Kris^

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for those interested, there is a report on the engines first flight, as well as some tach readings and general impressions about the engine in the review I am doing on it.

Here is the link:

BME review

Diablo-RCU

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More discussion on overheating. I agree that you have to use the proper air-fuel ratio. Too lean and the piston temperature rises too high. But, you also need to remove heat with adequate airflow over the cylinders. If you don't get enough airflow to cool the cylinders, the piston temperature also rises and bad things will happen. It's really no different than if you drained the radiator in your car and started to drive down the road. Even with the proper fuel mixture, the engine temp would rise quickly, then detonation, then seizure.

rmh

drain the radiator?
Cadillac claimed their engine design would tolerate this kind of abuse - --on TV a few years back.
Most people did not buy their cars anyway - so there was no big rush to form a class action .
( My only Caddie was a huge Coupe DeVille - --which my wife refused to drive- )

they switched the on/off times on cyls to compensate - or some other idea like that
All of my engines stand up well to normal ab/ use -- but I had pushed the envelope.
Back when Khris was a tyke ( 1957)
or ?- I street raced with a jimmy blower on a two ton Olds sedan .
The mag was always tweaked to the limit and the belt (Poly V) was squirted so as to to not slip and hold 12 lbs in the manifold.
The difference between a safe race and a bank of shattered pistons was close - In les than 15 seconds I could loose the lands between the rings and never hit over 5000 rpm.
Heat rise and detonation can be instantaneous.
Lucky for me - I worked at an Olds dealership, so I just grabbed a handful of pistons and a gasket set and - was back in business.

aerobat66-RCU

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I saw Kris^ run the engine and fly it today. I can vouch that there were many jaws that dropped when the tach was read. Keith, you have outdone yourself this time. Well done - it's a work of art.

My H9 Cap really wants this engine now!!

John

OSilfa

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..???!!!!

Onedesign1

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Kris....been meaning to ask you....what plane is that thing on?

Perry

JBrannon

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The first thing i noticed in the picture in your review was those beautiful big D shaped exhaust ports. From racing 2 cycle motor cycles and the Dart heads on my Big Block Chevy I know they will really flow.

Kris^

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The plane is a Fiberclassics 2.6m Extra 330LX, no lead added to achieve CG, batteries and fuel tank on cg with the rudder, choke, and throttle servos, plus receiver and wiring, at the back of the canopy area. Total weight of the plane is about 25.5 lbs.

The headers are made from stainless steel KS pieces, and 3.5" long, due to length restrictions in the fuselage, and the canisters are unmodified 50cc (per cylinder) Pefa canisters, which are definitley not enough "muffler" for this engine and have very small, and restrictive, outlet stingers.

I just received a 29-10 Mejzlik yesterday. It will be fun to bolt it on after the engine gets broken in, and see how things go. Current prop is a 28-12 Mejzlik, but I'll be trying out other props, like a Menz-s 28-10 and Biela 28-10 (when I get one) to see how the engine/airframe combination like them.

I KNOW that eventually I'll have to try a 3-blade, and my first choice will be a 26-12 Mejzlik or H. Fuchs.

LS171Malibu

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So Kris^...what is the inside scoop on the 55!!!

krayzc-RCU

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had a chance to see one at the triple tree this past weekend that is one small beast of a motor the one i seen had a menz 28 x 10 on there swinging over 6500RPM something like 6700-6800 i think....

what s up with the 55?

Kris^

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When I first installed the Xtreme, I re-used the 50cc (rated capacity) PEFA canisters that had been in my Fiberclassics 330lx, and worked well with the lower performance BME 102 Evo.

At Triple Tree this last weekend, ti was obvious that the engine was being held back by the canisters, that they did not have enough flow potential to match the engines exhaust output, and that the small diameter outlets would not flow well enough. To that end, I shoehorned a pair of 70cc (rated) Pefa canisters into the plane to replace the smaller ones. the larger canisters are about .75" larger in diameter, and within 1/4" of length, and use a .070" larger diameter outlet stinger.

RPM figures for the Xtreme, using the new exhaust, now match those quoted by BME when the engine was test run before being shipped. There is NO "tuning" of the exhaust for optimized power output, simply because there is no room for headers over 3.5" long. to properly "tune" the exhaust for max output would require a header of about 6.5-7". Still, the less restrictive "mufflers" (hardly a tuned exhaust now) now allow the engine to run as it should with regular "in cowl" stacks. With about an hours flying time on the engine, and about 1.5 total hours of run time, here is what it is now turning:

28-10 Mejzlik. . 6900 cold, and a solid 6800 when hot and after landing.
28-10 Menz-s. . 6350 cold and a solid 6250 hot.

I expect both of these numbers to increase about 200 rpm or so, as the engine breaks in. Idle is now smooth at 1100-1150 rpm, though a little burbly due to a slightly rich mixture. When I can get a properly "tuned" exhaust, in a larger plane capable of hold the exhaust system, I fully expect another 300 rpm (or more) from the engine. . That would equate to a Menz-s 28-10 in the 6700+ range. . . I'll let other people make quotes about the output of 3W or DA engines.

How's it fly? The term "STOOPID POWER" comes to mind. The Fiberclassics weighs about 26 lbs dry, or about 28 at takeoff. Pull up from takeoff, go vertical about 400 feet or so, do a quadruple snap, and keep going. Accelerate out of a hover and do a triple snap. . double snap. . another double snap . then stop climbing and come back down because the plane is a dot. . .Go vertical from takeoff and it just goes and goes and goes. . no bogging, no heating up, no slowing down. 15 seconds of vertical and you can barely see the plane.

Throttle response is very linear and smooth. . 1/4 throttle is really 1/4 power, and it's the same throughout the rpm/stick range.

I'll keep everyone informed on how this continues to progress. If i have not broken the motor by now. . I seriously doubt I ever will.

krayzc-RCU

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i want to hear about that 55

Kris^

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Call Keith at BME.

CAPtain232

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Hey Gerald......

I recently emailed Keith about it ('cause i've got 2 ordered and I am close to first on the list), but I have yet to hear back from him.
I will post any news that I receive.....unless someone else does first

krayzc-RCU

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thanks Jeff