DeviousDave

I've never seen one of these before, while visiting RocketRob 2 weeks ago in San Fran he gave me three of these engines to take home.

Are they good runners? They seem 'sturdy', which is perfect for a project I have in mind that needs two heavy engines as there essentially isn't a nose on the airplane.

Mr Cox

The Webra 1.5cc Sport is unfortunately a bit anemic. It is a simple cross-flow design with a flat head piston...
I don't remember exactly what mine did but expect around 14-15000rpm on a 7x3 prop, and use plenty of castor in the fuel.

The Webra Speedy 1.8cc and the 2.0cc (ABC) with the rear exhaust, are much better.

DeviousDave

So, about like an OS .10FP then?

Mr Cox

No, they are weaker than a typical .07 engine...

The OS .10FP will make around 16000rpm on a 7x4 prop, as a comparison.

DeviousDave

That's not promising...

Mr Cox

No, it was a real disappointment when I first ran it. I also had a look inside, it is a simple crossflow design, but they forgot to put the important baffle on the piston...

Perhaps it began as a diesel design and then also offered as glow, I don't know.
The engine to have in this size from webra is the Speedy 1.8cc or even better 2.0cc;

JohnAV8R

The Webra Speedy 1.8 cc (MAS 7x4) is a fantastic little engine. On my "Wild Thing" it easily keeps up with an Enya .15 (2.5 cc). It is lighter than an MVVS 2.0 cc and has the same power. The only disadvantage (for me anyway) is that it uses its own glow head. I have drilled and tapped the old glow head for a standard glow plug. Not much power was lost.

dennis

My Feedback: (90)

The Webra 12 that I have is a jewel. Rear exhaust and ball bearing and pricey at $129.95 when I bought it. The muffler was extra as it did not come with the engine. Power was there and would keep up with most of the decent sport 15's of the day. Somehow or another I lost the needle valve in storage and after 2 years of trying to get a replacement I gave up and converted it to a control line engine. I really need to find a design that moves me to get this little jewel back in the air

Mr Cox

I got a little curious about the engine again, so I dug out my 1.5cc from the bottom of a shoe-box and gave it a little bench run...

I have worked a little on the crank inlet before and also added an muffler pressure fitting, but appart from that it is all stock. It is not quite as bad as I remembered, on 8% nitro and 25% all castor I get the following numbers;

APC 7x4; 13400 rpm (feels a little overloaded at full throttle)
APC 7x3; 16200 rpm (good throttle response)

It idles down to about 5000-6000rpm, but it is not possible to tune on the airbleed with the engine running. It is also best to wear a glove, as the airbleed screw tends to cut the finger tip when flipping the engine...

JohnAV8R

What about if you turned the carb around and had the air bleed screw at the back and out of the way? I have a small engine set up that way, but I am not sure if it came that way intentionally, or in error.

ffkiwi

I don't think it makes a huge amount of difference-though I'd expect to see a very slight difference in setting between a front facing airbleed and a rear facing one-due to the ram effect of the prop slipstream-but given we are talking at idling speeds this would be fairly small...I have seen over the years some engines with the bleed opening on the rear face of the carb.

ChrisM
'ffkiwi'

Mr Cox

In terms of function the airbleed could well be facing backwards by rotating the whole carb 90°, I have done that on other engines.
On this engine though the carb is very asymmetric in shape, it doesn't show so well in the pictures above, but the section with the airbleed screw is sitting on a bulge on the carb. This bulge puts the screw very close to the prop, and it will also hit the cylinder if one rotates everything by 90°.

Mr Cox

I just checked my computer for some more info and found a parts diagram with the different versions, it did come as a diesel, glow (airplane), and car engine (larger head). The carbs seems to have varied over the years, the early ones look a bit like the MVVS ones, while I have the later version which is common with the 1.8 and 2cc "Speedy" engine.

I have a used airplane engine and a NIB car-engine, but none of the diesel ones...

Mr Cox

After a bit of "googling" I found a picture of the diesel version too. The pretty anodizing of the head should be a warning sign. Any engines that need pretty colors in order to sell, usually don't deliver much in terms of performance...

JohnAV8R

" Any engines that need pretty colors in order to sell, usually don't deliver much in terms of performance... "
Well, I guess I'm guilty as he** on that note. I've always been a sucker for the anodized muffin colours.
John

Mr Cox

I feel a bit guilty now about the carb, I hadn't actually tried to rotate it, it just looked impossible. Turns out that they have given just enough of chamfer to the bulge to allow for a rotation...

So with a new hex screw installed, instead of the slotted stock one (a regular M2x8 machine screw) and with the carb rotated 90°, it will now be possible to tune on the low-end while running the engine, great!

Mr Cox

I just realized that these engines are very similar to the LST engines. I have one of them in diesel form, but I know very little about them. They are/were made in Lithuania and it certainly looks like they were inspired by Webra, or possibly the otherway around...

Same thing here though, one single transfer port (opposite to the exhaust) and no baffle on the piston. The muffler is kind of cute though...

aspeed

Nice muffler, it likely seals good, and there is a nipple on the back so an extension won't fall off.

JohnAV8R

size--next to a Pee Wee .020
LH diesel has air bleed set at the back
RH diesel has air bleed at the front

jetpack

My Feedback: (1)

MJD

My Feedback: (1)

When you turn the carb 90 degrees, do you recommend putting the needle valve into the prop arc, or into the cylinder?

Agree on engine colors- but there are a few exceptions. The purple West .50/.52 for example. Hmm, what else now..

Mr Cox

Ooops that's a really bad/silly typo, it should read 180° degrees of coarse...
Or you would have to rotate the whole engine the reminding 90°...