I am new to four strokes.

[Clancy Arnold]

Guidance please!
I bought a kit and engine for a new CL Sport Scale model.  The Model was designed for RC but I will build it for CL.  I plan on using 70 ft .027 lines and my U/Tronics control system.

The model is Nick Ziroli's WWI Taube.  88 inch WS and 1500 sq. inch wing area.

I bought an OS 91 Surpass pumped engine to power it.  First question what kind of test stand should I use to run in the engine?
Clancy

[john e. holliday]

Clancy, remember to forget every thing you know about 2 strokes.  If instructions came with the engine read them thoroughly.  I have  a .70 four stroke that is slated to go in a fun scale plane.  I bought one of the ready made mounts and boltd it to a peice of 2X4.  It is clamped to a saw horse.  It is amazing how much power these 4S's have with the low rpm.  Guess it must be the higher pitch in the props or could be the diameter which is larger.  Hae a good strong starter or do like I do.  Turn it backwards until you feel compression.  Pull forward a bit and then smack it hard backwards.  Sometimes when I feel a kick I go ahead and flip the prop.  Do use a heavy glove until you are used to it.   

[Clancy Arnold]

Thanks Doc
I read the instructions:
Spin the engine with a starter and slowly open the throttle until it starts.  Sounds easy!(?)

The instructions call for a 15 x 6 or 16 x 6 wood prop.  I asked for a 16 x 6 prop but the salesman at the RC Hobby Shop sold me a 15 x 6 that I did not catch until I drove 20 miles back home.  So that is what I will use first.

I have some metal motor mounts that I could drill for the OS 91 FS to mount on.  They are cut from 1/4 inch aluminum plate.  I will mount them on a BIG board to support the engine and hopefully it will stay in one place. LOL  I originally had them for the HP 40's in my C-7A Caribou.



Clancy

[john e. holliday]

Make sure what ever you anchor it too will stay put.  First time I fired the .70 I had to sit on the saw horse.   

[proparc]

Make sure what ever you anchor it too will stay put.  First time I fired the .70 I had to sit on the saw horse.   

Yes, anchor the engine VERY firmly. 4 strokes are very strong. Mine started to pull my test stand over, but I was able to catch it and anchor it with 2 extra masonry blocks. Big difference between an ST 46 and a Saito 72!!

[Clancy Arnold]

I normally test run engines under the tree in the front yard.  It has a 10 inch dia. trunk that I will tie the stand to.  That might hold it! LOL

Thanks,
Clancy

[john e. holliday]

Now don't blame us when the tree comes up by the roots. LL~I have a cast iron vise I clamp to my saw horse and the 70 with a 13 inch prop was pulling the saw horse. @

[Paul Wood]

Clancy,

Please, please don't stand in front of the engine while it's running.  Four strokes often kick back, especially when new, and will throw a prop completely off the prop shaft.  This can also happen when you're starting it, but at least the engine isn't running.  Until the engine is broken in, the valves seated and the carb adjusted, be careful!  I've seen some very close calls, including myself, at the R/C field.  Also, be aware that the larger mass vibration can loosen anything in you're mounting rig that's not secure (i.e. C-clamps).  Have fun, they are great engines, but very strong.

Paul

[Clancy Arnold]

Thanks Paul
I normally try to set a new record in getting BEHIND an engine when it is running in a test stand.

I hope that 91 4stroke puts out a lot of power because of the size of the model and the amount of air drag all of those bracing wires will create.  I bought a 15 x 6 wood prop to try it with.  They could have made two 10 x 6 props out of the wood in this one prop.
Clancy

[john e. holliday]

If there is enough threads, go to your local hardware and pick up a nut that has the nylon insert.  Did that both of my 4S.  If the propcame loose it stayed with the engine.   

[Clancy Arnold]

Doc
Thanks for the suggestion.  I think I have some 1/4 28 nylok nuts in stock.  The engine came with a double nut system that looks like it would be hard to loosen.  The second nut goes into a tapered hole in the first nut and is castelated to compress onto the threaded shaft.

Clancy

[john e. holliday]

You sure that is not a 5/16th shaft on that big engine?

[Clancy Arnold]

Doc
You are right!!
I should have remembered since I just bought a prop reamer to make the new prop fit the shaft.  Now I will have to take the current prop nut to a hardware store and match the threads.

I ordered a new set of the biggest motor mounts SIG sells to use to mount the engine to the test stand and later to the model. 
Clancy

[john e. holliday]

I usually take the whole engine to the hardware store when looking for screws and nuts.  You should see the looks I get when I tell them I needed parts.

[Bob Reeves]

Forget the nylon lock nut or any lock nut except the ones that came with the engine. You won't be able to turn it as you have no way to hold the shaft. All the stock nuts take is two wrenches.

[Clancy Arnold]

Doc
I will take the engine with me and see how they react.  LOL


Bob
I can handle two wrenches but the wrench supplied has the correct sizes on opposite ends.  A standard double ended open end wrench.  I will use some of my 50 year old Craftsman wrenches for the first time.  Oops, I need to buy new METRIC 12 and 14 mm wrenches.

Clancy

[proparc]

Now that I think about, you can hit up Han Xing Ping for 4 stroke info-in fact, you can hit up the whole Chinese team!!!

[Tags:]

Jump to: Please select a destination: ----------------------------- Announcements ----------------------------- => Stunt Hangar Admin announcements ----------------------------- General control line discussion ----------------------------- => Open Forum => The Suggestion Box ----------------------------- Find One Teach One ----------------------------- => FOTO op Members in your area that are willing to teach control line. ----------------------------- Engine basics ----------------------------- => Four strokes only ----------------------------- Design ----------------------------- => Engineering board ----------------------------- Nostalgia 30 ----------------------------- => Nostalgia 30 ----------------------------- Vendors Corner ----------------------------- => Action Hobbies/Lazer Works => Aero Products => builtrightflyright.com => Northcoast Hobby => BJM Enterprises => Control Line Central => Control Line World => Core House => Cox International => Custom Cut Kits => Eliminator Props => Frank Bowman Rings => LEE MACHINE SHOP => Minnesotamodeler => S&S Hobby => U/Tronics Control => Windancer Models ----------------------------- Local Clubs ----------------------------- => Post your club info here