So, if they made one who would buy it? - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Sep 29, 2017, 08:35 PM
1977 kawasaki kd100-m
smallengines1284's Avatar
Question

So, if they made one who would buy it?


If Cox international started producing new crankcases for reedies and TDs to convert standard engines into 2 cylinder V twin engines would you buy one of them?
Sign up now
to remove ads between posts
Sep 29, 2017, 08:48 PM
Now I have to land that thing?
PGregory's Avatar
$50 + shipping
Sep 29, 2017, 09:31 PM
Registered User
toad007's Avatar
I probably would not. This has already been tried, I dont think there would be a market large enough to be profitable.
Sep 29, 2017, 11:18 PM
Registered User
In the "V" configuration I probably would not, but in a horizontal opposed configuration I probably would if it wasn't priced too high.....like under 35.00 dollars or so.

Mike
Sep 30, 2017, 07:13 AM
Registered User
toad007's Avatar
The difficulty is not in the cases, It is in making the cranks for dual throw at the same time or dividing and sealing the two case chambers and two reed system in order to fire alternating. two needles , etc, just not viable in this size. I suggest you make an engine first, as several of us have. It is a lot of fun and you learn a lot. Keeping it simple is hard enough.
Last edited by toad007; Sep 30, 2017 at 07:22 AM. Reason: added comment
Sep 30, 2017, 08:36 AM
Dieselized User
gkamysz's Avatar
http://www.ebay.com/itm/292107321002

Build it and they will come?
Sep 30, 2017, 09:31 AM
Rough Landing
rainyday101's Avatar
Quote:
Originally Posted by gkamysz
http://www.ebay.com/itm/292107321002

Build it and they will come?
That is a cool engine, but in my opinion it is a overpriced novelty with a small market. A used OS 10 FP or LA will do more for less money. None the less, some collector will buy one.

I question the power to weight ratio on that design.
Sep 30, 2017, 10:03 AM
Now I have to land that thing?
PGregory's Avatar
Wouldn't opposed cylinder config show less vibration?
Is it easier porting-wise to do V than opposed?
Sep 30, 2017, 11:34 AM
Registered User
surfer_kris's Avatar
The pictured V-engine seems to have a common crankcase? So that is wasting a lot of power ,running with 45 timing separation....

A boxer with simultaneous firing would work, and that has also been done it the past. Even then the power to weigh ratio makes them unpractical. As an example take a look at the G-Mark twin .12cc.
Sep 30, 2017, 12:41 PM
Registered User
Does seem as a ..lot... of metal, let alone a lot of work for a 2 stroke Hardly Davidson motor imitation /configuration.
Someone had Too much time on their hands.. seems as the only credible guess.
Sep 30, 2017, 01:20 PM
Rough Landing
rainyday101's Avatar
It might be impractical, but you have love that innovative spirit. I have made several things through life that were neat and innovative, but also impractical. Sometimes we make things just because we can. Gotta love it!
Sep 30, 2017, 01:44 PM
Dieselized User
gkamysz's Avatar
There are countless Cox based twins out there. I have my own designs, just have to actually build them. The market is certainly collectors or enthusiasts.

The crank is the hard part. Also, if you aren't prepared to do a significant amount of machining the crankcase can be bulky.
Sep 30, 2017, 01:49 PM
1977 kawasaki kd100-m
smallengines1284's Avatar
the plan originally was to make a v twin but I think a horizontal boxer would be a lot more practical in the sense of it being more scale on a cub to have the 2 cylinders poking out the sides and less vibration but then theres a problem with crank case pressure. because its always the same pressure inside the crankcase so it would have to run a muffler with pressure fittings. the design I'm going for would be a normal crankcase with an added cylinder at 180 degrees and set a little further forward with, a crankpin twice as long as original so it could fit a 2nd conrod.
Sep 30, 2017, 01:59 PM
Dieselized User
gkamysz's Avatar
Common crank pin opposed twin two stroke has no crankcase scavenging. There aren't any in this configuration because it won't run without an additional pump.

Boxer indicates two crank throws. This is the normal configuration for opposed twin two strokes. With one piece connecting rods this presents other challenges.
Sep 30, 2017, 04:28 PM
Registered User
The one on Ebaie doesn't look too outrageous for the price, but notice, it is not guaranteed to run. Sort of reminds me of an old magazine plane that used a Fox .35 with a necked down venturi, and plugged up exhaust to run slow enough for the plane. There was no throttle. He brazed another dummy cylinder on to the crankcase with no sleeve or piston. It really looked kind of cool.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question Anti-bluescreen device - if non existent, who would buy one? montymintypie FPV Talk 133 Sep 20, 2017 06:59 PM
Discussion If Monsanto would do it...... So would Soros, or the DNC, or.... Dave Campbell Life, The Universe, and Politics 1 May 09, 2017 09:27 AM
Discussion If Sweden and Germany Became US States, They Would be Among the Poorest States MtnGoat Life, The Universe, and Politics 2 Nov 03, 2015 01:54 AM
Discussion If Sweden and Germany Became US States, They Would be Among the Poorest States Indiana_Geoff Life, The Universe, and Politics 13 Oct 29, 2015 09:21 AM
Poll Which Jet would you buy if they build it? Turbobearcat Electric Ducted Fan Jet Talk 21 Aug 15, 2014 10:33 AM