I really like that plane RR whats next?

Hey Walther,
Next? Even I don't know that.
actually I try to work several projects at a time.
Not only do you always have another plane to smear the left over epoxy on,
but it seems always something to do on one while you ponder another.

Got the JackRabbit out again for several flights Saturday.
Put a much larger jisim ejection tube on the muffler and ran well.

I received my Peter Burford 6x4 props as suggested by Stewart and The man was right![8D]

I never spun one of those props up so fast, It is heads and shoulders over the master airscrew 6x4 I was beating the air with.

I didn't take any tach readings but the plane just ran better and faster and that little MPjett just sang.

I was just scared to put that pretty prop on a bellylander for risk of scuffing it (or worse ) but after flying it - no problem

Rob,
Ied be interested in tach readings with the PB prop. The thin blade section and the true pitch through to the hub should definately be more efficient for high RPM's.
Stewart

Stewart,
I was flying her again last weekend and ran a tach and was surprised to only read 15,500 rpm. It is tough to ground run this engine in this plane because it overheats with the cowl.
Next time I have it apart I'll mount it on the stand and I think the reading will increase.

Either that or the prop unloads a bunch in the air as the plane seems faster and louder (faster reving) in the air.

" Either that or the prop unloads a bunch in the air as the plane seems faster and louder (faster reving) in the air. "


Rob,
Actually I'm not surprised at the PB prop loading the engine more than the MAS under static conditions as its a very efficient design and thin blade section(thickness) will allow it to bite better than the thicker MAS paddle, but under flying conditions the thiner section should allow it to windup better due to its lower drag as it approach's its pitch speed.
A good demonstration that static RPM isnt the beall and endall of performance.
I have just builtup a Norvel AME 061 useing a new chrome type piston/cyl set which has little taper and a great piston fit , RJL diesel head and shows real diesel snapover( i bought 4 piston/cylinder sets and only the 1 set has this fit, the others are typical norvel fits), I think the PB 6x4 should work well on this too.
Stewart

Where are you getting the PB props?

From "The Man"[8D] himself

[link=http://www.peterburford.com.au/index.php]http://www.peterburford.com.au/index.php[/link]

While visiting his site be sure to read up on his engine and his manufacturing process.......

The props are priced and packaged 2 to a very nice padded box in 6x3 and 6x4.

This is a statement for the record as to which mass produced engine converted to diesel was the most powerfull. It was American and was the Cox and later K&B Conquest .15 with one of our conversions. Larry Renger the point man for Cox sent me 2 Conquests an R/C and Free flight version and an 8X4 Cox gray Propeller. We made a head and ran the prop on both engines and got 18,200 Rpm a great number. I called and told them the results and I got this response. "That's great, it as good as glow." Many years later I came across an article in the foreign notes by Peter Chinn. It was a review on the Conquest glow 10% and on a cox gray 8X4 the Rpm was 16,500 Rpm, what do you know! More recently there was an endurance free flight/R/C event to honer the a famous pioneer and the engine was the Conquest with our head and a then available Kraft Radio an all American system.

P.S. the three most powerfull engines are still American the Nelson, Jett and the fox.

Bob Davis
Davis Diesel

Hello Bob,
If you are telling me I can expect a DD/Conquest RC to turn a 8x4 at 18k well sign me up! I know I enquired to you if you had a head for the conquet some time ago, but as they say life gets in the way.....I've been enjoying your fine fuel for quite some time.

JackRabbit update.
I finally got around to trying to runup a bb engine and could get it to fire off a prime but kept wondering why I had no suction, another indication that all was not right was the fuel dripping out the side of the carb. Looked inside the side of the carb to notice my NIB engine was missing the idle needle[:@]

My 6yr old foster daughter really likes this plane and she watches the cd about the Cleveland Air Races with me and she knows all about the Jack Rabbit, Firecracker, Eightball, Goon, and Bonzo being her favorites (can't leave out Roscoe and his lion).[8D]

A fox .15bb does about 15,000 Rpm on a n 8X4 and over 11,000 on a 9x7.

Bob Davis
Davis Diesel

The Cox Conquest (a copy of the Australian Burford built Taipan 15 "Goldhead" ) is well known as a rather fragile engine as a glow and it's unlikely to have held together very long as a diesel at 18000rpm .There is a discussion of these conversions amongst some c/l F2C fliers at:

http://controlline.org.uk/phpBB2/vie...onquest+diesel

Apparently the rear races fail.

The Cox could have achieved 18000rpm as a glow by running much more than 10% nitro, I believe that the F1C fliers used to run about 50% and over with these engines. I would guess that they would have also had quite short lifes at these speeds.

Mine, in a c/l Goodyear eventually broke its piston, something which I later discovered was rather common.

Rossi (Italian) did a diesel conversion for their equivalent glow 15 and it was a much more powerful and reliable motor.

Locktite, Some very good and timely information.

Recently I was able to contact Ron Young (he had recently moved up to Sacramento area) and sent off all my Conquests to be run through and given the RY updates[8D] If anyone does not recognize his name - He was "The" works guru for the Santa Ana Cox factory.
In speaking with him, he mentioned the weak rear bearings, also that he was considering making another production run of ABC piston liner sets for the Conquests. If anyone else is interested in some P/L sets let me know so we can get this production run in the works.

Back to the Jack Rabbit!

Two weekends ago I was plagued by intermittent fuel delivery.
And packed up the plane and made a mental note to correct it. Then last weekend funny how the same thing happened again, then I remembered I hadn't sorted it out form the previous weekend's flight.[:-]

So last night I pulled the engine and dismantled the carb and deep within the spraybar was a splinter of wood which seemed to get sucked into one of the fuel supply orrifices.

Any way since I had the plain bearing engine out I decided to swap out my BB engine.

Looking forward to tomorrow's flights!