sgtshultz

My Feedback: (28)

Looking for some feedback on the 3w-70B2 please.

rc bugman

My Feedback: (30)

What do you need to know? I have a couple of them and love them. Weight is 4.95 lbs which is light for a twin. Being an older 3w, they don't have the power of the current line but equal about a 3w-60 single but a lot smoother. I have one mounted on a wildhare ultimate and one mounted on a GP Pitts. Both planes have unlimited vertical and weigh in the area of 19-21 lbs. Prop = 24 x 10. The engine is happiest around 7000 rpms.

If you want to know more, just ask.

Elson

sgtshultz

My Feedback: (28)

How much smoother is the twin 70 vs the single 60 please.


thanks

rc bugman

My Feedback: (30)

How much smoother is a 70 twin than a 60 single? Well, that is a value judgement. First of all, the 3w-60 single weighs more at 5.3 lbs vs 4.95 lbs. I personally do not like any single larger than the 50 cc due to higher vibration levels. For the first 10 flights on my WH ultimate, I had a 3w-75 single. The plane flew great with loads of power but the vibration levels were unacceptable and hard on the airframe. I replaced the 75 single with a 70 twin and have almost the same power but the plane is a whole lot happier with the reduced vibration levels. The 3w-75 went on the shelf along side the 3w-60 to either be sold or to wait for another project.

You will be very happy if you purchase a 3w-70 twin. It is one of 3w's sweet engines and I will probably purchase a 3rd one in the near future.

Elson

Supermod56

My Feedback: (36)

Great motor, had 2, if I could find another one new in the box I would buy it in a second!! Smooth and good power, 24X10 Menz is what it likes best. My 60 single runs great but shakes the bolts out of the plane!
Tom

barryco

Kent Norman / Sweden

I have an older 3W B2 mounted in a CAP 232 (span 125 cm, 10 kg). I can't get it to run properly in inverted flight nor knifeedge.
Its carburator is "hanging" under the engine using a 90 degree intake. Think I have tried all recommendations with no real improvements.

It sounds like it running rich inverted and starts to spit. I'm becoming used to it. At first it scared me, but now I don't really bother.
In Arestiflying it can be a little anoing. The engine is running great, but like to sit upright, who doesent............?

shakeelsid

Are you sure you have your 70-B2 in that small an airframe?

I have used some early examples of these engines years ago - we flew one briefly on a small UAV. In our application it did not do anything but straight and level sustained cruise for a few hours at a time. My recollection is that it was very easy starting, very very smooth and economical engine. I lost interest in the engine because it was too small. Given that we were using engines such a Limbach and TTL (which were very high standards for their day), 3W did not seem out of place, and was far cheaper.
3W has become very refined in the many years since, but I am sure a 70-B2 is still a fairly good engine - just dont think of it as a 70, but more like a souped up 50 and you would be very very happy.
Sid

barryco

Thanks for your soon reply shakeelsid. You are right, the span is 225 cm (30% sacle). The engine fits exactly within the cowl.

barryco

Got the answer from 3W support in Germany:
Your problem is the 90 degree intake (plastic). It will collect a small amount of gasoline at the bottom (because of low temperature).
When going inverted the engine gets to much fuel for a while.
It will be better if the intake was made of aluminium, but that is not available.

The solution is to mount the carburator direct on the engine. To do so you need a kit
from 3W (part no: 20.006.500). Its really what the call a "carburator plate"

Hope this will help some one out there

coronabob

My Feedback: (10)

Thank you, Barryco! I wil contact Cactus Aviation about the kit.

Supermod56

My Feedback: (36)

I just got another 70 twin, first thing I did was buy the angled aluminum "intake manifold" from Aircraft International, ran those on my other 70's and 78, no Phenolic block leaks to deal with, and it puts the carb out of the air stream. They work great
Tom

TheEdge

My Feedback: (788)

I have one of these NIB with Johnson smoke mufflers I wish to sell.

arobatx

PM me with more information, pictures, and your asking price.

les2097

My Feedback: (508)

How much Edge...??

Thanks

Larry
[email protected]

TheEdge

My Feedback: (788)

Sold already but someone just posted a used one for sale

coronabob

My Feedback: (10)

I will sell mine for $400. It has been converted by 3W to single prop bolt. Runs very well.