type cylinder with no SPI. I'd ran this muffler-design plenty of times with no problems on other reedies.. so I don't think that was the problem. I'll have to disassemble check and clean everything and re-run it on the airplane.. open-face, to establish a baseline.

This airplane was an experiment..   back in the early 90's to build as close-to a symmetrical airframe as possible. If not for the landing gear, it would be. It has twin vertical disk-rudders at the tips of the stab that are slightly offset. The wing is approx. 132 squares (5.5" chord x 24" span) The wing and fuse are flat built-up frames of balsa and spruce with 1/32" ply nose doublers that extend back 1.5" behind the spruce L/E. Less-engine it weighs just over 5oz. There's probably close to an ounce of weight alone in the gear, pushrod, lead-out guide-rail and tip-weight.




When I finally fly something.. it'll probably be this model.

Roddie,

I first thought the erratic run was caused by the muffler on an SPI cylinder, but read later it is a non-SPI. So other than the reed stuck to the plastic backplate (that I never experienced) I would think of some unwanted air intrusion either at the NV threads - that I know you also remedy with a silicon tube pulled on the NV and the spraybar threaded end, - or through the crank front end (in case the radial play of the shaft is too big) But I am sure you also have checked these out.

Maybe the fuel line is clogged..this is seen when the engine does not react too much to the NV setting.

Are you sure the tank vents well? A 15 seconds strong run then a sudden stop can also be caused by depression in the tank if venting is blocked.
Sorry for the too obvious guesses.

Continuing on as Captain Obvious, did you replace the glow plug? Sorry if I missed if you said so.

balogh wrote:Roddie,

I first thought the erratic run was caused by the muffler on an SPI cylinder, but read later it is a non-SPI. So other than the reed stuck to the plastic backplate (that I never experienced) I would think of some unwanted air intrusion either at the NV threads - that I know you also remedy with a silicon tube pulled on the NV and the spraybar threaded end, - or through the crank front end (in case the radial play of the shaft is too big) But I am sure you also have checked these out.

Maybe the fuel line is clogged..this is seen when the engine does not react too much to the NV setting.

Are you sure the tank vents well? A 15 seconds strong run then a sudden stop can also be caused by depression in the tank if venting is blocked.
Sorry for the too obvious guesses.

edit: Hi Rusty, yes... a new glow-plug had been installed on the last run in 2012. Actually... I tried something I've "never" done.. and that's installing more than one head-gasket. I installed two for Sunday's runs. The engine ran very strong.. albeit intermittently.

Hi Andras.. and thanks for checking in! The engine had not ran since 2012.. and had not been taken off the airplane since then. I did remove the needle while it was on the model and forced fuel through until it squirted out. The needle itself looked clean.. but this engine had not received the "needle-seal" treatment that I have since learned here on the forum. The engine is off the model now.. and waiting to be taken apart for inspection. There is no excessive play in the crank.

The external wedge tank had been flushed and all tubes were clear. I will examine the reed and retainer. Who knows.. maybe it's bound-up somehow.. The blow/suck method of testing will be done.. but I'll try to pay close attention to the retaining system. I actually can't remember if it's the early circlip type.. or the cap-style retainer. I'll find out when I take the little mill apart!  If the latter; I'll check the flange for cracks and replace it if any are found. I'm skeptical as to it's sealing the case with a gasket.. as compared to a "tank-back" engine. I think that the horseshoe back-plate's screws need just as much attention to torqueing correctly as the tank-back engine's. You know how reedies are... everything tight and sealed makes them run their best.. right? They draw fuel wonderfully by nature.. I believe that fitting a larger fuel line using compression-fittings at the NVA and a large feed-line tube-size off the tank helps to feed a thirsty one with a hypo-ported cylinder too.. but that's not the issue with this engine.

My flipping-finger was bleeding today at work.. That Cox black 5" x 3" two-blade was brand-new. I peeled the stickers off yesterday afternoon.. and used "Goo-Gone" solvent to remove the adhesive residue. I knocked it (my f*#*#ing-finger..) on anything that was in the way of what I was doing.   .. Went through three "Band-Aid" changes before I found some "cloth" bandages with decent adhesive that would hold.. (I had to double-wrap of course..) I digress...

A large part of my Cox engine testing as of recent; is to see how and "if" my muffler design can enhance/improve the performance/function of the Cox .049 engine overall. By "performance" I mean in one aspect; whether it can be tapped for pressure. Muffler-pressure is nothing new.. but it's "not" something normally applied to engines under .10 cu. in. If running an SPI cylinder; will "too much" back-pressure augment the benefit? My muffler-design has the capability of running multiple pipes having differing orifices. Might this offer a cross-scavenging effect? What's the best method for connection to the tank-vents for easy fueling/starting/running? When it comes to "function"... my muffler does cut noise as compared to running an open-face exhaust-port. Yesterday's test was conducted with a muffler designed for dual-pipes.. but I blocked-off one side.. and ran one full-flow pipe and a smaller pressure-fitting/line which was connected to the wedge-tank intermittently during the tests. The engine cylinder was oriented "inboard" (in a C/L configuration..) and the muffler was installed with it's single-pipe facing down and rearward with the smaller pressure-line to the tank above it. I could ramble-on forever.. because this is my thread.   but...... I must say; that the only oil on my airplane was under the inboard wing, due to the single-pipe being directed that way. Standard plastic drinking-straws fit tightly around the .22cal. shell-casing "pipes" that I use.. so if you ran one down a landing-gear leg.. or extended a "header-pipe" out a bit.. you'd be wiping a LOT less oil off your airplane. When Cox designed mufflers for their engines.. it was kind of an "all or nothing" effect. Most users found them to be too restrictive to power. Some people may have tried drilling them out.. but they were stuck with what they'd achieved.. as well as there being only one outlet for the exhaust. Our member "1/2Anut" has done quite a bit of experimenting with tuned-pipes on his Cox engines.. so there's a lot more to exhaust-tuning than one would expect.