rainedave

My Feedback: (1)

A while back I won this X.11 off the auction site. The first time I ran it fuel was bubbling out around the glow plug and from under the head. I don't have any machining tools (or machining knowledge) so I did what I could by hand. I took a Cox piston, coated it with Wright's Copper Cream and swirled it around where the glow plug washer seats on the head. I also put some on the top edge of the sleeve and twisted it against the head. It worked. It no longer bubbles fuel.

I ran the engine with a wood Zinger 7x4 with the square tips rounded off with sand paper and then re-balanced. I used Sig 25% nitro Champion fuel.

Here are two peak readings I got. It was turning steady just above 19,000 with the needle valve richened a bit from peak. I don't know if these are good numbers or not for this engine, but I thought I'd post them.

David

combatpigg

My Feedback: (3)

RD, if you plan on using this engine a lot, make sure that every screw on the carb is locktited and tight and checked often until you're confident everything is going to remain "just so".
I think the performance is good enough here to justify residence in a SureShark, BabyBirdy or a MachNone! I'll bet a ~6x4.5 or 5x5 prop would be worth trying on a fast plane?
Come to think of it, APC has a prop listed for .10 pylon, but it's probably one of those $3.95 specials instead of the $1.83 industrial grade type.

lfinney

My Feedback: (44)

those are excellent numbers, its still a sleeve bearing engines, give it 20 more tankfuls and you will see the real performance of this little jewel!
i ran one of these on a quickie 200 with a mac's pipe! it sure cleared the local flying site[8D]....

RocketRob

My Feedback: (1)

Dave,

At initial look the revs sound pretty respectable!

I think it is better than an OS 10 or Webra .09 - the wood prop is a bit of a variable.

Is the engine heavy? looks like it might be a bit heavy for the displacement?

rainedave

My Feedback: (1)

It weighs 170grms, or 6ozs. A lot of that is the muffler. This version has a single ball bearing on the rear of the crank.

So, I guess it's a two-part answer: the performance is good for .11ci of displacement, but not so good for 6ozs of metal.

I will try some other props and post the results. I have a Cox gray 5.5x4 that I'll bolt on next.

David

controlliner

Dave, definitely use castor oil fuel. The conrod in this engine is unbushed. I have an earlier "Bluehead" version which I have broken in well on castor based fuel. The later X .11 like you have now, I had and I ran it on fuel with a castor/synthetic blend and the lower end of the rod wanked out in no time. This was with TopFlite 7X4's

build light

This has been relatively true for most .10 size engines from what I have read. Check and you will find that .15 size engines weigh only slightly more yet have 50% more displacement.

Robert

mtntopgeo

My Feedback: (12)

One of 3 possibilities; (1) You've got a very good running X11, (2) I've got a very poor running X11, or, (3) That is one very "funky" 7x4 prop that you're using. i've always considered my ST (blue head version) to be a very heavy .074 Norvel (performancewise). Also that enormous carb sure don't help make it very user friendly. ............................. George K.

combatpigg

My Feedback: (3)

Well, RD did mention he rounded the tips off.....?

rainedave

My Feedback: (1)

It's more like a 6.875" x 4" with the modified tips.

I removed the restrictor from my carb. It still works well. For me, the trick with all ST carbs of any size is to set the low speed needle so lean that the engine dies when advanced from idle. Then, very gradually richen it one click at a time until it no longer cuts out when advanved. Working the other way - rich to lean - has always been a real pain for me, so I go the opposite way. After the low speed needle is set using that method, I will rotate the spray bar a tiny bit at a time until the midrange is no longer too rich. Then, they work as well as any other carb I've ever owned.

David

Dan Vincent

The ST X-11 engines were great performers. I remember the free-flight guys loving these engines with a straight venturi.

The first one was the blue head version in 1978 and the natural aluminum version was a few years later. Both were avilable in plain-bearing or single BB.

rainedave

My Feedback: (1)

I think they're worth owning simply for the cool factor. My Blue head, which I bought used, is down on power. The more restrictive muffler robs some power, too. I'm always looking out for another one.

David

skaliwag

My Feedback: (1)

At last count I have 11 of ST X11's.. All of my Natural finish heads are BB and the Blue are plain.  I gave my machinist  friend a Blue one and he made a diesel head for it
Runs and idles great which really is surprising with the huge black hole that the 15 size carb has. Some of them have a restrictor.
Unfortunately it won't work on the BB version, different all around.

DeviousDave

Holy Moly! If I'd have know these engines were that fast I'd have had one years ago. 20k on a 7ishx4 ain't no joke. My only .10 experience is with the OS .10 and that little guy can barely pull the skim off of warm milk. I've got a few more motors in this size range but never used them as other projects got in the way.

skaliwag

My Feedback: (1)

OK you boys that have the "need for speed" and have one squirreled away somewhere.... Wonder what one would do with a pipe on it and a pylon style (Small dia, Large pitch) prop?

Also ... Anyone know why they made an .11ci (1.79cc)?

rainedave

My Feedback: (1)

Maybe they were designed by Nigel Tufnel.

David

Dan Vincent

Here's another engine from the time of the ST X-11 Bluehead; the Webra .10 "Speedy" with dual BB shaft.

skaliwag

My Feedback: (1)

Dave... These thing came from Italia, they are Super Tigre Motori, made by craftmen.  Not by Nigel, he's a Moroni.

DeviousDave

Piping it won't likely do much as the liner probably isn't timed for pipe use. Might get some results by playing with the liner height though. Never know though, Iknew a guy who claimed that the OS .10 responded to a pipe... As for why the .11 was not made as a .10, marketing would be my guess.

s. wallace

My Feedback: (24)

LMAO

Great movie...

gcb

Geez guys, this is a thirty year old design, don't expect it to run like today's engines. Enjoy it as it is.

George

balsaworks

It makes a decent diesel conversion too. No record of revs or prop I'm afraid, this photo was taken some years ago. It ran well but the throttle wasn't very impressive. Probably needs a smaller venturi as a diesel.

rainedave

My Feedback: (1)

balsaworks, you and mtntopgeo both commented about not liking the carb performance. What do you not like? Is it running too rich in the midrange? I'm curious because I really like ST carbs.

Thanks,
David

balsaworks

Yes I agree Dave, the ST carbs are great, but somehow this dieselized setup wouldn't play. I couldn't get any sort of idle, although I admit I didn´t spend a lot of time with it. No doubt it can be sorted out

combatpigg

My Feedback: (3)

balsaworks, adapt a AP .061 carb to it, it will work great. I did the same to a PAW .15 last year.

I'm glad to see so much interest in the ST .11s. I thought I heard once why .11s were produced, it had to do with competition.....but I can't remember who, what or why.