Centerline Thrust Prop Engined What-If

kitnut617 · July 10, 2006, 04:33:32 PM

would it look like. I've always like big powerful piston engined aircraft, and even more so if it had a conta-prop. I've always like the centerline thrust concept too so I tried to come up with something that if I had gobs of cash I would make an attempt to build.

Here are some photos of a model I've been working on and off for a number of years, I'm always changing it after I read something interesting about aerodynamics but it hasn't been changed for the last year or so at the moment.

http://groups.msn.com/TheWhatifandoddballm...to&PhotoID=2054

Cheers, Robert

Jeffry Fontaine · July 10, 2006, 04:44:26 PM

Looks impressive! For something that looks like it started life as a MiG-29, this is a real change.

Personally, I like the rear mounted propellers, but the pair up front are in the way. Getting all of the propellers installed on the rear would be the best option. Since you are going with the counter-rotation idea, why not take it a step or two further for the "UNDUCTED FAN" concept and have all four sets of propellers at the rear counter-rotating in unison to create the UDF effect.

What scale is this and what propellers are you using?

kitnut617 · July 10, 2006, 05:21:39 PM

Yes it started off as a Mig 29 and it's in 1/72 scale. I was looking for a particular airframe, it had to be modern and also the undercarriage had to be attached to the wings and not to the nacelles, the nacelles had to be removable without effecting the airframe.

There are three aircraft that were suitable. One was the Su.27, another was an F-14 and the last was the Mig. Studying references about all the big powerful fast piston engine aircraft reveiled that most of them had prop diameters of about 12 foot 6 to 13 feet diameter so this set the props on the model.

Once I removed the engine nacelles I increased the center section between the fins by five feet. My idea is it to have piston engines but of a modern design and I've been reading about the Rolls Royce Crecy engine, which was a twelve cylinder TWO stroke engine a little bit bigger than a Merlin but with twice the power. In the book ( which I got from the Rolls Royce Heritage Trust BTW) there are some interesting advanced engine concepts using the concept of the Crecy and these are 'X' configured 24 cylinders and also have theoretical power of 8000 hp. My idea is to have two of them sitting nose to tail in the rear fuselage with the front one using a shaft to the front prop and the rear one having the prop right off the gearbox. Where the engines were, I put a couple of radiator ducts which came of an F-82 Twin Mustang. The fuselage is from a Hawk. I've worked out how the undercarriage would be but I've not attached them yet as I've a bit more thinking to do on that.

The props came from the spares box where I had some left and right turning blades, I think some from my X/YB-35 kit.

Cheers, Robert

The Rat · July 10, 2006, 05:55:12 PM

You dirty dambuster you, where have you been hiding that beauty?! Crikey, she's a looker.

And while we're at it, are there any close-ups of that Jumo engined Meteor?

Captain Canada · July 10, 2006, 05:59:10 PM

Hey look ! That Sabredod stole my idea for Radmans Hunter !

Very neat...but I agree with JJ, the front props look out of place to me. But then again, I know nowt about this centreline thrust concept you speak of.........

kitnut617 · July 10, 2006, 06:27:14 PM

Hi Rat, the 'Jumo' engined Meteor is a Metro-Vick F.2 engined Meteor, actually it was called by it's code name, Rampage. This was the third prototype to fly and months before the first 262 was ever spotted. The Metro-Vick was an axial flow engine designed by Dr.Griffith of RAE. It was the direct ancestor to the well known Sapphire.

Here's some more photos of the build so far.

http://groups.msn.com/TheWhatifandoddballm...to&PhotoID=2058

Cheers, Robert

kitnut617 · July 10, 2006, 06:32:24 PM

QuoteHey look ! That Sabredod stole my idea for Radmans Hunter !

Very neat...but I agree with JJ, the front props look out of place to me. But then again, I know nowt about this centreline thrust concept you speak of.........

The Hunter is going to be a T.8M with the Sea Harrier radar nose.

Cheers, Robert

The Rat · July 10, 2006, 06:43:55 PM

QuoteHi Rat, the 'Jumo' engined Meteor is a Metro-Vick F.2 engined Meteor, ...

Gotcha. I should have read this page more carefully.

Tophe · July 10, 2006, 08:41:13 PM

Hello Kitnut,
I love your twin-boom central thrust model

Push-pull airplanes with 2 central double contra-rotating propellers have not occurred enough in the sad World called Reality, I agree. Fortunately, modellers' universe is correcting this lack... ^_^ 16 blades on the centerline is maybe the World top record ever...

The very modern use of piston engine is weird also, well as you have ventral air-intakes for cooling, one may imagine a turboprop version was possible, with ventral feeding of the engines. But I agree, this would be more classical, almost boring...
As a conclusion: I love your model!

BlackOps · July 10, 2006, 08:52:40 PM

Cool idea!

Jeff G.

GTX · July 11, 2006, 02:21:48 AM

Robert,

Your Centerline Thrust Prop job would make a cool modern day Reno racer. Nice work.

Regards,

Greg

Brian da Basher · July 11, 2006, 05:01:02 AM

Stunning concept and great execution!

Brian da Basher

kitnut617 · July 11, 2006, 08:30:23 AM

Thanks Guys, I appreciate all your comments and compliments

Cheers, Robert

kitnut617 · July 11, 2006, 09:01:09 AM

Quote

Very neat...but I agree with JJ, the front props look out of place to me. But then again, I know nowt about this centreline thrust concept you speak of.........

The centerline thrust is not a new idea, it being pioneered by Dornier. Most of their flying boats were this configuration. I think though the most advanced one was the Do.335. This was an amazingly quick aircraft where on one occasion a Tempest pilot came across one and gave chase, but was left behind very easily by the German pilot. It has been used by Cessna on their O-2 FAC aircraft and a couple of others which I can't remember their names right now, one is quite a modern composite business aircraft.

Cheers, Robert

Tophe · July 11, 2006, 10:07:35 AM

Quotethere are some interesting advanced engine concepts using the concept of the Crecy and these are 'X' configured 24 cylinders and also have theoretical power of 8000 hp.

Do you mean your model would have 16,000hp with a so tiny drag? Which maximum speed? 900km/h? (550mph?) What a thrill with piston engines...