Re: How was this Twin 049 made?

WingingIt74 Fri Mar 23, 2012 6:29 am

hmmm, nothing is impossible. You just need a crank assembly that comes apart or a piston rod that has a cap.

How was this Twin 049 made? - Page 2 Screen12

image from here:

WingingIt74 Fri Mar 23, 2012 9:35 am

This guy said he isn't taking the tank off either... What's wrong with these people???
How was this Twin 049 made? - Page 2 Screen11

WingingIt74 Fri Mar 23, 2012 10:13 am

RknRusty wrote:Ahrma_581, welcome to the forums. That guy in your avie looks like Reverend Jim Ignatowski.

http://www.cbs8.com/Global/story.asp?S=13209288

**RknRusty** Fri Mar 23, 2012 10:51 am

RknRusty wrote:I sent him this question:
In the picture, one piston looks to be up while the other is down. How can it pull an intake vacuum or compress the fuel/air charge in the crankcase with the pistons working against each other? Am I missing something? Any chance you could take off the tank and show a picture of the rotating assembly? And the venturi too.
Interesting engine. Thanks,
Rusty

His answer, as we know was:
Dear rknrusty,

sorry, i am not going to take the engine apart. i do not know auything else about it. what you see is what you are purchasing.
- widow315

**RknRusty** Fri Mar 23, 2012 10:52 am

WingingIt74 wrote:
RknRusty wrote:Ahrma_581, welcome to the forums. That guy in your avie looks like Reverend Jim Ignatowski.
http://www.cbs8.com/Global/story.asp?S=13209288

I liked it better when I thought it was Reverend Jim. Laughing

ahrma_581 Fri Mar 23, 2012 12:37 pm

WingingIt74 wrote:
RknRusty wrote:Ahrma_581, welcome to the forums. That guy in your avie looks like Reverend Jim Ignatowski.
http://www.cbs8.com/Global/story.asp?S=13209288

That's funny, I'd forgotten where it came from. Just so we're clear, I'm neither the father nor the son in that article!!!

WingingIt74 Fri Mar 23, 2012 1:29 pm

ahrma_581 wrote:
WingingIt74 wrote:
RknRusty wrote:Ahrma_581, welcome to the forums. That guy in your avie looks like Reverend Jim Ignatowski.
http://www.cbs8.com/Global/story.asp?S=13209288

That's funny, I'd forgotten where it came from. Just so we're clear, I'm neither the father nor the son in that article!!!

microflitedude Fri Mar 23, 2012 1:40 pm

That's a car crankcase on the twin...

nitroairplane Fri Mar 23, 2012 1:45 pm

Big Al wrote:
WingingIt74 wrote:More precisely the crank. I can see how the case was made. I assume it just has a longer crank pin to accommodate both pistons? Ideally you would want them something like 90º from each other?

It's sprouted my imagination on trying to figure out and maybe building one.

http://www.ebay.com/itm/260982078736?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1156
Several years ago that same engine (or one identical to it) was on eBay. At the time I also wondered if it could be a runner. I did a layout using stock Cox parts with thoughts of duplicating it and at first glance it looked like it might be possible by using a silver soldered crank assy. But alas, (see sketch) there was a serious fly in that ointment.

Possible if you could do the second part as a screw on.

andrew Fri Mar 23, 2012 4:38 pm

Many times the second web is pressed on --- this is fairly common on multi-cylinder 2 stroke engines with needle bearings on the lower end of the rod.

But, in any case, I agree that the piston postions are problematic. To get the necessary crankcase vacuum and compression, the pistons should be mounted on the crank 180 degrees apart. Induction could be either reed or rotary disk. The picture clearly shows one exhaust port open and the second port covered by the piston. It may be that one of the rods or the rear web has snapped and only one piston functions.

Rotary disk induction may be more appropriate since a reed valve would require that the second throw be fully floating and unsupported. A rotary valve would add some rotational drag, but would support the rear rod journal.

andrew

WingingIt74 Mon Mar 26, 2012 8:47 am

Twins coming out of the woodwork lol!

At least this seller is truthful in that they said it doesn't run.

http://www.ebay.com/itm/UNIQUE-COX-TWIN-CYLINDER-049-MODEL-AIRPLANE-ENGINE-/230767275537?pt=Radio_Control_Parts_Accessories&hash=item35bacd2e11#ht_4157wt_1224
How was this Twin 049 made? - Page 2 Kgrhqv10

How was this Twin 049 made? - Page 2 Kgrhqv10

**Cribbs74** Mon Mar 26, 2012 9:02 am

The crankcase on that one was done well.

WingingIt74 Mon Mar 26, 2012 9:22 am

cribbs74 wrote:The crankcase on that one was done well.

Not sure if it's any better or not...
How was this Twin 049 made? - Page 2 55806810

I guess you could do a threaded insert, can't tell with this one.

Godsey3.0 Mon Mar 26, 2012 12:27 pm

http://community-2.webtv.net/injunnut/UniqueSMALLModel/

altidsulten Mon Mar 26, 2012 2:14 pm

Nice engines in that link, but unfortunately the link in the article is dead. I would really like to see how he had made the crank.
Regards
Thomas

robot797 Wed Jul 31, 2013 1:16 pm

does anyone know were one does get a working engine like that

i need one for a boat i am building

WingingIt74 Wed Jul 31, 2013 1:19 pm

They are all custom engines. Opposing cylinders in such a small crank case do not work.

robot797 Wed Jul 31, 2013 1:25 pm

to bad

Jason_WI Wed Jul 31, 2013 6:15 pm

If you want a twin that runs look for a geared twin such as the Selena products geared twin. They pop up on ebay from time to time.

How was this Twin 049 made? - Page 2 6d7cfb845b3ab30556fa6c120035d597_zps232e266c

anm2 Wed Jul 31, 2013 6:52 pm

Jason_WI wrote:If you want a twin that runs look for a geared twin such as the Selena products geared twin. They pop up on ebay from time to time.

I do not understand the point of this engine. It looks really heavy, and if I wanted something with twice the power of an .049 I would buy a .09 engine. In fact, I would probably buy a .15 engine. The medallion .15 I have is probably the best engine I have used. This seems like a lot of work, for something that is nothing more than a curio. Is there some competition that uses this engine, that I am not aware of? Thanks, Andy

andrew Wed Jul 31, 2013 10:09 pm

anm2 wrote:This seems like a lot of work, for something that is nothing more than a curio. Is there some competition that uses this engine, that I am not aware of? Thanks, Andy

For some folks, it's the trip getting there, not the end of the journey.

dinsdale Thu Aug 01, 2013 6:10 am

WingingIt74 wrote:It's not the only one built like that. Which kinda makes me curious. This one is also on ebay right now, just not as pretty.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130667422142&fromMakeTrack=true#ht_500wt_1108

Notice that with this engine there is no offset between the cylinders, as there is with the 1st one (top). I can't see how this one will work, but the 1st one has the offset presumably to accommodate the 180° crankshaft.

**RknRusty** Thu Aug 01, 2013 8:21 am

Aw man, what a waste of a 128tpi NV. Rolling Eyes

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