Author Topic: Propeller (twin-boom) puzzle... (Read 5039 times)

Tophe · « **on:** December 11, 2004, 07:20:39 am »

Thanks to JeffryFontaine, a wonderful

what-if RAF fighter, twin-boom: F.18/37 Mk3 bubble-top, from the great Chandelle, Journal of Aviation History, at
http://www.chandelle-jah.com

(I will explain my problem reading the propeller drawing)

Tophe · « **Reply #1 on:** December 11, 2004, 07:21:29 am »

Oops, forgotten the picture:

Tophe · « **Reply #2 on:** December 11, 2004, 07:23:27 am »

I asked: how do you read the propeller shape? The standard and Mk.2 have 3 blades (length vertical on one side double than the oblical at 30° below horizontal), but I cannot decide the number of blades of the Mk.3 nor understand why one is skewed forward...

With Corel Draw software, I have found the answer more easily than I thought: the Bubble Mk.3 has an 8-blade propellers, and we can understand it precisely because one blade is skewed forward, allowing us to measure its length without being hidden (thanks to the artist)... A profile blade about 75% of the vertical length is at 45° above horizontal, not 30° (50%), so this is a 8-blade propeller, not 6-blade.

Tophe · « **Reply #3 on:** December 11, 2004, 09:48:18 pm »

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too bad they violated their mission statement with the political editorial by jumping on the kerry band wagon.

Thanks a lot, Steve, for directing us to this Chandelle editorial, that I had no read before, focusing on the F.18/37 and D-2 articles.
Some very interesting hypothesis inside. Maybe they are not true, maybe this was part of an electoral game, but it is very wonderful that USA actually allows for citizens the freedom to pretend (reveal?) things like that.
I think also that Historians can speak on both sides: details of the past / consequences for the present and future (not to commit similar mistakes again). This is the very reason of History course in our schools, I think.
As long as there are 2 opposite voices reading the events, we can hear both and decide by ourselves. This is my principle for Justice, and I am actually happy to see it is still the American way too.
(I do not mean at all that French owns the very right values - our Chirac President may go to jail after the fair trial for corruption following the end of his presidency, as well as the American President, I just don't know).

elmayerle · « **Reply #4 on:** December 11, 2004, 10:12:26 pm »

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Good site, too bad they violated their mission statement with the political editorial by jumping on the kerry band wagon.

I'll agree. Especially when he distorts things by only giving one side of both. Then again, I've had that debate with him before. Right after Columbine, he was all for completely disarming US civilians. He has good aviation material, though. I wish he'd make CD's available of all the past issues he's had up.

Tophe · « **Reply #5 on:** December 12, 2004, 11:33:27 am »

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F.18/37

I include my drawing of the Whittle-jet version, mentioned in the article and featured in my book "The end of Forked Ghosts".

Jeffry Fontaine · « **Reply #6 on:** December 12, 2004, 02:34:42 pm »

Tophe;

Thanks for the recognition.

As for the design of the propeller, I would have assumed that the power plant/propeller would have come from another aircraft program around that time frame. I would have assumed it to be a five blade Rotol similar to the arrangement found on the late model Spitfires and the Hawker Sea Fury. If they had gone with a different arrangement perhaps the contra-rotating propellers of the Martin Baker MB1 would have found themselves reversed and applied to the back end of that proposed aircraft.

As for Mr. Johnson's political views, let him whine.

Tophe · « **Reply #7 on:** December 13, 2004, 09:59:33 am »

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a place to discuss A/C. Then do just that.

I do...
Here is my Gloster/Whittle turned into the Gloster/Johnson Mk.3 ...

Gary · « **Reply #8 on:** December 13, 2004, 11:56:23 am »

That's cool Troph. Tell me, would it be an aerodynamic advantage to place the horz. stab on the top of the vert stabs? I'm thinking that this might minimize the propwash effect. And to make it perfect, counter rotators in the back. I think I'd like to build this beasty.

noxioux · « **Reply #9 on:** December 13, 2004, 05:45:49 pm »

Are we feeling our oats here? Can I feel that twin-boom contest looming on the horizon?

Tophe, how about a nice 3-view, and maybe I could take a few days and make a 3D version. I need the practice anyway.

Tophe · « **Reply #10 on:** December 13, 2004, 08:30:40 pm »

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place the horz. stab on the top of the vert stabs?
counter rotators in the back

So... here is the Gloster/Ifmfo F.18/37 Mk.4 ...

Thanks Gary!

And thanks to your country for this Corel Draw tool...

Tophe · « **Reply #11 on:** December 13, 2004, 08:40:54 pm »

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maybe I could take a few days and make a 3D version. I need the practice anyway.

You are right, and 3D virtual models belongs to my 2005-2006 objectives too. I have bought the rather cheap (compared to Rhino3D, AutoCAD...) RcCAD software and used several creations of their gallery
http://www.rccad.com/Gallery_MultiFuselages3.htm
But I still need practice, spending full days improving... Like in plastic modelism... (thanks to my friend Paul, a 1/72nd Twin-Whirlwind will be

)

Tophe · « **Reply #12 on:** December 13, 2004, 08:42:26 pm »

Oops... As we have changed page: I.m.w.f.o., your contra-prop T-tail F.18/37 is on page 1, illustrated...

Tophe · « **Reply #13 on:** December 13, 2004, 08:53:31 pm »

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add the prop from the hasagawa shinden

Well, the Hasegawa Shinden seems to have a 6-blade propeller, not 8 as 'Real'

But... what-if...

Tophe · « **Reply #14 on:** December 13, 2004, 08:55:43 pm »

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the Hasegawa Shinden seems to have a 6-blade propeller, not 8 as 'Real'

I mean: the original (imaginary) F.18/37 Mk.3 has 8 blades, I know the Real Shiden had 6...