cpeisher

My Feedback: (13)

I have an old Made in Taiwan Royal engine, most likely in the 40-46 size range that was installed on an Avistar 40 trainer that was given to me. I've degummed the engine, but in the process i've lost one of the socket head cap screw head bolts.I've been to lowes to try and match it up with a nut, but they dont carry anything smaller than about M4 and this thread is pretty small and wouldn't fit in their test threads. Does anyone know what size these would most likely be and where i could get a 1, or 6, new ones?

fizzwater2

My Feedback: (61)

I'd say it's most likely a M3, uses a 2.5mm hex key.

Some hobby stores have M3 screws - you might find a set for something like a Thunder Tiger .40 or .46, Super Tigre, etc. I know my Thunder Tigers use M3 screws.

I bought a batch of them from rtl fasteners online, but I am not sure it's economical to buy a half dozen from them. With all the maintenance the race engines get, it's a good idea to keep spares on hand.

dant-RCU

My Feedback: (3)

I had a Royal .40 and .45 both. These engines were based on the old OS engines.

You will have better luck finding metric stuff at ACE hardware as I can pick up metric items when my
LHS is out of stock and I need some. I also keep a small plastic box that I throw just metric nuts and
bolts into just in case.

Might try ACE or perhaps a Tru Value.

Dan

cpeisher

My Feedback: (13)

i called Ace and they don't carry anything that small either. Tried a Hobby Lobby with no luck as well.  I'm calling RTL now to see if they may be able to help me select the proper size screw..

earlwb

Did you look in your local hobby shop at the RC helicopter and RC car parts sections? They have thousands of little metric screws and stuff of all sorts. They'll have the little screws for sure.
Worst case, is you get a longer screw and use a dremel cutoff wheel to cut off the excess and then use a file to smooth the end off a little.

Tower hobbies doing a "M3 screw" search:
http://www3.towerhobbies.com/cgi-bin...rew%3C%2Fb%3Es
and a M4 screw search:
http://www3.towerhobbies.com/cgi-bin...WS++&search=Go

spaceworm

I am pretty sure I have seen smaller than 4mm at TruValue. I had to replace the blade holder screws on a Blade CP and they were smaller than the "standard" metric hardware I have used. They had small metric nuts to fit also. Good luck.

cpeisher

My Feedback: (13)

well, the problem is that my local hobby shop is 1.5 hours away.  I need to start a hobby shop or something here...topic for another day.  On a good note, i found the other screw for the head.  so now all the fasteners are accounted for.   Now what i need is the manual for this engine that tells me where to set all the needle valves for the factory settings and break in.  There seems to be a low and high setting.  The needle valve i assume is still the high setting, and then there is a screw in the middle of the carb barrel on the opposite side from the needle.  If i remember correctly the needle valve is usually set two or three turns out from fully seated, then you slowly lean it in after break in and until you get correct throttle response.  I have no idea for the low end though...Any suggestions?

spaceworm

I stilll have the Royal .25 I bought new over 20 years ago. I have not used it much. I am sure I still have the orignal box with the instructions in it. It will not be until tomorrow that I can get to it, but I will scan the instructions and send them to you.

Regards,

SPACEWORM/Richard

spaceworm

Well, let's try this:

cpeisher

My Feedback: (13)

Wow, that's super helpful!!! Thanks so much.  It does say where to start the setting for the needle valve, and it also gives instructions for adjusting the idle setting.  I can probably make it work from there.  But do you have any suggestions on where to START the setting for the idle setting?

spaceworm

I will turn mine to closed counting the turns, and let you know. I don't think I ever adjusted the idle on mine so it should be factory set still.

Back to you soon.

Regards,

SPACEWORM

MILDBILL-RCU

My Feedback: (6)

cpeisher, if you open the throttle to full, you'll see the spray bar in the throat of the carb. The larger size tube of that spray bar is the low speed needle valve. The setting for a starting point would be to center the edge of the larger side in the carbs throat diameter. That will be a rich idle setting & should allow you to lean it out at idle 1/8 turns at a time till you get it were you want it. This should be set AFTER the high speed needle is set. If you remove the carb & look through the bottom, you'll see the main (smaller size) spray bar has the groove in it for fuel delivery. At full throttle, the fuel flow is controlled by the high speed needle in the center of that main (or smaller) section. When the throttle is brought to idle, the outer (larger size) tube starts moving to cover that groove to limit fuel at lower than full throttle settings. At idle, just a tiny bit of that groove is exposed to the air flow & that amount of exposure is controlled by the low speed needle (outer tube) by the small screw in the center of the rotating barrel on the throttle lever side of the carb. Set full throttle by leaning it to peak, then back off 200-400 rpms, then idle it down to set the low speed needle. Pinching the fuel line at idle will tell you what it needs as far as adjustment. If it raises in speed & runs for a few seconds better, then it is too rich. Turn low needle in a bit & retry, full throttle first, then return to idle. Pinch again to see what it needs. When set properly, you should get just a breif raise then start to slow down. A rich idle could run with a pinched line for 8-10 seconds or more to use up the extra fuel that it is getting. A lean idle setting will die out just about instantly when pinched. You are looking to get maybe 1-2 seconds of run time with just a hint of speed increase with your low speed setting before it starts to decrease speed while pinched. All this is really simple to do & is all with the asumtion that fuel lines, clunk, tank & its height are all ok. Hope this helps, Good luck with it. Bill

Iflyglow

My Feedback: (79)

I had a friend with a Royal .46 like 18-20 years ago, and it was a very strong engine in its day.

mteverest

Which glow plugs work well with the Royal 45?

cheers

brent

cpeisher

My Feedback: (13)

Well, i have great news!!!

First here's the whole story on this engine It had not been run in at least 10 years.  My buddy gave me the plane, with engine and Futaba 4NBF radio of the top dusty shelf in his car shop.   The wild thing is that this model, the Hobbico Avistar 40 (the original) was the EXACT model i had when i first got into RC glow planes!!!.  Exact same radio too!. 

When i got it the engine it was completely gummed up from the 2-3 oz of fuel left in the tank, all the way to the muffler.  To de-gum the engine i attempted to put it in a crockpot full of anti-freeze overnight.  I later discovered that the "anti-freeze" jug i used was actually just water!!!  So i basically boiled the engine in water for over 12 hours.  Outstanding you say?!?!

Following that i took the entire engine apart, cleaned and polished EVERY single piece.  I even had to wire brush the rust out of the sockets in the head bolts.  I put it all back together with a generous coating of WD-40 over everything.  I had to trace and cut gaskets from copy paper for the front and rear crankcase joints, and USPS Priority mail envelopes for the exhaust joint.  I took the plane to the local field today, and they sell fuel BTW.  I got a gallon of 15% and had a couple of guys look over everything.  Once we got the spinner and prop on and secure, we took it over to a test stand and would you believe this engine fired right up on the first turn with a glow starter attached?!!!!!  I mean the guy just barely bumped the starter and it was running.  Now it was running very rich at first, but it was running.  We immediately leaned the mixture to get a good RPM at MAX and then started checking it at idle.  We didn't do any idle adjustments, but tomorrow we'll get it dialed in and I'm going to put a NEW maiden flight on this "cut the nostalgia with a knife" RC Airplane.

 I was stunned.  It's not a testament to my skill at all, but this great community of people here who helped me get a similar manual for this engine, helped me figure out how to clean it to begin with, and a great couple of guys at the local field who helped me get it tuned up and running.  Thanks everyone!!!


Chris

dennis

My Feedback: (90)

Many of the Royal(Leo) engines were direct copies of OS designe. By that i mean everything was interchangeable in them. Including the screws.
Dennis

cpeisher

My Feedback: (13)

Well i took the plane out to the field and tried to get the engine tuned up. It didn't work out very well. i spent nearly an hour fooling around with the thing, going through several different glow plugs and fooling with the needle adjustments, both low and high end. i think i need to so some more research on the full correct procedure, with step by step instructions on how to break in, and tune an engine, from start to finish. Is there something like that out there in cyberspace that includes troubleshootingsteps? When i mean troubleshooting, i'm primarily concerned with "When i do X, Y happens, so this means Z and W is how you fix it..." For instance, the engine runs good at half throttle, but skips when i move the throttle up..." or "it runs fine at idle when i have the glow starter attached, but when i remove it it sounds too rich and slows down and quits..." Can anyone recommend and good link? And does anyone have a recommendation for which glow plugs work best with this engine? Personally, i would rather have a glow plug that lasted a LOOOOONG time, than one that allowed me to squeeze every last drop of performance out of this engine. What would be the longest lasting glow plugs i could use in this engine?

Thanks again!

cpeisher

My Feedback: (13)

here are some links i've found so far...hopefully, someone can tell me if any of these are worth looking at or following...

http://www.rc-airplane-advisor.com/t...ne-engine.html
http://www.rc-airplane-advisor.com/m...ne-tuning.html
http://www.*********.org/cars_eng-tuning.htm


Thanks, and again, all the help is greatly appreciated...

cpeisher

My Feedback: (13)

here are several pages from the OS manual for the 46 AX...

spaceworm

HERE is a good one for Gas engines: http://indianatinygasengines.com/page.aspx

cpeisher

My Feedback: (13)

Well two days ago i set up a little test stand in my garage and fired up the engine. I spent about an hour slowly dialing in the high end needle and the low end needle, and went through two tanks of fuel.

I did start by setting the low end needle to about the center point of the carb throat. I did the high end needle first. Slowly turning it in until i got maxRPM and then back off 2-4 clicks. I usually waited 10-15 seconds between adjustments to make sure that it had time to adjust and manifest whatever effects it was going to produce. I ended up about 1.25 to 1.5 turns out from fully seated. Ithen started messing with the low end.

I took the throttle down and let it sit for a little while.Then Imade adjustments on the low end in 1/8 turn increments until i got what i considered to be a good pinch test result. Again i waited about 10-15 seconds between adjust ments. If i could pinch and get 4-5 seconds of slowly increasing RPM, then a sharp drop off in RPM as the engine began to cut off, then that was what i was trying to achieve.

Once i had it more or less successfully tuned using that method, i would spent 30 seconds to a minute at idle, then throw it wide open, to further test the low end needle. I needed to lean out the low end a little more to keep it from boggin down when i threw the throttle wide open. I got it dialed in pretty good i think. It's still not a perfect transition from idle to full throttle if it's been at idle for more than 30 seconds. It doesn't bog, per se, but you can tell that the low end is still a little rich because it's maybe a second or too longer than it should be. I'm not sure if i want to keep it running a little rich on the low end or not.I hate buying glow plugs,andIseem to remember that having the high end mixture a little rich will help the glow plugs last a long time, im not sure if the low end helps with that or not. So right now, 3 clicks off max would be 200-400 rpm less than max RPM, so i have it 1-2 clicks more rich to help with break-in and long plug life. If i need to adjust this please let me know.

I talked to my buddywho gave me the plane to begin with, and he said they only flew the plane 5-6 times, so it's probably still technically in the "break-in" period. So, unless anyonehas advice to the contrary, i think that i'll be better off for a few tanks running it a little rich on the high end. Should i keep it a tad rich on the low end as well, even if it means not having a perfectly smooth transition with a snap from idle to max?

fizzwater2

My Feedback: (61)

I'd be inclined to open the high end needle just a bit more to fly it. 200 down from peak is likely to be on the lean side in the air, as the propeller unloads some. I'd probably go 500 down from peak at least.

MrGreenSpeed

I agree 400 to 500 rpms from peak, with plane level.

Go fly 3 or 4 tanks doing big loops at full throttle, this will help finish the break in, as on the up side the engine leans and heats up and on the down side it richens and cools.

If at any time You hear the engine sag on the up side, land and richen the high speed a click more.
I also add castor oil to have %20 oil minimum during break in.
Jeff

cpeisher

My Feedback: (13)

Ok, well i'll follow both or your advice and richen it up and do some big loops to help it break in. Hopefully i will get out to the field tomorrow, if not, then Sunday. maybe i'll post a few pictures and a video or two.

MrGreenSpeed

Cool, hope every thing go's good for You.
Eagerly awaiting some pics and a video.
Jeff[8D]