MarvinE255

My Feedback: (10)

I have this engine in a world models mustang using a pitts muffler(slimline). I tried a 12x6 prop and the rpm was poor. Went to 11x7 and got 12,000. I have not tried a 10x7 but think it will work better. I think the pitts is somewhat restrictive on the exhaust. I was using 15% omega fuel and APC props. Doc

AstroDad

Will this engine run well on 5% nitro?

Mr. Mugen

I ran mine with a 11x7.5 on my 40 size sukhoi and dont care for it. I wrote down the rpm....but lost it. I will recheck before changing it. I think a 10x8 is next.

DarZeelon

Quote:

ORIGINAL: AstroDad

Will this engine run well on 5% nitro?

Yes, AstroDad.

It will even run pretty well on FAI fuel (20/80 castor/methanol).

Power will be down ~150-300 RPM at the very top (compared to 15% nitro) and fuel-consumption will also become noticeably lower.


You can remove the head shim (replace with one fabricated from thin aluminium foil for a seal), to get some performance...

AstroDad

I have this engine on my Arrow 40 trainer and love the power. It climbs like crazy, and also does not go so fast that I worry about the airframe failing.

In this thread I see a lot of discussion about props smaller than what is recomended in the manual. Are you guys using the smaller props just to improve top speed performance?

for my trainer I have been using a 12X7 and do not really want any more top speed, but if possible, I would be happy to improve my flight time, by cruising around longer while burning less fuel. Should I consider a different size prop? I have not tried 5% nitro, so I suppose that would be my next step, would 0% be even better?

DarZeelon

AstroDad,


A 12x7 prop is HUGE for this engine.

Using a 12x6 will free more RPM from the engine, but actual flight speed will be reduced still.


Additional speed management can be done by managing the throttle...

Your trainer will easily fly at 1/3 throttle... It will even climb at this setting.


Your engine will idle more reliably on 5% nitro than on 0%, but make sure the fuel you use contains a good measure of castor oil.
[link=http://osengines.com/faq/product-faq.html#q2]This is[/link] what OS have to say about it (ABL engines are also ABN).

Don't use Cool Power green, which is all synthetic, for example. Don't care what others do (they will eventually pay for this 'violation', with internal failures).

jeffk464

I switched from a 12x7 to a 12x6 and didn't really notice a big difference. My rpm jumped 500rpm or so, but a 12x6 need to turn faster then a 12x7 to pull the same rpm. I think its a toss up, but the engine runs fine on either prop.

Marvin - This engine is designed to spin a larger prop at a lower rpm like a 4 stroke, there is no real need to try to up the rpm.

jeffie8696

I would love to see the tach numbers posted in the tachometer readings section. http://www.rcuniverse.com/forum/tt.asp?forumid=173

liquid_TR

I dont think so.. Im was running mine with APC 9x9 at 15200 rpm... singing quiet happily.

then with the ultrathrust muffler I switched to APC 10x9 running at 14300 rpm static - unloads really good in the air as well.

There is no reason to believe that this engine was designed to be loaded with .75 size propellers.. with those huge props, this engine cannot produce any reasonable power..

DarZeelon

Quote:

ORIGINAL: jeffk464

...but a 12x6 need to turn faster then a 12x7 to pull the same RPM.

Jeff,


You mean, to attain the same flight-speed... RPM is how fast the engine and the prop are turning.
Yes, a 6" pitch prop needs to spin 1/6th faster than a 7" pitch prop. That is nearly 17% more, or ~2,000 RPM where your engine is running.


And as to speed; if you want your plane to fly more slowly than it does, exercise throttle management...
You really don't need to fly that trainer at light-speed, so full-throttle should be avoided in most flight circumstances.

Reduce the throttle until you are comfortable with the speed (but not too close to stall-speed...[>:] ).

jeffk464

Oops, I meant to say to pull the same amount air(thrust) not rpm.

Oly

Hi DarZeelon,
I really appreciate your advice and input on these forums, you certainly know your stuff. As per a few posts ago, I run Cool Power in my two stroke engines and have found they do well on this fuel. I do make every effort to not run them too lean/hot as this can damage/ruin them.

Because of my experience running this fuel, I guess I'm not convinced that castor oil is essential.

Again, thanks for your input.

Oly

DarZeelon

Oly,


Thank you for appreciating my efforts [8D]...

As to 'Cruel Power'... Morgan Fuels themselves (the CP manufacturer) recommend [link=http://www.morganfuel.com/omega_main.htm]only their own Omegaâ„¢[/link] and NOT this fuel, for ABC/ABN engines. But CP should initially be OK for ringed, ball bearing engines. ...And even then you are much more likely to encounter bearing problems with this no-castor fuel. Just search this forum on OS bearings...

Since neither Morgan, nor OS recommend this fuel for ABC/ABN engines, I believe there is very good reason for you to limit its use to your engines that do not have a tapered cylinder bore.

As to older style meehanite-steel engines (iron piston) and bushing-bearing engines; CP is like hydrochloric acid... Keep away from it! Only very high castor fuels (not even Omegaâ„¢) should be used in them.

XJet

Dar speaks the truth - ignore his sage advice at your peril :-)

bgee

Would a OS 50sx Bisson pitts muffler work ok with a 55ax?

DarZeelon

Quote:

ORIGINAL: bgee

Would an OS.50SX Bisson Pitts muffler work OK with a .55AX?

BGee,


It has the same bolt spacing, so it will fit directly...

How it will affect performance and fuel-pressure? I can't say...

Nehru

O.S. 55AX is a very good and strong engine I use this engine on my modified PT-40. which can Tow a Banner and carry half a kilo weight in the fuselage box which has a hatch. the engine runs well at all speeds.

Rambler45

One of the major problem I got with this engine is that it is so quiet
I can hardly hear it when up in the air, especially when somebody is up there as well.

Thought of pulling the baffles out just for the noise.

It got this PowerBox E3020 on it, which looks rather very business like.
But I just got another 55ax and this one came in a E3070 muffler not as good looking, not sure how that perform.
Did ask Bax here and he says they do sometimes change along the production line.

rainedave

My Feedback: (1)

I would really like to see a photo of the E3070 next to the E3020. I've searched the web and Tower and can't find one. Also, does anyone know the number on the AX .75 muffler and how it differs from the AX .55 muffler? It costs $16 more than the E3020!

David

Rambler45

rainedave

here you go mate
hope you can see it

rainedave

My Feedback: (1)

Thanks R45. I think I like the 3020 Powerbox better. Is the performance the same for both?

David

Rambler45

rainedave

I like the E3020 better from looks point of view.
But one problem with it that I notice, is that it did not come, at least on mine, with a rubber O ring between the muffler halfs.
Consequently I notice some leakages out thru the joint there.
The E3070 does come with one
But I just got the motor and eventually mounting it on a Ultimate BiPe using a slimline muffler.
But will run using the muffler it came in first to run in the motor.
So I have no idea what would be the difference with the 2 muffler.
#1 engine is still running in so not good idea to be changing things around.
I already had a rather bad crash over a deadstick landing.
Will change the muffler later and try it and see
But winter is hitting here rather hard at the moment, wind rain etc.

STICK MODE

well here it is my 5 cents worth dont jump read it all before throwing bricks back. I own 13 motors all OS 4 and 2 strokes and 2 jets might say im getting on( I was the one that fitted the OS outboard to the ark ) I think that the 55 has some problums i own 2 of them and a friend 3. Firstly forget running it on 10% nitro "it hates it " its a ***** to tune why? i belive OS has over carbed it .Sure it runs nice down low and the middle range but up top runs out of puff =leans out so just to be a pain i changed the plug from a OS8 med to a OSA3 =hot ran it on 15% and low and behold i finely got it to ring out my reasoning is that by running a hotter plug + more nitro you lift the compresion same as some futher back in the thread has stated by reshiming the head ( DarZeelon )i belive listen to this GUY he knows tickers love his statement about castor ( well said my friend you cant go past it )in fact his quoit= your OS. 55AX and all other tapered-bore engines, will run considerably better and will last much longer, on fuel with a good deal of castor oil in the lubricant package and not with too much nitro... end of qoite now before you go racing of and buying 20 and 30% nitro do some checking any tapered bore motor will benefit from nitro up to 20% after that save you money and buy me a beer it will be wasted also the tank needs lots of presseure another indication of too big a carb but with the 46AX no worrys ( smaller carb )any thoughts on this are more than welcome but out of the 22 55AXmotors I know of all problums are the same =lean out at the high end and finickey to tune best regards Frank ( President Woodburn flying club SouthIsland New Zealand

thesouth1

I got a Pitts on my 55 AX, no pressure problems to date, Thought there was going to be at the run-in so I plugged a exhaust tip and ran a tank like that. The day I planned to fly it I unplugged and retuned. Going great so far. Would anyone like pics?

gem2

Thanks for info on that pitts muffler working out so its ok on 55ax and with no pressure problems..............what about using a backflow check valve on the muffler pressure line to tank.......will that result in too much pressure...or you don't know.......anybody know... I used one on my old magnum and the pressure increase caused the fuel to flow out from around needle valve......engine ran kind of poorly I'd say with the check valve or backflow valve so I took it off and no more leaking ...engine ran ok again....................