My new ride !!

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TFF

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Apr 28, 2010
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Memphis, TN
First off that engine is cool.

My models are pretty traditional. The big and fast models are cool but they tend to find a group of owners just like real warbirds. They get the coverage. My .40-90 glow powered planes haven’t changed in essence in 50 years. No attention. I still have some .049 ones I’m thinking of breaking out. Piling in a $2500+ model defeats the purpose for models for me. They are cool and for someone else.
 

Bille Floyd

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Sep 26, 2019
Messages
797
OK -- so i took a picture of the serial number on the keel ; than
sent it off to Germany, the company that made the glider.

Turns out the D-tubes were made from the molds of the Tandem
glider, ( stronger) and the tip extensions , with winglets came from
the race model , (Go - Fast, with glide) . This is the only prototype ever
made from that combination ; and i Got it !!!!

First i plan to make a pod and break a bunch of glider records ; then
I will put an engine on it , to go fly a bunch just for the sake of flying !

Ask me how much I like to fly ; go ahead and ask ...
UAH ---- my X-wife Dumped me for my addiction , and
she was young and OK looking !!!! LOL

Bille
 

REVAN

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Joined
Dec 6, 2016
Messages
374
Location
Tucson, Arizona USA
Life is in my favor , for now ; check out the engine
that showed up, for my ride :

4 cylinder boxer style , 32-hp 4-stroke, with starter ; under
20 Lb . Spins a 40 X 12 prop, at 6K rpm ; won't need a reduction
unit, till I wanna take a passenger !!!

Not sure what i did right in life lately ; but I'm going
for the ride with pleasure !!

BilleView attachment 126893
Nice looking engine, but I noticed in the specs it lists "Fuel mixture: 1:50". How does that work if this is a 4-stroke? Is that an error in the spec sheet, or does this engine still use 2-stroke style fuel for lubrication?
 

TFF

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It’s a model airplane engine. Lube is in the fuel because the lower end is still like a 2 stroke for lubrication.
 

REVAN

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It’s a model airplane engine. Lube is in the fuel because the lower end is still like a 2 stroke for lubrication.
Is that 2-stroke oil mixed with regular unleaded gasoline (87 Octane), or some special model engine fuel?
Do you have a TBO estimate?
 
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TFF

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Unleaded. TBO unknown. If you haven’t messed with model airplane engines, you run them until you can’t. Rebuild them if you can. I have never had anything that grand, but I have some that are over 50 years old that run fine and some that are 10 that don’t. A lot goes into care and a lot is about quality. Trying to get more hp out of one by running it lean will cook one quick. Too rich will ruin one too.
 

wsimpso1

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Hmm. 310 cc is 19 in^3. Four stroke engines will generally make about 1 ft-lb per cubic inch (peak), so 19 ft-lb. If it is making that somewhere around 5252 rpm (seems reasonable for 6000 redline) that 19 hp. If instead you are prop limited at say 4000rpm and it makes 19 ft-lb then it is about 14 hp. Your horsepower estimate looks about right...

What gets my attention is the oil mixed fuel. Lube like a two stroke makes me think "potentially short lived engine". Even if parts are conservatively sized so they will live, keep power up to keep plugs clean...
 

TFF

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Engines this size will have roller or ball bearings for the mains and rods. It’s oiled like a chainsaw or weed whacker. The oil in the fuel migrates into the bearings and are usually only a problem if cheap bearings are used, and cheap oil. Rings and cylinders just like most engines are what becomes the issue. It’s a small bespoke engine going on a glider, not circumnavigating the globe non stop. Short lived is relative. 200 hours of run time is probably equivalent to 1000 of flying. That’s a lot of flying. It’s not meant to be a Lycoming in a Cessna. I would call it Experimental aviation.
 

pylon500

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Taree Airport Australia
Oil migrating past the rings to lubricate the big-end sounds a bit counter productive to me, to say nothing of the crankcase pressure build up, must be oil going everywhere.
For those not familiar the Rotax 912 series of engines, they use this minuscule piston blow-by to pressurise the crankcase and force the case oil back to the dry sump tank, but that oil was pushed through all the working bits by the oil pump first before it ended up in the bottom of the crankcase.
I'd be assuming there is a quantity of oil, splash lubricating around in the case...?
 

proppastie

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potentially short lived engine
On a powered launch UL glider the assumption is one is high enough at the quitting point to enable a turn around or safe abort......as it is a glider the assumption also is there will be enough lift for pleasurable flights, if not sled rides down are also fun.
 

TFF

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The model airplane 4 strokes have been doing it successfully since the early 70s, when they became off the shelf. We are also talking about an entire engine that is about the same size as two 912 cylinders. It’s not big. It’s just a couple of handfuls of engine. It would be like operating a Cri Cri. Those are just model engines too. Or Two if you get the joke.
 
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