the Wasp

My Feedback: (1)

"see photo below"

now now boys before you jump on me about Super Tartan let me tell you what I have found,,

for this post I will be comparing this 44cc Tartan Twin to my MVVS 35cc,, why, because I want to move my MVVS to a different plane and I would like more speed from the plane my MVVS is in,,

A) yes, many times I have talked to Jim Cline, the Tartan guru of the 20th century,,

1) weight,, both engines (stock) on the plane ready for flight, the Tartan Twin "glow" is 9oz lighter than my MVVS 35cc gasser,,

2) a CH ignition with battery will bring the Tartan's weight up just about 9oz, that will make the weight of the two engines just about the same,,

3) the Tartan is a high RPM engine,, my goal is NOT to spin a larger diameter prop, my goal is to spin more RPMs,, the Tartan Twin should spin the same prop (3W 20x8) about 600 RPM higher than my MVVS,, these Tartan RPM numbers I got from researching RCU and talking to Jim Cline,,

4) carburetor,,, for the engine size of 44cc the Tartan has a very small carb on it, this carb's I.D. is at-least 2mm smaller than my MVVS 35 carb,, so with that if I needed more power I could replace the stock carb with a larger carb, such as a carb off a ZDZ 40 or Brison 40 or even a carb off a MVVS 35,,

5) the Tartan should idle some 300 to 400 RPM lower than my MVVS,,

6) Twins vibrate less than a single,,

7) Bisson makes larger mufflers for the Tartan, larger muffler should raise power over the stock mufflers

8) synthetic oil can be used in the Tartan, so no more Castor,,

9) for the money I have in this Tartan converting it to a gasser would be cheaper than buying a new 40cc gasser,,

as I said I am not looking to spin a larger prop, I want more RPMs,, while fine tuning my MVVS for it's final adjustment I found that just a small difference of 300 RPMs is significant to the top speed of my ARF 82" GeeBee Y, getting another 600 or so RPMs should get my Gee Bee Y's top speed up close to 90 MPH,,,,,,, cool !!

what yeea think guys ??
Jim

soarrich

My Feedback: (98)

Does the Tartan have roller bearings on both ends of the con rod? If it does it should be OK.

captinjohn

My opinion is...gas & ignition is not going to make it faster. The use of Glow fuel & Nitro may with right tuning. You can buy menthanol for $3.75 a gallon or less and use Klotz oil for lube. Nitro can be had at some speed shops or online. Less weight & no ignition parts with the bonus if no Radio glitches...is a real bonus. Capt,n

the Wasp

My Feedback: (1)

""gas & ignition is not going to make it faster""

right, but it should be a higher RPM engine than my MVVS,, accordingly to Jim Cline I should loose about 300 RPM converting it to gasoline, this is with the stock carb, so at that it should turn the 3W 20x8 around 7600, if not then a larger carb would help..

Jim

the Wasp

My Feedback: (1)

soarrich ,,, sorry, yes it has roller bearings on the lower rod end..

Jim

Charley

My Feedback: (2)

Converting the Tartan to ignition is a good idea even if you ran straight alky in it. I know a guy who crashed a big Cap because the tartan hiccupped and started running backwards, reportedly a common malady. The ignition would make it more reliable and get you a lower idle. Also it would be easier to start. Are you sure about the shaking? I thought the Tartan was a boxer.

If all you're after is more speed on the GeeBee, why not try more pitch first?

CR

gkamysz

My Feedback: (19)

The boxer configuration will make the least vibration. Boxer is the typical two stroke opposed cylinder twin configuration.

Charley

My Feedback: (2)

Huh-uh. In boxers the pistons reach TDC simultaneously.

CR

Edit: We may be hung up on semantics. Smoothest running flat twins I've been around are the alternately firing twins.

the Wasp

My Feedback: (1)

I just checked it,, as I knew, both pistons reach TDC at the same time, these types of Opposed Twins vibrate less than any other twin's or single's,,

Charley ,,
"" I know a guy who crashed a big Cap because the tartan hiccupped and started running backwards""

yes this can happen with any read valve 2 stroke, and that problem comes from 1 or 2 of 2 things, running to rich on the low-end, and or to low an idle,,

""If all you're after is more speed on the GeeBee, why not try more pitch first?""

well if you mean run more pitch on my MVVS well I would have to go to a smaller diameter prop and if I did it would 1) not pull as well around 1/2 throttle, and I do now want that, and 2) as I said I want to move my MVVS to a different model..

thanks for the input guys !!
Jim

Antique

My Feedback: (4)

Name 1 horizontally opposed flat twin 2 cycle that fires alternately...

gkamysz

My Feedback: (19)

Because both pistons reach TDC at the same time the piston weight and counterweight cancel each other's movement. Boxer type engines are opposed flat engines where the opposing pistons reach TDC at the same time. There are no alternate firing two stroke boxers, unless you have separate crankcases for each cylinder. That is not common because it takes up a lot of space, so it might as well be built as an inline to reduce frontal area.

Alternate firing four stroke boxers will be the smoothest.

Saito has flat twin four strokes that are not boxers and share a common crank pin. These will vibrate a little more.

soarrich

My Feedback: (98)

I can!
Saito 100 Twin Cylinder ABC
http://www.horizonhobby.com/Products...arts%20Listing

Charley

My Feedback: (2)

I didn't specify 2 stroke.

CR

gkamysz

My Feedback: (19)

The topic is about a Tartan twin.

Charley

My Feedback: (2)

Not according to my research on Wiki. They're rough at low speeds. Look it up.

Have you ever tried more pitch w/same diameter? Might surprise you.

CR

the Wasp

My Feedback: (1)

""Not according to my research on Wiki. They're rough at low speeds. Look it up""

then I would have to question it's tuning !!


""Have you ever tried more pitch w/same diameter? Might surprise you""

yes I did, and my engine got so hot I had to richen it quite a bit, in the end I could get only 5500 out of it,,

MVVS 35cc gasser,,
3W 20x8 7200 tuned for flight
3W 20x10 5500 tuned for flight

I don't know why you are so stuck on my changing props, I need to move my MVVS to my other plane (see photo) for 2 reasons, 1) I sold the engine in it because the plane needs more power, 2) my Twin wont fit in it..

Charley

My Feedback: (2)

Not only; there's MVVS 35 in there, then we got off on boxers. Wassamatta you? Never heard of thread drift?

CR

soarrich

My Feedback: (98)

Wasp

Nice plane. Why would you put a flat twin in that? I'd sell the twin, if money's an issue, and buy one of the Chinese singles. DL, Area51, LS Pro, Cellmark, all have engines for less than $400. FTL52 is a 45cc and it's less than $200.

the Wasp

My Feedback: (1)

no no no
I want TO put the MVVS in the Red plane !!

and I want to put the Twin in my Gee Bee Y,,

this Twin is a better made engine than any Chinese engine that's for sure !!

Jim

captinjohn

I do not know the name...but it was a full size outboard motor! Capt,n

captinjohn

The Tartan Twin is a good made engine. I always wanted one and seen them at swap meets for sale. After I read a article in a RC magizine, I changed my mind. By the time the guy got it running at its best...he had a lot of money and work into it. His advice was to buy a different engine...already with the power you want. There was a Man in Florida that could make a Tartan sing. Tom ..... was his name. Best Regards capt,n

the Wasp

My Feedback: (1)

captainjohn,, you making me want to keep this engine more and more !!

as long as you have been in this hobby you should know by now that where some don't succeed others do,,

I wish you had a link to the article, I would love to read it to see what the guy was doing wrong,, I mean what could he have done to put so much extra money in it,,,

most likely his problem was ether the notorious Dellorto Italian carb, or to much nitro, or to much oil, or to cold plug,,, what else is there,,

if you do a search on RCU you will see they have plenty of power right out of the box,,

Jim

captinjohn

Wasp, I got most of that article ...some place????? I will look for it. I did not plan to do the(magizine) mods he done...but dicovered this Tartan twin genius (TOM)...and started looking again for a good like new Tartan. Next thing I knew this GuyTom did not post any more. Seems like the name Tom Perry ...rings a bell. Could be wrong on name! Indy RC sold them in Indiana. They sold more engines than most other places in there hay day! I still got a catalogue ...also pictures of at least 2 or more Tartan Twin engines. Best Regards capt,n

coralcape

My Feedback: (4)

I converted a Tartan twin to CH-rcexl just recently. It was originally glow and as stated neded on board glow to be dependable. I drilled out the heads for 10mm cm6 plugs. I have had it it in two planes now and am very pleased with it. It's a beautifully made engine and starts, runs and idles well. Good luck, red

Charley

My Feedback: (2)

Shoot, I don't care what you do, it's your equipment. I was just offering alternatives to your desire for more speed.

Regarding your prop/RPM data above, it's obvious that the engine was over-propped with the 20x10. Also, the 20x8 is right on the upper edge of the recommended prop range for the 35. Look here:
http://mvvs.nl/MVVS/main_bestanden/petrol.htm

Scroll down to the the 35 for prop range. This is Pe Reivers site. I don't think anyone knows more about MVVS engine applications than he does.

CR